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A Hybrid Owner’s winter survival guide




http://www.cleanmpg.com/photos/data/506/HCH_and_Prius.jpg
Manuel Santos - CleanMPG (http://www.cleanmpg.com/forums/../) - November 19, 2008

Preparing your Civic Hybrid and Toyota Prius for winter driving


As with most things in life, a bit of upfront diligence and preparation can do wonders later on. And on this note, nothing is more true than preparing your hybrid vehicle for the challenges of winter. For those of us who have extended periods of snow and ICE (http://www.cleanmpg.com/forums/glossary.php?do=viewglossary&term=28) during the winter season, any preparation should extend well beyond one’s driving habits and behaviors.




W A R N I N G


The information contained in this article is intended to mitigate the effects of winter driving particularly in sub-freezing temperatures. Using some of the recommendations under any other circumstances is not recommended and can even be dangerous. Please exercise caution and only proceed if you understand the goals and principles of these recommendations.



Front Intake (grille) blocking

Blocking the front intake grille on a hybrid vehicle is one of the most significant improvements that any hybrid owner can make to offset the inevitable loss in fuel economy during the winter months.



Why block the front grille?

On the Prius and Civic Hybrid the optimal performance range occurs when the gas engine temperature is between 60C and 90C. In between those ranges both cars offer additional stages of operation particularly in areas affecting electric propulsion, regeneration and fuel consumption rates. However, when the ambient temperatures fall below freezing , it not only takes longer for the vehicle’s engine to arrive to the optimal range, but sometimes depending on how low the ambient temperature actually is, it may not even reach ideal operation at all.
The main reason why this is so is because as the vehicle moves forward the colder air rushes into the engine bay and prevents the engine from warming up as quickly as it should.

Now, if we factor in the fact that the car is being operated by a human being, the climate control is also likely to be set to "warm up" the passenger cabin. This too helps deplete/steal the heat the engine is producing thus slowing down the warm-up process even further.

Because the Prius and HCH (http://www.cleanmpg.com/forums/glossary.php?do=viewglossary&term=24) have smaller engines, they also produce less heat since heat produced is a function of how little fuel gets burnt per unit of time. This makes these and other small cars more sensitive to cold weather operation and causes severe losses of fuel economy performance.



How to block the front grille?

Blocking of the front grille must be done safely and correctly. This can be performed with an after market kit or easily improvised in a matter of 30 minutes or less depending on the availability of materials.

The preferred method of blocking the front grille on the HCH (http://www.cleanmpg.com/forums/glossary.php?do=viewglossary&term=24) and Prius is to install properly sized segments of ¾ inch pipe insulation in the front grille openings. This pipe insulation can be bought at most hardware stores and is usually found nearby the copper tubing (plumbing section). A maximum of two segments is sufficient to perform the blocking on either car.


http://www.cleanmpg.com/photos/data/500/MS_Prius3G_FrontGrilleBlocked.jpg
Winter Blocking the 2010 3G Prius: Top blocking may require some creative cutting of the foam to ensure a secure and thorough fit. Bottom blocking only requires small vertical cuts on the foam to make it past the vertical fins and allow for a flush and secure fit.


http://www.cleanmpg.com/photos/data/500/MS_HCH2G_FrontGrilleBlocked.jpg
Winter Blocking the 2006-2008 2G HCH: Top blocking requires proper sizing and one vertical cut on the foam to ensure a secure and flush fit. Bottom blocking only requires small cuts on the foam to make it past the vertical fins and allow for a flush and secure fit.
2009-2010 HCH units: Require the use of a flattened out foam tube that is then cut to match the openings and then tied against the grille with nylon tie wraps.


First, identify how much of the grille to want to block. If you live in a particularly cold area you may wish to plan for full coverage of the front grille. Again, the blocking must match the conditions.

Second, purchase the foam pipe insulation segments you need and cut the appropriate segments. These segments may need to be notched with a sharp utility knife or scissors so that they can be properly inserted into the openings without bending over the grille cross members. This notching will make the segments look straight without making the grille blocking effort look bad or loose.


How much blocking do we apply?

Generally we want to be very careful when operating the vehicle above freezing temperatures especially if the grille is fully blocked. The optimal temperature ranges on the Prius and HCH-2 do not exceed 90C (194F) . Anything above 90C and the vehicles radiator fan will run, so it is in our interest to ensure that we gradually or completely remove the blocking if the ambient temperatures are too high. Failure to remove the blocking in warmer days will likely cause the engine to overheat and fail in addition to forcing greater energy consumption resulting from the operation of the radiator fan.

A very useful tool to monitor the actual engine temperatures is to use a ScanGauge device. It not only displays the engine coolant temperatures but also the intake temperatures which can help us determine the proper amount of grille blocking to perform. Of course, a ScanGauge has many other uses but in this particular scenario it is the best tool any Prius or HCH owner can use.

Here is some grille blocking guideline based on actual experiences in a 2007 Prius and 2007 HCH (http://www.cleanmpg.com/forums/glossary.php?do=viewglossary&term=24) over a 15-20 minute commute:

http://www.cleanmpg.com/forums/../photos/data/506/GrilleBlockingTable.jpg

Front Grille blocking as a function of ambient temperature


The table above was derived from average temperatures observed in both vehicles during the period of January 2007 to May 2007. The temperatures were recorded daily at the end of every commute as indicated by the ScanGauge II (version 3.0).

http://www.cleanmpg.com/forums/../photos/data/506/GrilleBlockingTableLegend.jpg

The above table values were matched to these engine temperatures




The Engine Block Heater


Most engine block heaters consist of a small “plug-like” heating element that is bolted into a specially designed port on the engine block. This diminutive heating element is as simple as it is effective and will heat up the engine coolant which in turn keeps the entire engine block at a temperature higher than the ambient temperature. Most engine block heaters provide a power rating of approximately 400 watts when operated at a household voltage of 110V.

http://www.cleanmpg.com/photos/data/506/prius_block_heater_small1.jpghttp://www.cleanmpg.com/photos/data/506/HCH_engine_block_heater_small.jpg

Prius and HCH-2 Block heater


Plugging in the block heater when the vehicle is parked will enable the engine to arrive to its optimal operational temperature sooner thereby benefiting fuel economy and lowering vehicle emissions. Of course, in colder climates the use of an engine block heater has many other benefits including reducing wear and tear on the engine components and reducing the need to perform warm-up idling among others.



Testing your Engine Block Heater

http://www.cleanmpg.com/photos/data/506/TestingBlockHeater.jpgHow do we know the engine block heater is working? Why would you want to know?
With time the Ebh (http://www.cleanmpg.com/forums/glossary.php?do=viewglossary&term=75) plug or its cord will develop a defect due to fatigue or simply because we tried to drive off while forgetting it was plugged in (I am guilty of this too).
You may choose an auditory test or a test with a digital multi-meter. An auditory test is possible in the first 20 seconds after plugging in the Ebh (http://www.cleanmpg.com/forums/glossary.php?do=viewglossary&term=75) cord to a live outlet. You should hear a faint crackling noise during the initial warm-up which is a clear indicator that the Ebh (http://www.cleanmpg.com/forums/glossary.php?do=viewglossary&term=75) is working.

When using a digital multi-meter set the device to measure resistance (ohms) and you should read 33-36 ohms when measuring the resistance across the two flat poles at the end of the Ebh (http://www.cleanmpg.com/forums/glossary.php?do=viewglossary&term=75) plug (don't do this with the car plugged in). If you do not read any resistance then the cord or plug may have developed a problem and may need to be repaired or replaced.



When to use a block heater, and how long to leave it on

http://www.cleanmpg.com/forums/../photos/data/506/IntermaticWallMountedTimers.jpgA block heater should be powered on long enough to make a measurable difference in how quickly a vehicle’s engine warms up. When already underway, the quicker the engine warms up, the sooner it will enter its efficient operating stages.
In the winter time the block heater may have to be "on" over a longer period of time, perhaps 6-8 hours or more in extreme cold temperatures. In the warmer months it needs much less "plug-in" time. For instance, for those that want the ultimate benefits of a block heater in the summer months, a 1-2 hour plug-in time should be adequate. Typically, block heaters can raise the temperature of the engine block by approximately 30C-40C above the ambient temps.

Leaving the block heater on for too short a period will help but will not materialize the fuel economy gains it is capable of. Conversely, leaving the block heater on for too long will amount to diminished benefits since much of the heat will be lost into the surrounding air while parked.

For this reason, it is usually a good idea to plug the block heater to a timer device that will control when and how long the block heater will stay on for. These timers should be able to handle 1000 Watts of power and they usually come in many forms and features. A home improvement store or Walmart will carry these which range in price from $30 to all the way up to $120 for the fancier models.




An example of two wall mounted Digital timers from Intermatic. Each timer controls a different car and each can have up to 7 distinct power ON, Power OFF programs for weekdays and weekends. Retails for roughly $30 each and saves roughly as much over a few years of operation.


The Tires

Even in winter, keeping the tires pressures up is very important for great FE (http://www.cleanmpg.com/forums/glossary.php?do=viewglossary&term=21) (fuel economy). Why? Because in colder temperatures the internal air pressure effect on the tire is reduced thus causing them to run flatter. Since a flatter running tire induces more friction on the road surface, we certainly do not want to neglect the air pressure in the colder days either.

So what is the best approach for maintaining the proper air pressure? Basically two approaches:
Regular use a good digital tire pressure gauge. Ideally check the tire pressures every 1 or 2 weeks.
Install and use a direct type Tpms (http://www.cleanmpg.com/forums/glossary.php?do=viewglossary&term=99) system.Now that we have a monitoring regime in place let us focus on the ideal tire pressures. The main determinant for setting the proper tire pressure is the tire’s own maximum pressure rating. This rating is present on the sidewall of every tire and should be used as the authoritative reference marker. The recommended tire pressure usually present in the vehicle’s door jamb and owner’s manual are not intended to favor fuel efficiency and tire durability. Instead these recommended values favor ride comfort which is critical element of a vehicles show-room and test drive appeal.

So, assuming that we identify the maximum tire pressure rating for the tires, we then establish a baseline setting for our vehicles that takes into account our FE (http://www.cleanmpg.com/forums/glossary.php?do=viewglossary&term=21) goals and comfort aspirations. For instance, if the maximum sidewall pressure rating is 44 PSI then we may pick a pressure baseline from the following table.

http://www.cleanmpg.com/forums/../photos/data/506/TirePressure-summary.jpg
Recommended scenario for winter tires with a maximum sidewall pressure rating of 44 psi


In many cases, it is quite possible to run the tires at a much higher pressure than the indicated maximum rating. However, care should be exercised in ensuring that the tires are not only free of defects (due to punctures and age) but that they are also used in a proper and controlled setting.
According to many studies the rolling resistance continues to decrease even as the tire pressure is raised beyond its maximum rating, albeit at an ever diminishing amount to such an extent that the FE (http://www.cleanmpg.com/forums/glossary.php?do=viewglossary&term=21) benefits may no longer make up for the lower peace of mind. In any case, and whatever pressure setting you choose please exercise caution when raising your tire pressures beyond the stated maximum rating in the winter months as the frozen tire structure is far less resilient.


Selecting the proper winter tire

If you have snow and ICE (http://www.cleanmpg.com/forums/glossary.php?do=viewglossary&term=28) on the ground you SHOULD NOT rely on the OEM LRR (http://www.cleanmpg.com/forums/glossary.php?do=viewglossary&term=36) tires to carry you and your loved ones your through the winter months. Even though the OEM tires offer unrivaled fuel economy in the summer months, they also are the absolute worst for operation in adverse weather conditions.

For your sake and that of others sharing the roads with you, make sure you swap those tires with good winter grade rubber. Ideally, you should have a set of cheaper rims (steel) where the winter tires are mounted; and when the warm weather returns you simply swap the winter wheels with the OEM set that came with your car.

Why a different set of rims for your winter tires? Because the OEM aluminum rims will get damaged by the winter time salt and sand that is spread on our roads. Such abuse is often noticeable after the first winter and does nothing to enhance the value of your vehicle as it ages. There's also the aspect of convenience since all we need to do is to switch the wheels twice a year which is often better, simpler and quicker.


Last thought on winter driving tires

Q: Isn't it possible that the "very best" all-season tire can be better than the worst and cheapest winter tire in matters of safety and handling ?

A: Definitely not ! In fact, several regions in North America have made it illegal to operate a motor vehicle without appropriate winter tires.


And here's a site containing a set of videos that will expose the inadequacies of all season tires in winter driving:

Be Tire Smart (Full tests of Winter tires v.s. All-Season) - MUST SEE (http://www.betiresmart.ca/video/apa.html)

Tire Rack Tire Test - Winter/Snow vs. All-Season vs. Summer Tires on Ice (http://www.youtube.com/watch?v=GlYEMH10Z4s)



Recommended Winter tires

Michelin X-ICE (http://www.cleanmpg.com/forums/glossary.php?do=viewglossary&term=28) – These offer good wear, class leading safety with effective adhesion and minimal impact on fuel economy which is a VERY tall order from any other winter tire brand. This brand/model is absolutely recommended for both HCH (http://www.cleanmpg.com/forums/glossary.php?do=viewglossary&term=24) and Prius vehicles if you value safety, enhanced fuel economy performance and low noise levels.

Please note that most snow/ICE (http://www.cleanmpg.com/forums/glossary.php?do=viewglossary&term=28) tires are directional in that they can only be driven in one direction. This means that they can not be rotated as easily and in the same pattern as the OEM tires. To do so will compromise the handling and safety of the vehicle in adverse conditions.
Look for any embossed arrows in the tire sidewall to indicate if your winter tires are directional. When in doubt, call your dealer or tire shop to make sure.



The Engine/Intake Air Filter

During the winter months the engine air filter gets very dirty on the account of extra pollutants present in the air. These pollutants consist of various substances that range from road salt to silicates and other chemicals produced through the exhaust of other vehicles. Many of these substances are present in higher numbers in the air for many reasons and they are often quite hard to avoid. By having a clean air filter we are ensuring that not only the engine breathes more freely but also that we protect many downstream components such as:
Valves and cylinder seals
O2 Sensors
EGR valves
Catalytic converter
Exhaust system
http://www.cleanmpg.com/forums/../photos/data/506/dirtyengine_airfilter_small.jpg
Can you guess which is the "dirty 1 year old" filter with just 10K miles ?


The most noticeable side effect that a cleaner engine can have on the performance of an engine during the winter months is the increase fuel economy performance. Not only because the entire combustion control system can more accurately administer the fuel to match the volume of air but also because the oil will breakdown far more slowly due to less foreign substances and hence promote reduced engine friction.

Basic maintenance rules call for a yearly inspection of the air filters and a sooner replacement than the manufacturer recommended interval if the filter shows the presence of dirt.



Oil and viscosity ratings

This is without as doubt, a top perennial issue regardless of season and temperature. A higher quality low viscosity (the lowest your vehicle can accommodate) is always preferable and is no less important in the colder winter months. For your HCH (http://www.cleanmpg.com/forums/glossary.php?do=viewglossary&term=24), make sure you are using Honda’s 0W20 or other similarly rated synthetic. Using any other oil rating on the HCH (http://www.cleanmpg.com/forums/glossary.php?do=viewglossary&term=24) will lead to extremely poor fuel efficiency and faster engine wear.

http://www.cleanmpg.com/forums/../photos/data/506/hch2-0w20hondaoil_small.jpg http://www.cleanmpg.com/forums/../photos/data/506/Prius-Mobil1_0W20_Oil.jpg
Honda oil used on my HCH-2's and the Mobil 1 0W20 used by dealer on my Prii



On the Prius, consider using a synthetic oil and if you feel adventurous you may contemplate using a 0W20 as well – I did so with the cooperation of my dealership and so far the results are very good. I have been using 0W20 oil on my company Prius vehicles without any ill effects but some dealers will not agree to the substitution. Nevertheless, check with your dealer first as from a warranty fulfillment perspective it is better to be safer than sorry.


Windshield washer fluid

This seemingly trivial fluid can at times become a head ache for many drivers especially if the fluid is heavily diluted in water. When driving though colder weather it is important not to ignore the freeze resistance rating of the fluid. Blocking the front grille can also have a positive influence on the temperature of the windshield fluid as it enables the engine cavity to retain more of the heat produced by the gas engine while in operation.

http://www.cleanmpg.com/forums/../photos/data/506/windshieldwasherfluid.jpg
Typical winter rated windshield washer fluid


Windshield washer fluid can come in a variety of colors (blue, green, yellow, pink, etc) but the most important attribute of suitability is that anti-freeze rating. The rest is a matter of brand, cost and color.

Don't forget to inspect the windshield washer tubing for leaks as the alcohol contained in the fluid can compromise the integrity of hoses and wiring and connectors in the engine bay. Just to make sure, test your nozzles regularly especially after a good wax job since excess wax or paint sealant may build up and clog the spray/squirt nozzles.



Re-fueling your vehicle

There aren’t many things we can do when it comes to winter gas formulations. Even those of us who live in the warmer states/provinces end up having no choice when it comes to consuming this type of winter gas. Despite the benefits that these gas formulations offers the average driver, a loss in energy density in unavoidable and always contributes to lower fuel economy.
Despite this, we can still minimize the impact of these winter formulations by following most of the sensible care and maintenance advice and also by selecting fuel brands of higher quality – which are commonly – referred as Tier 1 brands. As usual, the Shell brand does appear to offer some consistency in the quality of their gas in the summer months which not surprisingly also extends to the winter months as many of us can attest.



Washing your car in the winter

No. This is not a joke. Maintaining your car clean in the winter not only will allow it to look good but will also allow it to travel lighter and more efficiently. Focusing on the wheel wells, fenders and under-body is quite helpful as those areas can carry a pretty hefty load of ICE (http://www.cleanmpg.com/forums/glossary.php?do=viewglossary&term=28) and snow. A study performed several years ago found that an average vehicle can carry as much as 60 lbs (or more) worth of packed ICE (http://www.cleanmpg.com/forums/glossary.php?do=viewglossary&term=28) and snow for several weeks with a significant negative impact on fuel economy.



Managing window fogging and ICE (http://www.cleanmpg.com/forums/glossary.php?do=viewglossary&term=28) on the windows
Using the defogger and climate control

The defogger is standard equipment in our hybrid vehicles and can be used when the windows are fogged up or laden with ICE (http://www.cleanmpg.com/forums/glossary.php?do=viewglossary&term=28). However, using this equipment will come with a severe cost to our fuel economy as many of us can attest with our experiences. In any case, if you must use any of the defogging equipment do so strategically and do not forget to turn it off when its job is complete. In most scenarios you should be able to turn off the defogger after the first 5-10 minutes and then rely on the climate control system to keep the cabin environment under control. If used appropriately, the climate control should be able to monitor the temperature and humidity factors and manage the use of heat and air conditioning quite efficiently

Typical defogging/de-icing scenario:
Turn on engine.
Set climate control to auto and temperature to the lowest possible level
Turn on the rear defogger
Do not turn on the side mirror heaters.
Start moving the car as soon as the forward and some rearward visibility improve and it is enough to allow safe driving.
Turn off the rear defogger as soon as possible
Lower the fan rate on the climate control and do not raise the temperature beyond its minimum. Believe it not, the minimum temperature is pretty warm in a very cold day. ;)Other alternatives

But what if, you could do something that prevents the fogging and icing to begin with?
Yes, there are a multitude of options available to us and it only takes a little bit of preventative care to really make a difference. For instance, we could apply (as I do) a bit of Rain-X defogger to the interior of the windows. On the outside, we can apply a good amount of Rain-X ICE (http://www.cleanmpg.com/forums/glossary.php?do=viewglossary&term=28) or another glass (or paint) sealant and that will enable the windows to remain clear under light snow or freezing rain. For overnight protection – especially for those vehicles that sleep outside-, you could locate a windshield blanket (protector) and all you need to do in the morning is sweep away the snow and lift it off before driving away.

http://www.cleanmpg.com/forums/../photos/data/506/RainX_DefoggerAndIce.jpg
Rain-X Rain and ICE (http://www.cleanmpg.com/forums/glossary.php?do=viewglossary&term=28) repellent, and Rain-X interior Window Fog repellent



http://www.cleanmpg.com/forums/../photos/data/506/No2Snow.jpg
Windshield blanket from No2Snow



http://www.cleanmpg.com/forums/../photos/data/506/SNO-Shield.jpg
Windshield blanket from Sno-Shield



http://www.cleanmpg.com/forums/../photos/data/506/WaganEL2324Snowbrella.jpg
Windshield blanket from Wagan



Its too cold out there. Lets just warm up the car before driving off.

Turning the vehicle ON and idling it before driving off is never a reasonable option. It is bad for the vehicle and its emissions system, bad for the fuel economy and bad for the environment. Do not do it under any circumstances, no matter how tempting or brief it may appear to be.

Do you have or want a remote starter in your hybrid?
If you don't have a remote starter but you wish you had one, please do not bother looking for a reputable shop to install one in your Prius or HCH. In addition to the underlying technical challenges of a safe and viable retrofit you still have to contend with your warranties. As per the most recent information from either manufacturer, there are no such devices approved for use in these vehicles and the after market install (or attempt to install) will likely interfere with the manufacturer's warranty.
In any case, a remote starter shamelessly defeats the design and usage goals of these two vehicles, which are predicated on using less fuel and polluting less.



Driving your hybrid for fuel economy in cold weather

While your hybrid instrumentation may be the source of your greatest pride during the summer months as you marvel at your skill and fuel efficiency capabilities of your hybrid vehicle, it can also be the source of your greatest disappointments in winter time driving. For those who do not drive long enough distances for the engine to warm up, it can be quite depressing to look at the poor fuel economy numbers which depending on the circumstances, can be two to three times worse that what you got in the previous summer.

However, despite the realities of winter driving in cold weather it is important to continue driving by your instruments and avoid complacency. Yes, your cold weather fuel economy is worse but anything you do to mitigate that, will always be worth the effort in terms of fuel saved and the lowest emissions possible.



The Hybrid Specific Operational Stages

The Toyota Prius and the Honda Civic Hybrid II have a variety of operational modes that are mainly governed by temperature thresholds. The primary temperature inputs are acquired from the engine and various sensors in the conventional and hybrid power train systems that help determine the final behavior and performance envelope. Obviously, this article is not intended to be a detailed overview of the algorithms and I doubt many of us would be able to use this information during regular driving.
With this said, many of us have found this temperature driven behavior perplexing and even frustrating especially when the cold weather arrives. The following tables attempt to illustrate what is going on and what to expect when the temperatures fall.

HCH-2 Operational Stages

First let us focus on the HCH-II as it appears to have a more complex operational profile. The following is the definition of the operational stages:

http://www.cleanmpg.com/photos/data/506/HCH2_OperationalStages_-_Definitions.jpg


In the table above you'll notice that Stage S3 actually defines the fuel cut-off level which allows for Auto-stop to occur. However, at very low temperatures (below -18C/0F) the Auto-stop will not occur at all.

The following two tables attempt to identify the two primary temperature inputs that drive the transition from stage to stage:

http://www.cleanmpg.com/photos/data/506/HCH2_OperationalStages_-_Temperature_Transitions.jpg



And lastly and more significantly, the next table defines the available transition map:

http://www.cleanmpg.com/photos/data/506/HCH2_OperationalStages.jpg


From the point of view of an HCH-2 owner, the fourth stage (S4) is the ideal stage to be in. In this stage we can evoke a soft glide at will, we have good regenerative affinity and the EV glide and Mid 3's mode will be at their most ideal levels. In the winter months particularly during the colder days you may find it difficult to see this stage in short drives unless you use a block heater and block the front grille. On the coldest days you will be lucky if the system allows for stage S3, which includes AutoStop, and using the FAS technique will be the only way to truly prevent the ICE from idling.

Also note the managed modes: S0 and S5. These modes can occur as a consequence of the two primary temperature inputs (Engine temp and Outside Air temp) but there are several others that begin to raise their head. For instance, MCM, BCM and DC-DC module and sensor temperatures have a very strong bearing on how quickly and severely these arrive or go away. Again, I will avoid going into too much detail here as describing these additional thresholds would only help complicate things more than they are already.

What do these tables mean for the average HCH-II driver ? If anything, the transition map table should provide clues as to what preparations one should take throughout the entire year in order to operate on the car's most effective range - especially if one does low distance or City only driving. In the winter, one should do anything that safely brings stages S3 and S4 earlier into the picture. This means:
Strategically blocking your front grille
Using a block heater
Adding additional insulation to the engine bay
EtcIn the summer, it is also OK to do some of these things - with moderation, of course - including using the block heater. Remember that starting the vehicle straight onto these ideal stages will be off-limits for the first 10-15 seconds after the car is booted.



Prius II operational Stages

In contrast to the Civic Hybrid II, the Toyota Prius II appears to be far less complex in terms of its handling of the temperature. Of course, this does not mean that the system does much less work at all. If anything, this means that the Prius does an awesome job at hiding the inherent complexities of the HSD system.

The following tables were derived from my experiences and confirmed by the approximated findings of so many others Prius II owners. As for the Prius, the following table establishes the known states and definitions that are already well know in the public domain, but I have to admit being tempted to add a Stage S0 to indicate "Reduced to no electric MG assist" in very cold temperatures.

http://www.cleanmpg.com/photos/data/506/Prius2_OperationalStages_-_Definitions.jpg


The following table establishes the observed primary temperature thresholds that the system appears to be governed by.

http://www.cleanmpg.com/photos/data/506/Prius2_OperationalStages_-_Temperature_Transitions.jpg



And finally the Temperature Transition Map as a function of the temperature ranges.

http://www.cleanmpg.com/photos/data/506/Prius2_OperationalStages.jpg


For a Prius II owner seeking the best fuel efficiency and lowest winter emissions, the goal is to reach stage S3/S4 as soon as possible. This means that if an engine block heater is used as well as effective grille blocking the odds that you will meet that operational stage are pretty good for the broadest part of the temperature range I illustrated. This of course is subject to the length and duration of the trip but the thresholds are somewhat less ponderous and more relaxed than what Honda picked for the HCH-II.

Since in my case the internal combustion engine will be running almost full time during the colder winter months, the typical Prius owner will benefit from a careful application of the throttle in order to keep the engine RPM as low as possible. But since the Prius does not have an OEM tachometer, I find the ScanGauge II device an absolute necessity.
Equally important is the careful monitoring of your SoC and strategic avoidance of hard assists or even EV mode (if you manage to reach stage S4) especially when the temperatures are really low.

What do these tables mean for the average Prius-II driver ? If anything, the transition map table should provide clues as to what strategies one should chose throughout the entire year in order to operate on the car's most effective range - especially if one does short distance or city only driving. In the winter, one should do anything that safely brings stage S4 earlier into the picture. This means:
Strategically block of the car's front grille
Use a block heater
Add additional insulation to the engine bay
Monitor your throttle input and watch your RPMs with a Scangauge II when the gas engine cannot shutdown.
EtcIn the summer, it is also OK to do some of these things - with moderation, of course - including using the block heater. Remember that the goal remains to reach S4 as soon as possible. ;)



Is there anything else that can be done to help improve our fuel economy and lower emissions even more?

Sure there is. Consider installing an inexpensive solar panel on your Civic Hybrid or Prius. This helps, because during the winter months the power demands on your 12V battery always increase and yet the battery capacity decreases due to the colder temperature!

Obviously, this deficit is a significant contributor to reduced fuel efficiency as many hybrid owners can attest to when their 12V batteries begin to fail. To help supplement the losses a solar panel setup for your Prius or Civic Hybrid (http://www.cleanmpg.com/forums/showthread.php?p=236784#post236784) will offer several benefits:
Even if just for a few hours a day of sun or a full day of cloudy skies, a solar panel setup will help prevent dramatic and crippling losses of charge on the part of the 12V battery. Please remember that your car is slowly draining the 12V battery after you lock it and walk away from it.
Maintains and extends the life of your 12V battery. Keeping a battery topped off is a sure way to ensure its long life and flawless performance for many years.
Helps improve fuel economy by reducing the amount of generated energy that gets diverted from propulsion purposes to charge the 12V battery.
During the summer months it can also help power an inexpensive cabin cooling setup (http://www.cleanmpg.com/forums/showthread.php?t=22764&page=2) that can further save even more energy.

So, which car is best in harsh winter operation ?

Sorry. I am not answering that one. For me it is sufficient to regard both cars as the very best on the market today and I am happy & satisfied with whichever I happen to be driving. ;)


As a conclusion... and in no particular order, here are a few final thoughts:
Allow the higher RPM of a cold engine to power the car with the least amount of throttle input possible.
If you have a choice of itineraries, consider one that allows for lower speeds – even if the distance may be marginally longer.
Do not idle your vehicle when stopped. Shut it off or at least place it in neutral. By placing it neutral the fuel consumption rate needed for idling is often cut in half.
Avoid using EV (http://www.cleanmpg.com/forums/glossary.php?do=viewglossary&term=30) or EV (http://www.cleanmpg.com/forums/glossary.php?do=viewglossary&term=30) glides unless your SoC (http://www.cleanmpg.com/forums/glossary.php?do=viewglossary&term=31) allows for a good fuel economy “moon shot”.
Maximize your regenerative opportunities over greater distances and avoid panic or aggressive stops.
Know your car and how it behaves under colder temperatures. Understanding the warm-up stages and their thresholds can help you decide when and how to apply the most effective setup and driving strategy. Please see the operational stage tables above.
Avoid operating the climate control/heater at a maximum temp setting in the first 5-10 minutes while the vehicle is warming up.
Watch your tire pressures. These can vary dramatically as the ambient temperatures swing downwards.
If possible and if you have one, plug your engine block heater in several hours before driving off. More plug-in time may be required in colder temperatures. If you don't yet have a block heater consider purchasing one and have it installed. More often than not it is worth the hassle in more ways than one.
Do block your front grille (intake). It is not that hard and the benefits are too significant to ignore.
Monitor the charge level of your 12V battery and recharge it as soon as it drops below 12V. Remember that in the colder weather the power demands increase while the battery capacities decrease.
Include an ice scrapper with a soft brush to remove ice and snow. A small shovel may help clear the path in case of deeper snow.Again, don't hesitate posting any feedback or other valuable tips. ;)


Cheers;


MSantos

Manuel:
Excellent information! Clear and concise as expected!

Great! Thank you for the time spent putting this together.

Great article Manuel, and there are plenty of tips that a non-hybrid owner can apply as well. I've discovered that on cold days (like -30C) with a cold windshield, my -45C rated washer fluid can still freeze on my windshield. I am thinking that the alcohol in the fluid evaporates, leaving behind only the water which quickly freezes. Either that or the fluid is optimistic with its rating. Does that ever happen to anyone else? I usually use the cheap stuff from CT or Wal-Mart when it goes on sale and am wondering if the brand has something to do with it.

If it is blue, it is usually very diluted around here. I like to use something called "Purple Power" -- I've had good results with it.

since my portable garage was a dismal failure, i think i will look into one of those windshield blankets........

Excellant article! Thanks for the effort.

It raises one question for those of us down south. For partial blackage (50-60%) do you recommend blocking the top or the bottom? Or does it matter?

Thanks again,
Frank

Block the top first, for aerodynamic benefit. You can block it completely, even in the heat of summer. (notice that I'm in Texas...) There is more than enough cooling capacity with only the lower opening.

Try partial blocks on the lower once the upper is covered.

Another fantastic article MSantos.

I had the same question concerning blocking 50% of the grill. Did you block the upper or lower when you ran the tests?

I blocked only the lower today and found much better results than having the full grill blocked.

Thanks again.

Hi Jess and Frank;

I actually block the bottom part on the grille first and then proceed to block the remaining portions above. The main reason I do so is because the bottom parts make up the longest spanning applications of the foam tubing and not surprisingly, also happen to be the most difficult to insert and remove.
Not that the whole setup is difficult at all, but the upper segments are smaller and hence easier to insert and remove as required.

Also according to my observations over the last few years, manipulating the bottom first yields the most dramatic results on the HCH as well as the Prius.

However, I do agree with Andrew regarding the aero-dynamic reasons to do the top first especially if you have a daily highway routine. Since I am 100% city there's no advantage to start from the top first and only the convenience factor seems to matter to city slickers like me. :rolleyes:


By the way: Keep checking this thread as I will be adding the Warm-up/Operational stages for both the HCH-II and the Prius-II... sometime this week or weekend (or as time permits).


Cheers;

MSantos

Manuel -- that sounds like an excellent addition! Please add a response post when you do so that this thread pops up in the updated listing and people take another look.

Yes, please post so the subscribed get an email too!

Manuel,

Any opinion on supplementing a coolant heater with an engine oil heater?

Wolverine is one brand I've found online. Their typcial heater is a rubberized heated pad, that is bonded to the underside of the oil pan via peel-and-stick adhesive, and then similarly to a coolant heater there is a 110 volt power cord run out through the front bumper grill.

Thanks in advance.

Hi Mendel;

That is a pretty good question and the Wolverine unit sure looks promising for a lot of folks who either cannot or do not want the hassle of a block heater installation.

Here are my thoughts:

In order for these "pads" to be effective they must (ideally) be installed in a clean and relatively flat surface. This is especially true for the high powered models.
It appears that the best ones for small cars are rated for 200-250 Watts (??) and seem to do a good job of "baking" the oil... they seem to do it for roughly half the electrical load. So yes, at first these would appear to be more efficient than your typical EBH rated at ~400 watts.


Frankly, I don't know if a wolverine pad would give me too much of an advantage. I noticed that in very cold days the surrounding air just steals much of the heat produced by the block heater and things only get worse (with increasing diminishing returns) the longer the unit remains plugged in. But the combination of the two would definitely heat up the engine block faster for sure. Also, a worlverine pad would not be a problem for me since I do not drive on gravel roads nor do I go off-roading. :D

Then again, I am of the opinion that water remains a better thermal conductor and because of that I still see the EBH as a device with greater merit. Just my opinion. :)

Cheers;

MSantos

Great owner's manual for the winter!

If I may add, if you are getting your oil changed at a dealership, make sure to specifically request the 0W-20, otherwise you may get the "standard" oil that is in their bulk tank which more than likely is 5W-20 or 5W-30.

Toyota & Honda dealerships should have 0W-20 in quart bottles and many dealerships now have 0W-20 in bulk. Just make sure you ask for it.

Hi all;

HCH-2 temperature dependent operational stages added. Prius temp stages coming up (they're a bit simpler) ;) ...


Hi skoh:

I often suggest people use the 0W20 oil requirement as the ultimate technical litmus test on whether a dealership is worthy of any post sales business. You should not have to ask that they use 0W20 at all. But if this is the only way they will do the right thing, then unless you do not have a choice look for another dealership that is not only more technically competent but also more concerned about the impact a lesser oil will have on your car's FE.

Cheers;

MSantos

Great charts, MSantos. All these behaviors of the HCHII cold, I have witnessed. However, it's nice to know, now, why and/or when they may occur.

I appreciate you "opening our eyes" to the reasons for these behaviors. I used to think it acted like it had a mind of it's own and therefore out of my control. I guess it still is somewhat out of my control though, but not as much as I had previously thought. ;)

Thanks again,

Jess

Great article Manuel. But, of course, I have a question or two. :)

At the moment we are sitting in the "early morning sub freezing, daytime high low 40s F" Is "66%" blocking OK or do we need to be on the safe side (no scan gauge) and stick to 50%?
Your chart was for 10 - 15 minute commute. What about a LONG interstate drive. Same temps as above. Does the higher speed force more cold air through so a 75% block would be preferable?


At the moment, I have both cars blocked upper and 1/2 lower. After seeing your chart, looks like I better take out one of the uppers.

Thanks,
Bruce

Hi Bruce;

That is a good question.

I would still consider getting a Scangauge II at some point since one never knows what is truly happening to the engine temperature. Lets say you leave in the morning and it's cold - no problem. You return in the evening and things are warmer, this could be a problem.

Still, I would venture to say you could block 75% without much concern if the ambient temps are closer to the low end of the the boundary I identified in the chart (32F).
Things really begin to warm up as you approach the upper boundary (59F) and at that point the engine temps can easily exceed 194F after a while - which is NOT a good thing over the long haul.

Cheers;

MSantos

Hi All;

The Prius II temperature/stage tables were added.

Cheers;

MSantos

Most Excellent, as usual.

Manuel,

I blocked the top first because I was going out of town for the weekend. I blocked only the top to start with. It scared me a little as the ScanGauge said I went to 210 degrees F (99 C). This was peak. It stayed in the 200+ range though. However, when checking the temp on the main panel it was in the center. For the return trip I removed the blocks and saw the same temp's. The ambient was about 40-45 deg F in light rain both times.

I will follow your advice and start with the bottom this time as my normal commute is all city streets.

Do you think my ScanGauge is giving optimistic temps? What else could be causing this? Are these slightly higher temperatures a problem?

Your article is great. Just want to be sure I am not causing myself any major headaches later!

Thanks,
Frank

BTW, it appears that the goal would be to get into S4 as quickly as possible.

It would be great to have a set of motorized shutters to make this happen.

Frank

Hi Frank;

Do you think my ScanGauge is giving optimistic temps? What else could be causing this? Are these slightly higher temperatures a problem?

The ScanGauge temp readings are very realistic and pretty accurate. This is because the ScanGauge simply "reads" and "displays" the actual temperature values broadcast by the car's ECU.

Over the long haul you'll want to avoid very high temps. The short little stint now and then should not hurt too much.

Anyway, as we said many times before, the built-in engine temp gauge is the least accurate and often the least useful for folks like us.


It would be great to have a set of motorized shutters to make this happen.

Agreed... as long as the mechanism does not freeze and lockup after coming out of a car wash in a -30F winter day. ;)


Cheers;

MSantos

You wash a car on a -30 day:eek:

For that matter, a -30 degree day :eek:

Frank

-30C is about -22F... I've washed my Insight at -12F simply because the windows had a film (tried to clean them with Windex -- never again!!! :eek:) and the windshield washer nozzles were frozen shut. The wash fixed both issues and applied a film of RainX in the process.

I've been wondering about using some of those rubber blanket
heaters to gently warm hybrid *batteries* and get them to their
happy operating temps sooner, as a companion effort to using
an EBH. It would probably have to be mounted under the battery
box, involving pulling it out, and making sure no part of the
box would crush the heater, etc etc. Possibly easier in Honda
variants since the Prius pack tends to be a bit heavier, and you
probably wouldn't want much more than a heating pad's worth of
power -- 50 or 100 watts, to avoid cookin' 'em, esp. without
some kind of thermal feedback.
.
It would make a great addition to an OEM plug-in rig...
.
_H*

Holy macro. That is an awesome idea Al.

You know, I never really thought much about that but now that you mention it I see quite a bit of merit to such a project. You are right, at first it would seem easier on the HCH-II but perhaps not because of the weight (believe it or not they are closer in weight than we think)... but instead I would see it as a very rare packaging advantage for the HCH-II.

Placing the pad right on the IPU sturdy metal cover would not only heat the entire IPU (gently but surely, where the pack and the other temp sensitive hybrid control modules are) but also radiate a good amount of heat into the passenger cabin without any major dangers or overheating. All this would happen while the block heater is keeping the Stator/Motor reasonably warm and ready. Hummm

At first thought, the way I would approach this is to use a high current diode in the pad's power line so that the wattage is cut in half... or a wall switch style AC potentiometer to help dial in the power level feeding the pad. The power line would then join in with the EBH cord. Plugging in the EBH would mean plugging in the pad as well. :rolleyes:

On second though and unless I am missing something, I can't see why this would be any harder on the Prius-II either. hummm...


By looking here (http://www.wolverineheater.com/products.shtml) we see quite a few models that would make the cut in this application. The 50 Watt unit ($50) has a very small contact area and that concerns me a bit. However, the "battery heater" model ($40) may provide a bit of gentle heat - enough to work well on the entire Prius battery enclosure or the HCH-II IPU enclosure. Check out their thermostat. For $20 it would do well in preventing overheating.


Cheers;

MSantos

Randall made mention of an "IMA Battery heater" back in 01/2007... might be worthwhile finding out what he did for his Insight?

Holy macro. That is an awesome idea Al.
......................
On second though and unless I am missing something, I can't see why this would be any harder on the Prius-II either. hummm...Seems so to me as well. Could you not just stick one or two on the back of the bracket that surrounds the battery? It is easily accessed when the false floor is out and wouldn't involve ANY weight on the pads. Wouldn't warm as directly as if the battery was sitting on them but it would be quick and easy. Some of that heat would also seep over to the 12V and keep it as well. Plus, if you cart a dog around back there, it will have a pre-warmed floor! ;)

Thanks for all the useful info, Manuel. Who better to write this than someone from "Winterpeg" (that's Winnipeg, Manitoba to those not familiar with its common nickname).;)

A couple points:

I am not familiar with what "mid 3s" refers to in the HCH operational modes. I'm guessing it may be the 'lean burn' mode??

I notice that the rubber seal along the leading underside of the hood has a gap in front of the engine air intake. I assume this is intentional for warm weather conditions. It's possible that sealing the gap between the grille and the hood would feed warmer air into the intake. I remember when cars had a flap on the air intake to draw heated air off the exhaust manifold but I haven't explored the HCH intake duct to see whether it might have something similar.

Cheers,

Roger

Hi Roger;

You are quite right about the seal gap. Although I have not mentioned it before, I have actually covered that portion with cell foam tape: an - almost permanent - application which I peel-off for the summer.

The reason why I did not mention this before is because I am not quite done assessing the full impact that a warmer intake has on the HCH-2 FE during the colder days. I'll post some pics sometime this month after I have a "more empirical view" of its benefits.

The mid 3's is a high FE mode that places the engine consumption rate in the 3 L/100km range when operated in speeds ranging from 35km/h all the way to 65km/h. Many of us actually use this mode a lot. Mind you this is the avg FE, but in this mode you will easily see figures in the 2.2-3.9 l/100km range. This mode only occurs in stage S4... although I've had people telling me that they got it in S3... which is something I have yet to experience.



Cheers;

MSantos

msantos said "ScanGauge device. It not only displays the engine coolant temperatures but also the intake temperatures which can help us determine the proper amount of grille blocking to perform."

I monitor coolant temp with a ScanGauge in a Prius. What is a good range for intake air temps? What is too High?

Thanks

Hi Rokibler

I honestly don't know all the details yet. From the observations I made thus far and also from the input we get from many other owners, it appears that the intake air temp plays the smallest of roles and is often not regarded as the "low hanging fruit" many of us are looking for.

Honestly, I don't know what is too high in terms of air intake temp. The technical literature I have access to does not have any details on this. I would surmise that if there was ever a risk of reaching a high temp level then that would likely occur in the hotter summer months (?) ... and even then, I am sure there would be other aspects of the system that would experience thermal failure before the upstream combustion process falters.

Cheers;

MSantos

I'll speak from data collected with my Civic.

Mileage increases almost linearly with ambient (and intake) temperature, up to about 75 F. Above that, up to 100+ degrees, it's nearly level.

Thanks to msantos and the PaleMelanesian for your responses.

I'm getting hit with a battery recharge in nearly the same place every single day. I make sure the battery is full or nearly full by the time I get home for work. Because of the hills and the cold (down to 23 this morning) the car is very assist happy with no regen. This knocks the battery down to 5 may be 6 pips when I get to work. So when I leave work I have to climb a couple of more inclines and down the battery goes. This has happened everyday. Can't wait for the warmer weather.

Have you tried shifting to "sport mode" or "second 'gear'" for just a moment or the duration of that climb and feathered the pedal to keep it out of the pack?

Yeah, I've used the "S" mode a couple of times. It always seems to put some drain on the IMA pack. I did try it today going down an incline to a red light after just leaving work. That's usually when the recharge happens. I've tried the "S" mode one other time going up a hill, but the rpms shoot straight up to 2500 - 3000. I don't like that, so I never really use it.

No recharge today. I imagine it was the warmer temps, (mid 50's).

I bought an OEM car cover and I've yet to scrape the windows since I got it, even with temps down in the low 20's.

Hi Jess;

Kacey's suggestion has some merit especially if you use the S mode strategically - or as he said - "for just a moment or the duration of that climb".

Look at it this way:
As a negative, the RPMS go up and that disturbs the mostly quietly and serene drive the HCH-II affords. But the extra power produced by the higher RPMS during those "brief" times is also not all wasted.
On top of that, you often get a small energy surplus always diverted to the pack in the form of a micro-regen when feathering in S. But even when you don't get that regen because you need more power, the level of assist used is always less than the assist you would use when driving in "D" and that may be the key to enduring the climb without depleeting the pack at all.
On longer climbs you will deplete the pack for sure and there's nothing we can do about it other that to take advantage of whatever other opportunities you can control.

In any case, you lose some FE by using the S mode but the extra energy produced by a slightly higher reviing engine is still more efficient than the costlier to replace assist energy. If you were to get ALL your regens while going downhilll then, Yes... use the assist going uphill. But if a good deal of your regens come mainly from a forced regen, then the "S" mode is still more effective due to lower energy conversions losses you have to deal with.

Cheers;


MSantos

Ok, cool. I'll try it out next time it's really cold. It was 61 this morning but rainy. I did shift to "s" on a short but very steep incline and did notice the lack of assist with high rpm's. Unfortunately for me, my drive way is a small hill, and getting out of my neigborhood is a small hill. I'm taking a hit before I ever get going.

Thanks guys.

Jess

My neighborhood is a nasty uphill climb, I just grit my teeth and bear it, by the time I get to the freeway the car is up to AS temp and SOC is at 6-7 sometimes 8 pips.

Msantos,

Regarding snow tires and mounting them on steel rims, any thoughts regarding sources for steel rims. Also, if I look up something like San Leandro Honda's online catolog, I have to say I'm looking for Civic DX parts. If I say the Hybrid it just shows the alloy pizza wheels. I wonder if the brake assemblies etc are identical, and these still rims would fit the Hybrid ok. I suspect they would, but would be nice to know.

I've found it quite frustrating trying to find steel rims online. Local tire dealers say they can sometimes find take-offs for around $88 per.

Also, back in the day semi-presentable silver painted steel rims were readily available, with push-on center caps. With the advent of wheel covers (which don't come cheap, and tend to get chewed up), it seems all that's available (when you can find them) are these very utilitarian looking black rims with myriad holes around the circumference. Putting them on, without center caps, and with the (non-acorn) lug nuts that come with the Hybrid doesn't look that hot. No big deal, they would work, but it's too bad you can't get the old style silver rims with center caps, much more presentable.

I would think it takes somewhat higher technology to make a steel rim, compared to alloy, what with metal stamping/rolling, and automated welding requirements. Maybe that's part of the issue?

Hi Mendel;

The 8th gen Civic DX steel rims will work beautifully. In fact, that is exactly what I use along with the wheel covers and lug nuts (just four per wheel). Many Honda dealers will offer pretty good deals on the winter combos which often includes the tires: Michelin X-Ice (my favorites) for little more than $800.

Frankly, I am a sucker for Honda genuine parts and a total fan when they undercut the quotes from other tire shops who simply couldn't tell if the rims fit unless I actually buy them ahead of time. :eyebrow:

Here's a picture of mine:
http://www.cleanmpg.com/photos/data/500/HCH2_WinterWheels.JPG

Cheers;

MSantos

Thanks, MSantos. I'll check that out in more detail. The last time I was in our dealership I asked casually, and they said steel rims were "around $100".

Might be next year though: everyone seems to be selling out of Winter tires, at least of the more popular sizes. Both the Quebec legislation and a cold snap we've been experiences on the west coast are likely part of the cause.

On the coast it's always a bit of a quandry, it doesn't get that cold, and it doesn't stay white that long. This year's shaping up as an exception right now though.

****

Just an update: picked up some honda civic steel rims (p/n: 42700-SNE-A01) and Nokian WRG2: a world of difference from our Bridgestone Insignia Se200's (with 60,000km wear). Skipped the wheel covers, so they look a little funky ;)

Regardless of your tires, if they don't touch the ground firmly, you can get yourself really stuck. Up until 1/2 hour ago (when the blessed snow plow finally arrived) the most difficult part of our excursions in our '06 Civic Hybrid was getting out of our driveway and into the "grooves" in our side street.

We've had a full *foot* of the white stuff on the ground, for a few days now. It varies around town a bit, but for sure we're getting a White Christmas :)

At first we were thinking the small spoiler under the front bumper was the lowest point, but looking under there I would say the plastic underpanel is the low point, and it seems to deflect down below the regular underside a fair bit.

If you're the lowest riding car in the neighourhood you're going to be brushing against the fresh snow all the way to the plowed main streets.

If I get ambitious I might put it up on jack stands and see just what the difference is with/without.

MSantos,

Could you do me a big favour and check your steel wheel part numbers against the following. I have already the Honda rim (06 Civic DX 15", 5-bolt) steel rim:

42700-SNE-A01, DISK, WHEEL (15X6J) (CMC/CLA)(BLACK)

and it has worked out fine, with winter tires mounted. I'm thinking to dress it up per your above picture ;). I believe the cover is:

44733-SNE-A00, TRIM, WHEEL (15")

But for nuts I'm a little confused. I've found 2 part numbers:

90381-SV1-981, NUT, WHEEL (SATO RASHI)
90304-SA0-981, NUT, WHEEL (FUSE RASHI)

Is one of them correct? And does the nut need the plastic retaining ring, and is that included?

Mendel, this is what I have:

44733-SNE-A00 ............... TRIM, WHEEL 15x6J ................. $50.03
90381-SV1-981 ............... Wheel Nut, COMP..................... $4.84

The steel rim part number includes the wheel cover since it is a Civic DX part.
The wheel nuts are should be purchased in sets of 4 since we will use the OEM locking nut as the 5th. That means a total of new 16 wheel nuts at almost $5 a piece.

Cheers;

MSantos

Thanks, MSantos.

MSantos, when you get a chance, could you please take a look under your HCHII:

Looking in the shop manual (which I believe you said you have) on page 20-145, the right side column is titled "Front Floor Undercover Replacement". These appear to run from the Front Undercover to the Middle Floor Undercover.

I don't have these. Do you?

Yep, I do - on both sides (left & right) - and on both cars.

The page number you mentioned is for the 2006 shop manual only. The 2007 and 2008 shop manuals have the same illustrations but on different page numbers ;)

Sorry, I did not bend down to look under the car yet. Its -33 out there (-45 with the windchill) and the garage floor communicates that very well. :)

Cheers;

MSantos

Thanks, MSantos. Hmm, I think I'll be talking to our dealership. We have the engine compartment shield, referred to in S.M. as "Front Undercover", then just bare till "Middle Floor Undercover".

I've now seen in several places here at CleanMPG a common misconception that I'd like to weigh in on. On nearly all modern fan motors there is a resistor which acts to enable the slower fan speeds when present(each level below max/high). To elaborate, in the old days (don't ask me to look it up I don't have the details) you had a separate coil/motor for each fan level. This scenario would offer a truly different level of electric demand for each fan speed. However with the use of a resistor you can have multiple fan speeds using only one primary motor. This is obviously a huge efficiency in terms of space and parts. The resistor works by converting the surplus electricity into heat. The heat is disappated into the air flow of the climate control system.

The downside is you are always using "high" power regardless of the fan speed. This concept is evident to anyone who has ever had their climate control blower motor resistor fail, as the only speed that works is high. By the way, the lower the fan speed you use, the more you are "resisting" and the quicker your resistor will overheat and burn out (I found this out after I formerly would leave it on low for extended periods and went through a lot of resistors).

Now I've always been a believer in coming up with a solution when you discount someone else's idea, so in light of what I mentioned above, here is what I do to maintain maximum efficency in my vehicle:

Summer time operation - Given the fact that my 2 year old is with me 90% of the time I'm in the car, A/C is pretty much a given. I'm not willing to make him suffer. But I do cycle the air on and off to maintain a comfortable temperature without excess. Here's what you can do. Slide the temperature scale all the way to coldest; never move it from this position. If you have a "MAX" selector use it, otherwise there should be the presence of a fresh air vs. recirculate option - go with recirculate. MAX and recirculate are essentially the same thing. They function to take the existing cold (or in the winter - warm) air from the cabin and further chill (or heat) it. This is clearly much more efficient that taking the hot outside air and asking the system to cool it down. Now with recirc on, temp on the coldest setting, and the A/C button engaged, switch the fan speed to "High". Using high is the most efficient because it allows for the maximum heat transfer (away from and out of the cabin) in the quickest possible way - and you're using the same amount of electricity you would be using on low, medium, or high. Once the desired temp is reached, switch off the A/C button. This will disengage the compressor, the highest workload on the A/C system. Continue to let the fan blow for up to about a minute as you will be taking the remaining coldness off the system and moving it into the cabin. Once the air coming out is close to the ambient temp of the cabin, them completely switch off the fan. Repeat as desired.

Hi Mike;

Is there a particular vehicle you are referring to (does it have auto climate control) ?

I agree. In the more common fan/blower configurations the resistors can get pretty hot when operated at their lower settings and resistor failures are somewhat normal. In the winter, those failures can obviously be more frequent since we're continuously drawing in hot air over the resistors which only helps make things worse for the resistor in use... but in the summer the equation may change a bit especially is the AC is mostly on.

Cheers;

MSantos

MSantos,

Good point, I did not take into consideration newer "auto" climate control systems which I am less familiar with. The suggestions given were toward the convention climate control systems still used by the majority of conventional automobiles. You are correct though - auto CC systems are becoming more prevalent especially on newer vehicles.

Having used them only sparingly when say renting a car, I think the concepts would still be similar. Say for example you have one where you set the actual desired temperature as a digital readout (i.e. 70 degrees). Using that example, the system will add warm air from the heater core (hot coolant flowing through) to mix with the cold air from the evaporator to dispense comfortable air flowing into the cabin. This is highly inefficient. Settings the temperature to the coldest setting (likely to be 55-60 degrees) and then completely turning off the system once the desired temp is reached would be much more efficient. Again, this works most efficiently in the reverse for winter time. Setting the highest temperature possible (combined with recirculate) will prevent the system from adding cold outside air to the very hot air from the heater. Cycling on and off will reach the same end result (comfortable cabin temp) while maintaining much greater efficiency.

I have to say I have no familiarity with the CC systems on hybrids whether they use the same technology or something dramatically different.

I think in this case, it has more to do with the warmth it is stealing from the coolant than the actual fan motor drawing too much current (as far as an impact on FE).

Since the HCH-II has auto climate control, the fan speed in "infinitely" variable so it isn't switching on a resistor bank but probably has some sort of pulsed modulation for controlling the fan speed (just guessing here).

In the summertime, using high fan speeds with the AC only signals to the ECU to use both mechanical and well as electrical compressors to cool down quicker, limiting the fan speed (by selecting higher temps in "auto" mode) will only activate the electrical compressor and leave the hungrier mechanical belt-driven compressor unused.

In the winter here in Quebec (usual temps in the -10C range (10F)), I tend to dial in the degrees to 21C (70F) but leave the fan speed at 1 or 2 pips until I reach the highway.

When the car is warmed up, leaving it in "recirculate" mode will usually fog up your windows pretty quick unless the AC is on....

Daniel

Also using the defroster will activate the belt driven side of the Hybrid A/C Compressor

New here. Love the site and especially the article on winter driving etc.

I had two winter tires installed today on the front of my 2008 HCH. I had wanted to get the Michelin X/ice but they were not available, probably due to the press they got here.;) Instead I purchased two Goodyear Ultra Grip Ice (P195/65R15 89Q). I went with replacing only the front tires because I am not concerned about braking or cornering, just about getting started from a complete stop etc. So far I can really tell the difference from the stock tires.

Has anyone else used these particular tires, and has anyone else just put winter tires on the front? I only plan on keeping them on through March. Pros/cons to only putting two on? I suppose I would pop for two more if convinced or if I have problems with handling. This is my first winter with the HCH as I drove a CRV the past five years.

I love the HCH though. I drive equal amounts of city/hwy miles, about 350-400 miles per week. I drive tenderly but don't cause problems in traffic when it's heavy. I usually get 45-47 mpg, double what I was getting with the CRV, and I'm very happy with that.

This blocking of the grill interests me so I think I'll check with my private garage in Omaha, they only work on Hondas and are very knowlegeable.

It's great to be here at your site.

ken

"because I am not concerned about braking or cornering"

Maybe you should be ;)

On our very first car I just got snows on the front, close to 30 years ago now. I recollect going down a snowy hill and trying to slow down a bit, touching the brakes. Just about went into the curb. I honestly don't know what difference snows on all four would have made, but the consensus today is to go with snows all-round. Some places won't even sell you anything less. There's some salesmanship in that, but still: 4 snows is better/safer.

Welcome, Ken! It is good to have you. :)

Stick around -- there is a wealth of information about your vehicle here and much of it deals with how to get the best fuel economy available from it, as well as maintenance aspects.

I've now seen in several places here at CleanMPG a common misconception that I'd like to weigh in on. On nearly all modern fan motors there is a resistor which acts to enable the slower fan speeds when present(each level below max/high). To elaborate, in the old days (don't ask me to look it up I don't have the details) you had a separate coil/motor for each fan level. This scenario would offer a truly different level of electric demand for each fan speed. However with the use of a resistor you can have multiple fan speeds using only one primary motor. This is obviously a huge efficiency in terms of space and parts. The resistor works by converting the surplus electricity into heat. The heat is disappated into the air flow of the climate control system.

The downside is you are always using "high" power regardless of the fan speed. This concept is evident to anyone who has ever had their climate control blower motor resistor fail, as the only speed that works is high. By the way, the lower the fan speed you use, the more you are "resisting" and the quicker your resistor will overheat and burn out (I found this out after I formerly would leave it on low for extended periods and went through a lot of resistors).


I had to replace the resistors on mine. I usually left it on 2, and when it burned out, 1 and 2 didn't work while 3 and 4 still did.

I tested this. With the engine off, each notch of the fan speed dropped the voltage another 0.1V. Then, turning it back down each notch allowed the voltage to rise by 0.1V each time. So high fan IS drawing more power than low fan in my car.

Volts ........ Fan speed
12.3 ........ Off
12.2 ........ 1
12.1 ........ 2
12.0 ........ 3
11.9 ........ 4

I tested this. With the engine off, each notch of the fan speed dropped the voltage another 0.1V. Then, turning it back down each notch allowed the voltage to rise by 0.1V each time. So high fan IS drawing more power than low fan in my car.

Very interesting, I stand corrected. I wonder if the resistor is actually working to bleed off SOME of the electricity (but not all)? Maybe it also has a buck circuit to impede the voltage at a corresponding rate to the resistor's load (so that the resistor does not have to work so hard?). I guess I'll have to check this myself tonight.

I don't know why. I'm sure they are burning some power into heat, because the resistors do burn out so easily. This is my second car to burn out the #2 resistor, leaving only 3 and 4 working.

I don't know why. I'm sure they are burning some power into heat, because the resistors do burn out so easily. This is my second car to burn out the #2 resistor, leaving only 3 and 4 working.

I think there-in lies part of the answer. On my 2000 Maxima (and several other vehicles I have had resistors go out on) a blown resistor results in fan speed of 4 (high) only. You on the other hand are left with two fan speeds. My laymens knowledge would say this is the return of the dual motor. That is to say I'm speculating motor 1 controls fan speeds 1 and 3 with a 1 stage resitor, while motor 2 control fan speeds 2 and 4 with a 1 stage resistor. There could be other configurations but you get the idea. This is in contrast to other vehicles which have one motor and a three stage resistor. More likely though would be the one resistor is wired to both motors - otherwise two resistors would had to have burned up simultaneously. Other that that the answer would be there have been dramatic changes in the way resistors perform, which I am not aware of.

I could be wrong, but I had assumed that for each lower speed, it added another resistor, like this:
Speed 4 = no resistor
speed 3 = resistor 3
speed 2 = resistors 3 and 2
speed 1 = resistors 3, 2, and 1
0 = switched off

Since resistor #2 burned out, both 1 and 2 didn't work.

For the record, it was a Mazda truck and a Honda civic that both lost settings 1 and 2.

Boy don't I feel like I dope. I always knew what resistors did and understood their working through personal experience but that was it. I think you're completely right. My experiences though must have always been in relation to resistor 3 (per your illustration) going out, while would disable fan speeds 1 through 3. I just assumed the whole thing was wired together somehow and if part of it failed the whole thing failed, but your explanation makes perfect sense. I guess it also makes sense that resistor 3 would go out the most since it is used more than any other. But it's totally possible to have other conbinations of failure as well (just resistor #1 or #2 as in your example).

I'm just guessing. I didn't replace it myself, so I've never actually seen the unit.

Sorry for the digression, all. Back to winter, I saved myself from window scraping this morning by using a whole-car cover last night. Roll it up, put it away, and drive off, leaving frost everywhere else but on the car.

In the mornings and afternoons I have been FASing at stop lights b/c the car has not warmed up yet. However, I have had a forced recharge every day. For experimentation, I have left the engine running in neutral at lights when the car is cold. I take a small hit to the FE, but I have avoided the forced recharge!
And this afternoon with the battery at 5 bars, assist was not avail for a few minutes, even though it was at first. It wasn't forced recharging, but the system eventually warmed up and with some general recharging the system was assisting again. The battery eventually bumped up to 6 bars. It was such a pleasant experience b/c it normally will assist until the battery is depleted and then it will forced recharge. It's like it realized that it needed to stop the assist until it was able to recharge the pack some more to avoid forced recharging

So far, throwing the car into neutral vs. FAS when it's cold is a better option. As MSantos has stated before the battery takes quite a hit when it's FAS and cold.

I also noticed it's very difficult to increase the SoC when it's cold out. It took me the whole 15 mile commute to bump the battery to one bar. In warmer weather recharging it to full capacity is a non-issue.

Jess

...
I also noticed it's very difficult to increase the SoC when it's cold out. It took me the whole 15 mile commute to bump the battery to one bar. In warmer weather recharging it to full capacity is a non-issue.
...

Hi Jess;

I suggest you try the following next time it is cold and you're just starting the car:

Start the car and accelerate gently for roughly 15-20 seconds up to a lower speed of at least 12 MPH and no more than 25 MPH.
Then for a very brief moment gently apply the smallest amount of pressure on the throttle and withdraw it just as fast without slowing down. You'll notice that a 1 bar regen will appear and stay on. If you are having trouble getting it to appear then a brief shift to "S" will usually do it as well.

When coasting and it is very cold you may find that the regen brakes don't work at all. To increase the dynamic regen affinity under these conditions simply switch to "S" until the regen appears then switch back to "D". From this point on the brakes regen will work. Note that this incresed regen affinity will be short lived and sometimes not even work until the vehicle reaches Stage 2 of warm-up.

Cheers;

MSantos

... I guess it also makes sense that resistor 3 would go out the most since it is used more than any other. ...

Resistor 3 should get hottest only in speed 3. Lower speeds should lower the current, and heating varies with the current squared, so temperature rise should fall off sharply in the lower settings. Likewise, R2 will be hottest at speed 2. Of course, R1 is used only at speed 1.

For my entire adult driving life, my default fan setting has been Speed 1, to try to maintain positive pressure to prevent dust and and CO from leaking in any holes. (As a kid, I watched gravel dust absolutely pour in through weatherstripping gaps around the door. As a young adult, I heard about one or two cases per year of children sleeping in the back seat being found dead of CO poisoning. Maybe these were the reasons I got car sick so often as a child.) But in more than three decades of driving, with the fan nearly always on, I've never had a fan speed control fail.

But in more than three decades of driving, with the fan nearly always on, I've never had a fan speed control fail.

Stay tuned on this one. They seem to be making them cheaper these days. I never had a problem for years of driving (with the same sytyle as you of constantly leaving the fan on low) but then had them go out on both household cars recently (plus lots of other reports from friends and work vehicles). An indicator may also be vehicle make/model as when I used to wash cars for Enterprise I saw more than a dozen go out on GM vehicles.

msantos:

great article. I've sent several people here for guidance.

One point occurred to me that might be worth mentioning. Those who have garages used to store stuff should make other arrangements and park in their garage. Particularly for attached or heated garages, there are multiple benefits. 1. Higher starting temp (with or without the block heater). 2. Tolerable cabin temp thus avoiding heater use during warmup. 3. The day's ice & snow can melt off, avoiding cold weather washing. 4. Warmer, dryer car is more likely to be maintained properly (tire pressure, fluids, etc.) 5. Never have to scrape ice in the morning. 6. Since our dog lives in the garage, she gets more love and affection and behaves better.

My Tacoma gets pushed outside whenever we do a home renovation. My 1.5 mile commute then yields 10mpg on a cold (10F & below) morning. Parking indoors, blocking the grill, and not running the heater yields 15mpg in the same conditions, a 50% improvement. EPA city = 17mpg.

Anyway, love the info, even for non-hybrids. Less grill block at a given ambient temp for non-hybrids, I'd say.

Then for a very brief moment gently apply the smallest amount of pressure on the throttle and withdraw it just as fast without slowing down. You'll notice that a 1 bar regen will appear and stay on.

I tried this today and it works. I took my foot off the gas and gave it a quick tap and down came the bar of regen. Awesome. I was able to charge the battery from 5 to 7 bars today.

Still no forced recharges since I have not FAS at lights when the engine is cold. I've been driving most of the commute, with hills and all, on 5 bars of battery. I've also resisted using more than 2 bars of assist on accelerations and increased the rpms going uphill to avoid using assist at all.

Thanks again MSantos.

Jess

I tried this today and it works. I took my foot off the gas and gave it a quick tap and down came the bar of regen. Awesome. I was able to charge the battery from 5 to 7 bars today. ...

Hi Jess;

Nice to know that it works for you too.

Also note that there are times that it does not appear to work, especially in warmer days but however unsettling, it may actually be working and before you know it your SoC will climb just as well. This is what we call an induced hidden (or micro) regen and the scangauge LOD reading will usually help confirm it (high LOD readings) ;)

This is essentially what I do everyday when the engine is still cold and it really helps. I usually arrive to my destination with 7 bars SoC and recently 8 bars after I got the latest software updates.

Now if we could just as easily tap the throttle to make this psycko -33F weather go away ;)


Cheers;

MSantos

Hi MSantos,

After 2 weeks my dealership has come back with "no dice" regarding the (apparently) missing panels, and this was Techline's decision. I'm composing a letter to Honda Canada (attn. Customer Relations).

The panels in question are described as "Front Floor Undercover", run from the engine covering panel down left and right sides to some short panels in the vicinity of the gas tank (we do have those panels)

I believe the part nos for the missing panels are:

74656-SNC-AOO - COVER, LEFT FRONT FLOOR (LOWER)
74606-SNC-AOO - COVER, RIGHT FRONT FLOOR (LOWER)

So just to recap, we have a long bare stretch down both sides on the underside, the middle portion of the car.

Other than a letter, can you think of anything? Or something pertinent to include in the letter?

Hi Mendel;

I don't know if I can do much in this area as the vehicle was "accepted as delivered" and that is something similar to what happened to other first year model owners in other areas.

This was a problem common to 2006 models, particularly vehicles shipped to US and Canada in that there were elements of the car's documented equipment that were not present. For instance, in your case you report you did not have the lateral mid section aero panels. This one I never heard of... perhaps because nobody noticed it before? Anyway, both my cars have the full set of aero under shields.

The other area I was referring to that affected earlier 2006 owners was the lack of a trunk lid lining. In later production batches this item was included but those who got the car with it missing were out of luck (myself included). The technical reason was that the trunk's left and right arm that allowed the left and right garnish to snap securely into the trunk arms had a missing pre-drilled hole.

There may be a reason why the panels were not included in your vehicle. I would study the underside to see if they can be attached at all and as documented. In your particular case I suspect you may be subject to an assembly time limitation and there may not be much more Honda can do at this point.

In the case of the missing trunk lid liner, I ordered the parts myself and I made the holes in the appropriate places. The lid liner snapped in very easily and it looks like a million bucks. You may have to do the same I did, as I doubt Honda will authorize the dealership to do it on their time.

Cheers;

MSantos

Thanks for the detailed reply MSantos.

I've started a thread on the subject in the HCHII section, I realize I'm sort of off-topic here. Harold has chimed in that he also does not have these mid-section panels.

Regarding the trunk lid lining, I assume this would like kind of like the black fiber panel lining under the engine hood. I have no trunk lining in mine, but see a number of round high points with holes, assumably to accept the push-in fasteners.

I guess to some extent Honda is victim of their lack of consistency: if they supply in some instances, and omit in others, the non-recipients feel burned.

I'll check out the underside for push-in fastener hole locations.

Thanks again for the tips.

Update: looked under there: looks like I am missing fastener holes, at least the ones for the intermediate fasteners, so that's likely the end of it ;(

Another question around winter driving: As I understand it, if you're going to leave the engine on at a stop light, it's better to do so in N than D. When the HCH II is very cold and I put it in N, it revs higher than in D. It it using more gas when it revs higher in N? Am I better off just leaving it in D?

Thanks,

Jess

Hi Jess;

Yes, it is revving higher in N than it does in D but it does not consume more at all.
Also, this only happens while the engine is in warm-up stage S0 or S1. After this, the engine will consume far less in N than it does in D, sometimes amounting to half as much.
When the stop light is long then switching to N is always a good thing to do.
However, for short stops in very cold days switching to N may offer little advantage since the CVT will need extra time to engage and we definitely do not want to abuse the CVT's forward clutch, especially if you want to move forward quickly as it is the case with many folks who drive in stop-n-go traffic.

Cheers;

MSantos

if your pack isn't full you can also switch to "L" for a tiny boost

Oh, ok good. I definitely leave it in D when I know I won't be sitting long. Thanks Manuel.

Kacey, I'll try switching to L and see how that goes, thank you.

I really like getting that 1 bar of regen to drop in the mornings. It's like the magic little bar and by the time I get to work I easily have charged the battery to near full capacity even in 16 degree weather.

One other thing I noticed in the winter is that I rarely see the battery go down to 2 or 1 bars before it force recharges. Lately when it recharges the battery is at a "low" 5 or 4 bars. It then quickly recharges to 7, but not 8.

Funny, I have had this car for over 2 years and still surprises me at times.

Jess

Hi Msantos.

I have received a written response from a customer relations specialist with Honda Canada. He tells me that the long intermediate left and right underbody panels "are not available on Civic Hybrids produced for the Canadian Market".

He points out that Honda reserves the right to fine tune the build sheet for various countries they sell to. He cites for example that heated mirrors are standard in Canada, but omitted in the States.

I've noticed other variations over the years with various Hondas. Often the disc brake design varies, for example. Some of these component variations can be frustrating and alienating to potential customers. The heated mirrors for example: I have heated mirrors on the west coast of Canada. Meanwhile someone in the northern central US, where they might be useful, does not.

The block heater keeps coming to my mind, as a current accessory, that should be standard equipment. It is an expensive hassle to add post-sale. My dealership more-or-less threw the instructions away, and leveraged up the quoted price. Also, any after-sale install just wastes perfectly good anti-freeze.

Anyway to get back to my original issue: two other Canadian HCHII owners have responded that they also do not have these panels, in the thread I started on this question. However, you report that you do have the panels on your '06, and your wife has them on her '07. Were these 2 Civic's regularly purchased, through Canadian dealers?

If your purchases were through regular Canadian dealership, I think I'm still flogging a dead horse, but I'm just curious ;)

The '09 leather equipped US models do have heated mirrors finally.

I just wish the timer for the defrost actually worked, many times I'll forget and the only reason it gets turned off is because I'm restarting from a FAS (when the car kills all my darned 12v electronics GRRR)

Hi Msantos.

I have received a written response from a customer relations specialist with Honda Canada. He tells me that the long intermediate left and right underbody panels "are not available on Civic Hybrids produced for the Canadian Market".


My Civic may have recently demonstrated one reason that Civic Hybrids produced for the Canadian market do not have the panels. We had a rare snow event yesterday and when driving home I started hearing a scraping noise from beneath the car whenever I passed over a "dip" in the road. I stopped to look for the source of the noise and discovered that water had penetrated the joints in the panels and subsequently froze. This caused the retaining pins on both panels (on both sides) to become unfastened, allowing the panels to drag.

I'm about to call the dealership and discuss this with them. I would like to think that since both sides became damaged at the same time they would see this as a design issue and fix it at their cost.

bernieball,

Sorry to hear about your problem, and hope it's resolved by the dealership. I purchased the mid-panels we were missing, and put them in myself. So far no issues.

One thing I can think of for your issue: the panels lap over top of the next one at their ends. They should be installed so that the panel nearer the front-of-vehicle covers the next one in line, kind of like shingles on a roof. Maybe one was reversed?

The panels were in place when I purchased the car new and I'm pretty sure that they were correctly installed. Either way, there isn't anything that one could do to keep water out. I guess it would be helpful to minimize the amount. :eyebrow:

The panels are setup to shed/drain any water that gets in the area but I believe that water on the road was just above freezing and the spray just started creating a series of very thin ice layers that built up. Something had to give and thankfully it was the fasteners/pins. I had to use a car wash's power nozzle and about 4 dollars in quarters to break up the ice. The pins were about 1.90 each and I only needed 4 so I'm not set back too much.

That's probably my first issue in 74K miles (I think).

New here. Love the site and especially the article on winter driving etc.

I had two winter tires installed today on the front of my 2008 HCH. I had wanted to get the Michelin X/ice but they were not available, probably due to the press they got here.;) Instead I purchased two Goodyear Ultra Grip Ice (P195/65R15 89Q). I went with replacing only the front tires because I am not concerned about braking or cornering, just about getting started from a complete stop etc. So far I can really tell the difference from the stock tires.

Has anyone else used these particular tires, and has anyone else just put winter tires on the front? I only plan on keeping them on through March. Pros/cons to only putting two on? I suppose I would pop for two more if convinced or if I have problems with handling. This is my first winter with the HCH as I drove a CRV the past five years.

I love the HCH though. I drive equal amounts of city/hwy miles, about 350-400 miles per week. I drive tenderly but don't cause problems in traffic when it's heavy. I usually get 45-47 mpg, double what I was getting with the CRV, and I'm very happy with that.

This blocking of the grill interests me so I think I'll check with my private garage in Omaha, they only work on Hondas and are very knowlegeable.

It's great to be here at your site.

ken

I highly recommend the Goodyear tires mentioned above. They worked great and my mileage did not go down at all. I do plan on purchasing two more to have a full set for next winter, and I do not expect mileage to be affected. Sams Club has them for $91.00 each. Not too shabby.

With the onslaught of the freezing temperatures many of us are once again gunning for our winter toolkits and last year's "know-how" in an attempt to keep the FE losses at bay.

It is with this in mind that we updated the "A Hybrid Owner’s winter survival guide (http://www.cleanmpg.com/forums/showthread.php?t=17560)" to not only demonstrate the winterizing of the 3G 2010 Prius but also add/tweak a few other tips.

More pics will follow in the upcoming two weeks. ;)

I will also be seeking to publish a few additional pics regarding the winterizing of the 2009 HCH and the 2010 Honda Insight as soon as I get a chance ;)

Cheers;

MSantos

I just bought new pipe insulation. I have since removed my front decorative plate and cut the insulation to span the width of the lower grill, blocking any openings.
We have already had mornings in the mid 40's! Looking forward to the updates!

Jess

Thanks, MSantos! This is a great article, and I learned a lot about how these hybrids drive from it.
Just one question: do any of these tips work for any other cars? There seems to be a lot of articles about the HCH-II and the Priuses in this forum, but I drive a HI-II; is there a big difference between my car and the HCH-II?

Thanks

Miles

Hi Miles;

Except for the temperature transition tables and the amount of blocking foam you use, there should be no difference between your HI-II and the cars referenced in the article. In fact, most of this stuff applies quite well to any other modern car too, if you are willing to ignore the hybrid specific stuff.

With this said, your car does have a unique temperature transition table that is definietly not shared with the HCH-II. While the number of stages/states remains the same, the temperature thresholds have been moved around a bit (for the better), so ... If you block your front grille, pay good attention to the Outside Air Temperature as that is the one that shows the greatest improvement.
In other words, the HI-II will perform better than the HCH-II at lower temps ;)

Cheers;

MSantos

MSantos,

I'm considering getting the Rain X Anti Fog, but I've read a lot of reviews that claim that it doesn't work or it worsens the situation. Is there something that they are not doing to allow this product to work? How has your experiences been with it?

Jess

MSantos,
I'm considering getting the Rain X Anti Fog, but I've read a lot of reviews that claim that it doesn't work or it worsens the situation. Is there something that they are not doing to allow this product to work? How has your experiences been with it?


I tried it once and it was horrible. It was worse than a foggy window. The defogger did not work at all on removing it and I had to wipe off the condensation.

The regular Rain X on the other hand is one product that really works. Dont even need to use the wipers in the rain 99% of the time.


I'm wondering if anyone has use the sno shields? I know it will work on preventing ice but what about fogging? I'm thinking about getting one.

Hi Jess and Jay;

In my experience, the anti-fog Rain-X product is a bit tricky to apply and it took me a couple of tries to get it just right. First, we have to make sure we apply it in a heated garage and then we have to make sure that we completely wipe off any excess. Doing so multiple times will help a fair bit and I usually only have to do it once every winter.

One side effect of the product is that even though it does help prevent fogging, it also promotes water beading via condensation when the interior humidity is just too high.

In other words: Instead of allowing the tiny water particles to remain in suspension on the windshield (fog), the product actually promotes the formation of larger beads which may slide down the glass (not good). I avoid this by maintaining a good amount of strategic air circulation inside the cabin.

Yes, the regular Rain-X is a far more tolerant product but it too needs to be applied under the proper conditions and the right way to offer maximum benefit. I apply both in multiple coats just before the arrival of the sub-freezing temps.

Cheers;

MSantos

I think I'm going to pass on it. I have some Rejx though that I'll reapply to the windshield. I have the week off, so maybe I'll just do the whole car. :D

Thanks you!

Jess

I live in the Washington DC area and talked to my Honda dealer about installing an engine block heater in my HCH II hybrid. He said it would have no impact in warming up the engine faster in the winter. He claimed that the HCH II does not circulate the engine coolant until the engine is warmed up so heating up coolant prior to starting it is useless. He also said that partially blocking the engine grill would not help either. He had never heard of any HCH II hybrid owner in my area installing an engine block heater of blocking the grill.

Confused?

Hi dhilldiner;

I guess I should be confused, but sadly this is not the first time I learn of deficient and unfortunate statements by some dealers.

I am sorry to say this, but the dealer is not only wrong on most counts but they also fail one of the most basic elementary tests... and short of telling you that you avoid this dealer at all costs, I would at least suggest you watch them carefully whenever you service your vehicle at their location. Personally, I would seek a second opinion from an alternate dealer. For me, a smarter and more informed answer would seal the deal.

While I am an ardent supporter of good dealers and the good service and value they often offer to hybrid owners, I have nothing but contempt for those who fail this miserably.

Cheers;


MSantos

Block heater is not heating the radiator's coolant, but rather the engine block (hence the name).

Hybrids are even more able to benefit from EBH and grill blocking than conventional cars, since they better exploit the warm engine.

Use of the block heater for a couple of hours results in at least the top of the radiator being warm to the touch, in my experience. That's one of the feedbacks I use to verify it's working.

There is a mechanical valve in the coolant line, referred to as a thermostat, that prevents flow of coolant through the radiator until the temp has risen, essentially to speed engine warm-up.

But as mentioned by ksstathead, the coolant being heated by the block heater is within the engine area, literally at the coolant drain bolt location on the engine. With convection currents, the warming coolant warms the entire engine and any coolant in connecting hoses upstream of the thermostat.

Excellent article and very interesting. The general information regarding block heaters and grill blocks is of course useful to all, but I'm wondering if there is a source of the operating modes and temperature transition charts for the Insight 1. I think I have been able to spot some transitions by watching the SGII water temp and the FCD, but I'm wondering if anyone has written down the complete and accurate tables?

Theres's some discussion in earlier pages regarding which portions of the HCHII grill to block first. We're in the temperate west coast region, and have had a very mild winter to date. The lawn is getting gangly, flowers and trees are sprouting, etcetera. No sign of snow, and not much on the local mountains, where something's been going on for the last few days...

Anyway, with the moderate temperatures I've only been grill blocking the lowest row on our bumper. Our block heater plug has just developed a break, so I rewired it with a new plug. In the process I pulled out the grill block.

Since the block heater cord is routing out through the lowest grill row, I decided to try blocking the upper grill row for a change, the openings just under the hood front edge.

My first impression is that it's at least equally effective during driving, but better at retaining heat if you're parked for a while, since it more effectively traps warm air in the engine bay.

My parents' new puppy decided it was time to remove the last 50% of lower grill blocking from my Gen3 Prius. Permanently.

Guess I'll have to use the 50% previously removed to redo the lowest two openings on my short commute for the summer. New blocking rule: 0% when visiting homes with puppies on the loose.

Tried some velcro strips for securing styrofoam pipe insulation. For a full width tube one strip towards each end works fine. I made a point of having close to 2" of overlap, and ensure the end of the strip tucks in behind the grill slat a bit. It's a little "friendlier" than zip ties I think, in that you can install/remove/reuse it easier. Here's the stuff I used:

http://www.leevalley.com/en/garden/page.aspx?p=45293&cat=2,43319,33283,45293

****in sweet article, may i ask if the hypermiling podcast will be back?

Hi dmafanp:

I guess there was not much uptake when we did them unfortunately. Kacey found greener pastures as did Manuel. We had some good stuff to talk about too ;)

Wayne