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Can someone answer or point me to a link that might answer my questions?

If I do some ball park math, my first segment is really pulling down my commute average. With my engine block heater (EBH), I have improved my first segment, but are there any specific driving techniques associated with the Prius that might help me even more? Do I just have to grin and bear it until the engine warms up?

Hi Chris:

___Besides an ICE block heater, an oil dipstick or pan heater would help as well as a Radiator and Engine bay block will help as well but not that much. Because you do not want to shut down the system, will the Prius II’s ICE stay shut down by shifting into N while you are in a slight regen mode? If so, this would help bring your temps up in a Warm-up P&G if it works? The Warm up would take longer this way however? Cold temperature warm up in a Prius II is a killer :(

___Good Luck

___Wayne

I'm sure you've seen some of our recent discussions at PriusChat about blocking the upper and lower grill... this has a dramatic impact, actually. Realize that it's not b/c we're stopping the air flow through the radiator so much as b/c we're reducing the air flow through the engine compartment. That little aluminum ICE cools off quickly esp. when gliding, but also at any stop.

Further, I've added some fiberglass insulation around the ICE...can't say with certainty that it helps, but it cost little and I do suspect it's maintaining the ICE temp a bit when I'm shut down dropping off kids and such....it may also help the EBH get the ICE temp a little higher just by holding in some of the heat.

Other tips w/ Prius....set the temp to "Max cold" vent fan at the lowest speed (AC and Auto setting off of course)...at least for the first 5 minutes. You won't get much heat anyway during that time and the reduction in cold air being forced around the ICE to heat it up helps maintain the temp better. Someone else at PC posted a graph some Japanese guys created showing how much variability there was in ICE temp depending upon the temp setting during the initial warm up. Once the ICE is sustaining 170 degrees or so you should be able to add some heat (I use 69 degrees) without a lot of impact on ICE temp unless you'll have a prolonged stop (more than 5 minutes?)

Finally, and I'm not positive this is the best idea, I tend to try to encourage the ICE to run a little more during the first 5 min. Small hills I usually glide down I'll just push the rpms above 1200 to keep the ICE spinning...I don't think I'm doing the car or my mileage any favors by gliding and letting the temp drop down before fully warmed up since I'll just have to rewarm it latter. This isn't something dramatic, but rather just a subtle thing where I won't allow a short glide that, in warm weather, I might take advantage of.

A couple more little things I'm sure you've considered....use Mobil 1 or another synthetic oil for the possible advantage of lower viscosity. Check the tire pressures more often in cold weather since they'll go down w/ the temp....likewise if you have a warm up they can get higher than you want.

I am pretty good about checking tires and I am going to switch to synthetic 5w-30 at my first oil change in 400 miles and not the 0w-20. It really doesn't get that cold here and I will stick with mfg recommendations on this one.

Even at 28F and no grill block, I am able to get the car to P&G without "too much" effort. Read below.

Excuse my explanation in the following paragraphs. My latest observation / question:

A given; using the block heater has helped my first segment mpg on the consumption screen. I really should just invest in a SGII so that I would know for sure rather than guessing with the not terribly handy consumption screen (if it were mpg vs. mile rather than time it would be much handier for me). I have limited data, as I just installed my block heater about two weeks ago.

Continuing; I have picked roads with speed limits at or near 35 mph for my commute to and from work. I normally pulse up to 36 mph so that the engine can shut down during my glides. Sometimes pulsing up to 36 mph may not be convenient (sp?), especially if it is a 25 mph speed limit, there is traffic, red lights, etc. Generally, I have always been able to get around this by being able to pulse above 35 mph or deal with an idling engine for a short time as I am regen"ing" to a stop (i.e anticipating traffic by slowing without stopping). The car will not glide at this point because the engine wants to run and I fight with it to go the longest distance I can until I can pulse again above 35 mph.

Normally, in cold weather, I could finally get the engine to shut off at speeds less that 35 mph during a slower pulse and glide after about traveling 14 miles of the 18 to work. However, a few miles into my trip to work the other day, I started to pulse and I had to stop for unexpected traffic and a red light. The engine ran for a few seconds at the light and eventually shutoff. From there, for the rest of my commute, I was able to get the car to glide at speeds less than 35 mph. Rather than rolling all the way to a fresh red light, I pressed the accelerator hard enough to just start the engine and then came to a stop. The engine ran and shut off as normal. From there, I was able to pulse and glide at slower speeds. It is almost like I have to let the engine shut off on its own for it to go into the next stage of operation where you can pulse and glide at any speed pending SOC.

Does that make any sense?

If I am to use a grill block, the only way I see it helping me would be for it to somehow increase my impg during a pulse so that I don't have to glide so far to get high FE. If I pulse for 0.1 miles at 20 impg, I have to glide 0.4 miles to acheive 100 mpg. If I could increase my impg to 25, then I would only have to glide 0.3 miles to get the same 100 mpg. Like I said, at 28F, I was able to get the car to P&G at "almost" any speed as I described above all the way to work for about 45 minutes. I use a slower pulse in the winter time so that the engine runs longer to keep it warmer. I start with a block heater on one half of my commute.

I think there is something to allowing the car to shut off on it's own to get to the next stage of hybrid operation.

But, do you not have an EV button yet? Sounds like you don't but could certainly use one for some of the situations you describe....those low speed 'need to slow for a stop' situations I use the EV button as soon as I realize I need to slow for a stop but my speed is under 35mph (making it hard to get into an ICE-off glide).

I still think you'd find the grill block, at least the top if you don't have a way to monitor the MG2 Inverter temp, helpful.

I also think you should invest in the CAN-View...you'll find the data you obtain very valueble in eaking even more distance per drop of fuel than you already do.

As soon as I try to describe a one or two time phenomenon in my previous post, sure enough, I fought with the car most of my commute home to get it to go into stealth mode. :o

With instances like tonight, I can see the potential for keeping the engine compartment temperature slightly elevated.

I'm fighting with the same issues. It seems to take forever for the car to get into the "normal" mode of operation where the ICE will shut off during a glide. I usually roll up to a stop sign only to realize that she's still idling away to get warm. Today I installed an upper grille block of squashed pipe insulation. I have another 6 feet of the stuff but I don't know if I will use it for anything since I have no way of monitoring inverter temps.

It's somewhat amazing that this car is giving me even my 51-54mpg given how much of an impact cold weather has on the hybrid system.

Hi Efusco and Tim:

___Will placing her into N while under regen (below 41 mph of course) keep the ICE off up to the next stop no matter the coolant temps and primary to secondary O2 voltage differentials?

___Good Luck

___Wayne

I'll have to install the ScanGauge to test that one out. At the moment it's a bit tough to tell when the engine running while in regen.

I just figured out what I absolutely have to do to this car: EV button. The first mile of my commute is down-hill, and there's no reason for the engine to run since the car barely needs any power to get moving. If I could delay engine start until slightly before I need it, I bet I would save quite a bit of fuel in the morning.

Hi Tim:

___The following should help with that last request …

Electric Only Mode (http://www.coastaletech.com/electric_only_mode.htm) w/ cancellation or activation via CC stalk vs. the std. EV On/Off button. I bet PC has a lot of discussion about this one.

___Good Luck

___Wayne

Yup, that's what I was looking at. The trigger hath been pulled.