Introduction and My Commute

[CRT1]

Hello all,

I am new to this site and to hypermiling. So far I am really impressed with this site and this community.

I'm a mechanical engineer, have loved cars my whole life, and I work in atmospheric research so this hypermiling business is right in my wheel-house. Surprised it took me so long to find it.

I live just outside Boston and commute into Cambridge (USA). My commute has three legs for a total of about 15 miles. The first 4 miles are suburban with light traffic, the second leg is about 9 miles of highway that varies from stop/go to steady movement in the 20-40 mph range depending on the day, the third leg is about 2 miles of city driving.

I drive a '11 Honda FIT Sport A/T 5S. Love the car but when I first got it I was unhappy with the ~28 mpg I was getting. Recently, I started to get buyers remorse so before looking at a trade-in I decided to try to max out the mileage.

The first tank of hypermiling, I upped my combined mileage to 33.6 mpg based on the gauge on the dash. I am most of the way through my second tank and it is reading 35.8 mpg! So far I have using buffers and better anticipation of lights, etc. and am still on that learning curve.

I am happy with the increase in FE, but one thing that I was not expecting is that I am showing up at my destination much more relaxed and happy. Before hypermiling, I was not aware how much sub-conscious energy I was expending just trying to get where I was going sooner. Since I am often in heavy traffic this would wear on me, but hypermiling frees me of that burden!

Questions:
- What is the maximum FE I can expect from this vehicle with moderate hypermiling technique? What about summer/winter differences?

- What are some other techniques I can use to save gas in this vehicle?

- Does it help to put the A/T in Neutral when coasting down a hill?

- What about turning off the engine at stop lights?

Thanks in advance for all of your advice!

-Chris

[ItsNotAboutTheMoney]

Originally Posted by CRT1

Hello all,

I am new to this site and to hypermiling. So far I am really impressed with this site and this community.

Welcome to CleanMPG.

I live just outside Boston and commute into Cambridge (USA). My commute has three legs for a total of about 15 miles. The first 4 miles are suburban with light traffic, the second leg is about 9 miles of highway that varies from stop/go to steady movement in the 20-40 mph range depending on the day, the third leg is about 2 miles of city driving.

I drive a '11 Honda FIT Sport A/T 5S. Love the car but when I first got it I was unhappy with the ~28 mpg I was getting. Recently, I started to get buyers remorse so before looking at a trade-in I decided to try to max out the mileage.

The first tank of hypermiling, I upped my combined mileage to 33.6 mpg based on the gauge on the dash. I am most of the way through my second tank and it is reading 35.8 mpg! So far I have using buffers and better anticipation of lights, etc. and am still on that learning curve.

Congratulations on your significant improvement! You're saving nearly 1/4 gallon per day. It's like a Prius driver going from 50mpg to 81.8mpg!

I am happy with the increase in FE, but one thing that I was not expecting is that I am showing up at my destination much more relaxed and happy. Before hypermiling, I was not aware how much sub-conscious energy I was expending just trying to get where I was going sooner. Since I am often in heavy traffic this would wear on me, but hypermiling frees me of that burden!

Isn't it great. This is because with buffering and anticipation (which you're using for light timing) you give yourself time and space to act instead of react. Everything becomes smoother and easier.

Questions:
- What is the maximum FE I can expect from this vehicle with moderate hypermiling technique? What about summer/winter differences?

<-- See the Mileage Logs

The best in there is 45mpg, but that's with only 6,000-odd miles. But there are a few over 40mpg.

- What are some other techniques I can use to save gas in this vehicle?

If you haven't done so already, please read the CleanMPG Primer. That links to other key articles on hypermiling, which will explain some of the different techniques.

There are a couple of techniques particular good for A/Ts.
- The most obvious one is Driving With Load, to keep steady rpms so the engine and transmission operate efficiently.
- There's also fake shifting, lifting off the gas to make the car think you've reached target speed so it will upshift earlier than during normal acceleration.
- You have paddle shifters on your Fit Sport so you can upshift early.

- Does it help to put the A/T in Neutral when coasting down a hill?

Almost always.

With the engine on and your foot off the gas:
- In gear: normal engine drag, but the car can use Deceleration Fuel Cut-Off (DFCO). DFCO allows the car to cut fuel to the engine while RPM is comfortably above idle. Once they drop below a certain level the car will idle.
- In neutral (NICE-on): it reduces engine drag, but the car will always idle.

As a rule, the benefit of NICE-on outweighs the DFCO because in gear because NICE-on makes use better use of momentum. You only coast in gear if you want to slow down faster than NICE-on would allow. You can use NICE-on both when going downhill and when decelerating, as part of Driving Without Brakes (DWB).

If you do find yourself needing to decelerate more rapidly you may be able to maximize DFCO time with early downshifts that keep the rpms up.

To know exactly what your car is doing you'd want an ODBII gauge like a ScanGauge.

- What about turning off the engine at stop lights?

Yes! There is an additional cost in restarting the engine but in fuel-injected cars it's quite small. So, while it depends on the vehicle it's usually worth turning the car off at a stop light as long as you'll be engine off for over 10 seconds. People will sometimes say that you'll wear out your starter, but again, with modern electronic ignitions it's not a problem.

Thanks in advance for all of your advice!

-Chris

You are very welcome. That is why Wayne and others created this site.

[TheStepChild]

Welcom to the forum!

[CRT1]

Thank you I.N.A.T.$.,

Thank you for the specific advice about my AT car. I have read the primer but some of the advice seems geared more to hybrids.

For example: You suggest Driving with Load and that makes a lot of sense to me to eliminate unwanted engine breaking. What about Pulse and Glide that I read about in the Primer? Is that more for hybrids or will it work with my car? Seems more complicated than DWL.

Also, I would like to add a personal victory: I was stuck in stoplight traffic for about 30 min yesterday, we were cued up for about 2 miles. The light would turn green and we move forward 20 car lengths and then stop. You know the drill.

I experimented with FAS and it worked amazingly well. Light would turn green, I would start the car put it in D, pulse, put it in N, FAS and glide to a stop and wait for the next green. My car was probably running only 3-4 minutes out of the 30 min and my ave dropped from 35.8 mpg to 35.6 and I made that back up on the second half of my commute! Simply awesome!

Thanks again for the help!

[abcdpeterson]

Originally Posted by CRT1

I am happy with the increase in FE, but one thing that I was not expecting is that I am showing up at my destination much more relaxed and happy. Before hypermiling, I was not aware how much sub-conscious energy I was expending just trying to get where I was going sooner. Since I am often in heavy traffic this would wear on me, but hypermiling frees me of that burden!

Well put! Same with me.

[ItsNotAboutTheMoney]

Originally Posted by CRT1

Thank you I.N.A.T.$.,

Thank you for the specific advice about my AT car. I have read the primer but some of the advice seems geared more to hybrids.

You're very welcome.

There is a wealth of specific advice for specific hybrids, simply because hybrids attract people interested in fuel economy. However, by applying hypermiling techniques regular ICE cars can do extremely well.

For example: You suggest Driving with Load and that makes a lot of sense to me to eliminate unwanted engine breaking. What about Pulse and Glide that I read about in the Primer? Is that more for hybrids or will it work with my car? Seems more complicated than DWL.

Pulse and glide works for cars with manual transmissions and some hybrids. I'm not sure about automated manual transmissions.

Pulse and glide doesn't work (or works in only a very limited way) for automatic transmissions because of the inefficiency of the transmission. "Slushboxes" are inefficient due to the lack of solid connection. To overcome some of the inefficiency a "lock" was added to the torque converter that gives a solid connection, but the lock is only used when you're in one of the higher gears at a fairly steady speed (depending on the transmission that can be down to 30 mph) in a limited power range. If the car thinks you need more power to accelerate or hold speed it will release the lock, and you're back to the lossy operation. As a result a pulse is inefficient.

On top of that, most automatic transmissions do not allow for a FAS as the transmission needs the engine running so the transmission is lubrication. So, the best you can do in a glide is an NICE-on and that's not as efficient as a FAS. In the case of Hondas you can usually FAS somewhat. Check your owner's manual for towing rules and look for the flat-towing rules. If you can't be flat-towed you shouldn't FAS, if you can, do not FAS above the speed indicated.

So, when driving you want the torque converter lock on. That's why Driving With Load is so useful for automatics. By maintaining a steady throttle position (or using only small variations) the transmission can remain locked. You can allow your speed to drop a little going uphill and as long as it doesn't drop too much the car will hold the lock and high gear. This is also why using cruise control is especially bad in automatics: instead of maintaining steady rpm the car maintains speed and will go in and out of lock. (Better cruise control systems will allow a little variation in speed to hold the lock better). Obviously, cruise control is less efficient on hills than on flat roads. By not using cruise control, even on my undulating commute I can maintain lock in our Civic surprisingly well, especially when there's no cars behind me.

How can I tell? When the lock is on your car acts like an MT with the rpm in any gear being proportional to speed. In my Civic, in top gear it's 1500 rpm at 45mph and 2000 at 60mph. As the lock comes on in top gear the rpm will suddenly change. Also, when the lock is on you'll see that a small change in pressure on the gas pedal doesn't effect rpm. (I actually noticed this "weird" behavior before I knew about torque converter lock).

Another point about the lock is that because you only get it in higher gears and speeds you want to get out of the lower gears more quickly than you would in a manual. So, acceleration in automatic is generally at a higher rpm. Drivers of normal automatics might use fake shifts, but you can paddle shift quickly through the gears. Not knowing the Fit, I don't know what rpm or shift points should be used.

In your lower-speed commute you might not be able to benefit as much from DWL, but it will help on longer highway journeys.

Also, I would like to add a personal victory: I was stuck in stoplight traffic for about 30 min yesterday, we were cued up for about 2 miles. The light would turn green and we move forward 20 car lengths and then stop. You know the drill.

I experimented with FAS and it worked amazingly well. Light would turn green, I would start the car put it in D, pulse, put it in N, FAS and glide to a stop and wait for the next green. My car was probably running only 3-4 minutes out of the 30 min and my ave dropped from 35.8 mpg to 35.6 and I made that back up on the second half of my commute! Simply awesome!

A warning: FAS is advanced technique that shouldn't be used without practice. You have limited assist on braking and may have limited assist on steering. You need to understand how the car behaves in a FAS in order to avoid putting yourself or others at risk.

If you're FASing a lot you need to watch out for the 12V battery, especially when you have to use your lights more. Compulsive P&Gers use trickle chargers to make sure their batteries are charged before they leave or buy deep cycle batteries that can better handle the work.

Anyway, I'm glad you're seeing immediate benefits from hypermiling and I hope this helps you further.

[CRT1]

I.N.A.T.$:

Thank you for the in depth description of the AT. I just converted from a MT '97 Civic so I am still learning about the AT. Your explanation is really helpful. I notice this behavior when I am driving, slush then lock when I accelerate a little harder. When in slush mode (not locked out) where is energy lost to? Heat in the gearbox?

A warning: FAS is advanced technique that shouldn't be used without practice. You have limited assist on braking and may have limited assist on steering. You need to understand how the car behaves in a FAS in order to avoid putting yourself or others at risk.

Yes, I was FASing at only about 5-10 mph tops in a very predictable situation. In this case I was rolling slowly looking at a red light, and trying to eliminate unnecessary ICE idle.

Steering assist is electric in the FIT so that seems unaffected by FAS. Brakes start to get really stiff after the 2nd or 3rd pump, so that is a huge risk, and puts higher speed FAS totally out of my comfort zone in this car.

Thanks again for the help!

[RedylC94]

Originally Posted by CRT1

When in slush mode (not locked out) where is energy lost to? Heat in the gearbox?

Yes (more specifically in the torque converter). Guess why automatics have cooling lines!

[CRT1]

I just polished off my third tank into this hypermiling business and it rang in at over 40 mpg! The on dash meter read 40.3 and I calculated 40.9 from the trip Odo/gas pumped.

Soooo much better than the ~28 mpg I was getting driving hard while gritting my teeth before I started hypermiling . . . . for my FE and my teeth!

This tank was mostly spent on a weekend trip to see my parents, so a lot more highway miles than my normal everyday, but still very encouraging. I think with a little more practice I can turn in 40+ regularly. Very cool. Thank you CleanMPG!

Cheers,
Chris

[basjoos]

Once you work up to the point of diminishing returns on maxing out your mpg's via hypermiling (driver improvements to improve your mileage), if you are handy with tools, you could also try ecomodding your car (hardware improvements to improve your mileage). Ecomods include adding a pushbutton engine kill switch for easier FAS, installing a vacuum reservoir tank to let you get more brake applications before losing power brakes while on FAS, adding battery capacity to avoid draining your batteries if you do lots of FAS at night, installing an engine block heater to get the engine up to operating temps faster, and myriads of aeromods to reduce aerodynamic drag, which can greatly improve your highway mileage.