Yeah, most of California is, including me. Supposedly this doesn't lower FE by more than 1 mpg, but I'd like to see how I do in some place like Arizona sometime, which I'm pretty sure has normal gas.

 

Hi CGameProgrammer:

___You have to let the E10 thing go unfortunately. I am stuck with it here in Chicago on each and every tank but the various techniques can overcome the 2 - 3% FE hit quite easily …

___Good Luck

___Wayne R. Gerdes

 

Hi Xcel,

very nice post. Thank you for all the information. However, from my point of view, I am not trying to achieve 80MPG. I understand where you come from and what your objectives are. However, some of the stuff that you describe is considered 'extreme' by me and I would prefer to ride a bike to work rather than subject myself to all the techniques that you describe.

My intent was to give guidelines to help people achieve better mileage not 80MPG. I have a few things that I want to try with the 2006 hybrid. I want to see what is the best way to start from a stop as this is what I encounter the most during my drives. Better understanding that will simply help everybody in getting better MPG in city driving. What I won't consider in my test is taking 5 minutes to reach 50km. While this will probably give the absolute maximum MPG, this is not what I am looking for.

In everything in life, most things follow a 'normal distribution' (the famous bell shaped distribution that we learned in statistics classes). Basically, when this is applied to our case (improving mileage), some will not be able to adapt their driving and they will always get low mileage. Some, will go to great lengths to squeeze an extra 0.1MPG. They will achieve 80MPG. Some just want to drive to work and get a reasonable MPG. This will be the vast majority that will be thrilled to get the EPA estimates. This last segment is the target audience for this thread.

Thanks,
Stephane.

 

Hi Stephane,

Short answer: about 3 bars of assist.

Long answer: I did some experiments where I measured fuel consumed to get up to speed with no assist vs. 50% assist and found that it was a wash (see the EV-mode thread for details). Since the amount of assist is tied to throttle position, which is also tied to fuel flow, using more assist also means using more gas. When using no assist and accelerating gradually, the fuel flow rate was lower, but it took longer to get up to speed. Using 50% assist and higher acceleration got me up to speed faster, but fuel flow was higher. I used about the same amount of gas in each case. However, these test results are based on the I-FCD, which is a rather coase instrument (each block represents ~5 mpg), so it's hard to tell. I also noticed that I can get up to speed with 3 bars of assist almost as fast as I can with 50%, so that's what I usually use. Also, as you have probably already noticed, the car is designed to give you assist even with gentle pressure on the throttle, so it's very difficult to accelerate with NO assist.

Of course, any assist you use is a loan against the battery that you need to pay back with regen (plus interest since it's not a 100% efficient process). I should clarify that when I coast to a light or stop sign, I usually don't coast all the way down to a complete stop without regen. Traffic behind me (plus my own impatience) usually prevents that, but I do try to turn as much of my kinetic energy into regen as possible. If you wait too long to apply your brakes and your regen goes to 100%, you are probably throwing away some of your kinetic energy. What I try to do is use just enough brake pressure to keep regen close to but below 100% so that almost all of my deceleration is coming from regen. This again means planning ahead and moving your slow-down point back from the light far enough that you don't need excessive braking to come to a stop in time.

Using no assist and a regen-less coast from top speed all the way down to zero will give you better mileage in many situations, but I think my technique is a good compromise for fitting into the normal traffic flow. When I'm the only car on the road, I go for the more aggressive technique.

 

Hi Slajenune:
___From what I see, 50 mpg seems pretty tough for most HCH-II pilots to date and if the thread is about being able to do better, I guess 50 mpg’s is OK? What does riding a bike have to do with hypermiling an HCH-II? If you cannot shift the car into N and turn off the key when there is absolutely no reason to have the cars ICE running, why bother worrying about owning a high FE automobile in the first place? Do you pour gas on the ground at the gas pump because it is easy to do? I think it’s a bad move but that is exactly what you are doing by having the car run when you are not moving forward.
___I don’t see anyone coming anywhere near 80 mpg so I don’t think we have to worry about that just yet … I will not stop pushing however because once an HCH-II owner finds out what is achievable (someone is going to nail a 70 - 80 mpg tank), then maybe they might strive to hit 55 - 60 mpg’s instead of just 45 as is the case for most HCH-II owners to date

___The best way to start is more then likely a no-assist technique if at all possible. As for the 5 minutes to 50 km/h comment, you only need to look at someone’s reset from the drive Trip A or B to see what horrible FE actually looks like. If an extra 2 - 3 minutes to fully warmed is not worth 50 - 55 mpg’s vs. 25 - 30 mpg’s, more power to you. You are talking about ½ the FE because of 2 to 3 minutes of haste. I think that 2 - 3 minutes for double the FE is worth each and every second myself.

___Then there is no need to explain EV/Glide, A/C off because your defrost capabilities drop by a fair margin if you do in fact need them, using 50% assist (bad idea for those trying to just meet the EPA estimates imho), and even thinking about P&G as that is a very advanced technique. Hitting the EPA combined can be achieved by following the speed limits and using a non-aggressive coast down to stop lights and signs with a > 10 minute trip distance in many cases.

___Good Luck

___Wayne R. Gerdes

 

Hi Wayne,

Great info for those who really want to push the envelope!

Well, I don't know if you can generalize that much. It really depends on the nature of the hills. If you're facing a steady 2000 foot climb over 10 miles, there's really no technique that I can think of that will help you Even the same hill can produce very different results depending on which direction you cross it (see this thread for my and CGameProgrammer's recent experience). However, I do agree that nice long down hill sections can really make a big difference, and proper driving technique can maximize that effect.

Agreed, which is why I'm stuck between a rock and a hard place given my reluctance to drop below 60 and the limited/no benefit to doing P&G from 60. Not to mention that tailgating is a favorite sport of many out here, even in the slow lane and P&G gives them no end of grief. So, since I'm pretty much boxed into holding a steady speed, I tend to get better mileage doing that with cruise control than I do manually maintaining speed. All that being said, I do take advantage of the cases where no one is behind me by turning off cruise, coasting/DWL up hills, etc., but it happens rarely enough that the effect on my tank mileage is minimal.

Definitely, this is part of the fun! It's a challenge to see how far out I can plan, then to see how well I can implement the plan. Makes you grit your teeth when a light turns red right before you get there or someone pulls out in front of you

I've tried this, but I get no immediate feedback of how much it's helping. With the key off, the trip mileage is not being tracked, so I don't get any credit for the coasting miles. I assume that the odometer must still be turning, so it's odd that the trip is not. This is with the key in the (I) position. If I turn it back to the (II) position after killing the ICE, the ICE comes back on, even in N. Also, on my commute I only have about 1 mile on either end that's non-freeway, so most of my warming up is done on the freeway.

 

Hi NASAgineer:
___Have you waited the appropriate time (1 + second) for the ICE to die off before going taking the Key from IG-I back to IG-II? Without the key in IG-III, IMA should never start that car back up if you are in Neutral. Let me know more about this because if IMA spins up the ICE while in Neutral and you are in IG-II, that is something I have never heard of or would have expected. That means it would start you car while sitting in the drive in N when just booting up the electronics as well and I do not think the HCH-II does that? Without the ability to perform a real FAS when and where appropriate, the HCH-II is at a severe disadvantage to the 03 - 05’s.

___Good Luck

___Wayne R. Gerdes

 

Generally, a "shot across the bow" means - you've been warned, stop going where you're going, change course!

Is that what you meant? Care to elaborate?

 

Well, you're only doubling the FE for those 2-3 minute segments. For someone with a 30 minute commute each way, you're only talking about 55 mpg vs. 52 mpg for the trip each way.
For longer commutes, it's even less. For some people, it's not worth it to go through all those key on/off gyrations just to get 3 mpg better.

 

I think I was waiting a couple of seconds, but I'll try it again to see if waiting longer prevents this. I assume it only does this if the car is in motion, maybe to protect the CVT?

Do you turn the key off with the CVT in N or D? I was shifting to N, then turning the key off.