I pulled the following off of a Car and Driver review:

"Regenerative braking is the big payoff of hybrids, the ability to recapture the energy of vehicle motion that's ordinarily wasted as heat to the brakes. Feeding that "saved" energy back into forward motion accounts for 60 percent of the Accord's mileage gain in city and 38 percent in highway operation, Honda says. But there are many small losses besides braking, and Honda has attacked them, too.
Why run the engine at idle? The Accord doesn't, accounting for 25 percent of its improvement in city mpg.

Why fuel all six cylinders when three would be enough for much of your trip? The Accord doesn't, for another 15 percent of its city increase, 57 percent highway."


After reading this, I feel that I should be slightly punching it from a stop, enough to get the assist working before trying to maintain ECO mode. My strategy so far has been to accelerate as slowly as possible. The current tank I'm running is averaging 30.7 mpg but i have around 50% highway driving on it. Any thoughts???

 

It's nice to be able to recover energy, BUT...

I don't buy the claim that IMA accounts for anywhere near 60% city savings. I think that autostop and eco mode have a lot more to do with it for all but the biggest leadfoots.

- 3 beats 6 every time, no matter how you cut it. Rely on VCM, not IMA for your savings. Our IMA is really just a strange supercharger, when you think about it.

- You would need to maintain 5 or 6 bars constantly to enable any IMA assist in all but the fastest starts. That's doable with a lot of braking. The question is whether even that level will enable IMA to kick on early enough, and whether IMA is strong enough to make up for the extra ICE losses incurred with the fast start. I believe that IMA is not big enough to make it up (6% assist @ max ICE power, probalby 10-12% for normal conditions). Even if it were, energy still got thrown out the window during a hard acceleration.

An ICE is never never never efficient when its gunned/floored/opened up/whatever. Peak efficiency is between 1/3 and 2/3 loaded- right where a reasonably slow acceleration takes you. (I have a scangage that shows me loading now... ) Doubling the engine load from 50 to 100% more than doubles fuel consumption. So getting to the same speed at full throttle always uses more fuel than doing do at 1/2 throttle, even if it takes 1/2 the time to get there. And the energy put back in by regen only cares about what the speed at the start of decelleration was, not how fast you got there. So you threw away energy just to get up to speed in less time.

Having said that, please try it out and let us know your results! The HAH is a lone duck in the pond, and has nowhere near the amount of combined experience as the HCH.

My suspicion is that 30-32 in town is about the best that mortal drivers like us will do without FAS. No matter what, there are 6 thirsty cylinders drinking gas every time the ICE is started up, and every time you coast in N. I believe its best to make those front 3 work as little as possible, then put them to bed every chance you get.

 

After over 20,000 miles, my experience matches gonavy's. I do see some IMA benefit in stop and go at speeds under 40. IMA will "volunteer" (I don't have to "punch" the accelerator to "call" IMA into play), and ECO will stay on, the best of both worlds--3 cyl plus battery assist. And Autostop is very beneficial, also, as well as being quiet....

My daily commute (80 miles round trip) includes a couple of hills. Several thousand miles ago, I tried IMA for the hills--ECO goes off, 6 cylinders go on, rpm goes up, and IMA helps; I learned to feather the accelerator to keep IMA on for the 30 seconds or so of ascent, maintaining near limit speeds of 60 mph. Same hill with ECO strategy: keep ECO on as long as possible, driving with load, slowing to 45 by the hill crest, eventually using 6 cyl but no IMA, keeping rpms as low as possible. Always better mpg with the ECO strategy, but not always possible with a dump truck on my bumper.
Lewis

 

Anyone know the best way to get our batteries fully charged? I can never seem to get it charged above 4 bars except on a few trips where it has gone to fully charge. Seems to charge best on certain routes than others even in stop and go traffic.

 

drive up a mountain, coast down.

 

Other than that considering there are no mountains around here? It's too bad we can't plug our cars in to get a full charge like the Prius.

 

Have someone tow you for a while? ;-)

 

Four bars is my normal top. I've seen 6 bars once, after service for a check engine light; batt level was at 3 bars when I took it in. Asked the tech if he used a charger to get 6 (he didn't know how many "bars" there were; it was his first hybrid service); he said, "no, I just revved the engine...."
IMA was very active at 6 bars, speeds under 40, but within 2 miles of city driving, it was down to 4 bars.
Lewis

 

Thank you guys for the advice. I should have said 50% to 70% acceleration on the pedal instead of "slightly punch". I have an 8 mile commute all city to work and the thing that seems to be bringing me down to 25 is that the system doesn't work until it's warmed up. I test drove to work when the car was warmed up and I was at 31.5 round trip, I was using the slow acceleration method as much as possible and keeping the eco light on.

 

lots of early braking. Start braking early enough so you get all the bars lit, but no harder than that. This way you'll maximize the time that you are recharging. But for better overall FE, start coasting even earlier and use no brakes. Put it in Neutral if you don't think you'll necessarily be stopping (timing a light, etc).

DO NOT WORRY ABOUT ONLY HAVING 3-4 BARS!!! Completely normal. Any system that is being constantly partially replenished and depleted will average out to around 1/2.