I have an '05 HCH. I live in a very hilly area, and my MPG averages about 38-42. I notice my MPG can be 50MPG or better when I travel away from home on flat terrain. My question... Is it possible to alter the HCH's computer in order to get MORE assist from the electric motor when accelerating or going up hills? If so, who can do this? If not, anyone know of another hybrid which can be tinkered with?

More assist on hills is really not the answer. The less assist you use the less you will have to regen and your mpg will be better for it. I live in a very hilly area, drive an 05 HCH, and get 55+ mpg on my average commute which is about 50 miles round trip. I get over 60 mpg on long interstate trips. I have done no mods to the car other than normal maintenance, switching to 100% synthetic oil, upping my tire pressure, and slowing down.

Try reading this article Beating the EPA - The Why’s and how to Hypermile and see if you can see some things that you can do differently to increase your mpg.

~H~
Don't Click Here!

Thanks for your reply and the excellent link.

I'm still a beginner at hypermiling, but the link has many suggestions I plan to try. But for the sake of this discussion, I'd like to focus on the hills.

I have a 20 mile commute that requires me to climb over several very steep hills. The worst of these is a 425 foot climb in less than a mile (over 10% grade I believe); there are several others that exceed 400 foot climbs, with steep grades exceeding 6%. It is not possible to climb these hills at a steady speed (that is, without deccelerating) without getting an instant MPG of 20 or less.

I know I will hear suggestions to avoid these hills, but really it's not practical without adding an additional 10 miles or more to my commute. I could be a slave to my instant MPG by driving 50% more to see an increase of 10-20% in efficiency. Using more gas to save MPG doesn't make sense.

So, I ask again. Anyone know how I can unlock the power of the IMA when I need it for hill climbing?

I mean no dis-respect in my answer but I figure you need a blunt answer first so that you can begin to frame the power of the IMA architecture in a proper context.

Since you are just beginning your journey into hypermiling, I will offer the following assertions (anyone else can comment if you please):

1- Please look at the IMA architecture as an energy recovery system. That is it, no more no less.
2- The potential energy used and stored by the IMA system is 100% derived from the gasoline in your tank, and is as finite as it is VERY expensive.
3- For propulsion purposes, the IMA system's best contribution is that of a low RPM high torque power source that is most useful when accelerating from a stop or lower speed.
4- The IMA system is of diminished value for prolonged mountainous commuting particularly in the climbing portions. A good hypermiler will minimize its use if at all possible in order to come close to unlocking its potential.

The governing software that defines the behavioral and operational parameters is Honda proprietary and closed. So unless someone does some reverse engineering on it and publishes their work for free, it is very unlikely you'll ever get to change it beyond what you got to work with now.


Now, for the simplest answer to your question. To unlock the "power of the IMA" you have to look no further than the person you see every morning in the mirror. The best way to do it, is to tap the best HCH pilots who have been tirelessly dedicated to making the most of the architecture.

If you are still interested, please follow the trail to the one and only hypermiling headquarters.

Cheers;

MSantos

This is all counter-intuitive. If the IMA is an energy recovery system, why should I avoid using MY recovered energy? If I climb a hill and have 65% battery power when I reach the top, I’ve wasted gas by not using stored/recovered power.

I mean no dis-respect in my reply, but I’m not on a quest for inner peace. I use a machine to get from point A to point B, and I’m exploring ways I might tweak the operation of the machine. The condescending tone that I haven't attained your "tirelessly dedicated" level of driving enlightenment... Not helpful.

You are new here and I think I should mention the msantos is one of the leading experts here on the HCH and has been known to be very helpful both here and on other forums. He really does know of what he speaks and is not being condescending. Just because you don't like the answer doesn't make it incorrect.

~H~
Don't Click Here!

Sorry billh;

Like I said, I meant no disrespect particularly since you provided the following reference in your previous post:

...which indicated the possibility of some interest in hypermiling. My apologies for reading you wrong.
On a side note, had you not mentioned it I would not have lead my answer the way I did. Mainly because hypermiling is about a properly setup vehicle and the understanding and use of fuel efficient techniques in order to beat the EPA rating for you car.

In any case I really hope you find what you are looking for and I also wish you good luck tweaking "the operation of the machine".

Cheers;

MSantos

Sorry too for reading too much into this.

Sounds like Honda doesn't allow me to change the software settings to get more out of electric portion of my hybrid. I think that's a shame. If others disagree, that's fine.

Anyway, as noted, I'm new here and I've seen a lot of useful information posted by a lot of dedicated individuals. I'll stick around and hopefully learn more.

msantos:

I think there is something to billh's question. There are certainly situations I've run into where I know the terrain and I know the IMA is not going to work completely in my favor because it does not forsee the future.

Here's a scenario:

In San Jose, we're about 25-30 miles from the beach over in Santa Cruz. Between the two cities is a mountain range. The 4 lane highway over the mountains climbs about 1500 feet before a long down hill run to the ocean. On the downhill run, the regen from coasting usually tops off the battery after about 1/3 of the descent. After that, there's no more regenerative braking to slow you down for the 40 mph winding turns.

Inevitably when I reach the summit, the IMA has been too protective of the SOC and i've still got 5-6 bars (HCHII). Since I know I'll more than recharge the battery on the downhill run, I'd really like to use nearly all of my battery on the climb. Without knowing the terrain, the IMA just has no way to figure this out. To maximize my FE on this route, I'd love to be able to push a button at the base of the climb that tells the IMA that its okay to keep assisting on long climbs (I think we've all seen it back off the assist on a climb after about 10-20 seconds of steady state climbing). The climb mode would also postpone the forced regen. By the time I arrive at the beach, the battery would by full again.

I don't honestly think very many people would want a button like this, but a few that want to more closely manage energy flow would probably see the advantage. Perhaps this is sort of what billh had in mind.

-dan

Not sure tinkering with computer is required. In my manual '05, I just mash the accel to the floor and get max electric assist. Depletes quickly, though, and the next several hills are all gasoline.