Why is MID Always Optimistic?

[Moviemike]

Originally Posted by Uriel

I guess I had my Drive Without Brakes (DWB) hat on when I posted that. Realistically, brakes are frequently essential and not stopping is not an option.

I do sometimes wonder about how efficient a super economy mode would be, where all battery charge came directly from braking, deceleration or coasting downhill and never from engine load. Probably would make the car much less pleasant to drive I think.

Well sure!
An improvement I'd very much like for the I2 would be a switch that would let you disconnect from the battery and operate with ICE only. I would use it when climbing long hills, where currently forced re-gen requires the engine to charge the battery while still coping with the big hill. With such an option I'd run on engine only up the hill. Then I'd reconnect the battery system and re-charge, as now, with forced re-gen, brake re-gen, or downhill coasting ....giving a kind of "engine braking" safety effect. I think doing this will greatly increase I2 mpg in mountainous conditions, while increasing safety by making more power available for the up grade.

[Zwolfe]

You can overcome the recharge going up hills by applying more throttle. Well, of course ... d'oh, Zwolfe?

What I mean is that the battery charge needle will gradually go toward neutral (no charge, no assist) with the more throttle you apply. It will go to neutral with no drag from the IMA system if you apply enough throttle.

I noticed this from driving up mountains here in WV. Just trying to maintain speed pushes the IMA system to neutral until you crest the mountain (where regen is established once more).

I should had noticed this months prior due to a big hill near where I live. My wife drives up this hill and rarely ever has regen. I noticed that whenever I tried to drive up it, I'd get regen. Apparently, she just uses more throttle than I do.

Of course, you're burning more gasoline getting rid of the IMA drag going up hills, etc., unless the system is charged well enough prior to ascent.

I do wish a super-econ mode existed as you described, Moviemike.

[Uriel]

And with paddle shifters you can control uphill Regen without increasing speed. Stick in S, select high gear and open throttle as much as needed.

It will still Regen at the top though. Fine if you've got a peak and downhill next but will still kill mpg if it's a plateaux.

Uphill Regen is preventable so long as you keep rpm high. With paddle shifters in S mode shift down until the Speedo turns green at the bottom of the hill and stay relatively light on the throttle. I think just having it in S helps even without the shifters.

If you're in more of a hypermiling mood, holding the Speedo in green or turquoise is a good driving with load (DWL) guide in D. You'll slow down but running out of juice is unlikely.

[Moviemike]

Originally Posted by Zwolfe

.....What I mean is that the battery charge needle will gradually go toward neutral (no charge, no assist) with the more throttle you apply. It will go to neutral with no drag from the IMA system if you apply enough throttle........

Really?? Hadn't noticed anything like that before. I'll give it a try, and let you know.

We have some really big hills here on the Or. coast. One which is near-by is a 6% grade and 2.5 miles long. I've tried many different things in search of the best way get up these big hills with least use of gasoline and a goal of maintaining at least 45 mph.

...A hill I'm thinking about has a passing lane, 60 mph is ususal cruising speed prior to the hill. Most people (especially trucks and bus -like moble homes) will slow on the long up grade. What I"ve found works best (so far), is to hit the bottom of the hill at 60-65 mph with as much battery charge as I can muster. Then increase throttle as speed declines with the up grade. I don't aim to maintain 60 mph but only to slow the decline in speed due to the hill. When I hit around 52 mph I shift into S. This increases rpm to around 4200 rpm and increases asst use, and changes the speedo from turquoise / purple to green. Shortly there after asst suddenly drops away and changes to chg as forced regen kicks in to protect the 2/3 depleted battery. Speed will decline and I'll press the throttle harder to maintain 45-42 mph and 3200-3500 rpm. I know that 50-55 mph is within the car's capabiility, but I'm not wanting to run the engine in the 5k rpm range for the 3-6 minutes that it will take to reach the top of the hill.

(I've played around with the paddle shifters...on flat roads. I've found that I can't do any better than S mode without a whole lot of effort. Found it easier to not sweat it and just use S instead.)

It would be ideal, for me, for Honda engieers to address this issue and come out with a super eco model for enthusiasts such as I; who seek to squeeze as much mpg as possible from the IMA system. (Like twisting a wet towel to get as much water out of it as possible )

[Moviemike]

Originally Posted by Zwolfe

You can overcome the recharge going up hills by applying more throttle. Well, of course ... d'oh, Zwolfe?

What I mean is that the battery charge needle will gradually go toward neutral (no charge, no assist) with the more throttle you apply. It will go to neutral with no drag from the IMA system if you apply enough throttle.

I noticed this from driving up mountains here in WV. Just trying to maintain speed pushes the IMA system to neutral until you crest the mountain (where regen is established once more).....

I took a look at this earlier today and I suspect that doing this just leads to longer or more battery recharging after you've crested the hill. Not certain though, but here is what I found.

1st hill. It is of moderate length but steep. On most days I can get to the top without forced regen if I have a strong enough battery charge and plenty of speed at the bottom. Today I had speed but weaker battery at bottom. Half way up forced regen kicked in. I stayed in D with Econ on, shifted the MID to energy flow screen, and gave it lots of throttle. The needle went from Chg to Asst, the speedo to purple. I let up slightly on the throttle, and the needle went back to Chg. I then pressed the throttle harder but the needle stayed in Chg. There was plenty of hill climbing power, and speed at the top. After the top, and during the following downgrade much more regen was needed to recharge the battery. ...I figure a net increase in amount of gasoline was needed to climb this hill.

2nd hill; This one is shorter but not as steep, the approach to the hill is such that I ordinarily need a short period of regen to get to the top. Today, after regen kicked in, I gently increased throttle while focusing on the needle and was able to get the needle to the mid point. At that point I was at the top of the hill and had to stop for a traffic light. After the light, is my usual recharge down grade followed by a gentle down slope where I ususally can get a good ev run. Today I couldn't clearly tell if additional regen was needed.

On the 1st hill I had the energy flow screen displayed. It appears that forced regen kicks in when battery charge level decreased to 1/3 of total capacity. Increasing throttle pressure, just after regen kicks in, just seems to dig deeper into the remaining stored power in the battery. Untill a safety something is encountered preventing further battery discharge and forcing the recharge process.

Regardless, it looks like applying more throttle may briefly delay recharge, but will do so at the cost of decreased mpg, and with the benefit of more speed while hill climbing. .....thanks very much for the suggestion