a) What technique gives the HAH the best MPG when accelerating from a stop to cruise speeds?

One school of thought is to minimize the revs and cylinders. Another is to accelerate briskly enough that the IMA kicks in.

b) Same question as above but starting with a cold engine (before ECO mode is available).

Alan

 

I haven't figured this one out yet, either- haven't watched the mpg gage closely enough to make a determination.

My gut and spotty observations of the gage (non-navi, so I need to reset it often) tell me that the "minimize rpm and get on 3cylinders ASAP" is the way to go. 3 beats 6 every day of the week and twice on Sundays. Our animal is not like the HCH, in that the HCH leans on IMA a lot more than ours does to augment the small engine, so I'm not sure the HCH method of 'use IMA to accelerate" is completely valid for us. I think we should look at our setup more like a traditional 6 cylinder- keep the rpms down. But I don't know for sure. I don't know if any of the hypermiler dieties have enough drive time in the HAH to weigh in definitively on this.

With only 3 or 4 bars ('normal' SoC, at least for me), you need to accelerate REALLY hard to get IMA assist in this thing, especially on 6 cylinders, which means the engine is already tapped out, and running inefficiently.

Generally I've been accelerating a little slower than most traffic from stop, up to 30-35mph. Then I let up on the gas quickly to kick it into eco mode, and continue to accelerate on 3 from there, to extent possible.

I do the same on a cold engine, ecxept eco obviously doesn't kick on. I figure its best to ease the engine up when cold, not slam all 240 horses against the wall.

I'll try the jackrabbit vs tortise experiment as best as I can this week and post my observations. I really need to get an instantaneous gage...maybe Santa will get me one.

Anyone here looked at this and seen results one way or the other?

 

I second gonavy's analysis.
Gradual acceleration, cold or warm, yields better mpg. At some speeds IMA "volunteers" some assist, and I see some mpg benefit there. However, any time that I press the accelerator hard enough to "call" IMA, ECO goes off and the 6 cylinders and higher rpms outweigh the IMA benefit.
Bottom line: the lower I can keep the rpm and the sooner/longer I keep ECO on, the greater the mpg benefits.
Lewis

 

I think what I've found is this:

If you only need slight, gradual accelerations, then do it carefully and stay in eco mode.

But if you need to pack on some MPH, then give it at least 50% - 75% gas, come out of eco mode, get it over with and get up to speed quickly and get back into eco mode. During heavy acceleration like that, you'll almost always get an IMA boost too.

I seem to get better MPG that way.

 

I tried it both ways on a tank of fuel each. If I accelerate slowly (not tortoise speeds, but slow) I've been averaging 27 mpg. When I did the accelerate so you have half the IMA bars up until cruising speed, then I only got 23 mpg. Both using the same route to work and back. Relative temperature. Relative traffic. Same brand of fuel. Nothing unusual.

 

Good find. I'm trying the slow acceleration right now. I may get around to trying a tank full each way as well.

 

thanks!
My scangage just came in, so I hope to be abe to gather some details. If only I could export the data to trend.