As the title says, I'm a little suspicious that the degree of assist is scaled to the battery charge. Certainly there's negligible or no assist when the charge is low, but that's not what I'm talking about.

If this is true, then it means it would be strategic to fuel efficiency to keep that charge up as high as it can go. Less fuel will be used to accelerate. But good luck trying to do this in the city.

 

I think the HCH2 tends to allow more IMA assist when there is a higher SOC in the battery.

Trying to get to (or maintain) a high SOC may be good for FE when you expend the SOC, but building the SOC through regen or forced regen ahead of this tends to be inefficient and wasteful.

I think some here would say it is optimimum to minimize both regen and IMA assist

 

SpartyBrutus nailed it pretty well. Regen and Assist are to be avoided as much as possible for maximum FE.

In other words, the assist affinity is affected by SoC and the higher it is the harder it is to prevent assist... and since the HCH-II pack is not deep enough it becomes very important to avoid a high SoC as much as a low. In my scale: 7-8 bars is high, 5 or less is low.

The strategy I recommend for folks who drive 100% city duty on an HCH-II is to manage their SoC so that it stays between 5 bars 7 bars. The ideal seems to be a six bar level and once we get to that level it is easy to sacrifice a bit of FE with a hidden regen at 50+%LOD to keep it there.

I recently demonstrated this to a News crew while pumping out city segments of 84 MPG (2.8 L/100K).

Cheers;

MSantos

 

Yup, when the SoC is totally full it wants to give up juice for the slightest excuse.

5 seems a level of homeostasis for my car--I regularly hit 7 (sometimes 8) bars on my commute, but it drops the charge back down to 5 very quickly. I hit 4 bars every once in a while, but for the most part it knows to stay above that point.

 

It's useless to me now. The battery charge is an unreliable measure. Just the other day I was "robbed" of 40% of the charge on one power-on cycle; The next cycle brought that missing 40% back. Perceived charge affects the IMA behaviour, even while it is based on a wrong measure.

 

Spinner, if you're seeing wild swings like that, expect a recal in the near future I've noticed the same thing leading up to the three recals I've had over the past two years.