Has anyone determined if there is a technique for braking to maximize the amount of kinetic energy put toward regenerative braking versus going to the regular old brakes? That is, given that you know you have a stoplight coming up some distance ahead, is it best to coast a long time and then brake harder near the end, or to "ride the brakes" for a longer time? I can watch the green bars that indicate "charging" but I wonder if it is best to max out the green bars for some of the time, or to avoid maxing them out to get longer time duration at not-quite- maximum on the charging display.

It seems that you'd want the regular old brakes to do the least amount of work (within the realm of safety, of course!), so that the battery gets maximum recharge.

 

It's possible to tap the brakes very lightly so it charges without braking.

 

You can just touch the brakes to get almost all bars lit but be losing speed at a negligibly faster rate than by just coasting- almost no friction braking. So its almost as long as just coasting but with more charging.

By 'driving without brakes' or basically coasting as long and as often as possible your FE can stay very high. I used to shift into neutral to coast; I have found there to be very little change in FE doing that vs coasting in gear. Neutral keeps the engine at idle fuel consumption; coasting with the foot off shuts off the injectors. You don't coast as far in gear but are effectively using zero fuel.

 

I found this in a new article on Hybridcars.com about using capacitors and batteries in the hybrid system. It appears to support the idea that we should be braking slowly rather than hard to stop quick.

If you push a battery too far, it can overheat. Therefore, there are limits to how much power a battery can handle when charging. Think of a battery as a huge tank with a thin hose connected to it. The tank can hold a lot of water, but filling and draining it takes a long time compared to that small air balloon, which can fill and drain quickly.

 

How does that work? How can the car shut off its injectors? If the fuel injectors quit injecting fuel wouldn't the engine die? If that were the case, wouldn't the rpms drop to zero. When I coast downhill with foot off and no cruise control, the rpm are still around 1500rpm...maybe i'm missing something.

 

I have to admit, I got this information from here via a 3rd party. But I verified the results with my scanner.

The engine keeps turning because the car is in motion- the transmission, even an automatic, keeps the engine turning over until a certain point. Then it has to idle on its own so that it doesn't die- injectors open back up and the idle air motor forces air through.

If you have access to a OBD scanner, you can see this. Foot off gas in gear drops fuel consumption to zero and fuel economy pegs out. This does not happen if you coast in neutral. FE may still max out, but fuel consumption will be nonzero.

I am not entirely knowledgeable in the details- it was a surprise to me when I learned it too. And it may not be true for all vehicles.

https://www.greenhybrid.com/discuss/...navy+injectors