Thanks to the good folks (and particularly the parents) on CC, I am now plugging in my PHEV as often as possible (competing with my wife’s EV). I had almost NEVER plugged in my PHEVs, but based on previous threads here, I realized that was silly.
Unfortunately (?), I am now obsessed with getting as much mileage from my PHEV as I can, and I need you to bring me down! Gas prices in the Bay Area are sky-high, so this is now a cost savings issue, in addition to a climate issue. But it also makes driving a bit more fun, almost like a game, to see what is the best MPG I can get.
We live in a particularly hilly part of the Bay Area. It’s great when you go downhill where you lose essentially no EV miles OR when you’re in city traffic that is stop-and-go where regenerative braking helps keep up the EV miles.
A few questions to get your thoughts on how to maximize PHEV efficiency:
My car has 3 modes: EV only, hybrid only, and automatic (which, from what I can tell, lets the car automatically switch back and forth between EV only and hybrid only). Based on my limited research, the basic rule of thumb is to use EV only for city or stop-and-go driving. When on freeways/highways, use hybrid. Is that right, as a general matter?
How do you deal with hills? As mentioned, going downhill costs essentially no EV miles. However, going uphill (and we have some steep hills in the Bay Area) QUICKLY consumes EV miles. How do you handle this?
This is probably a dumb question, but I am not an engineer and despise physics. I have a very basic question: why do PHEVs (and I guess EVs) use regenerative braking for energy generation? Wouldn’t it be easier to use the wheels turning as dynamos to generate electricity rather than wearing down the brake pads? Given my newfound obsession in driving efficiently, I find myself using the brakes quite often, especially going downhill. Before, I would put the car in a lower gear to allow the engine to serve as the brake.
Are there any other suggestions you have to drive a PHEV more efficiently.
Have I gone off the deep end in being so obsessed with mileage?!
If the distance between recharging is within EV range, you can use it in EV mode for the entire trip (or automatic mode if EV mode is not powerful enough for highway driving). However, if you have (for example) a trip too long to be within EV range, but with a distinct city portion after a high speed highway portion, then it can make sense to use hybrid (non-EV) mode during the high speed highway portion before reaching the city portion, when you change it to EV mode.
Mostly, you let the car deal with it. Uphill consumes more energy than downhill. EVs and hybrids do allow recovering some of the energy going downhill.
Thanks for the response. However, I’m not sure what you mean. I am asking why the wheels turning, which seems like a no-brainer to generate power, is better than using the heat from the brakes to do the same.
I am going to say the exact same thing (as far as I can tell) as @ucbalumnus but using my own words.
The difference between an electric motor and an electric generator is timing. On a modern electric or hybrid car, the timing is done by a computer, which is capable of changing the timing very easily and very quickly. This means that the electric engine(s) that you have in your car is both an electric engine and an electric generator. It does either one equally well.
When you apply your brake petal, you are telling the computer that runs your car that you want to slow down. If you want to slow down only a little bit (hit the brake lightly), and assuming that the battery is not already 100% fully charged, it will slow you down a little bit by using the electric generator (aka the electric engine) to both slow down the car and also generate electricity. If you push the brake petal harder and therefore ask to slow down more quickly, only then will it use the actual brakes to slow the car.
This means that there is a fundamental difference between driving my wife’s Prius or your PHEV versus driving my ICE car. If I push the brake lightly in my ICE based car, it uses the normal brakes and wears them down. If you push the brake petal lightly in your PHEV, then the car only uses the electric engine, in electric generator mode, to slow down the car and recharge the battery.
Yes, this both helps your fuel efficiency and also helps to prolong the life of your brakes. This is definitely a significant win-win if you are driving either a hybrid, EV, or PHEV.
