Quote:
Originally Posted by roflwaffle
It'sa function of how engines operate. Engine efficiency, generally speaking, is relatively poor at lower loads, and tends to increase w/ higher loads. If the engine is making power, and we add power from an electric motor, then engine load will drop and efficiency will probably drop too. There are situations, depending on engine load/speed where engine efficiency won't drop much or at all, but especially at lower speeds, outside of when the vehicle is accelerating, using an electric will probably decrease engine efficiency.
On the flip side, since low load is where an engine operates inefficiently, and this corresponds to low power, w/ a manual trans and a sufficiently powerful motor/battery combo, we can run on just the electric motor's output and only use the engine where it's efficiency is maximized.
Course, like I mentioned before, this brings up another problem, namely stretching a motor's power output over whatever gearing the rear end has, and since optimizing engine efficiency tends to include taller gearing, we may end up having motor power peak at a speed much too high to be useful for low speed/low load operation. There are exceptions, for instance I have an old Mercedes that tops out at ~76mph or something, so peak power at ~38mph is fine, but for other vehicles with taller rear ends, especially larger ones, having peak power at ~50-70mph isn't desirable in the context of using a hybrid conversion in a cost efficient manner. Gearing the motor up would help, but that introduces another set of problems. If ya want specifics LMK.
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Yes, and testing my combination of engine, gearing, mph, etc. will determine any improvements at a given speed.
My particular interest is electric motor only, low speed, stop and go, which will require gearing down an electric motor, and the ability to remove it from the drivetrain.
Thanks