In hybrid vehicles, I know the battery can be recharged using regenerative braking, but I also see them sometimes recharge the battery using the engine directly. Why would they do this? It seems like it would be better to use the motor just to move the vehicle. Why go gas -> engine -> battery -> wheels?
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So there are basically 2 kinds of hybrid vehicle, “series” and “parallel” layouts.
In a parallel layout both the ICE (Gas) engine and the electric motor can drive the car.
In a series layout only the electric motor actually drives the car and the gas engine just charges the batteries, it’s basically a generator.
The reason being that gas engines aren’t “universally” efficient, meaning if Honda says the Civic gets 30 miles per gallon, that’s not 100% true all the time. Cars burn more fuel driving up hill, or when loaded up with people, or when driving super fast (air resistance) or just do to a literal thousand factors of physics involving the engine.
The point being an engine’s actual efficiency varies tremendously from moment to moment depending on the exact specific conditions of the car at that moment. Engine manufactures will do their best to “Target” the most common situation the engine will be driving in and “optimize” the engine to that specific condition. A civic engine might get 30 miles per gallon driving at 60 miles per hour on a flat highway with 2 people inside. The same civic might get 10 miles per gallon driving at 20 miles per hour in the same conditions.
Electric motors do not have this issue, they are much closer to being what you might think of as being “universally efficient”.
So the logic is, use the gas engine to charge a battery and optimize the engine’s efficiency for the exact “work” required to charge the battery. The ICE is now always operating right in it’s efficiency sweet-spot, getting theoretically best fuel mileage possible.
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