Electronic controls watch over all components and make them work in harmony. In one hybrid, the Toyota Prius, a four-cylinder gasoline engine drives the wheels directly via the transmission, and also drives a generator to recharge the battery when it is running (Hybrid, 2003, 42). When the vehicle stops, the gasoline engine shuts down, preventing excessive pollution and fuel waste when in stopped traffic. When accelerating from stop to mid-range speeds the electric motor powers the car, fed by the battery. When the battery is becoming depleted, the gasoline engine kicks in to power the generator and recharge the battery. Running at steady speed under normal conditions, part of the engineÆs power goes to the generator to keep the battery charged, and part is used to turn the wheels. The distribution of these two energy streams is controlled continuously to maintain maximum efficiency. If sudden acceleration is needed, both the gasoline engine and the electric motor drive the wheels.
When the vehicle is braking, the kinetic energy is converted into electrical energy, which is stored in the battery (Hybrid, 2003, 42). This type of engine runs exclusively on gasoline, and the battery never needs chargin
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