Hybrid car is an automobile that uses more than one source of energy for propulsion. A common type of hybrid car has both an internal-combustion engine that burns gasoline and an electric motor powered by a battery. The drive shaft, which delivers power to the wheels, may use power from the engine, the motor, or both. For example, both systems may supply power during acceleration, while the electric motor may supply all of the power for cruising. When the engine is not needed for propulsion, it charges the battery. During braking, the motor functions as a generator, using the energy of the vehicle’s momentum to charge the battery. This process is called regenerative braking.
Another type of hybrid vehicle includes a hydraulic motor-generator and an accumulator for storing fluid under pressure. The fluid is discharged into the system to operate the generator. Hybrid vehicles with fuel cell systems convert chemical energy from a fuel, such as hydrogen or gasoline, directly into electrical energy.
Hybrid cars produce better fuel economy than comparably sized vehicles powered only by internal-combustion engines. Hybrids also provide acceleration, speed, and handling comparable to those of other automobiles. However, their systems are more complex and the vehicles are more costly to produce. The first mass-produced hybrid car, the Toyota Prius, was first sold in Japan in 1997.
See also Electric car; Fuel cell.
