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Hybrid cars (混合动力车) are cars that run on petrol (汽油) and electricity. The have a small standard petrol engine (引擎) and a battery electric motor to provide electric power.

There are some differences between different models of hybrid cars, but the general principle is that the car runs on petrol, and the electric motor kicks in when additional power is required, for example, when going uphill. In some hybrid cars the petrol engine turns itself off when not needed, for example when the car has stopped at traffic lights, keeping only the electric engine running.

Traditional cars have large engines to cope with driving uphill. Most of the time, the high engine capacity is not needed, but the engine continues burning up fuel (燃料). Hybrid cars have much smaller petrol engines, improved by electric motors when needed, so they use less energy. Hybrid cars are also lighter and aerodynamically (空气动力学地) designed for greater fuel efficiency.

Another way that fuel consumption is cut by a system of “regenerative braking (刹车). The electric motor is used to slow down the car, rather than traditional brakes. The energy produced by slowing the car is changed into electrical power, which is automatically stored in the battery. In effect, the battery recharges when you brake. In traditional cars the energy produced when braking is wasted.

Car makers and engineers have been experiencing with electric and hybrid cars since the late 19th century. In 1898 Ferdinand Porsche built an experimental hybrid car. The first mass-produced hybrid car, the Toyota Prius, came out in Japan at the end of 1997. However, hybrid cars became available in the USA only in 1999, when the Honda Insight went on sale.

As they use less fuel, hybrid cars are cheaper to run. There are also many voices in some places to encourage people to buy them. In some countries, hybrid car owners pay a lower rate of tax, and don’t have to pay on certain roads. In some cities around the world, hybrid cars are allowed to park for free.