Power in Hybrid cars is drawn from a conventional gasoline engine and an electric motor. One motor provides cruising power while the other motor kicks in for quick acceleration. The electric motor recharges during braking and enables some of the hybrids to coax a gallon of gas for more than 40 miles.
The two power sources found in hybrid cars can be combined in different ways. One way, known as a parallel hybrid, has a fuel tank, which supplies gasoline to the engine. But it also has a set of batteries that supplies power to an electric motor. Both the engine and the electric motor can turn the transmission at the same time, and the transmission then turns the wheels.
In a typical parallel hybrid the fuel tank and gas engine connect to the transmission. The batteries and electric motor also connect to the transmission independently. As a result, in a parallel hybrid, both the electric motor and the gas engine can provide propulsion power.
In a series hybrid the gasoline engine turns a generator, and the generator can either charge the batteries or power an electric motor that drives the transmission, thereby the gasoline engine never directly powers the vehicle.
The hybrid car has a gasoline engine much like the one you will find on most cars. However, the engine on a hybrid is smaller and uses advanced technologies to reduce emissions and increase efficiency.
The fuel tank in a hybrid is the energy storage device for the gasoline engine. Gasoline has a much higher energy density than batteries do.
The electric motor on a hybrid car is very sophisticated. Advanced electronics allow it to act as a motor as well as a generator. For example, when it needs to, it can draw energy from the batteries to accelerate the car. But acting as a generator, it can slow the car down and return energy to the batteries.
The generator is similar to an electric motor, but it acts only to produce electrical power. It is used mostly on series hybrids.
The batteries in a hybrid car are the energy storage device for the electric motor. Unlike the gasoline in the fuel tank, which can only power the gasoline engine, the electric motor on a hybrid car can put energy into the batteries as well as draw energy from them.
The transmission on a hybrid car performs the same basic function as the transmission on a conventional car. Some hybrids, like the Honda Insight, have conventional transmissions. Others, like the Toyota Prius, have radically different ones.
The Big Three automakers are once again behind the Japanese on bringing these fuel efficient cars to the American market. Toyota's Prius and Honda's Civic Hybrid and Insight are the only hybrids in the mass American market. Ford will begin distributing hybrid versions of its Escape SUV in August 2004. General Motors plans to unveil several hybrid pickups in fall 2004. GM boasts that it is delivering the world's first full-size hybrid pickup, a special Chevrolet Silverado.