Hybrids are driven by two power sources, or propulsion systems. For instance, some locomotives have both diesel and electric motors, while some submarines have nuclear and electric power sources.
A typical hybrid car or truck is powered by both a gasoline-powered engine and at least one electric motor. These two power sources take turns or work together to move the vehicle. As the internal combustion engine runs, it charges the electric motors’ batteries. The batteries then help to power the vehicle, taking some of the energy requirements off the engine. This combination allows the internal combustion engine to run more efficiently, using less fuel and producing fewer emissions.
Gasoline and diesel engines burn fuel, which produces emissions. But they produce lots of horsepower very effectively.
Vehicles powered by electricity alone are expensive, have very limited range and must rely on heavy batteries for power storage. But they produce lots of torque to launch a vehicle without the emissions.
Combining these two existing technologies helps reduce pollution and dependence on fossil fuels until more long-term solutions, such as hydrogen-powered fuel cells, are developed.