One current popular environmentally-friendly transportation alternative is the hybrid car. A hybrid car is a passenger vehicle that uses two separate engine types. These are commonly gasoline and electric. There are diesel/electric hybrids but they are not common in the U.S. Gasoline/electric hybrids are made in two types: parallel and series.
In a parallel hybrid car, both the gasoline engine and the electric motor operate together to propel the vehicle. In contrast, the series hybrid features either a gasoline engine that directly powers the electric motor, and, in turn, the vehicle or the gasoline engine charges the batteries that power the electric motor.
Regenerative braking is a feature common to both types of hybrid cars. This process stores the energy used in braking in the batteries which power the electric motor. In a traditional braking system, you step on the brake and remove energy from the car. The brakes remove this energy and remove it in the form of heat. In the hybrid, this energy is stored in the battery for later use.
Both types of hybrids have small gasoline engines, which produce less pollution than standard cars. However, the small engine also results in the hybrid having only about 50% of the power of a regular car. A hybrid may only generate sixty to ninety horsepower.
Some hybrid cars will periodically shut off the gasoline engine—such as when the car is idling at a stoplight.
To overcome the lower power level, hybrid cars are designed with lightweight materials such as aluminum, magnesium or carbon fiber. Hybrids are also designed to maximize aerodynamics and slice through the air with a minimum of wind resistance. This may be accomplished by sleek front end design and even by replacing protruding mirrors with cameras.
Another way to reduce resistance is by making modifications to tires. Regular tires are designed to provide a smooth quiet ride and good traction in different weather conditions. But they also create a lot of drag. The tires on hybrid cars are stiffer and inflated to higer pressure, eliminating about half the drag of regular tires.
Hybrid car technology is under constant improvement to improve efficiency and provide an environmentally friendly transportation alternative.