A gasoline – electric hybrid vehicle or hybrid electric vehicle (HEV) is a vehicle that can be powered by either gasoline or electric and is designed as a cross between the two.
Why does a car need both forms of power?
As a modern consumer, it is important that your vehicle meets some minimum requirements in terms of range, speed, and ability to refuel. We need our cars to have a range of at least 300 miles, be easy to refuel, and have a speed that keeps up with other cars that are on the road.
A gasoline vehicle can meet all of these requirements. However, a gasoline car is inefficient which means it has poor gas mileage and produces pollution. An electric car produces almost no pollution, but currently does not have the range or speed of a gasoline car. In addition, recharging is relatively easy, but it is not quick and the infrastructure is not in place.
A hybrid vehicle takes the advantages of an electric car and a gasoline car to make an automobile that is more fuel efficient, but can still meet the demands, in terms of range and speed, of customers. Hybrid vehicles have a gasoline engine and a gasoline fuel tank. In addition, they have an electric motor, a generator, batteries, and a transmission. The batteries are usually nickel metal hydride (NiMH) batteries, which are more reliable then lead acid batteries.
There are two basic configurations for HEVs. The first is called a parallel hybrid. In this setup, both the gasoline engine and the electric motor can turn the transmission which then turns the wheels. The second configuration is called a series hybrid. In this arrangement, the gasoline engine is not connected directly to the transmission. Instead, it turns a generator that then either charges the batteries or powers the electric motor that then turns the transmission.
Even hybrids of the same configuration vary in their design. To distinguish between the different designs, it is customary to refer to hybrids as mild, full, or plug-in.
Mild: The electric motor and battery assembly assist the traditional gasoline engine.
Full: Two full propulsion systems are available on the vehicle.
Plug-in: The gasoline engine acts only as a back-up to the main electric motor and battery assembly.
A mild hybrid always needs the gasoline engine to move the vehicle forward. On the other hand, a full hybrid can use the electric motor only to move the vehicle forward. The gasoline engine does not always need to be running. The controllers on the vehicle will know when the vehicle is under a light load condition such as cruising or light acceleration and the gasoline engine will be turned off. Most hybrids also shut the engine off when the vehicle comes to a stop to avoid wasting energy while the vehicle is idling.
In order to get the best fuel economy gains, hybrids use many technologies in combination with the dual engine arrangement. For example, because the electric motor is able to drive or assist the gasoline engine, the engine can be smaller and more fuel efficient. In addition, regenerative braking is used to capture the energy that is normally lost when the vehicle is slowing down. The energy is captured through the electric motor, running in reverse, which then charges the batteries. When there are periods when little braking occurs, the gasoline engine can also be used to operate the electric motor as a generator to charge the batteries.
Hybrid technology is in the development stage. Automotive manufacturers are all introducing their own versions of the technology. In addition, they are all selecting different types of vehicles to target for hybrid introduction. The competition created by this new technology should allow customers to benefit from increase fuel economy standards throughout the years to come.