Hybrid Electric Vehicles
29 June 2011 | Source: Independent Resources
A hybrid electrical vehicle (HEV) is a vehicle equipped with either an internal combustion engine (ICE) and an electrical motor powered by electrical batteries. In 1997, Toyota sold in Japan the first modern hybrid electric car, the Toyota Prius. Today’s HEVs are an emerging technology in the automotive market, with manufacturers designing and producing hybrid systems for passenger cars, light-duty vehicles, heavy duty vehicles, and even locomotives. The improved efficiency of HEVs over conventional (i.e. nonhybrid) vehicle is achieved by operating a smaller (more efficient) ICE within a narrower, more efficient operational speed/power band and using an electric engine and electrical storage (i.e. the battery) to balance the performance energy requirements. In general, in the current-generation HEVs, the combustion engine provides the main power during long-distance drive while the electrical motor can either complement the ICE or power the vehicle in electriconly mode (as long as energy is available from the battery) during the urban service, where the ICE is less efficient. The battery charge is provided by regenerative braking and excess energy from the ICE (stored when the vehicle has lower power requirements). There are however different grades of hybridization and many configurations of hybrid vehicles, including micro, mild, full hybrids, with different role for the electric motor. Currently, only hybrids combining a petrol or diesel combustion engine with an electric motor are commercially available. Improving battery capacity and technology may enable longer electric drive range and reduce the need for the ICE contribution. Newgeneration HEVs include batteries rechargeable from the grid (known as plug-in hybrid electrical vehicles, PHEVs, see also ETSAP TB05).