Techniques for Reducing the Environmental Load in Vehicle Transportation. On the Hybrid Electric Vehicles.

To reduce the global warming effect, it is important to reduce the energy spent in transportation sector, especially spent by the vehicles. Because, over 20% energy is spent in transportation sector, and more than 80% energy in transportation sector are spent by the vehicles.Effective way to improve the energy efficiency of the vehicle is to introduce the electric motors instead of the internal combustion engines. Motor driven vehicles (or motor assisted vehicles) such as electric vehicles, hybrid electric vehicles and fuel cell vehicles (or fuel cell hybrid vehicles) are expected to become widespread near future.This paper describes current status of EV technologies and technical trends in hybrid vehicles/fuel cell vehicles.Fuel cell vehicle has a lot of subjects to be solved before popularizing, for example, costs and life of cells, efficiency in actual driving conditions, selection of fuel source, infrastructure for fuel supply and so on. On the contrary, hybrid electric vehicle will be most promising low emission and high efficient vehicles to be put into practical use near future. Various types and levels of hybridization may exist and will be accepted corresponding to the variety in utilization.Features of the HEVs on the market and prototype HEVs developed by the manufactures or developed in the governmental project are also listed. These features lead to the fact that the fuel efficiency can be improved up to twice of one in conventional internal combustion engine vehicles' by hybridization.