Hybrid electric vehicles are automobiles which make use of a combination of conventional propulsion systems and rechargeable energy storage systems (RESS). The purpose for combining these two different power sources is to achieve improved fuel economy in hybrid electric vehicles compared to the conventional cars and trucks. Moreover hybrid electric vehicles incorporate propulsion systems in addition to the electric motors, in order not to be hampered by charging units the way it happens with battery electric vehicles (BEVs).

Modern times have seen the mass production of hybrid electric vehicles coming from a number of well known car manufacturers. The reasons why many car producers jump on the green bandwagon are varied. Whether there is a genuine interest in saving energy and not using the planet?s energetic sources, or a smart and “caring” way to attract buyers and thus sell more cars, one cannot be certain. There are three main ways that allow current hybrid electric vehicles to reduce gas consume. First, they lower the amount of wasted energy during idle or low input (turning off the ICE); secondly, they collect waste energy (regenerative braking), and thirdly, they reduce the size and power of the ICE and inefficiencies generated by under-utilization.

The modern mass-produced hybrid electric vehicles are able to prolong the charges on their batteries simply through collecting the kinetic energy via the regenerative braking system. Some hybrid electric vehicles use the internal combustion engine (ICE) to create electricity by spinning an electrical generator (quite often this is a motor-generator) to directly supply the electric motor that drives the vehicle or to recharge the battery. Many of the existing hybrid electric vehicles? capability is to reduce idle emissions by shutting down the internal combustion engine at idle status and restarting it when necessary (this is a start-stop system). The engines of the hybrid electric vehicles are smaller than those of non-hybrid petroleum fuel vehicles. These engines may function at various speeds, thus bringing more efficiency.

The making of the hybrid electric vehicles started in the late 1990s and the first ones came from Honda (Honda Insight) and Toyota (Toyota Prius). Even since beginnings of hybrid electric vehicles they have become widely available to the buyers. The future of hybrid electric vehicles is definitely bright, and this is the forecast by some automobile makers who consider hybrid electric vehicles a core segment of the automotive market of the future.