Conservation of energy and reduction in emissions emerge as significantly cautious for automobiles because of severe current emissions and energy situation. Many of experts have opinion that, majority of cars fitted with internal combustion engines are the major contributors of unhealthy emissions to the atmosphere which causes global warming and increase air quality index in urban areas. Internal combustion engines are accountable for the major pollution issues. As the energy calamity and atmospheric pollution are becoming remarkable in day to day life, hybrid electric vehicles (HEV’s) necessity for the world is in accelerated pace.