Air hybrid 엔진 기술 개발을 위한 기초 타당성 연구

A preliminary study of new concept air-hybrid engine, which stores compressed air in the tank during braking and re-use it to propel vehicle during crusing and acceleration, was carried out in this study. A single cylinder engine with displacement volume of 500㏄ and 4 valve DOHC system was modified to realize the concept of air-hybrid engine. Independent variable valve lift system, which can varies valve lift from 0 to 5 ㎜, was adopted in one of exhaust valve to store the compressed air in the air tank during compression stroke. For air motoring mode, air injector module was installed in place of spark plug and compressed air was supplied during the expansion period. The test engine was operated at the engine speed of 800 and 1,500 rpm with various throttle positions. For air compression mode, the tank with volume of 30 liter could be charged up to more than 13 bar at the engine speed of 800 rpm and full throttle condition by optimizing valve lift and timing. For air motoring mode, gas injector for heavy duty compressed natural gas engine was installed in place of spark plug. Compressed air charged in the air tank was injected with this gas injector during the expansion period of piston.