Valve train investigation for CNG engine application

Abstract

Compressed natural gas (CNG) beyond doubt has better emission byproduct as compared to petrol for compression ignition engines [1]. For greener environment retrofitted or converted vehicle was introduced into the automotive market. This work investigates whether the valve overlap period affects the vehicle engine performance. From the study, it was found that for a single overhead camshaft engine, the valve overlap period does affect the engine performance. The results show that retrofitting the present vehicle without modifying the valve overlap period is not suitable for CNG. It reduces the engine performance by about 9% for part open throttle conditions as compared to petrol. The present overlap duration should be increased for better performance.