YC6J-30 series diesel engine is implemented in the III and IV national standards, to replace the original YC6J-20 emission of the engine in China ii. The development of modern diesel engine using a number of scientific and technological achievements, is to learn from the world famous German FEV automobile engine technology advanced design ideas and means, Yuchai independent development and design of a diesel engine, more suitable for the use of the China. The development of mechanical reference mechanical development program of German FEV company, the reliability is well guaranteed; the service life under normal operating conditions is greater than 800000 km.