This paper establishes an operating process of calculation model which is adjusted by the experimental results of speed characteristic. It simulates the performance of 4100 direct injection diesel engine by using simulation software AVL BOOST and carring out overall power experiment of the model of the engine. This paper also specifically analyzes the effects of compression ratio and injection timing on performance of the 4100 direct injection diesel engine

and then confirmed appropriate compression ratio and injection timing. Compression ratio and injection timing of original engine was adjusted by optimization result

and then engine experiment was carried out to compare the performance of engine ameliorated with original one. The result shows that e the dynamic performance is improved while the fuel consumption rate rises a little and the emission of diesel engine is reduced a lot to achieve the purpose of exploiting diesel engine of the low emission

which can save the manpower 、materials cost and financial resources in the study of diesel engine.