Study On Airflow Characteristics Of Exhaust System For A Turbocharged Diesel Engine

The design of the exhaust system not only can have obvious effects on engine airflow character, but also have influence on exhaust gas energy utilization. So it hasdecisive influences on engine’s overall performance. Recent years, lots of researcheshave been done on exhaust system to improve energy utilization ration in exhaust gas toenhance performance of diesel engine. By means of designing exhaust system and matchmore suitable turbocharger the engine can reach optimum overall performance. In thispaper, detailed researches have been done on exhaust system parameters’ effects onexhaust process and engine performance by combining experiments and using onedimension simulation.The first step in the research is to build calculation model of the engine by softwareGT-Power, including cylinder zero dimension model, intake and exhaust system onedimension model, modules of turbocharger and intercooler, then the validity of the modelwas checked by comparison with experimental data. After the model was finished,conducted calculations for different exhaust pipe structure parameters, includingmanifold diameter, length and the ratio between exhaust pipe and manifold and theresearch mainly concentrated on pressure fluctuation in cylinder and exhaust pipe. Thiswork clarified the exhaust pipe parameters’ effects on exhaust process, especially thescavenging process.For further research, researches have been done on exhaust system parameters’effects on engine performance (brake power and volume efficiency). Besides, the effectspriority order of manifold diameter and length, exhaust pipe diameter and turbo inletdiameter on the engine performance had been researched and the influence relationshipsamong structure parameters of different exhaust system parts were ascertained.Finally, experimental research on exhaust pipe parameters was finished, mainlyfocused on influences of engine rotate speed and load on the dynamic response ofexhaust-manifold, scavenging efficiency and energy fluctuation at the turbine inlet.