The Selection And Design Of Two Stage Turbocharging System For Medium Diesel Engines

Poles to a sharp rise in the outside all characteristics of supercharging diesel engine,a sharp rise in the low speed torque,maximum torque and improve the power density,is to realize the euro V,VI emission requirements of one of the important technology.This paper will study it and find out the method and key points of the two-stage supercharging performance matching and design,so that the two-stage supercharging technology can be used in batch in China as soon as possible.Yuchai 6L supercharged diesel engine,which is the first successful supporting diesel engine in China.We have carried out comprehensive research and development from the aspects of performance selection,layout design,simulation analysis and test verification.First,Using BOOST performance simulation software,the performance plan of the most suitable bipolar supercharger was selected,and the performance of the diesel engine was predicted.The research shows that the pressure ratio and the flow range can significantly increase the low speed torque and maximum torque and maximum power.The pressure ratio of the pressure ratio between the two poles is better than that of the pressure ratio:the pressure ratio is about 3:2.If the bypass valve of bypass valve is limited,the gas loss of engine pump will increase under high working conditions,and the oil consumption will worsen.BOOST performance simulation results are close to the test results and the error is within 10%.BOOST performance simulation can greatly shorten the performance development cycle and save development cost.Second,According to the choice of performance simulation calculation of the scheme,from the concept of layout,the layout design and detailed design poles pressurization layout design was carried out on the three stages,and select suitable according to the requirements of the whole space and the truck poles pressurization layout scheme.Using the CAE method to analyze the strength analysis,modal analysis and the uniformity of EGR rate of the supercharging system,based on the calculation results,the risk points were predicted and the optimization plan was put forward.The support of the low pressure stage supercharger is essential,and the arrangement of the connecting line should be as smooth as possible,avoiding mutation and reducing flow loss.Finally,Through the performance test,vibration test and reliability test,the accuracy of the simulation analysis method has been verified,which has achieved the expected performance and reliability index of the whole machine,and completed the matching work.The CAE simulation analysis method is proved to be effective,and the CAE simulation analysis can greatly reduce the test plan,select the optimal scheme,shorten the development cycle,and save the development cost.