Study Of Simulation And Experiment On Different Turbocharging System Of 20V956 Diesel Engine

The 956 diesel which owns two turbochargers is a diesel propulsion engine used in shipping area.The diesel supercharger performance is poor,the effective specific fuel consumption is high and the economic performance is poor under the condition of generation operation.Hence the supercharging system of 956 diesel is changed in order to improve the engine performance.In this paper,the experiments are designed to measure the burning and performance parameters of the 956 diesel propulsion engine and diesel generating engine,and the analysis of 956 diesel heat release rate patterns is carried out,based on the test of cylinder pressure,the critical combustion characteristic parameters are obtained,the variation of the combustion parameters is verified,the empirical model of the combustion characteristic parameters is established based on the Wiebel combustion model.With the use of diesel simulation software GT-Power,two types(two turbochargers and four turbochargers respectively)956 diesel simulation models are established respectively.By checking and comparing with the experimental results,and the maxium error satisfy the requirement of less than 4.73%,the precision requirement of simulation calculation is reached.In regard to the two and four supercharging system of 956 diesel,the parameters of air system,combustion and performance are calculated under the condition of generation operation.The acquired results are compared and showed that the performance and the fuel economy are better when the RPM is 1500r/min,the system is in parallel and supercharged.The effective specific fuel consumption is reduced by 4.96g/(kW·h),and such result fits experimental results.This paper discusses the influence of injection timing,valve timing,the size of turbocharger on the working process of 956 diesel generating engine,based on the supercharging in parallel system,and obtains the optimized parameters by analyzing the law.Finally the effective specific fuel consumption is reduced by 1.05g/(kW·h)when the RPM is 1500r/min and the load is 100%.