Development And Design Of Marine High Power Diesel Engine And Research On Its Key Technologies

Diesel engine is the main active power equipment of ship,which has the characteristics of large torque,high reliability and excellent economy,and is increasingly favored by the world market.In recent years,due to the implementation of China’s marine power strategy,the military and civil need excellent high-power marine diesel engine,especially high-power medium and high-speed engine as the main engine of the ship.A ship needs to use 280 mm cylinder diameter diesel engine under the operation requirements of exhaust back pressure of 6.0k Pa and intake vacuum degree of 4.0k Pa.Generally,the design requirements of marine diesel engine are that both exhaust back pressure and intake vacuum degree are 2.5k Pa,which can not meet the operation requirements.Based on the simulation calculation of GT-POWER,this paper designs a marine high-power diesel engine which can meet the operation requirements of exhaust back pressure 6.0k Pa and intake vacuum 4.0k Pa,and carries out the bench test analysis.This study improves the accuracy and efficiency of the design,shortens the product development process,and is of great significance for the realization of the localization of marine diesel engine.In this paper,theoretical and experimental methods are used for the following research:First,the domestic and foreign status of marine high-power diesel engine,supercharger matching,intake and exhaust system are studied.According to the main performance design requirements of diesel engine,the overall design scheme of 280 high-power diesel engine is put forward.The principle of the four systems of the designed high-power diesel engine is analyzed,and according to the influencing factors of diesel engine performance and the evaluation of supercharging effect,the emphasis is put on the design Set up air inlet and exhaust system.Secondly,the mathematical model of the working process of the designed high-power diesel engine is established in detail.The thermodynamic system of diesel engine is divided into five systems: cylinder subsystem,intake system,exhaust system,air cooler system and turbocharging system,and the cylinder,intake and exhaust system and supercharger system are mainly studied.The mathematical model of combustion process in cylinder with quasi dimensional combustion is established,and the cylinder heat transfer model based on woschni formula is deduced.One dimensional unsteady finite is used According to the balance condition of compressor and turbine,the model of turbocharger is established,which provides the theoretical basis for the simulation of diesel engine working process.Then,based on GT-POWER software,the simulation calculation model of high-power diesel engine is established,and the pressure,charge coefficient and Mach number in the intake and exhaust pipe are analyzed,so as to optimize the structure size of the designed intake and exhaust pipe.Through matching JP350 supercharger and TPR61 supercharger,the data of the performance of diesel engine is analyzed and compared,and the joint operation curve of diesel engine and supercharger is given According to the optimization of injection advance angle and valve overlap angle,the comparative study and analysis are carried out to optimize the economy and power performance of the diesel engine.Finally,under the condition of exhaust back pressure 6.0k Pa and intake vacuum 4.0k Pa,the bench test of diesel engine is carried out,and the main performance data of diesel engine,such as boost pressure,maximum combustion pressure,fuel consumption rate,front turbine temperature,supercharger efficiency,surge margin,are obtained.The comparison between the test data and simulation calculation data verifies the correctness of the simulation model.The designed high-power diesel engine The oil engine meets the technical requirements.