Thermal Design And Strength Analysis For Engine Water Jacket

As a thermodynamic machine that can realize the conversion of thermal power,the engine has been widely used in our daily life.Influenced by energy crisis and emission regulations,more and more new technologies are being applied to the design of engines,so as to reduce weight,fuel consumption and emission,increase power.As a result,engine thermal load as well as mechanical load increasing dramatically,causing heavy impact on engine performance and safety.In order to decrease negative impact,we have to consider reducing the thermal load of the engine at the design stage,guarantee the engine work in a suitable temperature range,and ensure that the thermal-mechanical coupling strength as well as fatigue safety coefficient meet the standard.As a fast,accurate and low-cost research method,numerical simulation has been widely used in the process of engine water jacket design and strength verification.This article uses a three-cylinder turbocharged gasoline engine water jacket as a research object,utilizing CAE software(Hypermesh,Star-ccm+,ABAQUS,etc.)realized a range of simulations from engine water jacket CFD analysis to fluid-solid coupling temperature analysis,then optimize engine structure based on simulation results,eventually accomplished thermal-mechanical coupling strength analysis and fatigue safety factor check.The main contents of the work are as follows:(1)Using GT-suite software to establish a one-dimensional model of vehicle cooling system,type in parameters to calculate and obtain the boundary conditions of the three-dimensional flow field analysis of the water jacket.Conduct three-dimensional CFD analysis by using Star-ccm+,optimize water jacket based on results.(2)After optimization,conduct fluid-solid coupling temperature field analysis,improve structure design to reduce maximum temperature on engine.In order to verify the rationality of the optimization,conducting thermal-mechanical coupling strength analysis in ABAQUS,the result reveals that maximum strength meets the requirement;then some problem found by conducting fatigue analysis that safety factor in some area in the block exceed the specified value,optimization scheme has to be reconsidered.(3)By analysis a series of optimization scheme,it is determined eventually that add coolant flow path between cylinders.The new scheme has not only improved flow status in the water jacket and reduced engine maximum temperature,but also make sure the coupling strength requirements and fatigue safety factor meet the requirement.To summarize,by conducting a series of coupling simulation analysis,this article reveals problems in water jacket design,improve engine structure effectively,solve the over-temperature problem in engine,and ensure the engine strength is appropriate to the standard.It can be seen that numerical analysis can effectively save development costs,speed up the development process and shorten the project cycle.