Study On Design And Characteristics Of Gasoline Engine Inlet Port

Engine combustion process which has an significant impact on engine’s power,fuel economy and emission characteristics can be effectively optimized by well designed inlet port.The research means which is widely used in modern inlet port designing and researching process combines CAD,CFD and steady flow test together.The influence of geometrical structure on flow capacity and tumble characteristics of a 1.5-liter displacement turbocharged gasoline engine inlet port was investigated.Inlet design and research status at home and abroad was fully investigated.The mathematical model involved in the numerical simulation of steady flow in inlet port was summarized.A steady flow simulation model of inlet port was constructed.An automated computing platform which can automatically call Hypermesh,Meshworks,STAR-CCM+ to complete the simulation calculation work was built with modeFRONTIER.The steady-state flow simulation of inlet port designs with various geometric structure was carried out.After comparing and analysing calculation results,the influence of geometrical structure on inlet port flow capacity and tumble characteristics was summarized.Steady flow test was carried out on the representative inlet port design.The inlet port core box was fabricated by rapid prototyping.The laws got from the calculation were verified by tests.The following laws were found.Firstly,the smaller the angle between the inlet port centerline and the cylinder axis is,the stronger the circulation capacity of the inlet port is,and the lower the strength of the in-cylinder tumble is.Secondly,increasing the inlet area of the inlet port will increase the flow capacity of the inlet port and the strength of the in-cylinder tumble.Thirdly,under the premise of the same inlet flow area,indenting the inlet shunt parts in the direction of flow can increase the tumble strength in the cylinder to a certain extent.Finally,with the laser cladding technology processing valve seat,the straight segment at the valve seat can be shorted,the ability of the inlet port to form a tumble is enhanced,but the flow capacity of the inlet port is weakened.The results of the study have a positive effect on the understanding of the inlet port and in-cylinder gas flow providing a strong basis for the optimal design of engines.