Study On Simulation Of SVSC System In Four-Cylinder Gasoline

As domestic automobile ownership is constantly escalating and national environmentalregulations and fuel consumption regulations are increasingly rigid,the practitioners of automobile industry have to pay more attention to the promotion of engine performance.Moreover,on the premise of ensuring the performance,the emission and economical efficiency of the engine should also be taken into account.At present,variable valve technology,variable compression ratio technology,technology of direct injection in cylinder,turbocharged technology and homogeneous charge compression ignition technology have been widely used in gasoline engines,which still have their respective advantages and disadvantages.Besides,if any of these technologies is applied to 4G20D4 gasoline which is target type in this project,there will be some problems such as large improvement cost,huge change in the work,etc.That can not reach the purpose of improving its performance,especially fuel economy,in limited cost control.As a new-type non-throttle valve system of gasoline engine,SVSC had a great effect on reducing pumping loss,which was a very suitable alternative for the improvement of the4G20D4 engine.Because engine pumping loss was the primary reason causing low thermal-kinetic energy conversion efficiency and low fuel economy in the traditional spark ignition(SI)engine performance,the use of SVSC system without air damper will reduce the pumping loss of the gasoline engine and increase the overall efficiency.Firstly the principle and design ideas of SVSC system were introduce in this paper,including how to realize the valve timing continuously adjustable and some advantages over traditional throttle valve.Then the simulation model of the 4G20D4 prototype was established with the GT-POWER software and the 4G20D4,the original machine,was carried out the bench testing.The simulation data of 4G20D4 gasoline engine,including the total power,the total torque and the fuel consumption rate were compared with the test data of the original machine,and it was concluded that the simulation model was accurate.Secondly,based on the accurate simulation model of the original machine,the air intake system was improved.When the traditional throttle valve model was full open,SVSC system model was added and the simulation calculation was done.Compared with the previous data,it was concluded: the fuel economy of 4G20D4 gasoline engine equipped with SVSC system under medium and low load was increased by about 10%.,and performance under full load working conditionwas basically the same.Therefore,it was proved that it was significative to research4G20D4 gasoline engine equipped with SVSC system.In this paper,the preliminary design for the physical carrying of the SVSC system was undertaken with three-dimensional software,which laid solid foundation for the actual application of the SVSC system in the four cylinder machine in the future.