Study On Diesel Engine Performance Based On Hydraulic Valve System

Energy shortage and more rigorous emission regulation maked the automobileenterprises and research facilities begin to use more new technologies to produceenvironmental, efficient and energy saving. Among them, variable valve technologywhich can make the volume efficiency reach the maximum at different speed byadjusting valve timing and lift was widely used.Selected the CA498diesel engine as the prototype, and build theone-dimensional simulation model based on the prototype parameters and bench testby GT-Power. Contrasting the simulation data and experimental data, the resultshowed that the error between parameters of the simulation and experimentaldata was less than5%,such as torque and specific fuel consumption, so this model canreflect the real working condition of prototype.In order to research how the hydraulic valve system affected diesel engineperformance, designing the hydraulic valve system based on the CA498diesel engineand used it to replace the original cam driving valve system which had a constantvalve timing. And used SimulationX to build the model of hydraulic driving variablevalve system, then used this model to simulate opening and closing curve of intakeand exhaust.This lift curve was used in the hydraulic driving valve diesel enginemodel to simulate the engine working process when it had the same timing andmaximum lift with prototype, analyzed how the hydraulic driving model affecteddiesel engine. Finally, optimizing the valve timing and analyzed the simulation result.Simulation result showed that if the valve timing and maximum lift of hydraulicvalve diesel engine was same with the prototype,the cylinder pressure will dropmarkedly when the exhaust valve open at the lower speed operation condition, andthis will affect engine power, it was because that opening speed of hydraulic drivingvalve diesel engine was higher than prototype. The performance of hydraulic valvediesel engine was improved markedly when its valve timing was optimized, and theamplification of power was5.3%-9.8%,the falling range of specific fuelconsumption was5%-8.9%.