汽油机无节气门SVSC系统的仿真分析

Simulation Analysis of SVSC Intake System of Gasoline Engine Without Traditional Throttle Valve

设计一种无传统节气门的新型串联气门速度控制(series valve speed control,SVSC)系统替代点燃式发动机传统节气门式进气系统,在一定范围内实现气门正时连续变化,降低发动机中小负荷时进气过程的泵气损失,提高燃油经济性。以试验数据为参数,基于数值模拟软件GT-power搭建某单缸汽油机模型,并基于Ansys-fluid软件进行数值分析。通过对比SVSC和节气门2个进气系统整个工作循环的示功图和各状态参数、内部流体的压力、速度、温度云图等,分析2种系统在相同工况下的泵气损失以及内部的流体状态。结果表明:发动机在相同状态的中小负荷下,与传统节气门式进气相比,SVSC系统内部流体的节流损失小,进气前后的压差和进气过程中的泵气损失小,燃油消耗率低,发动机的燃油经济性好。

A new type of ignited engine intake system, called the series valve speed control system (SVSC), is designed to replace the traditional throttle type intake system.The system cancels the traditional throttle valve, and can realize the continuous change of the valve timing within a certain range, which can reduce the pumping loss of the engine during the intake process under medium and small load, thereby achieving the purpose of improving fuel economy. A single-cylinder gasoline engine as an example and the experimental data as a parameter,the numerical analysis is carried out based on the numerical simulation software GT-power and Ansys-fluid software.The PV diagrams of the whole working cycle of the two intake systems are obtained. The pumping loss and internal fluid status are analyzed under the same conditions by contrasting the mentioned diagrams, the state parameters, the internal fluid pressure, the velocity and the temperature maps. The results show that contrasted with the traditional throttle-type intake, the throttle loss of the internal fluid of the SVSC system is small under medium and small load of the same state, and the pressure difference before and after the intake and the pumping loss are small, the fuel consumption rate is low, and the fuel economy of the engine is good.