To study the effects of intake port structure parameters (inlet area and throat area) of a gasoline direct injection engine on mixture formation, a steady-flow test and transient simulation with four kinds of intake ports (named Cases 1–4) were simulated using AVL FIRE; a four-valve, four-cylinder gasoline direct injection engine with Case 1 was also operated under wide-open-throat conditions with a speed of 5500 r/min as the test basis. According to the simulation results, the flow coefficient increased with an increase in throat and decrease in inlet areas; however, a reverse change of them can improve the tumble ratio. In addition, the tumble ratio in a cylinder can be increased by reducing the throat and inlet areas. However, the concentration is not notable at high-speed wide-open-throat conditions. A larger tumble ratio and stronger turbulent kinetic energy intensity of in-cylinder flow are beneficial to form a homogeneous mixture, which ensures a better distribution of air–fuel mixture at ignition time. Moreover, larger inlet area and smaller throat area ensure less NO emissions.
Study of particulate matter and gaseous emissions in gasoline direct injection engine using on-board exhaust gas fuel reforming
