Effect of Hydrous Ethanol Combined with EGR on Performance of GDI Engine 2020-01-0348
In recent years, PM emission from GDI engines has been gradually paid attention to, while the hydrous ethanol has a high oxygen content and a fast burning rate, which can effectively improve the combustion environment. In addition, EGR can effectively reduce engine NOx emissions, and combining EGR technology with GDI engines is becoming a new research direction. In this paper, the effects of hydrous ethanol gasoline on the combustion and emission characteristics of direct injection engines are analyzed through direct injection engine bench test. The results show that the increase of the proportion of hydrous ethanol accelerates the combustion rate, shortens the combustion duration, and peaks the cylinder pressure and heat release rate. At the same time, the combustion efficiency is improved. The hydrous ethanol gasoline can effectively improve the gaseous and PM emissions of the direct injection engine. The concentration of CO, HC and the amount of PM is significantly reduced, and the particle size of the particles is transferred from the accumulation state to the nuclear state. Furthermore, a one-dimensional simulation model was established by GT-power to study the dual effects of EGR technology combined with hydrous ethanol gasoline. The results show that the introduction of EGR can improve the fuel economy under partial load. The emission results show that the combination of hydrous ethanol gasoline and EGR can improve combustion enviroment, which makes CO and HC emissions lower than pure gasoline. EGR can also relieve the high NOx emission of hydrous ethanol gasoline. The combination of the two can effectively improve the combustion and emission performance of GDI engines.