Study of Fuel Octane Sensitivity Effects on Gasoline Partially Premixed Combustion Using Optical Diagnostics
To be published on September 9, 2019 by SAE International in United States
Partially premixed combustion (PPC) is a low-temperature combustion (LTC) concept that could deliver higher engine efficiency, as well as lower NOx and soot emissions. Gasoline-like fuels are beneficial for air/fuel mixing process under PPC mode because they have superior auto-ignition resistance to prolong ignition delay time. In current experiments, the high octane number gasoline fuel E10 (US market used gasoline, RON=91) and low octane number GCI blend fuel (RON=77) were tested respectively in a full-transparent AVL single cylinder optical compression ignition (CI) engine. Aiming at investigating the fuel sensitivity on engine performances under different combustion modes as well as soot particle emissions, the engine operating parameters and emission data were analyzed from CI to HCCI (homogeneous charge compression ignition) via PPC (partially premixed combustion) by changing fuel injection timing. In addition, in order to get a deep insight of in-cylinder auto-ignition and combustion evolution process, planar laser-induced fluorescence (PLIF) imaging and high-speed natural flame luminosity (NFL) imaging techniques are used for visualizing fuel distribution, auto-ignition kernel development and combustion processes.