Experimental Investigation of the Compression Ignition Process of High Reactivity Gasoline Fuels and E10 Certification Gasoline using a High-Pressure Direct Injection Gasoline Injector 2020-01-0323
Gasoline compression ignition (GCI) technology shows potential to obtain high thermal efficiencies while maintaining relatively low soot and NOx emissions in light-duty engine applications. Recent experimental studies and numerical simulations have indicated that high reactivity gasoline-like fuels can further enable the benefits of GCI combustion. However, there is limited combustion data in the literature studying the gasoline compression ignition process at relevant in-cylinder conditions which are required for further optimizing combustion system designs. This study investigates the temporal and spatial evolution of the compression ignition process of various high reactivity gasolines with research octane numbers (RON) of 71, 74 and 82, as well as conventional RON 97 E10 gasoline fuel. Combustion visualizations were conducted in an optically accessible constant volume combustion chamber. A ten-hole prototype gasoline injector specifically designed for GCI applications to be capable of injection pressure of up to 450 bar was used. OH* chemiluminescence and natural luminosity images were recorded simultaneously to characterize the ignition process through two high speed cameras. The experiments were conducted under a wide range of ambient charge gas conditions including temperatures from 900 to 1200 K and charge pressures from 50 to 100 bar with oxygen levels from 10-21% to represent 0-50% exhaust gas recirculation (EGR) levels. The fuel was injected at 300 bar and 450 bar injection pressure. Results show that the ignition delay decreases and flame lift-off length moves upstream from the injector tip with increasing ambient temperature, increasing charge pressure, decreasing EGR level and decreasing RON number.
Jiongxun Zhang, Meng Tang, William Atkinson, Henry Schmidt, Seong-Young Lee, Jeffrey Naber, Tom Tzanetakis, Jaeheon Sim
Michigan Technological University, Aramco Services Co., Saudi Aramco