J. Du, B. Mohan, J. Sim, T. Fang, W.L. Roberts
Experimental Thermal and Fluid Science 112, 109993, (2020)
Ignition delay, Diffusion combustion mode, Partially-premixed combustion mode, Low carbon fuel
Gasoline compression ignition (GCI) engines have proven to be a highly efficient engine technology with reduced emissions. The high efficiency and reduced emissions of GCI engines heavily rely on the stratification of the fuel being injected directly into the cylinder through multi-hole injectors. Therefore, it is critical to understand the fuel stratification and auto-ignition behaviors of the fuels used in GCI engines. Thus, in this work, the auto-ignition characteristics of high-reactivity and low carbon gasoline fuel (RON 77) were studied in an optically accessible constant volume chamber. A customized high-pressure gasoline multi-hole injector was used. Reactive tests were performed at two different ambient pressures (20 and 30 bar), three different ambient temperatures (800, 900, and 1000 K), three different oxygen concentrations (10, 15 and 21%) and three different injection pressures (100, 300 and 450 bar). The auto-ignition of fuel was achieved with varying ignition delay based on the experimental conditions tested. It was found that the operating conditions profoundly influences the diffusion and partially-premixed combustion mode. For high ambient pressures, temperatures, oxygen concentrations, injection pressure, and combinations, diffusion combustion mode was observed, and partially premixed combustion mode was observed at lower ambient pressures, temperatures, oxygen concentrations, injection pressures, and their combinations.