Experimental study on combustion characteristics of a fischer-tropsch diesel/methanol reactivity controlled compression ignition mode engine

F-T diesel is an alternative fuel with a high cetane number (CN) for internal combustion engines. Methanol has a low CN and contains oxygen. F-T diesel and methanol are potential fuels for the reactivity controlled compression ignition (RCCI) engines. In a single-cylinder 186FA compression-ignition engine with a combination of methanol inlet pipe injection and F-T diesel in-cylinder injection, the combustion characteristics of the F-T diesel/methanol RCCI mode engine are investigated. The results show that as methanol premixed ratio (MPR) increases, the ignition delay (ID) is prolonged at low load conditions, the maximum in-cylinder pressure (P-max) and indicated thermal efficiency (ITE) a decreased. When the MPR increases from 0% to 60%, the ID is extended by 1.7 degrees CA, the P-max decreases by 8.1%, and the ITE decreases by 1.1%. At high load conditions, MPR rises from 0% to 60%, combustion duration (CD) is shortened by 2.4 degrees CA, P-max is increased by 8.3%, and the ITE is increased by 1.7%. The fuel injection advance angle (IAA) of F-T diesel significantly influences the combustion process of the RCCI engine. As the IAA increases, the ID is shortened at high loads, and the P-max and the ITE are increased. When the MPR is 60% and the IAA is 14 degrees CA, the ITE of the engine is increased by 2.04%, and the equivalent indicated fuel consumption rate(b(e)) is reduced by 5.68% compared with the engine fueled with F-T diesel under high loads.