Impacts of Ignition and Jet Timing on Natural Gas Engine Start Process

Based on modified natural gas direct injection engine, we studied the impacts of ignition timing and jet timing on natural gas engine start process in this paper. The results shows that: when the first jet ignition occurs in the first compression stroke, the engine reaches idle speed 400rpm fastest; as the jet timing is delayed, emissions during engine start is gradually reduced, but when the jet late, HC surge occurs, the emissions deteriorates; with the ignition advance angle increasing, the engine speed growth accelerates, the peak moves forward; with the ignition advance angle increasing, HC emissions peak increases, the peak moves forward.