Board Boosted Gasoline Engine Preignition Diagnostic

Abstract:

The experiment was conducted on a MPI boosted gasoline engine to analyze the influence of intake temperature, engine load, ignition timing and lambda on preignition frequency on the basis of the incylinder ioncurrent detection. The results show that small variation of intake pressure will not increase preignition events significantly. Higher engine load and advancing ignition timing will lead to higher preignition frequency. Incylinder enrichment will decrease its frequency but a higher fuel consumption instead. At the start of preignition event, obvious ion current signal can be detected. Compared with the cylinder pressure threshold method, ion current detection can find out all the preignition events, including the cycles with lower combustion pressure. Especially, the characteristic ion current signal of preignition can be detected 25°CA BTDC. This provides a potential control to suppress preignition events for modern engines.