Combustion Ionization for Detection of Misfire, Knock, and Sporadic Preignition in a Gasoline Direct Injection Engine

Abstract

Detection of combustion-related phenomena such as misfire, knock, and sporadic preignition is very important for the development of electronic controls needed for the gasoline direct injection engines to meet the production goals in power, fuel economy, and low emissions. This paper applies several types of combustion ionization sensors, and a pressure transducer that directly senses the in-cylinder combustion, and the knock sensor which is an accelerometer that detects the impact of combustion on engine structure vibration. Experimental investigations were conducted on a turbocharged four-cylinder gasoline direct injection engine under operating conditions that produce the above phenomena. One of the cylinders is instrumented with a piezo quartz pressure transducer, MSFI (multi-sensing fuel injector), a stand-alone ion current probe, and a spark plug applied to act as an ion current sensor. A comparison is made between the capabilities of the pressure transducer, ion current sensors, and the knock sensor in detecting the above phenomena. The signals from in-cylinder combustion sensors give more accurate information about combustion than the knock sensor. As far as the feasibility and cost of their application in production vehicles, the spark plug sensor and MSFI appear to be the most favorable, followed by the stand-alone mounted sensor which is an addition to the engine.

Pre-ignition-prevention control method in spark-ignition engines by detecting precursory cycles with an ion-current sensor

“…Tong et al 30 revealed that by detecting the abnormal increase in the ion-current signal before the spark-ignition signal, pre-ignition events can be detected as precisely as with the cylinder-pressure signal. Ayad et al 31 investigated three types of ion-current sensors: stand-alone ion probe, spark-plug type, and fuel-injector type, and succeeded in detecting the pre-ignition cycle by identifying the combustion start timing with all three types of ion-current sensors. On the basis of above prior research, it was proved that pre-ignition affects the timing at which the ion-current signal is generated.…”

Enhancement of knocking detection accuracy by an ion-current sensor integrated in the ignition system

“…Knocking phenomenon causes a high-frequency component in the ion-current signal, and that component can be used as an indicator of knocking intensity. Giglio et al (2009) showed that the oscillation of ion-current correlates with pressure oscillation induced by knocking, and Ayad et al (2019) compared the different types of ion-current sensors including a sparkplug type and a stand-alone type and concluded all of them could be applicable for knocking detection. Kinoshita et al (2000) concluded that the oscillation is caused by the change in ion density with a pressure wave, and the oscillation frequency depends on the polar character of the ion probe.…”