Detection of Combustion Resonance Using an Ion Current Sensor in Diesel Engines

Abstract

This paper discusses the use of an ion current sensor to detect combustion resonance in a heavy duty direct injection diesel engine. A modified glow plug is used to measure the ion current in addition to its main function in warming up the combustion chamber. A comparison is made between the combustion resonance determined from the signals of an ion current sensor, a cylinder pressure transducer, and an engine vibration sensor. Experiments are conducted on a four cylinder, turbocharged 4.5 liter diesel engine to determine the potential of using the ion current sensor to detect combustion resonance under different injection pressures and exhaust gas recirculation rates. It is concluded that the ion current signal can be used to determine the timing, amplitude, frequency, and duration of the resonance. The sensor output has the potential to be used as a feedback signal to the ECU (electronic control unit) to minimize engine vibration and noise.