Measurement and analysis of ionization current signal in a single cylinder diesel engine

Diesel engines have made a lot of progress in the last few decades and engine electronic controls have played a big role in this success. This research presents a sensor for ion current in the cylinder and exhaust that can be used for feedback engine electronic control. This is an inexpensive on-board sensor that can be applied in multi cylinder engines.; Ionization current signal from a gasoline engine is very well understood and is measured using the spark plug. However, the ion current produced in diesel combustion has not been well investigated. In this work on a single cylinder diesel engine, the glow plug was modified to act as an ion sensor in addition to being a glow plug. This approach does not require any extra holes in the cylinder head of the engine.; In this study I investigated the ionization current in a diesel engine. The ion current has two peaks, the first peak occurs shortly after the peal of heat release and the second peak occurs later in the expansion stroke. The effect of speed and load on the magnitude and location of each of the two peaks has been determined. It has been concluded that the modified glow plug has been successful in producing the ion current signal. Also the two peaks were found to indicate the variations in engine speed and load.