Ion current signal detection during cold starting and idling operation in a diesel engine.

摘要

Cold starting of diesel engines is characterized by inherent problems such as long cranking periods and combustion instability leading to an increase in fuel consumption and the emission of high concentrations of hydrocarbons which appear as white smoke. Accordingly, a signal indicative of combustion during cold starting and idling operation is important for combustion and emission control. The ion current signal has been considered for the feedback control of both gasoline and diesel engines. However, the ion current signal produced from the combustion of the heterogeneous charge in diesel engines is weaker compared to that produced from the combustion of the homogeneous charge in gasoline engines because of the lower combustion temperatures reached in diesel engines. Consequently, this presents a problem in the detection of the ion current signal in diesel engines, particularly during starting and idling operations. This research investigates and addresses the ion current detection problems pertaining to cold starting and idling at various speeds. Also, different approaches have been endeavored to improve the signal detection under these conditions so as to aid its application for misfire detection.