Ion Current Detection During Cold Starting and Idling in Diesel Engines

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. 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. This presents a problem in the detection of the ion current signal in diesel engines, particularly during starting and idling operations. This paper investigates and addresses the ion current detection problems pertaining to cold starting and various idling speeds. Also, different approaches have been investigated to improve the signal detection under these conditions.