Techniques for Predicting Combustion Chamber Deposits in a Direct Injection Diesel Engine 2002-01-2673

The present study investigated three techniques for predicting combustion chamber deposit formation in a direct injection diesel engine. One non-intrusive technique, based on the factorial experimental design method was used to develop an empirical model. This model predicts deposit weight as a function of time, but is dependent on engine type, type of lubricating oil, and engine operating parameters. Two intrusive techniques were also investigated for predicting deposit formation: a fast response thermocouple and a deposit conductivity probe, both being located within the combustion chamber. It was shown that the fast response thermocouple technique provided a correlation between in-cylinder peak temperature phase lag and deposit thickness. The conductivity probe correlated electrical conductivity with deposit growth. As well, the waveform characteristics from the conductivity probe showed the potential to predict the physical structure of the deposits.