Modeling and Parameter Identification of Spark Plug Deposit Formation Mechanism for Different Fuel/Lubricant Combination

Abstract

The identification of model parameters is complex and requires many approximations and laboratory investigations. Here, a novel approach of identifying these parameters is proposed, that uses experimental data, and a parameter estimation method to minimize a cost function made up of errors between the predicted and experimental deposit thickness. The parameters are identified for different gasoline-ethanol blends and lubricants. Concomitantly, the study of thermal and electrical properties of deposits is done, which along with the identified parameters are used to extract information about the possible sources, mechanisms and other factors that will affect deposit formation on the spark plug and its characteristics. It is found that the deposit formation model along with the identified parameters has the potential to reliably estimate the deposit growth with time as good correlations have been observed between measured and predicted spark plug deposit mass for all fuels and lubricants. The thermal and electrical conductivity of spark plug deposit increases with high ethanol fraction and high viscous oil that consequence in increased chances of side sparking.