Numerical investigation on effect of thermally isolated piston on improvingSI engine performance during the cold start conditions

In low ambient temperatures, the engine will have poor output torque andpower generation at the first cycles of its performance, long start time andhuge noxious emissions because of insufficient temperature and quality of airfuelmixture and failure of flame to burn the charge. It is noted that anyattempt to increase the charge temperature leads to better combustionconditions. By applying thin ceramic coating over the piston top surface andincreasing the temperature of engine inner walls, more efficient combustionin shorter time can be provided for the engine. In current research, a transientthermal study is developed for simulating the engine performance under coldstarting conditions and predicting the effect of insulating layer thickness onthe charge temperature before ignition timing. The results demonstrate thatthe ceramic coating can provide higher temperature for piston crown andeffectively improve the temperature of charge during the first cranking cyclesof engine cold start stage.

Keywords:

Cold start , Thermal analysis , Spark Ignition Engine , Ceramic layer , Finite element method ,