Reduction of Exhaust Gas Emission in a SI Two Stroke Engine with Direct Fuel Mixture Injection

Recently in order to decrease of the exhaust emission and fuel consumption in the modern small SI two-stroke engines a direct fuel injection is applied or a rich fuel mixture is delivered directly to the cylinder. In order to increase the time required to vaporize all injected fuel and create a stratified charge with the rich mixture near the spark plug, a new concept of preparation and injection of the fuel mixture was analysed and tested. This paper includes a short description of the system shown in enclosed figures, the mathematical model of the charge exchange in the chamber and the cylinder and also the model of fuel vaporization in the chamber. The main aim of the paper was a comparison of the thermodynamic parameters especially the emission of CO, HC and CO₂ obtained from experimental tests and from a simulation process in KIVA program for the standard carburetted engine and the engine with proposed system at some rotational speeds and control configurations.