THE EFFECTS OF SOME ENGINE VARIABLES ON MEASURED RATES OF AIR ENTRAINMENT AND HEAT RELEASE IN ADI (DIRECT INJECTION) DIESEL ENGINE

The rate of air flow into the flame and the heat release rate were thermodynamically calculated in a direct-injection diesel engine, and a two-zone model is proposed which uses three measured values of cylinder pressure, flame temperature, and injection rate as input data. Correlations between air flow and heat release rates under varied conditions show that combustion during early and main periods of diffusion combustion is controlled primarily by air flow into the flame, which increases with increased injection pressure. Higher swirl is also associated with increased air flow. The deep bowl piston has a higher air flow rate than the flat dish piston, and the flame's equivalence ratio becomes higher with increasing fuel amount. Advanced injection timing increases the air flow rate. Exhaust nitric oxide concentration is high and exhaust smoke density is low when the flame zone's mean equivalence ratio is low and the flame temperature is high.