Some Techniques to Improve Performance of Si Engine At Part Loads - A Numerical and Experimental Approach
Work in this paper involves the computer simulation and experimental investigations on a single-cylinder, four-stroke, spark-ignition engine in which inlet valve closure timing and clearance volume are optimized for better part -load performance. The simulation procedure involves thermodynamic and global modeling techniques. Many sub-models have been used for predicting heat transfer, friction and gas exchange processes. A two-zone model is adopted for combustion process. The combustion model used here predicts mass burning rates, ignition delay and combustion duration, etc. Sub-models for calculating flame-front area, flame -speed and chemical equilibrium composition of ten product species are used in combustion analysis. Measured valve -displacement along with suitable coefficient of discharge is used in the analysis of gas exchange processes. Unburned hydrocarbons and carbon monoxide emissions have been predicted.