Investigation of two stroke engine to improve the brake power and thermal efficiency through the mathematical modeling approach

Two stroke engines is comparatively small, simple in operation with less cost because of absence of valve mechanism. The performance of the engine is such that it has low brake thermal efficiency and higher exhaust emission because of incomplete combustion which results into high emission and fuel consumption. Scavenging is important for improvement of the engine performance by removing the exhaust gases from the engine. The paper details the modification in the engine for enhancing the scavenging process so that performance of engine in terms of brake power and thermal efficiency will increase. The modification in the two stroke engine is done by providing hole in transfer port for air aspiration. The general concept in using external air aided scavenging is to improve scavenging characteristics of base engine by reducing short-circuiting phenomenon. Investigation of the modified engine were done by evaluating the brake power and thermal efficiency of two stroke engine using the mathematical tools such as mathematical modeling, sensitivity and optimization. The paper highlights the modification in the engine to enhanced the performance of engine and the formulation of mathematical model. The formulated mathematical model predicts the performance of engine with the help of indices of each pie term formed with input variables. The positive indices of the pie term indicate the most influencing pie terms responsible for variation in the output variable such as brake power and thermal efficiency. The negative indices of the pie term indicate the inverse effect on the output variables as it is inversely proportional to the output variables brake power and thermal efficiency. Thus the exact mathematical model help to investigate the performance of the engine at lower cost with less time involved in experimentation.