Numerical investigation of the effect of advance ignition timing on combustion process in direct injection rotary engine fueled with biodiesel.

Biodiesel is a clean energy source that helps in the reduction of environmental pollution as compared to fossil fuel. This study aimed to improve the performance of combustion and reduce emission in direct injection rotary engine by fueling it with biodiesel as well as selecting the best ignition time. A 3D‐dynamic simulation model was established and then coupled with biodiesel chemical kinetics mechanism. On this basis, investigation of five ignition timings (IT) was conducted to know their various effects on combustion process. The simulation results showed that properly advancing IT increased in‐cylinder pressure, with the peak pressure (Pmax) of 35°CA (BTDC) IT of 45.99 bar the largest. Comparing IT of 35°CA (BTDC) with the IT of the original engine showed an 18.14% increase in peak pressure. The corresponding crank angle (φmax) for Pmax values also proved that when the IT was advanced, φmax values decreased and that of 35°CA (BTDC)‐10.37°CA (ATDC), 30°CA (BTDC)‐11.46°CA (ATDC), and 25°CA (BTDC)‐13.88°CA (ATDC) were better because they were generally between 10–15°CA (ATDC), which contributes to better engine performance. With advanced IT, phase of total period during combustion was continuously brought forward due to flame propagation acceleration by tumble as well as increase of tumble residence effect time that aided in improving the combustion rate. The burnt fuel mass fractions at TDC of 40°CA (BTDC) IT of 0.94 was the highest followed by 35°CA (BTDC) IT of 0.88. Under this computational condition, 35°CA (BTDC) was deemed to be the improved combustion scheme though soot exhaust increased. [ABSTRACT FROM AUTHOR]