LAUSR

Strategy of lean burn for reducing fuel consumption and emissions can be achieved by incorporating swirling motion in the incoming fluid entering the cylinder of the engine. In this backdrop, the application of shrouded intake valves gets the upper hand over the conventional poppet valve because of their capacity of producing intake-generated swirl flow. In the existing literature, a modified shrouded intake valve capable of producing significant amount of swirl with relatively smaller restriction to the incoming fluid has been reported. But, no work has been done to determine the effect of using modified shrouded intake valve in the emissions and performance of an SI engine. Thus, the effect of using the modified shrouded intake valve on the emissions and performance of an SI engine is studied and compared with that of poppet intake valve and 100°, 140°, and 180° shrouded intake valves. From the study, it is seen that the engine with modified shrouded intake valve produces lowest hydrocarbon and carbon monoxide emissions for maximum power condition, whereas the brake power, brake specific fuel consumption, and NOx emissions of the engine are quite close to the engine using poppet intake valve which is the best performing valve–engine combination for the same. For minimum brake specific fuel consumption condition, the engine with modified shrouded intake valve produces the highest brake power with the lowest brake specific fuel consumption, whereas the hydrocarbon and carbon monoxide emissions of the engine are similar to the engine using 180° shrouded intake valve which is the best performing valve–engine combination for the same.Graphical abstract