Effect of tumble flap on combustion and performance of NA national engine

One of methods that has considerable effects on decrease of fuel consumption, is use of tumble flap in intake manifold of engine. Tumble flap with increasing tumble of air at inlet port of engine causes decrease duration of combustion and fuel consumption. In this research, effect of tumble flap with capability of changing angle of flap in inlet port on performance, duration of combustion of EF7 engine was investigated. First, with using of CFD, angle of flap on power, torque, CVVT effect, volumetric efficiency, spark time, thermal efficiency, duration of combustion, rate of increasing pressure, specific fuel consumption and indicated pressure versus engine speed were studied. Also, fuel consumption in NEDC cycle was considered. The result shows that with using of tumble flap, power of engine does not change, but duration of combustion decreases.