Effect of intake port tumble ratio on engine pressure rise rate and noise
Taking a certain dual injection 6-cylinder engine as the research object,two types of intake ducts with higher and lower tumble ratio are designed.The cylinder flow field is simulated using the three-dimensional computational fluid dynamics software AVL Fire,the combustion characteristics of the engine is analyzed,and bench combustion tests and noise tests are conducted.The simulation results show that under the condition of a speed of 2 800 r/min and an average effective pressure of 1.3 MPa,compared with the higher tumble ratio scheme,the first and second peak tumble ratios in the cylinder of the lower tumble flow scheme are reduced by 44.3%and 34.9%,the maximum average cylinder pressure is reduced by 544 kPa,and the maximum pressure rise rate is reduced by 16.84%.The bench test results show that the combustion duration of the two intake ducts is not significantly different.Compared with the higher tumble ratio scheme,the tumble ratio scheme has a combustion center of gravity delayed by 2.02° in terms of crankshaft angle,an increase in fuel consumption rate of 0.67%,a decrease in pressure rise rate of 19.87%,and a reduction of about 6.0 dB in engine noise at frequencies of 700-1 300 Hz.The noise improvement effect is significant.
NETL
NSTL
万方数据
