进气道型式对四气门汽油机进气流动特性的影响

在稳流气道试验台上，研究了四气门汽油机整体式和分体式进气道进气流通特性及产生的缸内滚流特性，提出了进气不均匀度和进气终了滚流比不均匀度的概念．发现四气门汽油机各缸产生的最大滚流轴线与曲轴轴线夹角是不同的．整体式进气道流通系数和平均流通系数大于分体式进气道．分体式进气道进气终了滚流比大于整体式进气道，平均进气终了滚流比增加7％．分体式进气道进气不均匀度小于整体式进气道，而进气终了滚流比不均匀度则大于整体式进气道．

Effect of Intake Port Type on Intake Flow Characteristics in a Four-Valve Gasoline Engine

The intake flow characteristics of engine cylinder head equipped with integrated and separated intake ports are measured on steady flow rig, the tumble characteristics generated by two intake ports are also analyzed. The intake asymmetry and tumble ratio asymmetry at the end of induction stroke are put forward. The results show that the angle between maximum tumble axis and crank axis generated by each cylinder in a four-valve gasoline engine varies. The flow coefficient and mean flow coefficient of engine cylinder head equipped with the integrated intake port are larger than that with separated intake port. The tumble ratio at the end .of induction stroke in the engine equipped with separated intake port is larger than that equipped with integrated intake port, the mean tumble ratio at the end of induction stroke of engine cylinder head equipped with separated intake port increases by 7% compared with the integrated intake port. The mean intake asymmetry of engine cylinder head equipped with separated intake port is smaller than that equipped with integrated intake port, while the mean tumble ratio asymmetry at the end of induction stroke is larger than that equipped with integrated intake port.