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一、为何发出“嗵嗵”声 一台上海—50型拖拉机,作业时,空气滤清器内发出“嗵嗵”的敲击声,检查后发现供油时间过晚,上止点后20度才开始供油。按要求,上海—50型拖拉机的供油提前角为上止点前25度～27度,而实际供油提前角已推迟到45度～47度。这样,排气终了时气缸内余压太高,故进气门开启时,便有一股废气从进气门窜出,造成空气滤清器内发出“嗵嗵”的敲击声。重新调整供油提前角后,响声消失。
One, why issue a “嗵 嗵” sound A Shanghai -50 tractor, operation, the air filter issued a “嗵 嗵” percussion sound, check and found that the fuel supply time is too late, 20 points after the top dead center Only then began to supply oil. According to the requirement, the fuel supply advance angle of Shanghai -50 tractor is 25 degrees ~ 27 degrees before the top dead center, while the actual oil supply advance angle has been postponed to 45 degrees ~ 47 degrees. In this way, the exhaust end of the cylinder residual pressure is too high, so the intake valve is open, there is an exhaust from the intake valve sprang, causing the air filter issued a “嗵 嗵” percussion. After adjusting the fuel supply advance angle, the sound disappears.