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1·The positive crankcase ventilation valve and gas caps with air-pollution control valves reduce volatile organic compound loss.

曲柄轴箱通风阀和配有废气帽的空气污染控制阀(的使用)对减少挥发性有机混合物释放有积极作用。

2·All automobile engines now built are equipped with the positive-crankcase ventilation system of crankcase emission control.

所有现代制造的汽车发动机，都需要装备控制曲轴箱有害污染的曲轴箱强制通风系统。