摘要：【中文】本发明涉及一种客车及其后保险杠组件，客车用后保险杠组件包括用于与舱门和舱体合围成后置发动机舱的后保险杠，所述后保险杠上设有用于连通后置发动机舱内外的泄流孔，所述后保险杠上对应于所述泄流孔布置有或泄流孔自身具有用于将后置发动机舱内的空气朝向客车尾部负压区域进行导向的导流结构。通过在后保险杠上开设泄流孔，能够在客车高速行驶时将后置发动机舱内的气流向后引出，减小后置发动机舱内的气流集聚而导致的气压阻力。由于客车在高速行驶时会在客车尾部形成负压区域，而导流结构可以将后置发动机舱内的空气朝该负压区域所在的方向进行导向，增加负压区域的气压值，减小负压拖拽力。 【EN】The invention relates to a passenger car and a rear bumper assembly thereof, wherein the rear bumper assembly for the passenger car comprises a rear bumper which is used for enclosing a rear engine compartment together with a cabin door and a cabin body, the rear bumper is provided with a discharge hole which is used for communicating the inside and the outside of the rear engine compartment, and the rear bumper is provided with a flow guide structure which is arranged corresponding to the discharge hole or is provided with a flow guide structure for guiding air in the rear engine compartment to a rear negative pressure area of the passenger car. The vent holes are formed in the rear bumper, so that air flow in the rear engine compartment can be led out backwards when the passenger car runs at a high speed, and air pressure resistance caused by air flow gathering in the rear engine compartment is reduced. Because the passenger train can form the negative pressure region at the passenger train afterbody when going at high speed, and the water conservancy diversion structure can lead the air in the rearmounted engine compartment towards the direction at this negative pressure region place, increases the atmospheric pressure value in negative pressure region, reduces the negative pressure and drags the power.