1台工作20h的中型液压挖掘机样机在工地进行试验过程中,发动机空载时运转正常,一旦挖掘机进行挖掘作业,发动机即出现严重失速,且排气管瞬间排冒黑烟。刚出现失速时,仅发生在高速,随后中、低速也出现失速现象。最后出现严重失速、以致无法正常工作。分析认为,该机为样机,其液压系统存在故障的可能性很小,可能是燃油供油不足所致。 A 20h mid-sized hydraulic excavator prototype test at the construction site, the engine runs normally at no load, once the excavator excavation operation, the engine that a serious stall, and the exhaust pipe black smoke. Just appeared in the stall, only occurred in high speed, then medium and low speed also stall phenomenon. In the end there was a serious stall so that it did not work properly. Analysis, the aircraft as a prototype, the possibility of hydraulic system failure is small, may be caused by insufficient fuel supply.