During the operation of diesel engine, the speed suddenly exceeds the no-load speed greatly, and the speed cannot be reduced after the throttle is released. Accompanied by a huge noise and smoke, the engine is no longer under control. That is the "racing" problem of the diesel engine.

The bad effects caused by “racing” problem

Because of the huge mechanical force produced by "flying car", it is very easy to cause malignant accidents such as broken connecting rod or connecting rod bolt of engine and cylinder score. After exceeding its limit, serious accidents such as damages to cylinder block, connecting rod, crankshaft and piston, cylinder liner and cylinder head will occur, and even cause casualties. Therefore, urgent measures must be taken immediately to stop "racing" problem.

The causes of “racing”

(1) The fuel supply rod of the injection pump is stuck in the maximum fuel supply position.

(2) The oil supply tie rod is separated from the transmission plate, and the oil supply tie rod is out of control.

(3) The lubricate oil is added too much to the governor, or the oil level in the governor is too high due to oil leakage at the shoulder of the plunger sleeve.

(4) The failure of oil supply regulation due to the damage of speed regulating spring or plunger spring.

(5) The oil level in the air filter is so high that the lubricate oil is sucked into the cylinder.

(6) The preheating plug is damaged and diesel enters into the combustion chamber from the intake pipe.

The signs and teatments of "racing"

A．Cutting off the diesel supply is sensible in principle, but it doesn’t very effective in practice. Because when cut off the diesel supply, the diesel remained on the top of piston which cannot be burned perfectly is enough to keep burning for a period of time, the speed of the generator cannot be lowered.

B．Actually, cutting off the air supply is the most effective way. Without the oxygen in the air, the fuel cannot continue to burn. The method of cutting of air supply is different according to different engine structure. If there are decompression mechanisms, the engine should be decompressed immediately; If there are mechanical or pneumatic control of the intake and exhaust brake devices, pneumatic brake shall be applied immediately; If these mechanisms are not available, the tubular air intake or the engine intake should be blocked immediately. This method is used widely by many engineers.