The
high water temperature of diesel generator set is mainly caused by the
following reasons:
First, the pump loses
its pumping effect. When the weather is cold, the cooling water left in the
pump body is not exhausted. The water between the impeller and the inner wall
of the pump body may freeze and expand, so that the impeller cannot rotate. After
the diesel engine is started, there is no cooling water circulation in the
cooling water channel, so that the temperature of the body rises quickly and
the water tank is “opened”. In addition, the pin of the fixed impeller is
broken or loosened, the water pump shaft rotates and the impeller does not
move, the water pump stops pumping water, the cooling water does not circulate,
and the water temperature is too high.
Second, the amount of
water in the cooling system is insufficient. Before the diesel engine starts,
there is no sufficient cooling water in the water tank, or the cooling system
leaks, the water supply of the pump is insufficient, or the water pipe and the
heat pipe are blocked by scale and dirt, which will cause insufficient cooling
water.
Third, the fan belt
slips or breaks, or the blades in the fan are twisted. In this case, the fan
belt is too loose and easy to slip, causing the speed of the water pump to
decrease, resulting in the cooling system water temperature is too high.
Fourth, the clearance
between the cylinder and the piston is too small. The clearance between the
cylinder liner and the piston is too small, the gap between the piston ring is
too small, the piston connecting rod group is not installed properly, and the
cylinder sleeve is poorly lubricated, which will cause the friction between the
piston group and the cylinder liner to increase, causing the working
temperature to rise, resulting in the cooling water temperature is high.
Fifth, the thermostat
failed. If the thermostat breaks and fails, when the water temperature is
higher than 70°C, the valve cannot be opened or the opening height is not
enough, so that the cooling water cannot be circulated through the radiator and
the water temperature is too high.
Sixth, the oil supply
time is too late. The oil supply is too late, the diesel combustion is not
complete, causing the diesel engine to overheat and the temperature of the
bottom surface of the cylinder head to rise, resulting in excessive water
temperature.
Fault
check judgement:
First, check the water
pump. Hold the outlet pipe of the cylinder head connected to the radiator by
hand. The idle speed is increased to the high speed. If the water flow is
increased, the pump is normal. Otherwise, the pump pump water pressure is
insufficient and should be dismantled. If the pin is broken or loose, the pump
shaft rotates and the impeller does not move, the pump stops pumping water. At
this time, the pump impeller pin should be replaced; if the pump impeller is
installed in reverse, the pump cannot pump water.
Second, check the
cooling water. Check if the cooling water is sufficient and check if the water
pipe and heat pipe are blocked before starting the diesel generator.
Third, check the fan
belt. If the belt is too loose, it should be adjusted; if the belt is worn too
much or broken, it should be replaced in time; if there are two belts, only one
of them is damaged, must be replaced with two new belts, and it should not be
used together with one old and one new. Otherwise, it will greatly shorten the
service life of the new belt.
Fourth, check the
clearance between the cylinder liner and the piston. Check if the clearance of
the piston ring is too small, and whether the cylinder liner lubricant is
sufficient. If it does not meet the requirements, replace the relevant parts.
Fifth, check the
thermostat. The engine is equipped with a thermostat, if there is a large
amount of water flowing out from the water inlet pipe of the water chamber of
the water tank, it means that the thermostat valve is not tightly closed or
damaged; if the water temperature greatly exceeds 70°C, the water inlet pipe of
the upper water chamber does not flow out or no large amount water flows out,
indicating that the thermostat is damaged or weakened.
Sixth, check if the fuel
supply advance angle is normal. Note: When the fuel injection advance angle is
not normal, the exhaust smoke colour of the diesel generator set will also be
abnormal.
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