Aug. 10, 2021
As the auxiliary system of the diesel generator, the cooling system of Cummins diesel generator set plays an important role in ensuring the normal operation of the engine. It can keep the generator in a proper temperature range under all working conditions. Once the cooling system of Cummins diesel generator set fails, it will cause the unit to fail to operate normally, or even cause serious damage to the unit, users must pay attention to it. In this article, Cummins generator manufacturer introduces you in detail the common failures in the cooling system and the methods of inspection and judgment.
1. The amount of circulating water is scarce
Generally, the reason for the poor cooling effect of Cummins diesel engine is because the amount of cooling water is scarce, and the inability to continuously cool the diesel engine with cooling water will cause it to continuously heat up; the diesel engine overheats because the temperature of these media is too high. When the mechanical properties such as strength and toughness cannot reach the standard, the main heat load of the cylinder head, cylinder liner, piston assembly and valve will increase the deformation of the parts, reduce the matching gap between the parts, accelerate the wear of the parts, and even occur The phenomenon of cracks and stuck parts.
The engine oil with too high temperature causes the engine oil to deteriorate and its viscosity decreases. The internal parts of Cummins diesel engine that need to be lubricated cannot be effectively lubricated, causing abnormal wear. In addition, when the temperature of the diesel engine is too high, its combustion efficiency is reduced, causing the fuel injection nozzle to not work effectively and damaging the fuel injection nozzle.
Check and judge:
1) Before starting Cummins diesel generator, carefully check whether the coolant meets the requirements;
2) When Cummins diesel generators are running, pay attention to check for coolant leakage, such as radiators, water pumps, cylinder blocks, heater water tanks, water pipes, and rubber connecting hoses and water drain switches.
2. Low water supply efficiency of water pump
The abnormal operation of the water pump causes the water pressure to fail to meet the normal requirements, which will also reduce the flow of cooling circulating water. The flow of circulating cooling water depends on the energy provided by the operation of the water pump. The water pump continuously sends the cooling water to the radiator for cooling, and the cooled water is sent to the engine water jacket to cool the engine. When the water pump works abnormally, the pump energy provided by the water pump is insufficient to deliver the cooling water to the system in time, resulting in a reduction in the circulating water flow in the cooling system, resulting in poor heat dissipation of the system, and resulting in excessively high cooling water temperature.
Inspection and judgment: Hold the water outlet pipe connected to the radiator tightly with your hand, from idling to high speed, if you feel that the flow of circulating water continues to increase, it is considered that the pump is operating normally. Otherwise, it means that the pump is operating abnormally and should be overhauled.
3. Scaling and blockage of the circulation system pipeline
Circulation system pipe fouling is mainly concentrated in radiators, cylinders, and water jackets. When the deposited scale accumulates too much, the cooling water's heat dissipation function will decrease, leading to an increase in water temperature. The main components of scale are calcium carbonate and magnesium carbonate, which have poor heat transfer capabilities. The scale deposits adhere to the circulation system, which seriously affects the heat dissipation in the engine. The serious situation causes the blockage of the circulation pipeline, which causes the blockage of the circulating water volume, reduces the ability to absorb heat, and causes the cooling water temperature to be too high. Especially when the added water is hard water containing a large amount of calcium and magnesium ions, the pipes will be blocked and the cooling circulation system will work abnormally.
4. Thermostat failure
The thermostat is a valve that controls the flow path of the engine coolant, and is a kind of automatic temperature adjustment device. The thermostat is installed in the combustion chamber of the engine to control the temperature of the combustion chamber.
The thermostat must be at the specified temperature. Fully open is helpful for small circulation. If there is no thermostat, the coolant cannot maintain the circulating temperature, and a low temperature alarm may be generated. In order to ensure that the engine can reach the normal operating temperature as soon as possible after starting, the engine uses a thermostat to automatically control the circulation of the cooling water. When the temperature is higher than the normal operating temperature, the main valve of the thermostat opens, allowing the circulating cooling water to flow through the radiator to dissipate heat. When the thermostat is damaged, the main valve cannot be opened normally, and the cooling circulating water cannot flow into the radiator for heat dissipation. Local small circulation causes the water temperature to be too high.
Inspection and judgment: At the beginning of engine operation, the circulating water temperature rises rapidly; when the water temperature value on the control panel indicates 80°C, the heating rate slows down. After 30 minutes of operation, the water temperature is basically around 82°C, and the thermostat is deemed to be working normally. On the contrary, when the water temperature keeps rising after it rises to 80°C, the temperature rises quickly. When the water pressure in the circulation system reaches a certain level, the boiling water suddenly overflows, which indicates that the main valve is stuck and suddenly opened. When the water temperature gauge indicates 70°C-80°C, open the radiator cover and the radiator water release switch, and feel the water temperature with your hands. If they are hot, the thermostat is working normally; if the water temperature at the water inlet of the radiator is low and the radiator is filled with water There is no water or very little water flowing out of the water inlet pipe of the chamber, indicating that the main valve of the thermostat cannot be opened.
5. The fan belt slips, cracks or the fan blade is damaged
Long-term operation will cause the fan belt of Cummins generator set to slip, and the speed of the water pump will decrease, causing the cooling system water temperature to be too high.
Check the fan belt. When the belt is too loose, it should be adjusted; if the belt is worn or broken, it should be replaced immediately; if there are two belts, only one of them is damaged, and two new belts must be replaced at the same time, not one old and one new Used together, otherwise it will greatly shorten the service life of the new belt.
From the Dingbo Power’s kind reminder is that when using Cummins diesel generator sets, users should perform regular maintenance on the generator sets in order to discover hidden troubles in time and overhaul them in time. If you have any questions, please call Dingbo Power for consultation. We are always committed to providing customers with comprehensive and considerate one-stop diesel generator set solutions. Please feel free to contact us directly at email@example.com.
Sep. 09, 2022
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