The engine overheats. Generally speaking, the temperature of the cooling water in the body is too high. There are two common causes of motor overheating, namely decreased heat dissipation capacity and excessive heat load.
The reasons for the decrease in heat dissipation capacity are:
(1) Insufficient cooling water Cooling water is the heat carrier in the heat circulation system. cooling, which means that the heat dissipation that needs to be removed from the motor body is It is carried away and dispersed by the water carrier. If the coolant in the cooling system is reduced due to leakage or evaporation, the heat naturally removed from the body will be reduced, causing excessive heat build-up in the engine, which corresponds to overheating of the engine. engine. The main reasons for reducing cooling wateridition are the following two points:
① Water leakage in the cooling system is mainly caused by damage to the hydraulic seal of the water pump, pipe rupture or loose seal. connection, water leakage due to damage to the radiator and damage to the drain switch or it is not closed tightly, heating equipment is leaking, etc., which will cause the cooling water in the cooling system, thus causing the engine. overheat.
② The water in the evaporative cooling system evaporates under the influence of temperature, which will also reduce the cooling water in the system. If the recharge is not timely, the result will be the same as above.
(2) Poor heat dissipation
① Effects of the radiator: After using the radiator for a long time, the scale inside the radiator will thicken accordingly. Since tartar haslow heat transfer capabilities, it will lead to poor heat dissipation.
Radiator vent is blocked Due to fan action when the engine is running, dust flows through the radiator with the air. When dust adheres to the flat tubes and fins of the radiator, not only the air circulation cross section of the radiator is reduced, but also the heat conduction capacity is too low due to dust and dirt, which which leads to poor heat dissipation.
②The cooling intensity of fan belt sliding in water cooling system depends on the fan speed. If the fan drive belt is too loose and slips, the power transmission efficiency will not decrease. only reduce the fan speed, but also reduce the cooling efficiency. The resistance ofdecreases, and at the same time, the speed of the water pump also decreases and the displacement decreases, which makes the cooling water flow slowly and cannot discharge heat quickly, i.e. poor heat dissipation.
③Influence of the cooling intensity adjustment device The dampers and the thermostat are cooling intensity adjustment devices. If the cooling intensity adjuster fails or malfunctions, the engine temperature will be too high.
The louvers are located in front of the radiator and allow the ventilation flow of the radiator to be adjusted. When the opening is large, the ventilation volume is large, and conversely when the opening is small, the ventilation. the volume is small. When the dampers are not opened, the cooling air has a smaller circulation cross-section, which leads to an increase in temperatureof the motor.
The thermostat is damaged. The thermostat is located at the engine water outlet. Its function is to adjust the cooling intensity, that is, when the engine temperature is low, it will cut off the large circulating water path and connect the small circulating water path to reduce the heat. dissipation and quickly raise the engine temperature; the engine temperature rises to When the temperature is specified, the thermostat connects the large circulating water path and closes the small circulating water path. If the thermostat is damaged and cannot connect the large circulating water circuit, resulting in poor circulation of cooling water, the heat absorbed by the cooling water cannot be transported to the radiator to be evacuated and the engine overheats.
④ The cooling water freezes When working in winter, the temperature of the cooling water in theThe radiator water chamber is very low and easy to freeze. When frozen, the cooling water does not circulate, making the temperature of the cooling water too high.
The reasons for excessive thermal load are:
(1) The diesel engine runs erratically due to the long waiting time after ignition, the significant fuel injection and. sufficient combustion preparation. Once it catches fire, the flame spreads quickly everywhere, the burning speed is fast, and the pressure rise rate increases, causing difficult work. Due to the rough operation of the diesel engine, the heat transfer from the gas to the cylinder head and cylinder wall increases, which increases the temperature of the cylinder and other parts as well as the cooling water, causing the overheating of the engine.
(2) The injection time is too late and the injection advance angle is too small.Most of the combustion process is shifted to the work of expansion, the volume above the piston increases, and the contact area between the piston is increased. The flame and the cylinder wall increase. The heat absorbed also increases, thereby reducing the thermal efficiency utilization rate, increasing the temperature of the exhaust gas, and increasing the heat transferred to the cooling water.
(3) Carbon deposits: When there are a lot of carbon deposits in the engine's combustion chamber, heat builds up, which also explains why the water temperature cooling rate is too high.
(4) The motor assembly is too tight. Because the motor assembly is too tight, the friction resistance is very large when the motor is running, and the heat generated increases when heat is transferred to the motor. cooling system, the thermal load of the cooling system hasincreases, so the engine temperature is too high.
(5) Improper operation: Construction machines often operate under heavy load and the ambient temperature is also high. This not only increases the thermal load on the cooling system, but also reduces the heat exchange rate of the system. cooling system due to high ambient temperature. Deterioration (poor cooling effect), causing the engine temperature to be too high.
2. Solution:
(1) If the cooling water temperature is normal when the diesel engine is under normal load, but when the heavy load running time is too long, the temperature of the cooling water is obviously too high, indicating that the engine overheating is caused by prolonged operation of the engine, caused by heavy workload, you should take proper restt.
(2) If the engine often operates under harsh working conditions, this is also the cause of engine overheating. The reason for the rough operation of the engine must be identified and eliminated in a targeted manner.
(3) If the engine is weak when running, the sound is muffled, the cooling water temperature is high, and the exhaust pipe temperature is abnormally high, it means that Engine overheating is mainly caused by the injection advance angle being too small, it should be treated as diesel. The fuel injection time is adjusted according to the method mentioned by the fuel system.
(4) Observe the ventilation condition of the radiator. If the shutter in front of the radiator is not open or there is too much scale on the radiator, this indicates that the cause is mainly due to engine overheating and needs to be treated.
(5) Observe whether the coolantment in the cooling system is sufficient. If there is water leakage in the appearance, it indicates that the engine overheating is caused by water leakage, and the water leakage should be eliminated; If there is no water leak, open the radiator water cap and observe the adequacy of the cooling water. If the cooling water is seriously insufficient, this is usually due to engine overheating because the cooling water has not been replenished for a long time. and it should be restocked.
(6) Check the tightness of the fan beltWhen the motor stops running, move the fan blades by hand. If the fan can slip, it means that the fan belt is too loose, which is the cause of poor heat dissipation and needs to be adjusted. By adjusting the belt tensioning device, such as a generator or a special tension pulley, the belt can atincrease the pretension force. The inspection standard is: use your thumb to press 29-49N (3-5kg) between the generator and the fan wheel. . It is advisable to press the belt with a force of 10 to 20 degrees.
(7) Check the radiator for scale. Observe the scale in the radiator from the radiator water inlet. If there is indeed scale, this means that the scale is causing poor heat dissipation and overheating of the motor, and must be removed. Disposal method: Put a certain amount of descaler into the cooling water, let the engine run for 24 hours, then drain the water and replace it. If the cooling effect is improved, the same method needs to be repeated several times (but it does). rubber parts that are easy to corrode).
(8) Check the thermostat. Pay attention to temperature increase after initial engine start. Ifthe water temperature rises quickly, it means that the thermostat is damaged and the engine overheats, and the thermostat needs to be replaced.
(9) If the above inspections are normal, it means That the engine overheats is caused by excessive carbon deposits in the combustion chamber. If this occurs, it must be dismantled and identified, and the carbon deposits must be removed.
(10) If the water temperature rises suddenly when the engine is running in winter, this is mainly due to the freezing of the cooling water in the radiator water chamber, which must be heated to solve the problem.
Why is there a spark when the engine is off and hits the generator?
Overheating failure of the diesel generator set during operation will not only lead to a decrease in the power of the generator set, but also leave hidden dangers of unit breakdown. DIn severe cases, sudden failures such as cylinder pulling, cylinder jamming, tile burning, and piston top burning may occur. Therefore, users should take this situation seriously when they encounter it.
Manager Li of the after-sales service department of Shandong Huaquan Power Co., Ltd. analyzed that there are two main reasons for the overheating of diesel generator sets: firstly, the blocking of heat dissipation, cooling, and lubrication systems cause the diesel engine to overheat; the second cools. The system and lubricating oil system leaked, causing the unit to overheat.
A. Blockage of heat dissipation, cooling and lubrication systems, leading to overheating of the unit
1) Blockage of the radiator or pipeline. Once the radiator and pipes are clogged and watercooling can no longer circulate, the diesel generator set will overheat.
2) The exhaust pipe is blocked. When the exhaust pipe is blocked, when the diesel generator set is working, the exhaust gas is not discharged smoothly, and part of the exhaust gas remains in the cylinder in the next intake stroke, because it there is more exhaust gas in the cylinder. bottle, oil and fresh gas. The mixture cannot penetrate completely. When the spark plug ignites, the flame spreads and burns slowly, burning for a long time, forming afterburner. Parts in contact with gas have a long combustion time and cannot release heat, causing overheating. At the same time, due to the obstruction of the exhaust gas discharge, the exhaust gas temperature increases significantly during exhaust and the heat load of the assembly. the unitincreases, causing the generator set to overheat.
3) The oil filter is clogged. Under normal circumstances, the engine oil of the diesel generator set enters the diesel engine through the oil filter. Once the oil filter is clogged, oil can only enter the various lubrication points of the diesel engine through the bypass passage. In this way, because the oil has not been filtered, it can easily block the oil pipeline, causing poor lubrication. The oil pipeline is blocked and the heat generated by the friction coupling cannot be dissipated, causing the generator set to overheat.
4) The oil filter is clogged. The oil filter is placed at the inlet of the oil suction device in the oil pan to remove foam and prevent larger impurities from entering the oil pump. Once the oil filter is clogged and the supply of lubricating oil to the EL unitdiesel generator is interrupted, dry friction will occur in the friction couplings of the unit, causing the generator set to overheat.
B. The cooling system and lubricating oil system are leaking, causing the unit to overheat.
1) The radiator or pipeline is leaking. If the radiator or pipeline leaks, the generator set will overheat due to the limited water storage capacity of the diesel engine's water tank.
2) Leaks from the oil pan or oil pump. Oil pan or oil pump leaks are mainly caused by a loose oil drain plug or damaged gasket. The consequences of a leaking oil pan or oil pump are reduced or interrupted oil supply to the diesel generator set. Since the unit reduces the cooling effect of the engine oil, the heat from the friction pairs of the diesel generator set cannott not be evacuated, resulting in overheating of the unit.
Reference website: www.comler.cn
1. Going to the corresponding repair shop to repair and replace engine oil is the most common part of maintenance. Engine oil plays a role in. engine lubrication, cooling, damping and reduction of wear. Engine oil has a shelf life, so it must be replaced regularly. Different types of engine oil have different replacement cycles. Currently, there are three types of motor oil: Full synthetic motor. engine oil and semi-synthetic engine oil and mineral oil. Full synthetic motor oil has better high and low temperature types, and its price is also the highest of the three. The replacement cycle is usually 10,000 to 12,000 kilometers. The replacement interval for semi-synthetic engine oil is 8,000-10,000 kilometers. The oil mMineral engine is generally replaced every 5,000 kilometers.
2. The engine has heavy carbon deposits.
The most common cause of car vibration is that the throttle valve is too dirty or the fuel injection nozzle has too many deposits of carbon. When there is too much carbon deposit inside the engine, the gasoline ejected from the cold start fuel injection head will be absorbed by the carbon deposit, making the cold start mixture too fluid, which will make it difficult to start. The only way is to wait until the gasoline is absorbed by the carbon deposits. When the car is saturated, it is easier to start the car. Once the car is started, gasoline adsorbed on carbon deposits will be sucked into the cylinder by engine vacuum. suction for combustion, which will also make the mixture richer. The engine's combustible mixture is sometimes fluidand sometimes rich, resulting in vibration at idle.
3.. Ignition system problems
Check the operating conditions of the spark plugs, high voltage wires and ignition coils. Poor operating conditions of the ignition system and spark plugs can also be the cause. this type of failure.
4. Oil pressure is unstable
If you have cleaned the carbon deposits from the engine, washed the throttle, replaced the spark plug, etc., and still find that the body shakes when idling , it is recommendedCheck whether the fuel supply pressure and manifold pressure sensor are normal. If the fuel supply pressure of the fuel pump is abnormal or the manifold pressure sensor has an incorrect value or malfunction, it will cause vibration in the vehicle body.