Views: 33 Author: Site Editor Publish Time: 2023-03-20 Origin: Site
Common fault in the use of diesel engine
During the use of diesel engines, there will be more or less various problems, among which the impact of insufficient power is relatively large. Insufficient power can be divided into many aspects. In this regard, the technical staff of Shanghai Dongfeng Diesel Engine Research Institute analyzed the reasons affecting the insufficient power of diesel engines and proposed solutions.
1. Fuel system failure: The power or speed of the engine still cannot be increased even after the engine is accelerated.
1). Air enters or is blocked in the fuel filter or pipeline, resulting in unsmooth oil passage, insufficient power, and even difficulty in igniting. The air entering the pipeline should be removed, the diesel filter element should be cleaned, and the fuel filter element should be replaced if necessary.
2). Insufficient fuel supply of fuel injection pump
It should be checked in time, or repaired and replaced, and the oil supply of the oil supply pump should be readjusted.
3). Poor atomization of the injector or low injection pressure
Damage to the fuel injection parts can cause oil leakage, seizure or poor atomization. At this time, it is easy to cause lack of cylinders and insufficient engine power. The injector should be cleaned, ground or replaced in time.
2. Faults in the intake and exhaust systems: the exhaust temperature is higher than normal, and the smoke color is poor.
1). The air filter is blocked
A dirty air filter will cause increased blocking and reduced air flow, resulting in underpowered engines. Clean the air filter element or remove the dust on the paper filter element as required, replace the filter element if necessary and check whether the oil level is normal.
2). The exhaust pipe is blocked or the connecting pipe is too long, the turning radius is too small, and there are too many elbows
The carbon deposit in the exhaust pipe should be removed: reinstall the exhaust pipe, there should be no more than three elbows, and there should be a large enough exhaust section.
3. Changes in fuel injection advance angle or intake and exhaust phase: poor performance at each gear speed
If the oil supply advance angle is too large or too small, the fuel injection time of the oil pump will be too early or too late. If the fuel injection time is too early, the fuel will not burn fully, if it is too late, white smoke will appear, and the fuel will not burn sufficiently. Make the combustion process not in the best condition. At this time, check whether the screw of the fuel injection transmission shaft adapter is loose. If it is loose, adjust the fuel supply advance angle according to the requirements and tighten the screw.
4. The diesel engine is overheated and the ambient temperature is too high: the temperature of the engine oil and cooling water is very high, and the exhaust temperature is also greatly increased
The overheating of the diesel engine is caused by the failure of the cooling or lubrication system. In this case, the water temperature and oil temperature will be too high, and it is easy to cause cylinder scuffing or piston ring jamming. When the exhaust temperature of the diesel engine increases, check the cooler and radiator, remove scale, and check whether the pipe diameter is too small. If the ambient temperature is too high, ventilation should be improved and cooling measures should be strengthened temporarily.
Cylinder head component failure: At this time, not only the power is insufficient, but also the performance is degraded, and there is air leakage, black smoke from the intake pipe, and abnormal knocking sounds, etc.
1). There is air leakage at the joint surface between the cylinder head and the body, and general airflow rushes out from the liner when the speed is changed: the large stud nut of the cylinder head is loose or the liner is damaged.
Check Big Stud Nuts
Check the cylinder head gasket
2). Inlet and exhaust valve leaks.
Insufficient air intake due to exhaust air leakage or exhaust gas mixed in the intake air will result in insufficient fuel combustion and reduced power. The mating surface of the valve and the valve seat should be ground to improve its sealing performance, and replaced if necessary.
Valve and valve seat mating surface
3). The valve spring is damaged
Damage to the valve spring will cause difficulty in valve return, valve leakage, and reduced gas compression ratio, resulting in insufficient engine power. Damaged valve springs should be replaced in time.
4). Incorrect valve clearance
Incorrect valve clearance can cause air leakage, resulting in reduced engine power and even difficulty in igniting. The valve clearance should be readjusted to the specified value.
5). Air leakage in the injector hole or damage to its copper gasket: the piston ring is stuck, the valve stem is biting, causing insufficient cylinder compression pressure
Leakage of the fuel injector installation hole or damage to the copper pad will cause lack of cylinders and insufficient engine power. It should be dismantled for inspection and damaged parts replaced. If the inlet water temperature is too low, it will lead to increased heat dissipation loss. At this time, the inlet temperature should be adjusted to meet the specified value.
5. The surface of the connecting rod bearing bush and the crankshaft connecting rod journal is bitten
This situation will be accompanied by abnormal sound and oil pressure drop, which is caused by blocked oil passage, damaged oil pump, blocked oil filter element, or low oil hydraulic pressure or even no oil. At this time, the side cover of the diesel engine can be removed, and the side clearance of the big end of the connecting rod can be checked to see if the big end of the connecting rod can move forward and backward.
For a supercharged diesel engine, in addition to the above reasons that will reduce the power, if the supercharger bearing wears, the intake pipe of the compressor and the turbine is blocked by dirt or leaks, the power of the diesel engine can also be reduced. When the above situation occurs in the supercharger, the bearings should be repaired or replaced separately, the intake pipe and casing should be cleaned, the impeller should be cleaned, and the joint surface nuts and clamps should be tightened.