Diesel generator set maintenance training diesel article -p151-p155

Diesel generator set maintenance training diesel article -p151-p155

Fault 7: The diesel generator set diesel engine suddenly heard a rhythmic, crisp metal knocking sound in the cylinder and saw the exhaust pipe discharge a large amount of blue smoke.

Failure analysis:

This failure is generally due to premature injection. When the diesel engine is in operation, premature injection of fuel will cause diesel fuel to be injected into the combustion chamber under low temperature and pressure, which will prolong the diesel ignition time and accumulate more diesel in the combustion chamber. If diesel is burned at this time, the temperature and pressure in the combustion chamber will rise sharply, causing metal knocking in the cylinder. To distinguish whether the diesel injection time during operation is too early, there are two characteristics of the sound; one is that the diesel engine emits a sharp, crisp, continuous metal-like knocking sound when the diesel engine accelerates rapidly; the other is an idle or small load plant. During work, the knocking sound is obvious and the organism vibrates. When the load is large, the sound is relatively reduced and the operation is relatively stable.

Method of exclusion.

The troubleshooting method is as follows:

1 Remove the high pressure tubing of the high pressure oil pump, as shown in Figure 4-l.

2 Lock the governor handle at the maximum fuel supply of the diesel engine, as shown in Figure 4-2.

2 Turn the crankshaft according to the running direction of the diesel engine and observe the oil supply of the high pressure oil pump during the rotation. When it is found that the oil level of the first cylinder has just fluctuate, the crankshaft is stopped.

4 Loosen the captive screws on the high pressure pump drive shaft adapter plate.

5 According to the direction of rotation of the diesel engine, pull the diesel flywheel downwards from the upper end of the oil monitoring port with a flat-knife thread cutter. When the pointer on the flywheel housing is aligned with the 28° mark on the flywheel, tighten the two on the splice tray. Screw is the Secretary.

When adjusting the injection advance angle, the fuel supply system must be filled with fuel, otherwise there will be a certain error in the adjustment of the advance angle of the spray. Note that the fuel supply advance angles for different types of diesel engines may be different, and generally should be adjusted according to the requirements of the machine's technical specifications.

Fault 8: A small amount of milky bubbles appeared during the operation of the diesel generator set diesel engine.

Failure analysis:

It was found that there was a small amount of air bubbles in the vicinity of the fourth cylinder intake and exhaust valves of the cylinder head.

This type of failure is generally due to the fact that after the cylinder head is damaged, the cooling water in the water channel inside the cylinder head is mixed with the oil that cures the rocker arm.

Method of exclusion:

1After the diesel engine stops rotating, use fine cotton yarn to detect the deteriorating oil at the intake and exhaust valves, and then start the diesel engine to 800r/min to observe if there is any deterioration engine oil.
If it is found that there is still white spoilage engine oil overflowing from the intake and exhaust valves, it indicates that there is a crack in the position where the cylinder head is exposed to white air bubbles, and the oscillating assembly at the upper part of the combined cylinder head should be removed, as shown in Figure 5-19. Show.

2 Disassemble the combined cylinder head from the outside in the diagonal order. After removing the cylinder head from the airframe, replace the aR cylinder head and remove the fault. Note: Before assembling the new cylinder head, grind the valve and seal the valve, then install the cylinder head in the order from the inside out.

Fault 9: diesel generator set diesel engine during operation, found high temperature oil pump temperature is too high fault analysis diesel engine in the high-speed operation process, high pressure oil pump high temperature fault is generally due to the lack of oil inside the high pressure oil pump and governor, the various lubrication components Without sufficient lubrication, the frictional resistance of moving parts increases and heat is generated. Other reasons are: stuck in the plunger of the high-pressure pump: the high temperature of the engine caused the temperature of the high-pressure pump to be too high: the oil hole in the injector of the injector is blocked and the part of the diesel that is ejected by the high-pressure pump Return to the high pressure pump, this will also make the high pressure pump generate heat.

Method of exclusion

1 Check the oil in the high pressure oil pump and governor, as shown in Figure 5-18. It is required that the amount of oil in the high pressure pump should be able to reach the second scale of the oil scale. The amount of oil in the governor should reach the oil level screw. If the amount of oil does not meet the requirements, it should be filled as required; if the amount of oil meets the requirements, the next inspection should be carried out.

2 Open the high-pressure pump side cover, and use a flat-head screwdriver to slid each plunger (as shown in Figure 5-2), and observe whether the plunger is stuck during oil supply. If there is stuck phenomenon, the high-pressure oil pump should be removed and sent to a high-pressure oil pump repair center for repair.

Fault 10: After the diesel generator set's diesel engine started to the rated speed, it was found that the fault occurred at the oil outlet and the fault occurred.

This failure is usually caused by a cylinder leak.

Method of exclusion:

The cylinder pressure gauge is used to detect the pressure of four cylinders, as shown in Figure 2-34. If the detected value is different from the value specified in the specification, it indicates that the cylinder is leaking. The cylinder head of the cylinder should be removed and the piston rod assembly removed. Check whether the piston ring and the inner wall of the cylinder liner are damaged. The damaged parts should be replaced. If the pressure in the four cylinders is low, the diesel engine should be overhauled and all the damaged parts replaced.

Fault 11: After the diesel generator diesel engine starts, there is an abnormal noise in the valve chamber a shell, the sound is also louder, and there is a heavy knocking sound of the wife in the cylinder.

Failure analysis:

The door gap is too large; the wear gap between the valve stem and the valve guide is too large; wear is serious; the valve spring is broken: the feed valve advance angle is too small.

Method of exclusion:

1 Remove the valve housing of the diesel engine and inspect and adjust the valve clearance.

Valve stuck phenomenon: individual cam

For specific methods, see Chapter 4 Valve Clearance

2 Remove the high-pressure oil pipe of the first cylinder of the high-pressure oil pump, and pull the diesel flywheel Liu Gaoyi to purchase the re-flute and then press the diesel engine in the direction of the diesel engine. When the oil is just used, stop [L rotation 6 rounds, and then check the fuel supply advance angle.

Fault 12: The diesel generator set's diesel engine suddenly stops during operation, presses the hand pump, and continues to start, but the diesel engine turns off less than 3m.

Failure analysis:

When the diesel engine suddenly stopped during operation, press the sub-oil pump and continue to start after the system is full of fuel. However, some of the oil cuts do not move for 3 minutes. Suddenly, the sudden suspension of the shed is generally caused by a blockage in the fuel system and low pressure oil entering the air or 51 oil pump failures,

Method of exclusion:

1 When this kind of failure occurs, first of all observe whether the oil pipe joints have oil leakage and tighten the oil return screw.

2 Remove the pump inlet screw (see Figure 5-20) and remove the oil filter well for cleaning.

Other inspections should be conducted.

2 Remove the diesel filter and clean it as shown in Figure 2-63. If the filter element is dirty, replace the new filter element. If the failure of the diesel engine has not been eliminated after the internal filter element of the diesel filter has been cleaned and assembled, the next step should be checked.

4 Remove the oil pump from the top of the high pressure pump and check the wear of the roller which is in contact with the camshaft of the high pressure oil pump. If the roller wears badly or is stuck in the pump body, the above failure will occur.

Fault 13: Diesel generator set diesel engine in normal operation

smoke

Failure analysis:

It was found that the rise in oil level of the engine oil and the large amount of blue-black discharge from the exhaust pipe caused the oil level of the engine oil to increase because the cooling water or diesel leaked into the lubrication system and eventually entered the interior of the oil pan. Determine whether the diesel oil or water is entering the oil pan, and then further analyze and find the fault location.

The specific causes of this fault are: the needle inside the injector is stuck at the maximum position of the fuel supply; the injection pressure of the injector is low; the regulator spring of the injector is broken; there is a crack inside the cylinder head or cylinder liner Causes the cooling water to seep from the crack into the oil pan; the water plug on the cylinder head is damaged or loose; the cooling water enters the oil pan through the oil pan; the cylinder sleeve seals the water ring is damaged; and the cylinder sleeve matches the machine body The copper gaskets at the shoulders are distorted during assembly or the shoulders of the body support are uneven. The height of the cylinder sleeve protruding from the plane of the body is too small: the cylinder head gasket is worn and cracked: the oil radiator core is damaged, resulting in waterways and The oil road communicates.

Method of exclusion:

1After the diesel engine is shut down, an oil scale is drawn to check the quality and quantity of the oil. The purpose of the inspection is to determine whether diesel or cooling water is entering the oil pan through inspection. Take a small amount of oil from the oil pan to observe if the extracted oil is milky white or light yellow foam, after the precipitation, there are drops of water visible from the bottom of the oil, which means that the engine oil enters the cooling water or has a lot of moisture. If the oil color does not change and the viscosity drops, it means that the diesel oil enters the oil.

2 If the amount of diesel oil entering the engine oil is large, the engine oil becomes thin. Then, the oil in the oil pan should be drained. The method is: start the diesel engine to 1000r/min or so, when the standby oil temperature rises to about 50°C, use a special Allen wrench to unscrew the oil drain plug at the bottom of the oil pan (see Figure 5-21) and drain the oil. , and then clean the oil pan with clean diesel oil, then add new oil to the oil pan to the full scale of the oil scale