Diesel generator set maintenance training diesel engine -p136-p140 diesel engine...

Diesel generator set maintenance training diesel article -p136-p140 diesel engine troubleshooting examples

Section II Diesel Engine Diesel Engine Fault Repair Example

One, 2135 diesel engine troubleshooting examples

Therefore, it was revealed that 1: Diesel generator set diesel engine starts, the vibration and noise is larger, the exhaust gas exhausts, and the black smoke is analyzed.

After the diesel engine is started, it can reach the rated speed and can generate power normally when there is no load. However, when the load is added, it fails to reach the rated speed. The vibration and sound are loud and the exhaust pipe emits black smoke. Hei-Yuan is due to incomplete combustion of diesel fuel injected into the combustion chamber. The causes of such failure phenomena in diesel engines are: overload; uneven supply of oil from the plunger in the high-pressure pump; poor or poor fuel injection in the injector; serious air leakage in the single-cylinder or double-cylinder combustion chamber; The cleaner is partially blocked.

Method of exclusion

1 Check the power consumption of the load and the output power of the diesel engine is 20kw.

2 After starting the diesel engine, increase the speed to about 900r/mh, and then use an open-end wrench to disconnect the high-pressure fuel pipe of the first cylinder or the second cylinder, as shown in Figure 5-5. If the first cylinder high pressure fuel line is disconnected, the diesel engine slowly stops rotating, which means that the second cylinder does not work.

3 Remove the injector of the second cylinder, and then perform a technical inspection. As a result, it is found that the nozzle hole has been rusted so that the high-pressure fuel cannot be ejected. It is further determined that the diesel engine is overloaded after starting, and the original two Cylinder work becomes a cylinder work, from the original two cylinders responsible for the 15kw consumption of power string into a married cylinder responsible for 15kw of power consumption, resulting in the first cylinder of diesel injection too much, the air coefficient decreases, so that the combustion chamber The diesel fuel does not get enough fresh air to fully burn, causing the exhaust pipe to emit black smoke and the power to drop.

4 Replace the fuel injector and perform fuel pressure correction (see Figure 2-81). Then assemble the fuel injector and start the diesel engine to the rated speed. Find that the exhaust pipe is black smoke disappears and the work is stable, and the power is also higher. Improvement, the above failures have been ruled out.

Fault 2: After the diesel engine stops rotating, it flows out of the heater discharge valve when the oil radiator is drained. Further inspections have found that the inflow failure has been analyzed in the oil pan:

In order to make quick judgments on such failures of diesel generators, it is first necessary to understand whether the oil cooling method of this firewood is air-cooled or water-cooled. If it is a water-cooled method, also observe whether the water-cooled oil radiator is placed inside or outside the oil pan. The oil radiator of the Model 2135 diesel engine is exposed to the oil in the oil pan, and the internal core of the radiator is bound to cause the oil and cement to merge. This is because when the diesel engine is in operation, the pressure of the cooling water is higher than the oil pressure, so that the cooling water is pumped into the oil pan through the damaged part of the oil radiator core and mixed with the oil; when the diesel engine stops rotating and the cooling water is After the radiator is drained clean, the oil in the oil pan is higher than the radiator, so the oil enters the oil radiator through the damaged part of the core.

Therefore, when the operator puts water into the oil radiator, it will find a small amount of oil flowing out of the radiator. Caused by the above-mentioned failure is due to the cracks between the water channel inside the cylinder head and the oil passage, and the cylinder gasket is damaged to make the passage connect with the water passage.

Method of exclusion:

1 Drain the oil in the oil pan and the cooling water remaining in the oil radiator.

2 Remove the mooring bottom shell and further inspect the oil radiator. As a result, it is found that the oil radiator tube has a convex portion on one side and a crack in the middle of the convex portion (see Figure 5-6). This is the fault. The occurrence of this situation is mainly due to the operator's demand for net cooling water in winter.

Figure 5-6 cracks of oil cooling 5Sg-W

2 Gas welding can be used to repair damaged parts of oil radiators or replace new radiators. The precautions when using 2135K-1 diesel engine in cold areas are as follows; 1 When the diesel engine is working, the body requirements are stable, so that the internal of the oil radiator can be Cooling water is released.

2 After the body has been drained, start the diesel engine at about 2mln and drain the cooling water remaining inside the body.

Therefore, Hitomi 3; when the diesel engine was overhauled and operated at rated speed, the connecting rod bolts were broken, and the connecting rods took the big head to break the failure analysis of the machine body.

Diesel generator set diesel engine after overhaul operation at rated speed, the occurrence of failure of the connecting rod bolt to break the body of the connecting rod (see Figure 5-7), generally because the maintenance staff in the assembly rod Luo Gui excessive force Exceeding the yield limit of the bolt material causes slight deformation of the bolt, which results in a reduction in the tightness of the bolt, and breakage of the connecting rod bolt due to excessive waste elongation after the diesel engine starts to impact. On the contrary, if the tightening moment of the bolt is too small, a gap will be formed at the joint of the two bearing caps, which also causes the connecting rod bolts to be fractured due to a large impact load. Specific analysis is as follows:

1 The force is not uniform when assembling the connecting rod bolts. The correct method is to use a torque wrench and use even force. The connecting rod bolt tightening torque of 135 series diesel engine is 255~274N·m. For connecting bolts that are not lock bolts, a torque of 177 to 196 N·m can be used, but they must be fixed with steel wire or phosphor bronze wire.

The connecting surface of the two connecting rods is not tightly fitted. When the diesel engine is running, the upper and lower covers of the connecting rod are loosened and the bolts are broken.

2 The connecting rod bearings of this diesel engine are newly assembled, and the surface of the bearing pads may be caused by poor fitting and “holding the tiles”.

Phenomenon, resulting in breakage of the connecting rod and bolt to break the body.

4 蛹 蛹 蛹 蛹 蛹 贴 贴 贴 螺母 螺母 螺母 螺母 螺母 螺母 螺母

Cause additional bending stress.

6 The material of the connecting rod bolt is defective.

Method of exclusion:

Unclean and skewed during assembly

According to the technical requirements for assembly, and the use of qualified rod bolts.

Fault 4: It is difficult to start the diesel engine after overhaul

Failure analysis:

When the diesel generator set diesel engine starts, the crankshaft will not turn or rotate slowly when it is rotating, which will make the diesel engine unable to start. This kind of failure is generally due to the starting resistance of the diesel engine is too large or the starting torque is too small, the specific causes of the failure are:

Incorrect adjustment of valve clearance; insufficient battery power; premature starter itself or bad contact between carbon brush and copper shaft; poor contact between electromagnetic switch contact and contact copper plate: poor contact of starter commutator: when maintenance personnel assemble the connecting rod bolt If the force is too great, the gap between the bearing bush and the uranium neck is too small, which causes the friction resistance of the diesel engine to increase at the start.

Method of exclusion.

1 As shown in Figure 2-35, use a flat-blade screwdriver to pull the diesel flywheel to feel that the rotation resistance is normal. If you feel that the rotation resistance is large, it means that the fault may be caused by the improper torque of the diesel engine assembly or incorrect adjustment of the valve clearance.

2 Remove the cover plate on the side of the fuselage, and then use the torque wrench village connecting rod to carry out the inspection. During the disassembly process, it is found that the disassembly torque is 314 N·m. This shows that when the connecting rod Luogui is used with too much force, there is no 274N according to the provisions of the diesel engine. · m Momentary assembly. After assembling the connecting rod bolts according to the specified torque, the diesel engine is started and the above-mentioned failure is eliminated.

Note: When the engine flywheel is pulled, if it feels that the rotation resistance is slightly larger than that before the overhaul, it is normal; if the diesel engine is difficult to start, then the failure may be caused by the starter running ineffective or the starting torque is too small, which can be replaced by A fully-charged battery or a method of replacing the same type of starter starts the diesel engine.