Take the multi-cylinder diesel engine as an example, introduce the common failure of the non-demolition inspection method.

1, the diesel engine can not start

The successful start of the diesel engine must ensure that there is a high enough speed, good cylinder compression force, timely spray into the atomized good fuel. In addition, there must be a certain temperature, so that the fuel to reach the ignition state.

Can not start, first check the circuit. Press the start button, start the motor no action, it is the circuit is broken or poor contact. If only the starting gear and flywheel ring gear impact, it is large, small gears can not engage, this time as long as the flywheel plate can be a few teeth. If the starting motor turned weak, low speed, it is the battery power shortage.

If the starting motor is running, the normal speed without fire, nozzle is not called, exhaust pipe smoke, compared to fuel system failure. Or can start, turn a few times and turn off, the fuel has air or moisture.

Start the motor to start the speed, although the nozzle fuel injection call, is not easy to start, and there is leakage of sound. After the stop with a screwdriver to move the flywheel, if the ease, or resistance is very small, flywheel no rebound phenomenon, then the lack of compression.

If the ambient temperature is too low, or the machine to stop for too long, the oil is too thick, moving parts resistance, piston and cylinder clearance is too large, lack of compression force, are difficult to start. At this point the application of hot water or steam preheating machine and then start.

2, diesel engine power shortage

The main feature is the low speed operation is not smooth, high-speed exhaust pipe black smoke, abnormal sound. Diesel engine in the case of failure to reach the overhaul period, the power shortage is mainly fuel supply system failure and cylinder compression due to lack of.

First empty car inspection, if you increase the throttle, empty car can reach the maximum speed, the fault in the work of machinery. If the empty speed does not go, then the fault in the diesel engine.

Check the northbound v3 accessories exhaust manifold root temperature, if a cylinder temperature is low, the cylinder does not work or work poorly. Low speed can be used for finger touch check, high speed is not to prevent burn your fingers. At this point to the exhaust manifold spit saliva, if the saliva did not issue a “bared” sound, the cylinder is faulty.

With a finger pinch the North Ben v3 accessories high-pressure tubing, if the pulse is strong, and the temperature higher than the other tank, said the pump is good, and the nozzle may be in the fully closed position or nozzle pressure spring pressure is too large; if the high pressure tubing pulsation Faint, temperature consistent with other cylinders, indicating that the nozzle in the fully open position to kill or pressure spring break. If the high-pressure tubing at high speed without pulsation, the temperature is higher than the other cylinder, said high-pressure pump failure. If the exhaust pipe at low speed spit, said the high-pressure oil pump valve spring break or gasket failure. If the fuel system has no abnormal symptoms, the fault is poor cylinder compression.

In operation, if the machine under the mouth of the channeling gas increased, the smell of heavy oil, it is the piston and cylinder clearance is too large, poor sealing. If you use the screwdriver to move the flywheel for two weeks, feel the number of resistance increases and the number of cylinders, you can determine a poor compression according to feel. If the cylinder head and the cylinder at the junction of the leak sound, the environment is strong smoke, smoke paste taste, said the cylinder pad leak. If the cylinder shell with a metal percussion sound, and with the speed is related to a regular, then the rocker and valve clearance is too large. If the cylinder head at the leak sound, low speed, the intake manifold root temperature is high, parking in the intake pipe at the air leakage, then the air intake valve; if the high-speed exhaust pipe black smoke, night Exhaust pipe spit tongue, then the exhaust valve leak.

3, automatic flameout

Automatic flameout for a variety of reasons, but mainly two aspects, one is the fuel supply interruption; the second is blocked by moving parts.

In the normal operation of the process, if the speed gradually slow down, the sound gradually weakened, the water temperature, oil temperature, pressure are normal, to promote the throttle no effect, after a period of time gradually turn off, after the use of screwdriver can hold the flywheel, Fuel supply is poor or interrupted.

In the course of the operation, the oil pressure is normal, but the oil temperature is high, the water temperature is increased, and there is paint taste, the cooling water outlet water is small or no water, steaming straight, the machine is running hard, loud, Sound, the speed gradually reduced, the last stop, the flywheel is reversing difficulties, stop the disk after the flywheel. After the machine temperature is reduced, but also the flywheel, it can be judged that the piston killed.

During the operation, the water temperature is normal, the oil pressure drops, the oil temperature rises, the oil has metal debris, the smell of organic oil burning, the machine vibration intensifies, the sound is abnormal, the speed gradually decreases, the inertia rotation time is short, After the disk does not move the flywheel, the machine is still fixed after the flywheel, you can determine the spindle burner, also known as the axle.

4, oil sump oil surface increased

Oil surface increased, indicating that oil leakage into the cooling water. It is mainly caused by the North Ben v3 accessories cylinder head, cylinder liner, cylinder block and cylinder seal, oil cooler seal caused by failure.

Check, the hand can be aligned with the oil port of the hot air, if the hand has condensation, then there is cooling water within the oil. When the low speed or parking oil without pressure, but also that there is cooling water within the oil.

If the oil sump oil surface rise, start difficult, the formation of water, exhaust pipe at low speed when the white smoke, then the cylinder head crack, cooling water into the cylinder. If the oil level is significant, start normal, low-speed exhaust pipe does not take white smoke, it shows that the cylinder crack or cylinder rubber seal failure, cooling water directly into the oil pan.

5, oil consumption increased

Increase in oil consumption is mainly due to oil into the cylinder combustion, the cylinder junction at the oil spill, crankshaft oil seal failure caused.

Low-speed exhaust pipe to take the blue smoke, it is the oil into the cylinder combustion, mainly the piston and cylinder clearance is too large, or the piston ring caused by the counterparts. If this happens after the repair, it is caused by oil ring chamfering. If the joints of the screw loosening, sealing ring damage will cause leakage.

If the rotating flywheel throws oil droplets, it indicates that the spindle seal has been damaged.

6, oil pressure drop or no pressure

Cause oil pump damage, oil blockage or leakage, pressure spring break, pressure gauge failure and so on.

In the course of operation, if the pressure gauge pointer is always stopped at a lower pressure position, do not change the position after stopping, it is pressure gauge failure.

Just start, the oil pump pressure gauge pointer does not move, oil sump no change in the liquid level, and can not hear the fine filter rotor running sound, then the oil pump failure.

Oil pressure is low and unstable, the pressure was gradually downward trend, said the oil circuit leakage. This is because the strength of the gasket in the weak place in the role of pressure under the first small gap, the gap gradually expanded, so that the oil flow short-circuit back to the oil pan.

In the course of operation, with the screwdriver to adjust the oil pressure screw, if the pressure does not change, then the pressure spring break failure.

7, oil fine filter plug

Oil fine filter rotor in the two nozzles under the reaction of high speed, after stopping under the action of inertia can continue to run for about 1min, otherwise, that the rotor has been blocked.

8, piston pin and connecting rod bushing gap is too large

Low-speed operation, the upper part of the cylinder issued a crisp percussion sound, sound increased with the increase in load. At high speed, the sound disappears. Sound has nothing to do with the oil pressure, oil pressure gauge pointer no change. After stopping with a screwdriver toggle the flywheel two teeth, so that the piston for reciprocating motion, if the impact of feeling, then the piston pin and connecting rod gap is too large.

9, connecting rod bearing gap is too large or broken

Low speed when the load on the lower part of the cylinder in the impact of the sound, the pressure table pointer swing frequency and the same sound frequency, the sound changes with the speed at the same time, the sound is greater than the sound of the machine burst. After stopping with a screwdriver toggle the flywheel two teeth, the sound is clear, there is a sense of impact that the rod bearing gap is too large or broken.

10, crankshaft fracture

In the course of the operation, suddenly issued a strong crack crash, oil pressure plummeted, and then automatically flameout. With both hands to grasp the crankshaft front wheel for reciprocating push and pull, if the crankshaft has a larger axial movement, and the flywheel failed to move with the crankshaft, then the crankshaft fracture.