1. Diesel engine cannot start
Successful starting of the diesel engine must ensure sufficiently high rpm, good cylinder compression and rapid injection of well-atomized fuel. In addition, there must be a certain temperature to allow the atomized fuel to reach an ignition state.
When it cannot start, check the circuit first. If the starter does not move when you press the start button, the circuit is open or the contact is bad. If there is only an impact sound between the starter gear and the flywheel ring gear, it means that the large and small gears are not meshing. At this point, simply move the flywheel one to a few teeth. If the starter motor weakens and the speed is low, the battery power is insufficient.
If the starter works powerfully, turns normally but does not ignite, if the oil jet does not scream and if the texhaust pipe does not produce smoke, this is a fuel system fault. Or, although it can start, it goes out after a few revolutions, then there is air or moisture in the fuel.
When the starter reaches the starting speed, although there is fuel injection sound from the fuel injector, it is not easy to start and there is a air leak noise. After stopping the machine, use a screwdriver to turn the flywheel. If it is easy and weak, or the resistance is very small and the flywheel has no rebound, it means that the compression force is insufficient.
If the ambient temperature is too low or if the machine has been stopped for too long, the engine oil is too thick, the resistance of the moving parts is high, the gap between the piston and the cylinder is too large, the compression force is insufficient, etc., itIt's hard to get started. At this point, use hot water or steam to preheat the machine before starting it.
2. Insufficient diesel engine power
The main characteristics are unstable operation at low speed, black smoke from the exhaust at high speed, and abnormal noise. When the diesel engine has not reached the overhaul period, the lack of power is mainly caused by fuel system failure and insufficient cylinder compression.
Check first when the engine is empty. If the engine can reach maximum speed when the engine is empty by increasing the throttle, the fault lies with the operating machine. If the idle speed cannot increase, the fault lies with the diesel engine.
Check the temperature at the root of the exhaust manifold. If the temperature of a certain cylinder is low, the cylinder will not fodoes not work or malfunctions. You can use your fingers for touch inspection at low speed, but not at high speed to avoid burning your fingers. At this time, you may spit saliva at the root of the exhaust manifold. If the saliva does not make a “squeaking” sound, the cylinder is defective.
Pinch the high pressure oil pipe with your fingers. If the pulsation is strong and the temperature is higher than the other cylinders, this means that the oil pump is in good condition and the fuel injector may be stuck in the fully closed position or pressure from the fuel injector pressure regulating spring is too high; if the high pressure oil pipe has low pulsation and the temperature is consistent with that of the other cylinders, which means the fuel injector is stuck in the fully open position. position where the pressure regulating spring is cass. If there is no pulsation in the high-speed high-pressure oil pipe and the temperature is higher than that of other cylinders, it means that the high-pressure oil pump is defective. If the exhaust pipe is spewing smoke rings at low speed, it means that the high pressure oil pump discharge valve spring is broken or the seal is failing. If there are no abnormal symptoms in the fuel system, the problem is poor cylinder compression.
During operation, if the air blown under the oil filling port increases and the ambient oil smell is strong, the gap between the piston and the cylinder is too large and the sealing is poor. If you use a screwdriver to turn the steering wheel for two weeks when parking, and the number of increases in hand resistance varies depending on the number of cylinders, you can judge that a cSome cylinder has poor compression depending on hand feel. If there is a sound of air leaking from the gasket between the cylinder head and the cylinder block and the environment is rich in smoke and smoke odors, it means that the cylinder gasket is leaking. If there is a metallic knocking sound on the cylinder cover, and it is related and regular to the rotation speed, it means that the gap between the rocker arm and the valve is too large. If there is an air leak noise at the cylinder head, the temperature at the root of the intake manifold is high at low speeds and there is an air leak noise at the intake pipe. intake when parked, it means the intake valve is leaking if; black smoke is emitted from the exhaust pipe at high speed, it means the engine is leaking at night. If the exhaust pipe is spewing flames, it means the exhaust valve is leaking.
3. Extinction attomatic
There are many reasons for automatic shutdown, but there are mainly two aspects: the fuel supply is interrupted; the other is that the moving parts are interrupted. blocked.
During normal operation, if the speed gradually slows down, the explosion sound gradually weakens, the water temperature, oil temperature and pressure are all normal, and pressing the accelerator has no effect and the engine runs gradually. turns off after a while, use a screwdriver after parking the car. If the steering wheel turns, this indicates poor or interrupted fuel supply.
During operation, the oil pressure is normal, but the oil temperature is high, the water temperature is increased, and there is a paint smell. There is little or no water coming out of the cooling water outlet. , steam comes out, the machineurn loud and the noise is rough, when approaching the stop, there is a cylinder pulling noise and the speed gradually decreases when the car finally stops, it is difficult for the flywheel to turn . forward and backward, and the disc does not move the steering wheel after stopping. Once the machine temperature has dropped, the steering wheel can turn again. On this basis, it can be judged that the piston is seized.
During operation, the water temperature is normal, the oil pressure drops, the oil temperature rises, there are metal shavings in the oil, the smell of If the oil is burned, the vibration of the machine increases, the sound is abnormal, the speed gradually decreases, and the machine is stopped. When the inertial rotation time is short, the steering wheel does not move after parking, and the steering wheel still does not move after the machine cools down, it can be judged that the spindle is burning, also known astree hold noun.
4. The oil level in the oil pan rises.
The oil level rises, indicating that cooling water has seeped into the oil. This is mainly due to cracks in the cylinder head, cylinder liner, cylinder block and failure of the cylinder liner seal ring and oil cooler seal ring.
When checking, you can point your hand towards the hot air coming out of the oil filler port. If there is condensation on your hand, it means there is cooling water in the oil. When there is no engine oil pressure at low speeds or after stopping, this also indicates that there is cooling water in the engine oil.
If the oil level in the oil pan rises, starting is difficult, a water surface forms, and white smoke comes out of the exhaust at low revs, thisindicates that the cylinder head is cracked and cooling water has entered the cylinder. If the oil level rises significantly, starts normally, and does not emit white smoke from the exhaust at low speeds, this indicates that the cylinder block has cracks or the cylinder liner rubber seal is damaged. defective and cooling water enters directly into the oil pan. .
5. Increased oil consumption
Increased oil consumption is mainly caused by oil entering the cylinder for combustion, oil leakage at the block gasket cylinders and crankshaft oil seal failure.
When blue smoke comes from the exhaust at low speed, it means that engine oil is entering the cylinder and burning. This is mainly due to too large a gap between the piston and the cylinder. piston rings rotating in the opposite direction.If this phenomenon occurs after maintenance, it is due to the fact that the oil ring chamfer is installed backwards. If the screws in each joint are loose and the gasket is damaged, a leak will also occur.
If the rotating flywheel sprays oil droplets, it means that the main shaft oil seal is damaged.
6. Oil pressure drops or there is no pressure
The reasons include damage to the oil pump, blockage or leakage of the oil circuit, breakage of the regulating spring pressure, pressure gauge failure, etc.
During operation, if the pressure gauge needle always stops at a lower pressure position and does not change position after stopping, the pressure gauge has a malfunction.
At the beginning of starting, if the oil pump pressure gauge needle does not move, the fluid level in the oil pan does not dropand the noise of the fine filter rotor cannot be heard, it indicates that the oil pump is defective.
The oil line pressure is low and unstable, and the pressure gradually decreases, indicating a leak in the oil line. This is because the weak areas of the seal first present a small gap under the action of the oil under pressure, then the gap gradually expands, causing a short circuit and a reflux of the lubricating oil towards the crankcase of oil.
During operation, use a screwdriver to adjust the oil pressure regulating screw. If the pressure does not change, the pressure regulating spring is broken and failing.
7. The fine oil filter is clogged.
The rotor of the fine oil filter rotates at high speed under the reaction of the two nozzles. It can continue to work for about 1 minute. the action of inertia after stopping. Otherwise, it means that the rotor is cloggede.
8. The gap between the piston pin and the connecting rod bushing is too large.
When operating at low speed, the middle and upper part of the cylinder emits a sharp knocking noise, which intensifies as the load increases. At high speeds, the sound disappears. The noise has nothing to do with engine oil pressure and the oil pressure gauge needle does not change. After parking, use a screwdriver to move one or two teeth of the steering wheel to move the piston. If there is a feeling of impact, it indicates that the gap between the piston pin and the connecting rod bushing is too large.
9. The connecting rod bearing clearance is too large or broken.
When the load is applied at low speed, there is an impact sound in the lower part of the cylinder. The oscillation frequency of the oil pressure gauge pointer is consistent with the sound frequency. The sound changes simultaneously with the rotation speed and the sound is supprior to the explosion of the machine. After parking, use a screwdriver to move one or two teeth of the steering wheel back and forth. If there is a clear sound and a feeling of impact, it indicates that the connecting rod bearing clearance is too large or broken.
10. The crankshaft is broken
During operation, a loud cracking impact sound is suddenly heard, the oil pressure drops sharply, and the engine automatically stalls. Use both hands to grip the front crankshaft pulley and push and pull it back and forth. If the crankshaft has significant axial movement and the flywheel fails to move synchronously with the crankshaft, this indicates that the crankshaft is broken.
Generator short circuit.
Generators (generators) refer to mechanical equipment that converts other forms of energy into electrical energy. He is trainedby a water turbine, steam turbine, diesel engine or other electrical machines and burns water. flow, air flow and fuel. Or the energy generated by nuclear fission is converted into mechanical energy and transmitted to the generator, which is then converted into electrical energy.
The stator and rotor of the generator are connected and assembled by the bearings and end covers, so that the rotor can rotate in the stator and carry out the cutting movement of the magnetic lines of force, thus generating an induced effect. electric potential, which is discharged through the terminals and connected to the circuit, an electric current is generated.
Generators are widely used in industrial and agricultural production, national defense, science and technology and daily life. There are many forms of generators, but their operating principles are all based on the law of electro inductionmagnetic and the law of electromagnetic force. Therefore, the general principle of its construction is: using suitable magnetic and electrically conductive materials to form magnetic circuits and electric circuits that perform electromagnetic induction on each other.path to generate electromagnetic energy and achieve the energy conversion target.