Fault analysis of diesel generator set
I. some cases of diesel generator, diesel generator can not be started
There are many reasons why the diesel engine can't be started, including the following four points: 1. Starting system. 2. Fuel system. 3. Insufficient compression stroke pressure. 4. Impact of ambient temperature
1. Startup system
(1) the starting battery voltage is low, and the actual capacity is insufficient;
(2) wrong wiring between starting battery cable and motor;
Fault of electromagnetic switch of starting motor;
(4) the starting contactor of Cummins diesel engine fails;
Use a multimeter to measure whether the voltage of single battery and DC output of charger are normal, check the liquid level of lead-acid battery, and add distilled water in time;
Dismantle the motor, check and adjust the internal contact of the electromagnetic switch. If the contact burns out, replace the electromagnetic switch;
Check whether the negative cable of the battery is grounded (enclosure), if the wiring is wrong, reconnect the cable;
Use a multimeter to measure the coil resistance of the starting contactor of Cummins, kalerbit and tengdao diesel engines (the resistance value is generally dozens of ohms), and replace the contactor if it is abnormal;
Tengdao diesel generator set
2. Fuel system
Air leak in fuel system
Low pressure oil pipe air exhaust method: loosen the vent plug on the fuel injection pump, press the hand pump of the fuel delivery pump until the diesel overflows without bubbles, then tighten the plug and tighten the hand pump. High pressure oil pipe air exhaust method: loosen the high pressure oil pipe joint of the injection pump one by one, start the diesel engine until the oil is discharged from each cylinder, and then tighten the high pressure oil pipe joint. The difference between Cummins diesel engine and other diesel engines is that it depends on starting the diesel engine.
Open frame diesel generator
3. Insufficient compression stroke pressure
Air leakage of valve;
The piston ring is excessively worn.
Dismantle the cylinder cover and cylinder head, check the valve clearance, valve spring, valve guide and valve seat sealing. If the valve sealing line is not continuous, grind it to a continuous and smooth line with valve grinding sand;
Take out the piston and replace the piston ring.
Tengdao diesel generator
4. Impact of low ambient temperature
The diesel oil is too thick.
Remove the heater side cover, check whether the AC input terminal wiring and voltage are normal. If it is normal, the heater is broken, replace the heater;
(2) add kerosene to diesel oil in proportion, or choose No. 10, No. 20 and No. 35 (the number indicates the freezing point temperature, and the freezing point of No. 10 light diesel oil is - 10 ℃) light diesel oil.
Case 2: the exhaust smoke color of diesel engine is abnormal
When the diesel engine operates normally with load, the exhaust smoke color is generally light gray, and when the load is slightly heavy, it may be dark gray. The abnormal exhaust smoke color here refers to:
1. Black smoke from exhaust;
2. White smoke from exhaust;
3. Blue smoke from exhaust.
1. Black smoke from exhaust
(1) overload operation of diesel engine;
(2) the injector drips oil and has poor atomization;
The oil supply time is too early.
Adjust the load to be within the rated range;
(2) when the diesel engine is idling, loosen the high-pressure oil pipe joints of the fuel injectors one by one to stop the fuel injection of the fuel injectors, and observe the color of the exhaust gas: when there is no fault of the fuel injectors, the speed of the diesel engine will drop significantly after stopping the fuel injection. When there is a fault in the fuel injector, the speed of the diesel engine changes little after the fuel injection is stopped, and the exhaust does not emit black smoke. Check and adjust the fuel injector;
Check and adjust the oil supply advance angle according to the instructions.
The fuel injector has the following requirements: a certain injection pressure, a certain range, a certain spray cone angle, and a good spray. The oil can be stopped quickly after oil injection, without oil leakage and oil leakage.
2. Failure analysis of white smoke from exhaust
The cylinder gasket is damaged;
(2) oil supply time is too late;
There is water in diesel oil. Fault handling
Replace the cylinder gasket;
Check and adjust the oil supply advance angle according to the requirements of the manual;
(3) install the fuel water separator.
In order to make the cylinder sealed well, a cylinder gasket must be added between the cylinder head and the cylinder block. The cylinder head is fastened on the cylinder block with bolts, and the bolts shall be tightened in a certain order, that is, they shall be expanded from the center symmetrically to the four sides in several times, and the last torque wrench shall be tightened according to the torque value specified in the instructions. Remove the bolt and vice versa.
3. Blue smoke from exhaust
The oil level of oil pan is too high;
(2) the oil ring is stuck in the ring groove or broken;
The clearance between connecting rod bearing bush and connecting rod journal is too large.
(1) keep the oil pan oil at the full scale of the scale, and drain some oil timely;
Clean the carbon deposit in the piston ring groove and replace the oil ring;
Remove the oil pan and connecting rod bolts and take out the bearing bush. Check whether the surface of the bearing bush is burned. If yes, replace the connecting rod bearing bush.
Case 3 low oil pressure of diesel engine
(1) the oil level in the oil pan is low;
(2) the spring of oil pressure regulator is broken;
Aging and oil leakage of rubber gasket of oil filter (generally domestic diesel engine);
The oil pressure gauge is broken;
The oil filter in the oil pan is blocked.
(1) keep the oil pan oil at the full scale of the scale, and add oil timely;
Replace the oil pressure regulator spring;
Replace the rubber band pad;
Replace the pressure gauge;
Remove the oil pan and clean the oil filter.
Oil pressure adjustment method: screw off the oil seal nut on the regulating valve and loosen the lock nut