How to Correctly Adjust the Output Power of Diesel Generator Sets

Diesel generator sets are not necessarily constant power when in operation. Some special circumstances will cause diesel generators to overrun. When diesel generators are overloaded, or when the power of the generating units purchased by customers is not good, It is necessary to think about the shadow noise brought about by the overloading operation of diesel generator sets. 

The output power of a diesel generator set is generally 0.9 times the rated power. The standby power refers to the power that the unit can reach but cannot use for a long time. When the diesel generator set is overloaded, the power it needs to provide is greater than 0.9 times the rated power. The unit will stop supplying power in order to maintain itself, and the damage to the generator set will not be great. Therefore, be careful to stop the power supply when the generator set is overloaded. Please decelerate the load in time. If you continue to operate this way, the generator set will be burned out.

For example, if you need a 500KW diesel generator set, then it is recommended that you configure a diesel generator set with a standby power of 600-700KW, because the utilization rate of the unit will be the highest and the unit will be protected in this range. It is also best, but it can't be overloaded. If the unit is overloaded, the unit will be overloaded and the machine will wear quickly, which will greatly reduce the service life of the genset.

What are the diagnostic methods for diesel generators with insufficient power?

This article lists several methods for quickly diagnosing diesel engine output power shortages. Why is the diesel engine power insufficient? The power of diesel engines is the same as other internal combustion engines and is affected by many factors.

1. Look at the charcoal and check the condition

The carbon deposit in the exhaust port of the diesel engine is black and gray, and the surface is covered with a layer of hoarfrost. The carbon deposit is extremely thin, indicating that the diesel engine is in good working condition. The color of the carbon deposit is black and not wet, indicating that the diesel engine burns slightly oil. The deposit of the exhaust port of a certain cylinder is thicker, indicating that the injector of the cylinder is not working properly or the cylinder sealing performance is deteriorated, and repair or replacement should be performed. Individual exhaust ports are wet or organic oil flow marks, indicating that the cylinder oil should be repaired. The carbon deposits in the exhaust ports of each cylinder are thicker and darker in color, mostly due to the working temperature being too low, or the fuel injection is too late, and the post-combustion phenomenon is serious.

2. Look up and down smoke, check the wear

When the diesel engine is working, open the oil port cover, if a thick smoke emerges from the oil port cover, it is said to smoke. The smoke is serious, indicating that the piston, cylinder liner, piston ring and other components are seriously worn. Open the valve cover, such as a trace of blue or white smoke from the root of the valve (valve face), said to smoke. The smoke is serious, indicating that the valve and valve seat are severely worn or ablated, or that the valve clearance is too small or even no gap.

3. Look at the water temperature, check the cooling

If the water temperature of the cooling system is too high (more than 100 °C) when the diesel engine is working, it may indicate that the scale of the cooling water chamber of the diesel engine is too thick or the components of the cooling system (thermoster, water pump, fan, etc.) are inefficient or fail.

4. Look at the gas distribution, check the phase.

After long-term operation of the diesel engine, the timing gear, cam surface, follower column and tappet will wear, so that the opening and closing time of the intake and exhaust valves will be postponed and deviate from the optimal valve timing, so that the charging efficiency is reduced and the diesel engine power is reduced. . Therefore, it is necessary to regularly check the phase of the diesel engine's valve, and if it does not meet the requirements, it should be adjusted in time.

5. Look at the pressure, check the leak.

The cylinder pressure can be measured with a pressure gauge to find a cylinder with poor sealing. The reason for the poor sealing performance of the cylinder is that the valve clearance or clearance is too small, the clearance between the piston and the cylinder sleeve and the piston ring end is too large, and the ring groove is carbon deposited. When the diesel engine is working, if it is close to the air filter, you can hear the sound of “beep, bang”, which means that the air leak is related to the valve. At this point, the cause of the fault can be confirmed by combining the smoke situation.

6. Look at the exhaust, check the smoke.

When the diesel engine is working normally, it usually does not smoke or emit some light grayish white smoke, which is sometimes difficult to see with the naked eye. If black smoke is emitted, it means that there is less oil in the cylinder and the combustion is not complete. If blue smoke is emitted, the wear gap between the cylinder liner and the piston, valve and valve guide is too large; if white smoke is emitted, the fuel is mixed with water, or the diesel is not completely burned, and emerges from the exhaust pipe after vaporization.

7. Check fuel injection pump

The fuel injection pump should not be deflected, oil-free, well-sprayed,and the range is appropriate. When the fuel is sprayed, you can hear the sound of cracking, smashing and feel the pulsation of the high-pressure tubing. Good fuel injection does not fully explain the problem with the oil system. Therefore, it is also necessary to check whether the throttle lever and the joint are stuck or loose.

8. Watch the timing, check early or too late

Seeing the timing means checking the injection timing, that is, whether the fuel supply advance angle is in compliance with the regulations. The fuel supply is too late, the diesel engine is difficult to start, the combustion is not complete, the exhaust smokes, the machine temperature is too high, and the power is insufficient. If the oil supply is too early, the diesel engine will have a knocking sound when working, which will easily damage the parts. It is easy to reverse when starting, and it also affects the diesel engine power.

9. Look at the phenomenon, check the circuit

For electronically controlled diesel engines, the following two conditions will also cause insufficient diesel engine power.

Thermal protection status: If the temperature of the electronically controlled diesel engine is abnormal, the coolant temperature may be too high; the intake air temperature is high; the fuel temperature is too high; the coolant temperature sensor line is faulty (such as open circuit); the intake air temperature sensor line is faulty ( Such as breaking the road);

Failure protection mode: If the electronic control unit of the electronically controlled diesel engine fails, the rail pressure sensor may be damaged or the line is faulty; the fuel metering valve is driven to malfunction, the valve is damaged or the line is faulty.