How to judge fault based on the exhaust gas emitted by Cummins diesel generator

After Cummins diesel generator fuel is burned, the normal exhaust color is generally light gray, and when the load is slightly heavier, it is dark gray. When the Cummins diesel generator is working, abnormal phenomena such as black smoke, white smoke, and blue smoke will occasionally appear. This is the condition for judging the failure of the Cummins diesel generator. Haixing Power will analyze it for you as follows:

(1) Black smoke

Diesel is a complex hydrocarbon. Unburned diesel injected into the combustion chamber is decomposed by high temperature to form carbon black. When exhausting, it is discharged together with the exhaust gas to form black smoke. Black smoke is a sign of incomplete combustion of fuel in the combustion chamber. The main influencing factors are as follows:

1. Wear of piston rings, cylinder liners, etc.

After the piston ring and cylinder liner are worn, the compression pressure is insufficient, causing the normal ratio of the mixture to change at the end of the compression stroke of the cylinder, causing the fuel to burn under anaerobic conditions and producing carbon deposits.

2. The fuel injector is not working properly

The fuel injector does not atomize or drip oil, so that the fuel cannot be fully mixed with the air in the cylinder and cannot be fully burned. The black smoke phenomenon caused by poor fuel injector operation is more obvious when the diesel engine is running at low speed. Because the air intake vortex in the cylinder is weak during low-speed operation, the possibility of oil droplets or oil jets being scattered by the airflow is reduced and the oil droplets stay for a longer time, making it easier to form carbon black discharge.

3. Changes in combustion chamber shape

The manufacturing quality of the shape of the combustion chamber does not meet the technical requirements. If the compression gap is too large or too small and the piston is installed in the wrong position, the shape of the combustion chamber will be changed, thereby affecting the mixing quality of fuel and air, and worsening the fuel combustion conditions.

4. Improper adjustment of fuel supply advance angle

1) The fuel supply advance angle is too large, and fuel is injected into the combustion chamber prematurely. Since the pressure and temperature in the cylinder are low at this time, the fuel cannot ignite and burn. When the piston moves upward, the corresponding pressure and temperature are reached in the cylinder, and the combustible mixture is burned.

2) The fuel supply advance angle is too small, and the fuel injected into the cylinder is too late. Part of the fuel has no time to form a combustible mixture and is separated or discharged. The fuel discharged with the exhaust gas is decomposed by high temperature, forming black smoke.

5. Fuel supply is too large

Excessive oil supply will increase the amount of oil entering the cylinder, resulting in more oil and less gas and incomplete combustion of the fuel. In addition, excessive workload, poor fuel quality, and low operating temperature can also cause black smoke from the exhaust.

(2) Blue smoke

The lubricating oil enters the cylinder and is heated and evaporates into blue oil vapor. Blue smoke is emitted together with the exhaust gas. The main reasons are:

1. The air filter is blocked, the air intake is not smooth or the oil level in the oil basin is too high (oil bath air filter).

2. Mix lubricating oil into the fuel.

3. Match the piston rings.

4. The cylinder gasket near the oil passage from the engine body to the cylinder head is burned out.

5. Piston rings, pistons, and cylinder liners are worn

(3) White smoke

When the Cummins diesel generator is just started or when it is cold, white smoke is emitted from the exhaust pipe. This is caused by the low temperature in the diesel engine cylinder and the evaporation of oil and gas. This is especially true in winter. If the exhaust pipe still emits white smoke when the engine is hot, it is judged that the diesel engine is faulty. The main reasons are as follows:

1. The cylinder liner is cracked or the cylinder gasket is damaged. Cooling water enters the cylinder and forms water mist or water vapor during exhaust.

2. The fuel injector has poor atomization and oil dripping.

3. The fuel supply advance angle is too small.

4. There is water and air in the fuel.

5. The fuel injection pump pressure is too low or the piston, cylinder liner, etc. are severely worn, causing insufficient compression force.

According to different conditions of exhaust gas, we can find and solve problems in time to avoid generators,Generator setThe equipment has suffered greater damage. Haixing hopes that everyone will pay more attention during operation.