Hazards of diesel generator valve leakage and matters needing attention during installation and repair

The valve of the diesel generator set is an important part of the unit, which directly affects the sealing and related performance of the unit. Moreover, its working environment is harsh, it will be subjected to strong mechanical load, high temperature and chemical corrosion. It must be installed correctly and the valve is unpacked. During the transportation process, do not bump. During use, do not overload and bear additional additional force. Otherwise, the valve deformation will be invalid, resulting in early damage.

Diesel generator valve leakage will directly affect the operating characteristics of the engine and the economics of use. Therefore, the maintenance and use of diesel generator sets should pay high attention to the valve leakage of diesel generators.

Diesel generator valve leakage can cause engine cylinder leakage, fuel consumption increase, fuel burning in the cylinder, exhaust smoke or air filter helium. In severe cases, the engine will be difficult to start, and even the engine work balance will be damaged. Abnormal vibrations often occur during exercise.

When the diesel generator valve leaks under the high-temperature airflow, the valve head and the valve seat are quickly ablated, causing the mechanical strength to drop, and then wear and deformation, which makes the air leakage more serious and the carbon deposit increases, resulting in a vicious circle.

If the exhaust valve leaks and the exhaust pipe is blocked, the exhaust valve is not smooth, and the valve guide and the conduit gap are too large, a part of the high-temperature exhaust gas will flush the lubricating oil along the gap between the valve guide and the valve guide. After entering the valve chamber, the valve chamber is polluted, the valve arm of the valve chamber is poorly lubricated, the temperature is raised, the carbon deposit is adhered, and the wear and damage of the gas distribution mechanism of the generator set are accelerated.

If the intake valve leaks, the cylinder of the leaking gas is in the process of compression, the compression temperature cannot make the oil injected at the timing spontaneously ignite, and part of the combustible mixture returns to the suction port and the intake pipe through the leakage gap of the intake valve. Then, the intake stroke of the next cycle is re-inhaled into the cylinder. When the constant fuel is injected into the cylinder of the working stroke, the accumulated fuel and the combustible mixture will burn, causing the engine to work rough and emit a knocking sound.

In the case of a multi-cylinder engine, when the intake valves of one or a cylinder leak, the combustible mixture or exhaust gas flowing into the intake pipe will be sucked into the other cylinders, and the operation of the other cylinders will also be affected.

After a gas leakage fault occurs in the diesel generator valve, if the diesel generator is not repaired in time, the valve is re-ground and the sealing is restored. In a short time, it will develop into ablation of the valve seat, the valve head cone and the valve stem root. This can not repair the need to replace new parts and the danger of the valve being broken into the cylinder and the damage of the machine.

Be sure to pay attention to the points when installing and repairing the diesel generator valve.

1. After the new pipe is installed in the cylinder head, the reamer is used to correct the degree of the pipe and the size of the hole, so that the clearance between the valve stem and the pipe hole conforms to the specifications of the diesel generator set, and the finished valve stem cannot be machined. In use, the clearance between the valve stem and the conduit hole shall not exceed the wear limit specified in the unit specification. Generally, as long as the clearance between the valve stem and the conduit reaches 0.13 mm (valve with a diameter equal to or smaller than φ8 mm) or 0.16 mm (rod diameter) Valves larger than φ8 mm require replacement of the valve or conduit, which may result in early damage to the valve.

2. The valves of diesel generator sets of different models in the same series may differ, so do not mix them.

3. For the valve seat of deformation or burn, it must be corrected by the hinge and the grinding. It can not be repaired only by the method of valve-to-valve grinding. For the valve seat that cannot be repaired, it should be replaced with new ones, repaired or newly replaced seat ring and conduit. The hole should be coaxial, the coaxiality tolerance is 0.03 mm, the valve is installed in the valve seat, and the amount of valve and cylinder cover should meet the requirements specified in the unit specification.

4. The valve and the valve seat are gently grounded to ensure the sealing of the valve. The coarse abrasive is not used during grinding. The contact between the valve seat and the valve cone should be in the middle and lower part of the valve cone. The valve and the seat must be sealed and the seal is poor. Will cause the genset power to drop and the valve to be damaged early.

5. After grinding, clean the abrasive with kerosene and lubricate the valve stem and conduit with clean engine oil.