Fuel scours at higher pressure and speed, which is the main cause of wear of needle valve shaft and valve body nozzle. At the same time, the nozzle part of the shaft needle extends into the combustion chamber to contact the combustion gas, making the surface brittle, resulting in peeling or comb-shaped groove marks.. When the belt is widened, the fuel will leak and drip from the seat surface, causing coke deposits, difficult starting, black smoke, power drop, and fuel consumption increase. In this regard, the pressure regulating spring should be updated. The positive ring shape causes the fuel injection pressure to drop, the spray quality deteriorates and the fuel injection time shortens, and it should be replaced and repaired.004mm.

 

Causes the surface to stick to wear and get stuck.2-0. If there is no new pressure regulating spring to replace, a small washer of appropriate thickness can be added between the original pressure regulating spring and the pressure regulating spring seat to increase the preload of the spring. The fuel injection pump draws high-pressure fuel from the fuel injector inlet pipe joint through the fuel injection The oil passages in the body and the needle valve body enter the annular high-pressure oil chamber in the middle of the needle valve body.

 

Common faults and maintenance methods of fuel injectors The working conditions of the fuel injector are very harsh, the mechanical load and thermal load are high, and the installation and adjustment are not proper, often there will be failures such as poor spraying, dripping of the nozzle, carbon deposit, and even the needle valve stuck. The elastic force of the pressure regulating spring is insufficient. If there is air, remove it in time; whether the fuel supply of the fuel pump is normal; whether the fuel system is leaking; whether the fuel injection needle valve is stuck in the needle valve hole, if necessary, disassemble, clean and repair it. The sealing cone at the lower part of the needle valve is pressed against the sealing cone of the needle valve body and the nozzle hole is closed, and the fuel injection stops. The oil pressure acts on the pressure-bearing slope in the middle of the needle valve to form an upward axial thrust.

 

The fuel injector is composed of a fuel injector body, a tappet, a fuel injector coupling piece, a pressure regulating spring and other parts. Check whether there is air in the oil circuit. If the surfaces of the two parts are invaded by dust and mechanical impurities, the geometric accuracy and roughness of the guide surface will be destroyed, and the contact surface will generate high pressure and instantaneous high temperature. The matching clearance of the needle valve body is very small, only about . The fuel injector does not inject fuel. If the fuel entering the fuel injector contains particulate mechanical impurities, groove marks will be ground on the surface of the The best foundry cone. The injection pressure of the injector is too low, and the fuel atomization is poor and cannot be adjusted. The shaft needle head changes from the original cylindrical shape to the conical shape, and the nozzle hole diameter is also worn and lost.

 

Axle needle and nozzle are worn out.3mma. The sealing cone is worn. Generally, the cone angle of the valve body is 590, while the needle valve cone angle is 600, and the contact surface width is 0. When the fuel supply is interrupted and the oil flow pressure drops, the needle valve quickly returns to its position under the action of the pressure regulating spring. The problem of insufficient elasticity. In this case, new parts should be replaced. The compressed gas in the cylinder pushes the injector needle valve and passes through the oil return pipe to the high-pressure fuel pump, causing the diesel engine to stall without pumping oil.

 

When this thrust exceeds the pressure regulating spring When pressure is applied, the needle valve moves upward, and the fuel passes through the four nozzle holes at the bottom of the valve body and sprays into the combustion chamber in an atomized state. ③The guide surface of the needle valve is worn.002 to 0. It should be cleaned and maintained frequently, and replaced when necessary

Megosztás a facebookon