New Fuel Injector Nozzle Dsla143p1535 0433175456 OE 2854608 504091505 for Fuel Injector 0445120057

1. Fuel temperature field in the gap between the needle valve coupling parts:

When the needle valve reciprocates, the kinetic energy lost by the shear flow friction between the needle valve couple and the gap fuel is converted into heat energy, and the gap

The temperature of the oil film rises gradually, and the fuel will expand when the temperature rises, so that there is an additional pressure on the oil film in the gap

field, the load capacity of the oil film increases, this phenomenon is the thermal wedge effect. When the shear flow is not considered, the fuel flow rate is reduced due to the wall viscous resistance. When the needle valve is stationary or moving at a low speed, the pressure loss of the fuel is all converted into heat energy. In a short time, heat is difficult to transfer to the solid wall, so it is simplified as an adiabatic process.

2. Leakage in the ring gap of the needle valve coupler:

The needle valve coupling is sealed by the oil film in the gap, and the thickness of the oil film is about 2 μm. This kind of micron ring gap is widely used in high-pressure and high-speed sealing. Strong shear composite flow.The gap size of the needle valve couple is very small. It relies on diesel to achieve self-lubrication. When it flows in the micron-level gap, the viscosity of diesel oil is large, and the Reynolds number is small. can be seen as layers.

3. Radial deformation of the needle valve coupling:

As the pressure of the fuel supply system increases, the oil storage groove and the sliding surface clearance of the needle valve assembly are subject to a large load. It causes the elastic deformation of the needle valve coupling, changes the radial film thickness distribution of the oil film in the gap between the needle valve coupling, and thus affects the sealing characteristics of the needle valve coupling.