The normal oil working pressure of the diesel engine pump set should be between 0.25-0.35 MPa, which can be higher when the new machine or machine temperature is low, and lower when the old machine or machine temperature is high. When the machine is working, if the oil pressure is lower than 0.2MPa or it changes with the speed, it will suddenly drop to zero, indicating that there is a problem in the machine. It should be turned off immediately to find the cause, and the fault can be restarted. Otherwise, it will lead to a big accident of burning the cylinder. Among them, the insufficient oil output of the KDCB diesel engine gear pump is one of the reasons.
KDCB diesel engine gear oil pump has two kinds of the gear pump and rotor pump. Some gear pumps have a low roughness between the pump cover and the pump body. The original design does not have a gasket. If the paper pad is added during the inspection, the end face clearance of the gear is increased, which will reduce the oil output of the pump. However, there is a gasket at the joint surface of the pump and the cylinder. If it is leaked, the hydraulic oil from the KDCB diesel gear pump will leak outward, causing the oil pressure to drop. Some rotor pumps have a chamfer on one side of the outer rotor and no chamfer on the other side. If installed, the oil output can be reduced by 40% to 60%. In addition, when the radial and end gaps of the gear or the rotor are excessively worn due to wear, the pump’s oil output is reduced and the oil pressure is lowered.
The repaired KDCB diesel engine gear oil pump should be adjusted on the test bench to adjust the opening pressure of the pressure limiting valve to keep it between 0.5-0.7MPa. If the pressure is too high, it will accelerate wear; if the pressure is too low, it will cause the main oil passage pressure to drop. When installing the KDCB diesel engine gear oil pump, it should be filled with oil first, so as to avoid the air in the pump and the oil cannot be sucked. The connection between the KDCB diesel gear oil pump and the oil suction pan must be sealed. If the air leaks, the oil output of the oil pump will also be reduced.
Check if the oil suction net is blocked, the gear and the end face of the casing are worn, and the bypass valve is normal. If the KDCB diesel gear oil pump bypass valve spring becomes soft, it will cause the oil to leak before entering the main oil passage. KDCB diesel engine gear oil pump is the lubrication power source of the whole engine. The performance of KDCB diesel engine gear oil pump directly affects the oil pressure.