Return oil system of high-pressure common rail pump

Abstract

The invention discloses a return oil system of a high-pressure common rail pump. The return oil system comprises a common rail pump body, a low-pressure oil circuit and a return oil circuit; three plungers are arranged inside a pump cavity radially at even intervals, and a camshaft is arranged at the center of the common rail pump body and drives the three plungers to suck and press oil; part of fuel enters the pump cavity via the low-pressure oil circuit to lubricate moving parts inside the pump cavity; the return oil circuit is communicated with the pump cavity, a pressure regulating valve is arranged in the return oil circuit, and when fuel pressure in the pump cavity reaches a threshold of the pressure regulating valve, the fuel returns through the return oil circuit. By the system, enough fuel is available in the pump cavity to lubricate and cool the moving parts inside the pump cavity, meanwhile, the volume of the pump can be reduced, and the mounting space for the pump body on the engine is reduced.

Description

technical field [0001] The invention relates to the field of high-pressure common rail engines, in particular to an oil return system of a high-pressure common rail pump. Background technique [0002] In a traditional high-pressure common rail pump, a pipe joint or oil return screw is installed on the pump body at the oil return position, and the pipe joint or oil return screw is connected to the oil return line for oil return. Since the oil return line of this oil return system is connected smoothly, when the engine is running at low speed, the amount of fuel leakage is large, and the leakage location mainly includes the rotor of the oil delivery pump, the plunger coupling of the high pressure oil pump or the bearing bush of the high pressure oil pump. [0003] The existing high-pressure common rail pump oil return system will bring the following technical problems: First, when the engine is running at low speed, such as when starting, the overall efficiency of the common r...

AI Technical Summary

Problems solved by technology

[0003] The existing high-pressure common rail pump oil return system will bring the following technical problems: First, when the engine is running at low speed, such as when starting, the overall efficiency of the common rail pump is reduced, and most of the fuel leaks out through the oil return line, resulting in high pressure. There is not enough fuel in the pump chamber of the oil pump to lubricate and cool the sliding parts, such as the plunger coupling in the plunger pump, which may easily cause the moving parts to be stuck and damaged

In addition, the amount of fuel provided by the fuel pump is much greater than the fuel actually required by the engine, resulting in waste, and additional power is added to drive the fuel pump to work

Images