Clamping stagnation fault diagnosis method for oil rail mechanical pressure release valve and fuel system

Abstract

The invention relates to a clamping stagnation fault diagnosis method for an oil rail mechanical pressure release valve. The method comprises the following steps of checking whether a rail pressure sensor has a fault or not; collecting a rail pressure value of a high-pressure common rail pipe and comparing with a rail pressure upper limit threshold value of the high-pressure common rail pipe; judging continuous time; judging that a temperature rise value of the tail gas is greater than a temperature rise upper limit threshold value; enabling an engine to be in a limping mode; conducting oil reduction or oil cut-off operation; and sending a clamping stagnation fault signal of the oil rail mechanical pressure release valve. The invention further relates to a fuel system. A high-pressure oil pump is connected with the high-pressure common rail pipe; a high-pressure oil pump electromagnetic valve is coupled with an engine electronic control unit; the high-pressure common rail pipe is connected with an oil sprayer; the rail pressure sensor is coupled with the engine electronic control unit; the oil injector is coupled with the engine electronic control unit; the oil tank is connected with a low-pressure oil delivery pump; and the low-pressure oil delivery pump is connected with the high-pressure oil pump. According to the clamping stagnation fault diagnosis method for the oil rail mechanical pressure release valve and the fuel system provided by the invention, the situation that the judgment is more accurate based on the assumption that the rail pressure sensor has no fault is avoided; and accurate judgment can still be carried out when the rail pressure sensor breaks down.

Description

technical field [0001] The invention relates to the technical field of a diesel engine fuel system, in particular to a fault diagnosis method for a sticking fault of a mechanical pressure relief valve of a fuel rail and a fuel system. Background technique [0002] With the continuous upgrading of emission regulations, the accuracy and requirements of diesel engine control systems continue to increase; and the electronically controlled high-pressure common rail system is a set of fuel system control devices widely used in the field of diesel engine control. Injection pressure, and can independently and flexibly control the injection timing, injection pulse width, and fuel injection volume, so that it can achieve the ideal working condition for diesel combustion under different working conditions, realize the ideal injection effect, and reduce emissions At the same time, fuel economy and engine power performance are greatly improved. [0003] In the high-pressure common rail ...

AI Technical Summary

Problems solved by technology

[0012] 1. Because in actual work, the solenoid valve of the high-pressure oil pump is in an open-loop control state during the flushing process of the oil rail mechanical pressure relief valve, it is actually impossible to monitor the actual flow of the high-pressure pump in real time, and it is also impossible to pass through the high-pressure pump. The flow rate is used as a parameter to judge whether the fuel rail mechanical pressure relief valve is faulty; in other words, the application is only theoretically feasible;

[0013] 2. Since the technical solution monitors the fuel pressure in the high-pressure common rail pipe, the premise is that the rail pressure sensor has no faults, so when the rail pressure sensor fails, it cannot be diagnosed that the oil rail mechanical pressure relief valve is stuck when the valve is flushed. situation

[0017] Since the technical solution monitors the fuel pressure in the high-pressure common rail pipe, the premise is that the rail pressure sensor has no faults, so when the rail pressure sensor fails, it is impossible to diagnose the fuel rail mechanical pressure relief valve stuck when flushing the valve. Condition

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