A method for preventing rail pressure overshoot control of a static oil return fuel injector engine

By using ECU diagnostics and control strategies, combined with pressure relief and static air injection strategies, the rail pressure overshoot problem of engines without static return fuel injectors was solved, ensuring that the rail pressure is within a reasonable range. This also resolved the difficulties in opening the pressure relief valve and starting the engine, achieving rapid engine response and good control.

CN121474006BActive Publication Date: 2026-07-24TIANJIN UNIV +1
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
TIANJIN UNIV
Filing Date
2025-12-31
Publication Date
2026-07-24

AI Technical Summary

Technical Problem

In electronically controlled high-pressure common rail fuel systems without static return fuel injectors, rail pressure overshoot during long reverse driving can cause the pressure relief valve to open. Rail pressure overshoot can also occur during rapid deceleration or sudden load relief. After shutdown, excessively high or low rail pressure can lead to starting difficulties, especially in low-temperature environments. Furthermore, there is a problem of continuous rail pressure rise under low-load conditions.

Method used

By diagnosing engine faults through the ECU, the engine is controlled to execute multiple drag or static air injection strategies, pressure relief strategies, and a one-way relief valve is installed in the return oil manifold to ensure that the rail pressure is within a reasonable range. The rail pressure is adjusted during the power-down delay period in combination with the pressure relief strategy and the static air injection strategy to prevent the pressure relief valve from opening and starting difficulties.

Benefits of technology

It effectively solves the problems of pressure relief valve opening and starting difficulties caused by rail pressure overshoot, ensuring fast engine power response under transient conditions, avoiding pressure relief valve opening and black smoke, and achieving good rail pressure control and engine power, especially in low temperature environments.

✦ Generated by Eureka AI based on patent content.

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Abstract

The present application relates to the technical field of engine, and particularly discloses a rail pressure overshoot prevention control method for a static oil return fuel injector engine, which comprises the following steps: after the ECU receives a power-on instruction, diagnosing whether the engine has a fault; when the ECU diagnoses that the engine has no fault, judging whether the actual rail pressure of the engine meets the requirements; if the actual rail pressure of the engine does not meet the requirements, performing multiple drag operations on the engine or executing a static idle injection strategy during a power-off delay period of the engine until the actual rail pressure of the engine meets the requirements; if the actual rail pressure of the engine meets the requirements, controlling the engine to start normally; and after the engine starts successfully, performing an overshoot prevention control on the actual rail pressure of the engine. The present application effectively prevents the engine from emitting black smoke due to high load and low rail pressure caused by valve impact, effectively solves the problems of insufficient power and deteriorated in-cylinder combustion, and avoids the problem of excessively high oil tank temperature caused by a large amount of oil return.
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