Fuel Rail Pressure Regulating Valve Control for Engine Stability
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Solution Overview
Problem
Existing internal combustion engine injection systems face issues with periodic fluctuation of high pressure due to faulty suction throttles, leading to unstable engine operation and impaired emissions, and require additional mechanical pressure relief valves that increase costs and complexity.
Innovation Solution
Implementing a method where the pressure regulating valve operates in a second high-pressure regulating loop during protective mode, allowing for continuous regulation of high pressure and permanent dissipation of excess fuel, thereby eliminating the need for mechanical pressure relief valves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the protective function is temporarily activated when pressure threshold is exceeded, then high pressure increase is prevented, but periodic pressure fluctuations occur causing unstable engine operation
Solution Approach 1:
The control unit is configured to activate the protective function immediately when the dynamic high pressure exceeds the pressure threshold value, preventing periodic fluctuations by maintaining continuous protection during fault conditions rather than temporarily resetting
Solution Approach 2:
The system continuously monitors dynamic high pressure and adjusts the pressure regulating valve actuation accordingly, maintaining stable pressure regulation even during protective mode to prevent engine operation instability
2Reliability
If the pressure regulating valve is actuated to maximum opening in protective mode, then high pressure regulation is achieved, but fuel delivery becomes excessive leading to waste
Solution Approach 1:
The pressure regulating valve is actuated to a degree that is sufficient to maintain pressure regulation during protective mode without being excessively opened, optimizing the balance between reliable pressure control and fuel consumption by adjusting the valve opening based on actual pressure conditions rather than maximum opening
Data Source
AI summary
A method for operating an internal combustion engine having an injection system which has a high-pressure accumulator, wherein a high pressure in the high-pressure accumulator is regulated via a suction throttle on the low-pressure side as a first pressure control member in a first high-pressure control loop, wherein in a normal operation a high-pressure disturbance variable is produced via a pressure control valve on the high-pressure side as a second pressure control member, via which fuel is redirected from the high-pressure accumulator to a fuel reservoir. For this purpose, the high pressure in a safety operation is regulated by the pressure control valve via a second high-pressure control loop, or, in the safety operation, a maximum fuel volume flow is continuously redirected from the high-pressure accumulator to the fuel reservoir via the pressure control valve.