Engine Rail Pressure Stabilization via Passive Valve Activation
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Solution Overview
Problem
After a rail pressure sensor failure in an internal combustion engine, the rail pressure does not consistently return to a stable level, leading to varying engine outputs in emergency operating mode.
Innovation Solution
Intentionally opening the passive pressure control valve to maintain rail pressure within a stable range (between 700 bars at full load and 900 bars at idle) by adjusting the suction throttle and high-pressure pump operation, and setting a mean rail pressure for injector energization time calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If open-loop control is used after rail pressure sensor failure, then the engine can continue operating, but the rail pressure does not consistently return to a stable level causing varying engine outputs
Solution Approach 1:
The control device intentionally opens the passive pressure control valve before the rail pressure can become unstable. By proactively activating the valve in a controlled manner, the system prevents pressure fluctuations and ensures the rail pressure stabilizes at a predictable level, eliminating the variability in engine output that would otherwise occur during sensor failure.
2Stability of the object's composition
If the passive pressure control valve is intentionally opened, then rail pressure is maintained within a stable range, but the engine output may be limited compared to normal operation
Solution Approach 1:
The control device changes the operating parameters of the passive pressure control valve by adjusting the suction throttle position and high-pressure pump operation. By optimizing these parameters, the system maintains rail pressure within a stable range (700-900 bars) while maximizing engine output within the constraints of the opened valve, achieving the best possible performance under emergency operating mode.
3Ease of operation
If a transition function is used to switch from closed-loop to open-loop control, then the control transition is smooth, but the rail pressure does not always swing back to the same pressure level
Solution Approach 1:
The control device uses feedback from the engine operating conditions (engine speed, load, temperature) to dynamically adjust the passive pressure control valve opening. This feedback mechanism ensures that the rail pressure consistently returns to the same stable level after sensor failure, eliminating the variability that would otherwise occur during transition to emergency operating mode.
Data Source
AI summary
The invention relates to a method for the open-loop control and the closed-loop control of an internal combustion engine (1), the rail pressure (pCR) being controlled in a closed loop mode in the normal operating state and an emergency operation mode being activated once a defective rail pressure sensor (9) is detected, in which emergency operation the rail pressure (pCR) is controlled in an open loop mode. The invention is characterized in that in the emergency operation mode, the rail pressure (pCR) is gradually increased until a passive pressure relief valve (11) is activated which redirects fuel from the rail (6) to the fuel tank (2) when it is open.