Common Rail Sensor Defect Detection via Control Deviation
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Solution Overview
Problem
Current methods for operating internal combustion engines with common rail injection systems fail to reliably detect defects in high-pressure sensors, leading to unstable engine behavior and increased mechanical stress due to incorrect pressure control, which can result in engine shutdown or cyclical oscillations.
Innovation Solution
A method is developed to detect high-pressure sensor defects by checking if the measurement value remains constant or varies within a limited range, allowing for differentiated diagnostics and targeted measures to ensure reliable engine operation, without requiring additional sensors, thereby improving robustness and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a high-pressure sensor is used to detect fuel pressure in the common rail system, then pressure measurement capability is improved, but reliability of sensor operation deteriorates due to undetected defects causing unstable engine behavior
Solution Approach 1:
The patent implements a feedback mechanism where the control unit continuously monitors the output signal of the high-pressure sensor and compares it against expected pressure ranges and变化 patterns. When the sensor output deviates from the expected feedback range or shows abnormal patterns (such as constant values despite pressure changes), the system detects the defect and switches to emergency operation mode, thereby maintaining reliability while preserving measurement precision.
Solution Approach 2:
The system performs self-diagnosis by using the existing high-pressure sensor and control unit to monitor its own operational status. The control unit analyzes the sensor's output signals to detect defects without requiring external monitoring equipment, enabling the system to identify and respond to sensor failures autonomously through emergency mode activation.
2Reliability
If additional sensors are added to detect high-pressure sensor defects, then reliability is improved, but device complexity increases
Solution Approach 1:
The control unit is designed to serve multiple functions: it not only controls the injection system but also monitors the high-pressure sensor's operation and detects defects. The existing sensor infrastructure is used for dual purposes - both measuring fuel pressure for injection control and monitoring sensor health for defect detection - thereby improving reliability without adding dedicated monitoring sensors or increasing system complexity.
Solution Approach 2:
The system uses its existing components (high-pressure sensor and control unit) to perform self-diagnosis. The control unit analyzes the output signals from the high-pressure sensor to detect defects, eliminating the need for additional monitoring sensors or diagnostic equipment, thus maintaining device simplicity while enhancing reliability through defect detection capabilities.
3Reliability
If the engine operates in emergency mode due to sensor defect detection, then reliability is improved by preventing damage, but productivity decreases due to restricted operation
Solution Approach 1:
The system prepares for potential sensor failures by having a pre-defined emergency operation mode ready. When a sensor defect is detected, the control unit immediately switches to this pre-prepared emergency mode, which restricts engine operation to safe parameters. This beforehand preparation allows the system to protect the engine from damage while maintaining limited operational capability, balancing reliability improvement with productivity preservation.
Data Source
AI summary
A method for operating an internal combustion engine with a motor having a number of cylinders and an injection system having a common rail with a number of injectors assigned to the cylinders and similar high pressure components, which is designed to hold fuel from the common rail for the injector, wherein the method has the steps: injecting fuel from the common rail into a cylinder by way of an injector, determining a fuel pressure for a high-pressure component, in particular the common rail, the injector and/or the individual reservoir, having at least one high-pressure sensor measuring the fuel pressure. Provision is made for a defect in the high-pressure sensor to be detected in that a check is made as to whether magnitude of the high-pressure control deviation (ep) during a predetermined time interval (tLimit1SD, tLimit2SD, tLimit3SD) exceeds a predetermined limiting value (eLimit1SD, eLimit2SD, eLimit3SD).