Pressure Sensor Plausibility Check via Injector Current
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Solution Overview
Problem
Existing methods for checking the plausibility of pressure sensors in internal combustion engine injection systems are limited in detecting offset and gain errors, especially in real-time conditions, leading to inaccurate fuel injection and potential engine start issues, and are often costly due to the need for redundant monitoring.
Innovation Solution
A method involving a calibrated actuation profile to assign peak current values to internal pressures, monitoring the injection valve's opening state in response to applied electrical peak current values, and assessing the pressure sensor's functional state to detect offset and gain errors, with incremental reductions in current values to verify sensor accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If redundant monitoring with two pressure sensors is used, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The pressure sensor monitors its own functionality by comparing its measurements with physically plausible pressure ranges derived from system operating parameters (injector activation pressure, pump pressure). This self-diagnosis eliminates the need for redundant sensors while maintaining measurement precision through continuous plausibility checking of the single sensor's readings.
2Reliability
If pressure sensor plausibility checking is performed continuously, then reliability is improved, but use of energy increases
Solution Approach 1:
The plausibility checking is performed periodically at defined evaluation points during engine operation (e.g., at specific crankshaft positions or injection events) rather than continuously. This periodic evaluation maintains reliability by regularly verifying sensor functionality while significantly reducing energy consumption compared to continuous monitoring.
3Productivity
If the injection system operates with high pressure, then productivity is improved, but object-affected harmful factors increase
Solution Approach 1:
The system performs preliminary plausibility checks of the pressure sensor before critical high-pressure injection events occur. By evaluating sensor readings against expected pressure ranges in advance (e.g., before injection pulses), the system ensures accurate fuel injection efficiency while detecting and responding to potential sensor failures that could lead to harmful high-pressure malfunctions.
Data Source
AI summary
A method according to the invention for checking the plausibility of the function of a pressure sensor in an injection system of an internal combustion engine includes acquiring a calibrated actuation profile, by which peak current values for opening at least one electrically actuatable injection valve are assigned to existing internal pressures. An existing internal pressure is measured in the form of an actual sensor pressure value by the pressure sensor. The method includes obtaining the electrical peak current value corresponding to the measured sensor pressure value from a calibrated actuation profile, such that the corresponding electrical peak current value acquired in this way is applied to the injection valve. Subsequently, an opening state of the injection valve is monitored in reaction to the applied electrical peak current value, and a functional state of the pressure sensor is assigned as a function of the opening state of the injection valve.