High-Pressure Sensor Diagnosis via Signal Gradient Analysis
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Solution Overview
Problem
High-pressure sensors in motor vehicles often experience in-range errors due to drift, freezing, jumps, or noise in the measured rail pressure signal, leading to potential overpressure and system bursting, which existing solutions attempt to address with additional components like pressure relief valves or redundant sensors, incurring extra costs.
Innovation Solution
A method where the control unit evaluates the pressure measurement signal to detect in-range errors by checking differences between successive values, expected changes, and pressure gradients, using existing components without requiring additional hardware, thereby diagnosing high-pressure sensor issues and preventing overpressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional components like pressure relief valves or redundant sensors are used to address in-range errors, then system reliability is improved, but device complexity and cost increase
Solution Approach 1:
The control unit performs self-diagnosis of the high-pressure sensor by evaluating the pressure measurement signal against expected physical behavior. The system monitors itself without external diagnostic equipment, checking whether the difference between successive pressure values exceeds calculated maximum differences, whether the difference between minimum and maximum values in a time segment matches expected changes, and whether measured pressure gradients align with expected gradients based on fuel injection amounts and pump delivery.
Solution Approach 2:
The control unit continuously monitors the pressure measurement signal and compares it with expected values derived from fuel injection processes and pump activities. When deviations are detected (such as in-range errors where the sensor reading is within the technical range but physically implausible), the control unit can trigger diagnostic routines or adjust control parameters to maintain system reliability.
2Measurement precision
If additional components are added to detect and prevent in-range errors, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The existing control unit is utilized for diagnostic purposes, eliminating the need for additional diagnostic hardware. The control unit evaluates the pressure measurement signal using algorithms that compare measured values with physically expected values derived from fuel injection amounts, pump delivery characteristics, and system pressure dynamics.
Solution Approach 2:
The control unit serves multiple functions: it controls fuel injection, monitors pressure, performs diagnostic evaluations of the pressure sensor, and adjusts control parameters based on diagnostic results. This multi-functionality eliminates the need for dedicated diagnostic components, reducing manufacturing costs while maintaining measurement precision.
3Reliability
If the control unit performs comprehensive diagnostic checks, then reliability is improved, but use of energy increases
Solution Approach 1:
The diagnostic checks are performed periodically based on operational conditions rather than continuously. The control unit evaluates the pressure measurement signal at intervals determined by fuel injection events, pump cycles, and pressure change thresholds, reducing computational load and energy consumption while maintaining effective monitoring.
Solution Approach 2:
The control unit calculates expected pressure values and maximum permissible differences in advance based on fuel injection amounts and pump delivery characteristics. These preliminary calculations enable rapid comparison with actual sensor readings during operation, minimizing real-time computational requirements and energy consumption.
Data Source
AI summary
Various embodiments include a method for diagnosis of a high-pressure sensor of a motor vehicle comprising: measuring a pressure with the high-pressure sensor; feeding the measured pressure to a control unit; evaluating the measured pressure with the control unit and determining a control signal for an amount of fuel to be injected; checking whether a first difference between two successive values of the pressure measurement signal is greater than a calculated maximum difference value; checking whether a second difference between a minimum pressure measurement signal measured within a time segment and a maximum pressure measurement signal measured within the time segment is less than an expected change in the pressure measurement signal; and checking whether a measured pressure gradient is smaller than an expected pressure gradient.