Temperature Sensor Testing via Voltage Pulse
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Solution Overview
Problem
Existing temperature sensors in vehicles, particularly resistive temperature sensors, face challenges in ensuring accuracy and preventing manipulation, especially in meeting legal requirements for temperature measurement in heavy vehicles, where accuracy and reliability are critical, and there is a risk of sensor tampering.
Innovation Solution
A method involving a voltage pulse is applied across the temperature sensor to diagnose its functionality, calibrate its measurement, and detect any offset errors, allowing for verification of temperature dependency and prevention of manipulation by measuring resistance differences before and after the pulse, with thresholds for validation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a voltage pulse is applied to the temperature sensor to heat it for testing, then the temperature dependency can be verified and manipulation detected, but the sensor may be damaged by excessive heating
Solution Approach 1:
The patent applies a voltage pulse of limited duration (less than 1 second) to heat the temperature sensor for testing. This periodic/pulsed action allows the sensor to be heated sufficiently to verify temperature dependency and detect manipulation, while the limited duration prevents excessive heating that could damage the sensor.
Solution Approach 2:
The patent uses a voltage pulse with predetermined amplitude and duration that provides just enough heating to verify sensor functionality and detect manipulation, without applying excessive energy that would cause damage. The testing approach uses partial action (brief pulse) rather than continuous heating.
2Measurement precision
If the voltage pulse duration is extended to ensure adequate heating for accurate testing, then temperature dependency verification improves, but the risk of sensor damage increases
Solution Approach 1:
The patent employs a voltage pulse with predetermined duration of less than 1 second. This pulsed approach provides sufficient heating to verify temperature dependency accurately while limiting the time exposure to prevent sensor damage, resolving the contradiction between measurement precision and sensor integrity.
Solution Approach 2:
The patent optimizes the voltage pulse parameters (amplitude and duration) to achieve the right balance. By carefully selecting the pulse duration to be less than 1 second and the amplitude to be sufficient for heating but not excessive, the method achieves accurate temperature dependency verification while maintaining sensor integrity.
3Reliability
If multiple redundant temperature sensors are installed to meet legal requirements and prevent manipulation, then reliability improves, but device complexity and cost increase
Solution Approach 1:
The patent enables a single temperature sensor to perform self-diagnosis and self-verification through the voltage pulse testing method. The sensor tests its own temperature dependency and can detect its own manipulation, eliminating the need for multiple redundant sensors and reducing system complexity while maintaining reliability.
Solution Approach 2:
The patent implements a feedback mechanism where the control unit measures the resistance change of the temperature sensor in response to the voltage pulse and compares it against expected values. This feedback allows verification of sensor functionality and detection of manipulation, providing reliability without requiring redundant sensors.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables accurate temperature measurement calibration, prevents sensor manipulation, and eliminates the need for redundant sensors, ensuring compliance with legal requirements and enhancing measurement reliability.
Implementation Method 1
develop power in the sensor by applying a voltage pulse across it... When energy is supplied, the temperature of the sensor will also rise
Data Source
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AI summary
The invention relates to a method for testing a temperature sensor which comprises a temperature-dependent resistor (R2). The method comprises the steps of - determining the resistance Rt1 for R2, - applying to the resistor R2 a voltage pulse with a predetermined voltage amplitude Ut and a predetermined duration T, - determining the resistance Rt2 for R2 after the voltage pulse, - determining the absolute value of the resistance difference AR = | Rt1 - Rt2 |, - comparing AR with one or more threshold values (TR1, TR2,...), - generating on the basis of the result of the comparison a test signal which represents the result of the testing of the temperature sensor.