Sensor Temperature Control Semi-Short Circuit Detection
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Solution Overview
Problem
Sensor temperature control apparatuses fail to detect short circuits between the heater section and switching devices, leading to inefficient energy use and potential device failure, as the temperature of the sensor element section can be maintained near the target temperature despite a short circuit with resistance, masking the anomaly.
Innovation Solution
A sensor temperature control apparatus that includes a switching device, energization control means, storage means for a first duty ratio in an un-shorted state, and semi-shorted state detection means to compare the present duty ratio with the stored duty ratio, allowing for proper detection of a semi-shorted state where only a portion of the current flows through the heater section.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the sensor temperature control apparatus uses feedback control to maintain the sensor element section at the target temperature, then the temperature control accuracy is improved, but the ability to detect semi-shorted states deteriorates because the temperature remains normal even when a short circuit with resistance exists
Solution Approach 1:
The invention introduces a feedback mechanism that monitors the duty ratio of the switching device and compares it with a predetermined reference value. When the duty ratio exceeds the reference value while the temperature is maintained at the target level, the system detects a semi-shorted state. This feedback approach allows the system to maintain accurate temperature control while simultaneously detecting abnormal current paths that would otherwise be masked by the temperature regulation.
2Temperature
If the switching device supplies current to the heater section, then the sensor element section is heated to the target temperature, but energy is wasted when a short circuit with resistance exists because current flows through both the heater and the short circuit path
Solution Approach 1:
The system uses feedback control to monitor the duty ratio and detect when it exceeds the reference value, indicating a semi-shorted state. Upon detection, the system can take corrective action to prevent continued energy waste, while the feedback mechanism itself enables the system to recognize and respond to the energy loss condition.
3Power
If the switching device operates at high current to maintain temperature, then the heating effect is improved, but the switching device may fail when the current reaches the upper limit due to voltage drop
Solution Approach 1:
The invention performs preliminary detection of the semi-shorted state by monitoring the duty ratio before the switching device reaches its current upper limit and fails. By detecting the abnormal condition early through duty ratio comparison, the system can take preventive action to protect the switching device from operating under harmful current conditions.
4Loss of energy
If the connection path has low resistance for efficient current flow, then the current flow is improved, but the ability to detect short circuits deteriorates because the short circuit resistance is not necessarily low due to contact resistance and wiring resistance
Solution Approach 1:
The system uses feedback monitoring of the duty ratio to detect semi-shorted states. By comparing the actual duty ratio with a predetermined reference value, the system can identify abnormal current paths even when their resistance is not significantly low, overcoming the limitation of resistance-based detection methods.
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
Enables accurate detection of a semi-shorted state, preventing energy wastage and potential device failure by distinguishing between un-shorted and semi-shorted states, ensuring the sensor element section is maintained at the target temperature.
Implementation Method 1
a heater section which heats the sensor element section
Implementation Method 2
a switching device which allows and prohibits supply of electricity to the heater section
Data Source
AI summary
A sensor temperature control apparatus (1) includes switching device (51); energization control means S1 and S2 for controlling duty ratio DT to maintain sensor element section (3) at a target temperature; storage means (75) for storing a first duty ratio DT1 in advance; element temperature judgment means S3 for determining whether the temperature of the sensor element section falls within a first temperature range including the target temperature; and semi-shorted state detection means S4 to S6 for comparing a present duty ratio DT2 with the first duty ratio in a state in which the temperature of the sensor element section falls within the first temperature range, to thereby determine whether a semi-shorted first temperature range state has arisen in which only a portion of the current flowing through switching device flows through heater section (4) and the temperature of the sensor element section falls within the first temperature range.