Sensor Control Device Short Circuit Terminal Identification
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Solution Overview
Problem
Existing sensor control devices face difficulties in identifying short circuit terminals due to environmental conditions and require complex configurations, making it challenging to differentiate between short circuit and non-short circuit terminals in air-fuel ratio sensors.
Innovation Solution
A sensor control device with a short circuit detection unit, resistance value control unit, and temperature control unit that increases resistance or decreases temperature to identify short circuit terminals, allowing for simple configuration and operation unaffected by environmental conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sensor is warmed to a predetermined temperature or higher to enable gas concentration measurement, then the cell becomes active and measurement capability is improved, but the resistance value between terminals becomes smaller and voltage drop decreases, making it difficult to identify short circuit terminals
Solution Approach 1:
The system performs short circuit terminal identification before the sensor is warmed to operating temperature. By detecting short circuits in the cold state when resistance values are higher and voltage drops are more pronounced, the system can identify problematic terminals before they interfere with active measurement operations.
Solution Approach 2:
The system dynamically adjusts its detection strategy based on the sensor's operational state. It performs identification operations at different temperatures (cold and warm states) and uses temperature as a variable to change the electrical characteristics for better detection sensitivity at different phases.
2Difficulty of detecting and measuring
If an inspection potential circuit and special connection circuit are added to identify short circuit terminals, then terminal identification capability is improved, but the device configuration becomes more complex and identification operation is affected by environmental conditions
Solution Approach 1:
The existing sensor heating circuit is made multi-functional by using it both for its primary purpose (heating the cell for measurement) and for short circuit detection. The connection structures already present for normal sensor operation are utilized for identification operations, eliminating the need for separate dedicated detection circuits.
Solution Approach 2:
The sensor's own internal resistance characteristics and existing circuit structures are used to perform self-diagnosis. The system leverages the sensor's inherent electrical properties at different temperatures to identify short circuits without requiring external inspection equipment or additional protective circuitry.
3Measurement precision
If the sensor operates in an active state at predetermined temperature or higher, then gas concentration measurement accuracy is improved, but the voltage drop between terminals becomes smaller making short circuit detection more difficult
Solution Approach 1:
The system performs identification operations before the sensor is warmed to operating temperature. By detecting short circuits in the cold state when resistance values are higher and voltage drops are more pronounced, the system can identify problematic terminals before they interfere with active measurement operations.
Solution Approach 2:
The system performs identification operations at periodic intervals at different temperature states. It conducts detection during cold operation phases and again during warm operation phases, using the periodic temperature variations to create detectable voltage drop differences for identifying short circuit terminals.
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
Effectively identifies short circuit terminals with a simple configuration, ensuring accurate detection without environmental interference, thereby improving sensor control accuracy.
Implementation Method 1
The air-fuel ratio sensor is equipped with a heater because it is necessary to heat the cell at a predetermined temperature or higher for accurate measurement. The heater can keep the cell at the predetermined temperature or higher and can set the cell to an active state at an early stage.
Implementation Method 2
a resistance value control unit that increases a resistance value of an element between the terminals when the short circuit of the sensor is detected by the short circuit detection unit
Implementation Method 3
a temperature control unit that decreases a temperature of the sensor when the short circuit of the sensor is detected by the short circuit detection unit
Data Source
AI summary
To provide a sensor control device capable of identifying a short circuit terminal with a simple configuration and whose identification operation is not easily affected by environmental conditions around the sensor. The sensor control device includes a short circuit detection unit that detects a short circuit of a sensor having a plurality of terminals, a resistance value control unit that increases a resistance value of an element between the terminals when the short circuit of the sensor is detected by the short circuit detection unit, and a short circuit terminal identification unit that identifies at which of the plurality of terminals a short circuit occurs when the resistance value control unit increases the resistance value of the element between the terminals to a set value or greater.