Vehicle Pyrotechnic Cutoff Circuit With Dual Overcurrent Detection
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Solution Overview
Problem
Conventional in-vehicle cutoff devices face reliability issues due to incorrect detection of overcurrent conditions, leading to inappropriate ignition or failure to ignite the pyrotechnic switch, which can result in unreliable operation.
Innovation Solution
The device incorporates two current detectors and a controller that receive signals from both detectors to determine if the current values exceed an overcurrent threshold, ensuring accurate detection and activation of the pyrotechnic circuit breaker for reliable cutoff operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single current detector is used to detect overcurrent conditions, then the device complexity is reduced, but the reliability of cutoff operations deteriorates due to incorrect detection
Solution Approach 1:
The patent applies local quality by placing current detectors at different locations in the circuit (first current detector in the first conductor wire between battery positive terminal and load, second current detector in the second conductor wire between battery negative terminal and load). Each detector monitors current from a different perspective, and their combined evaluation provides comprehensive overcurrent detection, resolving the contradiction between reliability and complexity.
2Measurement precision
If multiple current detectors are used to improve detection accuracy, then the reliability of cutoff operations is improved, but the device complexity increases
Solution Approach 1:
The patent merges the detection results from multiple current detectors through a controller that evaluates both detection signals together. The controller determines overcurrent conditions by analyzing the combination of signals from the first and second current detectors, achieving high measurement precision while managing device complexity through integrated signal processing.
Solution Approach 2:
The controller receives feedback signals from both current detectors and uses this information to make accurate cutoff decisions. The feedback mechanism allows the system to continuously monitor current conditions from multiple sources and respond appropriately, improving detection accuracy without proportionally increasing complexity.
Data Source
AI summary
An in-vehicle cutoff device includes a first input terminal, a first output terminal, a first conductor wire, a second input terminal, a second output terminal, a second conductor wire, a first current detector capable of detecting a current flowing through the first conductor wire or the second conductor wire, a second current detector capable of detecting a current flowing through the first conductor wire or the second conductor wire, a pyrotechnic circuit breaker capable of irreversibly disconnecting the first conductor wire, and controller capable of controlling a cutoff operation of the pyrotechnic circuit breaker in response to the detected currents. The controller causes the cutoff operation of the pyrotechnic circuit breaker to perform the cutoff operation when both of a first current value generated based on a first detection signal and a second current value generated based on the second detection signal exceed an overcurrent threshold.