Semiconductor Impact Sensor for High-Voltage Interruption
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Solution Overview
Problem
Existing motor vehicles with high-voltage electric systems face challenges in reliably interrupting the high-voltage power supply during accidents without causing malfunctions, particularly due to tampering or passive accidents, and existing solutions either require additional sensors or fail to differentiate between airbag activation and high-voltage system damage criteria.
Innovation Solution
A motor vehicle system incorporating a semiconductor impact sensor, a safing sensor, and a control unit that outputs signals to interrupt the high-voltage power supply based on specific criteria, including independent impact sensing and evaluation of semiconductor sensor outputs to prevent malfunctions and tampering, without the need for additional sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the air bag impact sensor is used to interrupt the high-voltage system, then the high-voltage system can be interrupted when a seat belt alone can cause injury to a passenger, but the interruption is insufficient because the air bag impact sensor is configured to inflate an air bag only when a seat belt alone can cause injury to a passenger
Solution Approach 1:
The patent divides the impact detection function into two separate systems: one for air bag activation and another for high-voltage system interruption. This segmentation allows each system to have its own dedicated sensor and evaluation criteria, resolving the contradiction by enabling the high-voltage interruption system to detect impacts that may damage the high-voltage system even when they are insufficient to trigger air bag inflation.
Solution Approach 2:
The patent applies different evaluation criteria to different impact scenarios. The air bag impact sensor uses a threshold based on passenger injury risk, while the high-voltage system interruption uses a separate threshold based on high-voltage system damage risk. This local quality approach allows each subsystem to optimize its detection sensitivity for its specific safety requirements.
2Reliability
If an additional impact sensor is provided to prevent malfunction, then the high-voltage power supply can be interrupted more reliably, but the cost increases and mounting space is required
Solution Approach 1:
The patent makes the air bag impact sensor serve multiple functions: it continues to control air bag inflation while also providing data for high-voltage system interruption decisions. By evaluating the sensor output against different criteria in different contexts, the system achieves reliable high-voltage interruption without adding physical sensors, thus avoiding increased device complexity and cost.
Solution Approach 2:
The patent changes the evaluation parameter (threshold criteria) rather than adding hardware. The same impact sensor output is evaluated against different thresholds depending on the intended action: a higher threshold for air bag inflation and a lower threshold for high-voltage system interruption. This parameter-based differentiation resolves the reliability need without increasing device complexity.
3Ease of operation
If criteria are adopted to exclude tampering cases (parking range, neutral range, low speed), then the high-voltage system interruption can be prevented during normal operation, but the high-voltage power supply cannot be interrupted in passive accidents during temporal stop or when changing shift position to neutral range
Solution Approach 1:
The patent changes the evaluation criterion from considering vehicle operating state (shift position, speed) to considering only the impact sensor output magnitude. By removing the operating state constraints, the system can detect passive accidents regardless of vehicle speed or shift position, while still preventing false positives by using an appropriately calibrated impact threshold that distinguishes genuine impacts from normal vibrations.
4Reliability
If the high-voltage system is interrupted when air bag is not required, then safety is improved, but unnecessary interruptions occur causing loss of vehicle mobility
Solution Approach 1:
The patent uses different impact thresholds for different actions: a higher threshold for air bag inflation and a lower threshold for high-voltage system interruption. This parameter differentiation ensures that only impacts severe enough to potentially damage the high-voltage system trigger interruption, avoiding unnecessary interruptions during minor impacts that would not threaten system safety, thus preserving vehicle mobility while maintaining safety.
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
The system effectively interrupts the high-voltage power supply when necessary, preventing malfunctions and tampering, while avoiding unnecessary interruptions during passive accidents or when an airbag is not required, thus enhancing safety and reducing costs.
Implementation Method 1
The first control unit includes a semiconductor impact sensor
Data Source
AI summary
An output of a semiconductor impact sensor contained in an air bag ECU is used to make determination in light of a criterion for interrupting a high-voltage power supply, which is different from a criterion for inflating an air bag so that the semiconductor impact sensor forms a redundant system along with a conventional safing sensor to prevent malfunction. Furthermore, an output of the semiconductor impact sensor contained in the air bag ECU is used to make determination for safing and output a safing signal thereby, so that a redundant system can be formed for a front impact sensor, a side impact sensor, and a rear impact sensor. Accordingly, malfunction can be prevented when tampering such as a strike with a hammer occurs.