Vehicle Sensor System Power Management for Crash Reliability
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Solution Overview
Problem
Existing pedestrian protection systems in vehicles face issues with short circuits in sensor connections during crashes, leading to high short-circuit currents that can overwhelm the power supply and reduce the effectiveness of the personal protection system.
Innovation Solution
The system differentiates between collisions with pedestrians and other objects, selectively switching off or reducing power to pedestrian protection sensors during vehicle crashes with other objects, thereby preventing unnecessary short-circuit currents and conserving energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the interface provides short-circuit current for a specified period to meet robustness requirements, then the reliability of the personal protection system is improved, but the energy consumption and power supply burden increase significantly
Solution Approach 1:
The patent applies dynamics by making the short-circuit current provision time variable rather than fixed. The interface unit dynamically adjusts the duration of short-circuit current based on the determined crash type: for pedestrian crashes, it provides current for at least 10 ms as required by PSI standards, while for other object crashes, it switches off power supply to pedestrian protection sensors immediately or after a brief delay, thereby avoiding unnecessary energy consumption while maintaining required reliability
Solution Approach 2:
The patent changes the parameter of current provision time based on crash type detection. By evaluating the physical quantity data to determine whether a pedestrian crash or other object crash occurred, the system adjusts the electrical parameter (current provision duration) accordingly, optimizing the balance between reliability and energy consumption
2Reliability
If power supply is maintained for all sensors during driving operation, then the reliability requirement of at least 10 ms current provision is met, but energy is wasted when sensors are not needed
Solution Approach 1:
The patent applies local quality by differentiating the power supply treatment for different sensor groups based on their function and the detected crash type. The interface unit selectively maintains power supply to sensors that are relevant to the current situation (e.g., occupant protection sensors during all crashes, pedestrian protection sensors only during pedestrian crashes) while switching off power to irrelevant sensors, thereby optimizing energy distribution locally rather than applying a uniform power supply policy
3Measurement precision
If multiple pedestrian protection sensors are connected to the control unit, then the detection capability is improved, but the potential short-circuit current accumulation increases
Solution Approach 1:
The patent applies segmentation by dividing the sensor system into functionally separate groups: pedestrian protection sensors and occupant protection sensors. The interface unit independently controls power supply to each group based on the detected crash type. This segmentation allows the system to maintain multiple sensors for improved detection capability while limiting short-circuit current accumulation by selectively powering off irrelevant sensor groups during specific crash scenarios
Data Source
AI summary
The sensor system has sensor units (3,5) arranged in the vehicle front area (1) and comprising sensors (FS1,FS2,FS3,FS4,UF1,UF2) for detecting a physical quantity. An evaluation- and control unit (20) evaluates the detected physical quantity for crash detection. An interface unit (30) supplies the sensor of the sensor unit with power and transmits electrical signals from the sensor to the evaluation- and control unit, where the electrical signals represent the detected physical quantity. The evaluation- and control unit turns off or turns on a current flow for the individual sensors depending on the determined driving condition during the driving operation by the interface unit or reduces a short-circuit current provided for the sensors.