Pinch Sensor and Gas Spring Integration for Liftgate Position
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Solution Overview
Problem
Current powered liftgate systems in motor vehicles require separate components for detecting pinch conditions and determining the full open position, leading to increased costs and complexity, as they lack an efficient method to integrate these functions without losing position memory when the controller goes to sleep.
Innovation Solution
A system utilizing left and right pinch sensors coupled with gas springs, where the gas springs' extensions compress the pinch sensors to determine the full open position by detecting simultaneous compression and calculating the time period between pinch signals, eliminating the need for a separate full open switch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate full open switch and pinch sensor components are used, then reliable full open position detection and pinch protection are achieved, but system cost and complexity increase
Solution Approach 1:
The patent combines the full open position detection function and pinch protection function into a single integrated system using one pinch sensor that serves dual purposes. The pinch sensor normally detects pinch conditions during liftgate operation, and simultaneously serves as the full open position indicator when activated by the gas spring extension, eliminating the need for a separate full open switch.
Solution Approach 2:
The pinch sensor is designed to perform multiple functions: it detects pinch conditions during normal operation and also indicates full open position when compressed by the gas spring extension. This multi-functional use of a single component reduces system complexity while maintaining reliability of both functions.
2Measurement precision
If separate full open switch is used, then full open position is accurately identified, but system cost increases
Solution Approach 1:
The pinch sensor serves dual purposes by detecting both pinch conditions during operation and full open position through compression by the gas spring extension. This eliminates the need for a separate full open switch while maintaining detection accuracy for both functions.
Solution Approach 2:
The gas spring extension automatically activates the pinch sensor at the full open position without requiring additional actuators or switches. The system uses its own existing components (gas spring and pinch sensor) to achieve position detection, eliminating the need for separate dedicated components.
3Loss of information
If controller remains active to maintain position memory, then full open position control is maintained, but energy consumption increases
Solution Approach 1:
The system uses the pinch sensor to detect the full open position in advance and set a flag in the controller's memory before the controller goes to sleep. This preliminary detection allows the controller to resume operation with position information already available, eliminating the need to remain active to maintain position memory.
Solution Approach 2:
The pinch sensor provides feedback about the full open position to the controller, which stores this information in memory. This feedback mechanism allows the controller to know the liftgate position even after sleeping, as the position information has been captured and stored during the brief period when the controller was active.
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
This solution allows for cost-effective determination of the full open position and controlled operation of the liftgate, preventing damage from obstacles and maintaining energy conservation by integrating pinch sensing and full open position detection within existing circuitry, reducing unnecessary components and expenses.
Implementation Method 1
each of the gas springs has an extension at an end thereof for compressing the corresponding pinch sensor when the closure member is at its full open position
Data Source
AI summary
A method and system for determining a full open position of a closure member of a motor vehicle that articulates between an open position and a closed position includes a left pinch sensor coupled to the left side of the closure member for sensing a pinch condition on the left side of the closure member and generating a corresponding pinch signal. A right pinch sensor is coupled to the right side of the closure member for sensing a pinch condition on the right side of the closure member and generating a corresponding pinch signal. Left and right gas springs are coupled respectively to the left and right sides of the closure member for assisting in articulating the closure member and each of the gas struts has an extension at an end thereof for compressing their corresponding pinch sensor when the closure member is at its full open position.