Door Sensor Failure Detection Using Dual-Signal Redundancy
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Solution Overview
Problem
Existing systems for automatic transmission in vehicles face challenges in detecting door state and sensor failures, particularly with shift-by-wire transmissions, leading to unpredictable behavior when the 'Return to Park' feature is disabled due to faulty door sensors, and proposed solutions are either ineffective or costly.
Innovation Solution
A system that includes a controller using both door latch and door lock sensors to determine the door state and detect sensor failures, adjusting the 'Return to Park' feature to rely on the door lock signal if the door latch sensor fails, with a fault counter and memory to track and manage sensor states and faults.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single door latch sensor is used to detect door state for Return to Park function, then the system is simple and low-cost, but the system cannot detect sensor failures leading to unpredictable behavior
Solution Approach 1:
The patent combines door latch sensor and door lock sensor into a unified door state detection system. The controller integrates signals from both sensors to determine door state, merging their functions to achieve redundant detection capability without requiring a completely separate system.
Solution Approach 2:
The door lock sensor serves dual purposes: it controls door locking/unlocking operations and simultaneously provides door state information for the Return to Park function. This multi-functionality allows the system to use existing components for multiple detection purposes, reducing the need for additional dedicated sensors.
2Productivity
If the system ignores a faulty door sensor and uses alternative sensors, then the Return to Park function can still operate, but the system behavior becomes unpredictable and unsafe
Solution Approach 1:
The controller implements continuous monitoring of door sensor signals and compares them against expected states based on door lock sensor feedback. When discrepancies are detected indicating sensor failure, the system provides feedback to switch to alternative detection methods, ensuring continuous safe operation.
Solution Approach 2:
The system pre-establishes alternative door state detection methods using the door lock sensor and door state memory. When a sensor failure is detected, the controller can immediately switch to these pre-prepared alternative methods without interruption to the Return to Park function.
3Device complexity
If electronic display is used to show transmission range in shift-by-wire systems, then the system is compact and modern, but the system requires continuous power and cannot provide tactile feedback
Solution Approach 1:
The patent combines electronic display indication with alternative door state detection methods. The controller integrates multiple information sources (door latch sensor, door lock sensor, door state memory) to provide reliable door state determination, merging these functions into a unified control system that enhances overall system reliability.
Solution Approach 2:
The door lock sensor serves multiple functions: controlling door locking operations and providing door state information for transmission control. This multi-functional approach allows the system to use existing components efficiently, reducing the need for additional dedicated sensors while maintaining reliable operation.
Data Source
AI summary
A system includes a controller that executes a method for determining failure of the door latch sensor using both the door latch sensor and a door lock sensor. If the door latch sensor is faulty, the controller adjusts an automatic feature of the vehicle based on a door lock signal instead of a door state signal. The controller is also configured to mark the door latch signal as faulty if the door latch system is not functioning properly by using a fault counter that tracks the door lock sensor.