Electronic Latch Handle Switch Reading Circuit
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Solution Overview
Problem
Existing electrical door latch systems in motor vehicles face challenges in controlling door opening and closing, especially during power failures or accidents, and handle switch failures can lead to incorrect detection and safety issues due to complex and inadequate diagnostic schemes.
Innovation Solution
An electronic control circuit with a handle switch reading circuit that converts DC voltage to AC and uses a capacitor to produce an output waveform for determining the handle switch position and detecting faults, including a series capacitor and DC-to-AC converter, connected to a control unit for accurate diagnostics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a wired connection is used between handle switches and control units, then the door latch system can detect handle position, but the wiring may fail or become shorted leading to safety issues
Solution Approach 1:
The patent replaces the mechanical/wired connection system with an inductive coupling system using magnetic fields. The handle switch assembly and door latch control unit communicate through electromagnetic induction without physical wire connections, eliminating wiring failures and short circuits while maintaining reliable position detection.
Solution Approach 2:
The patent introduces magnetic fields as an intermediary medium for communication between the handle switch assembly and door latch control unit. This intermediary allows information transfer without direct electrical contact, preventing wiring-related failures while enabling reliable signal transmission.
2Measurement precision
If complex diagnostic schemes are used to detect handle switch failures, then more faults can be detected, but the system complexity increases
Solution Approach 1:
The patent implements self-service diagnostics where the system automatically detects and identifies handle switch failures through the inductive coupling mechanism. The control unit monitors the integrity of the magnetic field coupling and automatically determines fault conditions without requiring complex external diagnostic equipment or procedures.
Solution Approach 2:
The patent uses feedback through the inductive coupling system to continuously monitor the operational status of the handle switch assembly. The control unit receives real-time information about switch position and coupling integrity, enabling automatic fault detection and diagnosis through the same communication channel used for normal operation.
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 solution effectively detects all possible dangerous faults in the handle switch and latch assembly, preventing unwanted door opening and ensuring occupant safety by providing reliable diagnostics and operation even in emergency situations.
Implementation Method 1
a handle capacitor in parallel with the handle switch. The handle switch reading circuit is adapted to supply an AC voltage to the handle switch subassembly. Additionally, the handle switch reading circuit is adapted to produce an output voltage waveform at the common node corresponding to the charging and discharging of the handle capacitor
Data Source
AI summary
An electronic latch for a motor vehicle closure system with an electronic control circuit including a handle switch reading circuit for a two-pin handle switch and a method of operating the handle switch reading circuit are disclosed. The electronic control circuit includes a control unit. The handle switch reading circuit is controlled by the control unit for coupling with a handle switch subassembly. The handle switch reading circuit is adapted to supply an AC voltage to the handle switch subassembly and produce an output voltage waveform corresponding to the charging and discharging of a handle capacitor of the handle switch subassembly and in response to a handle switch of the handle switch subassembly being operated. The handle switch reading circuit determines a position of the handle switch and presence of faults in the handle switch reading circuit and the handle switch subassembly based on the output voltage waveform.