Ignition Switch Circuit Layout for Intermediate Key Position Detection
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Solution Overview
Problem
Existing motor vehicle ignition switches lack detailed detection of the intermediate key position, which is crucial for safety and operational reliability, especially in compact designs with limited components.
Innovation Solution
A motor vehicle ignition switch incorporating two independent electric circuits and an electronic control unit to determine the key position, activate functions, and control a locking pin, providing a distinct warning signal for the intermediate position and ensuring the key is not removed unless in the parking position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a compact ignition switch design is used with limited components, then the device complexity is reduced, but the measurement precision of key position detection deteriorates
Solution Approach 1:
The patent combines multiple detection functions into a single integrated switch body. The first and second electric circuits are integrated within the same housing, sharing common components such as the rotating element and magnetic field generation structures. This merging allows the system to detect multiple key positions (intermediate and final) without proportionally increasing the number of discrete components, thus maintaining compactness while achieving precise multi-position detection.
Solution Approach 2:
The rotating element serves multiple functions: it acts as both the mechanical indicator of key position and the trigger for magnetic field changes detected by both electric circuits. The single switch body performs detection, signal generation, and position indication functions simultaneously. This multi-functionality reduces the need for separate dedicated components for each detection task, resolving the contradiction between component count and detection precision.
2Reliability
If detailed detection of intermediate key position is implemented, then the reliability of key position detection is improved, but the device complexity increases
Solution Approach 1:
The patent replaces complex mechanical position detection mechanisms with magnetic field-based electric circuits. Instead of using multiple mechanical switches or sensors that would require complex physical structures, the invention uses changes in magnetic field strength detected by electromagnetic circuits to determine key position. This substitution achieves reliable detection of intermediate positions without proportionally increasing mechanical complexity.
Solution Approach 2:
The patent introduces a magnetic field as an intermediary between the mechanical key rotation and the electrical detection system. The rotating element with magnetic elements creates field changes that mediate the transmission of position information to the electric circuits. This intermediary approach allows reliable position detection while keeping the mechanical structure simple, as the magnetic field carries the positional information without requiring complex mechanical linkages.
3Reliability
If a locking pin mechanism is added to prevent key extraction, then the safety is improved, but the device complexity increases
Solution Approach 1:
The locking pin is designed as a dynamic component that automatically transitions between locked and unlocked states based on detected key position. Rather than requiring a separate control system or multiple actuators, the locking pin responds dynamically to the presence or absence of the key in the ignition switch. This dynamic behavior achieves safety functionality without adding complex control mechanisms.
Solution Approach 2:
The locking mechanism is designed to self-regulate based on key position detection. When the key is present and rotated to the appropriate position, the system automatically engages or disengages the locking pin without requiring external intervention or complex control logic. This self-service approach maintains safety while minimizing additional components, as the existing detection circuits directly control the locking state.
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 enables reliable detection of key positions with a compact design, enhancing safety by preventing key extraction unless in the parking position, while maintaining operational reliability and simplicity.
Implementation Method 1
a first electric circuit (26) for determining whether the key (4) is in an intermediate position between the vehicle off position and the running position
Implementation Method 2
a second electric circuit (27) for determining whether the key (4) is in the running position
Implementation Method 3
The translation of the locking pin is generally obtained by means of an electromagnet
Data Source
AI summary
A motor vehicle ignition switch has a first and a second electrical circuit for detecting the angular position of a key in an ignition lock, with a rotor that is rotatable about a rotation axis so as to be able to selectively take an off position, a starting position, a running position, an on position and an intermediate position, distinct from each other; the second circuit is independent of the first circuit and defines a resistive divider; the first circuit has a first, a second and a third conductive laminas, electrically isolated from each other; the first circuit has two contacts, one of which is arranged on the third lamina in the running position and in the starting position and on the first lamina in the intermediate position.