Motor Vehicle Ignition Lock Using Magnetic Angle Encoder

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Solution Overview

Problem

Conventional ignition locks are complex and cost-intensive due to the use of conventional electrical switches on the rotor, requiring a large size that may not fit in all vehicles, and have issues with power consumption and assembly complexity.

Innovation Solution

The ignition lock employs an angle encoder as a signal-generating element, utilizing a leaf spring for detents and a magnetic field sensor for power efficiency, with dynamic clocking and software-defined switching positions, and integrates a coil carrier for energy transfer, reducing parts and improving ergonomics and security.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional electrical switches on the rotor are used as signal generating elements, then the ignition lock can generate vehicle electrical system signals, but the device complexity and cost increase

Engineering Contradiction:
Improvesignal generation reliabilityVSAvoidignition lock complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces conventional electrical switches with a magnetic field sensor that detects the position of a magnet on the rotor. This substitution eliminates the need for complex mechanical switch articulation while maintaining reliable signal generation. The magnetic field sensor generates vehicle electrical system signals based on the rotor's angular position without requiring physical contact or complex mechanical articulation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If conventional electrical switches on the rotor are used, then signal generation is possible, but the ignition lock size increases

Engineering Contradiction:
Improvesignal generation capabilityVSAvoidignition lock size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The magnetic field sensor and magnet configuration replaces bulky conventional electrical switches, significantly reducing the ignition lock's size. The sensor detects rotor position through magnetic field interaction without requiring the space needed for mechanical switch articulation, enabling compact ignition lock design that fits limited vehicle spaces.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If an angle encoder is used as signal generating element, then the ignition lock becomes more compact and cost-effective, but power consumption may increase

Engineering Contradiction:
Improveignition lock simplicityVSAvoidangle encoder power consumption
Core Design Contradiction:
Device complexityVSUse of energy by moving object

Solution Approach 1:

The patent implements dynamic clocking where the angle encoder is activated only during key insertion events rather than continuously. The control unit wakes up the angle encoder from sleep mode when a key is detected, performs the necessary angular position measurements, and then returns it to sleep mode. This periodic operation dramatically reduces power consumption while maintaining full functionality when needed.

Inventive Principle:
Principle #19Periodic action

4Measurement precision

If the angle encoder is operated continuously, then precise angular position detection is available, but quiescent current consumption increases

Engineering Contradiction:
Improveangular position detection precisionVSAvoidquiescent current consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by stationary object

Solution Approach 1:

The angle encoder operates in discrete measurement cycles triggered by key insertion events. During normal vehicle operation with the key in the ignition, the encoder remains in sleep mode with minimal quiescent current. When a key is inserted, the control unit activates the encoder to measure the initial angular position, then deactivates it. This periodic operation maintains precise measurement capability while minimizing energy consumption during stationary periods.

Inventive Principle:
Principle #19Periodic action

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 design results in a compact, cost-effective, and functionally reliable ignition lock with reduced power consumption, easier assembly, and enhanced security, adaptable to various vehicle types with precise signal generation and reduced installation volume.

Implementation Method 1

The signal-generating element consists of an angle encoder, in particular in the form of a rotary angle sensor... The angle encoder can be configured as a magnetic field sensor, in particular in the manner of a Hall sensor

Methodology Applied
Scientific EffectMagnetic field sensing: Magnetic Field

Implementation Method 2

A coil for transmitting energy to the key when the key is in the receptacle is arranged in the ignition lock

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2036790B1Ignition lock for a motor vehicle
Publication Date: 2012.11.07 MARQUARDT GMBH
  • EP2036790B1 patent drawingFigure 1
  • EP2036790B1 patent drawingFigure 2
  • EP2036790B1 patent drawingFigure 3

AI summary

The lock has an operating unit (5) designed as a rotor and movable from a starting position to an operating position. The operating unit acts together with a signal generating element (6) in the operating position for generating electrical system signals for a motor vehicle. The signal generating element has an angle encoder in the form of a rotating angle sensor, an electrical switching element and a sensor element, where the angle encoder is operated by a cam disk that is arranged at the operating unit.