Vehicle Alarm Tilt Threshold Control for Engine Vibration

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Solution Overview

Problem

Existing motor vehicle alarm systems with anti-lift functions are overly sensitive to minor vehicle tilts, often triggering false alarms during vehicle preconditioning due to engine vibrations, which is undesirable.

Innovation Solution

A method for controlling the vehicle alarm system by configuring tilt thresholds based on the engine's operating state, adjusting sensitivity levels to prevent false alarms during engine startup, operation, and shutdown phases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the alarm system is configured with a low tilt threshold to detect break-ins, then the sensitivity to intrusion is improved, but false alarms are triggered during engine operation due to vibrations

Engineering Contradiction:
Improvetilt detection sensitivityVSAvoidalarm false triggering
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The alarm system dynamically adjusts the tilt threshold based on engine operating state. When the engine is detected to be running, the system temporarily increases the tilt threshold, making the alarm less sensitive to vibrations caused by engine operation. When the engine is off, the threshold returns to its normal low value for break-in detection. This dynamic adaptation resolves the contradiction by making the sensitivity parameter variable rather than fixed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the threshold parameter according to engine state. A control unit monitors engine operation and modifies the tilt threshold value accordingly - using a first threshold when the engine is off and a second, higher threshold when the engine is running. This parameter change allows the same alarm system to operate reliably under different operating conditions without requiring separate systems.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If the alarm system uses a fixed tilt threshold, then the system complexity is reduced, but the system cannot adapt to different engine operating states

Engineering Contradiction:
Improvealarm control structureVSAvoidresponse to engine states
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The alarm control unit performs multiple functions: it monitors engine operating state, determines whether the engine is running or off, and adjusts the tilt threshold accordingly. This single control unit handles both security monitoring and adaptive threshold adjustment, making the system versatile without adding significant complexity. The control unit essentially serves dual purposes of security management and operational adaptation.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system pre-defines multiple threshold values (first threshold for engine-off state, second threshold for engine-on state) and selects the appropriate one based on current conditions. This preliminary preparation of multiple parameters allows the system to adapt quickly to different engine states without complex real-time calculations, maintaining simplicity while achieving adaptability.

Inventive Principle:
Principle #10Preliminary 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

Prevents unnecessary alarm triggers during vehicle preconditioning by setting tailored tilt thresholds based on engine states, enhancing the reliability and relevance of the alarm system.

Implementation Method 1

a tilt sensor (3) configured to detect a tilt of the motor vehicle (1)

Methodology Applied
Scientific EffectGravitation: Gravitation

Data Source

PatentEP4347324B1Method for controlling an alarm for a motor vehicle
Publication Date: 2026.01.14 STELLANTIS AUTO SAS
  • EP4347324B1 patent drawingFigure 1~2

AI summary

The invention relates to a method for controlling an alarm system (10) for a motor vehicle (1), the control method comprising a configuration step allowing multiple inclination thresholds to be defined according to the state of operation of the motor vehicle (1) and/or according to a temperature of the engine. The control method thus allows the thresholds at which the alarm system (10) and its warning device (4) are triggered to be adjusted according to certain specific phases of the motor vehicle (1), these being associated with its use and more specifically with the state of operation of the engine.