Electromagnetic Valve Throttle Element Impact Noise Reduction

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Solution Overview

Problem

Existing electromagnetically actuated valves in air spring systems of motor vehicles produce audible switching noise due to high impact speed, which becomes more noticeable with the reduction of engine noise from emission control measures like automatic start-stop systems and hybrid drives.

Innovation Solution

Incorporating an elastic radial throttle element between the valve volumes to throttle fluid flow, creating overpressure and negative pressure that decelerates the moving assembly, reducing noise by slowing down the impact speed and minimizing the current required for movement, with a design that provides a higher throttling effect during switching on and reduced effect during switching off.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If damping elements are added to reduce impact speed, then switching noise is reduced, but switching time increases and flow cross section is reduced

Engineering Contradiction:
Improveswitching noiseVSAvoidswitching time
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent introduces a throttle element that creates a pressure difference through fluid dynamic effects. When the armature moves, fluid flows through the throttle element, generating a pressure difference that opposes the motion and reduces impact speed without requiring mechanical damping elements, thus maintaining fast switching times

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The patent changes the physical state of the fluid by creating a pressure difference through the throttle element. This parameter change (pressure differential) generates a braking effect that reduces impact noise while maintaining the speed and flow characteristics necessary for fast switching operation

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If damping elements are added to reduce impact speed, then switching noise is reduced, but flow cross section is reduced

Engineering Contradiction:
Improveswitching noiseVSAvoidflow cross section
Core Design Contradiction:
Object-affected harmful factorsVSArea of stationary object

Solution Approach 1:

The throttle element utilizes fluid flow and pressure differential effects rather than mechanical obstruction. The fluid dynamics approach maintains a larger effective flow cross section compared to solid damping elements, as the pressure difference is generated through flow characteristics rather than physical blockage

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

By changing the pressure parameters of the fluid through the throttle element, the patent achieves noise reduction without physically reducing the flow cross section. The pressure differential creates the braking effect while the geometric flow path remains open, preserving flow capacity

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If throttle element is added to decelerate movable assembly, then noise is reduced, but current required for movement increases

Engineering Contradiction:
ImprovenoiseVSAvoidcurrent required for movement
Core Design Contradiction:
Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The throttle element creates a pressure difference that provides passive hydraulic braking during armature movement. This pneumatic/hydraulic approach reduces the mechanical energy of impact without requiring additional electrical energy, thus minimizing the increase in current requirement while effectively reducing noise

Inventive Principle:
Principle #29Pneumatics and hydraulics

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 reduces noise from the valve operation while maintaining a fast switching time and minimal increase in required current, ensuring the valve is acoustically unobtrusive and suitable for air spring systems in motor vehicles.

Implementation Method 1

the throttle element which is elastic in the radial direction and which is arranged between the first and second volumes in such a way that it throttles a fluid flow between the first and second volumes when the movable assembly moves axially

Methodology Applied
Scientific EffectThrottling: Pressure Drop

Implementation Method 2

an overpressure arises in the volume arranged at the front in the direction of movement, which decelerates the movement in the corresponding direction. In particular, when the magnet armature is surrounded by air, the air is compressed in the corresponding volume

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 3

The armature is moved by energizing a coil that surrounds the valve sleeve

Methodology Applied
Scientific EffectElectromagnetic actuation: Electromagnet

Data Source

PatentEP3312484B1Switching valve with impact absorption
Publication Date: 2020.12.09 RAPA AUTOMOTIVE GMBH & CO KG
  • EP3312484B1 patent drawingFigure 1~1A
  • EP3312484B1 patent drawingFigure 2~2A
  • EP3312484B1 patent drawingFigure 3~4

AI summary

An electrically or electromagnetically actuated valve (1) has a movable assembly with a magnetic armature (7) which is movable along an axis between a first and a second position to open or close the valve (1). The valve (1) further has a valve sleeve (22) in which the magnetic armature (7) is movable between the first and second positions, the magnetic armature (7) defining two volumes (12, 13) on its axial sides within the valve sleeve (22). A radially elastic throttle element (9) is provided, which is arranged between the first volume (12) and the second volume (13) such that, during axial movement of the movable assembly, it throttles the airflow between the first volume (12) and the second volume (13) in order to decelerate the movement of the movable assembly.