Valve Assembly Spring-Loaded Pistons Sealing

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Solution Overview

Problem

Existing delivery systems for operating/auxiliary substances in internal combustion engines face challenges in precise metering and minimizing dead volume, leading to inefficiencies in gas suction and potential leaks due to tilting or pressure changes.

Innovation Solution

A delivery device with a valve assembly featuring spring-loaded pistons and flexible sealing lips, connected to a lifting magnet, which reduces dead volume and ensures precise alignment and sealing, allowing for efficient gas suction and leak prevention through plasma-coated components and strategically designed guide geometries.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If spring-loaded pistons with flexible sealing lips are used in the valve assembly, then sealing reliability is improved, but device complexity increases

Engineering Contradiction:
Improvesealing reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs flexible sealing lips made of elastomeric material that conform to the valve seat surface, creating reliable seals through elastic deformation. These flexible membranes adapt to surface irregularities and maintain sealing under varying pressure conditions, resolving the contradiction between sealing reliability and device complexity by using inherently flexible components rather than complex adjustment mechanisms.

Inventive Principle:
Principle #30Flexible shells and thin films

2Measurement precision

If the valve assembly is precisely aligned with reference points, then metering precision is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvemetering precisionVSAvoidease of manufacture
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent incorporates reference points and alignment features directly into the valve assembly and pump housing during manufacturing. These pre-established geometric references enable precise alignment of the valve assembly with the pump components without requiring complex adjustment procedures during assembly or operation, thus achieving high metering precision while maintaining ease of manufacture.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If the roughened area on the valve plate is enclosed by sealing lips, then sealing effectiveness is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improvesealing effectivenessVSAvoidmanufacturing precision
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The flexible sealing lips envelop the roughened area on the valve plate, using elastic deformation to accommodate surface imperfections and manufacturing tolerances. The elastomeric material conforms to the roughened surface topology, creating effective seals without requiring high-precision manufacturing of the underlying valve plate, thus resolving the contradiction between sealing effectiveness and manufacturing precision requirements.

Inventive Principle:
Principle #30Flexible shells and thin films

4Device complexity

If the conveying device operates without a pressure sensor, then device complexity is reduced, but control precision worsens

Engineering Contradiction:
Improvedevice complexityVSAvoidcontrol precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent designs the valve assembly with spring-loaded pistons that automatically respond to pressure differential changes across the valve. The spring force provides a reference pressure that balances against the system pressure, enabling the valve to self-regulate flow based on pressure conditions without requiring external pressure sensors or active control systems, thus achieving acceptable control precision while reducing device complexity.

Inventive Principle:
Principle #25Self-service

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 exact metering and reduced dead volume, allowing for effective gas suction and preventing leaks, even under varying pressures and tilting conditions, thereby enhancing the delivery system's efficiency and reliability.

Implementation Method 1

the pistons each have flexible sealing lips and define an element space that can be actuated by a conveying diaphragm

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

both valves are coated with a special plasma coating designed to prevent the elastomer-coated piston from sticking to the thermoplastic mounting plate

Methodology Applied
Scientific EffectPlasma coating: Plasma

Implementation Method 3

The valve assembly is a component of the conveying device and is arranged directly on an actuator, which in this case is preferably designed as a solenoid

Methodology Applied
Scientific EffectElectromagnetic actuation: Electromagnet

Data Source

PatentEP2909478B1Valve assembly for conveying device
Publication Date: 2020.04.29 ROBERT BOSCH GMBH
  • EP2909478B1 patent drawingFigure 1
  • EP2909478B1 patent drawingFigure 2
  • EP2909478B1 patent drawingFigure 3

AI summary

The invention relates to a valve assembly (22, 76) for a conveying device for metering an operating/auxiliary material into an exhaust gas tract of an internal combustion engine. The valve assembly (22, 76) comprises a valve on the intake side (18) and a valve on the pressure side (32). Both are provided with spring-loaded pistons (84, 94). Both pistons (84, 94) comprise flexible sealing lips (102) and delimit an element chamber (98, 100), through which the operating/auxiliary material is conveyed.