Control Valve Compensation Edge for Stable Fuel Injection

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Solution Overview

Problem

Fuel injection systems in internal combustion engines face instability in fuel injection quantity due to wear and smoothing of cone pairs in switching valves, leading to changes in opening behavior and undesirable drift over the service life.

Innovation Solution

A pressure-balanced switching valve design with a compensation edge on the valve closing body, arranged in front of the sealing seat, forms a throttle gap through operational wear, reducing the effective seat diameter shift and maintaining stable opening behavior by creating a flow-favorable gap that counters pressure variations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a sealing seat is realized with a cone pairing of different cone angles, then the valve can achieve sealing function, but the two cones adapt over time due to wear and smoothing causing the sealing seat to shift and changing the opening behavior

Engineering Contradiction:
Improvesealing functionVSAvoidopening behavior stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies preliminary action by pre-forming a throttle gap in front of the sealing seat that will progressively open up during operation through controlled wear. This preliminary structural feature ensures that as the cone pairing wears and the sealing seat shifts, the throttle gap compensates by reducing pressure on the sealing seat, thereby maintaining stable opening behavior throughout the valve's service life

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent utilizes parameter changes by designing the throttle gap to change its effective size over time through operational wear. The gap transitions from a closed or minimal state when new to a progressively larger state as wear occurs, allowing the pressure reduction effect to increase over time and counteract the sealing seat shift caused by cone adaptation

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If the compensation edge is designed to form a throttle gap through wear, then pressure at the sealing seat is reduced stabilizing opening behavior, but material is removed through abrasion and smoothing

Engineering Contradiction:
Improveopening behavior stabilityVSAvoidmaterial thickness
Core Design Contradiction:
Stability of the object's compositionVSLoss of substance

Solution Approach 1:

The patent applies the blessing in disguise principle by converting the harmful effect of wear and material loss into a beneficial function. The throttle gap is intentionally designed to form through operational wear, transforming the inevitable material removal into a pressure-reducing mechanism that stabilizes opening behavior. The wear that would normally be considered degradation becomes the activation mechanism for the compensation function

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

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 stabilizes the opening behavior of the switching valve over its service life by reducing the range of seat diameter variation and maintaining consistent fuel injection quantity, while the throttle gap formed by wear acts as a pressure reducer, ensuring minimal drift and improved dynamics.

Implementation Method 1

there is a reduction in the pressure applied to the sealing seat

Methodology Applied
Scientific EffectPressure reduction: Pressure Drop

Implementation Method 2

wear due to abrasion and smoothing of the surfaces (geometric adjustment)

Methodology Applied
Scientific EffectAbrasion: Abrasion

Implementation Method 3

operational wear between the valve closing body and the valve seat surface of the valve piece

Methodology Applied
Scientific EffectWear: Wear

Data Source

PatentEP2438287B1Control valve
Publication Date: 2013.06.19 ROBERT BOSCH GMBH
  • EP2438287B1 patent drawingFigure 1~2

AI summary

The invention relates to a control valve (1), which is used in particular as a pressure-compensated valve for fuel injection valves of air-compressing, self-igniting internal combustion engines, comprising a valve piece (2) on which a valve seat surface (8) is configured and a valve closure body (3) that interacts with the valve seat surface (8) to form a seal seat. The valve closure body (3) comprises a compensation edge (21). The compensation edge (21) is located outside of a region (22) for the seal seat.