Fuel Injection Valve Coating Edge Rounding

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional fuel injection valve coatings tend to detach at sharp edges, leading to premature wear and reduced service life due to impact and sliding loads, compromising the anti-wear effect.

Innovation Solution

Rounding the transition edges of the coated areas with a radius of 100 μm to 150 μm prevents coating detachment, ensuring the wear-reducing coating adheres reliably to the valve sealing surface, including the annular groove transitions, thereby maintaining its effectiveness throughout the valve's service life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a wear-reducing coating is applied to the valve element surfaces, then the wear resistance and service life are improved, but the coating detaches at sharp edges due to impact and sliding loads

Engineering Contradiction:
Improvecoating adhesionVSAvoidcoating detachment
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies edge rounding with a radius of 100 μm to 150 μm to the transition edges of the coated areas. This curvature eliminates sharp edges that cause stress concentration and coating detachment, allowing the wear-reducing coating to adhere reliably throughout the valve's service life while maintaining its wear protection function

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Productivity

If the valve element is subjected to impact loads during operation, then the valve controls fuel flow effectively, but the coating detaches prematurely reducing service life

Engineering Contradiction:
Improvefuel flow controlVSAvoidservice life
Core Design Contradiction:
ProductivityVSDuration of action of stationary object

Solution Approach 1:

The patent performs edge rounding as a preliminary action before the valve enters service. By pre-rounding the transition edges with a radius of 100 μm to 150 μm, the design anticipates and prevents the coating detachment that would otherwise occur during impact loading, thereby extending the valve's service life while maintaining effective fuel flow control

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP1880101B1Valve, in particular fuel injection valve
Publication Date: 2012.05.16 ROBERT BOSCH GMBH
  • EP1880101B1 patent drawingFigure 1
  • EP1880101B1 patent drawingFigure 2

AI summary

A valve, preferably a fuel injection valve for internal combustion engines, comprises a housing (1) in which is arranged a movable valve element (5) whose surface has at least one section (7; 15) provided with a wear-reducing coating (40). The coated surface section (7; 15) is exposed during operation of the valve to repeated friction or impact stresses, a rounded edge (36; 38; 39) being formed inside and/or at the border of the coated partial surface (7; 15).