High-Pressure Fuel Pump Flange Welding With Spatter-Containment Recess

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Solution Overview

Problem

Existing high-pressure fuel pumps face issues during the welding process, where the welding bead can come into contact with the cold housing wall, leading to weld spatter and potential damage to the pump components, and there is a need for an efficient and cost-effective welding method that prevents undesired pressure buildup.

Innovation Solution

The high-pressure fuel pump design incorporates a receiving space wider than the weld bead, an annular space created by a circumferential groove, and an opening to prevent contact with the pump housing, along with capacitor discharge welding to concentrate energy efficiently and prevent heat dissipation, ensuring optimal connection without damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If traditional welding is used to connect the fastening flange to the pump housing, then the connection strength is improved, but weld spatter damages the pump housing and fastening flange

Engineering Contradiction:
Improveconnection strengthVSAvoidweld spatter damage
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The welding area is segmented into a recess that isolates the weld bead from the external environment. This recess creates a protected zone where the welding process occurs, preventing spatter from reaching and damaging the pump housing and fastening flange surfaces.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The recess acts as an intermediary structure between the welding process and the components being protected. It serves as a barrier that contains the harmful welding byproducts while allowing the welding process to proceed effectively.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If capacitor discharge welding is used to reduce welding time and cost, then productivity and economy are improved, but heat concentration may cause localized overheating

Engineering Contradiction:
Improvewelding speedVSAvoidlocalized heat concentration
Core Design Contradiction:
ProductivityVSTemperature

Solution Approach 1:

The recess provides a thermal buffer zone that absorbs and dissipates the concentrated heat from capacitor discharge welding. By positioning the weld bead within this recess, the heat is contained and distributed more effectively, preventing damage to surrounding components while maintaining the high-speed welding process.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Object-affected harmful factors

If the receiving space is made wider than the weld bead, then protection from weld spatter is improved, but the device complexity increases

Engineering Contradiction:
Improveweld spatter preventionVSAvoidstructural complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The recess is integrated into the existing pump housing structure, combining the protective function with the housing design itself. This merging approach adds minimal complexity while effectively preventing weld spatter damage.

Inventive Principle:
Principle #5Merging (Combining)

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 effectively prevents weld spatter and ensures a strong, efficient connection between the pump housing and fastening flange, maintaining component integrity and reducing assembly complexity while maintaining high welding efficiency.

Implementation Method 1

In capacitor discharge welding, the energy required for welding is switched from previously charged capacitors to a welding transformer via a thyristor. The loading times are in the range between 0.5 s and 2 s, the welding times between 3 and 10 ms. At the same time, the effective resistance applied during welding preparation causes the temperature at the welding point to rise at a very high rate.

Methodology Applied
Scientific EffectCapacitor discharge welding: Joule Heating

Implementation Method 2

it is prevented during the welding process that the welding bead emerging at the edge of the welding area comes into contact with its free surface with the cold housing wall, for example the pump housing or the fastening flange. This in turn prevents weld spatter from forming which can damage the pump housing and/or the mounting flange and/or the weld area

Methodology Applied
Scientific EffectThermal shock prevention: Thermal Shock

Data Source

PatentEP3458705B1High-pressure fuel pump
Publication Date: 2021.09.22 ROBERT BOSCH GMBH
  • EP3458705B1 patent drawingFigure 1
  • EP3458705B1 patent drawingFigure 2~4

AI summary

The invention relates to a high-pressure fuel pump (10) for a fuel injection system of an internal combustion engine, comprising a pump housing (12) and at least one fastening flange (32), wherein the fastening flange (32) is fixed to the pump housing (12) by a welding (34), and wherein the welding (34) has one weld region and at least one weld bead (40) arranged laterally from the weld region (34). It is proposed that the weld bead (40) is arranged in a receiving space (46) formed between the pump housing (12) and the fastening flange (32).