High-Pressure Fuel Pump Flange Welding With Splash-Receiving Groove
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Solution Overview
Problem
High-pressure fuel pumps face issues with welding splashes during the welding process, which can damage the pump housing and fixing flange due to the free surface of the weld bead coming into contact with the cold housing wall, leading to suboptimal connections.
Innovation Solution
The implementation of a receiving space wider than the weld bead in the radial direction, specifically an annular space created by a circumferential groove, prevents the weld bead from contacting the cold wall, and an opening connects this space to the environment to manage pressure, while capacitor discharge welding ensures efficient energy concentration within the weld zone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If capacitor discharge welding is used to rapidly join the fixing flange to the pump housing, then welding speed and energy efficiency are improved, but welding splashes are generated that can damage the components
Solution Approach 1:
The pump housing wall is segmented into a first wall portion and a second wall portion, with the weld bead positioned between them. The first wall portion provides support for the weld bead while the second wall portion is protected from splash damage, effectively dividing the wall to isolate the harmful effects of welding splashes from the critical components.
Solution Approach 2:
The first wall portion acts as an intermediary element between the weld bead and the second wall portion. It absorbs and deflects the welding splashes, preventing them from reaching and damaging the second wall portion and other critical components of the pump housing.
2Stability of the object's composition
If the weld bead is allowed to contact the cold housing wall for support, then welding stability is improved, but welding splashes are generated that damage the components
Solution Approach 1:
The housing wall is divided into functional zones: the first wall portion serves as the contact zone for weld bead stability, while the second wall portion remains protected from splash damage. This segmentation allows the weld bead to be supported where needed while isolating critical components from harmful effects.
3Object-affected harmful factors
If a receiving space is created to contain welding splashes, then component protection is improved, but device complexity increases
Solution Approach 1:
The receiving space functionality is merged into the existing housing structure by forming the first and second wall portions as integral parts of the pump housing. This combines the protective function with the structural housing design, avoiding additional complex components while still providing effective splash containment.
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 solution prevents welding splashes and ensures an optimal connection between the pump housing and fixing flange, maintaining component integrity and efficiency through rapid and economical welding, reducing the risk of damage and improving the connection quality.
Implementation Method 1
the energy required for welding is connected to a welding transformer via a thyristor from pre-charged capacitors. Here, the charging times are in a range between 0.5 s and 2 s, and the welding times between 3 and 10 ms. In parallel with this, the effective resistance applied by the welding preparation makes the temperature at the welding location rise at a very rapid rate.
Implementation Method 2
the free surface of the weld bead which emerges at the edge of the weld region from coming into contact with the cold housing wall, e.g. that of the pump housing or of the fixing flange, during the welding process. This in turn prevents the formation of welding splashes
Data Source
AI summary
A high-pressure fuel pump for a fuel injection system of an internal combustion engine includes a pump housing and at least one fastening flange that is fixed to the pump housing by a welding. The welding has one weld region and at least one weld bead arranged laterally from the weld region. The weld bead is arranged in a receiving space formed between the pump housing and the fastening flange.