Forged Fuel Distributor Spigots for Injector Rotation Constraint

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Solution Overview

Problem

Existing fuel distributors for spark-ignition internal combustion engines face challenges in achieving consistent geometry and functional reliability due to manufacturing tolerances, leading to variations in component sizes and rotational freedom issues.

Innovation Solution

The fuel distributor is made of austenitic stainless steel and forged to create a base body with high-pressure connections, followed by precise post-processing to ensure consistent side heights and edge geometries, reducing rotational freedom and simplifying machining.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional manufacturing methods are used for fuel distributors, then production is simpler, but manufacturing precision and geometry consistency deteriorate due to tolerances

Engineering Contradiction:
Improvegeometry consistencyVSAvoidmanufacturing complexity
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by performing post-forging processing to machine the outer contours and connecting spigots after the forging process. This allows the basic geometry to be established through forging, then refined through machining to achieve consistent side heights and spigot geometries across multiple components, compensating for tolerances accumulated during forging.

Inventive Principle:
Principle #10Preliminary action

2Strength

If forging is used to create the base body, then strength and pressure resistance improve, but manufacturing precision deteriorates due to tolerance variations in connecting spigots

Engineering Contradiction:
Improvepressure resistanceVSAvoidspigot geometry consistency
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The forging process is used first to establish the strong base body structure capable of withstanding high pressures. Subsequently, post-forging machining operations are performed to machine the outer contours and connecting spigots to precise tolerances, thereby achieving both high strength from forging and high precision from machining.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the manufacturing parameters by transitioning from a single-process approach to a multi-process approach. The material state is changed from forged (high strength, lower precision) to machined (high precision, maintained strength), achieving both desired properties through parameter changes in the manufacturing process.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If connecting spigots are made with variable geometries due to tolerances, then ease of manufacture improves, but device complexity increases due to rotational freedom issues

Engineering Contradiction:
Improveproduction flexibilityVSAvoidrotational constraint requirements
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The post-forging processing is performed as a preliminary action to machine the connecting spigots to consistent geometries before assembly. This ensures that the side surfaces of the spigots have uniform heights, which naturally restricts rotational freedom and simplifies the assembly process without requiring additional complexity in the design or manufacturing of other components.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4182552B1Component for an injection system, and injection system for mixture-compressing, applied-ignition internal combustion engines, and method for producing a component of this type
Publication Date: 2026.03.11 ROBERT BOSCH GMBH
  • EP4182552B1 patent drawingFigure 1
  • EP4182552B1 patent drawingFigure 2
  • EP4182552B1 patent drawingFigure 3~4

AI summary

The invention relates to a component (3), in particular fluid distributor (2), for an injection system (1) for mixture-compressing, applied-ignition internal combustion engines which apportions a fluid which is under high pressure, having a main part (14) and at least one connection piece (16A-19A) formed on the main part (14) which connects an injection valve (7-10), wherein the injection valve (7-10) can be inserted into a receiving chamber (27-30) of the connection piece (16A-19A) along an assembly axis (40-43) during assembly, wherein at least the main part (14) and the connection piece (46-49) are formed by single or multi-stage forging and wherein a recess (51, 51') is formed on an outside (52, 52') of the connection piece (46-49), into which, in an assembled state, an orientation element (50) of the injection valve (7-10) engages in order to restrict a degree of freedom of rotation of the injection valve (7-10) about the assembly axis (40-43). According to the invention, the connection piece (16A-19A) is reworked after forging such that at least one lateral face (56, 57, 56', 57') of the recess (51, 51') of the connection piece (16A-19A) on which, in the assembled state, in order to restrict a degree of freedom of rotation in a selected rotation direction (49) about the assembly axis (40-43), a contact between the orientation element (50) of the injection valve (7-10) and the connection piece (16-19A) is enabled, is designed at least approximately having a specified side height (58). Furthermore, the invention relates to an injection system having such a component (3) and to a method for producing such a component (3).