Single-Plate Fuel Rail Design for High Pressure

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Solution Overview

Problem

Existing fuel rails face challenges in achieving high fuel pressure durability, material yield, and cost-effectiveness, particularly at pressures of 50 MPa or more, with conventional methods often resulting in uneven external shapes, low material yield, and increased costs.

Innovation Solution

A fuel rail design featuring a main pipe portion and distribution pipe portions cut and formed from a single-sheet plate, with seamless fuel passage and injector attaching holes configured without joints, using methods like laser cutting or gun drill machining, allowing for high-pressure resistance and improved material utilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If hot forging is used to create an integrated fuel rail, then durability is improved, but material yield decreases and cost increases

Engineering Contradiction:
ImprovedurabilityVSAvoidmaterial yield
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The invention changes the manufacturing method from hot forging to a process involving providing a metal bar, forming bores, and bending. This parameter change in the manufacturing process allows for improved material yield while maintaining the structural integrity needed for durability at high fuel pressures.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The fuel rail is created by bending a base pipe that has been formed with specific bores, allowing the structure to be developed from a simpler starting form. This segmentation of the manufacturing process (forming base pipe separately, then bending and assembling) improves material utilization compared to creating the entire complex shape through hot forging.

Inventive Principle:
Principle #1Segmentation

2Reliability

If hot forging is used to create an integrated fuel rail, then durability is improved, but external shape becomes uneven and cost increases

Engineering Contradiction:
ImprovedurabilityVSAvoidcost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention changes the manufacturing method from hot forging to a process involving providing a metal bar, forming bores, and bending. This parameter change in the manufacturing process reduces costs by using more efficient material utilization and simpler forming operations, while still achieving the required durability through proper material selection and structural design.

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If conventional fuel rail designs are used, then manufacturing is simpler, but fuel pressure resistance below 50 MPa is insufficient

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidfuel pressure resistance
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The invention addresses the strength requirement by specifying that the fuel rail be made from metal with appropriate mechanical properties to withstand 50 MPa or more fuel pressure. The bending process and final structure are designed to ensure sufficient strength while maintaining manufacturing feasibility through a systematic production approach.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3252298B1Fuel rail and method of manufacturing same
Publication Date: 2020.10.28 HITACHI AUTOMOTIVE SYST LTD
  • EP3252298B1 patent drawingFigure 1
  • EP3252298B1 patent drawingFigure 2(a)~2(e)
  • EP3252298B1 patent drawingFigure 3(a)~3(b)

AI summary

An objective of the present invention is to provide a fuel rail that can be used at a high fuel pressure of 50 MPa or more, for example, has good engine mountability, and has improved material yield. The present invention is regarding a fuel rail including a main pipe portion 10 extending in a longitudinal direction and a plurality of distribution pipe portions 20a, 20b, 20c, and 20d branching from the main pipe portion in a cross direction, in a fuel supply system in which a fuel compressed by a fuel pump passes through a fuel passage hole of the fuel rail fixed to an engine trough a bracket or a stay, the fuel is supplied to injectors, and the fuel is injected into the engine, the present invention is to cut and form the main pipe portion 10 and the plurality of distribution pipe portions 20a, 20b, 20c, and 20d from a same single-sheet plate 100, the single-sheet plate being a plane plate or a flat plate having an irregular shape in cross section, and to seamlessly configure a main pipe hole 11, distribution pipe holes 21a, 21b, 21c, and 21d, and injector attaching holes 22a, 22b, 22c, and 22d, without joints.