Fuel Rail End Cap Structure for High-Pressure Boundary Protection
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Solution Overview
Problem
Conventional gasoline direct injection rails with U-shaped end caps experience excessive load concentration at the boundary between the rail body and end cap due to a large level difference, leading to potential damage under high pressure.
Innovation Solution
The design features a rail body with an inner circumference depression to accommodate the end cap's circumferential wall, eliminating the level difference and ensuring a h/T ratio of 0 < h/T ≤ 0.25, which increases the end cap breaking pressure and prevents load concentration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the circumferential wall of the end cap has a large thickness, then the end cap has sufficient strength, but a large level difference is formed at the boundary part between the rail body and end cap, causing excessive load concentration and potential damage under high pressure
Solution Approach 1:
The invention introduces a depression at the end part of the rail body where the circumferential wall is inserted. This local structural modification allows the thick circumferential wall to be accommodated without creating a large level difference at the boundary, thereby maintaining both end cap strength and boundary part reliability under high pressure conditions
2Reliability
If the circumferential wall thickness is reduced to eliminate level difference, then load concentration is reduced, but the end cap strength is compromised
Solution Approach 1:
Instead of reducing the circumferential wall thickness in the radial direction, the invention creates a depression in the axial direction of the rail body. This dimensional approach allows the thick circumferential wall to be inserted into the depression, eliminating level difference at the boundary while preserving the end cap's strength
Data Source
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AI summary
To obtain a gasoline direct injection rail in which a large load is unlikely to be concentrated on a boundary part between a rail body and an end cap, and damage to the boundary part can be prevented, even when high pressure is applied to the inside of the rail body. The gasoline direct injection rail comprises an end cap 4 composed of a top plate 5 and a circumferential wall 6, and a rail body 1 having an end part 2 in which the circumferential wall 6 of the end cap 4 is inserted and placed, wherein an inner circumference of the end part 2 of the rail body 1 has a depression 3, the circumferential wall 6 is placed in the depression 3, and there is no level difference at a boundary part 12 between an inner circumferential surface 11 of the circumferential wall 6 and an inner circumferential surface 10 of the rail body 1.