EGR Valve Support Structure at Cylinder Head Cover Intersections
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Solution Overview
Problem
The EGR valve in conventional engines is supported with fixing hardware in a cantilever manner, leading to low stiffness and vibration, which deteriorates control accuracy.
Innovation Solution
The EGR device is configured with the EGR valve fastened to first and second fastening portions at high-stiffness intersections and points on the cylinder head cover, enhancing support stiffness and preventing vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the EGR valve is supported with fixing hardware in a cantilever manner, then the device complexity is reduced, but the stiffness in support is low causing vibration and control accuracy deterioration
Solution Approach 1:
The support structure is segmented into multiple fastening portions (first fastening portion at the intersection and second fastening portion on the exhaust side wall) instead of a single cantilever support, distributing the load and increasing overall stiffness
Solution Approach 2:
The support configuration transitions from a one-dimensional cantilever arrangement to a two-dimensional distributed fastening system across different locations on the cylinder head cover, adding spatial dimension to the support structure
2Ease of manufacture
If the EGR valve is supported with fixing hardware in a cantilever manner, then the installation is simplified, but vibration occurs due to low stiffness
Solution Approach 1:
The support structure is divided into multiple discrete fastening portions located at different positions on the cylinder head cover, allowing vibration isolation through spatial distribution while maintaining installation simplicity
Solution Approach 2:
The multiple fastening portions act as counterbalancing support points that distribute and counteract vibrational forces, preventing the EGR valve from vibrating during engine operation
3Strength
If the EGR valve is fastened to multiple fastening portions at high-stiffness intersections, then the stiffness in support is enhanced, but the device complexity increases
Solution Approach 1:
The fastening portions are strategically located at high-stiffness intersections and structurally optimal positions on the cylinder head cover, concentrating support strength at critical locations rather than uniformly distributing fastening elements
Data Source
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AI summary
[Problem to be Solved] It is to provide an EGR device for an internal combustion engine capable of enhancing stiffness in support of an EGR valve on a cylinder head cover to prevent the EGR valve from vibrating to thereby prevent control accuracy of the EGR valve from deteriorating. [Solution] An EGR device 11 for an engine 1 includes: an upstream-side EGR piping 12, an EGR cooler 13, an EGR housing passage portion 26, and a downstream-side EGR piping 15 those of which branch from an exhaust cleaning device 9 and circulate, as an EGR gas, a part of an exhaust gas in the exhaust cleaning device 9 into an intake manifold 8; and an EGR valve 14 to adjust a flow rate at which the EGR gas flows through the EGR housing passage portion 26. The EGR valve 14 is fastened to a first fastening portion 27A that is provided at an intersection 29 where a front wall 25A and a left side wall 25C of an EGR housing portion 25 intersect and a second fastening portion 27B that is provided at the front wall 25A.