EGR Recirculation Pipe Bellows Layout for Resonance Avoidance
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Solution Overview
Problem
Recirculation pipes in exhaust gas recirculation systems are prone to destruction due to resonance caused by vibration frequencies matching those of the engine and vehicle, leading to structural failures.
Innovation Solution
The recirculation pipe design incorporates multiple bellows tube assemblies with varying pitches and numbers of bellows tubes, allowing for the adjustment of natural frequencies to avoid overlap with engine and vehicle vibration frequencies, thereby preventing resonance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the recirculation pipe uses a conventional rigid structure, then it provides structural strength, but it is prone to resonance and destruction when natural frequency matches engine or vehicle vibration frequency
Solution Approach 1:
The patent changes the physical parameters of the recirculation pipe by incorporating bellows tube assemblies with specific pitch values and numbers. This modifies the natural frequency of the pipe structure to avoid resonance with engine and vehicle vibration frequencies, thereby improving reliability without sacrificing structural strength
Solution Approach 2:
The recirculation pipe is segmented into multiple sections with different bellows tube assemblies. Each assembly has different pitch and number of bellows tubes, creating a composite structure that reduces overall resonance susceptibility while maintaining local structural integrity
2Reliability
If the recirculation pipe is made more flexible to reduce resonance, then resistance to vibration improves, but structural strength may be compromised
Solution Approach 1:
The pipe is divided into multiple segments with bellows tube assemblies that provide flexibility for vibration resistance while the overall segmented structure maintains structural strength through distributed reinforcement
Solution Approach 2:
The recirculation pipe uses a composite structure combining rigid pipe body sections with flexible bellows tube assemblies. This composite design allows different parts to fulfill different functions - rigid sections provide strength while bellows sections provide vibration resistance
3Reliability
If additional structures are added to reduce resonance, then vibration resistance improves, but device complexity and mass increase
Solution Approach 1:
The bellows tube assemblies serve multiple functions: they provide vibration resistance through their flexible structure, maintain structural integrity as part of the pipe body, and enable exhaust gas recirculation flow. This multi-functionality reduces the need for additional separate vibration-damping components
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 design effectively reduces the natural frequency of the recirculation pipe by up to 30% compared to conventional designs, enhancing its durability and preventing damage from resonance without increasing mass or adding additional structures.
Implementation Method 1
if the natural frequency of the recirculation pipe coincides with the vibration frequency generated during driving of the vehicle or the vibration frequency generated by the engine, resonance occurs in the recirculation pipe
Implementation Method 2
the recirculation pipe connected to the EGR cooler is destroyed by vibration generated by the running of the vehicle running, or vibration generated in the engine
Data Source
AI summary
A recirculation pipe and an engine system including the same are provided. A recirculation pipe of an EGR apparatus may include a pipe body, and a plurality of bellows tube assemblies formed in the pipe body and including a plurality of bellows tube. One bellows tube assembly among the plurality of bellows tube assemblies and another bellows tube assembly among the plurality of bellows tube assemblies have different shapes.