Exhaust-Gas Conduction Component Vibration Decoupling
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Solution Overview
Problem
Exhaust-gas conduction components in motor-vehicle systems face service life issues due to fatigue fractures and wear at contact points between pipes and decoupling elements, leading to vibration decoupling inefficiencies and heat loss.
Innovation Solution
A vibration-decoupling exhaust-gas conduction component with a smooth middle section and two corrugated pipe sections, connected via a peripheral joint, featuring an annular air gap to reduce friction and heat transfer, and designed to absorb oscillation energy effectively, with a resonance frequency above typical engine vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inner pipe and outer pipe are connected rigidly by a peripheral joint in the middle section, then vibration decoupling is improved and service life is extended, but heat transfer between pipes is reduced which may affect thermal efficiency
Solution Approach 1:
The exhaust-gas conduction component is divided into multiple sections: end sections with smooth construction for rigid connection, a middle section with smooth construction for rigid peripheral joint connection between inner and outer pipes, and first and second corrugated pipe sections for vibration decoupling. This segmentation allows each section to perform its specific function optimally while working together as an integrated system.
2Stability of the object's composition
If corrugated pipe sections are used for vibration decoupling, then vibration absorption is improved, but fatigue fractures and wear at contact points occur reducing service life
Solution Approach 1:
Different sections of the component have different construction qualities: the end sections and middle section have smooth construction for rigid connection and structural stability, while the first and second corrugated pipe sections have corrugated construction for vibration decoupling. The rigid peripheral joint in the middle section provides localized structural reinforcement at the critical connection point between inner and outer pipes, preventing fatigue fractures while maintaining vibration absorption capabilities in the corrugated sections.
3Stability of the object's composition
If the component is designed with symmetric construction and two corrugated pipe sections, then natural vibration response is improved and resonance frequency is increased, but manufacturing complexity increases
Solution Approach 1:
While the overall component has a symmetric appearance with two corrugated pipe sections, the internal structure and connection details may have asymmetric features optimized for manufacturing. The symmetric external design achieves the desired vibration response characteristics, while the manufacturing process can exploit the symmetry to reduce complexity through repeated patterns and standardized production techniques.
4Reliability
If the annular air gap is maintained across the entire component length, then friction wear is avoided and service life is extended, but thermal isolation is improved which may affect heat management
Solution Approach 1:
The component is segmented into regions with different thermal management requirements: the end sections allow for thermal connection to external components, the middle section with rigid peripheral joint maintains the air gap for thermal isolation at the critical connection point, and the corrugated pipe sections maintain the air gap for vibration decoupling while preventing friction wear. This segmentation allows optimization of both wear resistance and thermal management in different regions.
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
The design enhances service life by minimizing mechanical stress and heat loss, improving vibration decoupling and thermal isolation, while allowing for axial movement and curvature, effectively damping engine vibrations and extending component lifespan.
Implementation Method 1
Due to the annular air gap present at least approximately across the entire component length between the inner pipe and outer pipe, rubbing of the inner pipe and the outer pipe and thus friction wear are avoided. Due to the typically small mechanical attachment surface of the inner pipe on the rigid middle section of the outer pipe by the joint, a mutual vibration stimulation is low. Nevertheless, the mass contribution of the inner pipe favorably influences the natural vibration response of the entire component. Furthermore, due to the low, advantageously annular contact surface between the inner pipe and outer pipe, thermal transfer is reduced and thus the isolation behavior of the exhaust-gas conduction component is further improved.
Implementation Method 2
The corrugated pipe sections have approximately the same length and the same natural vibration response and act similarly as expansion equalizers and vibration decouplers. Each of the two corrugated pipe sections connected to each other by the rigid middle section is designed, in particular, with a short construction, so that its resonance frequency lies above the typical vibration excitation from the internal combustion engine. On the other hand, it is possible to construct the exhaust-gas conduction component overall, in particular, to design it with a low frequency with respect to its natural frequency behavior so that incoming oscillation energy is effectively absorbed.
Implementation Method 3
the inner pipe is constructed as an elastic metal pipe that is flexible in the longitudinal direction and that is rigidly connected to the outer pipe by a peripheral joint in the end region of the end sections at least in some points and is arranged free from contact with the outer pipe with the exception of the connections to the outer pipe provided at the joints. Due to the elastic construction of the inner pipe flexible in the longitudinal direction, this pipe can follow vibrational expansions of the outer pipe and stresses between the inner pipe and outer pipe are avoided.
Data Source
AI summary
An exhaust-gas conduction component that is effective as a vibration decoupling element and can be installed in an exhaust-gas system for conducting the exhaust gases of a motor vehicle internal combustion engine. The exhaust-gas conduction component (1) has an outer pipe (2) with a corrugated metal tube section (3; 4) and an inner pipe (8) that is coaxial with the outer pipe (2) and separated from the latter by an annular gap. The outer pipe (2) also has a smooth central section (5), first and second corrugated metal tube sections (3; 4) and smooth first and second end sections (6; 7). The inner pipe (8) is permanently fixed to the outer pipe (2) by a continuous joint (9) extending around the central section (5) and the rectilinear exhaust-gas conduction component (1) is approximately axially symmetrical in relation to a central transverse axis (10). The exhaust-gas conduction component is especially suitable in utility vehicles for linking an emission control unit to an internal combustion engine.