Eccentric Double Pipe Tail Pipe for Noise Absorption
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Solution Overview
Problem
Conventional tail pipe structures that increase the thickness of noise absorbing material to reduce exhaust noise also increase the outer diameter of the tail pipe, which is undesirable.
Innovation Solution
A double pipe tail pipe design with an external pipe and an internal pipe, where the noise absorbing material is positioned between the pipes with varying thickness in the radial direction, and the internal pipe is eccentrically positioned to maintain a constant outer diameter while maximizing noise absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the thickness of the noise absorbing material is increased to reduce exhaust noise, then the noise reduction effect is improved, but the outer diameter of the tail pipe is increased
Solution Approach 1:
The patent applies local quality by creating non-uniform thickness distribution of the noise absorbing material. The material is thicker at the lower side and thinner at the upper side of the tail pipe, matching the directional pattern of exhaust noise propagation. This localized variation in material properties optimizes noise absorption where most needed while maintaining compact overall dimensions.
Solution Approach 2:
The patent employs asymmetry by positioning the internal pipe eccentrically relative to the external pipe, creating an asymmetric double-pipe structure. This asymmetric configuration results in non-uniform spacing between the pipes, which in turn creates the desired non-uniform thickness distribution of the noise absorbing material without requiring uniform increases in outer diameter.
2Object-generated harmful factors
If the thickness of the noise absorbing material is increased to reduce exhaust noise, then the noise reduction effect is improved, but the volume of the tail pipe is increased
Solution Approach 1:
The patent applies local quality by creating non-uniform thickness distribution of the noise absorbing material. The material is thicker at the lower side and thinner at the upper side of the tail pipe, matching the directional pattern of exhaust noise propagation. This localized variation in material properties optimizes noise absorption where most needed while maintaining compact overall dimensions.
3Object-generated harmful factors
If the noise absorbing material thickness is uniformly increased, then noise absorption is improved, but the structural complexity increases
Solution Approach 1:
The patent employs asymmetry by positioning the internal pipe eccentrically relative to the external pipe, creating an asymmetric double-pipe structure. This asymmetric configuration results in non-uniform spacing between the pipes, which in turn creates the desired non-uniform thickness distribution of the noise absorbing material without requiring uniform increases in outer diameter.
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
Effectively reduces exhaust noise without increasing the outer diameter by ensuring that noise enters the thicker parts of the noise absorbing material, thereby enhancing noise reduction efficiency.
Implementation Method 1
a noise absorbing material (3) is disposed between an outer periphery of the internal pipe (2) provided with through-holes (22), which are formed in a peripheral wall, and an inner periphery of the external pipe (1)
Data Source
Figure 1~2
Figure 3~4
AI summary
A tail pipe that is a double pipe including an external pipe (1) and an internal pipe (2) and in which a noise absorbing material (3) is disposed between an outer periphery of the internal pipe (2) provided with a through-hole (22) formed on a peripheral wall and an inner periphery of the external pipe (1). The internal pipe (2) is eccentrically positioned relative to the external pipe (1) so that the noise absorbing material (3) has a larger thickness on one side in a pipe radial direction and a smaller thickness on the other side.