Exhaust Silencer Pipe Aperture Placement
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Solution Overview
Problem
Existing exhaust silencer devices fail to effectively prevent condensed water from flowing into the exhaust pipe, leading to plugging, due to inadequate positioning of apertures on the peripheral surfaces of pipes and lack of consideration for rolled-up pipe structures.
Innovation Solution
The exhaust silencer device features inlet and outlet pipes with openings only in the upper half of their peripheral surfaces, sealed in the lower half, and formed as rolled-up pipes with non-joined portions acting as openings, supported by a separator within the expansion chamber to increase protrusion and reduce fluid leakage, and includes larger apertures on the outlet pipe to minimize pressure loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If apertures are formed in the peripheral surfaces of inlet and outlet pipes to allow exhaust gas flow, then exhaust gas can pass through the pipes, but condensed water can easily flow into the exhaust pipe through these apertures when the muffler inclines
Solution Approach 1:
The patent applies local quality by forming apertures only in the upper half area of the inlet and outlet pipes, while keeping the lower half sealed. This creates different functional zones: the upper half allows exhaust gas passage through apertures, while the lower half prevents condensed water entry. This resolves the contradiction by providing localized functionality rather than uniform aperture distribution throughout the pipe perimeter.
2Reliability
If multiple small apertures are formed in the side walls of pipes to suppress condensed water flow, then some water suppression is achieved, but the positions of apertures are not optimized and water can still easily enter when apertures are at low positions
Solution Approach 1:
The patent applies asymmetry by creating an asymmetric aperture distribution pattern where all apertures are concentrated in the upper half area of the pipes, while the lower half remains completely sealed. This asymmetric configuration optimizes the balance between allowing exhaust gas flow and preventing condensed water entry, resolving the contradiction by establishing a clear spatial distinction rather than uniform or random aperture placement.
3Ease of manufacture
If rolled-up pipes are used to reduce manufacturing cost, then production cost decreases, but rolling overlapped portions create additional openings that may allow fluid leakage
Solution Approach 1:
The patent applies local quality by strategically positioning the rolling overlapped portion entirely within the upper half area of the pipe, where it functions as an additional aperture for exhaust gas passage. The lower half remains sealed to prevent condensed water entry. This resolves the contradiction by converting the potential weakness of the rolling overlapped portion into a functional feature that contributes to exhaust gas flow while maintaining water prevention capabilities.
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 configuration effectively prevents condensed water from entering the exhaust pipe, reducing the risk of plugging and pressure loss, while maintaining cost-effectiveness by using rolled-up pipes and optimizing aperture placement.
Implementation Method 1
When the vehicle stops on a slope with the condensed water accumulated and the muffler is inclined, the condensed water sometimes flows into the exhaust pipe
Implementation Method 2
the condensed water within a sub-muffler encounters difficulty reaching the apertures, and leakage of water through the openings is also prevented effectively
Data Source
AI summary
An exhaust silencer device which is interposed in an exhaust passage in a vehicle to reduce exhaust noise comprises a sub-muffler which is interposed in the exhaust passage and has an expansion chamber formed therein; an inlet pipe which is airtightly inserted through an inlet opening of the sub-muffler; and an outlet pipe which is airtightly inserted through an outlet opening of the sub-muffler, wherein the inlet pipe and the outlet pipe are formed with openings (small apertures, non-joined portions) only in their upper half area and their lower half area is sealed without having the openings.