Double-Wall Muffler Sensor Port Seal for Thermal Wall Movement
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Solution Overview
Problem
The existing design of double-walled engine exhaust mufflers faces challenges due to significant temperature differences between the inner and outer walls, leading to dimensional shifts that require large openings for sensor access, which exposes the muffler to dirt and debris, increasing the risk of fires, especially in environments with high dirt or debris particles.
Innovation Solution
A sealing assembly comprising thin steel plates and washer-type elements with overlapping openings and a tube portion that allows lateral movement, effectively sealing the sensor port while accommodating radial and lateral movements of the boss, preventing dirt and debris ingress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a large opening is provided in the outer wall to accommodate dimensional shifts, then the sensor can be accessed despite temperature-induced movements, but dirt and debris can enter the muffler increasing fire hazard
Solution Approach 1:
The patent employs a flexible diaphragm made of elastic material that seals the opening in the outer wall. This diaphragm can deform laterally to accommodate the dimensional shifts between inner and outer walls caused by temperature differences, while maintaining a sealed closure that prevents dirt and debris from entering the muffler
Solution Approach 2:
The sealing solution transitions from a static seal to a dynamic one where the diaphragm can move laterally in response to the relative movements between walls. This dynamic sealing mechanism adapts to the changing dimensions while maintaining the sealing function throughout the operational temperature range
2Temperature
If the gap between walls is filled with insulation material, then temperature difference between walls is increased for thermal insulation, but dimensional shifts between walls are amplified requiring larger openings
Solution Approach 1:
The flexible diaphragm seal accommodates the amplified dimensional shifts that result from using insulation material between the walls. By providing a dynamic sealing solution that can deform, the system maintains both the thermal insulation benefits and the ability to access sensors without requiring excessively large openings
3Object-affected harmful factors
If the opening in the outer wall is made smaller to prevent dirt ingress, then fire hazard is reduced, but the sensor cannot be accessed due to relative wall movement
Solution Approach 1:
The flexible diaphragm enables the opening to be kept small for safety while still allowing sensor access. The diaphragm can deform laterally to create a passage for the sensor through the boss, maintaining both security against dirt ingress and accessibility for sensor operation
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 sealing assembly maintains the sealing function despite temperature-induced dimensional shifts, preventing dirt and debris from entering the muffler and reducing the risk of fires, while ensuring sensor accessibility in large agricultural machines.
Implementation Method 1
a double-walled shell formed of an inner wall and an outer wall, preferably with a thermal insulation material between the two, in order to limit the temperature of the muffler's outer surface and/or to raise the temperature inside
Implementation Method 2
an important temperature difference appears between the inner and outer walls of the muffler, once the muffler reaches an operational temperature. As a consequence of this, the inner and outer wall undergo important dimensional shifts with respect to each other
Data Source
AI summary
A sealing assembly for a sensor port of a double-walled muffler. The assembly includes at least an outer plate and a washer-type element. The washer-type element has a planar portion provided with an aperture, and a tube portion protrudes from an edge of the aperture. The assembly is mounted on a sensor port provided with a boss fixed to an inner wall of the double muffler wall, and with an opening in an outer wall surrounding the boss. The tube portion is fitted over the boss, and the assembly is fixed to the outer wall. Any radial or lateral movement of the boss relative to the outer wall is able to take place without losing sealing function, due to lateral freedom of movement of the washer-type element relative to the outer plate, and due to the fact that the boss is able to move relative to the tube portion.