Muffler-Mounted Exhaust Sensor Attachment for Distant Catalyst Pipes
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Solution Overview
Problem
Existing methods for attaching an exhaust gas sensor to a muffler are challenging when the catalyst downstream pipe is far apart from the muffler, requiring deep recesses that are difficult to form and costly to manufacture, especially when the distance between the muffler and pipe is long.
Innovation Solution
An attachment member is used to attach the exhaust gas sensor to the muffler, which is separate from the muffler and can be easily manufactured to have the necessary depth and strength, allowing the sensor element to be inserted into the pipe while the cable is outside the muffler.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a recess is formed in the outer wall of the muffler to attach the exhaust gas sensor when the catalyst downstream pipe is far apart from the muffler, then the sensor element can be disposed inside the pipe, but the recess becomes excessively deep and difficult to manufacture
Solution Approach 1:
The attachment structure is divided into two separate components: the muffler body and a protrusion member that attaches to the muffler's outer wall. This segmentation allows the protrusion member to provide the necessary depth for sensor insertion without requiring a deep recess in the muffler itself, thereby simplifying the manufacturing process while maintaining precise sensor positioning.
Solution Approach 2:
A protrusion member serves as an intermediary component between the muffler's outer wall and the exhaust gas sensor. This mediator provides the required depth and structural support for sensor attachment without necessitating a deep recess in the muffler, thus resolving the manufacturing difficulty while achieving accurate sensor element placement inside the catalyst downstream pipe.
2Length of moving object
If the distance between the muffler outer wall and catalyst downstream pipe is long, then the sensor element can reach inside the pipe, but the recess depth required becomes excessive
Solution Approach 1:
The attachment system is segmented into the muffler body and a separate protrusion member. The protrusion member extends from the muffler's outer wall toward the catalyst downstream pipe, providing the necessary reach for the sensor element without requiring an excessively deep recess in the muffler structure.
Solution Approach 2:
Instead of increasing recess depth in the radial direction (which creates manufacturing difficulties), the solution extends the attachment structure in the axial direction using a protrusion member that projects from the muffler's outer wall, thereby achieving the required sensor reach without excessive recess depth.
3Adaptability or versatility
If a deep recess is formed in the muffler outer wall, then the sensor can be attached when the pipe is far apart, but the manufacturing cost increases
Solution Approach 1:
The attachment functionality is segmented into a separate protrusion member that attaches to the muffler's outer wall. This allows the muffler itself to maintain a simple, cost-effective structure without deep recesses, while the protrusion member provides the necessary adaptability for sensor attachment when the catalyst downstream pipe is positioned far from the muffler.
Solution Approach 2:
The protrusion member acts as an intermediary that bridges the gap between the muffler and the exhaust gas sensor. It provides the required attachment depth and structural support without necessitating expensive deep recess formation in the muffler, thereby maintaining manufacturing cost-effectiveness while achieving versatile sensor attachment capability.
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 solution enables easy and cost-effective attachment of the exhaust gas sensor even when the catalyst downstream pipe is far apart from the muffler, ensuring the sensor element is inside the pipe and the cable is outside, without the need for complex manufacturing processes.
Implementation Method 1
When one side of the sensor element formed of zirconia is exposed to exhaust gas and a reference gas (for example, air) is supplied to the other side of the sensor element, an electromotive force is generated in the sensor element due to an oxygen concentration difference between the reference gas and the exhaust gas
Data Source
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AI summary
An exhaust device (15) includes a muffler (17) configured to reduce exhaust noise, a catalyst (62) configured to purify exhaust gas, a pipe in which exhaust gas flows, an exhaust gas sensor (63) configured to detect a state of the exhaust gas, and an attachment member (71) configured to attach the exhaust gas sensor (63) to the muffler (17). The pipe (35) has a sensor insertion hole (38, 92). The attachment member (71) is attached to a peripheral edge portion of a through hole. The attachment member (71) has a bottom hole (74). The exhaust gas sensor (63) is disposed inside the attachment member (71) via the through hole, and is fixed to the attachment member (71) in a state where the one end portion of the exhaust gas sensor (63) is inserted into the bottom hole (74) and into the sensor insertion hole (38, 92).