Catalyst Device Layout in Saddle-Type Vehicle Swing Engine
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Solution Overview
Problem
In saddle riding vehicles, the presence of a link member obstructs the layout of a catalyst device, limiting its compactness and stability, especially when the exhaust device and catalyst device swing together with the unit swing engine.
Innovation Solution
The catalyst device is positioned below the cylinder section, between imaginary lines connecting the link member coupling section and the exhaust pipe connection section, with an exhaust device coupling section that includes a crankcase-side stay and an exhaust-device-side stay, offset and overlapped for enhanced support and compactness, allowing the catalyst device to be securely held without additional holders or packings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the catalyst device is disposed in a conventional position, then it can be installed, but the link member becomes an obstacle and the layout freedom is limited
Solution Approach 1:
The catalyst device is repositioned from conventional lateral placement to a lower position beneath the cylinder section, utilizing the vertical dimension and the space between the crankcase and exhaust pipe connection. This dimensional shift allows the catalyst device to bypass the link member obstacle and achieve compact integration without interfering with the swing mechanism.
2Volume of moving object
If the catalyst device is disposed compactly, then it saves space, but it may collide with peripheral parts when swung with the unit swing engine
Solution Approach 1:
The catalyst device is nested within the exhaust system structure, specifically positioned within the region bounded by the exhaust pipe connection section and the crankcase. This nesting approach allows the catalyst device to occupy unused space while being structurally integrated into the exhaust system, ensuring it moves as a unified assembly without colliding with peripheral parts.
3Device complexity
If the exhaust device and catalyst device are swung together with the unit swing engine, then the structure is simplified, but the catalyst device needs stable support against swinging
Solution Approach 1:
The exhaust device coupling section merges the support functions for both the exhaust device and catalyst device into a single integrated structure. By positioning the catalyst device within the coupling section's supported region and using the same coupling mechanism to support both components, the system achieves structural simplicity while maintaining stability through unified support against swinging motions.
Data Source
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AI summary
A saddle riding vehicle includes a unit swing engine 13 swingably supported on a body frame 12 through a link member 38, and an exhaust device 120 provided with an exhaust pipe 121 and a catalyst device 140. The link member 38 is disposed on an upper side of a crankcase 34. Part of the catalyst device 140 is disposed below a cylinder section 35 and is located in a region between an imaginary line L1 that connects a link member coupling section 61 coupling the link member 38 to the body frame 12 and a front end of the crankcase 34 and an imaginary line L2 that connects an exhaust pipe connection section 35e of the unit swing engine 13 connected with an end of the exhaust pipe 121 and the link member coupling section 61, in side view. An exhaust device coupling section 135 that couples the crankcase 34 and the exhaust device 120 is provided. The degree of freedom in laying out the catalyst device can be enhanced, the catalyst device can be disposed in a compact fashion, and the catalyst device can be supported stably and firmly even if the exhaust device and the catalyst device are swung together with the unit swing engine.