Saddle-Type Vehicle Catalytic Device Layout
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Solution Overview
Problem
Saddle-type vehicles with a single catalyst in the exhaust pipe face challenges in efficiently purifying exhaust gases due to the limited size of the catalytic device, which restricts its ability to accommodate multiple catalysts for enhanced purification.
Innovation Solution
A compact layout for a catalytic device is achieved by positioning multiple catalysts in the exhaust pipe, with the first catalyst disposed upstream and adjacent to the exhaust port, and the second catalyst downstream, allowing for early activation and increased purification efficiency, while the link is positioned above the crankcase to create space for the catalytic device and ensure stable support during engine movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple catalysts are placed in the exhaust pipe to increase purification ability, then the purification efficiency is improved, but the catalytic device size increases
Solution Approach 1:
The catalytic device is oriented with its longitudinal direction in the width direction of the vehicle, and positioned to overlap the fuel tank in front view. This spatial reorientation allows multiple catalysts to be arranged in a compact layout that fits within the limited space below the floor step, achieving enhanced purification efficiency without increasing overall device size
Solution Approach 2:
The catalytic device is disposed below the fuel tank, utilizing the space beneath the fuel tank as a housing location. This nesting arrangement allows the catalytic device with multiple catalysts to be integrated into the existing vehicle structure without occupying additional external space
2Area of stationary object
If the catalytic device is positioned to overlap the fuel tank in front view, then the space utilization is improved, but the risk of heat interference with the fuel tank increases
Solution Approach 1:
A heat insulation plate is disposed between the catalytic device and the fuel tank. This intermediary component blocks heat transfer from the hot catalytic device to the fuel tank, allowing the catalytic device to be positioned in the space below the fuel tank without creating harmful thermal effects on the fuel storage
3Volume of moving object
If the link is disposed upward of the crankcase, then the space for catalytic device is improved, but the structural complexity increases
Solution Approach 1:
The link is configured to allow the unitary swing engine to swing relative to the vehicle body frame, creating dynamic space below the engine that can be utilized by the catalytic device. This dynamic arrangement provides the necessary installation space without requiring permanent structural modifications that would increase complexity
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 compact layout enables early activation of the catalytic device for enhanced exhaust gas purification and stable support during engine movement, improving the vehicle's emission control capabilities without increasing the device's size or interfering with other components.
Implementation Method 1
a catalytic device disposed in the exhaust pipe
Data Source
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AI summary
Disclosed is a saddle-type vehicle incorporating a unitary swing engine 13 having a catalytic device 140 with first and second catalysts 142, 143. A link 38 is disposed upward of a crankcase 34, and part of the catalytic device 140 is disposed downward of an engine cylinder assembly 35. The catalytic device 140 is disposed in an area between a hypothetical line L1 interconnecting a link joint 39 and a front end of the crankcase 34 and a hypothetical line L2 interconnecting an exhaust pipe joint 35e and the link joint 39. The first catalyst 142 disposed upstream in an exhaust pipe 121 is disposed forward of the crankcase 34 and downward of the cylinder assembly 35, and is disposed adjacent to an exhaust port 35c of the unitary swing engine 13 as viewed in bottom view. The first catalyst can be activated early to allow the catalytic device to have an increased ability to purify exhaust gases.