Saddle Vehicle Catalyst Positioning for Occupant Safety
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Solution Overview
Problem
In conventional saddle riding vehicles, catalysts are positioned close to occupants, making it difficult to ensure safe separation and compact installation due to overlapping with main frames, which complicates exhaust system assembly.
Innovation Solution
The catalyst is positioned in the muffler, surrounded by the main frame, seat frame, and rear frame, overlapping with the air cleaner box, allowing for separate and compact placement, with additional features like a concave portion in the air cleaner box and curving outer wall portions to optimize space usage and airflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the catalyst is disposed in the exhaust pipe overlapping with the main frames as viewed in side view, then the exhaust system structure is simplified, but the catalyst becomes close to the occupant's legs and safety is compromised
Solution Approach 1:
The patent transitions the catalyst placement from a two-dimensional arrangement (overlapping main frames in side view) to a three-dimensional arrangement (overlapping air cleaner box in plan view). This dimensional shift allows the catalyst to be positioned in the space between the exhaust pipe and air cleaner box, achieving both structural simplicity and occupant safety by moving the hot catalyst away from the occupant's legs while maintaining exhaust system integration
2Object-affected harmful factors
If the catalyst is disposed separately from the occupant, then safety is improved, but the space required for catalyst installation increases and compactness is reduced
Solution Approach 1:
The patent merges the catalyst placement with the air cleaner box positioning. By placing the catalyst in the space overlapping the air cleaner box (in plan view), the design utilizes existing structural space rather than adding separate installation volume. This merging approach allows the catalyst to be disposed separately from the occupant for safety while maintaining compact overall vehicle dimensions
Solution Approach 2:
The catalyst is nested within the spatial envelope defined by the exhaust pipe and air cleaner box arrangement. The catalyst fits into the available space between these components, effectively nesting it within the existing structural framework without requiring additional external space, thus achieving compact installation while maintaining safety separation
3Volume of moving object
If the catalyst is disposed in the space overlapping the air cleaner box, then compact installation is achieved and occupant safety is ensured, but the exhaust system assembly complexity increases
Solution Approach 1:
The patent performs preliminary positioning of the exhaust pipe relative to the air cleaner box before final catalyst installation. By pre-establishing the spatial relationship between the exhaust pipe and air cleaner box, the catalyst can be directly placed in the predetermined overlapping space without requiring complex real-time alignment during assembly, thus reducing overall assembly complexity while maintaining compact placement
Data Source
AI summary
A saddle riding vehicle includes a body frame, an exhaust pipe, a muffler, and a catalyst. The body frame includes a main frame, a seat frame that extends rearward from the main frame and supports a seat for occupant, and a rear frame that extends from the main frame upward to a rear and is connected to the seat frame. The exhaust pipe extends rearward of the vehicle from an exhaust port of an engine. The muffler is connected to a rear end portion of the exhaust pipe. The catalyst is disposed in the muffler. An air cleaner box is disposed rearward of the engine. The catalyst disposed in the muffler is disposed in a space surrounded by the main frame, the seat frame, and the rear frame and overlaps with the air cleaner box as viewed in a side view of the vehicle.