Air Cleaner Case Positioning for Straddled Vehicle
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Solution Overview
Problem
The existing design of air cleaners in straddled vehicles, such as motorcycles with V-type engines, results in a large size that increases the likelihood of the rider's leg coming into contact with the air cleaner when sitting on the seat and placing a foot on the footrest, due to the air cleaner's lateral arrangement and shared capacity for both engine cylinders.
Innovation Solution
The air cleaner case is positioned to overlap with the V-type engine in a vehicle side view, with side cowls protecting vehicle components and dividing the air cleaner case into clean and dirty side chambers, allowing for sufficient capacity without increasing size, and the dirty side chamber is integrated into the side cowl space to position the air cleaner further forward and upward, reducing the risk of leg contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the air cleaner box is arranged laterally to the V-type engine to ensure sufficient capacity for both cylinders, then the clean side chamber and dirty side chamber capacity is improved, but the air cleaner size increases in width, top-and-bottom direction, and front-and-rear direction
Solution Approach 1:
The patent repositions the air cleaner box from a lateral arrangement to a forward arrangement relative to the V-type engine. By utilizing the frontward space and integrating with the side cowl structure, the air cleaner achieves sufficient capacity for both cylinders without increasing lateral width. The clean side chamber and dirty side chamber are arranged to efficiently utilize the available volume in the forward direction rather than expanding sideways.
Solution Approach 2:
The air cleaner box is merged with the side cowl structure, where the side cowl serves dual purposes as both a body panel and a structural component of the air cleaner assembly. The communicating portion integrates the dirty side chamber with the side cowl interior space, reducing the need for separate housing and minimizing overall size while maintaining sufficient capacity.
2Quantity of substance
If the large-size air cleaner box is arranged at a position forward than the seat and upward of the footrest, then the air cleaner capacity is improved, but the rider's leg is liable to come into contact with the air cleaner
Solution Approach 1:
The air cleaner box is positioned in the frontward direction rather than extending upward above the footrest. By arranging the air cleaner at a position forward of the seat and utilizing the forward space efficiently, the design eliminates the interference with the rider's leg while maintaining sufficient capacity through optimized internal chamber arrangement.
3Ease of operation
If the air cleaner case is arranged laterally to the V-type engine, then the air cleaner is accessible, but the lateral projection from the fuel tank increases
Solution Approach 1:
The air cleaner box is arranged in the frontward direction rather than extending laterally from the fuel tank. This repositioning reduces the lateral projection area while maintaining accessibility through the forward arrangement, allowing service access from the front or side without increasing the vehicle's overall width.
Data Source
AI summary
A pair of middle cowls is arranged at positions rightward and leftward of a vehicle component located at a position forward of an engine. Part of the right middle cowl is arranged at a position further forward than an air cleaner case. A space in the air cleaner case is divided by a filter element into a first space positioned at a position further downstream than the filter element and a second space positioned at a position further upstream than the filter element. The second space is smaller than the first space. The second space and a third space inward of the right middle cowl communicate with each other by a communicating portion. The second space, at least part of the third space, and an internal space of the communicating portion constitute a dirty side chamber of an air cleaner.