Straddled Vehicle Exhaust Device Catalyst Rigidity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In straddled vehicles, increasing the size of catalysts in exhaust devices leads to increased weight, causing vibration and displacement issues, which are difficult to manage due to restricted support positions on the vehicle body frame and engine body.
Innovation Solution
The design includes a straddled vehicle with a turbocharger and an exhaust device featuring a plurality of catalysts arranged along the exhaust pipe, where the second catalyst is at least half the volume of the first, with specific internal area variations to increase rigidity and prevent displacement, and the exhaust pipe is bent at corners to distribute weight and reduce vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the size of catalysts is increased to improve purification performance, then the purification performance is improved, but the weight of the exhaust device increases causing vibration and displacement issues
Solution Approach 1:
The exhaust pipe is divided into multiple sections with different rigidity characteristics. The first section (upstream of first catalyst) has high rigidity with minimum internal area ≥ maximum internal area in the second section. The second section (between catalysts) has moderate rigidity. The third section (downstream of second catalyst) has lower rigidity with maximum internal area ≥ maximum internal area in the fourth section. This segmentation allows the exhaust device to accommodate the weight of large catalysts while maintaining purification performance through strategic rigidity distribution.
Solution Approach 2:
Different sections of the exhaust pipe are designed with different rigidity properties to address local requirements. The upstream section near the turbocharger has high rigidity to handle vibration and weight. The section between catalysts has moderate rigidity. The downstream section has lower rigidity to reduce overall weight and vibration. This local quality approach allows large catalysts to be used for purification while managing the weight-induced vibration and displacement problems through varied structural properties in different locations.
2Reliability
If the size of catalysts is increased to improve purification performance, then the purification performance is improved, but the displacement of the exhaust device relative to the vehicle body frame and engine body increases
Solution Approach 1:
The exhaust pipe is segmented into four sections with progressively varying rigidity characteristics. The first section (upstream of first catalyst) has high rigidity to minimize displacement near the engine. The second section (between catalysts) has moderate rigidity. The third section (downstream of second catalyst) has lower rigidity with increased internal area to accommodate catalyst weight while allowing controlled displacement. This segmentation enables large catalysts for purification while managing exhaust device displacement through distributed rigidity.
Solution Approach 2:
Different sections of the exhaust pipe are designed with different rigidity properties to address local displacement requirements. The upstream section has high rigidity to maintain position near the turbocharger and engine. The section between catalysts has moderate rigidity. The downstream section has lower rigidity to reduce overall displacement sensitivity. This local quality approach allows large catalysts to be used for purification while managing displacement issues through varied structural properties in different locations.
3Loss of energy
If the exhaust pipe internal area is increased to reduce exhaust resistance, then the exhaust resistance is reduced, but the rigidity of the exhaust pipe decreases leading to more vibration and displacement
Solution Approach 1:
The exhaust pipe is divided into sections with different internal area characteristics. The first section (upstream of first catalyst) maintains smaller internal area for high rigidity. The second section (between catalysts) has moderate internal area. The third section (downstream of second catalyst) increases internal area to reduce exhaust resistance while the overall segmented structure maintains sufficient rigidity through the upstream high-rigidity sections. This segmentation allows reduced exhaust resistance in downstream sections while maintaining overall structural strength.
Solution Approach 2:
Different sections of the exhaust pipe are designed with different internal area properties to balance exhaust resistance and rigidity locally. The upstream section has smaller internal area for high rigidity near the engine and turbocharger. The downstream section has larger internal area to reduce exhaust resistance where the exhaust flow is already established. This local quality approach reduces overall exhaust resistance while maintaining necessary rigidity in critical upstream sections.
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 configuration allows for larger catalysts while minimizing displacement and vibration, enhancing the exhaust device's rigidity and reducing exhaust resistance, thereby improving purification performance and stability.
Implementation Method 1
a turbocharger for compressing intake air by the exhaust gas flowed out from the engine body
Implementation Method 2
compressing intake air by the exhaust gas flowed out from the engine body
Data Source
Figure 1
Figure 2
Figure 3
AI summary
To provide a straddled vehicle that allows a catalyst to be large and large displacement of an exhaust device relative to a vehicle body frame and an engine body to be suppressed. The plurality of catalysts is not arranged in the corner section. The volume of the second catalyst is more than or equal to half of the volume of the first catalyst. The maximum value of the exhaust pipe internal area between the upstream end of the exhaust pipe and the upstream end of the first catalyst is more than or equal to the maximum value of the exhaust pipe internal area between the upstream end of the first catalyst and the downstream end of the first catalyst. The maximum value of the exhaust pipe internal area between the downstream end of the first catalyst and the upstream end of the second catalyst is more than or equal to the maximum value of the exhaust pipe internal area between the upstream end of the second catalyst and the downstream end of the second catalyst.