Three-Wheeled Straddle-Seat Vehicle Engine Layout
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Solution Overview
Problem
Three-wheeled straddle-seat vehicles face challenges in enhancing driving experience and dynamics due to differences in weight distribution, ergonomics, and component layout compared to motorcycles and all-terrain vehicles, requiring innovative solutions for improved stability and maneuverability.
Innovation Solution
The design incorporates a horizontally and longitudinally extending engine output shaft connecting the crankshaft to a transmission assembly, with a fuel tank positioned between the transmission and seat, and a continuously variable transmission (CVT) system that includes a primary and secondary pulley with a belt, along with a transfer case and driveshaft, optimized for weight distribution and ergonomic considerations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the engine and transmission components are arranged to achieve a low center of gravity and slim profile, then vehicle stability and maneuverability are improved, but the complexity of component layout and weight distribution optimization increases
Solution Approach 1:
The patent positions the engine output shaft horizontally and longitudinally to extend toward the rear of the vehicle, utilizing the longitudinal dimension to achieve a low center of gravity while maintaining a slim profile. The fuel tank is positioned between the transmission and seat, optimizing vertical and longitudinal space arrangement to improve weight distribution without increasing lateral complexity.
Solution Approach 2:
The continuously variable transmission (CVT) system with primary and secondary pulleys enables dynamic adjustment of gear ratios, allowing the vehicle to adapt to different driving conditions. This dynamic transmission system, combined with the transfer case and driveshaft, optimizes power delivery while maintaining the low center of gravity configuration for improved stability and maneuverability.
2Ease of operation
If a continuously variable transmission (CVT) system with primary and secondary pulleys is used, then driving performance and maneuverability are enhanced, but the device complexity and manufacturing cost increase
Solution Approach 1:
The CVT system with primary and secondary pulleys is integrated with the transfer case and driveshaft to create a multi-functional transmission assembly that handles both variable ratio adjustment and power delivery to the rear wheel. This universal transmission system enhances driving performance across different terrains and conditions while consolidating multiple functions into a single integrated design.
3Stability of the object's composition
If the crankshaft rotation axis is positioned below the wheel rotation plane to achieve a low center of gravity, then vehicle stability is improved, but the engine design and component integration become more difficult
Solution Approach 1:
The engine output shaft is oriented horizontally and longitudinally to extend toward the rear of the vehicle, utilizing the longitudinal dimension to achieve a low center of gravity. This dimensional repositioning allows the crankshaft rotation axis to be located below the wheel rotation plane while maintaining manufacturability through standard engine mounting configurations adapted to the longitudinal layout.
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A vehicle has a vehicle frame, two front wheels, a rear wheel. An engine with at least one cylinder is mounted to the vehicle frame such that a cylinder plane extends generally longitudinally and vertically. At least a portion of the at least one cylinder is disposed forward of a front wheel plane. A transmission assembly disposed longitudinally rearward of the engine. A straddle seat is disposed at least in part longitudinally rearward of the transmission assembly. The engine is entirely disposed between a center of the left footrest and a center of the right footrest in the lateral direction.