Motorcycle Engine Mounting and Cooling Duct Design
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Solution Overview
Problem
Existing motorcycle designs with engine units supported by link mechanisms experience reduced coolability due to deformation in flexible cooling ducts and responsiveness issues during acceleration, as the flexible ducts deform under external forces and negative pressure, leading to reduced air intake and delayed throttle response.
Innovation Solution
A motorcycle design where the engine unit is directly pivotally mounted on the body frame using an elastic member, eliminating the need for a separate linking mechanism, with a cooling duct having a flexible portion that extends adjacent to the pivot axis, allowing only vertical movement and maintaining structural integrity under external forces, and a balancer mechanism to suppress engine vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a link mechanism is used to support the engine unit, then engine vibrations are isolated from the rider, but the flexible cooling duct deforms under external forces and negative pressure, reducing air intake and coolability
Solution Approach 1:
The patent removes the link mechanism from the engine support system, directly mounting the engine unit to the body frame. This eliminates the complex swinging motion that causes flexible duct deformation while maintaining vibration isolation through alternative means (engine mounting design). The extraction of the link mechanism resolves the contradiction by prioritizing cooling duct stability over vibration isolation through linkage.
Solution Approach 2:
The patent changes the mounting configuration from a link mechanism with complex degrees of freedom to a direct pivot mounting with constrained motion. This parameter change in the support system reduces the deformation of the flexible cooling duct while maintaining necessary engine movement capabilities, thus preserving coolability.
2Adaptability or versatility
If a link mechanism is used to support the engine unit, then vertical swinging is accommodated, but the direction of swinging becomes complex (vertical and longitudinal), requiring complex flexible portion structure that is prone to deformation
Solution Approach 1:
The patent extracts the link mechanism and replaces it with direct pivotal mounting of the engine unit to the body frame. This simplifies the swinging accommodation to a single vertical axis rotation, eliminating the need for complex flexible duct structures that can deform under multiple directions of motion.
Solution Approach 2:
Instead of using a link mechanism to create complex swinging motion to accommodate engine movement, the patent inverts the approach by directly pivoting the engine on a fixed axis, simplifying the motion path and reducing flexible duct complexity.
3Adaptability or versatility
If a link mechanism is used to support the engine unit, then vertical swinging is enabled, but throttle response lag occurs during starting and acceleration
Solution Approach 1:
The patent removes the link mechanism that caused response lag and implements direct pivotal mounting of the engine unit. This eliminates the mechanical slack and complex motion transmission that delayed throttle response, enabling more immediate engine response during starting and acceleration while maintaining necessary swinging capability through the simplified pivot connection.
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 design enhances coolability by maintaining air intake and reduces responsiveness lag during acceleration, providing a more direct feel when starting and accelerating, while minimizing vibration transmission to the rider.
Implementation Method 1
an engine unit directly pivotally mounted on the body frame using an elastic member
Implementation Method 2
a balancer mechanism which includes a balancer shaft and is adapted to suppress engine vibrations due to a primary, inertial force
Data Source
Figure 1
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AI summary
A motorcycle comprises a body frame and an engine unit (8) directly pivotally mounted on the body frame about a pivot axis (a), wherein said engine unit (8) comprises a belt continuously variable transmission accommodated within a belt chamber (8b). The motorcycle also comprises a cooling duct (60) adapted to communicate cooling air into the belt chamber (8b), wherein said cooling duct (60) comprises a flexible portion which extends adjacent the engine pivot axis (a).