CVT Shift Position Alert for Smoother Straddled Vehicle Starts

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Solution Overview

Problem

Existing straddled vehicles with continuously variable transmissions (CVT) face issues where the shift position may not be at the LOW position when the engine starts, leading to discomfort and a push feeling due to early engagement of the centrifugal clutch.

Innovation Solution

Incorporating a sensor to detect the shift position, a controller to acquire this information, and a notification unit to alert the driver if the shift position is not at the LOW position when the main switch is turned on, using visual and auditory signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the main switch is turned off while the straddled vehicle is traveling, then the motor stops and the shift position is fixed, but when the engine starts at a position other than the LOW position, the ride comfort deteriorates due to early centrifugal clutch engagement

Engineering Contradiction:
Improveshift position stabilityVSAvoidride comfort
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The notification unit activates before engine start to alert the driver about the shift position. By providing advance notification when the shift position is not at the LOW position, the system allows the driver to take preliminary action (manually adjusting the shift position) before the harmful effect of early centrifugal clutch engagement occurs during engine start

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The notification unit serves as an intermediary between the shift position detection system and the driver. It translates the technical state (shift position) into driver-friendly information (visual/auditory alerts), enabling the driver to make informed decisions about whether to adjust the shift position before starting the engine

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If the shift position is maintained at a position other than the LOW position when the main switch is off, then the device complexity is reduced, but the engine starts slowly with a push feeling

Engineering Contradiction:
Improvetransmission control systemVSAvoidengine start speed
Core Design Contradiction:
Device complexityVSSpeed

Solution Approach 1:

The notification unit acts as an intermediary that provides information to the driver without requiring complex automated control mechanisms. This simple alert system enables the driver to manually intervene if needed, achieving fast engine start performance without adding complex automated shift position control systems

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4671572A1Straddled vehicle
Publication Date: 2025.12.31 YAMAHA MOTOR CO LTD
  • EP4671572A1 patent drawingFigure 1
  • EP4671572A1 patent drawingFigure 2
  • EP4671572A1 patent drawingFigure 3

AI summary

There is disclosed a straddled vehicle (1) including an engine (11), a continuously variable transmission (21), an electric motor (31), a shift position sensor (27), a controller (40), a main switch (32), and a notification unit (50); the engine (11) generating power; the continuously variable transmission (21) transmitting power of the engine (11) to a rear wheel (5); the electric motor (31) changing a shift position of the continuously variable transmission (21); the shift position sensor (27) detecting the shift position of the continuously variable transmission (21); the controller (40) acquiring a detection result of the shift position sensor (27); the notification unit (50) being electrically connected to the controller (40); the notification unit (50) receiving information from the controller (40); when an initial position is at a position other than a LOW position, the controller (40) causing the notification unit (50) to output an alarm.