Motorcycle Engine Speed Control During Gear Shifts

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Solution Overview

Problem

During gear changes in motorcycle transmissions, there is a risk of unintended engine rotation speed increases due to misjudged gear engagement, leading to torque interruption and uncomfortable riding experiences.

Innovation Solution

A rotation speed control device that sets a second upper limit rotation speed lower than the first upper limit when the transmission is in a neutral or intermediate neutral state during gear changes, triggering over-speed rotation prevention control to restrict engine rotation speed and prevent unintended increases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If gear change operation is performed in constant-mesh transmission, then gear switching capability is improved, but gear disengagement occurs causing unintended engine rotation speed increase

Engineering Contradiction:

Improvegear switching capabilityVSAvoidgear engagement reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The control device performs preliminary detection of gear position (neutral state or intermediate neutral state) before the gear change is complete, and preemptively executes over-speed rotation prevention control to prevent unintended engine rotation speed increases that would occur after gear disengagement

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The control device continuously monitors gear position through detection means and provides feedback control by adjusting throttle valve opening degree or fuel injection amount based on detected neutral/intermediate neutral states, thereby preventing unintended engine speed increases during gear change operations

Inventive Principle:

Principle #23Feedback

2Reliability

If over-speed rotation prevention control is performed during neutral state, then engine rotation speed is suppressed, but rider operation flexibility is reduced

Engineering Contradiction:

Improveengine rotation speed controlVSAvoidrider operation flexibility

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The control device dynamically adjusts the upper limit rotation speed threshold based on detected gear position, applying over-speed prevention control with lower thresholds during neutral/intermediate neutral states while allowing normal operation during engaged states, thereby adapting control stringency to operational context

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The control device changes the parameter of upper limit rotation speed threshold based on gear position detection, setting different thresholds for neutral/intermediate neutral states versus engaged states, allowing flexible control that adapts to different operational conditions without restricting rider flexibility during normal operation

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS10975781B2Rotation speed control device

Publication Date: 2021.04.13 SUZUKI MOTOR CORP

AI summary

There is provided an engine rotation speed control device for performing over-speed rotation prevention control to decrease an engine rotation speed if the engine rotation speed exceeds a first upper limit rotation speed. If a gear position of a transmission is a neutral state or an intermediate neutral state in which predetermined gears are not engaged with each other in the middle of a gear change operation of the transmission, a second upper limit rotation speed which is lower than the first upper limit rotation speed is set. If the engine rotation speed at the time when the gear position of the transmission is the neutral state or the intermediate neutral state is higher than the second upper limit rotation speed, the over-speed rotation prevention control is performed.