Lean Vehicle Gear-Shift Controller Adaptive Clutch Threshold

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Solution Overview

Problem

Existing gear-shift controllers for leaning vehicles, such as those described in Patent Document 1, disengage the clutch during U-turns, leading to a non-transfer state of driving force, making it difficult for drivers to control the vehicle's posture during turns due to delayed re-engagement of the driving force.

Innovation Solution

A gear-shift controller for a leaning vehicle that adjusts the threshold for disengaging the driving force based on the vehicle's posture, setting a lower threshold for lean states compared to upright states, using a vehicle body posture detector to determine the lean angle or yaw rate and adjust the engine speed threshold accordingly, thereby minimizing the non-transfer state during turns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If the clutch is disengaged during U-turn to reduce engine speed, then the engine speed control is improved, but the driving force transfer is interrupted causing delayed response

Engineering Contradiction:
Improveengine speed controlVSAvoiddriving force re-engagement time
Core Design Contradiction:
Use of energy by moving objectVSLoss of time

Solution Approach 1:

The patent applies dynamics by making the clutch control strategy adaptive rather than static. The gear-shift controller dynamically adjusts clutch engagement/disengagement timing based on detected vehicle state (turning vs. non-turning), allowing the system to optimize engine speed control while minimizing driving force transfer interruption through conditional control logic

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the control parameter threshold for clutch disengagement based on vehicle state. By detecting whether the vehicle is in a turning state, the system modifies the engine speed threshold at which clutch disengagement occurs, thereby maintaining driving force transfer during turns while still enabling engine speed control during non-turning deceleration

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If the clutch is disengaged during turning, then the engine speed is reduced, but the vehicle posture control becomes difficult

Engineering Contradiction:
Improveengine speedVSAvoidvehicle posture control
Core Design Contradiction:
Use of energy by moving objectVSEase of operation

Solution Approach 1:

The patent implements feedback by using a vehicle state detector to monitor whether the vehicle is in a turning state, and feeding this information back to the gear-shift controller. This feedback loop enables the controller to adjust clutch control strategy in real-time, maintaining driving force transfer during turns to ensure responsive vehicle posture control while still managing engine speed appropriately

Inventive Principle:
Principle #23Feedback

3Ease of manufacture

If the driving force is put in non-transfer state during turn, then the clutch engagement is smooth, but the acceleration response is delayed

Engineering Contradiction:
Improveclutch engagement smoothnessVSAvoidacceleration response speed
Core Design Contradiction:
Ease of manufactureVSSpeed

Solution Approach 1:

The patent changes the control parameter (engine speed threshold for clutch disengagement) based on vehicle state. During turning maneuvers, the system maintains a higher threshold that prevents clutch disengagement, ensuring rapid acceleration response. During non-turning deceleration, the threshold is lowered to enable smooth clutch engagement/disengagement, thereby optimizing both acceleration response and clutch engagement characteristics under different operating conditions

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3901025B1Lean vehicle
Publication Date: 2022.09.28 YAMAHA MOTOR CO LTD
  • EP3901025B1 patent drawingFigure 1
  • EP3901025B1 patent drawingFigure 2
  • EP3901025B1 patent drawingFigure 3

AI summary

A leaning vehicle that has a small posture change when turning and that a driver can easily operate during the turning is provided. A vehicle 1 that is a leaning vehicle includes a lean detector 61 configured to detect a posture of a vehicle body 2, a gear-type multi-stage automatic transmission 12 including a plurality of gear stages and a clutch 40 configured to switch between a transfer state and a non-transfer state of a driving force from an engine 11 to the plurality of gear stages, and a controller 7 configured to put, if engine speed is smaller than an engine speed threshold, the driving force in the non-transfer state in the multi-stage automatic transmission 12. The controller 7 sets, if the lean detector 61 determines that the vehicle 1 is travelling in an upright state, the engine speed threshold at which the driving force is put in the non-transfer state in the multi-stage automatic transmission 12 to a first engine speed threshold and sets, if the lean detector 61 determines that the vehicle 1 is turning in a lean state, the engine speed threshold to a second engine speed threshold that is smaller than the first engine speed threshold.