Straddled Vehicle CVT Control for Vibration Suppression
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Solution Overview
Problem
Straddled vehicles, such as motorcycles, experience delayed acceleration response and uncomfortable vibrations when attempting to achieve fuel-efficient running due to the high inertial mass and engine speed range, which is not effectively addressed by existing drive force control devices designed for four-wheeled automobiles.
Innovation Solution
A control system for straddled vehicles that includes an electronically controlled throttle valve and continuously variable transmission, utilizing a control device with separate engine and CVT controllers to manage engine revolution speed and gear ratio, ensuring prompt suppression of vibrations while maintaining acceleration responsiveness and fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the engine revolution speed is decreased to achieve fuel efficient running, then fuel efficiency is improved, but acceleration response is delayed
Solution Approach 1:
The control device dynamically adjusts the target engine revolution speed based on the operation amount of the accelerator. When the accelerator operation amount exceeds a predetermined threshold, the control device prioritizes acceleration responsiveness over fuel efficiency, allowing the engine revolution speed to increase promptly. This dynamic switching between fuel-efficient mode and acceleration mode resolves the contradiction by adapting the control strategy to the driver's instantaneous intent.
2Use of energy by moving object
If the engine revolution speed is decreased for fuel efficient running, then fuel efficiency is improved, but vibrations occur which disturb ride quality
Solution Approach 1:
The control device continuously monitors the accelerator operation amount and uses this feedback to determine the appropriate control mode. When vibration is detected (indicated by significant accelerator operation), the system switches from fuel-efficient mode to acceleration mode, which maintains higher engine revolution speeds that avoid the vibration-prone range. This feedback mechanism ensures that vibrations are suppressed while maintaining fuel efficiency during normal operation.
3Use of energy by moving object
If the gear ratio is decreased to achieve fuel efficient running, then fuel efficiency is improved, but the inertial loss of rotary members delays acceleration
Solution Approach 1:
The control device dynamically adjusts the target gear ratio based on the accelerator operation amount. During normal cruising, the system maintains a higher gear ratio for fuel efficiency. However, when the accelerator operation amount exceeds the threshold, the control device promptly decreases the gear ratio to reduce inertial loss and improve acceleration response. This dynamic adjustment resolves the contradiction between fuel efficiency and acceleration performance.
Data Source
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AI summary
A straddled vehicle includes : an electronically controlled continuously variable transmission; a target output calculation unit (16B) being configured to calculate a target output based on information relating to an accelerator operation amount and information relating to a vehicle speed; a basic engine revolution speed calculation unit (11) being configured to calculate a basic engine revolution speed based on the information relating to the vehicle speed; a target engine revolution speed calculation unit (13) being configured to calculate a target engine revolution speed by adding a correction revolution speed to the basic engine revolution speed, hold the correction revolution speed, and perform lag processing on a change in the correction revolution speed; and a target gear ratio calculation unit (14) being configured to calculate a target gear ratio of the electronically controlled continuously variable transmission based on the target engine revolution speed.