Clutch State Detection via Rotational Speed Comparison for Smooth Shifting
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Solution Overview
Problem
Existing engine control systems for clutchless shifting in saddle-straddling vehicles often reduce the traveling feeling of riders, especially for less skilled riders, due to difficulties in adjusting engine outputs to smoothly disconnect gears without using clutch operations.
Innovation Solution
A control system that uses rotational speed detectors to determine the engaged or disengaged state of the clutch, adjusting engine output to facilitate smooth shifting by reducing engagement force between gears and inhibiting output adjustments when the clutch is disengaged, thereby preventing shift shocks and maintaining the traveling feeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If engine output is controlled during clutchless shifting, then shifting smoothness is improved, but traveling feeling is reduced
Solution Approach 1:
The system dynamically adjusts engine output based on the clutch engagement state detected by rotational speed sensors. When the clutch is engaged, the engine output is controlled to facilitate smooth shifting. When the clutch is disengaged, the engine output control is inhibited, preserving the natural traveling feeling. This dynamic adaptation resolves the contradiction by applying different control strategies based on operational conditions.
2Reliability
If limit switch is provided to detect clutch operation, then clutchless shifting control is prevented, but traveling feeling is still reduced
Solution Approach 1:
The patent replaces the mechanical limit switch system with a sensor-based rotational speed detection system. By comparing the rotational speeds of the crankshaft and transmission input shaft, the system accurately determines clutch engagement state without using mechanical switches. This substitution eliminates the limitation of limit switches while maintaining accurate clutch state detection, thereby preserving traveling feeling during normal operation.
3Ease of operation
If engine output is adjusted during shifting, then gear disconnection becomes easier, but shift shock occurs when clutch is disengaged
Solution Approach 1:
The system uses rotational speed sensors to continuously monitor the crankshaft and transmission input shaft speeds, providing feedback on clutch engagement state. Based on this feedback, the control system intelligently decides whether to adjust engine output during shifting. When the clutch is disengaged (detected by speed difference), engine output adjustment is inhibited, preventing shift shock. This feedback mechanism resolves the contradiction by conditionally applying engine output control.
Data Source
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AI summary
In a control system according to the present invention, the rotational speed of a crank (2) is calculated as an actual rotational speed based on the detected value of a crank sensor (SE2). The rotational speed of a main shaft (5a) is calculated based on the detected value of a main shaft sensor (SE5). An estimated value of the rotational speed of the crank (2) is calculated as an operated rotational speed based on the calculated rotational speed of the main shaft (5a) and a primary reduction gear ratio. The state of a clutch (3) is determined based on the actual rotational speed and the operated rotational speed. An ECU (50) allows the adjustment of an output of an engine (107) when the clutch (3) is in an engaged state, while inhibiting the adjustment of the output of the engine (107) when the clutch (3) is in a disengaged state.