Idle Speed Control for Centrifugal Clutch Engagement
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Solution Overview
Problem
Vehicles equipped with electronic continuously variable transmissions (ECVT) and idle speed control devices experience undesirable speed increases when the throttle is closed, leading to poor drivability due to the engagement of the centrifugal clutch and inappropriate transmission gear ratios.
Innovation Solution
A control system that includes a clutch engaged and disengaged based on rotational speed, with an idle speed control device that suppresses or stops idle speed control when the clutch is engaged or abnormalities in the transmission are detected, using sensors to monitor and adjust the transmission gear ratio and clutch engagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If idle speed control is activated to adjust engine idle rotational speed, then engine performance is improved, but the vehicle speed increases unintentionally when the clutch is engaged
Solution Approach 1:
The idle speed control device dynamically adjusts its operation based on clutch engagement status. When the clutch is engaged, the control device stops or suppresses idle speed control to prevent unintended vehicle speed increase. When the clutch is disengaged, normal idle speed control is restored. This dynamic adaptation resolves the contradiction between maintaining engine performance and ensuring proper drivability.
Solution Approach 2:
The control unit continuously monitors clutch engagement status and provides feedback to the idle speed control device. Based on this feedback, the control device modifies its operation accordingly - stopping idle speed control when clutch engagement is detected and resuming it when the clutch is disengaged. This feedback mechanism prevents the harmful effect of unintended speed increase while preserving engine performance benefits.
2Productivity
If the transmission gear ratio is adjusted to improve vehicle performance, then the vehicle may increase speed even when the throttle is closed, but this causes poor drivability
Solution Approach 1:
The control unit detects clutch engagement status in advance and preemptively stops or suppresses idle speed control before unintended speed increase can occur. This preliminary anti-action prevents the harmful effect of speed increase against rider intention, resolving the contradiction between vehicle performance and drivability.
3Power
If the clutch is engaged to transmit power to the drive wheel, then power transmission is improved, but idle speed control causes unintended speed increase
Solution Approach 1:
The idle speed control device dynamically changes its operation mode based on clutch engagement status. When the clutch is engaged for power transmission, the control device stops or suppresses idle speed control to eliminate the harmful unintended speed increase. When the clutch is disengaged, normal idle speed control is restored. This dynamic behavior resolves the contradiction between power transmission and preventing harmful speed increase.
Solution Approach 2:
The control unit continuously monitors clutch engagement status and provides real-time feedback to the idle speed control device. When clutch engagement is detected, the feedback triggers the control device to stop or suppress idle speed control, preventing the harmful effect of unintended speed increase while allowing power transmission to proceed normally.
Data Source
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AI summary
A two-wheeled motorized vehicle (1) is provided with a rear wheel (3) as a drive wheel, an engine (10), a transmission (20), a centrifugal clutch (25), an idle speed control device (9), and an ECU (7). The transmission (20) has a crankshaft (11) as an input shaft and an output shaft (22a1). The centrifugal clutch (25) is located between the output shaft (22a1) and the rear wheel (3). The centrifugal clutch (25) is engaged and disengaged according to the rotational speed of the output shaft (22a1). The idle speed control device (9) performs idle speed control to adjust the idle rotational speed of the engine (10). The ECU (7) suppresses or stops the idle speed control when the centrifugal clutch (25) is engaged.