Vehicle Electronic Control Unit Throttle Regulation for Centrifugal Clutch Disconnection
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Solution Overview
Problem
Saddle-ride type vehicles with belt-type continuously variable transmissions and centrifugal clutches can experience sudden starts when parked on a center stand, leading to unintended wheel contact and potential catalyst deterioration due to increased engine rotational speed during idling.
Innovation Solution
A vehicle electronic control unit that includes an electronic-control throttle control system, which calculates a target throttle opening degree based on an accelerator opening degree sensor and feedback control to maintain a disconnected state of the centrifugal clutch when the vehicle is parked, and adjusts throttle valve opening rates to prevent sudden accelerations and engine speed increases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the ignition timing of the engine is delayed to suppress engine rotational speed increase during idling, then the centrifugal clutch remains disconnected, but the combustion chamber temperature increases and catalyst deterioration occurs
Solution Approach 1:
The system changes the throttle opening degree parameter to regulate engine rotational speed during idling on center stand, preventing centrifugal clutch connection while avoiding excessive combustion chamber temperature increase that would occur with ignition timing delay alone
2Speed
If the throttle valve opens rapidly in response to accelerator operation, then the driver's intent is quickly responded to, but the centrifugal clutch may connect unexpectedly causing sudden vehicle movement
Solution Approach 1:
The system dynamically adjusts the throttle opening speed based on the vehicle state (whether on center stand). When detected on center stand, the throttle opens slowly to prevent unintended clutch connection; when not on center stand, normal rapid opening is permitted for responsive acceleration
Solution Approach 2:
The stand state detection unit provides feedback to the electronic control unit, which then adjusts throttle control accordingly. This closed-loop feedback ensures the throttle opening behavior is appropriate for the current vehicle support state, preventing sudden movements
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The control unit effectively suppresses sudden starts and catalyst deterioration by maintaining the centrifugal clutch in a disconnected state and regulating throttle opening degrees to prevent unnecessary connections and rapid accelerations, ensuring safe parking and reducing engine temperature-related friction issues.
Implementation Method 1
when the rotational speed of the engine increases with opening of a throttle valve according to an accelerator operation of a driver, a clutch shoe abuts onto the inner circumference of a clutch outer against a clutch spring because of a centrifugal force, whereby the clutch is connected
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
In a vehicle electronic control unit 10, a target throttle-opening-degree calculation unit 19 of an electronic-control throttle control unit C regulates a target throttle opening degree TRG to cause a rotational speed NE of an engine 2 to fall within a range of a rotational speed that enables a centrifugal clutch 5 to keep a disconnected state when a state of a center stand 6 detected by a center-stand-state detection unit 15 is a standing state.