Throttle Control System for Rapid Closing Collision Prevention
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Solution Overview
Problem
Existing throttle control systems for throttle-by-wire systems often result in collisions between the throttle valve and the full-close stopper during rapid closing operations, leading to overshoot, deformation, and abrasion of the stopper and drive gear, and fail to effectively manage rapid throttle operations.
Innovation Solution
A throttle control system that calculates a target throttle opening degree and limits its change amount using a correction term when rapid closing is detected, reducing the change amount to prevent collisions and ensuring smooth operation, maintaining the limitation until the change amount falls below a predetermined threshold and converging to an idling opening degree.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fully-closed limiter position is gradually moved toward the fully closed position to avoid collision, then the collision with the stopper is prevented, but the throttle valve cannot respond rapidly to rapid closing operations
Solution Approach 1:
The patent applies dynamics by making the limiter position adjustable and variable rather than fixed. The limiter position is dynamically changed based on the throttle valve's current position and operation state, allowing it to be far from the stopper during normal operation (enabling rapid response) and gradually approached during closing operations (preventing collision). This dynamic adjustment resolves the contradiction between rapid response capability and collision prevention.
Solution Approach 2:
The patent changes the parameter of limiter position based on operating conditions. When the throttle valve is in normal operation, the limiter position is set to allow rapid closing. When the throttle valve approaches the closed position, the limiter position is gradually adjusted to prevent collision. This parameter change strategy enables the system to achieve both rapid response and collision prevention by adapting the limiter position to different operational phases.
2Ease of operation
If the throttle valve is rapidly closed by the operating device, then the driveability is maintained, but the throttle valve collides with the full-close stopper causing overshoot and wear
Solution Approach 1:
The patent applies preliminary action by pre-positioning the limiter far from the full-close stopper position. This preliminary setup allows the throttle valve to be rapidly closed without immediate risk of collision. As the valve approaches the closed position, the limiter is gradually moved to prevent collision before it occurs. This preliminary positioning strategy maintains driveability while preventing harmful collisions and wear.
3Speed
If the limiter position is fixed away from the fully closed position, then rapid closing operations are enabled, but collision with the stopper cannot be prevented
Solution Approach 1:
The patent transforms the static limiter position into a dynamic one that changes based on the throttle valve's operation. During rapid closing operations, the limiter remains far from the stopper to maintain high closing speed. As the valve approaches the closed position, the limiter is dynamically adjusted to prevent collision. This dynamic behavior resolves the contradiction between maintaining rapid closing speed and preventing collision.
Data Source
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AI summary
To limit a rapid change in a change amount of a target opening degree due to a rapid closing operation of a throttle grip, and thus to prevent a throttle valve from overshooting. A target TH opening degree change amount calculating unit (26) calculates a change amount of a target throttle opening degree ΔTHCMD. In accordance with whether or not the change amount of the target throttle opening degree ΔTHCMD is not less than a predetermined control start threshold, a collision prevention process determining unit (27) determines whether or not a throttle grip (21) has been operated to rapidly close. When the rapid closing operation of the throttle grip (21) is detected, a change-amount basic value calculating unit (28) calculates a change-amount basic value of the target throttle opening degree. A correction term calculating unit (29) inputs to a multiplying unit (30) a correction term for correcting the change-amount basic value. The multiplying unit (30) multiplies the change-amount basic value by the correction term, and outputs a change amount of the target throttle opening degree thus calculated. The correction term is set to have a value not more than 1.0 in accordance with the target TH opening degree.