Automatic Transmission Control Apparatus for Erroneous Shift Lever Operations
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Solution Overview
Problem
Existing control systems for automatic transmissions fail to reliably inhibit range switching caused by erroneous shift lever operations, leading to engine stop and disrupted vehicle performance, especially when drivers correct their mistakes, and struggle to balance responsiveness in normal operations with preventing engine stop during high-speed driving.
Innovation Solution
A control apparatus with first and second erroneous operation determining means and corresponding inhibiting and permitting means that differentiate between erroneous and intended shift lever operations based on vehicle speed states, preventing gear shifts to reverse or forward positions during high-speed driving and allowing normal gear shifts when the shift lever is corrected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gear shift to reverse gear position is inhibited when shift lever is switched from forward range to reverse range at high vehicle speed, then engine stop is prevented, but the gear position is kept at forward third speed gear position even when driver returns shift lever to reverse range, causing vehicle to be unable to run rearward
Solution Approach 1:
The patent applies dynamics by making the inhibition control adaptive rather than static. The control apparatus dynamically adjusts the inhibition state based on real-time shift lever position feedback. When the shift lever is returned to the reverse range after an erroneous forward switch, the system detects this correction and automatically releases the inhibition, allowing the gear position to switch to reverse. This dynamic response resolves the contradiction by maintaining reliability during erroneous operations while restoring ease of operation when the driver corrects the mistake.
Solution Approach 2:
The patent implements feedback control by continuously monitoring the shift lever position and using this information to modulate the inhibition control. The control apparatus receives feedback signals from the shift lever position sensor and adjusts the gear shift inhibition accordingly. When the shift lever returns to the reverse range, the feedback mechanism triggers release of the inhibition, enabling the gear position to update to reverse. This feedback loop ensures both engine stop prevention and proper response to driver correction.
2Reliability
If gear shift to forward gear position is inhibited when shift lever is switched from reverse range to forward range at high vehicle speed, then engine stop is prevented, but the gear position is kept at reverse gear position, causing driving force to be considerably changed
Solution Approach 1:
The patent applies dynamics by making the inhibition control adaptive rather than static. The control apparatus dynamically adjusts the inhibition state based on real-time shift lever position feedback. When the shift lever is returned to the forward range after an erroneous reverse switch, the system detects this correction and automatically releases the inhibition, allowing the gear position to switch to forward. This dynamic response resolves the contradiction by maintaining reliability during erroneous operations while restoring normal driving force characteristics when the driver corrects the mistake.
Solution Approach 2:
The patent implements feedback control by continuously monitoring the shift lever position and using this information to modulate the inhibition control. The control apparatus receives feedback signals from the shift lever position sensor and adjusts the gear shift inhibition accordingly. When the shift lever returns to the forward range, the feedback mechanism triggers release of the inhibition, enabling the gear position to update to forward and restoring normal driving force.
3Speed
If predetermined period of time for range continuous setting is set to be short, then responsiveness to normal range switching is improved, but gear shift to selected range is accomplished before vehicle speed becomes low in erroneous operation, causing engine stop to occur
Solution Approach 1:
The patent applies segmentation by separating the control logic into two independent pathways: one for normal range switching and another for erroneous operation detection. The normal switching pathway uses a short predetermined period for quick responsiveness, while the erroneous operation pathway uses real-time vehicle speed monitoring with threshold-based inhibition. This segmentation allows the system to maintain high responsiveness for legitimate driver actions while providing robust protection against erroneous operations that could cause engine stop.
Solution Approach 2:
The patent applies parameter changes by dynamically adjusting the effective inhibition period based on vehicle speed conditions. Instead of using a fixed predetermined period for all situations, the system monitors vehicle speed in real-time and applies inhibition control when speed exceeds a predetermined threshold during range switching. This parameter-based approach allows quick response to normal switching at low speeds while preventing engine stop during high-speed erroneous operations.
Data Source
AI summary
There is provided a control apparatus for a vehicular automatic transmission which reliably inhibits switching between ranges caused by an erroneous operation of a shift lever and enables a vehicle to continue running normally without interfering with the operation of returning the shift lever to a normal position. When the shift lever is switched to a reverse range in a state in which a flag Flag_D_high indicative of a forward high vehicle speed assumes “1”, this operation is determined as being an erroneous operation, and gear shift to a reverse gear position is inhibited from being accomplished. When the shift lever is switched to a forward range in a state in which a flag Flag_R_high indicative of a reverse high vehicle speed assumes “1”, this operation is determined as being an erroneous operation, and gear shift to a forward gear position is inhibited from being accomplished.