Automatic Transmission Delay Up-Shift Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional gear shift control in automatic transmissions often results in an unpleasant 'shift busy feeling' due to repeated engine speed variations, especially during deceleration when the read-ahead vehicle speed varies slightly with brake pedal depression, leading to continuous up-shifts despite the driver's intention for deceleration.
Innovation Solution
A control apparatus for automatic transmissions that estimates read-ahead vehicle speed based on acceleration and actual vehicle speed, incorporating a delay up-shift control mechanism to inhibit up-shifts for a predetermined time after down-shifts in a coast state, preventing unnecessary engine speed variations and eliminating the shift busy feeling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gear shift control is executed based on read-ahead vehicle speed during deceleration, then driveability is improved and gear shift delay is prevented, but shift busy feeling occurs due to repeated up-shifts after down-shift
Solution Approach 1:
The control device applies preliminary anti-action by detecting when a down-shift is executed during deceleration and subsequently preventing up-shift requests from being processed within a predetermined time window. This preemptive blocking mechanism counteracts the harmful effect of repeated up-shifts before they can occur, eliminating the shift busy feeling while maintaining accurate gear shift timing based on read-ahead vehicle speed
2Measurement precision
If read-ahead vehicle speed is used for gear shift control, then future gear shift timing is improved, but unnecessary engine speed variation occurs due to slight brake pedal variations
Solution Approach 1:
The control device employs feedback by continuously monitoring the relationship between down-shift execution and subsequent up-shift requests. When a down-shift is detected during deceleration, the system feeds back this information to block future up-shift requests within a predetermined time period, thereby stabilizing engine speed and preventing unnecessary variations caused by slight brake pedal movements
Data Source
AI summary
In a control apparatus for an automatic transmission in which a read-ahead vehicle speed which is a future vehicle speed is estimated on a basis of an acceleration and an actual vehicle speed and a gear shift control is carried out on a basis of the read-ahead vehicle speed and other driving parameters, a start of an up-shift is inhibited even if a determination of the up-shift is made for a predetermined time after a down-shift in a coast state has occurred and executing the up-shift after the predetermined time is elapsed. Consequently, while an unpleasant feeling given to a driver is suppressed, an appropriate gear shift is executable.