Automatic Transmission Skip Shift Control via Interim Gear
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Solution Overview
Problem
Existing automatic vehicle transmission systems experience delays in acceleration response during skip downshifts, leading to elongated speed change periods that degrade the shift feeling for drivers, as the fixed order of shifting operations across gear stages can result in longer times to sense acceleration and potential shocks during stepwise skip downshifts.
Innovation Solution
A shift control system and method that employs a controller with a control map to determine interim speed ratios, allowing for smooth acceleration feel by shifting through defined regions of stimulation intensity and unconscious period, ensuring the driver senses acceleration without delay, by executing sequential shifts within moderate and intense regions to achieve the target speed ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a fixed order of shifting operation is used across gear stages to achieve skip downshift, then the transmission can execute multi-stage gear changes, but the acceleration response time is delayed and the speed change period is elongated
Solution Approach 1:
The patent applies dynamics by making the shifting order adaptive rather than fixed. The control device dynamically adjusts the sequence of gear stage shifts based on real-time acceleration requirements and vehicle state, allowing the system to optimize response time for each specific operating condition while maintaining multi-stage skipping capability.
Solution Approach 2:
The patent changes the parameter of shifting order from a static fixed sequence to a dynamic variable sequence. By adjusting the order parameters based on acceleration demands, the system can prioritize faster acceleration response when needed while still achieving the desired skip downshift across multiple gear stages.
2Ease of operation
If skip downshift is executed stepwise through interim gear stages, then the gear change can be controlled smoothly, but the driver may feel shock during the transition
Solution Approach 1:
The patent extracts the harmful shock sensation from the shifting process by selectively bypassing intermediate gear stages that would cause noticeable acceleration drops. Instead of stepping through all interim stages, the system extracts only the necessary speed ratio changes while maintaining smooth acceleration perception for the driver.
Solution Approach 2:
The patent applies skipping by allowing the transmission to rush through multiple gear stages in optimized sequences. When acceleration response is prioritized, the system can skip certain intermediate engagement steps that would otherwise cause perceptible shocks, while still achieving the target gear stage through alternative pathways.
3Device complexity
If the unconscious period and stimulation intensity are not optimized, then the control system is simpler, but the driver cannot sense acceleration increase promptly
Solution Approach 1:
The patent implements feedback by continuously monitoring acceleration sensations and adjusting the shifting sequence accordingly. The control device uses feedback from acceleration sensors and driver state to determine whether to prioritize unconscious period reduction or stimulation intensity optimization, creating a closed-loop system that responds to real-time conditions.
Solution Approach 2:
The patent applies preliminary action by pre-calculating optimal shifting sequences that account for the driver's unconscious period and stimulation intensity requirements. Before executing the skip downshift, the system determines the best order of gear stage changes to ensure acceleration is sensed promptly, preparing the optimal path in advance based on current vehicle state.
Data Source
AI summary
A shift control system and a shift control method configured to execute a skip shift smoothly are provided. The shift control system selects an interim gear stage with reference to a control map. The control map is configured to determine: an intense region where a driver is allowed to sense an increase in the acceleration sufficiently based on an unconscious period, and a stimulation intensity; and a moderate region where acceleration is increased in a mild manner. During execution of the skip shift, the acceleration is increased in a mild manner by shifting the gear stage from an initial stage to the interim gear stage, and then increased significantly by shifting the gear stage from the interim gear stage to a target gear stage.