Vehicle Control System for Dynamic Downshifting Selection
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Solution Overview
Problem
Existing vehicle control systems for automatic transmissions often fail to consistently improve acceleration response and shift feel, as skip shifting may not always enhance these factors, and the selection between skip and stepwise shifting is not optimally managed based on driver input and vehicle conditions.
Innovation Solution
A vehicle control system that uses a controller to evaluate and select between skip shifting and stepwise shifting based on an accelerator evaluation index, calculating the operating speed and predicted accelerator opening to determine the most suitable downshifting method for improved acceleration response and shift feel, by comparing evaluation scores for each shifting method.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If skip shifting is executed to shift the gear stage directly to the target stage at least two stages lower, then the shifting response time is shortened, but the shift feel and acceleration response may not be improved in every situation
Solution Approach 1:
The system dynamically selects between skip shifting and stepwise shifting based on real-time evaluation of accelerator operation conditions. The controller calculates an evaluation index from accelerator opening and operating speed, and adaptively chooses the shifting method that maximizes acceleration feel, thereby making the shift feel consistently improved across different driving situations while maintaining short response time when appropriate.
Solution Approach 2:
The system changes the shifting control parameters based on the evaluation index. When the evaluation index indicates favorable conditions, skip shifting parameters are selected to minimize time loss. When conditions are less favorable, stepwise shifting parameters are selected to maintain reliable shift feel, thus optimizing the trade-off between response time and shift feel consistency.
2Reliability
If stepwise shifting is executed to shift the gear stage to the target stage in order, then the shift feel and acceleration response are improved in some situations, but the shifting response time is increased
Solution Approach 1:
The system dynamically adjusts the shifting strategy based on real-time accelerator operation evaluation. When the evaluation index suggests that stepwise shifting will improve acceleration feel, the controller executes stepwise shifting. Otherwise, it selects skip shifting to minimize time loss, thereby optimizing the balance between shift feel quality and response time adaptively.
Solution Approach 2:
The controller changes the shifting control parameters based on the calculated evaluation index. When the index indicates favorable conditions for stepwise shifting, parameters for gradual gear transitions are applied. When conditions favor skip shifting, parameters for direct gear transitions are applied, thus optimizing the trade-off between shift feel quality and response time.
3Speed
If the target gear stage is set to at least two stages lower than the current stage, then the acceleration response is improved, but the shift feel may not be improved without proper selection of shifting method
Solution Approach 1:
The system uses feedback from the accelerator operation evaluation to determine the appropriate shifting method. The controller calculates the evaluation index based on accelerator opening and operating speed, then uses this feedback to select whether to execute skip shifting or stepwise shifting. This feedback mechanism ensures that acceleration response is improved while maintaining reliable acceleration feel by adapting to actual driving conditions.
Solution Approach 2:
The system changes the shifting execution parameters based on the evaluation index feedback. When the index indicates that skip shifting will improve acceleration response without compromising feel, skip shifting parameters are applied. When conditions suggest stepwise shifting is more appropriate, stepwise shifting parameters are applied, thus optimizing both acceleration response and feel.
Data Source
AI summary
A vehicle control system to improve acceleration response and shift feel by executing a power-on downshifting in a suitable manner. An evaluation of a skip shifting and an evaluation of a stepwise shifting are compared to each other when executing the downshifting, based on an evaluation index calculated in advance in accordance with an operating condition of an accelerator. The downshifting operation to be executed is selected from the stepwise shifting and the skip shifting whose evaluation is higher than the other one.