Vehicle Shift Control for Uphill Downshift Stall Prevention
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Solution Overview
Problem
Vehicles temporarily stall when downshifting on uphill sections, leading to prolonged recovery times.
Innovation Solution
A vehicle control device that determines a forward travel section with a different road gradient, selects a forward gear stage lower by two or more stages than the current gear stage, and controls the shift to prevent downshifting within a predetermined range from the start position of the forward travel section, maintaining the current gear stage if the calculated stall amount is below a certain threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If downshift is performed while travelling the uphill section, then the vehicle can maintain speed on the uphill section, but the vehicle temporarily stalls and it takes time for recovering the speed
Solution Approach 1:
The system performs preliminary determination of the forward travel section's road gradient and calculates the appropriate forward gear stage before the vehicle actually enters the uphill section. By preparing the gear shift decision in advance based on predicted road conditions, the system can execute the downshift at the optimal moment, preventing speed loss and avoiding stalls while minimizing recovery time.
2Adaptability or versatility
If downshift is performed from current gear stage to forward gear stage lower by two or more stages, then the vehicle can adapt to the forward travel section's road gradient, but the vehicle experiences temporary stall during the shift
Solution Approach 1:
The system determines the forward gear stage in advance based on the road gradient of the forward travel section. By calculating the appropriate target gear stage before the actual shift is needed, the system can prepare for the downshift and execute it more smoothly, reducing the likelihood of temporary stalls and improving overall vehicle stability during the transition.
Data Source
AI summary
A vehicle control device includes: a travel section determination unit configured to determine a forward travel section that is a travel section having a different road gradient from a current travel section in which a vehicle is currently traveling and that is ahead in a travel direction of the vehicle; a forward gear stage selection unit configured to select a forward gear stage which is a gear stage of the vehicle in the forward travel section; and a shift control unit configured to, in a case where the selected forward gear stage is lower by two or more stages than the current gear stage which is a gear stage of the vehicle in the current travel section and when the vehicle is positioned within a predetermined range from a start position of the forward travel section, perform downshift from the current gear stage to the forward gear stage.