Uphill Gear Downshift Control to Prevent Stall and Rollback
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Solution Overview
Problem
Conventional vehicle control systems struggle with downshifting gears in uphill slopes, leading to potential engine stalling and uncontrollable vehicle movement due to insufficient engine power and increased risk of rolling backwards, especially on steep inclines with heavy loads.
Innovation Solution
A method and control arrangement that simulates speed profiles for downshifting in an uphill slope, determining if a downshift can be performed safely by comparing driving resistance forces with traction forces, activating the brake if necessary, shifting to a start gear, and synchronizing clutch and brake deactivation to maintain control and prevent engine stalling or rollback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a downshift is performed to maintain engine power in an uphill slope, then engine power availability is improved, but vehicle speed may drop to zero or below causing engine stalling or rollback
Solution Approach 1:
The control arrangement performs a preliminary simulation of the speed profile before actually executing the downshift. By predicting the minimal speed that will occur after downshift and comparing it with zero, the system determines in advance whether the downshift is safe, preventing engine stalling or rollback before they can occur.
Solution Approach 2:
The control arrangement takes preliminary counter-actions by opening the clutch and activating the brake before the downshift if the simulation predicts unsafe conditions. This prevents the harmful effect (vehicle speed dropping to zero or below) from occurring in the first place.
2Use of energy by moving object
If conventional gearbox control systems are used for automatic gear shifting, then fuel consumption is optimized, but the system cannot adequately handle uphill slope conditions leading to engine stalling
Solution Approach 1:
The control arrangement incorporates feedback by simulating the speed profile based on current vehicle conditions (including uphill slope) and using this information to adjust gear shifting decisions. The system continuously monitors and predicts vehicle behavior to make informed control decisions that prevent engine stalling while maintaining fuel efficiency.
Solution Approach 2:
The control arrangement dynamically adapts gear shifting decisions based on real-time simulation of vehicle conditions. Instead of using fixed fuel-optimal shifting patterns, the system adjusts gear selection and timing based on predicted vehicle speed profiles and uphill slope conditions, ensuring reliable engine operation while maintaining energy efficiency.
Data Source
AI summary
A method in a control arrangement of a vehicle and a control arrangement for a vehicle for downshifting gears in an uphill slope are presented. The method comprises, when the vehicle is travelling in an uphill slope using an initial gear of the vehicle's automated manual transmission gearbox: simulating at least one speed profile for a downshift to, and a usage of, at least one gear; determining that a minimal speed of each one of the at least one simulated speed profile has a value indicating that the actual speed of the vehicle will be less than or equal to zero in the uphill slope; opening a clutch before is reduced to a value less than zero; activating at least one vehicle brake; shifting vehicle's automated manual transmission gearbox to a start gear; closing the clutch; and deactivating the at least one vehicle brake.