AMT Gear Selection for Heavy Uphill Driving
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Solution Overview
Problem
Heavy vehicles equipped with Automatic Mechanical Transmissions (AMT) face difficulties in selecting optimal gear ratios during heavy uphill drives, leading to increased fuel consumption, decreased average speed, and a high risk of wheel slip, which can result in vehicle stoppage and difficulty in restarting.
Innovation Solution
A method for automatically identifying heavy uphill drive conditions and selecting the highest possible gear with the lowest gear ratio that allows the vehicle to maintain constant speed or accelerate, with further downshifts adapted to ensure no lower gear is engaged than the target gear, using a control unit that processes signals from vehicle speed, engine rotational speed, throttle displacement, and other parameters to optimize gear selection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the AMT-system selects a high gear ratio based on predetermined gear shift maps during uphill driving, then the vehicle speed decreases and fuel consumption increases, but the system avoids excessive downshifts that could cause wheel slip
Solution Approach 1:
The control unit predicts future gear shift steps and determines a gear shifting sequence in advance, rather than reacting to current conditions only. This preliminary planning allows the system to select optimal gear ratios that maintain vehicle speed while avoiding excessive downshifts that would increase fuel consumption
Solution Approach 2:
The system dynamically adapts the gear selection strategy based on detected uphill conditions. When an uphill drive condition is detected, the control unit modifies the gear shifting behavior to prevent selecting gear ratios that would cause the vehicle to slow down excessively or stop, thereby maintaining better fuel efficiency
2Speed
If the AMT-system shifts down to lower gear ratios during heavy uphill driving, then the vehicle can maintain speed and acceleration capability, but the risk of wheel slip increases due to high output torque
Solution Approach 1:
The control unit predicts the gear shifting sequence in advance and identifies a target gear that balances speed maintenance with slip prevention. By planning ahead, the system avoids abrupt downshifts to very low gears that would generate excessive torque and cause wheel slip
Solution Approach 2:
The system continuously monitors driving conditions and uses this feedback to adjust gear selection. When uphill conditions are detected, the control unit modifies gear ratio selection to maintain vehicle speed while keeping output torque within safe limits to prevent wheel slip
3Ease of operation
If the AMT-system uses predetermined gear shift maps for gear selection, then the system operation is simple and reliable, but it cannot adapt optimally to heavy uphill drive conditions
Solution Approach 1:
The system dynamically switches between standard gear shift map operation and special uphill driving mode. When normal conditions prevail, the simple predetermined maps are used. When uphill conditions are detected, the system adapts by predicting gear sequences and selecting target gears optimized for uphill performance
Solution Approach 2:
The control unit automatically detects uphill drive conditions and adjusts gear selection strategy without driver intervention. The system monitors parameters such as accelerator pedal position, engine speed, and vehicle speed to autonomously determine when to apply the uphill-optimized gear shifting logic
Data Source
AI summary
A method for gear selection during driving of a vehicle in a heavy uphill drive condition is provided, the vehicle including an engine, an automated mechanical transmission, a clutch, a control unit for receiving input signals including signals indicative of vehicle speed, engaged ratio of the transmission, rotational speed of the engine, rotational speed of a input shaft and displacement of a throttle control for engine torque request, and for processing the signals in accordance with programmed logic rules to issue command output signals to the engine, to the transmission and to said clutch. When sensing a heavy uphill drive condition a target gear is determined for the uphill drive condition, the target gear being the highest possible gear with lowest possible gear ratio where the vehicle, in view of at least current circumstances, will be at least theoretically able to hold a constant vehicle speed or accelerate at least slightly, and where further selection of downshifts will be adapted so that no lower gear than the target gear will be selected and engaged.