Automatic Gearbox Control for Acceleration-Based Shift Logic
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Solution Overview
Problem
Current automated gearbox control systems in vehicles fail to ensure minimum acceleration and avoid unnecessary downshifts when maintaining a programmed speed setpoint, especially when dealing with varying road slopes and resistance forces.
Innovation Solution
A method and device for controlling an automated gearbox that determines the gear engagement based on maximum acceleration, current speed, programmed speed setpoint, and requested acceleration value, considering resistance forces and comfort acceleration to ensure comfortable acceleration and maintain the driver's chosen speed setpoint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If gear engagement is controlled using calibrated lookup tables based on speed difference, then unnecessary downgrades are delayed, but minimum acceleration level for speed control functions cannot be ensured
Solution Approach 1:
The patent changes the control parameters from simple speed difference-based lookup tables to a comprehensive set including requested acceleration, maximum acceleration, current speed, and speed setpoint. This allows the system to distinguish between legitimate acceleration needs and normal speed adjustments, resolving the contradiction by enabling accurate differentiation of driver intent while maintaining acceleration guarantees.
Solution Approach 2:
The system performs preliminary calculation of maximum acceleration capability based on resistance forces and powertrain characteristics before determining gear engagement. This advance preparation allows the control system to proactively select appropriate gears that guarantee minimum acceleration levels while avoiding unnecessary downgrades, as the system already knows the vehicle's acceleration potential.
2Device complexity
If empirical calibrated lookup tables are used to minimize unnecessary downgrades, then gear change control is simplified, but both minimum acceleration assurance and unnecessary downgrade prevention fail
Solution Approach 1:
The patent segments the gear control decision into distinct functional components: calculating maximum acceleration from resistance forces and powertrain torque, determining requested acceleration from speed control system parameters, comparing these values to select optimal gear, and executing the gear change. This segmentation maintains relative simplicity while dramatically improving reliability by addressing each factor systematically rather than relying on a single empirical lookup table.
3Stability of the object's composition
If gear engagement is delayed as a function of speed difference, then unnecessary demotions are avoided, but acceleration performance for speed control functions deteriorates
Solution Approach 1:
The system implements feedback by continuously monitoring the relationship between requested acceleration (from speed control system) and maximum acceleration (from powertrain capability and resistance forces). This feedback loop allows the system to maintain gear stability when acceleration demands are normal while immediately responding when acceleration performance becomes insufficient, thus achieving both stability and productivity.
Data Source
Figure 1~2
AI summary
The invention relates to a method that is dedicated to the control of an automatic gearbox (BV) of a vehicle (V) provided with a power train (GM) and a speed control system (SC) having a programmable set speed. Said method involves determining the gear to be engaged in the gearbox (BV) depending on a maximum acceleration of the vehicle (V) for the gear that is currently engaged in the gearbox (BV), the current speed of the vehicle (V), a programmed set speed of the system (SC), and an acceleration value requested by the system (SC).