Automatic Transmission Shift Calibration via Gear Ratio Gradient Optimization
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Solution Overview
Problem
Conventional transmission control systems are limited in achieving comprehensive and systematic characterization and parameterization of all feasible shift calibrations, resulting in suboptimal transmission shift quality, vehicle drivability, and fuel economy.
Innovation Solution
A calibration system that models gear shift events by obtaining parameters indicative of clutch interactions and gear ratio gradients, determines shift quality ratings based on vehicle acceleration, and adjusts clutch torque and slip profiles to satisfy quality thresholds, using a neural network-based shift quality rating system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional transmission control systems are used, then the system is simple to implement, but the shift quality and vehicle drivability are suboptimal
Solution Approach 1:
The system performs preliminary characterization and parameterization of all feasible shift calibrations through simulation before actual implementation. By pre-defining gear ratio gradients and clutch interaction profiles that satisfy vehicle acceleration thresholds, the system establishes optimal shift parameters in advance, enabling improved shift quality without increasing runtime control complexity.
Solution Approach 2:
The system systematically varies gear ratio gradient parameters and clutch interaction parameters to identify optimal calibration settings. By changing these parameters within defined constraints and evaluating their impact on vehicle acceleration and shift quality, the system discovers superior calibration configurations that improve shift performance while maintaining control system manageability.
2Reliability
If comprehensive characterization of all feasible shift calibrations is achieved, then shift quality improves, but the calibration process becomes more complex
Solution Approach 1:
The calibration system segments the complex characterization task into distinct simulation components: gear ratio gradient analysis, clutch interaction modeling, vehicle acceleration calculation, and shift quality evaluation. By dividing the comprehensive calibration process into these manageable segments, the system achieves thorough characterization of all feasible calibrations while keeping the overall system complexity tractable through modular architecture.
3Speed
If gear ratio gradient is increased for faster shifts, then shift speed improves, but vehicle jerk increases reducing drivability
Solution Approach 1:
The system incorporates feedback by calculating vehicle acceleration and comparing it against defined thresholds during the simulation process. When gear ratio gradient changes cause excessive vehicle jerk, the feedback mechanism identifies this condition and adjusts the gradient parameters accordingly, enabling the system to achieve fast shifts while maintaining acceptable drivability through iterative optimization.
Data Source
AI summary
Calibration and simulation techniques for modeled gear shift events of an automatic transmission of a vehicle comprise obtaining a set of parameters for a modeled gear shift event of the transmission and, based on the set of parameters, modeling forward/aft vehicle acceleration caused by the modeled gear shift event. A shift quality rating system is the utilized to obtain a shift quality rating of the modeled gear shift event based on at least one of the set of parameters and the modeled forward/aft vehicle acceleration. Finally, the techniques determine whether the determined shift quality rating satisfies a shift quality rating threshold and, when the determined shift quality rating fails to satisfy the shift quality rating threshold, a gear ratio gradient for the modeled gear shift event is adjusted and the process is repeated until the determined shift quality rating satisfies the shift quality rating threshold.