Hybrid Drivetrain Shift Control Interpolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing shift control methods for hybrid drivetrains with internal combustion engines and electric machines require numerous shift characteristic curves for various driving conditions, leading to complex selection procedures and inefficient adaptation to different operating modes, particularly in pure electric operation where the electric machine's behavior differs from the internal combustion engine's.
Innovation Solution
A method that determines valid shift characteristic curves by interpolating between eco-shift and sport-shift limit curves, using a dynamics factor derived from driving and operating parameters, with a limited interpolation range in pure electric operation to adapt to the electric machine's behavior, ensuring optimal fuel efficiency and driving dynamics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple shift characteristic curves are stored for various driving conditions, then the adaptability to different driving situations is improved, but the device complexity and selection procedure complexity increase
Solution Approach 1:
The patent segments the continuous range of driving conditions into discrete categories represented by limit shift characteristic curves (e.g., sport-oriented, eco-oriented, comfort-oriented). Instead of storing and selecting from numerous individual curves for every possible condition, the system stores a limited set of extreme/limit curves and segments the adaptation task into interpolating between these predefined segments based on driving situation parameters.
Solution Approach 2:
The patent changes the parameter representation from storing complete shift characteristic curves for each condition to storing only the limit curves and using interpolation parameters (weights, mixing factors) to generate intermediate curves. This parameter transformation reduces the data storage requirement and simplifies the selection process by converting a complex curve selection problem into a simpler parameter adjustment problem.
2Device complexity
If limit shift characteristic curves are used with interpolation, then the device complexity is reduced, but the manufacturing precision and accuracy of shift control may be compromised
Solution Approach 1:
The patent introduces an intermediary mechanism (interpolation algorithm) that generates intermediate shift characteristic curves between the stored limit curves. This intermediary process allows the system to achieve high precision shift control for any driving condition within the range covered by the limit curves, without needing to store every possible individual curve. The interpolation acts as a mediator that preserves accuracy while reducing complexity.
Solution Approach 2:
The patent performs preliminary action by pre-calculating and storing only the extreme/limit shift characteristic curves that define the boundaries of the driving condition space. These pre-computed limit curves serve as the foundation for generating all intermediate curves through interpolation, eliminating the need to pre-store and pre-process numerous individual curves for every possible driving scenario.
3Use of energy by moving object
If shift control is optimized for internal combustion engine operation, then fuel efficiency is improved, but the adaptability to electric machine operation is reduced
Solution Approach 1:
The patent creates a universal shift control system that functions optimally across multiple operating modes (pure internal combustion engine, pure electric machine, and mixed operation). By using interpolation between limit curves that represent different operating characteristics, the system achieves multi-functionality, adapting to fuel efficiency requirements in ICE mode while also accommodating the different behavior patterns of electric machine operation and mixed-mode transitions.
Solution Approach 2:
The patent introduces dynamic adaptability by allowing the shift characteristic curves to change continuously based on the current operating mode and driving situation. The interpolation mechanism dynamically adjusts the shift points and characteristics in real-time according to the operating mode (ICE, electric, or mixed), enabling the system to optimize fuel consumption in ICE mode while seamlessly adapting to the instantaneous torque and power characteristics of electric machine operation.
Data Source
AI summary
A method for a shift control of a drivetrain of a motor vehicle includes providing the drivetrain of the motor vehicle as a hybrid drivetrain wherein an electric machine is connected to an input shaft of an automated stepped shift transmission and wherein an internal combustion engine is connected to the input shaft of the automated stepped shift transmission via a decoupling clutch. Currently valid shift characteristic curves used for triggering respective shifts of the automated stepped shift transmission are determined respectively in dependence of current driving and operating parameters by performing an interpolation between a first limit shift characteristic curve for a first driving characteristic and a second limit shift characteristic curve for a second driving characteristic wherein the respective limit shift characteristic curves are identical in all operating modes, however a permissible interpolation range in a purely electric operation is limited.