Hybrid Transmission Torque Control via Linear Quadratic Constraints

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Solution Overview

Problem

Current hybrid transmission control systems face challenges in efficiently managing torque distribution between internal combustion engines and electric machines, particularly in determining optimal output torque while adhering to linear and quadratic constraints, which affects fuel efficiency and vehicle performance.

Innovation Solution

The method involves determining preferred output torque by solving relationships between motor torque constraints, clutch reactive torque constraints, and power constraints from the energy storage device, allowing for simultaneous operation within linear and quadratic output torque limits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the control system determines optimal output torque by solving simultaneous linear and quadratic relationships, then torque distribution precision is improved, but computational complexity increases

Engineering Contradiction:
Improvetorque distribution precisionVSAvoidcontrol system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The control method segments the torque optimization problem into distinct linear and quadratic constraint relationships. Linear relationships handle motor torque constraints and clutch reactive torque, while quadratic relationships handle power constraints from the energy storage device. This segmentation allows the complex optimization problem to be solved through systematic mathematical relationships rather than requiring a monolithic complex control system.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the system operates within multiple simultaneous constraints (linear and quadratic), then operational reliability is improved, but control difficulty increases

Engineering Contradiction:
Improveoperational reliabilityVSAvoidcontrol difficulty
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The control system continuously monitors operating conditions and adjusts torque distribution by solving the linear and quadratic relationships in real-time. The system uses feedback from the energy storage device power constraints, motor torque constraints, and clutch reactive torque constraints to dynamically determine the optimal output torque that satisfies all constraints simultaneously, ensuring reliable operation while adapting to changing conditions.

Inventive Principle:
Principle #23Feedback

3Use of energy by moving object

If the control system simultaneously solves linear and quadratic torque relationships, then fuel efficiency is improved, but processing time increases

Engineering Contradiction:
Improvefuel efficiencyVSAvoidprocessing time
Core Design Contradiction:
Use of energy by moving objectVSLoss of time

Solution Approach 1:

The control method establishes the linear and quadratic relationship models in advance, defining how motor torque constraints, clutch reactive torque constraints, and power constraints from the energy storage device interact. By having these mathematical relationships pre-defined, the system can quickly solve for optimal torque distribution when operating conditions change, reducing real-time processing time while maintaining fuel efficiency optimization.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2070794B1Method and apparatus to determine a preferred output torque for operating a hybrid transmission in a continuously variable mode
Publication Date: 2013.09.11 GM GLOBAL TECHNOLOGY OPERATIONS LLC
  • EP2070794B1 patent drawingFigure 1
  • EP2070794B1 patent drawingFigure 2
  • EP2070794B1 patent drawingFigure 3

AI summary

A hybrid transmission includes a torque machine and an energy storage device connected thereto. The hybrid transmission is operative to transfer power between an input member and an output member and the torque machine in a continuously variable operating range state. A method for controlling the hybrid transmission includes determining a preferred output torque, determining a relationship between power from the energy storage device and an output torque of the transmission, determining power constraints from the energy storage device, determining motor torque constraints for the torque machine, determining linear torque constraints to the output torque based upon the motor torque constraints for the torque machine, determining quadratic output torque constraints based upon the power constraints from the energy storage device and the relationship between the power from the energy storage device and the output torque of the transmission device, and determining an output torque to the output member responsive to the preferred output torque and achievable based upon the linear output torque constraints and the quadratic output torque constraints.