Hybrid Powertrain Torque Control via Feedback and Dynamics

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Solution Overview

Problem

Current hybrid powertrain control systems face challenges in efficiently managing torque inputs from both internal combustion engines and electric machines to optimize fuel economy, emissions, and drivability, particularly in responding to operator torque requests while adhering to maximum and minimum allowable input torques.

Innovation Solution

A control method that determines preferred input torque from the engine based on operator inputs and adjusts engine operation within allowable limits, using a hybrid transmission with electric machines and energy storage devices to manage torque transfer and optimize system efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the control system determines preferred input torque based on operator inputs, then drivability and operator demand satisfaction are improved, but the system may exceed maximum or minimum allowable input torques causing reliability issues

Engineering Contradiction:

ImprovedrivabilityVSAvoidtorque limit compliance

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The control system continuously monitors actual engine torque against maximum and minimum allowable input torques, and adjusts engine torque commands in real-time based on this feedback to ensure compliance with torque limits while maintaining drivability

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts engine torque by modifying combustion timing (spark advance or injection timing) in response to changing torque requirements and constraints, allowing the engine to operate within allowable limits while responding to operator demands

Inventive Principle:

Principle #15Dynamics

2Reliability

If the system controls engine torque within allowable limits, then reliability and component protection are improved, but fuel economy optimization is reduced

Engineering Contradiction:

Improvetorque limit complianceVSAvoidfuel economy

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system changes engine operating parameters including combustion timing and torque magnitude to find optimal operating points that satisfy torque limits while minimizing fuel consumption, adjusting these parameters dynamically based on driving conditions

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The control system predicts upcoming torque requirements and adjusts engine operation in advance to stay within allowable limits while optimizing fuel economy, rather than reacting after constraints are violated

Inventive Principle:

Principle #10Preliminary action

3Speed

If the system responds quickly to operator torque requests, then drivability is improved, but the system may not have time to adjust within allowable torque limits

Engineering Contradiction:

Improvetorque response speedVSAvoidtorque limit compliance

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The control system determines maximum and minimum allowable input torques in advance and uses these pre-calculated constraints to quickly adjust engine torque commands without complex real-time calculations, enabling fast response while ensuring compliance

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses real-time feedback on actual torque and allowable limits to make rapid corrective adjustments to engine torque commands, ensuring compliance is maintained even during transient response to operator inputs

Inventive Principle:

Principle #23Feedback

4Use of energy by moving object

If the hybrid transmission manages torque transfer between engine and electric machines, then system efficiency is improved, but device complexity increases

Engineering Contradiction:

Improvesystem efficiencyVSAvoidcontrol system complexity

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The control system manages multiple functions including torque distribution between engine and electric machines, fuel economy optimization, emissions control, and torque limit compliance using a single integrated control architecture, reducing overall system complexity despite multiple functions

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines control of engine torque, electric machine torque, and transmission operation into a unified control system that optimizes overall hybrid powertrain efficiency while managing complexity through integration rather than separate independent control systems

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS8448731B2Method and apparatus for determination of fast actuating engine torque for a hybrid powertrain system

Publication Date: 2013.05.28 MERCEDES BENZ GROUP AG

AI summary

An engine is coupled to an input member of a hybrid transmission and the hybrid transmission is operative to transfer torque between the input member and a torque machine and an output member to generate an output torque in response to an operator torque request. The torque machine is connected to an energy storage device. A method for controlling the engine includes determining a preferred input torque from the engine to the hybrid transmission based upon operator inputs to an accelerator pedal and a brake pedal, determining maximum and minimum allowable input torques from the engine to the hybrid transmission, controlling the engine at the preferred input torque when the preferred input torque is within the maximum and minimum allowable input torques, and controlling the engine based upon the maximum and minimum allowable input torques when the preferred input torque is outside one of the maximum and minimum allowable input torques.