Electro-Mechanical Transmission Torque Pulse Cancellation

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Solution Overview

Problem

Powertrain systems experience objectionable vibrations and noise due to compression torque pulses during autostop and autostart operations, affecting vehicle operation and passenger comfort.

Innovation Solution

A method for controlling an electro-mechanical transmission that involves determining engine pulse torque and calculating motor torque pulse commands using transfer functions to counteract the engine pulse torque, thereby reducing vibrations and noise by controlling the torque machines.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If autostop and autostart operations are implemented to improve fuel economy, then fuel consumption is reduced, but compression torque pulses generate objectionable vibrations and noise

Engineering Contradiction:

Improvefuel economyVSAvoidvibrations and noise

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The control system calculates compression torque pulses before they occur and applies counteracting motor torque commands to cancel them out. The transfer functions predict the magnitude and timing of compression pulses, and the motor torque is applied in advance to prevent the pulses from causing vibrations and noise, thus eliminating the harmful effects before they manifest.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The harmful compression torque pulses are converted into a beneficial control signal. The control system uses the predicted compression pulse information to generate motor torque commands that not only cancel the harmful vibrations but also smooth the overall torque delivery, transforming a problematic phenomenon into an opportunity for improved torque control and passenger comfort.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Device complexity

If compression torque pulses are allowed to transmit to the transmission, then engine operation is simple, but vibrations reach the vehicle operator at resonant frequencies

Engineering Contradiction:

Improveengine control complexityVSAvoidvibrations at resonant frequencies

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The control system employs a feedback mechanism where the predicted compression torque pulses are continuously monitored and used to adjust motor torque commands in real-time. The transfer functions provide a dynamic model that feeds back the relationship between compression pulses and required compensation torque, enabling continuous adjustment to maintain smooth operation despite varying engine conditions.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The motor acts as an intermediary between the engine and the transmission. Instead of allowing compression pulses to directly transmit to the transmission and cause vibrations, the motor serves as a buffer that absorbs and compensates for the pulse torques, isolating the harmful effects from the drivetrain and passenger compartment.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If motor torque pulse commands are calculated using transfer functions to cancel engine pulse torque, then vibrations and noise are reduced, but control system complexity increases

Engineering Contradiction:

Improvevibrations and noiseVSAvoidcontrol system complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The control system performs preliminary calculations of the required motor torque commands before the compression pulses occur. By using the transfer functions to predict the necessary compensation torque in advance and preparing the motor torque commands beforehand, the system eliminates vibrations and noise without requiring complex real-time adjustments during the actual pulse events.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS8849460B2Method and apparatus for determining engine pulse cancellation torque

Publication Date: 2014.09.30 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

A method for controlling operation of an electro-mechanical transmission configured to transfer torque among an input member, a plurality of torque machines and an output member includes determining an engine pulse torque, calculating a first motor torque pulse command based upon a first transfer function between the engine pulse torque and a torque command for a first torque machine and the engine pulse torque, calculating a second motor torque pulse command based upon a second transfer function between the engine pulse torque and a torque command for a second torque machine and the engine pulse torque, and controlling the first torque machine in response to the first motor torque pulse command and controlling the second torque machine in response to the second motor torque pulse command.