Powertrain Torque Pulse Cancellation via Motor Control

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Solution Overview

Problem

Powertrain systems experience vibration and noise due to compression torque pulses generated during engine auto-start and auto-stop operations, which existing control systems fail to effectively mitigate.

Innovation Solution

A powertrain assembly with a transmission, engine, and motor/generators connected to a controller that calculates and executes motor torque pulse commands to counteract engine pulse torque, using predetermined moment of inertia ratios and gear factors to minimize torque disturbances, thereby reducing vibration and noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If motor torque pulse commands are calculated and executed to counteract engine pulse torque, then vibration and noise are reduced, but device complexity increases

Engineering Contradiction:

Improvevibration and noiseVSAvoidcontrol system complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The controller calculates motor torque pulse commands in advance based on predicted engine pulse torque characteristics before the pulse occurs. This preliminary calculation allows the motor/generators to be ready to counteract the pulse torque immediately when it occurs, reducing vibration and noise without requiring complex real-time sensing and adjustment mechanisms

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The control system uses feedback from engine operating conditions (speed, load, temperature) to continuously adjust the motor torque pulse commands. The controller monitors actual engine pulse torque and modifies the counteracting torque commands accordingly, ensuring effective vibration and noise reduction while maintaining manageable system complexity through adaptive control

Inventive Principle:

Principle #23Feedback

2Object-affected harmful factors

If motor/generators are used to cancel engine pulse torque, then compression torque pulse effects are mitigated, but use of energy increases

Engineering Contradiction:

Improvecompression torque pulse effectsVSAvoidenergy consumption

Core Design Contradiction:

Object-affected harmful factorsVSUse of energy by moving object

Solution Approach 1:

The motor/generators apply torque pulse commands only during specific compression pulses rather than continuously operating. This partial action approach mitigates the harmful compression torque pulse effects while minimizing energy consumption by activating the motor/generators only when needed for pulse cancellation, rather than maintaining constant operation

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The system recovers kinetic energy from the motor/generators during deceleration phases and uses it during acceleration phases for pulse cancellation. This energy recovery mechanism reduces the net energy consumption while still providing the necessary torque pulses to counteract compression torque effects

Inventive Principle:

Principle #34Discarding and recovering

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution effectively cancels engine pulse torque, eliminating the need for damper lockup clutches and reducing noise by ensuring zero rotational speed change in the output member and matching input and engine speed changes, thus improving the operational efficiency and reducing noise.

Implementation Method 1

A first motor/generator is operatively connected to the transmission and has a predetermined first moment of inertia (IA). A second motor/generator is operatively connected to the transmission and has a predetermined second moment of inertia (IB).

Methodology Applied

Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 2

A transmission having at least one planetary gear set

Methodology Applied

Scientific EffectMechanical advantage: Mechanical Advantage

Implementation Method 3

The first motor torque pulse command (TA) is calculated for the first motor/generator as a product of a first gear factor (GA), the engine pulse torque (TP) and a first ratio (IA/IE) of a predetermined first moment of inertia (IA) for the first motor/generator and a predetermined engine moment of inertia (IE)

Methodology Applied

Scientific EffectMoment of inertia: Moment of Inertia

Data Source

PatentUS9873421B2Control of engine pulse torque cancellation commands

Publication Date: 2018.01.23 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

A powertrain assembly includes a transmission, an engine, first and second motor/generators and a controller. The controller includes a processor and memory on which is recorded instructions for executing a method for controlling engine pulse torque cancellation commands. The controller is programmed to determine an engine pulse torque (TP). The controller is programmed to calculate a first motor torque pulse command (TA) for the first motor/generator as a product of a first gear factor (G1), the engine pulse torque (TP) and a first ratio (IA/IE) of a predetermined first moment of inertia (IA) for the first motor/generator and a predetermined engine moment of inertia (IE). Similarly, the controller is programmed to calculate a second motor torque pulse command (TB) for the second motor/generator. The controller is programmed to control the first and second motor/generators in response to the first and second motor torque pulse commands, respectively.