Hybrid Powertrain Torque Transition Noise Control

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Solution Overview

Problem

Hybrid transmissions experience audible noise and reduced gear durability due to excessive lash during torque transitions, particularly when electric motors reverse torque direction, leading to objectionable noise and potential torque transfer delays.

Innovation Solution

A noise reduction control scheme is implemented in a hybrid powertrain system by determining a transition window for torque output of electric motors and executing a noise reduction control scheme, which involves decoupling the electric motor from the transmission during this window to reduce noise through clutch deactivation or building a torque reserve to quickly reverse gear interactions, thereby minimizing lash-related noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If electric motors reverse torque direction during operation, then torque flexibility and powertrain adaptability are improved, but audible noise and gear durability are worsened due to lash in meshed gears

Engineering Contradiction:

Improvetorque direction reversal capabilityVSAvoidaudible noise and gear durability

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The control system executes preliminary actions before torque reversal by identifying a transition window when motor torque approaches zero. During this window, the system proactively manages gear lash by controlling torque transfer timing, preventing the sudden impact that causes noise and durability issues while enabling smooth torque direction reversal

Inventive Principle:

Principle #10Preliminary action

2Object-affected harmful factors

If clutch deactivation is used to reduce noise during torque transitions, then audible noise is reduced, but torque transfer delays may occur

Engineering Contradiction:

Improveaudible noiseVSAvoidtorque transfer delay

Core Design Contradiction:

Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The system dynamically adjusts clutch engagement timing based on real-time motor torque conditions. By monitoring when motor torque is near zero (transition window), the control system optimizes clutch deactivation and reactivation timing to minimize noise while maintaining efficient torque transfer, adapting the control strategy to the instantaneous operational state

Inventive Principle:

Principle #15Dynamics

3Reliability

If torque reserve is built up to quickly reverse gear interactions, then gear durability is improved, but energy efficiency may be reduced

Engineering Contradiction:

Improvegear durabilityVSAvoidenergy efficiency

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The control system changes operational parameters by monitoring motor torque levels and identifying transition windows. By executing torque reversal during these specific parameter conditions (when torque is near zero), the system reduces the energy required for gear lash management while protecting gear durability, optimizing the balance between reliability and energy efficiency

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS8645013B2Method and apparatus for driveline noise control in a hybrid powertrain

Publication Date: 2014.02.04 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

A hybrid powertrain includes an engine and electric motors configured to transfer torque through a transmission. A method for controlling the hybrid powertrain includes determining a transition window associated with torque output of one of the electric motors coupled to an element of the transmission. A noise reduction control scheme is executed when the torque output of the one of the electric motors coupled to the element of the transmission is within the transition window.