Clutch Actuation Motor Torque Control for Power Efficiency

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Solution Overview

Problem

All-wheel drive vehicles have lower fuel economy due to additional power required for their complex drivelines, and current actuation systems for active differentials apply constant electrical current regardless of force needed, leading to inefficiency.

Innovation Solution

A clutch actuation system that estimates and applies the precise force needed to engage or disengage the clutch pack using a control unit, actuation motor, and force translational device, modeling frictional characteristics and adjusting torque to optimize power consumption based on rotational position and motor torque.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If constant electrical current is applied to the actuation motor, then the clutch pack can be engaged or disengaged, but power consumption increases due to applying the same force in all situations

Engineering Contradiction:
Improvepower consumptionVSAvoidclutch engagement reliability
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The system dynamically adjusts the electrical current applied to the actuation motor based on the actual force needed to engage or disengage the clutch pack. The control unit modifies motor current in real-time according to motor position and operational conditions, replacing the static constant current approach with a dynamic adaptive control strategy that optimizes power consumption while ensuring reliable clutch actuation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system implements feedback control by monitoring the motor position and using this information to adjust the electrical current applied to the actuation motor. The control unit receives feedback about the clutch pack engagement state and motor position, then modifies the actuation force accordingly, creating a closed-loop control system that reduces power consumption while maintaining engagement reliability.

Inventive Principle:
Principle #23Feedback

2Reliability

If the actuation system applies maximum force to ensure clutch engagement, then reliability is improved, but power consumption increases

Engineering Contradiction:
Improveclutch engagement reliabilityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The system changes the electrical current parameter applied to the actuation motor based on motor position and operational conditions. Instead of applying maximum current constantly, the control unit adjusts the current parameter dynamically - applying higher current only when and where needed for reliable engagement, and reducing current during other phases, thereby optimizing the balance between engagement reliability and power consumption.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If the clutch actuation system accounts for wear and operational conditions, then precision of force estimation is improved, but system complexity increases

Engineering Contradiction:
Improveforce estimation precisionVSAvoidcontrol system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system replaces complex mechanical force sensing mechanisms with an electronic control approach that estimates force based on motor position and operational parameters. The control unit calculates the required actuation force using software algorithms that account for wear and conditions, substituting physical sensors and complex mechanical feedback systems with computational methods that achieve similar precision with reduced hardware complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

This approach reduces power consumption and maintains output torque levels, improving fuel efficiency by accurately estimating and applying the necessary force to the clutch pack, accounting for wear and operational conditions.

Implementation Method 1

An electromagnetic actuator includes an axially moveable armature for applying an application force to the clutch

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

Through the force translational device, force applied by the actuation motor is applied to the clutch pack

Methodology Applied
Scientific EffectMechanical advantage: Mechanical Advantage

Implementation Method 3

modeling frictional characteristics associated with said clamping and release of said clutch pack

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3221609B1A method to control clutch force in a clutch pack
Publication Date: 2021.07.07 DANA AUTOMOTIVE SYST GRP LLC
  • EP3221609B1 patent drawingFigure 1~2
  • EP3221609B1 patent drawingFigure 3~4
  • EP3221609B1 patent drawingFigure 5~8

AI summary

A method to estimate force in a clutch pack includes engaging an actuation motor to produce a motor torque to apply a set point force to a clutch pack. The amount of motor torque being applied to the clutch pack at the set point force is monitored. The amount of motor torque being applied to the clutch between a clutch clamping curve and a clutch releasing curve at the set point force is maintained.