Clutch Torque Control for AMT Micro-Slip Transitions

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Solution Overview

Problem

In vehicles equipped with dry clutches, such as Automated Manual Transmission (AMT) or Dual Clutch Transmission (DCT), existing methods for learning clutch transfer torque characteristics result in power loss during micro-slip conditions, leading to reduced fuel efficiency and potential clutch reengagement collisions when transitioning from full-lock to micro-slip control.

Innovation Solution

A method involving a controller that determines slip entry, monitors clutch release, adjusts feedback torque using PID control components, and recalculates clutch control torque to maintain proper micro-slip status, preventing unnecessary clutch release and fuel-cut stops.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the controller enters micro-slip control to learn clutch transfer torque characteristics, then the clutch characteristic learning accuracy is improved, but power loss occurs and fuel efficiency deteriorates

Engineering Contradiction:

Improveclutch transfer torque characteristic learning accuracyVSAvoidpower loss

Core Design Contradiction:

Measurement precisionVSLoss of energy

Solution Approach 1:

The controller performs preliminary determination of slip entry conditions before initiating micro-slip control. By checking whether the vehicle is in a suitable state (no gear shifting, stable operation) before entering micro-slip mode, the system prepares in advance to minimize unnecessary power loss while ensuring accurate learning conditions are met.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Instead of maintaining continuous micro-slip control for learning, the controller applies partial action by entering micro-slip mode only when specific conditions are met (determined by slip entry determination). This partial engagement allows sufficient data collection for accurate clutch characteristic learning while avoiding excessive power loss during unnecessary micro-slip operations.

Inventive Principle:

Principle #16Partial or excessive action

2Adaptability or versatility

If the controller transitions from full-lock control to micro-slip control when the driver releases the accelerator pedal, then the clutch characteristic adaptation is improved, but clutch release occurs leading to fuel-cut stop and reduced fuel efficiency

Engineering Contradiction:

Improveclutch characteristic adaptationVSAvoidfuel efficiency

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The controller applies preliminary anti-action by detecting the tendency toward clutch release through monitoring the proportional control component before actual release occurs. When the proportional control component exceeds the reference value for a predetermined time, the controller preemptively adjusts the clutch control torque to counteract the release tendency, preventing fuel-cut stop and maintaining fuel efficiency.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The system continuously monitors the proportional control component as feedback regarding clutch release tendency. This feedback mechanism allows the controller to detect early signs of clutch release during the transition from full-lock to micro-slip control and respond by adjusting the clutch control torque to maintain stable engagement and prevent fuel-cut stops.

Inventive Principle:

Principle #23Feedback

3Adaptability or versatility

If the controller transitions from full-lock control to micro-slip control, then the clutch learning capability is improved, but clutch reengagement collision occurs

Engineering Contradiction:

Improveclutch learning capabilityVSAvoidclutch reengagement safety

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The controller performs preliminary monitoring of clutch release status before completing the transition to micro-slip control. By detecting clutch release tendency in advance through the proportional control component monitoring, the system prepares to adjust control torque to prevent excessive release and subsequent reengagement collisions, ensuring safe clutch operation during learning transitions.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system provides beforehand cushioning by monitoring clutch release tendency and preemptively adjusting the clutch control torque to prevent excessive clutch release. This cushioning effect ensures that even if clutch release begins, the control torque adjustment prevents complete disengagement and potential reengagement collisions, protecting the clutch system during learning transitions.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentUS10274028B2Method for controlling clutch for vehicle

Publication Date: 2019.04.30 HYUNDAI MOTOR CO LTD

AI summary

The present disclosure is configured to include a slip entry determining step of determining, by a controller, whether a driver in a full-lock control releases an accelerator pedal to thereby enter into a micro-slip control; a monitoring step of monitoring, by the controller, whether the release of the clutch occurs, in case of entering into the micro-slip control as a result of performing the slip entry determining step; a control amount adjusting step of resetting a feedback amount of a clutch control torque in the case that the release of the clutch occurs; and a clutch control step of controlling the clutch according to the clutch control torque as reset by the control amount adjusting step to thereby prevent or minimize the release of the clutch.