Lockup Clutch Torque Transition Control

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Solution Overview

Problem

Existing lockup clutch control systems experience shocks during transitions from driven to driving states and vice versa due to rapid changes in target clutch torque capacity, and existing solutions are ineffective for all scenarios, particularly when transitioning from acceleration slip control to deceleration slip control.

Innovation Solution

A control apparatus for a lockup clutch that includes an electronic control unit to calculate and manage target clutch torque capacities for both driven and driving states, seamlessly transitioning between them based on accelerator state changes, ensuring coincident torque capacities to prevent shocks and optimize transitions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the target clutch torque capacity is immediately changed over at the time of driving/driven changeover, then the response speed of the control system is improved, but a shock occurs due to rapid change in target clutch torque capacity

Engineering Contradiction:
Improveresponse speed of target clutch torque capacity changeoverVSAvoidshock at driving/driven transition
Core Design Contradiction:
SpeedVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary comparison between driven target clutch torque capacity and driving target clutch torque capacity before executing the changeover. By checking whether the values coincide with each other in advance, the system ensures that the changeover occurs only when appropriate, preventing shocks while maintaining responsive control.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system continuously monitors and compares the driven target clutch torque capacity and driving target clutch torque capacity, using this feedback information to determine the optimal timing for changeover. This feedback mechanism ensures that changeover occurs only when the torque capacities coincide, eliminating shocks while maintaining fast response.

Inventive Principle:
Principle #23Feedback

2Productivity

If the target clutch torque capacity is changed over rapidly during accelerator state transition, then the control efficiency is improved, but the transition smoothness deteriorates due to shock occurrence

Engineering Contradiction:
Improvecontrol efficiency during state transitionVSAvoidtransition smoothness between driven and driving states
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The system performs preliminary comparison of torque capacities before changeover execution, ensuring that the transition occurs only when the driven and driving target clutch torque capacities coincide. This preliminary check maintains control efficiency while ensuring smooth transitions without shock.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system changes the target clutch torque capacity parameter only when specific conditions are met (when driven and driving target values coincide). This conditional parameter change approach maintains both control efficiency and transition smoothness by avoiding abrupt changes that would cause shock.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If existing lockup clutch control methods are applied to all transition scenarios, then the device complexity is reduced, but the adaptability to different operating conditions deteriorates

Engineering Contradiction:
Improvecontrol system complexityVSAvoidadaptability to different accelerator state transitions
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The control system uses a universal comparison mechanism that works for all transition scenarios (accelerator ON to OFF, and accelerator OFF to ON). By making the control logic universal rather than scenario-specific, the system maintains low complexity while achieving high adaptability to different operating conditions.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system adapts to different operating conditions by dynamically changing the target clutch torque capacity parameter based on accelerator state transitions. The same comparison-based control logic handles all scenarios, providing both simplicity and adaptability through parameter adjustment rather than complex scenario-specific logic.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3244098B1Control apparatus for lockup clutch
Publication Date: 2020.04.08 TOYOTA JIDOSHA KK
  • EP3244098B1 patent drawingFigure 1
  • EP3244098B1 patent drawingFigure 2
  • EP3244098B1 patent drawingFigure 3

AI summary

A control apparatus for a lockup clutch is provided. The control apparatus for the lockup clutch includes an electronic control unit that is configured to: calculate a driven target clutch torque capacity and a driving target clutch torque capacity; set a target clutch torque of the lockup clutch and control the lockup clutch, based on the driven target clutch torque capacity and the driving target clutch torque capacity; and change over the target clutch torque capacity from the driven target clutch torque capacity to the driving target clutch torque capacity when the driven target clutch torque capacity and the driving target clutch torque capacity coincide with each other after an operation state of an accelerator of the vehicle changes over from an accelerator OFF state to an accelerator ON state.