Lock-up Clutch Control Device Engine Racing Suppression

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Solution Overview

Problem

Conventional lock-up clutch control devices for vehicles experience engine racing due to excessive engine torque when engaging the lock-up clutch at starting, as the lock-up command pressure delay leads to a lack of lock-up capacity generation.

Innovation Solution

A lock-up clutch control device that delays the rise in lock-up command pressure when the source pressure of actual lock-up oil pressure is rising, and executes a torque reduction in the engine during this delay to suppress engine racing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the lock-up command pressure is delayed when the line pressure is rising, then shock is suppressed, but engine racing occurs due to excessive engine torque

Engineering Contradiction:
Improvelock-up oil pressure stabilityVSAvoidengine racing
Core Design Contradiction:
Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The invention applies preliminary anti-action by detecting the rising rate of line pressure in advance and proactively reducing engine torque before engine racing occurs. The ECU calculates the rising rate of line pressure and, when it exceeds a threshold, immediately reduces engine torque output to prevent the harmful effect of engine racing during lock-up clutch engagement.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The invention implements feedback control by continuously monitoring the line pressure rising rate and adjusting engine torque accordingly. The ECU calculates the rising rate of line pressure in real-time and uses this feedback information to dynamically control engine torque, reducing it when the rising rate is high and restoring it when the rising rate decreases, thereby preventing engine racing while maintaining pressure stability.

Inventive Principle:
Principle #23Feedback

2Reliability

If the lock-up command pressure is delayed to prevent shock, then pressure following ability improves, but lock-up capacity is not generated and engine torque becomes excessively large

Engineering Contradiction:
Improvelock-up clutch engagement reliabilityVSAvoidengine torque
Core Design Contradiction:
ReliabilityVSPower

Solution Approach 1:

The invention applies preliminary anti-action by detecting the rising rate of line pressure in advance and proactively reducing engine torque before engine racing occurs. The ECU calculates the rising rate of line pressure and, when it exceeds a threshold, immediately reduces engine torque output to prevent the harmful effect of engine racing during lock-up clutch engagement.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The invention implements feedback control by continuously monitoring the line pressure rising rate and adjusting engine torque accordingly. The ECU calculates the rising rate of line pressure in real-time and uses this feedback information to dynamically control engine torque, reducing it when the rising rate is high and restoring it when the rising rate decreases, thereby preventing engine racing while maintaining pressure stability.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3187744B1Vehicle lockup clutch control device
Publication Date: 2018.08.08 NISSAN MOTOR CO LTD
  • EP3187744B1 patent drawingFigure 1
  • EP3187744B1 patent drawingFigure 2
  • EP3187744B1 patent drawingFigure 3

AI summary

The purpose of the present invention is to provide a vehicle lock-up clutch control device that suppresses engine racing when a lock-up clutch is engaged at the time a vehicle starts moving. A torque converter (4) having a lock-up clutch (3) is disposed between an engine (1) and a continuously variable transmission (6). A vehicle is provided with an initial-motion lock-up control means that, if a line pressure, which is the source pressure of the actual lock-up oil pressure, is rising when the lock-up clutch (3) is engaged at the time the vehicle starts moving, delays the rise in lock-up command pressure. The initial-motion lock-up control means executes a torque reduction in the engine (1) at least during the delay in lock-up command pressure.