Vehicle Lockup Clutch Hydraulic Control for Shock Suppression

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Solution Overview

Problem

Existing power transmission systems for vehicles face challenges in accurately controlling lockup end control, particularly when the lockup region is expanded, leading to unexpected shock and prolonged control time due to inadequate hydraulic pressure management during the release of the lockup clutch.

Innovation Solution

A power transmission system that includes an electronic control unit to adjust the initial hydraulic pressure of lockup end control based on the difference between output and driven torque, ensuring higher initial pressure for larger torque differences to suppress shock and reduce control time, and adjusts the hydraulic pressure output period accordingly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the lockup region is expanded to a slip type and lockup end control is executed from various slip situations, then the adaptability of the system is improved, but unexpected shock occurs and the lockup end control time is unnecessarily extended

Engineering Contradiction:

Improvelockup end control adaptabilityVSAvoidshock during lockup end control

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting the control hydraulic pressure based on the slip situation. Specifically, the control unit calculates the slip ratio between the input member and output member, and accordingly modifies the control hydraulic pressure to the lockup clutch during lockup end control. This ensures appropriate pressure application across various slip conditions, preventing shock while maintaining control accuracy.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent implements dynamics by transitioning from fixed command pressure to dynamic pressure adjustment. The control hydraulic pressure is continuously modified based on real-time slip ratio calculations, allowing the system to adapt to changing operating conditions during lockup end control, thereby preventing shock across diverse slip situations.

Inventive Principle:

Principle #15Dynamics

2Device complexity

If the command pressure after learning is used evenly for lockup end control, then the device complexity is reduced, but the control accuracy deteriorates under expanded lockup region conditions

Engineering Contradiction:

Improvecontrol system complexityVSAvoidlockup end control accuracy

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The patent applies feedback by calculating the slip ratio between the input member and output member during lockup end control and using this information to adjust the control hydraulic pressure. The control unit continuously monitors the slip situation and modifies the pressure accordingly, creating a closed-loop control system that maintains high accuracy without excessive complexity.

Inventive Principle:

Principle #23Feedback

3Productivity

If the hydraulic pressure output period is shortened to reduce lockup end control time, then the productivity is improved, but the shock suppression capability is reduced

Engineering Contradiction:

Improvelockup end control speedVSAvoidshock during release

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting both the control hydraulic pressure magnitude and the pressure application timing based on the slip ratio. The control unit calculates the optimal pressure profile considering the current slip situation, thereby shortening the control time when appropriate while maintaining shock suppression capability when needed.

Inventive Principle:

Principle #35Parameter changes

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

The system effectively suppresses shock during lockup end control and reduces the overall time required for the process by dynamically managing hydraulic pressure based on torque differences and vehicle conditions.

Implementation Method 1

The lockup clutch is configured to directly connect an input member and an output member of the torque converter with supply of control hydraulic pressure to a control oil chamber

Methodology Applied

Scientific EffectHydraulic pressure: Pressure Increase

Implementation Method 2

execute lockup end control that decreases the control hydraulic pressure to release the lockup clutch

Methodology Applied

Scientific EffectHydraulic pressure reduction: Pressure Drop

Data Source

PatentUS10088038B2Power transmission system for vehicle

Publication Date: 2018.10.02 TOYOTA JIDOSHA KK

AI summary

If the difference between output torque output from an engine and load torque from drive wheels is large and torque input to a lockup clutch is large, since a value of lockup command pressure at which lockup engagement pressure in lockup end control becomes constant standby pressure is set to be high, fast release of the lockup clutch or racing of the engine is suppressed during the lockup end control. If torque input to the lockup clutch is small, the value of the lockup command pressure at which the lockup engagement pressure in the lockup end control becomes the constant standby pressure is set to be low, and a hydraulic pressure output period during which hydraulic pressure is output to the lockup clutch is set to be short.