Automatic Transmission Line Pressure Control for Sudden Stop Clutch Protection

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Solution Overview

Problem

Automatic transmissions with oil pressure control face issues during sudden stops, where transmission oil flows to one side, leading to incomplete clutch engagement, excessive slippage, and potential damage upon acceleration.

Innovation Solution

A method involving a controller that determines a sudden stop and subsequent takeoff, increasing line pressure, limiting takeoff if excessive slippage is detected, and reducing torque input to prevent clutch damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the vehicle accelerates immediately after a sudden stop, then the takeoff response is improved, but the transmission clutches suffer from incomplete engagement and excessive slippage leading to durability degradation

Engineering Contradiction:

Improvetakeoff response speedVSAvoidclutch durability

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The controller predicts the driver's takeoff intent based on accelerator pedal depression rate and other parameters before actual acceleration occurs. This preliminary detection allows the system to prepare by increasing line pressure and adjusting turbine torque in advance, ensuring proper clutch engagement from the start of acceleration and preventing slippage-related durability issues

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts critical parameters including line pressure, turbine torque, and clutch engagement timing based on the predicted takeoff condition. By changing these parameters proactively rather than reactively, the system ensures optimal clutch engagement characteristics during rapid acceleration, balancing takeoff response with clutch protection

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the line pressure is increased to ensure proper clutch engagement, then the clutch durability is improved, but the response time for pressure normalization increases causing excessive slippage

Engineering Contradiction:

Improveclutch durabilityVSAvoidpressure normalization time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The controller increases line pressure in advance based on predicted takeoff conditions rather than waiting for acceleration to begin. This preliminary pressure buildup ensures that when the clutch engages, proper oil pressure is already available, eliminating the delay in pressure normalization and preventing excessive slippage during the critical engagement phase

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system replaces passive mechanical clutch engagement with an actively controlled hydraulic pressure system. By using electronic control to anticipate and prepare the hydraulic pressure, the system eliminates the mechanical delay inherent in traditional clutch engagement, achieving both rapid response and proper engagement pressure simultaneously

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If the turbine velocity dissipates during takeoff, then the clutch slippage increases causing durability decrease, but maintaining high turbine velocity requires excessive torque input

Engineering Contradiction:

Improveclutch durabilityVSAvoidtorque input

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The controller continuously monitors turbine velocity, line pressure, and clutch engagement status, using this feedback to dynamically adjust torque input and pressure control. This closed-loop control prevents turbine velocity dissipation by making real-time adjustments that maintain optimal engagement conditions without requiring excessive torque input, thereby protecting clutch durability while managing energy consumption

Inventive Principle:

Principle #23Feedback

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

Prevents dissipation of turbine velocity, maintains clutch durability, and avoids fire damage by ensuring proper oil pressure and controlled torque application.

Implementation Method 1

an automatic transmission controlled by oil pressure

Methodology Applied

Scientific EffectOil pressure control: Hydraulic Press

Implementation Method 2

the transmission oil may flow to one side, temporarily emptying the oil pan

Methodology Applied

Scientific EffectFluid flow: Convection

Data Source

PatentUS10533661B2Method for controlling vehicle equipped with automatic transmission

Publication Date: 2020.01.14 HYUNDAI MOTOR CO LTD

AI summary

A method for controlling a vehicle installed with an automatic transmission, includes: a sudden stop determination step in which a controller determines whether the vehicle has stopped at a speed greater than or equal to a reference deceleration speed and whether a post-stop elapsed time is within a first reference time; a takeoff determination step in which the controller determines whether an input torque of the transmission exceeds zero within the first reference time when a shift range is in a driving range; a pressure control step in which, when the vehicle takes off, the controller elevates a line pressure of the transmission; a limitation determination step in which if a slippage extent of a turbine exceeds a reference slippage value for a second reference time, the controller limits the takeoff; and a torque reduction step in which the controller reduces a takeoff torque input of the transmission.