Transmission Clutch Control for Upshift Delay and Engine Overspeed

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Solution Overview

Problem

Current transmission control systems experience upshift delays and engine overspeed conditions, leading to potential damage and adverse effects on vehicle performance, particularly in high-performance vehicles.

Innovation Solution

A system and method that utilize two torque transmitting mechanisms with a controller to monitor transmission operating conditions, pressurizing an apply chamber to achieve gear ratios efficiently, reducing upshift delay by partially engaging the on-coming clutch before full engagement, and using a timer to ensure timely transition to the next gear ratio.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If engine overspeed protection control reduces engine torque request when engine speed or transmission input shaft speed is exceeded, then engine overspeed is prevented, but vehicle performance deteriorates due to torque drop

Engineering Contradiction:

Improveengine overspeed protectionVSAvoidvehicle power output

Core Design Contradiction:

ReliabilityVSPower

Solution Approach 1:

The system performs preliminary action by pre-engaging the on-coming clutch before the off-going clutch fully disengages during upshift. This preliminary engagement preparation ensures that the on-coming clutch is ready to transmit torque immediately when needed, preventing engine overspeed without requiring torque reduction, thus maintaining vehicle power output while protecting against overspeed conditions

Inventive Principle:

Principle #10Preliminary action

2Reliability

If transmission upshift delay occurs during manual shift mode, then gear ratio change is delayed, but engine overspeed condition arises causing potential damage

Engineering Contradiction:

Improveengine protection from overspeedVSAvoidupshift delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The system performs preliminary action by pre-engaging the on-coming clutch before the off-going clutch fully disengages during upshift. This preliminary engagement preparation reduces the upshift delay time, ensuring that the gear ratio change occurs more quickly and preventing engine overspeed conditions that could cause damage

Inventive Principle:

Principle #10Preliminary action

3Productivity

If on-coming clutch is pre-engaged before upshift, then upshift delay is reduced, but clutch wear and heat generation increase

Engineering Contradiction:

Improveupshift speedVSAvoidclutch wear and heat

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary action by pre-engaging the on-coming clutch before the off-going clutch fully disengages, which reduces upshift delay and improves shift speed. The controller carefully manages the timing and pressure application to minimize unnecessary clutch slip and heat generation while achieving faster upshift response

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The controller continuously monitors transmission operating conditions including clutch engagement status, torque demands, and vehicle speed. This feedback mechanism allows the controller to adjust the pre-engagement timing and pressure levels in real-time, optimizing the balance between upshift speed and clutch wear/heat management based on actual operating conditions

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

This approach reduces upshift delay and prevents engine overspeed, enhancing vehicle performance by ensuring smoother gear transitions and minimizing component damage.

Implementation Method 1

The second torque transmitting mechanism has an apply chamber, where the apply chamber is pressurized at a first pressure level to achieve a first engaged position and is pressurized at a second pressure level to achieve a second engaged position

Methodology Applied

Scientific EffectHydraulic pressure: Hydraulic Press

Data Source

PatentUS8216111B2Clutch control for a transmission

Publication Date: 2012.07.10 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

A system and method for controlling torque includes a first torque transmitting mechanism and a second torque transmitting mechanism. The first torque transmitting mechanism is engageable to achieve a first gear ratio of the transmission. The second torque transmitting mechanism has an apply chamber that is pressurized at a first pressure level to achieve a first engaged position and is pressurized at a second pressure level to achieve a second engaged position. The first pressure level is less than the second pressure level and the second engaged position achieves a second gear ratio of the transmission. A controller is in communication with the first and second torque transmitting mechanisms. The controller includes a control logic for pressurizing the apply chamber of the second torque transmitting mechanism to the first pressure level if the first operating condition has exceeded a threshold operating condition.