Hydraulic Control System Default Gear Engagement via Exhaust Circuit

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Solution Overview

Problem

Conventional hydraulic control systems for automatic transmissions fail to provide effective default gear ratios during electronic control loss, limiting vehicle mobility in default conditions such as solenoid or controller failures.

Innovation Solution

A hydraulic control system incorporating a default enable valve, a default select valve, and clutch regulation valves that selectively engage clutches using pressurized hydraulic fluid to provide one or more default gear ratios, allowing manual operation to select between park, neutral, drive, and reverse positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional hydraulic control system is used, then the transmission can operate under normal electronic control, but it fails to provide default gear ratios during electronic control loss

Engineering Contradiction:

Improvetransmission operation during default conditionVSAvoidgear ratio availability during default condition

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The hydraulic control system is pre-configured with default gear pathways that are activated automatically when electronic control is lost. The valve body includes dedicated default gear circuits that can engage clutches and brakes without electronic solenoid control, ensuring the transmission can maintain operational gear ratios during default conditions

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

A default control subsystem is introduced as an intermediary between the electronic control system and the hydraulic actuators. This subsystem includes default enable valves and default select valves that can receive hydraulic signals independently of electronic control, allowing the transmission to engage default gear ratios when the electronic system fails

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If the transmission shifts to neutral during default condition, then safety is improved, but vehicle mobility is limited

Engineering Contradiction:

Improvesafety during default conditionVSAvoidvehicle mobility during default condition

Core Design Contradiction:

Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The transmission system dynamically adapts its gear state based on control availability. During normal operation, electronic control provides full gear selection capability. During default conditions, the system automatically transitions to a limited gear set configured through the default control subsystem, maintaining mobility while ensuring safe operation without requiring driver intervention

Inventive Principle:

Principle #15Dynamics

3Reliability

If normally high solenoids are used to engage clutches during default, then default gear capability is improved, but device complexity and cost increase

Engineering Contradiction:

Improvedefault gear engagement capabilityVSAvoidsolenoid configuration complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The existing solenoids in the transmission are designed to perform multiple functions: normal electronic control operation and default gear engagement. By configuring the valve body to route hydraulic pressure through existing solenoid pathways during default conditions, the system achieves default gear capability without adding specialized normally high solenoids or other complex components

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

Enables the transmission to maintain functionality and provide default gear ratios during electronic control loss, ensuring vehicle mobility in default conditions by selectively engaging clutches through the hydraulic control system.

Implementation Method 1

a clutch regulation valve having an exhaust port in fluid communication with the default control subsystem, an input port in communication with the pressure regulation subsystem, and a clutch feed port in fluid communication with the clutch, wherein the clutch regulation valve selectively allows fluid communication between the input port and the clutch feed port and the exhaust port and the clutch feed port

Methodology Applied

Scientific EffectHydraulic fluid pressure: Pressure Increase

Data Source

PatentUS10161508B2Hydraulic control system for an automatic transmission having default gears applied through a clutch hydraulic exhaust circuit

Publication Date: 2018.12.25 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

A hydraulic control system for a transmission is provided. The hydraulic control system provides one or more default gears during a default condition when the transmission loses electronic control. The hydraulic control system includes a default enable valve, a default select valve, and a plurality of clutch regulation valves. The default enable valve and the default select valve feed hydraulic fluid through exhaust circuits to a set number of the clutch regulation valves during a default condition in order to provide a default gear ratio.