Hydraulic Control System for Automatic Transmission Default Modes
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Solution Overview
Problem
Conventional hydraulic control systems for automatic transmissions lack the ability to provide forward and reverse driving states during default conditions, where electronic control is absent due to failures or malfunctions, leading to a need for a cost-effective and improved hydraulic control system that can operate hydraulically.
Innovation Solution
A hydraulic control system with a pressure regulation subsystem, a manual valve assembly, and default disable and select valve assemblies, which allow for the engagement of torque-transmitting mechanisms to provide multiple default modes of operation, including forward and reverse gear ratios, through a combination of valve configurations and solenoid control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional hydraulic control system is used, then the transmission can operate under normal electronic control conditions, but it cannot provide forward and reverse driving states during default conditions when electronic control is absent
Solution Approach 1:
The hydraulic control system is segmented into multiple independent valve assemblies (manual valve assembly, default disable valve assembly, default select valve assembly) that can operate autonomously. Each valve assembly handles specific functions, allowing the system to provide forward and reverse gear states through hydraulic control alone when electronic control is unavailable, thus improving reliability during default conditions while maintaining adaptability through modular functionality.
2Reliability
If additional valve assemblies are added to enable default mode operation, then the transmission can maintain operational capability during electronic failures, but the device complexity increases
Solution Approach 1:
The manual valve assembly is designed with multi-functionality, serving both normal electronic-controlled operation and default hydraulic-only operation. The default disable valve assembly and default select valve assembly are integrated into the existing hydraulic circuitry, allowing them to provide forward and reverse gear states without requiring completely separate systems. This universal design approach enables the transmission to maintain operational capability during electronic failures while minimizing the increase in device complexity through shared components and circuits.
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 operational capability during default conditions by engaging torque-transmitting mechanisms to achieve desired gear states, ensuring continued vehicle functionality even without electronic control.
Implementation Method 1
a pressure regulation subsystem in fluid communication with a pump, the pressure regulation subsystem being configured to provide pressurized hydraulic fluid
Implementation Method 2
A one-way valve is configured to permit a portion of the pressurized hydraulic fluid to flow to the second-priority hydraulic circuit when the hydraulic control system is in a default mode of operation
Data Source
AI summary
A hydraulic control system for a motor vehicle transmission includes a pressure regulation subsystem and a manual valve assembly in fluid communication with the pressure regulation subsystem. The manual valve assembly is moveable between at least park, neutral, drive, and reverse positions. A default disable valve assembly is in fluid communication with the manual valve assembly, a default disable solenoid valve assembly, and a default select valve assembly. A one-way valve may be provided to permit hydraulic fluid to flow to a second-priority hydraulic circuit when in a default mode of operation. A combined main regulation and priority valve may be provided to pressurize line pressure as a first priority, pressurize the second-priority hydraulic circuit as a second priority, and to feed excess pressure to a decrease-pressure circuit as a third priority.