Closed-Loop Clutch Pressure Control Module for Automatic Transmissions
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Solution Overview
Problem
Existing hydraulic clutch pressure control systems face challenges in mounting pressure sensors within the clutch chamber due to physical constraints, and there is a need for a pre-packaged, readily-installable module that can fit into available transmission housing space without significant modification of other components.
Innovation Solution
A closed-loop hydraulic clutch pressure control system is implemented using a pressure control module with solenoid valves, a pilot valve, a pilot pressure sensor, a pressure regulating valve, and a control arrangement that generates pilot valve drive signals based on clutch pressure commands and sensed pilot pressure, allowing for direct measurement of clutch pressure without the need for a sensor in the clutch chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pressure sensor is mounted in the clutch chamber to enable direct clutch pressure control, then measurement precision is improved, but device complexity and installation difficulty increase due to physical constraints in the clutch chamber
Solution Approach 1:
The patent introduces a pilot pressure sensor as an intermediary element that measures pilot pressure instead of directly measuring clutch pressure in the constrained clutch chamber. The pilot pressure serves as a proxy that correlates with clutch pressure, enabling indirect measurement that avoids the physical constraints of the clutch chamber while still providing the necessary control information.
Solution Approach 2:
The control system is segmented into separate functional modules: a pilot pressure control module that measures and controls pilot pressure, and a clutch pressure control function that uses the pilot pressure information to regulate clutch pressure. This segmentation allows the sensor to be mounted in the accessible pilot pressure line rather than in the constrained clutch chamber, reducing installation complexity.
2Ease of manufacture
If a pre-packaged pressure control module is used to simplify installation, then ease of manufacture and installation are improved, but device complexity increases due to integration of multiple components
Solution Approach 1:
The patent combines multiple control functions (pilot pressure sensing, pilot pressure control, and clutch pressure regulation) into a single integrated pressure control module. This merging of functions into one pre-packaged unit simplifies installation and manufacturing while the internal integration manages the complexity, making the system easier to implement overall.
Solution Approach 2:
The pressure control module is designed as a universal component that can be integrated into existing transmission systems without requiring significant modification of other transmission components. The module performs multiple functions (sensing, control, and regulation) within a single unit that fits into available transmission housing space, providing multi-functionality that simplifies the overall system implementation.
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 solution provides effective clutch pressure control with a pre-packaged module that fits within the transmission housing, achieving smooth and coordinated gear engagement without requiring significant modification of other transmission components, thereby enhancing shift performance.
Implementation Method 1
a plurality of solenoid valves, each of the solenoid valves configured to receive an input of the pressurized hydraulic fluid and to provide a variable output pressure of the pressurized hydraulic fluid in response to an electric control signal
Implementation Method 2
means for sensing output pressure from each of the solenoid valves of the plurality of solenoid valves
Implementation Method 3
Hydraulic fluid controls can be found in a variety of automotive applications such as automatic speed change transmissions
Data Source
AI summary
An automatic transmission is disclosed that includes a clutch pressure control module housing having therein:(1) a plurality of solenoid valves, each of the solenoid valves configured to receive an input of the pressurized hydraulic fluid and to provide a variable output pressure of pressurized hydraulic fluid in response to an electric control signal;(2) means for sensing output pressure from each of the solenoid valves of the plurality of solenoid valves; and(3) electronic control means configured to generate electric control signals to one or more of the solenoid valves of the plurality of solenoid valves in response to (i) a clutch pressure command signal or a solenoid pressure command signal, and (ii) a solenoid output pressure signal from the means for sensing output pressure.The solenoid valves provide hydraulic control signals to clutch hydraulic pressure control valves, which in turn provide hydraulic power to clutch actuators.