Hydraulic Control System for Automatic Transmission
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Solution Overview
Problem
Conventional hydraulic control systems in automatic transmissions face challenges in achieving improved efficiency, responsiveness, and smoothness, necessitating a more effective and cost-effective configuration.
Innovation Solution
A hydraulic control system that includes a pressure regulator subsystem, an electronic transmission range selection (ETRS) subsystem, and a clutch actuation control subsystem, utilizing a source of pressurized hydraulic fluid to engage multiple clutch actuators through a network of valves and solenoids, allowing for precise control of torque transmitting devices for various gear ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional hydraulic control system with a main pump driven by the engine is used, then the system can provide pressurized hydraulic fluid to valves and solenoids for actuating torque transmitting devices, but the system exhibits insufficient efficiency, responsiveness, and smoothness
Solution Approach 1:
The hydraulic control system is divided into multiple independent pump assemblies, each associated with a specific clutch actuator. This segmentation allows each pump to be optimized for its specific function and operated independently, improving overall system efficiency and responsiveness while maintaining manageable complexity through modular architecture.
Solution Approach 2:
The system employs variable displacement vane pumps that can dynamically adjust their output based on real-time hydraulic fluid demand. This dynamic adjustment capability allows the pumps to match supply with actual clutch actuation needs, significantly improving efficiency by avoiding constant full-pressure operation and enhancing responsiveness to control signals.
2Device complexity
If a main pump provides pressurized hydraulic fluid to all valves and solenoids, then the system structure is simplified, but the responsiveness and smoothness of clutch actuation deteriorates
Solution Approach 1:
The centralized hydraulic supply is segmented into multiple independent pump-clutch assemblies. Each assembly has its own pump that can respond independently to control signals, eliminating the delays associated with a single centralized pump serving multiple clutches. This segmentation directly improves responsiveness while the modular design keeps the overall structural complexity manageable.
Solution Approach 2:
Each pump assembly is pre-configured and positioned near its associated clutch actuator, allowing hydraulic fluid to be delivered directly to the required location without traveling through extensive piping from a centralized pump. This preliminary positioning of hydraulic power sources near their points of use reduces transmission delays and improves actuation speed.
3Productivity
If a conventional hydraulic control system is used, then cost-effectiveness is maintained, but performance in terms of efficiency and smoothness is insufficient
Solution Approach 1:
The system uses modular pump assemblies that can be manufactured as standardized units and assembled into the transmission. This modularity enables economies of scale in manufacturing individual components while allowing flexible configuration to match specific transmission designs, maintaining cost-effectiveness despite the advanced functionality.
Solution Approach 2:
The system replaces traditional engine-driven mechanical pump operation with electrically controlled variable displacement pumps. This substitution allows for more precise electronic control of hydraulic delivery, improving efficiency and smoothness while the use of standardized electric motor components keeps manufacturing costs reasonable.
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
The system enhances the efficiency, responsiveness, and smoothness of automatic transmissions by providing precise control over clutch engagement and disengagement, improving overall performance while maintaining cost-effectiveness.
Implementation Method 1
A hydraulic control system includes a source of pressurized hydraulic fluid that communicates with an analog electronic transmission range selection (ETRS) subsystem
Data Source
AI summary
A hydraulic control system for a transmission includes a source of pressurized hydraulic fluid that communicates with an electronic transmission range selection (ETRS) subsystem or manual valve and a clutch actuation subsystem.