Hydraulic Control System for CVT with Segmented Subsystems
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Solution Overview
Problem
Conventional hydraulic control systems for continuously variable transmissions (CVTs) face challenges in efficiency, responsiveness, and smoothness, necessitating an improved configuration that enhances performance while being cost-effective.
Innovation Solution
A hydraulic control system comprising a pressure regulator subsystem, ratio control subsystem, torque converter control subsystem, clutch control subsystem, and electronic transmission range selection (ETRS) subsystem, with advanced valve and solenoid configurations, including an accumulator for automatic engine start/stop functionality, to manage pressurized hydraulic fluid effectively and optimize CVT operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional hydraulic control system is used with a main pump providing pressurized fluid to valves and solenoids, then the system can perform basic CVT functions, but the efficiency, responsiveness, and smoothness are insufficient
Solution Approach 1:
The hydraulic control system is divided into multiple independent subsystems: pressure regulator subsystem, ratio control subsystem, torque converter control subsystem, clutch control subsystem, and ETRS subsystem. Each subsystem has dedicated valves and actuators, allowing independent optimization of hydraulic flow paths and pressure regulation, thereby improving overall system efficiency and reducing energy losses through targeted pressure control.
Solution Approach 2:
The system implements variable pressure regulation across different subsystems based on operational requirements. The pressure regulator subsystem dynamically adjusts pressure parameters for each control function, enabling optimal hydraulic pressure delivery that improves responsiveness and smoothness while minimizing energy consumption through adaptive pressure management rather than constant high-pressure delivery.
2Speed
If the hydraulic control system uses multiple valves and solenoids for precise control, then responsiveness and smoothness improve, but the device complexity increases
Solution Approach 1:
By segmenting the control functions into separate subsystems with dedicated valves and solenoids, the system achieves precise and rapid control for each function without requiring complex cross-functional valve arrangements. This modular approach improves responsiveness while making the overall system architecture more manageable despite the increased number of components.
Solution Approach 2:
The hydraulic control system employs a common pressurized fluid supply from the main pump that serves all subsystems simultaneously. This universal fluid delivery approach allows multiple control functions to operate in parallel with shared infrastructure, reducing the need for separate pumping systems and simplifying the overall architecture while maintaining fast response times across all control functions.
3Adaptability or versatility
If the system implements advanced features like torque converter control and automatic engine start/stop, then functionality and performance improve, but the manufacturing cost and system complexity increase
Solution Approach 1:
The control system is organized into distinct functional subsystems (torque converter control, clutch control, ETRS, etc.), each with dedicated valves and actuators. This segmentation allows manufacturers to produce standardized modular components that can be assembled into different configurations, reducing tooling costs and simplifying quality control while providing advanced functionality.
Solution Approach 2:
The hydraulic control system uses a universal pressurized fluid distribution network that serves multiple advanced functions including torque converter control, clutch engagement, and ETRS operations. This shared hydraulic infrastructure reduces the need for separate fluid delivery systems for each function, lowering manufacturing costs while maintaining versatile control capabilities across all subsystems.
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 CVT operations by precisely controlling hydraulic fluid pressure and flow, ensuring improved torque converter control and automatic engine start/stop functionality, thereby addressing the limitations of conventional systems.
Implementation Method 1
a pressure regulator subsystem providing a pressurized hydraulic fluid
Implementation Method 2
A first solenoid is in direct upstream communication with the first mode valve assembly, wherein a pressure signal from the first solenoid moves the first mode valve
Data Source
AI summary
A hydraulic control system for a CVT includes a pressure regulator subsystem, a ratio control subsystem, a torque converter control (TCC) subsystem, a clutch control subsystem, an electronic transmission range selection subsystem, and is enabled for automatic engine start/stop (ESS) functionality.