CVT Hydraulic Control System with Boost Valve Segmentation
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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, cost-effective configuration.
Innovation Solution
A hydraulic control system with a pressure regulator subsystem, cooler subsystem, manual valve assembly, torque converter control valve assembly, boost valve assembly, clutch control solenoid, and TCC control solenoid, which include clutch and TCC pressure regulator valve assemblies, enabling selective communication of pressurized hydraulic fluid for clutch and torque converter control, with fail-safe mechanisms to ensure system reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional hydraulic control system is used for CVT, then the system can provide basic cooling and lubrication functions, but the efficiency, responsiveness, and smoothness of CVT operations are insufficient
Solution Approach 1:
The hydraulic control system is divided into separate functional subsystems: a pressure regulator subsystem with dedicated regulator valve assembly, a cooler subsystem with temperature control, a manual valve assembly for clutch control, and a torque converter control valve assembly. Each subsystem independently manages specific functions, improving overall system efficiency and responsiveness without creating excessive complexity through modular design.
Solution Approach 2:
The pressure regulator valve assembly preliminarily regulates hydraulic fluid pressure before distribution to various actuators. The cooler subsystem preliminarily cools the hydraulic fluid before it reaches torque transmitting devices, ensuring optimal operating conditions are established in advance for improved CVT operational efficiency and smoothness.
2Reliability
If the boost valve is positioned upstream of the pressure regulator, then fail-safe functionality is improved, but the system complexity increases
Solution Approach 1:
The boost valve assembly is positioned upstream of the pressure regulator valve assembly to provide beforehand cushioning against potential solenoid failures. This configuration ensures that if a solenoid fails, the boost valve can still regulate pressure to maintain basic clutch and torque converter functionality, improving reliability without significantly increasing system complexity through strategic component placement.
Solution Approach 2:
The pressure regulator valve assembly acts as an intermediary between the boost valve assembly and downstream actuators. This intermediate regulation stage allows the boost valve to provide fail-safe pressure control while the regulator valve fine-tunes pressure for optimal clutch and torque converter operation, distributing complexity across multiple manageable components.
3Measurement precision
If pressure regulation is implemented at multiple stages, then hydraulic fluid pressure control precision is improved, but the device complexity increases
Solution Approach 1:
Pressure regulation is segmented into two distinct stages: the boost valve assembly provides first-stage pressure control by regulating pressure from the hydraulic pump, and the pressure regulator valve assembly provides second-stage precision pressure control before fluid reaches actuators. This segmentation improves pressure control precision while managing complexity through clear functional separation of regulation tasks.
Solution Approach 2:
The boost valve assembly performs preliminary pressure regulation to establish a controlled pressure range before the fluid reaches the pressure regulator valve assembly. This preliminary action reduces the adjustment range required by the second-stage regulator, improving overall pressure control precision while distributing the complexity of precision control across two specialized components.
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 regulating hydraulic fluid pressure and ensuring reliable clutch and torque converter control, including fail-safe functionality in case of solenoid failures.
Implementation Method 1
a cooler subsystem for reducing a temperature of the pressurized hydraulic fluid
Implementation Method 2
A clutch control solenoid is configured to move the boost valve to the boost position and the control valve to the release position
Data Source
AI summary
A hydraulic control system with clutch and torque converter control for a CVT includes a pressure regulator subsystem, a cooler subsystem, a manual valve assembly, and a torque converter control valve assembly connected to the torque converter clutch (TCC) and the cooler subsystem. A boost valve assembly is connected to the pressure regulator subsystem, the manual valve assembly, and the torque converter clutch control valve assembly. A clutch control solenoid is configured to move the boost valve to the boost position and the control valve to the release position and to control a pressure of the hydraulic fluid provided to the manual valve assembly. A TCC control solenoid is configured to move the boost valve to the boost position and to control a pressure of the hydraulic fluid provided to the torque converter control valve assembly.