Transmission Hydraulic Circuit Layout for Independent Pressure Control
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Solution Overview
Problem
Existing hydraulic systems for motor vehicle transmissions face challenges in controllability and efficiency, particularly in managing pressure circuits and energy distribution, leading to complex coordination and increased energy demand.
Innovation Solution
A hydraulic system with an electromagnetically actuated first pressure control valve, a spring-loaded shut-off valve, and a proportional valve, which allows for independent control of pressure circuits and efficient energy allocation between pump output lines, enabling open-loop and closed-loop system operation while reducing energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single pump supplies both high-pressure and low-pressure circuits, then device complexity is reduced, but pressure control precision deteriorates
Solution Approach 1:
The single pump is segmented into two independent pressure regions (high-pressure region with first pump output line and low-pressure region with second pump output line) that operate independently. Each pressure region can be controlled separately through dedicated control valves, achieving precise pressure control while maintaining a compact single-pump structure.
2Measurement precision
If complex closed-loop control systems are used for pressure management, then pressure control precision is improved, but device complexity increases
Solution Approach 1:
The system employs self-regulating mechanisms where pressure control valves automatically adjust based on pressure differential signals from the respective pressure circuits. The first pressure control valve regulates high-pressure circuit independently, while the second pressure control valve manages low-pressure circuit, eliminating the need for complex centralized closed-loop control systems.
3Measurement precision
If separate pumps are used for high-pressure and low-pressure circuits, then pressure control precision is improved, but device complexity increases
Solution Approach 1:
The patent implements a nested structure where two independent pressure regions are integrated within a single pump housing. The high-pressure and low-pressure circuits are nested within the same pump body, sharing common components like the drive shaft and housing, while maintaining independent pressure control through separate output lines and control valves.
4Measurement precision
If electromagnetically actuated pressure control valves are used, then pressure control precision is improved, but energy demand increases
Solution Approach 1:
The electromagnetically actuated pressure control valves operate in a partial action mode, using electromagnetic force only when pressure adjustment is needed. During normal operation, the valves maintain their position through spring forces and pressure balance, consuming minimal energy. The electromagnetic actuation provides precise control only when required, rather than continuous energy consumption.
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 ensures reliable supply to hydraulic consumers, reduces energy demand, and simplifies pressure management, enhancing controllability and cost-effectiveness by allocating functions to different valves and using separate pressure regions.
Implementation Method 1
The first pressure control valve is electromagnetically actuated and includes an inlet, which is connected to the first pressure circuit. The first pressure control valve is configured for making a pressure available, at an outlet, which has been reduced from the inlet or is the same. The pressure reduction takes place depending on a current supply to a solenoid of the first pressure control valve.
Implementation Method 2
The hydraulic system includes a spring-loaded shut-off valve. The outlet of the first pressure control valve is connected to a first control surface of the shut-off valve. The shut-off valve is configured for connecting, in the non-actuated condition, the second pump output line to the second pressure circuit.
Data Source
AI summary
A hydraulic system (HY) for a motor vehicle transmission (G) includes at least one pump (P), two pump output lines (P1, P2) for supplying a first pressure circuit (1) and a second pressure circuit (2), and an electromagnetically actuated, first pressure control valve (EDS1), the inlet (EDS11) of which is connected to the first pressure circuit (1) and the outlet (EDS12) of which is connected to a first control surface (PVC) of a spring-loaded shut-off valve (PV). The shut-off valve (PV) is configured for connecting, in a non-actuated condition, the second pump output line (P2) to the second pressure circuit (2) and, in the condition actuated via the first control surface (PVC), disconnecting the second pump output line (P2) from the second pressure circuit (2). A motor vehicle transmission (G) including such a hydraulic system (HY) and a drive train including such a motor vehicle transmission (G) are also provided.