Transmission Hydraulic Assembly With Split Pump Pressure Control
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Solution Overview
Problem
Existing hydraulic arrangements for vehicle transmissions face inefficiencies due to the need for separate hydraulic system and lubrication circuits, leading to power losses and suboptimal performance.
Innovation Solution
A hydraulic arrangement with a system path and lubrication path, utilizing either variable or constant displacement pumps, and selection valves to adapt hydraulic pressure and flow based on vehicle transmission parameters, optimizing power usage and reducing losses through flexible pump configurations and discrete volume flow adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single pump supplies both system circuit and lubrication circuit, then device complexity is reduced, but power losses increase due to inability to optimize flow for each circuit separately
Solution Approach 1:
The hydraulic system is segmented into two separate pumps: a first pump dedicated to the system circuit and a second pump dedicated to the lubrication circuit. This segmentation allows each pump to be independently controlled and optimized for its specific circuit requirements, thereby reducing hydraulic power losses while maintaining manageable device complexity through functional separation.
2Device complexity
If constant displacement pumps are used, then device complexity is reduced, but adaptability to different transmission states deteriorates
Solution Approach 1:
The system employs dynamic control through a control unit that continuously monitors transmission state parameters (rotational speed, torque, power) and adjusts the displacement of variable displacement pumps accordingly. This dynamic adaptation allows the hydraulic system to optimize power delivery and reduce losses across varying operating conditions while maintaining reasonable device complexity through electronic control.
Solution Approach 2:
The pumps are designed as variable displacement pumps whose displacement parameters can be continuously adjusted based on transmission state. The control unit modifies pump displacement parameters in response to changing transmission conditions (speed, torque, power), enabling the system to adapt to different operating states and optimize hydraulic power delivery without requiring overly complex mechanical control mechanisms.
3Adaptability or versatility
If variable displacement pumps are used, then adaptability to different transmission states is improved, but device complexity increases
Solution Approach 1:
The system replaces complex mechanical displacement control mechanisms with electronic control systems. The control unit uses electronic sensors and actuators to adjust pump displacement, substituting sophisticated mechanical linkages with more manageable electronic control architecture. This reduces device complexity while maintaining the adaptability benefits of variable displacement pumps.
Solution Approach 2:
A control unit acts as an intermediary between the transmission state sensors and the variable displacement pumps. This intermediary processes transmission state information and translates it into appropriate pump control signals, simplifying the overall system architecture by decoupling the sensing and actuation functions while maintaining adaptability to different operating conditions.
4Loss of energy
If separate pumps for system and lubrication circuits are used, then power losses are reduced through optimized flow control, but device complexity increases
Solution Approach 1:
The control unit serves multiple functions: it monitors transmission state parameters, controls both variable displacement pumps, and optimizes power delivery to both circuits simultaneously. This multi-functionality allows the system to achieve optimized flow control for reduced power losses while avoiding the full complexity burden of completely separate control systems for each pump, as the control unit manages both circuits in an integrated manner.
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 enhances the efficiency of vehicle transmission operations by dynamically adjusting hydraulic pressures and flows, reducing power losses and optimizing the hydraulic arrangement for specific vehicle requirements, thereby improving overall transmission performance.
Implementation Method 1
Constant-displacement pumps displace a constant hydraulic volume with each revolution, so that the flow rate remains constant at the same pump speed
Implementation Method 2
The pump combination can be adapted depending on the drive speed and thus on the required hydraulic pressures and power losses
Implementation Method 3
The pump combination or the variable displacement pump can be adapted depending on the drive speed and thus on the required hydraulic pressures and power losses
Data Source
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AI summary
The invention relates to a hydraulic arrangement (10) for a vehicle transmission, comprising: - a hydraulic system path (12) leading to a hydraulic system circuit (16) with a system pressure (p_sys), - a hydraulic lubrication path (14) leading to a hydraulic lubrication circuit (18) with a lubrication pressure (p_lub), and - a branch point (20) to which the two hydraulic paths (12, 14) are connected on the output side. A variable displacement pump (24) or a pump combination comprising at least two fixed displacement pumps is hydraulically connected to the input side of the branch point (20). A variable displacement pump (24) or at least one fixed displacement pump is hydraulically connected to the output side of the branch point (20) and is integrated into the hydraulic system path (12).