Hydraulic Decoupling Unit Actuation for Inactive Drive Loss Reduction
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Solution Overview
Problem
Conventional drive trains with e-axles often incur unwanted losses due to inactive drives that are not decoupled, requiring active actuators which increase manufacturing and operating costs.
Innovation Solution
A method for passively actuating a decoupling unit in a drive train using existing hydraulic transmission elements, such as clutches or brakes, without additional active elements, by leveraging the actuation force and restoring force within the hydraulic system to control a normally open cut-out clutch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If active actuators with electric motors or electrically controlled valves are used to decouple inactive drives, then the decoupling function is reliable, but manufacturing costs and operating costs increase
Solution Approach 1:
The hydraulic system serves itself by using the actuation forces already present in the transmission elements (clutches or brakes) to actuate the decoupling unit. The system utilizes its own internal hydraulic resources - the actuation pressure lines and restoring pressure lines that already exist for the transmission elements - to passively actuate the decoupling unit without requiring external active actuators. This self-service approach eliminates the need for additional electric motors or electrically controlled valves while maintaining reliable decoupling functionality.
Solution Approach 2:
The existing hydraulic pressure lines in the transmission system serve multiple functions: they actuate the transmission elements (clutches or brakes) and simultaneously serve to actuate the decoupling unit. The actuation pressure line provides hydraulic pressure both for engaging the transmission elements and for closing the decoupling unit, while the restoring pressure line serves both to disengage transmission elements and to open the decoupling unit. This multi-functionality eliminates the need for dedicated actuators for the decoupling unit.
2Adaptability or versatility
If additional actuators are added to decouple inactive drives, then the decoupling capability is improved, but manufacturing costs increase
Solution Approach 1:
The existing hydraulic pressure lines in the transmission system serve multiple functions: they actuate the transmission elements (clutches or brakes) and simultaneously serve to actuate the decoupling unit. The actuation pressure line provides hydraulic pressure both for engaging the transmission elements and for closing the decoupling unit, while the restoring pressure line serves both to disengage transmission elements and to open the decoupling unit. This multi-functionality eliminates the need for dedicated actuators for the decoupling unit.
Solution Approach 2:
The actuation system for the transmission elements and the decoupling unit is merged into a single integrated hydraulic system. The pressure lines, control logic, and hydraulic resources are combined so that the same hydraulic infrastructure that controls the transmission elements also controls the decoupling unit. This merging reduces the total number of components and simplifies the manufacturing process.
3Speed
If active actuators are used for decoupling, then the decoupling response is fast, but energy consumption increases
Solution Approach 1:
The hydraulic system serves itself by using the actuation forces already present in the transmission elements (clutches or brakes) to actuate the decoupling unit. The system utilizes its own internal hydraulic resources - the actuation pressure lines and restoring pressure lines that already exist for the transmission elements - to passively actuate the decoupling unit without requiring external active actuators. This self-service approach eliminates the need for additional electric motors or electrically controlled valves while maintaining reliable decoupling functionality.
Solution Approach 2:
The hydraulic pressure that would otherwise be wasted or unused during transmission element operation is converted into a useful resource for actuating the decoupling unit. The actuation pressure and restoring pressure that are already generated for the transmission elements are repurposed to control the decoupling unit, turning what could be considered excess or wasted hydraulic energy into a beneficial actuation force for the decoupling function.
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 approach reduces manufacturing and operating costs by eliminating the need for additional actuators, minimizes energy consumption, and effectively reduces losses by decoupling inactive drives without impairing the function of existing transmission elements.
Implementation Method 1
the decoupling unit is passively actuated using an actuation force, which is provided in a hydraulic system, in an actuating direction via a first hydraulic functional surface, wherein the decoupling unit is passively actuated in a restoring direction via a second hydraulic functional surface with a restoring force
Data Source
AI summary
The disclosure relates to a method for actuating a decoupling unit in a powertrain which comprises at least one driven axle. The aim of the disclosure is to simplify the actuation of the decoupling unit. This is achieved in that the decoupling unit is passively actuated in an actuation direction using an actuation force, which is provided in a hydraulic system, via a first hydraulic functional surface, and the decoupling unit is passively actuated in a restoring direction using a restoring force via a second hydraulic functional surface.