Hydrodynamic Retarder Idle Pump Residual Medium Control
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Solution Overview
Problem
Hydrodynamic retarders experience significant power losses during non-braking operations, especially at high speeds, due to the transmission of torque between impellers, and existing solutions are complex and costly, involving separate cooling circuits and inefficient medium management.
Innovation Solution
A method and design for a hydrodynamic retarder that uses an idle pump to maintain a constant residual amount of working medium in the chamber during non-braking operations, minimizing losses by pumping medium into the chamber and ensuring optimal residual amounts independent of speed, with a separate cooling circuit that shares heat exchangers with the braking operation circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the working chamber is emptied during non-braking operation to reduce idling losses, then power losses are reduced, but torque transmission between impellers cannot be completely prevented
Solution Approach 1:
The patent changes the parameter of working medium quantity in the working chamber from completely empty to a controlled residual amount. By maintaining an optimal residual quantity of working medium, the system achieves minimal torque transmission while keeping idling losses acceptable, thus resolving the contradiction between reducing power losses and preventing torque transmission.
2Temperature
If a separate cooling circuit is provided for non-braking operation, then residual working medium can be cooled, but device complexity and cost increase
Solution Approach 1:
The patent makes the cooling circuit universal by using the same heat exchanger for both braking and non-braking operations. The braking operation circuit and non-braking operation circuit share the same cooling infrastructure, eliminating the need for separate cooling systems and reducing device complexity while still providing adequate cooling for the residual working medium.
3Loss of energy
If the working chamber is emptied completely during non-braking operation, then idling losses are minimized, but the system becomes sensitive to speed variations and requires complex control
Solution Approach 1:
The patent implements a self-regulating mechanism where the residual working medium in the working chamber automatically adapts to speed variations. The optimal residual quantity maintains sufficient lubrication and cooling without requiring active control systems, sensors, or actuators to adjust the working medium quantity dynamically, thus reducing control complexity while maintaining energy efficiency.
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 no-load losses and maintains a consistent residual medium level, minimizing the need for separate cooling systems and reducing production and control complexity, while maintaining low idling losses across varying speeds.
Implementation Method 1
In non-braking mode, an idle pump is used to pump working medium into the working chamber of the hydrodynamic retarder in order to set the predetermined remaining quantity
Implementation Method 2
Hydrodynamic retarders have a working chamber that can be filled with a working medium in order to hydrodynamically transmit torque from a driven primary impeller (rotor) to a stationary secondary impeller, which is why it is also called the stator
Implementation Method 3
an external circuit, in which the working medium discharged via the outlet is cooled in a heat exchanger
Data Source
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AI summary
The invention relates to a method for controlling the power transmission of a hydrodynamic retarder, comprising a circulating rotor having vanes and a stator having vanes or a counter-rotating rotor having vanes circulating in the opposite rotational direction to the rotor, which together form a working chamber that can be filled with operating medium by means of an inlet and that can be emptied by means of an outlet, wherein the working chamber is filled in a brake operation with operating medium and a brake torque is generated with the hydrodynamic retarder and, in a non-braking operation, the working chamber is emptied to a specific residual amount of operating medium and substantially no brake torque is generated with the hydrodynamic retarder. The invention is characterised by the following step: In the non-braking operation, by means of an idling pump, operating medium is conveyed from an operating medium reserve, which is provided outside the working chamber in an operating medium reserve tank, into the working chamber of the hydrodynamic retarder for the adjustment of the residual amount.