Hydrodynamic Retarder Drag Power Reduction via Circulation Flow
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Solution Overview
Problem
Hydrodynamic machines with external working medium circuits face issues with incomplete emptying of the working chamber, especially when partially filled, leading to increased drag power and unwanted power loss in the drive train due to pressure losses during medium flow through outlet bores.
Innovation Solution
The design incorporates additional outlet bores and a circulation flow system with a return line and tap openings to bypass the annular duct, allowing for easier emptying and reducing drag power by diverting working medium from the chamber, even at low pressures, using valves and an orifice plate to control the flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If outlet bores are used to empty the working chamber, then the working medium can be discharged from the chamber, but pressure losses in the outlet bores prevent complete emptying when the chamber is partially filled
Solution Approach 1:
The invention divides the single outlet path into multiple parallel outlet bores distributed over the circumference of the stator. This segmentation increases the total flow capacity and reduces the pressure loss in each individual bore, enabling more effective emptying of the working chamber even when partially filled.
Solution Approach 2:
The invention adds a circumferential dimension to the outlet bores arrangement, distributing them around the entire circumference of the stator rather than using a single centralized outlet. This dimensional expansion creates multiple parallel flow paths that collectively reduce pressure losses and improve emptying efficiency.
2Power
If the working chamber is partially filled to reduce drag power, then power transmission can be controlled, but incomplete emptying leads to residual torque and unwanted power loss
Solution Approach 1:
Multiple outlet bores are distributed around the stator circumference, creating numerous parallel discharge paths. This segmentation allows the working medium to be efficiently removed from the working chamber, minimizing residual quantities that would otherwise generate unwanted residual torque and power loss.
Solution Approach 2:
The invention changes the flow parameters by providing multiple outlet paths with reduced individual pressure losses. This enables the working chamber to be more completely emptied, allowing better control over the residual working medium quantity and thus optimizing the power transmission characteristics while minimizing harmful residual torque.
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 enables extensive emptying of the working chamber and minimizes drag power across all speeds, preventing residual torque and power loss in the drive train, while maintaining efficient power transmission during activation.
Implementation Method 1
the working medium located in the working chamber or on the rear side of the impeller is advantageously thrown radially outwards via the rotating bladed primary wheel (also the secondary wheel in the case of a hydrodynamic coupling) and hits the at least one tapping opening
Implementation Method 2
a bladed primary wheel (1) and a bladed secondary wheel (2), which together form a toroidal working space (3) that can be filled with working medium from an external working medium circuit (4)
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a hydrodynamic machine, particularly a retarder, having an external operating medium circuit (4), comprising - a bladed primary wheel (1) and a bladed secondary wheel (2) which together form a torus-shaped operating chamber (3). The invention is characterized by the following features: - having at least one pickup opening (8) arranged on or outside the operating chamber (3) which is connected in a flow directing manner to the operating chamber (3) or a secondary chamber of the hydrodynamic machine and at least one filling channel (10) which opens into a region of relatively low operating medium pressure within the hydrodynamic machine and is connected in a flow directing manner to the operating chamber (3); wherein - the at least one pickup opening (8) and the filling channel (10) are connected to each other in an operating medium conducting manner by means of a return line (11) outside the external operating medium circuit (4) such that the operating medium flows out of the at least one pickup opening (8) into the filling channel (10) and into the operating chamber (3) therefrom.