Hydrodynamic Retarder Evacuation for Torque Reduction

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Water retarder devices in vehicles face challenges in minimizing drag loss and avoiding jerks during connection and disconnection, due to the difficulty in aerating the system without air coming into contact with the coolant, leading to increased acceleration torque and complex components.

Innovation Solution

A hydrodynamic retarder device that reduces pressure in the workspace to or below vapor pressure using a negative pressure generator to evacuate liquid working medium before disconnection, allowing for efficient connection and disconnection without air exposure, utilizing the rotor's rotation to enhance evacuation and reduce clutch load.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the shovel system is filled with air during acceleration phase to reduce acceleration resistance, then acceleration torque is reduced, but air that comes into contact with coolant may adversely impact other vehicle components

Engineering Contradiction:

Improveacceleration torqueVSAvoidair-coolant contact harm

Core Design Contradiction:

ForceVSObject-affected harmful factors

Solution Approach 1:

The system performs preliminary evacuation of the workspace before disconnection occurs. The negative pressure generator activates during the first time period when the rotor is still rotating, removing air and coolant vapor from the workspace before the disconnection event, thereby preventing harmful air-coolant contact during the acceleration phase

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system creates a controlled atmospheric environment in the workspace by using the negative pressure generator to evacuate air and replace it with an inert or controlled atmosphere during the critical acceleration phase, preventing unwanted chemical reactions between air and coolant

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

2Object-affected harmful factors

If water retarder operates with coolant in workspace during disconnection to avoid air contact, then air-coolant contact is prevented, but acceleration torque increases due to liquid mass

Engineering Contradiction:

Improveair-coolant contact preventionVSAvoidacceleration torque

Core Design Contradiction:

Object-affected harmful factorsVSForce

Solution Approach 1:

The system performs preliminary evacuation of the workspace before disconnection. The negative pressure generator activates during the first time period when the rotor is still rotating, removing liquid coolant and air from the workspace before the disconnection event, thereby enabling low acceleration torque operation without harmful air-coolant contact

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system dynamically changes the workspace contents based on operational phase. During connected operation, the workspace contains coolant for braking. During disconnection and acceleration, the workspace is evacuated and maintained empty, allowing the system to adapt its mass characteristics to operational requirements

Inventive Principle:

Principle #15Dynamics

3Productivity

If negative pressure generator is activated during rotor rotation to evacuate workspace, then liquid working medium is removed efficiently, but additional energy consumption is required

Engineering Contradiction:

Improveevacuation efficiencyVSAvoidnegative pressure generator energy

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The negative pressure generator is activated during the first time period when the rotor is still rotating after disconnection, performing the evacuation action in advance while the rotor's residual motion assists the process, rather than waiting until the rotor stops

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses the rotor's own residual rotation energy to assist the evacuation process. The rotor's continued rotation during the first time period creates some centrifugal effect that works together with the negative pressure generator, reducing the total energy required compared to evacuating a completely stationary system

Inventive Principle:

Principle #25Self-service

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 reduces acceleration torque, minimizes wear, and simplifies clutch components, enabling comfortable and efficient connectivity/disconnectivity, while reducing the need for complex components and improving overall efficiency.

Implementation Method 1

the pressure in the workspace is reduced to or below the vapour pressure for the working medium, in order to vacate the workspace of liquid working medium

Methodology Applied

Scientific EffectVapor pressure: Vapour Pressure

Implementation Method 2

utilizing the rotor's rotation to enhance evacuation

Methodology Applied

Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP3107778B1Hydrodynamic retarder device, method for its use and vehicle

Publication Date: 2019.01.02 SCANIA CV AB

Figure 1~2
Figure 3~4
Figure 5

AI summary

Hydrodynamic retarder device (4) comprising: at least one stator (7), in order to, jointly with at least one rotor (8), form a workspace (6) for a working medium and a clutch device for connection and disconnection to/from a power-train (3). The pressure in the workspace (6) is reduced to or below the vapour pressure for the working medium, in order to vacate the workspace of liquid working medium in connection with a disconnection from the power-train. The workspace is kept in an evacuated state until the reconnection of the retarder device (4) with the power-train (3) for subsequent braking operation. The invention also relates to a method and a vehicle.