Hydraulic System for Hydrodynamic Retarder Torque Control

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Solution Overview

Problem

Existing hydrodynamic machines lack efficient adjustability of braking power, leading to suboptimal temperature control and increased hydraulic resistance, maintenance, and economic inefficiencies.

Innovation Solution

An electrohydraulic system with a pressure control valve, a pump capable of two operating states, and a line system that includes a switching valve and bypass lines to regulate braking torque and volume flow, reducing hydraulic resistance and improving system security, maintenance, and economy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a pressure control valve is used to regulate braking torque, then braking power adjustability is improved, but device complexity increases

Engineering Contradiction:
Improvebraking power adjustabilityVSAvoidhydraulic system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

A pressure control valve is introduced as an intermediary component between the pump and the working chamber. This valve mediates the pressure regulation function, allowing precise control of braking torque by modulating the pressure of working medium supplied to the working chamber, thereby improving braking power adjustability while maintaining system modularity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system regulates braking torque by changing the pressure parameter of the working medium through the pressure control valve. By dynamically adjusting the pressure level of the hydraulic fluid supplied to the working chamber, the system achieves continuous variation of braking power without requiring structural changes to the hydrodynamic machine

Inventive Principle:
Principle #35Parameter changes

2Loss of energy

If the pump operates in non-braking mode with minimal resistance, then energy efficiency is improved, but braking effectiveness may be compromised

Engineering Contradiction:
Improvepump resistanceVSAvoidbraking effectiveness
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The pump system is designed with dynamic characteristics that allow it to operate with minimal resistance during non-braking mode for energy efficiency, while automatically providing high pressure output when braking is activated. The pressure control valve works in conjunction with the pump to dynamically switch between these operating states, ensuring both energy efficiency and braking effectiveness

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system pre-conditions the hydraulic circuit by maintaining readiness for braking operation without continuously applying resistance. The pressure control valve is pre-positioned to allow rapid pressure buildup when braking is required, and the bypass lines are configured to enable quick transition from low-resistance operation to high-pressure braking mode

Inventive Principle:
Principle #9Preliminary anti-action

3Temperature

If the working chamber is continuously filled with working medium, then temperature control is improved, but hydraulic resistance increases

Engineering Contradiction:
Improvetemperature controlVSAvoidhydraulic resistance
Core Design Contradiction:
TemperatureVSStress or pressure

Solution Approach 1:

The system applies different hydraulic conditions to different operational requirements. During non-braking operation, the bypass lines allow working medium to flow with minimal resistance for effective cooling. During braking operation, the pressure control valve directs full pressure to the working chamber for torque generation. This spatial and temporal differentiation of hydraulic quality resolves the contradiction between continuous cooling and low resistance

Inventive Principle:
Principle #3Local quality

4Measurement precision

If a complex line system with multiple valves is used, then control precision is improved, but maintenance difficulty increases

Engineering Contradiction:
Improvecontrol precisionVSAvoidmaintenance difficulty
Core Design Contradiction:
Measurement precisionVSEase of repair

Solution Approach 1:

The hydraulic control system is segmented into modular functional blocks: a pressure control valve for torque regulation, bypass lines for alternative flow paths, and a cooler for thermal management. This segmentation allows each component to be independently maintained or replaced, reducing overall maintenance difficulty while preserving control precision through the coordinated operation of discrete modules

Inventive Principle:
Principle #1Segmentation

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

The solution allows for precise control of braking power, reduced hydraulic resistance, enhanced system security, and cost-effectiveness by regulating system pressure proportionally to torque and maintaining low pump resistance in non-braking operations while supporting braking effectively.

Implementation Method 1

a pump, with a volume flow circulation of the working medium through the line system and the working chamber being able to be generated by means of the pump

Methodology Applied
Scientific EffectPump: Pump

Implementation Method 2

the heat generated in both operating modes is dissipated from the working space by means of the working medium and fed to a cooling circuit for cooling in a cooler

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 3

the valve is a pressure control valve, by means of which the braking power or the braking torque can be controlled/regulated

Methodology Applied
Scientific EffectPressure control: Valve

Implementation Method 4

it is necessary to conduct a minimum volume through the working space in order to cool the retarder in non-braking operation as well

Methodology Applied
Scientific EffectThermal energy absorption: Heat Exchanger

Data Source

PatentEP3052350B1Hydraulic system for a hydrodynamic machine
Publication Date: 2020.07.08 VOITH PATENT GMBH
  • EP3052350B1 patent drawingFigure 1~2
  • EP3052350B1 patent drawingFigure 3

AI summary

The invention relates to a hydrodynamic machine for producing a braking torque, in particular a hydrodynamic retarder, comprising a first blade wheel, in particular a rotor (1), and a second blade wheel, in particular a stator (2), arranged concentrically to the first blade wheel, which blade wheels together from a toroidal working chamber (4), and comprising a hydraulic system. The hydraulic system comprises an open-loop and closed-loop control unit (22), a pump, a heat exchanger, a valve, a working-medium accumulator (10), and a line system. A volumetric flow circulation of the working medium through the line system and the working chamber can be produced by means of the pump. According to the invention, the braking power or the braking torque is controlled in an open-loop/closed-loop manner by means of a pressure control valve.