Hydraulic Assembly with Opposing Flow Circuits

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Solution Overview

Problem

Existing hydraulic assemblies for utility vehicles, such as agricultural vehicles, face inefficiencies in energy use due to high pressure drops in common line sections, leading to increased drive power requirements and slow temperature stabilization of hydraulic fluid, especially during cold starts and varying cooling demands.

Innovation Solution

The hydraulic assembly features two interconnected circuits with opposite flow directions in a common piping section, allowing throughput to differ instead of summing, reducing energy consumption by minimizing pressure drop and enabling quicker temperature stabilization through strategic cooler placement and directional control valves for adaptive fan operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If both hydraulic circuits share a common line section with pumps operating in the same direction, then the system structure is simple, but the pressure drop increases and drive power consumption increases

Engineering Contradiction:

Improvesystem structureVSAvoidpressure drop

Core Design Contradiction:

Device complexityVSLoss of energy

Solution Approach 1:

The patent applies the inversion principle by making the second pump operate in the opposite rotation direction compared to the first pump. This causes the pumps to generate opposing flow directions in the common line section, transforming the additive throughput (S1+S2) into a differential throughput (S1-S2), thereby reducing pressure drop and energy loss.

Inventive Principle:

Principle #13The other way round (Inversion)

2Temperature

If the cooler is placed upstream of the common line section, then hydraulic fluid is cooled effectively, but the second pump must overcome additional pressure drop through the cooler

Engineering Contradiction:

Improvehydraulic fluid temperatureVSAvoiddrive power

Core Design Contradiction:

TemperatureVSLoss of energy

Solution Approach 1:

The patent positions the cooler downstream of the common line section, leveraging the opposite rotation direction of the second pump to create a flow path where hydraulic fluid passes through the cooler without requiring the second pump to overcome the cooler's pressure drop, thus reducing energy consumption while maintaining effective cooling.

Inventive Principle:

Principle #13The other way round (Inversion)

3Ease of operation

If the second pump operates in the same direction as the first pump, then the system configuration is straightforward, but the throughput in the common line section is the sum of both pumps leading to high pressure drop

Engineering Contradiction:

Improvesystem configurationVSAvoiddrive power

Core Design Contradiction:

Ease of operationVSPower

Solution Approach 1:

The patent inverts the rotation direction of the second pump relative to the first pump, transforming the throughput relationship from additive (S1+S2) to differential (S1-S2) in the common line section. This reduces the net throughput and associated pressure drop, thereby lowering the drive power requirement while maintaining a relatively simple system configuration.

Inventive Principle:

Principle #13The other way round (Inversion)

4Loss of energy

If the cooler is placed downstream of the common line section, then the second pump operates with reduced pressure drop, but hydraulic fluid may overheat during continuous operation

Engineering Contradiction:

Improvepressure dropVSAvoidhydraulic fluid temperature

Core Design Contradiction:

Loss of energyVSTemperature

Solution Approach 1:

The patent employs a directional control valve to dynamically switch the cooler's position in the hydraulic circuit. During cold start, the cooler is positioned to allow rapid heating; during continuous operation, it is repositioned to cool the hydraulic fluid, adapting the system's thermal management to varying operational conditions.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent uses periodic action by implementing a control strategy that switches the cooler's position based on operational phases: during cold start, the cooler is bypassed to allow rapid heating, and during continuous operation, it is activated to prevent overheating, creating a periodic thermal management cycle.

Inventive Principle:

Principle #19Periodic action

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 configuration enhances energy efficiency by reducing drive power needs and ensuring efficient fluid circulation, allowing for adaptive fan operation and improved cooling performance across varying conditions.

Implementation Method 1

a cooler for hydraulic fluid circulating in the first hydraulic circuit

Methodology Applied

Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 2

the power required to maintain the fluid flow in the common conduit section is proportional to the square of the throughput

Methodology Applied

Scientific EffectPressure drop: Pressure Drop

Data Source

PatentEP2320095B1Hydraulic assembly

Publication Date: 2017.04.12 CLAAS SELBSTFAHRENDE ERNTEMASCHINEN GMBH

AI summary

The hydraulic building group has a hydraulic system, in which a pump (3), a control drive (4) of a power steering, a radiator (6) for hydraulic fluid circulating in the hydraulic system and a reservoir (1) are connected in row. Two hydraulic systems have circulation directions moving in opposite directions in a common line section (15). An independent claim is also included for a commercial motor vehicle.