Compensation container for coolant circuits with different temperature level and pressure addition

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Solution Overview

Problem

Expansion tanks for cooling systems with multiple circuits at different temperatures face challenges in rapid pressure build-up and equalization while preventing coolant mixing and heat transfer, leading to inefficiencies and potential component damage.

Innovation Solution

A coolant expansion tank with partitioned chambers and strategically placed passage openings for coolant and air exchange, along with a dual air chamber system and pressure valves, allows for rapid pressure equalization and coolant distribution between circuits while minimizing heat transfer and coolant mixing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the expansion tank volume is designed to be large to accommodate coolant expansion at maximum temperature, then the coolant storage function is improved, but the pressure build-up time increases and cavitation risk increases

Engineering Contradiction:
Improvecoolant storage capacityVSAvoidpressure build-up time
Core Design Contradiction:
Quantity of substanceVSLoss of time

Solution Approach 1:

The expansion tank is divided into multiple chambers (first chamber, second chamber, third chamber) separated by partitions. Each chamber can independently store coolant and contribute to pressure build-up, allowing the system to maintain large total storage capacity while enabling faster pressure response through distributed volume compression

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A compressible foam element is introduced as an intermediary between the coolant chambers and the air chamber. This foam element can be compressed to rapidly build pressure when coolant expands, while still allowing the large expansion tank volume to accommodate maximum coolant expansion without delaying pressure build-up

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If a single expansion tank is used for multiple cooling circuits to consolidate components and enable air-side pressure equalization, then device complexity is reduced and energy efficiency is improved, but coolant mixing and heat transfer between circuits occurs

Engineering Contradiction:
Improvenumber of expansion tanksVSAvoidcoolant heat transfer and mixing
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The expansion tank is segmented into multiple coolant chambers (first chamber for high-temperature circuit, second chamber for low-temperature circuit) separated by heat-insulating partitions. This physical segmentation prevents coolant mixing and heat transfer between circuits while maintaining a single consolidated expansion tank structure for component consolidation and air-side pressure equalization

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different chambers within the expansion tank are assigned different thermal characteristics through heat-insulating partitions and localized insulation measures. This allows each chamber to maintain its specific temperature level appropriate for its connected cooling circuit, preventing harmful heat transfer while benefiting from the unified tank structure

Inventive Principle:
Principle #3Local quality

3Reliability

If the expansion tank is pressurized quickly to prevent cavitation, then pump efficiency is maintained, but the risk of excessive pressure build-up increases

Engineering Contradiction:
Improvepump cavitation preventionVSAvoidsystem pressure
Core Design Contradiction:
ReliabilityVSStress or pressure

Solution Approach 1:

The system uses a pressure-regulating valve to dynamically adjust and maintain the pressure within a specific range (0.5 to 1.5 bar). This parameter control ensures rapid pressure build-up sufficient to prevent cavitation while preventing excessive pressure that could damage components

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

A level sensor detects the coolant level in the expansion tank and provides feedback to the control unit. The control unit uses this information to regulate the pressure-regulating valve, creating a closed-loop control system that maintains pressure within safe limits while preventing cavitation

Inventive Principle:
Principle #23Feedback

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

Enables rapid pressure build-up and equalization between cooling circuits, prevents coolant mixing, and maintains efficient operation by allowing for coolant and additive exchange while reducing heat transfer between circuits.

Implementation Method 1

the first air chamber (L1) enables a rapid pressure build-up in the cooling system with only a small air volume to be compressed

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

pressure equalization between the different systems

Methodology Applied
Scientific EffectPressure equalization: Pressure Gradient

Implementation Method 3

a second pressure relief valve (6b) is attached to the second air chamber (L2) and is designed for a relative opening pressure that corresponds to a pressure difference between the relative opening pressure of the first pressure relief valve (6a) and a predetermined increased relative opening pressure

Methodology Applied
Scientific EffectPressure regulation: Pressure Gradient

Implementation Method 4

The partition (3a) separating the first and second cooling chambers (K1, K2) from one another is designed to be heat-insulating

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 5

The first overflow connection (5a) opens into the first air chamber (L1) in a lower area, and a second overflow connection (5b) opens into the second air chamber (L2) in a lower area

Methodology Applied
Scientific EffectGravity flow: Gravitation

Data Source

PatentEP3521584B1Compensation container for coolant circuits with different temperature level and pressure addition
Publication Date: 2024.01.17 MAN TRUCK & BUS SE
  • EP3521584B1 patent drawingFigure 1
  • EP3521584B1 patent drawingFigure 2
  • EP3521584B1 patent drawingFigure 3

AI summary

The invention relates to an expansion tank for coolant in a cooling system with at least two cooling circuits operating at different temperature levels. To achieve rapid pressure build-up in all connected cooling circuits while simultaneously minimizing heat transfer between them, an expansion tank divided into separate chambers by partitions is provided. This tank comprises at least two coolant chambers connected on the coolant and air sides, and a series connection of at least two air chambers for rapid pressure build-up by means of pressure addition.