Secondary Coolant Circuit with Circulating Pump for Engine Thermal Management

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Solution Overview

Problem

The existing coolant circuits in internal combustion engines are inefficient in optimizing cooling and heating of components, as they rely on the speed of the coolant pump, leading to increased energy consumption and fuel usage, especially when additional components like air compressors or transmission oil coolers require enhanced cooling capacity, which strains the energy balance.

Innovation Solution

The implementation of a secondary coolant circuit with an additional circulating pump, which is electrically or pneumatically driven and can be controlled independently of the main coolant pump, allowing for optimized cooling or heating of components based on their specific requirements, reducing the load on the main coolant pump and enhancing energy efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If the coolant pump speed is increased to provide sufficient cooling for additional components in the auxiliary coolant circuit, then the cooling capacity for these components is improved, but the energy consumption and fuel usage increase

Engineering Contradiction:
Improvecooling capacityVSAvoidenergy consumption
Core Design Contradiction:
TemperatureVSUse of energy by moving object

Solution Approach 1:

The patent divides the coolant circulation system into a main coolant circuit for the combustion unit and at least one auxiliary coolant circuit for additional components. Each circuit can be controlled independently, allowing the auxiliary circuit to receive coolant flow optimized for its specific thermal requirements without unnecessarily increasing the pump speed for the entire system, thereby reducing overall energy consumption.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces controllable flow resistance elements (such as thermostatic valves or electronically controlled valves) in the auxiliary coolant circuit that can dynamically adjust the coolant flow based on the thermal load of additional components. This dynamic control allows the system to provide sufficient cooling capacity only when and where needed, avoiding continuous high pump speed operation and reducing energy consumption.

Inventive Principle:
Principle #15Dynamics

2Reliability

If the coolant pump is mechanically coupled to the crank mechanism to ensure sufficient coolant flow for all components, then the reliability of cooling is improved, but the device complexity and fuel consumption increase

Engineering Contradiction:
Improvecooling reliabilityVSAvoidpump control system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the coolant distribution into separate main and auxiliary circuits with independent flow control. This segmentation allows each circuit to be optimized for its specific requirements while maintaining overall system reliability, as the mechanical coupling ensures baseline flow reliability while the auxiliary circuit's controllable resistance elements provide additional reliability for specific thermal management needs.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces controllable flow resistance elements as intermediaries in the auxiliary coolant circuit. These elements mediate between the mechanically coupled pump (which provides reliable baseline flow) and the additional components (which require variable cooling). The intermediaries allow precise control of coolant distribution without requiring complex direct control of the pump itself, thus maintaining reliability while managing complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If a single coolant pump serves both the main coolant circuit and auxiliary coolant circuit, then the device complexity is reduced, but the adaptability to different thermal loads of individual components is limited

Engineering Contradiction:
Improvepump systemVSAvoidthermal load adaptation
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent divides the coolant distribution system into separate main and auxiliary circuits that branch from the common pump output. This segmentation allows independent control of coolant flow to different components through controllable flow resistance elements in the auxiliary circuit, providing adaptability to different thermal loads while maintaining a relatively simple single-pump architecture.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces dynamically controllable flow resistance elements in the auxiliary coolant circuit that can adjust coolant flow based on the thermal load requirements of additional components. This dynamic control capability allows the system to adapt to varying thermal conditions of individual components without requiring multiple pumps, thus maintaining device simplicity while achieving high adaptability.

Inventive Principle:
Principle #15Dynamics

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 allows for improved cooling and heating of components with reduced fuel consumption by decoupling the cooling capacity from the engine speed, enabling more efficient management of coolant flow based on the thermal loads of individual components, thereby optimizing energy use and reducing the strain on the main coolant pump.

Implementation Method 1

a coolant fluid is pumped with a coolant pump in a coolant circuit through coolant channels of the combustion unit or the engine block

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

The coolant heated up in this way is pumped through external heat exchangers and cooled down again there

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 3

The coolant heated up in this way is pumped through external heat exchangers and cooled down again there

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 4

cool additional components of the internal combustion engine or of a motor vehicle having the internal combustion engine as heat sources and/or to heat them as heat sinks

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentEP3412885B1Combustion engine with coolant circuit
Publication Date: 2023.06.07 MAN TRUCK & BUS SE
  • EP3412885B1 patent drawingFigure 1~2
  • EP3412885B1 patent drawingFigure 3~4

AI summary

The invention relates to an internal combustion engine (1), in particular for a motor vehicle, with a coolant circuit (2) operated by means of a coolant pump (5) as the main coolant circuit (3) for cooling a combustion unit (7a) of the internal combustion engine (1), and with at least one secondary coolant circuit (4) branching off from and rejoining the main coolant circuit (3) for cooling at least one further heat source and/or for heating at least one heat sink as at least one further component of the internal combustion engine (8) or of a motor vehicle comprising the internal combustion engine, in particular for cooling an air compressor (15) and/or a transmission oil cooler (16) and/or a heating heat exchanger (17), wherein the coolant pump (5) is coupled directly or indirectly to the crankshaft of the internal combustion engine (8) for a pump drive.According to the invention, in the at least one secondary coolant circuit (4) at least one circulation pump (18) adapted to the cooling or heating requirements of at least one associated component (15, 16, 17) is arranged in addition to the coolant pump (5) of the main coolant circuit (3).