Cylinder Head Cooler for Dynamic EGR Gas Temperature Control

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Solution Overview

Problem

Internal combustion engines face challenges in dynamically managing pollutant emissions, particularly NOx peaks, due to the inability of existing exhaust gas recirculation strategies to quickly switch on or off during rapid load changes, and the high temperature of residual gas in the intake manifold reducing NOx reduction potential and increasing particle concentration.

Innovation Solution

A cooler is strategically placed between the intake manifold and the cylinder head to cool recirculated exhaust gas, with multiple intake ports and a partitioned cooler design that separates the cooling volume to optimize residual gas routing and cooling capacity, allowing for individual control of each cylinder and cycle, and utilizing cooling elements like fins and baffles for enhanced cooling performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If residual gas is stored upstream in the intake manifold for internal EGR, then NOx reduction is achieved, but the high temperature of the residual gas reduces NOx reduction potential and increases particle concentration

Engineering Contradiction:
ImproveNOx emissionsVSAvoidresidual gas temperature
Core Design Contradiction:
Object-generated harmful factorsVSTemperature

Solution Approach 1:

A cooler is introduced as an intermediary component between the intake manifold and the cylinder head to cool the recirculated exhaust gas. The cooler has a cooling medium channel that allows cooling medium to flow through, creating a heat exchange surface that reduces the temperature of the residual gas before it enters the combustion chamber, thereby improving NOx reduction potential and reducing particle concentration.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The cooler is divided into multiple cooling sections with partition walls that separate different cooling zones. Each cooling section can be independently controlled, allowing selective cooling of residual gas for different cylinders. This segmentation enables precise temperature control and optimizes the cooling effect for each combustion chamber.

Inventive Principle:
Principle #1Segmentation

2Object-generated harmful factors

If external EGR or conventional internal EGR is used, then NOx reduction is achieved, but the system cannot switch on or off quickly enough in dynamic operation, causing high NOx peaks during load jumps

Engineering Contradiction:
ImproveNOx emissionsVSAvoidresponse speed of EGR switching
Core Design Contradiction:
Object-generated harmful factorsVSSpeed

Solution Approach 1:

The cooler is designed with variable geometry elements including movable partition walls and adjustable cooling medium flow rates. These dynamic components allow the cooling system to adapt quickly to changing engine load conditions, enabling rapid switching between different cooling modes and achieving fast response times during transient operation and load jumps.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The cooler pre-cools the residual gas during the intake phase before it enters the combustion chamber. By performing the cooling action in advance during the intake stroke, the system prepares the residual gas at the optimal temperature for NOx reduction, enabling quick response to load changes without requiring delayed activation of the EGR system.

Inventive Principle:
Principle #10Preliminary action

3Object-generated harmful factors

If a cooler is added to cool recirculated exhaust gas, then pollutant emissions are reduced, but device complexity increases

Engineering Contradiction:
Improvepollutant emissionsVSAvoidcooling system complexity
Core Design Contradiction:
Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The cooler is integrated directly into the cylinder head structure, merging the cooling function with the existing engine component. The cooling medium channels are formed within the cylinder head material, and the partition walls are incorporated into the head structure, eliminating the need for separate external cooling devices and reducing overall system complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cooler serves multiple functions: it cools recirculated exhaust gas for NOx reduction, acts as part of the cylinder head cooling system, and provides structural support for the intake ports. The cooling medium channels also serve as flow passages for both coolant and recirculated gas, combining multiple functions into a single integrated component.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 effectively reduces pollutant emissions by cooling recirculated exhaust gas, achieving a soot-NOx trade-off with improved cooling performance and adaptability to dynamic engine state changes, comparable to external EGR while maintaining low inertia and individual control for each cylinder and cycle.

Implementation Method 1

a cooler (36) is arranged and designed between the intake manifold (34) and the cylinder head (28) in such a way that the air flowing out of the intake manifold (34) flows through the cooler (36) into at least one intake port (30, 32)

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 2

the cooler has at least one cooling medium channel for a cooling medium to flow through

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

a partition (40) divides the cooler (36) into a first volume (42) and a second volume (44)

Methodology Applied
Scientific EffectFluid separation:

Implementation Method 4

cooling elements like fins and baffles for enhanced cooling performance

Methodology Applied
Scientific EffectHeat dissipation: Fin

Data Source

PatentEP2278138B1Combustion engine and method for operating a combustion engine
Publication Date: 2014.04.16 VOLKSWAGEN AG
  • EP2278138B1 patent drawingFigure 1
  • EP2278138B1 patent drawingFigure 2~4
  • EP2278138B1 patent drawingFigure 5~6

AI summary

The engine has inlet channels formed in a cylinder head (28) of an operating cylinder. A suction tube (34) for combustion air is connected with the inlet channels of the operating cylinder. A cooler (36) is arranged between the suction tube and the cylinder head such that the combustion air from the suction tube flows into the inlet channels through the cooler. The two inlet channels are designed as a filling channel (32) and a swirl duct (30). A partition is formed in the cooler that exhibits a cooling agent channel for a cooling agent that is selected from one of water, gas or oil. An independent claim is also included for a method for operating an internal-combustion engine.