Injector Cooling via Cylinder Head Bore Integration

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Solution Overview

Problem

Conventional methods of fuel-to-coolant separation around the injector nozzle in internal combustion engines are inefficient, leading to elevated nozzle tip temperatures and reliability issues due to indirect heat transfer, which can cause spray hole coking, nozzle carboning, and cavitation.

Innovation Solution

Direct physical contact between engine coolant and the injector nozzle assembly is established by forming an engine coolant passage in the cylinder head that opens into and is fluidly connected to the injector mounting bore, eliminating the need for a separate coolant and fuel separation feature, thereby enhancing heat transfer and simplifying the manufacturing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separate coolant and fuel separation feature is used, then physical separation of engine coolant and injection fuel is achieved, but device complexity increases and manufacturing difficulty increases

Engineering Contradiction:

Improvephysical separation of coolant and fuelVSAvoidseparate coolant and fuel separation feature

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The mounting bore and coolant passage are merged into a single integrated structure in the cylinder head. The coolant passage opens directly into the mounting bore, eliminating the need for separate separation features. This integration achieves both cooling function and fluid separation while reducing device complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The mounting bore serves multiple functions: it provides the interface for installing the injector and simultaneously serves as the coolant passage opening. This multi-functionality eliminates the need for dedicated separate features, reducing complexity while maintaining reliability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If indirect heat transfer is used, then physical separation of coolant and fuel is maintained, but heat transfer efficiency decreases leading to elevated nozzle tip temperatures

Engineering Contradiction:

Improvephysical separation of coolant and fuelVSAvoidnozzle tip temperature

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The mounting bore acts as an intermediary structure that allows direct coolant contact with the injector while maintaining separation from the fuel injection path. The coolant flows through the mounting bore and contacts the injector outer surface, providing efficient heat transfer without compromising fuel separation.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Temperature

If direct coolant contact with injector is implemented, then heat transfer efficiency is enhanced, but manufacturing complexity increases

Engineering Contradiction:

Improveheat transfer efficiencyVSAvoidmanufacturing complexity

Core Design Contradiction:

TemperatureVSEase of manufacture

Solution Approach 1:

By combining the coolant passage with the mounting bore structure, the design eliminates the need for separate machining operations or assembly steps. The integrated structure can be manufactured as a single piece or with simpler operations, reducing manufacturing complexity while achieving direct coolant contact for efficient heat transfer.

Inventive Principle:

Principle #5Merging (Combining)

4Ease of manufacture

If conventional coolant passage design is used, then manufacturing is simpler, but cooling effectiveness is reduced leading to coking and cavitation

Engineering Contradiction:

Improvecoolant passage design simplicityVSAvoidcooling effectiveness

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The coolant passage is segmented into two functional zones: the mounting bore section that provides structural support and injector mounting, and the coolant flow section that provides cooling. This segmentation allows each zone to be optimized for its specific function while maintaining manufacturing simplicity through integrated construction.

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

This arrangement effectively lowers nozzle tip temperatures by 60-70° C compared to conventional designs, improving reliability and reducing the risk of coking and cavitation, while also reducing engine costs and increasing power density by ensuring effective cooling of the nozzle assembly.

Implementation Method 1

The engine coolant passage opens into, and fluidly connected to, the mounting bore to cause coolant in the coolant passage to contact the outer surface of the injector retainer

Methodology Applied

Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

engine coolant passage to receive engine coolant to remove heat from the cylinder head

Methodology Applied

Scientific EffectConvection: Convection

Data Source

PatentUS9080540B2Engine with injector mounting and cooling arrangement

Publication Date: 2015.07.14 CUMMINS INTELLECTUAL PROPERTY INC

AI summary

An internal combustion engine is provided including an injector having an injector body including a nozzle assembly having an annular outer surface. A cylinder head includes an injector mounting bore to receive the injector, and a lower sealing portion. The engine also includes an engine coolant passage formed in the cylinder head to receive engine coolant to remove heat from the cylinder head. The engine coolant passage opens into, and is fluidly connected to, the mounting bore to cause coolant in the coolant passage to contact the annular outer surface of the nozzle assembly. A lower seal is positioned between the lower sealing portion and the nozzle assembly to form a fluid seal.