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Insight into heavy-duty Diesel engine combustion and flow processes

Dr. Edward Long

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Core IC engines Research 18 Full-time Academic Staff:

Prof. Rui Chen – Combustion

Dr Andy Clarke – Combustion, fuels

Prof. Colin Garner – Fluid flow, combustion, after-treatment

Prof. Kambiz Ebrahimi – Engine control

Prof. Graham Hargrave – Fluid flow, optical diagnostics

Dr. Edward Long – Fluid flow, combustion

Paul King – Tribology, dynamics

Dr Salah Ibrahim – CFD, SI combustion

Prof. W. Malalasekera – CFD, combustion, radiation

Dr Byron Mason – Engine control

Prof. Homer Rahnejat – Tribology, dynamics

Dr Ramin Rahmani – Tribology, dynamics

Dr Thomas Steffen – Engine control

Dr Francois Nadal – Fluid flow

Prof. Stephanos Theodossiades – Tribology, dynamics

Henk Versteeg – CFD, heat transfer, after-treatment

Dr Andy Williams – After-treatment, heat transfer, turbocharging

Dr Huayong Zhao – Combustion, optical diagnostics

Plus >35 full-time research staff,

research students and

technicians

Loughborough University

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Largest UK Campus 437 acres

16,500 students; some 4000 studying engineering

7% of UK Chartered Engineers

Research rating: GPA 3.08 Overall

3.37* for Impact, 3.45 for Environment

127 FTE for Mech/Man/Aero/Auto

Dr. Paul GaynorResearch Associate

Loughborough University

Dr. Ruoyang YuanResearch Associate

Loughborough University

Dr. Suji SogbesanResearch Associate

Loughborough University

Tristan KnightPhD Researcher

Loughborough University

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APC3 – Project ASCENT Advanced Systems for Carbon Emission reduction through New Technology

Collaborating across 4 partners to delivertechnology that will enable a majorupgrade of the Caterpillar C4.4 and C7.1heavy-duty diesel engines by 2018:

CO2 reduction Power density growth

Prof. Graham HargravePrinciple Investigator

Loughborough University

Dr. Edward LongCo-Investigator

Loughborough University

Combustion work-stream

Aftertreatmentwork-stream

Dr Vivian PageThermofluids Team Leader

Caterpillar

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Combustion workstream

To generate design tools and understanding that will enable us to develop

advanced combustion systems for the next generation of heavy-duty Diesel engines

Part of our approach to hit the targets of reduced CO2 and increased energy density

Validate and inform simulation tools

Experimental investigation into the following key aspects:

• In-cylinder flow structure• Fuel injection • Mixing and evaporation processes• Combustion

Development of facilities:

• Single cylinder optical engine• Production thermodynamic engine

with endoscopic access

Application of optical diagnostic techniques

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• Single cylinder, fully optical engine with quartz liner and bowditch piston with quartz window

• Non-firing - intake and compression analysis

• Currently fitted with research head

• Fitted with flat top piston, but this can be changed to a simple bowl configuration

• In-Cylinder flow during intake and compression

₋ High speed PIV of flow structure development

₋ High speed PIV of turbulence during compression

• Provides important data for non-reacting model validation

Application

Engine design

Single-cylinder optical engine

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Complete for intake and compression strokes.

• 1.5kHz PIV rate• Independent port blocking

Tumble plane HSPIV at 800rpm and 1000rpm Imaging region

Laser sheetNd:YAG /

Nd: YLF Laser

Top of image in line with cylinder head

Intake Valves

Exhaust Valves

Optical engine imaging setup

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Complete for intake and compression strokes.

• 1.5kHz PIV rate• Independent port blocking

Swirl plane HSPIV at 800rpm and 1000rpm

Laser Sheet

TDC

45° CA

90° CA

High Speed camera

Optical engine imaging setup

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Ensemble Mean-Averaged vs. Instantaneous Velocity Vectors 180 °CA – 360 °CA

Compression results 1000 rpm

1.5 kHz data rate = 4 CAD

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Compression and intake – RMS turbulence 1000 rpm

Intake Compression

1.5 kHz data rate = 4 CAD

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Simulation results: RMS Comparison

Central tumble plane

Standard k-epsilon

k-epsilon + dynamic

coefficients

RNG k-epsilon

Rapid distortion

RNG k-epsilon

RNG - 1.6

Experimental data (PIV)

Caterpillar simulation study, curtesy of Tushar Shetaji & Vivian Page

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Turbulence – Scale, energy and quantification

Turbulence scale (spatial and temporal) is important

Turbulent structures as they interact with a surface

Turbulence effects key parameters:

• Mixing• Fuel evaporation• Rates of flame propagation• Heat transfer to walls and surfaces

Flame propagation through a turbulent field

This in turn impacts:

• Performance• Emissions• Cooling system requirements• Durability

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Proper Orthogonal Decomposition (POD) of PIV data

=+ +

..+..…+

Mean Mode 1

Mode 2

Mode 19 Mode 70

Energy content (relative) of POD modes at individual crank angles

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Endoscopic access into the Cat® C4.4 ACERT engine for combustion analysis

2. Endoscope introduced through direction of the glow-plug hole

1. Endoscope introduced through the end of the cylinder head – endoscope and pressure window can be swapped for a light guide

Intake portCoolant passage

Coolant passage

1. Access through end of cylinder head

2. Access through glow-plug channel

Piston bowl

Secondary access point for image capture

Camera/mount position (glow plug access)

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Cylinder head

Endoscopic access into the Cat® C4.4 ACERT engine for combustion analysis

Early combustion imagingCold start1000 rpm low load6400 frames/s recording

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Endoscopic optical

techniques

Objectives

Direct Imaging • Spray motion; interaction between fuel jet and in-cylinder flow

• Fuel jet-wall interaction• Combustion event - ignition timing, locations

Two-colour soot pyrometry • Soot/flame temperature• Soot concentration

Chemiluminescence

imaging

• Time-resolved heat release rate• Flame lift-off length• Light-based ignition delay and sites• Whole field technique for engine application

Endoscopic data – further analysis

OH* Chemiluminescence of methane/air flame showing heat release region

Two-colour pyrometryoptical setup

Photo of burner test rig

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Summary

The use of experimental investigation and validated simulation tools to give valuable insight into Diesel engine combustion and flow processes

The importance of accurate turbulence quantification and simulation

The valuable role of optical techniques when coupled with:

• A single-cylinder optical engine• A production engine with endoscopic access

Development of design tools that will enable us to meetthe challenging demands of future generation IC engines

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Insight into heavy-duty Diesel engine combustion and flow processes

Dr. Edward Long