Proposal to establish a laboratory for combustion studies

Jayr de Amorim Filho Brazilian Bioethanol Science and Technology Laboratory

SCRE – Single Cylinder Research Engine Laboratory

OUTLINE Requirements, Project Goals and Solutions Proposals Research tasks and technologies Single Cylinder Test bed and Engines Research tools for combustion studies with SCREs

Project Goals and Suggested Solutions

PROJECT GOALS

1. Development of Spark Plugs – project design ; effects on ignition, plasma and flame development

2. Investigation of deposits on spark plug and in the engine

3. Emission studies; e.g. NO, OH, HC, CH.

4. Cold start investigations

5. Direct injection spray and evaporation investigations (Injector Development)

Test bed system: SCE, SCTB and peripherals

infrastructure:

mechanical, media,

energy, environment

SCE:

Air: NA

Fuel: Ethanol - Gasoline

ECU: open engine controller

SCTB:

compact test bed with active dyno, test bed controller

Engine conditioning:

external coolant / lube oil supply at regulated temperature and pressure

SCE SCTB shaft

controller SCE

controller SCTB

data data

analyser analyser

interpretation

Optical Instrumen -

tation

analyser

data

controller

Optical access SCE SCTB shaft

controller SCE

controller SCTB

data data

analyser analyser

interpretation

Diagnostic Instrumen -

tation

analyser

data

controller

Optical access

Access to infrastructure:

concrete base floor, cooling water, electric power supply, air in, exhaust out

Peripherals, Diagnostics: to be defined to meet the needs

Project Application Matrix

SCRE – Single Cylinder Research Engine

Considerations for choosing the right components

1. What is the application target?

2. What engine configuration is required for this application? (fuel, injection and combustion

type, naturally aspirated or charged, size, thermodynamic or optical engine)

3. What instrumentation and measurement devices are required for the desired application?

(Imaging, thermodynamics, LIF, gas analysis etc.)

4. What test cell equipment is required for safe operation and measurement?

(conditioning units, fuel measurement, blow by, air mass flow, temperatures and pressures…)

5. What special measurement systems are planned to be used, and what integration is

required? (LIF, combustion analysis, emission…)

6. What are the requirements for the test cell and installation?

7. What trainings are required to operate the equipment safely and achieve the desired

results ?

SCRE – Single Cylinder Research Engine

OUTLINE Requirements, Project Goals and Solutions Proposals Research tasks and technologies to achieve them Introduction to Single Cylinder Test bed and Engines Research tools for combustion studies with SCREs

Spark Plug Development

Goals Investigation of ignition behavior, temperatures and deposits Spark Plug Development Recommended Solutions Development of the spark plug requires operation under realistic conditions including high load and long term operation. For the investigations an optical access through endoscope with high resolution camera for flame investigation or infrared camera for surface temperature investigations can be used.

Schematic of experimental setup

Electrical Parameters for Duty Cycle of 25 %.

10 15 20 25 30 35 40

5500

6000

6500

7000

Pea

k V

olta

ge

(V

)

Duty Cycle (%)

10 15 20 25 30 35 402,2

2,4

2,6

2,8

3,0

3,2

3,4

3,6

3,8

Pe

ak C

urr

en

t (m

A)

Duty Cycle (%)

Results

Spark Plug Discharge Electrical Characterization

Discharge temperature characterization • The gas temperature was estimated from the rotational spectrum of the SPS of N2 (C3Πu → B 3Πg ) using a comparison between the experimental spectra and the simulated ones.

3310 3320 3330 3340 3350 3360 3370 3380 33900,0

0,2

0,4

0,6

0,8

1,0

Inte

nsity (

a.u

.)

Wavelength (A)

Experimental

Simulated

Trot

=(2058 ± 75) K

Electron density characterization • Determined by Stark broadening on Hα emission line.

654,5 655,0 655,5 656,0 656,5 657,0 657,5 658,0

-20

0

20

40

60

80

100

120

140

160

180

Inte

nsity (

a.u

.)

H, Duty Cycle 40%

Ajuste Voigt

Wavelength (nm)

][10646,011 nmneStark

][119 nmT

PX

g

hressonante

][45,37,0

__ nmPTgWaalsdervan

][1002,2 4 nmNatural

][107,4 4 nmT hDoppler

Broadening Mechanisms

0 1 2 3 4 5 6

4,0x1014

6,0x1014

8,0x1014

1,0x1015

1,2x1015

1,4x1015

1,6x1015

1,8x1015

Ele

ctr

on

de

nsity (

cm

-3)

Time (ms)

ne_D10%

ne_D15%

ne_D20%

ne_D40%

Electron temperature characterization • Determined by Saha equation using Argon emission lines.

748,6 750,5 752,4 754,3

0

200

400

600

800

1000

1200

473,1 475,0 476,9 478,8

0

20

40

60

80

0 1 2 3 4 5 6

17000

17500

18000

18500

19000

19500

20000

20500

Ele

ctr

on

te

mp

era

ture

(K

)

Time(ms)

Te D10%

Te D15%

Te D20%

Te D40%

Thermal imaging + calibration

In-cylinder temperature evaluation

Technical details: Fused silica window,

endoscope with BK7 imaging optics,

B/W camera, 10 ms exposure time in

exhaust / intake stroke.

Direct view onto spark plug.

Endoscope access from pent roof

side

Objects: Spark plug or exhaust valves

Thermal imaging – local sensitivity

Thermocouple on sparkplug: radiation to temperature calibration

500

600

700

800

900

0 1000 2000 3000 4000

Radiation intensity [rel. unit]

Tem

p. [

deg

C]

Window, endoscope and

camera local sensitivity, use

camera calibration device

Thermal image

Radiation to temperature

conversion, use temperature

calibration device

Thermal image……. x local sensitivity field x calibration curve ………yields temperature

field

Temperature field On engine test

bed

18

In-cylinder thermal imaging: example on ignition timing effects

Flame and Plasma Spectroscopy & Imaging

Goals

Analysis of Flame and Plasma properties under real combustion conditions

Recommended Solutions

Flame and Plasma investigations require the best possible access to the spark plug and combustion chamber, and stable conditions for best repeatability and comparability. Therefore the recommended engine is a transparent SCRE with pent roof glass liner (full access to spark plug), piston with glass window and mirror unit (optical access from below) and port fuel injection (MPFI) for stable, homogeneous air-fuel mixture.

Transparent Engine: Example Flame Imaging

Studies of interaction between injection, mixture

formation and combustion with different optical

technologies.

High speed or high-resolution imaging through

glass cylinder liner or piston window, mostly for

studies of wall wetting and dispersed droplets leading

to local sooting combustion.

PLIF studies for investigation of non-reacting as

well as reacting gas and liquid flows in a nonintrusive,

instantaneous flow visualization with high spatial and

temporal resolution.

Ethanol DI Cold Start Investigation

Spray and Injector Analysis

Goals

Analysis and optimization of injection strategies for starting engines with Ethanol at low

temperatures

Recommended Solutions

The critical point of engine starting in low temperature, especially with Ethanol is the

evaporation of the fuel. To find the best timing and strategies for the injection, a SCRE

with glass liner and high pressure direct injection system is required.

Using imaging with high speed cameras, the injection spray and the resulting flame

can be filmed. Since liquid fuel is burning with a much brighter flame, this technique

clearly shows wall wetting and liquid fuel droplets, and can be used to analyse influences

of injection parameters like timing, pressure or injector type on the starting process.

Transparent Engine: Example Spray Imaging

Spray studies to investigate influences of injection timing, injection pressure and injection hardware. Using imaging technologies allows fuel droplet analysis. Using Laser Induced Fluorescense (LIF) allows fuel vapor distribution studies. The active dyno of the SCTB allows motoring the SCRE to conduct spray and vapor formation studies without combustion.

Fuel pressure 4 bar Fuel pressure 40 bar

Big droplets Small droplets

Wall film Significantly reduced wall film

SCRE – Single Cylinder Research Engine Laboratory

OUTLINE Requirements, Project Goals and Solutions Proposals Research tasks and technologies Single Cylinder Test bed and Engines Research tools for combustion studies with SCREs

Single Cylinder Compact Test Bed

Specifications for single cylinder research engines test bed: Completely assembled with engine, active dyno, dyno control and conditioning systems for Engine Very low requirements for facility: - no special foundations or baseplates - only electrical and water supply needed The SCTB can be easily moved with a fork lift Flexible use with different engines , also multi cylinder up to 60kW/200Nm

Single Cylinder Engine and Test Bed Installation and key features

• Modular concept to combine the reliability of standard components with flexibility for specific solutions. • Very low requirements for installation.

Transparent Research Engine with port fuel and direct injection systems

SCRE with pent-roof glass liner and mirror system that allows optical access with cameras and other optical systems like Spectrometry systems or LIF: Flame and spray studies with high resolution or high speed cameras. Studies of injection parameter variation and optimization for reduced wall wetting and optimized mixture formation and combustion. Allows detailed studies of mixture formation and combustion with spectrometry, LIF or other techniques with full optical access to combustion chamber due to the pent-roof glass liner and piston window

Thermodynamic Research Engine with port fuel and direct injection systems

SCRE spark ignited engine for combustion development and research also under high-load, high-speed and long-term operation. Combustion analysis by means of pressured based measurement (indicating) or endoscopic optical access to the combustion chamber. Surface temperature investigations on spark plug and valves with endoscope and infrared camera. High load and simulated turbo-charged operation. Emission trend analysis with FTIR and Online Soot Measurement. Long term operation possible for study of deposits and corrosion.

SCRE – Single Cylinder Research Engine Laboratory

OUTLINE Requirements, Project Goals and Solutions Proposals Research tasks and technologies to achieve them Introduction to Single Cylinder Test bed and Engines Research tools for combustion studies with SCREs

SESAM-FTIR R&D Emission Analyzer with Infrared Spectroscopy

Thermodynamic analysis of combustion: Indicating System and GCA Gas Exchange and Combustion Analysis

Fuel Consumption Measurement Fuel Measurement Systems and Sensors for SCRE

Conclusion

Project management techniques required to build a modern test facility are the same as those for any multidisciplinary laboratory construction. New diagnostics need to be developed for contaminants detection in ethanol. Discharge phase parameters may be characterized using passive and active spectrocopies. Better understanding of combustion and pollutant formation processes in IC engines.