Internal combustion engine emissions - Katedra … · Experimental methods class –engines, vehicles, emissions testing lecture Michal Vojtisek, [email protected], tel, +420

Experimental methods class – engines, vehicles, emissions testing lectureMichal Vojtisek, [email protected], tel, +420 774 262 854 1

Internal combustion engine emissions

MAE, Emissions 1

Overview of pollutants of concern and their production.

Products of the combustion process and their side effects. Global climatic changes, greenhouse gases and greenhouse effect. Particulate matter and its effects on environment and human health. Nitrogen oxides and tropospheric ozone. Air quality in EU cities. Emission abatement through engine design and control. Exhaust aftertreatment. Contribution of high emitters, periodic emissions inspections and in-use measurements.

Emissions measurement

Type approval, research, development, in-use compliance, inspection & maintenance testing. Analyzer range, relative and absolute accuracy, response time, selectivity. Calibration, calibration gases, metrology, traceability of calibration. Detection principles of common analyzers.

Engine and vehicle testing laboratory

Engine and chassis dynamometers, measurement of torque, fuel consumption, air flow, temperatures, pressures, constant volume samplers, online measurement of HC, CO, NOx, CO2, particle number (PN), particle sampling, filter weighing room, management of fuels and calibration and process gases, advanced instrumentation.

Particulate matter, legislation, advanced measurement

Particulate matter measurement – particle mass and number, sample handling.

Advanced measurements – FTIR spectrometers, particle size distributions, sampling for chemical analyses and toxicity assessment.

Real-world emissions and their measurement, real driving emissions (RDE) legislation.

Michal Vojtíšek, [email protected], tel. 774 262 854


Emissions:

Why do we care?


Particulate matter is responsible for 406 thousands, NOx for 72 thousands premature deaths annually in the EU

(traffic accidents for „only“ 39 thousands)


WHO: 7 milions annually worldwide (25.3.2014)http://www.who.int/mediacentre/news/releases/2014/air-pollution/en/

European Environment Agency: 350 thousands annually in the EUhttp://www.eea.europa.eu/media/newsreleases/reducing-the-20ac-45-billion

European Environmental Bureau: 455 thousands annually in the EU – just particles

http://www.eeb.org/EEB/index.cfm/news-events/news/air-pollution-threat-highlighted-at-launch-of-2013-year-of-air/

Czech National Inst. Of Health 2013 – 7-8 thousands annually in CZhttp://apps.szu.cz/svi/hygiena/archiv/h2013-1-02-full.pdf




https://openknowledge.worldbank.org/bitstream/handle/10986/25013/108141.pdf

Economic damages of air pollution in the EUestimated to 5% of GDP (World Bank, 2016)


Near zero-emissions engine technology is here, today.

Yet motor vehicle emissions remain one of the key sources of air

pollution, with major impacts on our environment and on our health.

Why?And what can we do about it?


Near zero-emissions engine technology is here, today.(Locomotive, California)


Near zero-emissions engine technology is here,

today.(Construction machine,

Switzerland)


Despite our efforts towards sustainable transportation…


… we still heavily rely on automobiles with internal combustion engines …


=+

… with detrimental effects on our air quality …


… and detrimental effects on our health.


Formation of pollutants

MAE, Emissions 13

Ideal combustion:

CxHy + (x+y/2) O2 (+ N2+inert) -> x CO2 + y/2 H2O (+ N2+inert)

Real combustion:

• Incomplete oxidation of fuel and lubricating oil:

Hydrocarbons (HC), carbon monoxide (CO), particulate matter (PM)

• Sulfur (SOx) and metals from S and metals in fuel & oil

• Formation of nitrogen oxides (NO and NO2) from N2 and O2 at

high combustion temperatures (Zeldovich mechanism)


Problematic pollutants in engine exhaust

• Particles + secondary aerosol

• NOx + tropospheric ozone

• CO, benzene, lead – no longer a problem

New and emerging problems:

• NO2 - formation in oxidation catalysts

• NH3 - formation in reduction catalysts

• - formation in three-way catalysts when run rich

• Aldehydes – oxygenated fuels (ethanol)

Greenhouse gases

• N2O - NOx reduction catalysts (SCR, LNT)

• CH4 - natural gas engines, LNT catalyst


(Diesel) ICE exhaust particulate matter

Liati A., Dimopoulos P.E., Combustion and Flame 157 (2010) 1658–1670.

• Small particles (units to hundreds of nm) formed by incomplete combustion of fuel and engine lubricating oil and wear metals• Complex mixture of compounds, many known to be carcinogenic• More premature deaths (> 400 K per year in EU) than traffic accidents (< 40 K per year)• One of the most pressing urban environmental problems


Typical diesel exhaust PM size distribution

Kittelson, J. Aerosol Sci. Vol. 29, No. 5/6, pp. 575-588, 1998


B. Alfoldy et al., Aerosol Science 40 (2009) 652—663.

Lung deposition fraction:ET – extrathoracic

TB – tracheobronchialPU – pulmonary

Particle mass median diameter:NM – nucleation mode

AM – accumulation mode

Lung particle capture efficiency


A. Mayer, 12th ETH Conference on Combustion Generated Nanoparticles, Zurich, 2008

Lung particle capture efficiency


< 10 000 #/cm3

10-20 000 #/cm3

20-50 000 #/cm3

> 50 000 #/cm3

0

20

40

60

80

100

7:38 7:42 7:46 7:50 7:54 7:58 8:02 8:06 8:10

UF-CPC-1s

School parking lot (5 s avg)

School entrance (5 s avg)

738 720 #/cm3

thousands of particles per cm3

School entranceSchool entrance

School School parking lotparking lot

School entranceSchool entrance

Major highwayMajor highway

The particles are mostly along the roads!The particles are mostly along the roads!Hey, they are in the parking lot!Hey, they are in the parking lot!

Lots of them!Lots of them!It is all cars!!!It is all cars!!!

Sion Elementary School instrumented walking tour: Where are the particles that we breath?


Neighborhood of Spořilov instrumented walking tour

0

200000

400000

600000

800000

1000000

10:53:00 10:58:00 11:03:00 11:08:00 11:13:00 11:18:00 11:23:00 11:28:00

pa

rtic

les

pe

r c

m3

5-20 nm

5-40 nm

5-100 nm

5-560 nm

HEPA filtered air (zero check)

noise due to

instrument

transport

peaks likely generated

by the passage of

high emitting vehicles

26.3.2014 10:15-13:45

Particle number concentrations

EEPS 5-100 nm

[thousands #/cm3]

14

47

60

6

9

4

4

8

18

12

5

5

3

3

6

7

38

43

9

661

41

110

226

33

195

106

215

100

5

10

20

50

EEPS 5-100 nm

Scale

8-10 C

60% RH

2-6 m/s

““SpoSpořřilov ilov hotspothotspot””::After low-speed travel through congested area of Prague, heavy

trucks accelerate onto a freeway and climb a hill –“reentrainment” of material

deposited in the exhaust system.


Particle concentrations vary, size distributions remain similar Particle concentrations vary, size distributions remain similar near near roadways, and match engine exhaust size distributionsroadways, and match engine exhaust size distributions

SpoSpořřilov, February 2014, mean of 40 normalized distributionsilov, February 2014, mean of 40 normalized distributions

0.00

0.02

0.04

0.06

0.08

0.10

0.12

6 7 8 9 11 12 14 17 19 22 26 29 34 39 45 52 60 70 81 93108124143166191221255294340392453523

particle electric mobility diameter [nm]

no

rma

lize

d p

art

icle

nu

mb

er

co

nce

ntr

ati

on Mean (error bars - st.dev.)

Geometric mean

Median

~ 10 nm~ 10 nm

~ 30~ 30--40 nm40 nm

Vojtíšek et al., NanoCon 2014

Diesel engineDiesel engineRonkko et al., EST 2013Ronkko et al., EST 2013


U Tesca, rozjezd busu nestandardní palivo

35

56

21

31

33

9

77

114

25

3 3

2

15 11

29

27

43

29

30

67

7

30

16 55

13

171

89

492 127

161

50.191

50.192

50.193

50.194

50.195

14.491 14.493 14.495 14.497 14.499 14.501 14.503 14.505 longitude (E)

lati

tud

e

(N)

Morning rush hour May 15

Smoking vehicles

Lawn mowing

Total particle counts, 10-500 nmthousands of particles per cm3

Líbeznice, 15. 5. 2014, morning rush hour


Increased risk of heart attacks as a factor to distance from a densely traveled road

3399 persons, age 45-75, Essen, Germany(A. Mayer, TTM, Switzerland)

Risiko OR

Hoffmann 2006

0

0,5

1

1,5

2

2,5

3

> 200 100-200 50-100 < 50 m

Distanz


Current particulate matter measurement standards might not accurately reflect health effects

x 1,000 x 1,000,000


“Fine particulate matter (PM2,5) is responsible for significant

negative impacts on human health. Further, there is as yet no

identifiable threshold below which PM2,5 would not pose a

risk. As such, this pollutant should not be regulated in the

same way as other air pollutants. The approach should aim at

a general reduction of concentrations in the urban

background to ensure that large sections of the population

benefit from improved air quality. However, to ensure a

minimum degree of health protection everywhere, that

approach should be combined with a limit value, which is to

be preceded in a first stage by a target value.”

(Preambule to 2008/50/EC)

No safe level for particulate matter in the air


Gaseous Emissions

MAE, Emissions 26

• Carbon monoxide (CO) – toxic gas

• Non methane hydrocarbons (NMHC)

• Nitrogen oxides (NOx)

- ground level ozone - smog

• Methane (CH4)

• Carbon dioxide (CO2)

- Greenhouse gases

• Volatile organic compounds (VOC) fuel vapour

• Toxic components, formaldehyde, acetaldehyde, benzene,

acroleine, 1,3-butadiene, and mixtures of gaseous, liquid and

solid organic components formed by diesel fuel combustion in a

compression ignition engines


Nitrogen oxides and ground level (tropospheric) ozone

http://www.stadtentwicklung.berlin.de/umwelt/umweltatlas/ed306_06.htm


U.S. EPA: Climate Change Indicators 2016https://www.epa.gov/sites/production/files/2016-08/documents/climate_indicators_2016.pdf

Global climate changes


https://en.wikipedia.org/wiki/Greenhouse_gas#/media/File:Atmospheric_Transmission.png

Greenhouse effect: spectra of solar vs. Earth radiation



Changes in CO2 concentrations


NOAA, USAhttp://www.esrl.noaa.gov/news/2008/img/co2trend.m.gif

Changes in CO2 concentrations


http://www.usgcrp.gov/usgcrp/Library/nationalassessment/LargerImages/OverviewGraphics/1000YrRecords.jpg

Carbon emissions, CO2 concentrations, global temperature



Climate change induced extreme weather patterns



Effect of different greenhouse gases



Production of greenhouse gases


https://www.ipcc.ch/pdf/assessment-report/ar4/syr/ar4_syr_full_report.pdf

Anthropogenic contribution to greenhouse gas emissions


http://www.eea.europa.eu/data-and-maps/data/data-viewers/greenhouse-gases-viewer

Anthropogenic contribution to GHG emissions (EU-28, 2015):CO2: transport – ground 25,6%, total 33,4%

total GHG: transport - ground 21%, total 27,4%


Emissions:

Reduction by better fuels and technology


Formation of pollutants

MAE, Emissions 39

Ideal combustion:


Real combustion:







Biomass based fuels production and utilization cycle

OilOil--rich

plants

rich plants

Fuel oil

Fuel oil

BIOMASS

BIOMASS

Minerals (ash)Minerals (ash)

COCO22

COCO22

SO

LAR

S

OLA

R

EN

ER

GY

EN

ER

GY

HEATHEAT

ENGINESENGINES


Wang et al., Environ. Res. Lett. 7 (2012) 045905http://iopscience.iop.org/1748-9326/7/4/045905/pdf/1748-9326_7_4_045905.pdf

Embedded fossil carbon & energy balance of fuels


http://www.eea.europa.eu/data-and-maps/figures/overall-well-to-wheel-greenhouse-gas-emissions-of-various-types-of-biofuels-compared-to-reference-fuel/annex-figure-13-term-2005.eps/image_original




Larson, Energy for Sustainable Development, 10, 2, 2006, 109-126.http://francois.catroux.free.fr/CNAM/ENF208-Energie%20et%20developpement%20durable/2008/sdarticle4.pdf



NEB of corn grain ethanol and soybean biodiesel production.

Hill J et al. PNAS 2006;103:11206-11210

©2006 by National Academy of Sciences



Problematic pollutants in engine exhaust

• Particles + secondary aerosol

• NOx + tropospheric ozone

• CO, benzene, lead – no longer a problem

New and emerging problems:

• NO2 - formation in oxidation catalysts

• NH3 - formation in reduction catalysts

• - formation in three-way catalysts when run rich

• Aldehydes – oxygenated fuels (ethanol)

Greenhouse gases

• N2O - NOx reduction catalysts (SCR, LNT)

• CH4 - natural gas engines, LNT catalyst


Emission reduction accomplishments through better technology

Gasoline engines, USA, 70’s-90’sReduction of new car emissions by 96-99%

•unleaded gasoline•closed-loop computer controlled fuel injection

•three-way catalytic converter•low-sulphur diesel

•inspection/maintenance programs

Similar dramatic reductions are being implemented for diesel engines (1980’s-2010’s)


Three-way catalyst (TWC) operation

MAE, Emissions 48

Formation of hydrogen through water gas shift:

CO + H2O <-> CO2 + H2

Reduction of NOx:

H2 / HC / CO + NOx -> N2 + H2O / CO2

Oxidation:

H2 / HC / CO + O2 -> H2O / CO2

Stoichiometric air-fuel ratio needs to be maintained.

Excess oxygen: not enough reductants for NOx

Insufficient oxygen: incomplete oxidation, reduction of NOx to NH3


Low-emissions diesel engines

High-pressure electronically controlled fuel injection

PM reduction on the order of 90%

Diesel particle filters

Particles physically captured and periodically combusted, 90-99.9%

efficiency

Diesel oxidation catalysts

Reduction of organic gases, carbon monoxide, some organic PM

NOx reduction

Improved design and control

Exhaust gas recirculation (EGR)

Selective catalytic reduction (SCR) using a dosed ammonia or urea

solution

Non-selective catalytic reduction using periodic fuel enrichment


Lean NOx trap (LNT) / NOx storage and reduction (NSRC)

MAE, Emissions 50

Alternating lean (1-2 minutes) and rich (several seconds) phases

Lean phase:

Storage of NOx (i.e., BaCO3 -> BaNO3)

Rich phase:

Release of stored NOx & reduction as in three-way catalyst

Downsides and side effects:

Temperature-dependent operation & efficiency

Additional fuel consumption for rich phase

Release of NH3 and N2O


Selective and non-selective NOx reduction

MAE, Emissions 51

Non-selective (NSCR): using H2, HC, CO (see three-way catalyst)

Selective (SCR): requires metering of reductant into the exhaust

urea (in water) NH2-CO-NH2 decomposes into CO2 + NH3

“standard” SCR reaction: 4 NH3 + 4 NO + O2 -> 4 N2 + 6 H2O

“fast” reaction: 2 NO + 2 NO2 + 4 NH3 -> 4 N2 + 6 H2O

“slower” reactions: NO + NH3 -> N2 + O2 + H2O


Unwanted products: excess NH3, formation of N2O at lower temp.

• P. Forzatti, L. Lietti, E. Tronconi, Encyclopedia of catalysis, in: I.T.Horvath (Ed.), Nitrogen Oxides Removal – E (Industrial), J. Wiley,New York, 2002.

• A. Kato, S. Matsuda, T. Kamo, F. Nakajima, H. Kuroda, T. Narita, J. Phys.Chem. 85 (1981) 4099.

• Grossale, A., Nova, I., Tronconi, E., Chatterjee, D., & Weibel, M. (2008). The chemistry of the NO/NO 2–NH 3 “fast” SCR reaction over Fe-ZSM5 investigated by

transient reaction analysis. Journal of Catalysis, 256(2), 312-322.

• Nova, I., Ciardelli, C., Tronconi, E., Chatterjee, D., & Bandl-Konrad, B. (2006). NH 3–NO/NO 2 chemistry over V-based catalysts and its role in the mechanism of

the fast SCR reaction. Catalysis Today, 114(1), 3-12.

• Koebel, M., Madia, G., & Elsener, M. (2002). Selective catalytic reduction of NO and NO 2 at low temperatures. Catalysis Today, 73(3), 239-247.

https://www.researchgate.net/profile/Stefan_Mueller14/publication/235346314_Pulsed_Laser_Deposition_of_Electrochemically_Active_Perovskite_Films/links/

0f31753528a127ba75000000.pdf#page=61


Diesel particle filter



A. Liati, P. Dimopoulos Eggenschwiler / Combustion and Flame 157 (2010) 1658–1670



A. Liati, P. Dimopoulos Eggenschwiler / Combustion and Flame 157(2010) 1658–1670



A. Liati, P. Dimopoulos Eggenschwiler / Combustion and

Flame 157 (2010) 1658–1670


Lean NOx trap (LNT) / NOx storage and reduction (NSRC)

MAE, Emissions 56

Alternating lean (1-2 minutes) and rich (several seconds) phases

Lean phase:

Storage of NOx (i.e., BaCO3 -> Ba(NO3)2)

Rich phase:

Release of stored NOx & reduction as in three-way catalyst

Downsides and side effects:


Additional fuel consumption for rich phase

Release of NH3 and N2O


Selective and non-selective NOx reduction

MAE, Emissions 57

Non-selective (NSCR): using H2, HC, CO (see three-way catalyst)

Selective (SCR): requires metering of reductant into the exhaust

urea (in water) NH2-CO-NH2 decomposes (via HCNO) into CO2 + NH3

“standard” SCR reaction: 4 NH3 + 4 NO + O2 -> 4 N2 + 6 H2O

“fast” reaction: 2 NO + 2 NO2 + 4 NH3 -> 4 N2 + 6 H2O

“slower” reactions: NO + NH3 -> N2 + O2 + H2O


Unwanted products: excess NH3, formation of N2O at lower temp.

• P. Forzatti, L. Lietti, E. Tronconi, Encyclopedia of catalysis, in: I.T.Horvath (Ed.), Nitrogen Oxides Removal – E (Industrial), J. Wiley,New York, 2002.

• A. Kato, S. Matsuda, T. Kamo, F. Nakajima, H. Kuroda, T. Narita, J. Phys.Chem. 85 (1981) 4099.

• Grossale, A., Nova, I., Tronconi, E., Chatterjee, D., & Weibel, M. (2008). The chemistry of the NO/NO 2–NH 3 “fast” SCR reaction over Fe-ZSM5 investigated by transient reaction analysis. Journal of Catalysis, 256(2), 312-322.

• Nova, I., Ciardelli, C., Tronconi, E., Chatterjee, D., & Bandl-Konrad, B. (2006). NH 3–NO/NO 2 chemistry over V-based catalysts and its role in the mechanism of the fast SCR reaction. Catalysis Today, 114(1), 3-12.

• Koebel, M., Madia, G., & Elsener, M. (2002). Selective catalytic reduction of NO and NO 2 at low temperatures. Catalysis Today, 73(3), 239-247.https://www.researchgate.net/profile/Stefan_Mueller14/publication/235346314_Pulsed_Laser_Deposition_of_Electrochemically_Active_Perovskite_Films/links/0f31753528a127ba75000000.pdf#page=61


Real-world emissions could be higher than during „standardized tests“

(i.e., type approval)

• Optimization for type-approval conditions– No EGR at full load

– Catalyst sized for low flow and too small for high loads

• Technology limits - low SCR temperature – cold start, creep

• Malfunction & deterioration• „No one is watching“

– Switching off EGR, LNT fuel / SCR urea injection

– „Cycle beating“ strategy

– DPF removal, SCR deactivation, etc.


ADAC tests:EU diesel cars produce more NOx during WLTC

than during NEDC


Run NOx HC CO CO2 [kg] PM

1 65.31 94.30 11.32 5.92 0.256

2 100.05 92.49 11.84 6.44 0.305

3 65.29 91.88 18.52 6.15 0.296

4 95.31 93.74 16.50 6.35 0.314

Grams per cycle

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

1 61 121 181 241 301 361 421 481 541 601 661 721 781

gra

ms

pe

r s

ec

on

d

WVU Run 1

WVU Run 2

WVU Run 3

WVU Run 4

NOx

„DieselGate“: If the engine is not running under „test conditions”, NOx emissions are considerably higher (while

we save a small amount of fuel)

USA, heavy-duty truck, 16 years ago


http://www.nanoparticles.ch/archive/2017_Kuenzli_PR.pdf

„Excess” emissions due to “dual mapping” (and similar) have severe public health consequences …

Künzli ETH Nanoparticles 2017 / Anenberg et al., Nature 2017


Exclusion of diesel cars considered in several EU cities …

https://www.reuters.com/article/us-germany-emissions/german-court-backs-bid-to-ban-diesel-cars-in-stuttgart-idUSKBN1AD10Y


Diesel car NOx limit: 180 mg/km Euro 5, 80 mg/km Euro 6

Average emissions - Braunschweig cycle: 195 mg/km NOx.At 37 liters / 100 km, 220 g/kWh: 162 mg/kWh (Euro 6: 460 mg/kWh)

Diesel car real driving NOx: Euro 3-5: 1000 mg/km

One Euro 5 car = 1000 mg/km = 5 buses !!! But 5 buses can transport 100x more people.

SOR CN12 Euro 6 SOR CN12 Euro 6 diesel bus diesel bus –– HradHradččany military airportany military airport


https://www.epa.gov/sites/production/files/2016-12/documents/nox-memorandum-nox-petition-response-2016-12-20.pdf

U.S. Proposed limit: 0.02 g/bhpU.S. Proposed limit: 0.02 g/bhp--h by 2022h by 2022--20242024expected onexpected on--road emissions trucksroad emissions trucks--buses: 20buses: 20--40 mg/km40 mg/km

Current limit (2010): 0.20 Current limit (2010): 0.20 g/bhpg/bhp--hh, ~ 100, ~ 100--400 mg/km trucks & buses400 mg/km trucks & busesAverage EU diesel car: ~ 1000 mg/km Euro 3,4,5 / ~ 500 mg/km EurAverage EU diesel car: ~ 1000 mg/km Euro 3,4,5 / ~ 500 mg/km Euro 6o 6

EU diesel car limits: 180 mg/km Euro 5, 80 mg/km Euro 6EU diesel car limits: 180 mg/km Euro 5, 80 mg/km Euro 6


https://www.arb.ca.gov/msprog/tech/techreport/diesel_tech_report.pdf

U.S. Proposed limit: 0.02 g/bhpU.S. Proposed limit: 0.02 g/bhp--h by 2022h by 2022--20242024expected onexpected on--road emissions trucksroad emissions trucks--buses: 20buses: 20--40 mg/km40 mg/km

Current limit (2010): 0.20 Current limit (2010): 0.20 g/bhpg/bhp--hh, ~ 100, ~ 100--400 mg/km trucks & buses400 mg/km trucks & busesAverage EU diesel car: ~ 1000 mg/km Euro 3,4,5 / ~ 500 mg/km EurAverage EU diesel car: ~ 1000 mg/km Euro 3,4,5 / ~ 500 mg/km Euro 6o 6

EU diesel car limits: 180 mg/km Euro 5, 80 mg/km Euro 6EU diesel car limits: 180 mg/km Euro 5, 80 mg/km Euro 6


https://www.arb.ca.gov/msprog/tech/techreport/diesel_tech_report.pdf

U.S. Proposed limit: U.S. Proposed limit: 0.02 g/bhp0.02 g/bhp--h by 2022h by 2022--20242024((expected onexpected on--road emissions road emissions truckstrucks--buses: 20buses: 20--40 mg/km)40 mg/km)


European diesel cars vs. heavy vehiclesProposed limit:0.02 g-bhp/h

~ 30 mg/km NOx

US EPA 2010 heavy vehicle engine limit:0.2 g-bhp/h ~ 300 mg/km NOx


Budoucnost naftových motorů v městských aglomeracích závisí na ošetření výfukových emisí.Neohlídáme-li si emise (za skutečného provozu),

budou motory z měst vykázány.(Viz Stuttgart, Paříž, Londýn, a další)




0.0

0.5

1.0

1.5

2.0

2.5

0 5000 10000 15000 20000 25000 30000

test mileage

HC

[g/mile]1 2 3 17 18 20

0.0

0.5

1.0

1.5

2.0

2.5

0 5000 10000 15000 20000 25000 30000

test mileage

HC

[g/mile]1 2 3 17 18 20

Role of on-board, real-world emissions measurement

ResearchEngineeringType ApprovalHigh quality, high cost,Small number of vehicles

Inspection & maintenanceScreeningHigh number of vehiclesLow costLow precision

Measurement of individual vehicles during real-world oeprationLow to intermediate number of vehiclesWide variety of operating conditions

With PEMS, it is always necessary to match the instrumentation and test designs to what we want to find out.(Low-cost high-throughput vs. detailed high-accuracy measurement)

LABORATORY

ON-BOARD INSTRUMENTATION

OR CHASE VEHICLE

REMOTE SENSINGI/M PROGRAMS

EM

ISSIO

NS

HOURS / KM DRIVEN


Emissions:

Measurement techniques


Engine dynamometers – laboratory testing of

on-road heavy-duty & non-road engines


Chassis dynamometers – laboratory testing of

(primarily) light-duty on-road vehicles


• Exhaust contains water vapor and organic gases

• When cooled, water and organics condense, and additional particulate matter forms by condensation

• Raw exhaust approach:

– hot sampling train

• Diluted exhaust approach:

– avoid condensation by diluting below dewpoint

To dilute or not to dilute?


• Raw exhaust approach:

– Flow measured and synchronized with

concentrations

– Technically challenging but compact installation

• CVS / diluted exhaust approach:

– Flow constant and does not need to be

synchronized

– Technically proven but bulky installation

Mass emissions rate = concentration x flow


In some cases full-flow dilution tunnels are not practicaland neither is laboratory/dynamometer testing


Full flow dilution tunnel withconstant volume sampler (CVS)


Full flow dilution tunnel withconstant volume sampler (CVS)

Source: Horibahttp://www.horiba.com/automotive-test-systems/products/emission-measurement-systems/dilution-sampling-systems/details/cvs-one-constant-volume-sampler-19609/


Emissions:

Equations


Emissions - Equations

MAE, Emissions 79

Ideal combustion:


Real combustion:







Emissions - Equations

MAE, Emissions 80

Exhaust gas composition

N2 most dominant component in exhaust gas - when air used as oxidant

O2 when Air excess ratio λ> 1

•Complete oxidation products CO2, H2O

•Incomplete oxidation products CO, H2, HC

•Oxidation of atmospheric oxygen Oxides of nitrogen

NOx = nitric oxide NO + nitrogen dioxide NO2

•Decomposition of liquid fuel - soot


Emissions - Definitions

MAE, Emissions 81

Combustion reaction fuel + oxidizer -> products

c,h,o ___ constitution

coefficients of carbon,

hydrogen and oxygen in

a fuel

λ ___ air

excess ratioAi ___ chemical formula

of component i

ni ___ number of moles of

component i

Molar fraction of component i - output value of gas analyzer (% or ppm)

Σn total amount of moles formed by

combustion of one mole of fuel

Mass concentration – (g/m3) density at normal conditions


Emissions - calculations

MAE, Emissions 82

Mass balance

carbon

hydrogen

oxygen

nitrogen


Emissions - Definitions

MAE, Emissions 83

Theoretical air-to-fuel ratio

Mµ,02(N2) molecular weight of oxygen, nitrogen

Mµ molecular weight of fuel


• carbon balance

• volumetric flow of exhaust

• absolute and specific emission

Emissions – mass balance

MAE, Emissions 84

Vµ ___molar volume, Vµ = 22.41 dm3.mol-1, m3.kmol-1

Mf___Fuel consumption (kg.h-1)

ρj ___density of component j

cj___molar fraction of component

Pe___effective brake power


Emissions:

Measurement of basic gaseous pollutants


Emissions – Principles of measurement

Type approval / laboratory measurements:

• CO, CO2 – Non dispersive infra red analyzer (NDIR)

– Low and high ranges for CO

• THC – Flame ionization detector (FID)

• NO/NOX – Chemiluminiscence detector (CLD)

• non dispersive ultra violet detector (NDUV)

• O2 – Paramagnetic detector (PMD)

• PM – gravimetric measurement

• PN – volatile particle removal & condensation counter

• NH3, N2O – tunable diode laser, FTIR

MAE, Emissions 86


Emissions – Principles of measurement

Service / repair / inspection & maintenance programs:

• CO, CO2, HC – Non dispersive infra red analyzer (NDIR)

• NO – electrochemical cells

• PM – smoke opacity (SAE J -1667)

MAE, Emissions 87


CO, CO2, HC – Non dispersive infra red analyzer (NDIR)

MAE, Emissions 88

rotating chopper

disc

Measuring cell

Reference cell

Opto-pneumatic

gas comparator IR

source

Sample in Sample out

• Cross sensitivity elimination

– filtering

– postprocessing

• Measuring range typically only 1:10 (given by the cell length)– multiple sets of analyzers necessary (for low range, high range)

Absorption spectrum

rotating chopper disc

Gas layer

ρ ___gas densityL ___absorption lengthε, ___absorption coefficient

Lambert-Beer’s law

Fil

ter

cell


Non dispersive infra red analyzer (NDIR)

NO

NO2CH4

H2O

CO2

CO

NH3

DifferentHC

H2OCO2

http://www.esrl.noaa.gov/gmd/ccgg/faq_cat-3.html


HC - Flame Ionization Detector (FID)

MAE, Emissions AMA i60 — User’s Guide

Burner outlet

TFlame

SignalTHC

FID Fuel

Burner Air

Control Air

Calibration gas CH4 or C3H8

Sample gas

C … Capillary

F … Filter

N … Orifice/choking valve

P … Pressure monitoring

R … Control unit

Detector

Pump

Bypass outlet

Suction Force

Sample capillary

Heated MAEsuringchamber

typicallyResponse factor

Source: AVL AMA i60 — User’s Guide

Organic carbon atoms can be ionized in a hydrogen

flame.

Ion current ~ proportional

to the number of carbon

atoms.

Relative measurement

THCFID (C1 or C3)


NOX – Chemiluminiscence detector (CLD)

MAE, Emissions 91

Ozonator

Sample out

Gas Sample

Pump

Pressure control

Rotameter

Bypass

Photomultiplier

Reaction chamber

Reduction reactor

radiation energy at a certain wavelength

Filter

• No cross sensitivity

• Extremely large range (units to thousands of ppm)

• Oxygen necessary

• High voltage in ozonator

• The most expensive analyzer type


O2 – Paramagnetic detector (PMD)

• Thermomagnetic

• Magnetopneumatic

• Magnetomechanical

MAE, Emissions 92

1 .....Permanent magnet

2 .....Platinum wire3 .....Mirror

4 .....Ball

5 .....Wire loop

6 .....Light source7 .....Photoelectric cell

8 .....Electronic evaluation

equipment/Amplifier9 .....To measuring amplifier


Instrument transient response

https://vscht.cz/ufmt/cs/pomucky/vyslouzf/docs/dynamicke_vlast_chvs.pdf

td – transport delay, tk – time constant


Transient response

• Transport delay

• Chamber scavenging

• t90 ~ flow/volume

MAE, Emissions 94


Calibration

• Calibration gas

• Verification of calibration curve

– Zero gas, span gas

Offset + slope

• Span gas = component + nitrogen

• Linearization correction

• NDIR – calibration chamber

• FID – component + synthetic air

– C1, C3

MAE, Emissions 95


Calibration gases

http://paisleyandjohnstone.tripod.com/


Accessory

• Filtering

• Sample pumps

• Pressure and flow control

• Handling of water content

– Wet vs dry sample

– Heated sample line vs sample

MAE, Emissions 97


Emissions:

Particulate matter

&

Advanced measurements


Particle mass measurement – gravimetry


Particle number measurement - PMP

http://www.horiba.com/automotive-test-systems/products/emission-measurement-systems/analytical-systems/particulates/details/mexa-2000spcs-series-4331/


Particle number measurement - PMP

http://www.engr.ucr.edu/~heejung/publications/2012-PMP.pdf


Smoke opacity

Opacity = 1 – E/Eo

E – intensity of light (with particles)

Eo – intensity of light with particles absent (zero reference)

Opacity = 1 – exp(-kL)

L = optical length [m]

k = absorption coefficient [m-1]

http://www.arb.ca.gov/enf/hdvip/saej1667.pdf

http://www.wagerusa.com/media/files/6500operationsmanual.pdf


PortableFTIR

LaboratoryFTIR

Rotating discMicrodiluter

& EEPS

Full-flowDilutiontunnel

High-volumesamplers

PMP-compliantparticle counter

Dilution tunnel instrumentation


DetectorDetector

IR SourceIR Source

Fixed mirrorFixed mirror

x 0 -xx 0 -x

BeamsplitterBeamsplitter

Laser diodeLaser diodeHeHe--NeNe laserlaser

SampleSample

Moving mirrorMoving mirror

FTIR (Fourier Transform Infra Red) SpectrometerFTIR (Fourier Transform Infra Red) Spectrometer-- measures large portion of infrared spectrameasures large portion of infrared spectra

-- quantification of compounds absorbing in IR through quantification of compounds absorbing in IR through deconvolutiondeconvolution of spectra of spectra

NO

NO2CH4

H2O

CO2

CO

NH3

DifferentHC

H2OCO2

Diagram: Nicolet

-- greenhouse gases CO2, CH4, N2Ogreenhouse gases CO2, CH4, N2O-- reactive nitrogen compounds NO, NO2, reactive nitrogen compounds NO, NO2, NH3, HCN, HCNONH3, HCN, HCNO-- various heterogeneous molecules various heterogeneous molecules present in concentrations that can be present in concentrations that can be detected and discerned from other detected and discerned from other compoundscompounds


OnOn--board FTIR tests, Euro 6 truck, 12 tons gross weightboard FTIR tests, Euro 6 truck, 12 tons gross weight““PortablePortable”” FTIR: ~FTIR: ~35 kg, ~300 W, 0.5 cm35 kg, ~300 W, 0.5 cm--11, 5 m cell, 130 C, t, 5 m cell, 130 C, t1010--9090 ~3s~3s

““mobilemobile”” FTIR: ~FTIR: ~90 kg, ~600 W, 0.5 cm90 kg, ~600 W, 0.5 cm--11, 6 m cell, 130 C, t, 6 m cell, 130 C, t1010--9090 ~3s~3s

BatteriesChargerInverter

Particlecounter

3 tons of weights(total payload 3,5 t = 58%)

12 tons gross weight9.5 tons actual weight

Portable FTIRproject MEDETOX

TU Liberec

Mobile FTIR(laboratory grade Nicolet Antaris IGS)

Czech Techical Univ Prague


Particle classification by size: Impactor

http://www.dekati.com/products/Fine%20Particle%20Measurement/DGI


Particle classification by size: Electric mobility


Real driving emissions


Student projects: Unregulated emissions - E85, n-butanol, isobutanol in unmodified gasoline engines in Škoda cars

On-board FTIR6 m cell

0.5 cm-1 optical resolution~ 30 kg, ~ 300-400 W7-8 hours on ~60 kg of

batteries

SAE 2015-24-2513SAE 2015-24-2488SAE 2013-24-0102

Nitrogen compounds speciationNO, NO2, NH3

Greenhouse gasesN2O, CH4, CO2

Formaldehyde, acetaldehyde, other compounds or functional groups


Emissions:

Legislation

Documents

Internal combustion engine emissions - Katedra … · Experimental methods class –engines, vehicles, emissions testing lecture Michal Vojtisek, [email protected], tel, +420