Measurement of late-model diesel automobile real driving ... · Measurement of late-model diesel automobile real driving emissions of reactive nitrogen compounds with on-board FTIR

FTIR measurement of real driving emissions of reactive nitrogen – Vojtisek et al. – TAP May 2016 1

Measurement of late-model diesel automobile real driving emissions of reactive nitrogen compounds with

on-board FTIR analyzer

MichalMichal VojtisekVojtisek--LomLom, V, Víít Bert BerááneknekInstitute for Automobile, Combustion Engine and Railway Engineering,

Czech Technical University in PragueCzech Technical University in Prague

Martin Martin PechoutPechout, , LuboLubošš DittrichDittrichDepartment of Vehicles and Engines, Faculty of Mechanical Engineering,

Technical University of Technical University of LiberecLiberec

Contact: [email protected], tel. (+420) 774 262 854

Transport and Air Pollution Conference, Lyon, May 23-26, 2016


Particulate matter and ground -level ozone are responsible for over 400 thousands premature

deaths in the EU(traffic accidents for „only“ 39 thousands)


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


Project BIOTOX – Mechanisms of Toxicity of Particles from BiofuelsPM measurement and sampling using high-volume samplers

Gasoline MPI and direct injection, diesel,Traditional and alternative fuels (ethanol,

butanol, biodiesel, NExBTL, blends)


„Celý den jezdíauty sem a tam, aby ukázali, že

ježdění autem je špatné pro

životníprostředí.“

(Steve Taylor, New York)

Cars, buses, trucks, tractors, loaders, mowers, small airplanes, mopeds, ferries, locomotives, construction machinery

Real driving emissions measurementReal driving emissions measurementPortable onPortable on--board monitoring systems (PEMS)board monitoring systems (PEMS)


Evaluation of real driving Evaluation of real driving emissions (RDE) withemissions (RDE) with

portable onportable on--board emissions board emissions monitoring systems (PEMS)monitoring systems (PEMS)

TypeType--approval grade:approval grade:AVL AVL –– gaseous pollutants gaseous pollutants

NanoMetNanoMet 3 3 –– particle number (PN)particle number (PN)

InIn--house built researchhouse built research--gradegrade::““MiniMini--PEMSPEMS”” (13 kg, 60 W)(13 kg, 60 W)OnOn--board portable FTIR board portable FTIR (non(non--regulated compounds)regulated compounds)

OnOn--board particle counters and board particle counters and particle classifier (EEPS)particle classifier (EEPS)

ServicesServices: PEMS & laboratory testing: PEMS & laboratory testingTest design and facilitationTest design and facilitation

Data analysis and interpretationData analysis and interpretation

StaffStaff: : MichalMichal VojtisekVojtisek designed the designed the first commercially available PEMSfirst commercially available PEMS

20 years PEMS & RDE in USA & EU20 years PEMS & RDE in USA & EU


One of the first PEMSOne of the first PEMSPittsburgh, USA, 1996Pittsburgh, USA, 1996--19991999

Pennsylvania State UniversityPennsylvania State UniversityUSA, 2001USA, 2001--20032003

Real driving emissions (RDE) measurement usingReal driving emissions (RDE) measurement usingPortable Emissions Monitoring Systems (PEMS)Portable Emissions Monitoring Systems (PEMS)

Work by the authorWork by the author

First commercially First commercially available PEMS available PEMS ––

OEMOEM--21002100Manufactured Manufactured 19991999--20022002


Commercially sold PEMSCommercially sold PEMSMontana systemMontana system

20022002--20052005 PEMS FTIRPEMS FTIR20042004--20062006

Real driving emissions (RDE) measurement usingReal driving emissions (RDE) measurement usingPortable Emissions Monitoring Systems (PEMS)Portable Emissions Monitoring Systems (PEMS)

Work by the authorWork by the author


Portable on-board exhaust emissions monitoring system (current version)

HC, CO, NO, NO2, PM mass, PM length

1

10

100

1000

1.E+04 1.E+05 1.E+06 1.E+07

EEPS total number concentration > 23 nm [#/cm3]

ioni

zatio

n ch

am

ber

leng

th c

once

ntra

tion

[mm

/cm

3]

Rapeseed oil no DPF

Rapeseed oil with DPF

Diesel fuel no DPF

Diesel fuel with DPF

Length vs.PN>23 nmwith volatiles

lengthlength mean

mobility diameter

heated ionization“fire detector”undiluted raw

exhaust(multiplied by intake air flow

for comparison measurements)

~ 0.1 mg/m3 sensitivity

cheap (100 EUR)“poor man’s PEMS”

concept

0

10

20

30

40

50

60

14:13:00 14:15:00 14:17:00 14:19:00 14:21:00

NO

x [m

g/s]

, PM

*10

[mg/

s],

CO

2 [g

/s],

spee

d [k

m/h

]

CO2 NOx PM*10 rpm km/h

Installs on motorcycles to locomotives

This example �from a Euro 4

diesel car

Online real-world measurementsIncl. PM on SI

SAE 2013-24-0102 SAE 2013-24-0168


Engine

10-12 lpmraw exhaust

Condensateand large particleremoval

Samplecool & reheat

Filtered dilution air

Nephelometer(laser scattering)

Charge meter

F-FC-P

F-FC-P

F-FC-P

F-FC-P

NDIR-HC,CO,CO2

NDIR-HC,CO,CO2

chem.cell NOF-FC-P

chem.cell NO

outflow

Filter, flow control, pump

CAT

Before or afterDOC, DPF, …

On-board monitoring systemResponse approximately proportional to PM mass

concentrations for a given engine

Modified ionization smoke alarm (a 100 EUR system) - response

proportional to total particle length(close to lung deposited surface area?)


On-board system versatility: Motorcycle to locomotive

Raw exhaust sampling point

(no dilution)

Engine speed measured with

optical tachometer

Intake air manifold absolute pressure

5 Hz GPS receiver Speed,

position, altitude

Battery

2009 ColiberFartt

scooter0.049 liter carbureted

engine

Special adapter fabricated and inserted before muffler (outside air penetrates well into

tailpipe)

Truck

Locomotive163 liter diesel


Transfer line

Transferline

PMsampling

Batteries

Flow meter

Mini-PEMSHC,CO,CO2,NO,NO2,PM

MiniPEMSRaw ordiluted

Full-flow dilutiontunnel

Portable on-board exhaustemissions monitoring systemHC, CO, CO2, NO, NO2,

PM mass, PM lengthCalculated exhaust flow

“Motorcycle to locomotive”Full-flow dilution tunnel with particle sampling

for small non-road engines


Sampling lineSampling line

SuperinsulatedSuperinsulated

Heated to 150 CHeated to 150 C

Gases:Gases:

FTIR spectrometer FTIR spectrometer

650650--4000 cm4000 cm--11

6 m optical length6 m optical length

0.5 cm0.5 cm--11 resolutionresolution

Methane, formaldehyde,Methane, formaldehyde,

CO, CO2, NO, NO2, ...CO, CO2, NO, NO2, ...

Dilution for PM:Dilution for PM:

Rotating disc microdiluterRotating disc microdiluter

MDMD--19, Matter Engineering 19, Matter Engineering

150 C dilution head150 C dilution head

150:1 dilution ratio150:1 dilution ratio

PM sizes and count:PM sizes and count:

Electric mobility classifier Electric mobility classifier

and spectrometerand spectrometer

EEPS model 3090, TSIEEPS model 3090, TSI

1 Hz measurement1 Hz measurement

55--560 nm560 nm

MEDETOXMEDETOXprototypeprototype


Euro 6 diesel truck (DOC, DPF, SCR)Euro 6 diesel truck (DOC, DPF, SCR)Two FTIRTwo FTIR--PEMS PEMS & & ““ordinaryordinary”” PEMS & particle counterPEMS & particle counter

BatteriesChargerInverter

FTIRMEDETOXTU Liberec

FTIRCzech TechUniv Prague

Particlecounter

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

12 tons gross weight9.5 tons actual weight


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

On-board FTIR~ 30 kg

~ 300-400 W3 hours on

26 kg of batteries


ADAC test results:

Diesel cars

WLTP cycle

NOx


Why are NOx higher during real driving

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

• Optimization for cycle / off-cycle emissions

– No EGR at full load

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

• „No one is watching“

– Switching off EGR, LNT fuel / SCR urea injection

– „Cycle beating“ strategy


0

5

10

15

20

25

30

35

40

45

50

16:00:00 16:15:00 16:30:00 16:45:00

PM

in e

xhau

st [m

g/m

3]ex

haus

t tem

p [C

] / 1

0

-60

-45

-30

-15

0

15

30

45

60

75

90

spee

d [k

m/h

]

EGT/10[C]

PM [mg/m3]

speed [km/h]

Heavy vehicle creep problem

* Deterioration of combustion at idle* Low exhaust gas temperatures decrease efficiency of catalytic devices (DOC, SCR)* Particulate matter stored in exhaust system to be released later

Increase in PM emissions“getting out of creep”

Practical efficiency limit of DOC, SCR


Congestion effects: DAF 1505 truck, 2006, Euro 5 Paccar engine, 540 thousands km, with loaded trailer (39 tons total weight)


We took a DAF truck with semi-trailer, 39 tons, EURO 5 but no DPF, and circulated the Prague perimeter road waiting for congestion to happen

“Urban creep”:combustion worsens, DOC cools down, SCR cools down, EGR not feasible

Result: NOx and PM up to one order of magnitude higher

0.01

0.1

1

10

100

1000

10000

9:00:00 10:00:00 11:00:00 12:00:00 13:00:00 14:00:00 15:00:00 16:00:00 17:00:00 18:00:00

fuel

-spe

cific

NO

x an

d P

M

emis

sion

s [g

/kg]

-200

-150

-100

-50

0

50

100

road

spe

ed [k

m/h

]

FS-Nox

FS-PM

km/h

30 per. Mov. Avg. (km/h)

120 per. Mov. Avg. (FS-PM)

120 per. Mov. Avg. (FS-Nox)

Euro 5 equivalents at 250 g/kWh: 2.0 g/kWh ~ 8 g NOx/kg fuel / 0.02 g/kWh ~ 0.08 g PM/kg fuel

The horror of transit truck traffic


Challenges of EU automobile diesel enginesEuro 4 Skoda Fabia – chassis dynamometer runs

NEDC vs. full-power loaded accelerations

NOx reduced by EGR

NOx: Use of EGR competes with the

desire for additional torque

?

Maintaining adequate excess air competes

with desire for additional torque

NOx

PM

Long idle / low load: DOC cooldown, combustion deterioration, high fraction

of OC in PM

Problem compounded by downsizing &

turbocharging: Relatively low torque at idle.

Problem compounded by cold DOC during accelerations after long idle


Euro 4 Skoda Octavia – real-world city driving tests

Measurement by the author.

0

10

20

30

40

50

60

14:13:00 14:15:00 14:17:00 14:19:00 14:21:00

NO

x [m

g/s]

, PM

*10

[mg/

s],

CO

2 [g

/s],

spee

d [k

m/h

]CO2 NOx PM*10 rpm km/h


Euro 4 Škoda Octavia – high-speed freeway tests

PM

-4

-3

-2

-1

0

1

2

3

4

0 20 40 60 80 100 120 140 160 180

road speed [km/h]

acce

lera

tion

[m/s

2 ]

Real-world freeway

ECE 2 (dyno)

NO

-4

-3

-2

-1

0

1

2

3

4

0 20 40 60 80 100 120 140 160 180

road speed [km/h]

acce

lera

tion

[m/s

2 ]

Real-world freeway

ECE 1

ECE 2

Aggressive, high-speed driving on a freeway, not atypical for Czech roadsResults contrasted with ECE cycle test on a chassis dynamometer


Cumulative NOx emissions over cold vs. hot start NEDCEuro 5, VW Passat

0

0.5

1

1.5

2

2.5

3

3.5

0 200 400 600 800 1000 1200 1400

g N

Ox

(NO

+NO

2)

-20

0

20

40

60

80

100

120

1600 1800 2000 2200 2400 2600 2800 3000

km/h

NEDC-cold-NOxNEDC-hot-NOxroad speed

Euro 5 limit 180 mg/km


This work: This work: ŠŠkoda Octavia Euro 5 diesel, LNTkoda Octavia Euro 5 diesel, LNTGoal: Examination of RDE emissions of nitrogen Goal: Examination of RDE emissions of nitrogen

species: NO, NO2, NH3, N2Ospecies: NO, NO2, NH3, N2OTU Liberec to EC Joint Research Center (Ispra, Italy)TU Liberec to EC Joint Research Center (Ispra, Italy)

About 8 hours of instrument run timeAbout 8 hours of instrument run time ((6:45 sampling time6:45 sampling time))(limited by battery and liquid nitrogen capacity)(limited by battery and liquid nitrogen capacity)

Germany (high speed)Germany (high speed) & & Switzerland (hills and high altitude)Switzerland (hills and high altitude)Germany:

431.75 km, 4:526.4 mg/km N2O687 mg/km NOx158 g/km CO2

Switzerland: 84.66 km, 1:53217 mg/km NOx140 g/km CO2


Euro 5 diesel car, LNT

LNT regeneration: spikes in CO2 (> 14%) and COSpikes in CH4, N2O (otherwise negligible)No regeneration = saved fuel, high NOx

0

100

200

300

400

500

600

700

800

13:40 13:45 13:50 13:55 14:00 14:05 14:10 14:15 14:20 14:25 1 4:30 14:35 14:40

NO

[ppm

], C

H4

[ppm

]

0

15

30

45

60

75

90

105

120

CO

2 [%

], N

2O [p

pm]

CH4 [ppm]NOx [ppm]N2O [ppm]CO2 [%]

LNT regenerations

-75-60-45-30-15

01530456075

spee

d [k

m/h

]

-2-1012345678

acce

lera

tion

[m/s

2]

no LNT regeneration = higher NOx


0

500

1000

1500

2000

18:20 18:35 18:50 19:05 19:20 19:35

NO, NO2, CH4

[ppm]

-600000-500000-400000-300000-200000-1000000100000200000

CO2 [ppm]

NO (ppm)NO2 (ppm)CH4 (ppm)CO2 (ppm)

1

10

100

1000

10000

18:20 18:35 18:50 19:05 19:20 19:35

N2O, CH4

[ppm]-600000-500000-400000-300000-200000-1000000100000200000

CO2 [ppm]

CH4 (ppm)N2O (ppm)CO2 (ppm)

ŠŠkoda Octavia Euro 5 diesel, LNTkoda Octavia Euro 5 diesel, LNT


ŠŠkoda Octavia Euro 5 diesel, LNTkoda Octavia Euro 5 diesel, LNT

0

20

40

60

80

100

120

140

160

180

0 50 100 150 200 250 300 350 400 450 500elapsed

distance [km]

spee

d [k

m/h

] (1

00 m

avg

)

0

0.4

0.8

1.2

1.6

2

2.4

2.8

3.2

3.6

NO

x [g

/km

]

Speed [km/h]NOx [g/km]50 per. Mov. Avg. (NOx [g/km])

0

20

40

60

80

100

120

140

160

180

0 50 100 150 200 250 300 350 400 450 500elapsed

distance [km]

spee

d [k

m/h

] (1

km

avg

)

0

0.4

0.8

1.2

1.6

2

2.4

2.8

3.2

3.6

NO

x [g

/km

] (1

km a

vg)

Speed [km/h]NOx [g/km]10 per. Mov. Avg. (NOx [g/km])


0.001

0.01

0.1

1

10

100

0 100 200 300segment average CO2 [g/km]

segm

ent a

vera

ge N

Ox

[g/k

m]

0.0001

0.001

0.01

0.1

1

10

segm

ent a

vg m

g N

Ox

/ g C

O2

NOx [g/km]

Nox/CO2

0.001

0.01

0.1

1

10

100

0 50 100 150 200 250 300

segment average CO2 [g/km]se

gmen

t ave

rage

NO

x [g

/km

]

0.0001

0.001

0.01

0.1

1

10

segm

ent a

vg m

g N

Ox

/ g C

O2

NOx [g/km]

Nox/CO2

ŠŠkoda Octavia Euro 5 diesel, LNTkoda Octavia Euro 5 diesel, LNT> 500 km of data> 500 km of data

100 m resolution100 m resolution 1 km resolution1 km resolution

NOxNOx –– both absolute and per CO2 (per kg fuel) both absolute and per CO2 (per kg fuel) ––Exponentially increase with fuel consumption (g/km CO2)Exponentially increase with fuel consumption (g/km CO2)


0

50

100

150

200

250

300

350

80 100 120 140 160

segment average speed [km/h]

segm

ent C

O2

[g/k

m]

NOx [g/km]

0

50

100

150

200

250

300

350

80 100 120 140 160

segment average speed [km/h]se

gmen

t CO

2 [g

/km

]

NOx [g/km]

NOxNOx exponentially increase with road speedexponentially increase with road speed




0

50

100

150

200

250

300

350

80 100 120 140 160


segm

ent C

O2

[g/k

m]

Nox/CO2

0

50

100

150

200

250

300

350

80 100 120 140 160


gmen

t CO

2 [g

/km

]

Nox/CO2



NOxNOx per kg CO2 (per kg of fuel)per kg CO2 (per kg of fuel)exponentially increase with road speedexponentially increase with road speed


0.001

0.01

0.1

1

10

100

0 20 40 60 80 100 120 140 160


segm

ent a

vera

ge N

Ox

[g/k

m]

0.0001

0.001

0.01

0.1

1

10

segm

ent a

vg m

g N

Ox

/ g C

O2

NOx [g/km]

Nox/CO2

0.001

0.01

0.1

1

10

100

0 20 40 60 80 100 120 140 160


gmen

t ave

rage

NO

x [g

/km

]

0.0001

0.001

0.01

0.1

1

10

segm

ent a

vg m

g N

Ox

/ g C

O2

NOx [g/km]

Nox/CO2



NOxNOx –– both per km and per kg CO2 (or kg of fuel)both per km and per kg CO2 (or kg of fuel)exponentially increase with road speedexponentially increase with road speed



GermanyGermany SwitzerlandSwitzerland

NOxNOx appear to be well comparable with Euro 5 standards appear to be well comparable with Euro 5 standards throughout Switzerland (max. 120 km/h, avg. 0.217 g/km).throughout Switzerland (max. 120 km/h, avg. 0.217 g/km).On the autobahn in Germany, On the autobahn in Germany, NOxNOx were generally higher were generally higher (>0.18 g/km >70% of the distance, avg. 0.69 g/km).(>0.18 g/km >70% of the distance, avg. 0.69 g/km).

Relative frequency of speed and NO x

00.10.20.30.40.50.60.70.80.9

1

0 20 40 60 80 100 120 140 160 180Speed [km/h]

Rel

ativ

e fre

quen

cy [-

]

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 0.5 1 1.5 2 2.5 3 3.5NOx production [g/km]

Relative frequency of speed and NO x

00.10.20.30.40.5

0.60.70.80.9

1

0 20 40 60 80 100 120 140Speed [km/h]

Rel

ativ

e fre

quen

cy [-

]

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 0.1 0.2 0.3 0.4 0.5 0.6

NOx production [g/km]


SOR CN12 Euro 6 SOR CN12 Euro 6 diesel busdiesel busHradHradččany military airport any military airport Braunschweig driving cycleBraunschweig driving cycle

Goal: Evaluation of production Goal: Evaluation of production of N2O, NH3, NO2 by diesel of N2O, NH3, NO2 by diesel

and CNG busesand CNG buses


NO, NO2, N2O, NH3, ...., CO, CO2, PM

0

20

40

60

80

100

120

140

0 300 600 900 1200 1500 1800 2100

rych

lost

[km

/h

], p

ali

vo

[d

m3

/h

]

-50

-40

-30

-20

-10

0

10

20

N

O [

mg

/s],

N

O2

[m

g/

s]

palivo-dle-ECU [dm3/h] palivo-dle-CO2 [dm3/h] rychlost [km/h]

NO [mg/s] NO2 [mg/s]

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

0

20

40

60

80

100

120

140

14:14:00 14:19:00 14:24:00 14:29:00 14:34:00 14:39:00 14:44:00 14:49:00

sp

ee

d [

km

/h

], f

ue

l [d

m3

/h

]

-30

-20

-10

0

10

20

30

40

NO

, N

O2

[m

g/s]

fuel-from-ECU [dm3/h] fuel-from-CO2 [dm3/h]

actual speed [km/h] prescribed speed

NO [mg/s] NO2 [mg/s]


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

Average emissions - Braunschweig cycle: 195 mg/km NO x.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


Do we limit the diesel engine to heavyDo we limit the diesel engine to heavy--duty duty vehicles, just like in vehicles, just like in the the United States?United States?

Is car really the best way for highIs car really the best way for high--speed speed intercity travel?intercity travel?


Conclusions & ImplicationsConclusions & ImplicationsReal driving emissions of NO, NO2, NH3, N2O (+ more)Real driving emissions of NO, NO2, NH3, N2O (+ more)

measured with portable FTIRmeasured with portable FTIR> 500 km, 6 > 500 km, 6 ¾¾ hours on batteries and liquid nitrogenhours on batteries and liquid nitrogen

Measurement is possibleMeasurement is possibleInterpretation of spectra for additional compounds is also Interpretation of spectra for additional compounds is also

possible later after the measurementpossible later after the measurementDifficult to generalize based on one or several vehiclesDifficult to generalize based on one or several vehicles

Results suggest Results suggest NOxNOx elevated at higher (offelevated at higher (off--cycle) speedscycle) speeds,,and and „„compliantcompliant““ results throughout Switzerland (results throughout Switzerland (<= <= 120 km/h)120 km/h)

Germany: 431.75 km, 4:526.4 mg/km N2O, very low NH3687 mg/km NOx, 158 g/km CO2Switzerland: 84.66 km, 1:53

217 mg/km NOx, 140 g/km CO2


Czech Science Foundationproject BIOTOX (13-0148S):

Mechanisms of toxicity of particles from biofuels

European Social Fund, CZ.1.07/2.3.00/30.0034Support of Research Teams at Czech Technical University in Prague.

Thank you !

EU LIFE+ program, project MEDETOX - Innovative Methods of

Monitoring of Diesel Engine Exhaust Toxicity in Real Urban Traffic (LIFE10 ENV/CZ/651)

Warning: This engine may produce nanoparticles that are harmful when inhaled.

Documents

Measurement of late-model diesel automobile real driving ... · Measurement of late-model diesel automobile real driving emissions of reactive nitrogen compounds with on-board FTIR