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TNO report
TN02013R11891

www.tno.nl

Investigations and real world emission
performance of Euro 6 light-duty vehicles

T+

Date

5 December 2013

Author(s)

No. of copies

Number of pages
Number of
appendices
Sponsor
Project name
Project number

0100003108
53 (mcl. appendices)
2
Dutch Ministry of lnfrastructure and the Environment
lenM LD steekproef 2013-2015
057.02764

All rights reserved.
No part of this publication may be reproduced and/or published by print, photoprint,
microfilm or any other means without the previous written consent of TNO.
In case this report was drafted on instructions, the rights and obligations of contracting
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the relevant agreement concluded between the contracting partjes. Submitting the report for
inspection to parties who have a direct interest is permitted.
© 2013 TNO

Ei

TNO report 1 TNO 2013 Ri 18911 5 December 2013

2142

Samenvatting
Uit onderzoek uitgevoerd in opdracht van het Ministerie van infrastructuur en Milieu
blijkt dat de NOK-emissie van een aantal geteste Euro 6 dieselpersonenauto’s onder
praktijkomstandigheden hoger ligt dan op grond van de Euro 6 norm mocht worden
verwacht. De Euro 6 norm wordt in 2014 van kracht en beoogt een substantiële
verlaging van de schadelijk uitstoot van personenautos en bestelwagens.
Ondanks het aanscherpen van de NO)<-norm van Euro 5 (180 mg/km) naar Euro 6
(80 mg/km) ligt de praktijk NON-emissie van de geteste voertuigen op circa 500
mg/km, d.w.z. hetzelfde niveau als van Euro 4 en Euro 5 dieselpersonenauto’s.
In opdracht van het ministerie van Infrastructuur & Milieu heeft TNO onderzoek
gedaan naar het praktijkemissiegedrag van Euro 6 personenwagens die zijn
uitgerust met dieselmotor. Het onderzoek is een basis voor de emissiefactoren die
in 2014 worden vastgesteld. Ook heeft het ministerie aan TNO gevraagd adviezen
op te stellen voor maatregelen die resulteren in lage praktijkemissies en in lijn zijn
met de emissies in de typegoedkeuringstest.
Bij de uitgevoerde testen gaat het zowel om metingen in het laboratorium op de
rollenbank als om metingen met mobiele meetapparatuur (PEMS) op de weg. De
geteste voertuigen voldoen op basis van de NEDC typekeuringstest aan de Euro 6
NOK-norm van 80 mg/km. Echter onder praktijkomstandigheden ligt de NON-uitstoot
tot wel een factor 6 hoger. Eén getest voertuig presteerde wel goed en haalde
onder praktijkomstandigheden 35-95% van de NOx limietwaarde.
Leeswijzer:
Dit onderzoek is gebaseerd op diverse emissiemetingen aan Euro 6 diesel
personenwagens. De metingen zijn in 2010 en 2013 uitgevoerd, zowel in een
laboratorium als op de weg.
Vervolgens zijn de meetresultaten beoordeeld aan de hand van de toegepaste
nabehandelingstechnologie. Tevens zijn de emissiefactoren bepaald en vergeleken
met emissiefactoren van oudere voertuigen.
Ook zijn de resultaten van dit onderzoek vergeleken met resultaten van een aantal
andere Europese instituten.
Als laatste zijn op basis van deze resultaten aanbevelingen gedaan voor de
regulering van praktijkemissies in de toekomstige emissiewetgeving.
Reden tot zorg:
Ondanks een voortdurende aanscherping van de NOx emissienormen van Euro 1
1 van dieselpersonenauto’s op de snelweg
naar Euro 6, zijn de NO emissiefactoren
de laatste 10 jaar ongeveer gelijk gebleven (400 —600 mg!km). In stadsverkeer is
er wel sprake van reductie (van 1000 naar 200 mg/km) maar de NOx emissie ligt
nog altijd ver boven de limietwaarde van de typegoedkeuring (80 mg/km). Zie ook
Figuur 1.
In 2010 zijn enkele metingen uitgevoerd aan de eerste Euro 6
dieselpersonenauto’s. Deze eerder geteste voertuigen uit voorserie modellen’ (pre

Een emissiefactor is een op basis van meetdata berekend gemiddelde voor de vloot

TNO report 1 TNO 2013 RI 18911 5 December 2013

3142

Euro 6), die ook leverbaar zijn op de Amerikaanse markt, presteerden beter dan de
huidige Euro 6 productiemodellen.

• urban

motorway

—

Type Approval Limit value

1,20

1,00
0
—

0,80

0
z
0,60

Euro1

Figure 1:

Euro-2

Euro3

hi#
Euro-4

Euro-5

Euro-6

pre-Euro-6

NOx emissiefactoren voor stad en snelweg en limietwaarden bij typegoedkeuring van
dieselpersonenwagens

Tot op heden is in Nederland een gering aantal Euro 6 dieselauto’s verkocht. Het
betreft vooral duurdere voertuigen. Voor kleinere voertuigen wordt namelijk nog
geen Euro 6 technologie geleverd. Vanaf 1 september 2014 zullen echter alle
nieuwe typen personenwagens en kleine bedrijfswagens moeten voldoen aan Euro
6 emissienormen. Eén jaar later zullen alle voertuigen waarvoor een kenteken
wordt aangevraagd aan deze emissienorm moeten voldoen. Vermoedelijk zullen de
kleinere Euro 6 dieselvoertuigen, die op dit moment nog niet leverbaar zijn, met
goedkopere technologie worden uitgerust. Dit kan leiden tot andere (hogere!)
praktijkemissies en bijstelling van de emissiefactoren.
Uit de metingen blijkt dat Euro 5 en Euro 6 voertuigen met benzinemotor in de
praktijk wel lage NOx emissies hebben.
Toegepaste nabehandelingstechnologie is van grote invloed:
De NO praktijkemissies van Euro 6 dieselvoertuigen variëren zeer sterk.
Afhankelijk van de testcondities en het voertuig is de spreiding 10% tot 1000% van
de limietwaarde. Dit wordt hoofdzakelijk veroorzaakt door het type, de werking en
regelstrategie van de uitlaatgasnabehandelingstechnologie. Beschikbare
technologieën zijn EGR (uitlaatgasrecirculatie), SCR (selectieve katalytische
reductie) en LNT (Lean NOx Trap). Net als bij Euro 5 dieselvoertuigen wordt bij
Euro 6 voertuigen selectief gebruik gemaakt van deze systemen die zorg dragen
voor verlaging van NOx-emissies in de uitlaatgassen. De regelstrategie is zodanig
dat EGR en SCR systemen tijdens de rijomstandigheden die optreden bij de
typekeuringstest functioneel zijn, maar onder praktijkomstandigheden om
economische redenen (gedeeltelijk) worden uitgeschakeld.

TNO report 1 TNO 2013 Ri 18911 5 December 2013

4142

Bij de geteste voertuigen ging het om duurdere middenklasse of grotere auto’s die
met EGR en SCR dan wel met LNT waren uitgerust. Goedkopere Euro-6
dieselpersonenauto’s uit de compacte klasse of kleiner zijn nog niet of nauwelijks
op de markt. Het is waarschijnlijk dat de kleinere en goedkope alsook de
middelgrote dieselvoertuigen die in Nederland het hoofdaandeel in het
dieselsegment vormen, zullen worden uitgerust met de goedkoopste Euro 6
technologie. Fabrikanten passen dan alleen EGR toe om auto’s op de
typekeuringstest aan Euro-6 te laten voldoen. Beschikbare systemen als SCR en
LNT die onder praktijkomstandigheden een forse NOx-reductie kunnen leveren
zullen bij deze modellen naar verwachting niet worden toegepast. Net als Euro 5
voertuigen levert dit vooral een risico van hoge NO praktijkemissies op de snelweg.
Verwacht wordt dat de praktijk NO-emissies van deze kleinere Euro 6
dieselpersonenauto’s ook op het niveau van Euro 5 uit zullen gaan komen.
Resultaten emissiemetingen dieselvoertuigen TNO en TUG:
Alle Euro 6 dieselvoertuigen blijken in de typegoedkeuringstest aan de limietwaarde
van 80 mg/km te voldoen, maar de doorwerking daarvan in de praktijk blijkt beperkt.
Dit komt vooral tot uiting in meer praktijkgerichte metingen. Op de rollenbank is dit
de CADC-test en op de weg in testen in het stadsverkeer, op de buitenweg en op
de snelweg. Ook hier valt de NO praktijkemissie het meest op, die is gemiddeld
400-500 mg/km (5-6 keer limietwaarde). In de testen op de openbare weg (stad,
buitenweg, snelweg) zijn gemiddelde NO emissies van 550 800 mg/km gemeten,
dit is 7—10 keerde limietwaarde van de typegoedkeuringstest. Verder valt op dat
de spreiding onder de verschillende voertuigen zeer groot is (wel tot een factor 10).
Slechts één dieselvoertuig met EGR in combinatie met LNT technologie presteerde
naar verwachting.
Voor de emissiecomponenten 00, THC en PM is er voor alle technologieën geen
sprake van praktijkemissies die hoger zijn dan de emissies in de typekeuring.
De resultaten van dit onderzoek worden bevestigd door externe bronnen en
metingen van de Technische Universiteit in Graz. Alhoewel het aantal gemeten
voertuigen beperkt is, is het niet de verwachting dat het beeld zal veranderen als er
meer testresultaten beschikbaar komen. Een en ander betekent dat de NOx
praktijkemissies van Euro 3,4,5 en 6 voertuigen niet wezenlijk verschillen.
—

Resultaten literatuuronderzoek:
Vier Europese bronnen met emissieresultaten van Euro 6 voertuigen zijn
geraadpleegd. Het betreft publicaties van de volgende organisaties: ADAC (D),
AECC(B), JRC(I) en TOl(N). De resultaten van deze studies komen redelijk tot
goed overeen en stroken in grote lijnen met de praktijkmetingen van TNO en TUG.
Bij een omgevingstemperatuur van 25 00 bedraagt de NOx praktijkemissie van
dieselvoertuigen 400-500 mg/km (5-6 keer limietwaarde). Voor de
emissiecomponenten 00, THC en PM is er geen sprake van overschrijding.
Eisen voor praktijkemissies in toekomstige Euro 6 wetgeving:
Vanaf 1 september 2014 moeten alle nieuw ontwikkelde personenwagens voldoen
aan de eisen van fase 1 van Euro 6. Deze wetgeving bevat nog geen specifieke
eisen over de emissies in de praktijk en dwingt dus niet af dat dieselauto’s het ook
in de praktijk goed doen. Lage praktijkemissies voor NOx kunnen wel worden
afgedwongen door aanvullende wetgeving met NOx emissies die in de praktijk
moeten worden gehaald. Zolang dit niet gebeurd is er geen perspectief op lage
praktijkemissies voor NOx van dieselpersonenauto’s.

TNO report 1 TNO 2013 Ri 18911 5 December 2013

5/42

Op dit moment wordt in Brussel gewerkt aan de tweede fase van Euro 6, waarin
dergelijke emissie-eisen voor de praktijk worden gedefinieerd. In aanvulling op de
typekeuringstest in het laboratorium moet het voertuig voor fase twee Euro 6 ook op
de weg met mobiele testapparatuur (PEMS) worden beproefd. Het is de
verwachting dat door het stellen van praktijkeisen NOx-emissies aanzienlijk zullen
dalen. Bij Euro-Vl vrachtwagens heeft de invoering van een nieuwe testmethode
met mobiele meetapparatuur op de weg ook tot een aanzienlijke daling van de
NOx-emissies geleid.
De Europese Commissie is voornemens om de tweede fase van Euro-6 in
september 2017 in werking te laten treden. Vanuit de auto-industrie zijn er echter
wensen voor uitstel naar een latere datum.
De voertuigtechnologie is echter beschikbaar om voertuigen aan fase twee eisen
van Euro-6 te laten voldoen. Dit kan worden gerealiseerd door effectieve
toepassing van EGR in combinatie met SCR of LNT systemen. Reeds in 2010 zijn
metingen verricht aan pre-Euro 6 dieselvoertuigen, waarbij goede NOx prestaties
werden vastgesteld. Vermoedelijk is een optimalisatieslag van kosten de reden
geweest dat de huidige Euro 6 voertuigen in de praktijk slechter presteren.

TNO report 1 TNO 2013 Ri 1891 1 5 December 2013

6142

Summary
Results of a vehicle emission test program on behalf of the Dutch Ministry of
Infrastructure & the Environment show higher real world NO emissions of Euro 6
diesel passenger vehicles than would be expected on basis of the Euro 6 Type
Approval emission levels. The Euro 6 type approval limit value comes into force in
2014 and it aims at a substantial reduction of pollutants of passenger cars and light
commercial vehicles.
In spite of the tightening of the Euro 5 NO Iimit value (180 mg/km) to Euro 6 (80
mg/km) real world NO emissions of tested Euro 6 vehicles are approximately 500
mg/km and they are equal approximately to Euro 4 and Euro 5 diesel passenger
vehicles.
On behalf of the Dutch Ministry of Infrastructure and The Environment TNO
investigated real world emission performance of Euro 6 diesel passenger cars. The
results of the test program are the basis of the determination of Dutch emission
factors. Furthermore the Ministry requested TNO to define measures for Iow real
world emissions which are in line with type approval emissions.
The vehicle emission tests are carried out in a laboratory on a chassis
dynamometer as well as on the road with a portable emission measuring system
(PEMS). All these Euro 6 diesel passenger cars comply with the NO type approval
limit values of 80 mg/km. However real world NO results are approximately 6 times
higher. Only one vehicle performed under real world conditions well below (25-75
mgfkm) the NO limit value.
Structure of the study:
This study is based 0fl emission test results of diesel passenger cars. In 2010 and
2013 the tests were carried out in a laboratory and on the road. The test results are
reviewed on the basis of the applied aftertreatment technologies. Furthermore Euro
6 emission factors are determined and compared with former emission factors.
All test results are compared with test results of a number of European research
institutes. Finally on basis of these results recommendations for low real world
emission test procedures are made for future legislation.
Cause for concern:
In spite of the continuous tightening of the NO type approval-limit values from Euro
1 to Euro 6, last decade the NOx emission factors on the motorway have been

more or less stable (400-600 mg/km). However there is a reduction in city traffic
(from 1000 200 mg/km) but this still is more than the type approval limit value of
80 mg/km.
—

TNO report TNO 2013 Ri 1891

7142

5 December 2013

r-

• urban

M motorway

—

Type Approval Limit value

1,20

1.i_

Euro1

Figure 2:

Euro-2

Euro-3

Euro-4

EuroS

Euro-t

pre-Euro-6

NOx emission factors in the city and on the highway and type approval limit values of
diesel passenger cars.

In 2010 some emission tests were carried out on the first Euro 6 diesel passenger
cars. These pre Euro 6 vehicles which were available for the US-market performed
better than the current Euro 6 production models.
Up to 2013 only a few Euro 6 diesel vehicles were sold, and mainly in the upper
market segment. Small new diesel vehicles are still not equipped with Euro 6
technology. However, they must comply to type approval values in 2014 and all new
vehicles must comply one year later. Presumably, the smaller diesel vehicles will be
equipped with cheap technology. This may lead to different (higher!) real world
emissions and adjustment of current Euro 6 emission factors.
The test results of Euro 5 and 6 petrol vehicles certainly show low real world NO
emissions (< 80 mglkm).
Applied exhaust aftertreatment technology is a key element:
Real world NO emissions of Euro 6 diesel passenger cars vary very strongly.
Dependent on the test conditions and vehicle technology the spread is 10% to
1000% of the limit value. This is mainly caused by the type, the functionality and the
control strategy of the exhaust after-treatment technology. Available technologies
are EGR (Exhaust Gas Recirculation), SCR (Selective Catalytic Reduction) and
LNT (Lean NOx Trap). Euro 5 as well as Euro 6 vehicles make selective use of
these technologies which take care of NO reduction in the exhaust gases. During
type approval tests the control strategies are active and effective, but during real
world operation the systems can be (partly) switched off.
In this test program the selected vehicles are classified in the upper segments and
equipped with EGR and SCR or LNT technologies. The small Euro 6 diesel vehicles
are still not on the market. These smaller and middle segments will be the bulk of
the total fleet of diesel vehicles and probably they will be equipped with cheaper
technology. Manufacturers only apply EGR-technologies, SCR and LNT
technologies which are able to produce low real world NOx emissions probably will
not be applied widely. Like with Euro 5 diesel vehicles this is a risk for high NO

TNO report 1 TNO 2013 Ri 18911 5 December 2013

8/42

emissions on the motorway. It is expected that real world NO emissions of small
Euro 6 vehicles will be on the same level as the real world NO emissions of Euro 5
diesel vehicles.
Vehicle emission test resuits of TUG and TNO:
All Euro 6 diesel vehicles comply with their NOx type approval limit values of 80
mg/km but the effect of the applied technologies under real world conditions is
restricted. This is measured in tests which are more related to daily use. On the
chassis dynamometer this is the CADC-test and on the road tests are performed in
the city, rural roads and motorways. Again the real world N0 emissions are on
average 400-500 mg/km. In road tests on public roads (city, rural, motorway)
average N0 emissions of 550—800 mg/km are measured, this 7-10 times the type
approval value. Furthermore, the spread of the different vehicles is huge (up to 10
times). Only one vehicle with EGR and LNT technology performed under real world
conditions below the type approval limit value of 80 mg/km.
For all technologies CC, THC and PM real world emissions are below their type
approval limit values.
The results of this test program are confirmed by literature and the test results of
the Technical University of Graz (TUG). Although the number of tested vehicles is
low it is not expected that these emission factors will change in case of more
available test results. This means that real world NOx emissions of Euro 3,4,5 and 6
vehicles not really differ.
Resuits literature research
Four European sources with emission test results of Euro 6 vehicles have been
investigated. It concerns publications of ADAC (D), AECC(B), JRC(l) en TOI(N).
The results of these studies agree reasonably with the real world test results of
TUG and TNO. At ambient temperatures of 25 °C the real world NO emission of
diesel passenger cars are 400-500 mg/km (5-6 times of the type approval limit
value). The CC, THC and PM real world test results do not exceed the type
approval limit values.
Requirements for future Euro 6 emission legisiation:
On September ist, 2014 all new vehicle types must complywith Euro 6 stage 1
regulation. This regulation does not contain specific requirements for real driving
emissions (RDE) and does not force manufacturers to achieve low real world
emissions. However, low real world NO emissions can be reached with appropriate
legislation with real world N0 emission requirements. As long as this legislation
comes not into force low real world NO emissions of diesel cars will probably not
be realized.
Currently stage 2 of Euro 6 legislation is under construction in Brussels which will
contain requirements for real world emissions. In addition to chassis dynamometer
tests vehicles will be tested on the road with PEMS equipment. It is expected that
real world emission requirements will lead to lower real world NO emissions of
diesel passenger cars.
In case of Euro VI trucks the enforcement of new test methods with mobile test
equipment has led to a strong reduction of real world NO emissions.
In September 2017 the European Commision resolves the enforcement of phase 2
of the Euro 6 legislation but the automotive industry prefers to postpone this.
However, the Euro 6 phase 2 technology is already available. Low real world NOx
emissions can be reached by application of EGR technology in combination with

TNO report TNO 2013 Ri 18911 5 December 2013

SCR or LNT technology. In 2010 lower NO emissions were already measured.
Presumably an optimization of costs of aftertreatment technologies causes the
worse performance of Euro 6 vehicles in real world operation.

9/42

TNO report ITNO 2013 R11891 15December2013

10 /42

Contents
Samenvatting

2

Summary

6

1
1.1
1.2
1.3

Introduction
Background
Aim and approach
Stucture of the report

11
11
12
12

2
2.1
2.2
2.3

Method
Tested vehicles
Test methods and test cycles
Vehicle emission factors

13
13
14
18

3
3.1
3.2

Emission reduction technologies
Petrol vehicles
Diesel vehicles

20
20
20

4
4.1
4.2
4.3
4.4
4.5

Investigations of public data
ADAC test results
TOl test results
AECC test results
Joint Research Centre data
Conciusions public data

23
23
23
24
28
29

5
5.1
5.2

Experimental resuits
TNO results
TUG data and results

30
30
35

6

Discussion

38

7

Conclusions

40

8

References

41

9

Signature

42

Appendices
A TNO chassis dynamometer test results
B Determination of emission factors

11/42

TNO reportlTNO 2013 R11891 15December2013

Introduction
1.1

Background
To minimize air pollutant emissions of light duty vehicles the Euro emissions
standards were introduced in 1992. The Euro emissions standards becoming more
stringent in the course of time. Currently produced light duty vehicles needs to
corn ply with the Euro 5 standard. The Euro 6 standard will become mandatory in
2014. The standards apply for both spark ignition engines and for compression
ignition engines and includes the following gaseous and particulate emissions:
CO (carbon monoxide)
THC (hydrocarbons)
NO (nitrogen oxides)
PM (particulate mass)
PN (particulate number)
As a result of the Euro emissions standards the pollutant emissions decreased a lot
during the type approval test the past decade. However, some emissions under real
driving conditions differ a lot from type approval emissions. The real driving NO
(nitrogen oxides) emissions of diesel vehicles are currently the largest issue with
2 concentration exceeds the limits at
regard to pollutant emissions. The ambient NO
numerous road-side locations in The Netherlands.
—

—

—

—

—

TNO performs emission measurements within the in-use-compliance program for
light duty vehicles” on behalf of the Dutch Ministry of lnfrastructure and the
Environment. Whereas in the early years, 1989-2000, many standard type approval
tests were executed, in recent years the emphasis has shifted to the gathering of
real world emission data on various nonstandard driving cycles. In the current
program multiple Euro 6 diesel passenger cars are tested.
TNO develops annually updated vehicle emission factors based on the performed
emission measurements, ernission factors represent real world emission data for
various vehicle types and different driving conditions. Vehicle emission factors are
used for emission inventory and air quality monitoring. TNO is the sole supplier of
primary data for this purpose in The Netherlands.
The emission factors for NO emissions of Euro 5 diesel passenger cars were a lot
higher than expected, see Table 1. The NO emission factors of Euro 5 are in most
cases even higher than Euro 4.
Table 1: Emission limits and emission factors for diesel passenger cars

Emission
standard
Euro-1 (1993)
Euro-2 (1996)
Euro 3 (2000)
Euro 4 (2005)
Euro 5 (2009)
Euro 6 (2014)
*NO+ HC

Emission limit
NO [g/km]
0.97*
0.7*
0.5
0.25
0.18
0.08

City
0.73
1.02
0.89
0.51
0.63

Emission factor NO
[glkm]
Rural
0.45
0.55
0.55
0.38
0.34

Highway
0.56
0.5
0.54
0.39
0.61

TNO report 1 TNO 2013 R11891 15December2013

12 /42

In this report the first results of Euro 6 diesel passenger are discussed. Preliminary
Euro 6 emission factors, used in previous years for prognoses are in between 0.08
g/km (80 km/h speed limit motorway) and 0.22 g/km (heavy congestion).

1.2

Aim and approach
The objective of this research is to assess the real world emission performance of
Euro 6 diesel passenger cars and to provide emission factors for this category.
In order to obtain a more comprehensive understanding of the emission
performance, both measurements of TNO and TU Graz are evaluated as well as
the available public data.
Emission measurements are performed with Euro 6 compliant vehicles (early
models). Both chassis dynamometer and PEMS (Portable Emissions Measurement
System) measurements are performed. On the chassis dynamometer various real
driving cycles are used.

1.3

Structure of the report
The project contains a literature survey, an experimental test program and an
emission modelling program.
Chapter 1 describes the introduction, the aim and the approach. In chapter 2 the
applied vehicles, testing methodologies and emission reduction technologies are
described. In chapter 3 the emission reduction technologies are reported. In chapter
4 the available public data are described. In chapter 5 the experimental results are
given and in chapter 6 the determination of the emission factors is reported.

TNOreportlTNO2Ol3Rll89l

2

13/42

5December2013

Method
Available public data or publications are investigated and several Euro 6 vehicles
are tested. These measured test results are the basis for the determination of the
emission factors.

2.1

Tested vehicles
The tested vehicles are early models because Euro 6 is not yet mandatory (will
become mandatory in 09-2014). Only compression ignition (diesel) vehicles are
tested due to the fact that there are no expected direct issues with spark ignition
(gasoline) vehicles regarding NO emissions.

2.1.1

TNO tested vehicles
The tested vehicles by TNO are either provided by the official Dutch importers or by
private owners. In all cases the vehicles have exceeded the minimum requirement
of 3.000 driven kilometres. TNO tested Euro 6 compliant vehicles in 2010 and in
2012/2013.
Table 2 shows the tested vehicles, the character indicates the brand, the number
indicates a specific vehicle.
Table 2:
veh: H2

veh: H3

veh: A2

veh:E4*

veh: H4

veh: H6

Veh: E6

Veh: Ji

Veh: J2

[kW]

>150

>150

>150

100125

125150

100125

100125

100125

100125

Icm3J

>2000

>2000

>2000

1750-

1750-

1750-

1750-

1750-

1750-

2000

2000

2000

2000

2000

2000

[km]

2354

16634

9466

±9400

10965

28376

26200

20100

11616

Diesel

Diesel

Diesel

Diesel

Diesel

Diesel

Diesel

Diesel

Diesel

Vehicle 3

-

Engine Power class
Engine capacity class

TNO tested vehicles

Odometer
Fuel
Inertia
Emission class
Type
Vehiclesclass

-

[kg]
-

-

1700

1930

2040

1590

1590

1470

1590

1590

1590

Euro 6

Euro 6

Euro 6

Euro 6

Euro 6

Euro 6

Euro 6

Euro 6

Euro 6

Sedan

Sedan

Sedan

Sedan

Station

Station

Sedan

MPV

MPV

Ml

Ml

Ml

Ml

Ml

Ml

Ml

Ml

Ml

2013

2013

2013

2013

EGR+
SCR

EGR

EGR

Date

2010

2010

2010

2010

2012

Emission technology

EGR+
SCR

EGR+
LNT

EGR+
SCR

EGR+
LNT

EGR+
SCR

EGR+
LNT

Prototype
or for
USA
market

Prototype
or for
USA
market

Prototype
or for
USA
market

Prototype
or for
USA
market

Production
vehicle

Production
vehicle

Remark

Production Production Production
vehicle
vehicle
vehicle

*Three identical vehicles

The tested four vehicles in 2010 were prototypes or were meant for the USA
market, all these vehicles are relatively large. In 2012 and 2013 five production
vehicles are tested, also this vehicles are relatively large vehicles. The two vehicles
of brand H are of the same model but with a different engine. The two vehicles of
brand J are identical model and types. Furthermore the availability of Euro 6
compliant vehicles are still very scarce, especially for the compact cars.

14/42

TNO report 1 TNO 2013 Ri 1891 1 5 December 2013

2.1.2

TUG tested vehicles
TUG IVT is within Europe, besides TNO, the second party with an substantial test
program for real world emissions of passengers cars. The PHEM emission model is
used to generate the HBEFA emission factors, from this data, for a number of
European countries, such as, Germany, Switzerland, Austria, and Sweden. The last
years, with the availability of Euro 6 vehicles, these vehicles were incorporated in
the test program. The current status is given in the table below:
Table 3:

Available instantaneous emission data on Euro 6 diesel passenger cars at TUG.

Vehicle make and model
Prototype from US market
Prototype from US market
Serial production EU6
Serial production EU6
Serial production EU6

Vehicle lD
D6_v01
D6_v02
D6_v03
D6_v04
D6_v05

2.1.3

Rated power
[kW]
180
180
180
1 10
125

Lab
TUG/chassisdyno
TUG/chassisdyno
TUG/chassisdyno
TUG/chassisdyno
TUG/PEMS

Other parties
JRC is the third party with a test program for real-world emissions. However, there
seems to be no systematic program for in-service conformity. Both the selection of
vehicles as the test cycles are not controlled, to ensure a proper comparison
between vehicles and Euro-classes, needed for emission inventories. The program
seems designed to validate methodology rather than vehicles.
Other parties like ADAC, AECC and TOl have tested the same kind of vehicles as
TNO and TUG. These test programs are limited, yet consistent. ADAC has a longrunning program of vehicle testing for consumers. The TOl program is designed to
provide insight in real-world emission of new technology.

2.2

Test methods and test cycles
Both chassis dynamometer and PEMS (Portable Emissions Measurement System)
measurements are performed in various test cycles.

2.2.1

Chassis dynamometer testing
The vehicles are tested according to the official test procedure (UNECE Reg 83)
and by using different driving cycles with warm or hot start conditions. The following
regulated emissions were measured: CO (carbon monoxide), THC (total
hydrocarbons), NO (nitrogen oxides), PM (particulate mass) and PN (particulate
2 (carbon dioxide) is measured. Table 4 gives an overview
number). Additionally CO
of the used measuring methods.
Table 4:

Measurement principles

Component
CD
HC
NO
2
CO
PM
PN

Analyse
NDIR, Non Dispersive lnfrared
Heated Flame lonization Detection HElD
Chemo Luminescence (CLA)
NDIR
Gravimetric
Condensation Particle Counter (CPC) with Volatile Particle RemovercVPR)

TNO reportiTNO 2013 R11891 5December2013

15 /42

For the tests regular diesel is used, not reference fuel, the influence of reference
fuel on emissions is expected to be relatively small and in addition under real world
conditions there is also no reference fuel applied.
Road bad settings were for each vehicbe provided by the manufacturer. 1f
necessary also a chassis dynamometer test mode’ was activated in order to avoid
problems with start stop, ESP, etc. In some cases the manufactured was present
during the tests.
Used driving cycles
The folbowing driving cycles are used to assess the emission performance of the
Euro 6 vehicles:
—

—

—

NEDC (New European Driving Cycle)
The NEDC (see Figure 3) is used for the official type approval, during this test
the emissions needs to comply with the applicable limit. The NEDC consist of
the UDC (Urban Driving Cycle) and the EUDC (Extra Urban Driving Cycle).
Officially the NEDC begins with cold start. The emission resuits of the NEDC
with cold start are used to check whether the vehicle complies with the Euro 6
limit and to check if the vehicle is technically in good condition. Some vehicles
are additionally tested over a NEDC with a hot start to gain more information
about the emission performances.
The NEDC pattern is not dynamic and does not look like real world driving. The
largest part (in time, not in distance) of the NEDC is urban driving, this is a
disadvantage for heavy and high-powered vehicles. The NEDC is relatively
short (±11 km), as a result the cold start effect is quite large. During the cycle
the engine loads are very low, engine efficiencies at low engine boads are
mostly not optimal.
CADC (Common Artemis Driving Cycle):
The CADC (see Figure 4) is a cycle which represent real world driving better
than the NEDC, however, the CADC is not part of the official type approval
procedure.
The cycle consists of an urban, rural and motorway part. For the motorway part
there are two possibilities, a maximum speed of 130 km/h or 150 km/h. In this
report the results of the CADC with 130 km/h motorway part are reported.
A cold and hot start are both possible with the CADC, in this report the CADC
with hot start is for most tested vehicles shown. In the most recent tests also
CADC’s with cold start are performed, during these tests a second urban part is
driven directly after the motorway part, the result is a CADC with a cold and hot
urban part.
The CADC is more dynamic and reach higher speeds than the NEDC.
The cycle is a lot longer than the NEDC (±45 km), hence the relative cold start
effect is not very large on the total emission.
WLTC (Woridwide harmonized Light duty driving Test Cycle):
The currently European used type approval procedure and test cycle (NEDC)
for light duty vehicbes are not worldwide accepted and produce emission results
(in particular C0
2 and NON) that do not correspond very well to real world
emission results. An important point of discussion of the current procedure is

TNO report 1 TNO 2013 R11891

16 / 42

5December2013

the driving cycle. Currently a new woridwide harmonized type approval
procedure for light duty vehicles is under development which involves a new
driving cycle.
The WLTC (see Figure 5) consists of four parts: low, medium, high and extra
high. When the cycle is approved as part of official legislation it most likely
begins with a cold start. In this program the WLTC is mostly performed with a
hot start and in some cases with a cold start.
The cold start effect is lower than with the NEDC because of the Iength of cycle
(±45 km). The WLTC is more dynamic and reach higher speeds than the
NEOC, however, t is less dynamic than the CADC.
150

125

100
75
t,

0

>

50

25
0
200

400

600
Time [s]

Figure 3:

NEDC (New European Driving Cycle)

800

1000

1200

TNO report TNO 2013 R11891

17 / 42

5 December2013

150

125

-t

100

E
.,

75

0

0

>

50

25

0
0

2000

1000

3000

Time [s]

CADC (Common Artemis Driving Cycle)

Figure 4:

150

125

100
E
E
.;.

>

75

50

25

0

300

600

900

1200

1500

1800

Time [si

Figure 5:

WLTC_v5 (Worldwide harmonized Light duty driving Test Cycle)

TNO reportlTNO 2013 R11891 15December2013

2.2.2

18142

PEMS testing
With two Euro 6 vehicles (E6 and Ji) measurements with PEMS (Portable
Emissions Measurement System) are performed. PEMS tests are performed on the
road under real world conditions. With the PEMS equipment of TNO It is possible to
measure CO, CO
, HC and NO emissions in g/km. The vehicle is fully loaded
2
during PEMS tests because two persons are needed (1 driver, 1 eng meer) and the
equipment (inciuding generator) weighs approximately 200 kg.
All kind of driving patterns are possible with PEMS. In order to be able to compare
tests with each other, TNO always drives a reference trip’. The reference trip
consist of urban, rural and highway driving. Additionally some other trips are driven:
constant speed, urban driving and highway driving, see table below for details.
Table 5: PEMS trips

Trip type
Reference
Constant speed
Urban
Highway
2.3

Length [km}
72
Several
25,5
90

Duration [5]
5000-6000
300-450
3600-4100
3450-3650

Average speed [km/h]
43-5 1
50,80,100,120,130,140,150
23-27
89-91

Vehicle emission factors
Emission factors for Euro 6 will be preliminary. However, new emission factors are
needed as the current factors, based on the expectation of successful emission
control in combination with the Euro 6 emission limits, are no Ionger tenable with
the currently available measurements. The new emission factors are larger than the
current estimates, but will probably be slightly lower than the values of next year
when a substantial group of Euro 6 vehicles and models can be measured. The
expectation is based on the experiences with the introduction of Euro 4 and the
introduction of Euro 5. In both cases the initial expectations were not met, and the
NO emissions remained at more or less the same levels as before.
The current estimates for the diesel Euro 6 NO and NO
2 emission factors are given
in the table below. The table contain both the emission factors for SRM1 (including
motorway average) and the SRM2 (the detailed motorway emission factors).

TNO report 1 TNO 2013 Ri 1891

5 December 2013

19/42

Table 6 Preliminary emission factors for the air-quality model (SRM1 and SRM2)

[mg/km]
urban

emission estimate

NOx

2
NO

Congested

379

119

Normal

237

71

free-flow

252

69

rural

Normal

202

53

motorway

Average

425

129

Congested

377

132

80 km/h

260

76

100 km/h control

387

122

100 km/h
120 km/h

394

123

437

131

130 km/h

468

138

Advanced NOx reduction technologies are needed to comply with the Euro 6 NOx
limit value. To provide better understanding of these technologies the most common
used reduction technologies are identified and shortly described in chapter 3.

TNO reportlTNO 2013 R11891 15December2013

3

Emission reduction technologies

3.1

Petrol vehicles

20 /42

The Euro 6 emission limit values for light duty vehicles with spark ignition engines
(petrol engines) are equal to Euro 5 limit values. Euro 5 petrol vehicles show
already good real world (pollutant) emission performances. The three-way catalyst
in combination with an accurate air-fuel control is the mainstream technology with
very high reduction rates of 00, THC and N0emissions. The last few years
engines with direct fuel injection are often used to obtain higher engine efficiencies
(and lower C02 emissions). The disadvantage of direct fuel injection is the
possibility of higher PN emissions which will possibly require extra emission
reduction technologies like a gasoline particle filter (GPF).
3.2

Diesel vehicles
The Euro 6 emission N0 limit values (80 mg/km) for light duty vehicles (class Ml)
with compression ignition engines are more stringent than the Euro 5 limit values
(180 mg/km). Under real world conditions the N0 emissions of Euro 5 diesel
vehicles are often much higher than during the type approval test. Particulate
emissions and 00 and HO emissions of Euro 5 diesel vehicles are under control
under real world conditions as a result of the applied DPF (diesel particulate filter)
and oxidation catalyst.
To reduce N0 emissions different technologies can be used. The mainstream
applied reduction technology for Euro 5 is EGR (exhaust gas recirculation).
To comply with the Euro 6 limit more advanced technologies are needed. The
following technologies are most used in combination with EGR:
lmproved EGR (cooled low and high pressure EGR).
Reduced engine compression ratio in combination with high pressure EGR.
SOR (selective catalytic reduction) in combination with high pressure EGR.
LNT (Lean NO Trap) in combination with high pressure EGR.
—

—

—

—

Active (engine) control is needed for N0 reduction with EGR, SOR and LNT
systems. The N0 reduction strongly depends on the engine and EGR maps and
SOR and LNT control.
lmproved EGR (Exhaust Gas Recirculation)
N0 emissions are mainly produced at high pressures and temperatures during the
combustion. With EGR (cooled) exhaust gas is recirculated back to the combustion
process. Due to the recirculated exhaust gas there is less oxygen available for
combustion, as a result the combustion (peak) temperatures lowered, hence N0
emissions decrease. The efficiency of EGR depends on the EGR rate (the amount
of recirculated exhaust gas) and its temperature. The possible EGR rate depends
on various parameters (such as engine bad) and needs to be controlled precisely.
The disadvantage of EGR is the increase of the PM emissions (engine out) and
increase of fuel consumption and the possible contamination of the inlet trajectory.
A higher EGR rate causes lower N0emissions but also higher engine out PM
emissions. Due to higher engine out PM emissions the DPF needs to regenerate
(combustion of the stored particles in the DPF) more often.

TNO reportTNO 2013 R11891 15December2013

21/42

For Euro 5 vehicles high pressure’ cooled EGR is most often used. With high
pressure EGR the exhaust gases are guided and cooled from upfront the exhaust
turbine to the inlet trajectory of the engine.
To comply with the Euro 6 limit small diesel vehicles can be equipped with an
advanced or improved EGR system without application of NO aftertreatment
systems. lmproved EGR is the combination between cooled low and high pressure
EGR. With low pressure EGR the exhaust gases are guided from after the exhaust
turbine and DPF to upfront the nIet turbine (ambient pressure). The advantages of
low pressure EGR are better cooling possibilities (enables higher EGR rates and
operation at higher engine bad conditions), less contamination (because of the
filtered exhaust gas) and better mixture with the fresh air. However, there is a risk of
condensates within the EGR- and intercooler with strongly cooled EGR, the
condensates can possibly cause maintenance problems. Also the combination with
high pressure EGR is still needed for proper reaction on engine bad variations.
Reduced eng me compression ratio
As mentioned in the previous paragraph high pressure and temperature during the
combustion cause high NO emissions. By reducing the engine compression ratio
peak combustion temperatures and pressures are lowered and the ignition delay
will increase, hence less NO emissions are produced.
The compression ratio is typicalby lowered from 17-1 8,5 to +14.0. The disadvantage
of lowering the compression ratio is a decrease in engine efficiency (and thus
higher fuel consumption) and the HC/CO control will become more chalbenging.
Combination with EGR is needed to fulfill the Euro 6 limit.
Injection timing
The timing of the fuel injection in the cylinder has a substantial influence on the NO
emissions. A delayed injection will reduce the engine efficiency, but, at the same
time it will yield a reduction of the NO formation and emission.
SCR (selective catalytic reduction)
A SCR system is the combination between a catalyst and the injection of urea
) which
3
upfront the catalyst. Above ±190C the urea is converted to ammonia (NH
3 into N
2 and
reacts with N0 in the SCR-catalyst. The catalyst converts N0 and NH
0. However, the temperatures of diesel exhaust gases are relative low and the
2
H
SCR catalyst needs a temperature of approximately 190 to 500C to work properly,
therefore the vehicle needs to be warmed up before the SCR system is working
properly. Short trips in the city with low engine loads are therefore not optimal for a
SCR system, hence the combination with EGR is necessary to comply with the
Euro 6 limit values.
The AdBlue (urea + water) is stored in a separate tank in the vehicle and needs to
be refilled during service intervals.
LNT (Lean NO,, Trap)
The Lean N0 Trap (or LNC, Lean NO,,, Catalyst) reduces NO,, emissions by a
frequent cycle of NO storage and release due to catalytic reaction by applying
periodic lean and rich air/fuel mixtures. During lean air/fuel mixture period NO,, is
stored, when the Trap reach the max capacity a rich mixture is used to convert the
2 en 02.
NO emissions into N

TNO reportTNO 2013 R11891 15December2013

22 /42

The LNT needs to have a temperature between approximately 25O-4OQC to work
properly. Dependent of the NO conversion rate and the specifications of the
catalyst an increase in fuel consumption of 1 to 4% is possible. With dynamic
engine loads and a cold engine the LNT performs not very efficient. Most deal
conditions are static or low engine loads and a warm engine. The combination with
EGR is necessary to comply with the Euro 6 limit values.

23 /42

TNO reportiTNO 2013 R11891 15December2013

4

Investigations of public data
Four external publications of Euro 6 real world emissions were found and
investigated.

4.1

ADAC test resuits
ADAC tested 7 Euro 6 vehicles [ADAC 2011]. In Figure 6 it is shown that all Euro 6
vehicles comply in the NEDC Type Approval test with the NOx limit of 80 mg/km.
However a NEDC test with hot start resuits in higher NOx emissions, some vehicles
emit 350 mg/km. Furthermore these vehicles emit on the highway 150 1100
mg/km (average appr. 500 mg/km).
2
ADAC states: “Euro 6 diesel vehicles must also effectively reduce NOx and NO
emissions in off-cycle conditions (ie. CADC test cycle)”.
—

NOx-Emissiorien im ADAC EcoTest
• Euro-5 ModelI A
•
Model] S
ra Euro-6 Model] A
Model] S
2
-

12

-

10

•

Model]

•

Model]D
Model] E
ModellF
ModelI G

D

•
•

08

C

06

1

S
04

Grenzwert
Euro-5

180 mg&m
02

•

Grerizwert
Euro-6
80 mg/km
-

0.0
NEFZ kalt

NEFZwarm

ADAC BAS

FahrzkluE

Figure 6:

4.2

ADAC Ecotest resuits Euro 5 and 6 vehicles

TOl test resuits

The Institute of Transport Economics in Norway tested 2 Euro 6 vehicles [TOl 2013]
in an urban test cycle. This Helsinki test cycle has a length of 7,8 km and a duration
of 23 minutes and a maximum vehicle speed of 60 km/h. The tests were performed
at -7 °C and + 23 C and started all with a cold and hot engine.

TNO report TNO 2013 Ri 18911 5 December 2013

1,600

-—

---

24 /42

—

1,400
ct NOs (g/krn

7,8km -7’C
kaidstart

1,200
1,000

• NOx(g,’kml
7,8 km-TC

0,800

vCrmstart

0,600

NO,, (g/km)
7,8 km +23’C
kaidstart

0,400

•NOx(gJkm)
7,8km s’23’C
va rm start

0,200
0,000
Toyota Asensis
Euro 5 diesel

1,600

Mazda CX-5
Euro 6 diesel

Toyota Verso 0-Ford Focus Eiiro VW Up Euro 5 Toyota Prius
5 bcnsin
bensin
Euro 5 hybrid
cat Luro 5 diesel

1

• NOs (y/km)
7,8km -7C
kaidstart

1,400
1,200

• NOu lg/km)
1,000

7,8km -7C
sarrnstarl

0800

• NO,, lg/km)
7,8km +23C
kaidstart

0600
0,400

• NOs g/krn)
7,8km +23’C
varmstart

0,200
0,000
Toyota Avensis
Euro 5 diesel

Figure 7:

Toyota Avensis 0- VW Passat Euro 6
Cat Luro 5 dietel
diesel

Toyota Avensis
Euro 5 bensin

Toyota Prius [uro
5 hybrid

Emissions of NOx from six light vehictes tested with the Helsinki city cycle at -7C and
+23C with cold and warm engine start (Source: TOI-Norway)

The resuits of the two Euro 6 vehicles of Figure 7 show NO,, emissions of
approximately 180 780 mg/km. On average the real world NO,, emissions in urban
conditions are 400 500 mg/km.
—

—

4.3

AECC test resuits

AECC, the Association for Emissions Control by Catalyst, conducted a test program
to compare the newly developed World-harmonized Light vehicles Test Cycle
(WLTC) with the current European regulatory New European Drive Cycle (NEDC)
and the cold-start Common Artemis Driving Cycle (CADC) [AECC 201 3a]
Vehicle engines and aftertreatment technologies were selected to cover a wide
range of future systems. Six European commercially available passenger cars were
chosen: three Euro 5 Gasoline Direct Injection cars, two Euro 6 Diesel cars and a
Euro 5 non-plug-in gasoline hybrid car. Investigations on the test temperature were
also conducted by comparing emissions at 25°C and at -7°C. The study isolated
cycle-to-cycle effects on emissions for each vehicle by normalizing the test mass in

TNO report TNO 2013 R11891 15December2013

25/42

all tests to the draft WLTP (Worid-harmonized Light vehicles Test procedure) Global
Technical Regulation (gtr).
NOx emissions measured on NEDC, CADC and cold-start WLTC are shown in
Figure 8. Some NOx emissions results on NEDC are slightly above the regulatory
limit. However, as described earlier in Figure 5, vehicles inertia used in this test
campaign was higher than the value used at type-approval. This may explain the
impact on NOx emissions on NEDC. Except for vehicle C, NEDC and WLTC are
very similar in terms of NOx emissions. Nevertheless, both the Artemis CADC and
WLTC highlight some increase in NOx emissions Page 5 of 10
on the lean GDI car (vehicle C) compared to the regulatory NEDC.
The Artemis CADC also highlights the higher NOx emissions in real-world of current
diesel cars (vehicles E and F). This is in line with other measurements and is being
addressed by the European Commission developing real-driving emissions
provision for the second stage of the Euro 6 legislation.
600

500
E
—..400

E

:

300

200
0

z

100

Euro 5 51 limit

NEDC
IA
Figure 8:

E

cl

CADC
10

WLTC Cold
IE

NOx emissions @ ambient temperature 25 °C (Source AECC)

lnfluence of ambient temperature on NOx Emissions:
As illustrated by Figure 9, NOx emissions of all vehicles increased when cars were
tested at -7C. However, the influence is the largest on diesel cars, which can emit
800 to 1000 mg/km of NOx on NEDC and WLTC. This is more than ten times the
NEDC Euro 6 limit value of 80 mg/km and highlights that without a regulatory
limitation of Diesel NO emissions at low temperature as is currently being
investigated by the European Commission, NO emissions at low temperatures may
not be controlled.

TNO report TNO 2013 Ri 18911 5 December 2013

26 /42

1200

1000
E
•.-, 800
E
.2 600
E
x
0

z

200

0

NEDC
SA
Figure 9:

WLTCCoId

IB

L

NEDC-7C

WLTC Cold -7C

IE

NOx emissions at 25C and -7C on NEDC and CADC (Source AECC)

One of the AECC conclusions is:
CADC emissions results highlighted some higher NO emissions from diesel
vehicles and somewhat higher NH
3 emissions from stoichiometric gasoline cars. As
high NO emissions have also been reported for modern diesel cars in real-driving
conditions, this tends to con firm that CADC is closer to real-world driving than
NEDC or even WLTC. There was little difference for other emissions though,
including C0
.
2
In a second publication [AECC 2013b] four Euro 6 diesel vehicles were
investigated. See vehicles 12, 13, 14 and 19 in Figure 10 up to Figure 13. From
these test resuits it is shown that CO, THC and PM emissions of the Euro 6
vehicles are below all limit values. However the NO emissions of three vehicles in
the CADC test cycle, which represents real world conditions, are 25 572 mglkm
and three sam ples exceed the limit values.
—

27/42

TNO reportiTNO 2013 R11891 15December2013

r

Comparison of CO Emissions on the NEOC & CADC
DIeSel eriglne sehkIe

500
NEOC Limits (Diesel):
Euro3G4Omg/km
Euro4/5/6 500 mgjkm

450
400

350

35

3O0
250
208

E200

192

I i [I fs [ I
js

1

Figure 10.

-

--

3

4

116

11112

17

5

7

10

12

13

14

19

Diesel CC resuits over full NEDC and CADC tests (Source AECC)

Comparison of THC Emissions on the NEDC & CADC
Diesel engirie 5eiiICle
100

NEOC Umits (Diesel)
are framed as (THC.NOxJ.
For comparison the THC
Ilmlt lor petrol engines
St Luro 4/5/6 is 100 rngfkm

90

80

60

50

45

r

4040

E 40

34,

33

30
20
10

Figure 11

[11

20

j

t

i9
22

62

:

20

J ! 1:

Diesel THC results over full NEDC and CADC tests (Source AECC)

19

5December2013

TNO report 1 TNO 2013 R11891

r

28 /42

Comparison of NEDC & CADC PM

• NEOL

•CADC

Oiese enInvehIcIes
40.0

1 Eu.O 3 lhnit

rig[nmethodt

50

350

30.0

2.2

,ri.I

E,jr

nh1h,d)

250

E
20.0
E

—

150

W
F1

E
10.0
D

S0

3.3
0

00

4 a

iFi

Iimt ;‘

1
0.3 0.5 03 0,1 07

0,6

S mk fr

0.2

0.3

—‘

-.

12

13

0.2 0.5 050.7
—

—

14

19

-‘

4

3

1
Furri II

5

6

7

10

liiro t,

‘wQ 4

Diesel PM resuits over full NEDC and CADC tests (Source AECC)

Figure 12:

Comparison of NOxErnissioris ori the NEDC& CADC
DIeI englne vehkI
966

t
900

848

800
,

691

700

676

626

E 600
-

—500
4OO
E
300
200

572

570
Eure

521

r

3

357

•

171

163

152

175

o:L1 [ii

[unS
‘‘

•

Vuhictu 1

Eurn 3,l :

3

4

5

6

7

10

12

13

Euro 4

14
Euro 6

145

19

Figure 13: Diesel NOx results over full NEDC and CADC tests (Source AECC)

4.4

Joint Research Centre data
DG-JRC conducted a test program with one Euro 6 diesel vehicle. Laboratory as
well as real world tests were performed [JRC 2012]. Real world NO emissions
exceed the Type Approval limit values.

TNO reportlTNO 2013 R11891

29 /42

5December2013

“The Euro 6 diesel car shows in the laboratory substantially lower NO emissions
(0.07 +1- 0.004 g/km) than the Euro 4 car9 (0.29 g/km) and the four Euro 5 cars
(0.20 0.04 g/km). More importantly, the Euro 6 car also shows
substantially lower on-road NO emissions (0.21 +1- 0.09 g/km)
than the Euro 4 cars (0.76 +1- 0. 12 g/ km) and Euro 5 cars
(0.71 +1- 0.30 g/km)”.
45

Conclusions public data
All public sources [ADAC 2011], [AECC 2013a] [AECC 2013b] and [TOl 2013]
report for diesel Euro 6 vehicles average real world NOx emissions of 400 500
mg/km @ 25 C. For lower ambient temperatures the NOx emissions are even
higher.
The other pollutant emissions (CO, THC and PM) do not exceed the Type Approval
limit values.
—

For direct injected gasoline Euro 6 engines PN test resuits do not comply with future
standards. It is expected that Gasoline Particulate Filters are needed to comply with
future requirements.

TNO report 1 TNO 2013 R1 18911 5 December 2013

5

30/42

Experimental resuits
In this chapter the test resuits of the emission measurements of TNO, TUG and
from public data are shown.

5.1

TNO resuits
TNO performed chassis dynamometer and PEMS tests, both resuits are shown in
the following paragraphs. Detailed results are reported in Appendix A.

5.1. 1

Chassis dynamometer resuits
issions
Figure 14 upto Figure 16 show the NOemissions ofthetested vehicles in 2010
and in 201 2/2013 over various driving cycles.
Figure 14 shows that the NOemissions over the NEDC with cold start are almost in
all cases compliant with the Euro 6 limit value (only vehicle E6 is slightly higher).
During the CADC test the NO emissions are often a lot higher than during the
NEDC.
Especially vehicle Ji and J2 have extreme high NO emissions in the CADC, the
NOemissions are 5,7 (Ji) and 9,1 (J2) times higher than the Euro 6 limit value,
these emissions are comparable to Euro 5 real world emissions. The NOemissions
during the WLTC are 2,6 and 3,1 times higher than the Euro 6 limit value.
These vehicles have no after treatment to reduce NO emissions but work with a
lowered compression ratio in combination with EGR.
Vehicle E6 shows betters results than vehicle J1 and J2 during both the WLTC as
the CADC, the NO emissions are approximately 2,2 times higher than the Euro 6
limit value. This vehicle has SCR aftertreatment.
Vehicle H4 and H6 show very good results on all cycles, only vehicle H4 exceeds
the limit during the CADC, however, this is caused by a regeneration of the DPF. It
is assumed that these vehicles use a LNT.
In general the 2010 models have better results than the 2012/2013 models.

TNO reportiTNO 2013 R11891 15December2013

c: NEDC cold

31/42

CADC hot

WLTC hot

—Limit
09082013

800

700

Euro 6 production**

600

E 500

uro 6 prototype*

bD

E 400
30O

t

Regeneration

of DPF

200

1
100

0

Figure 14:

fl

Ei
>150kW

>150kW

>150kw

100125kW

125150kw

100125kw

100125kW

100125kw

100125kW

veh: H2

veh: H3

veh: A2

veh:E4

veh: H4

veh: H6

Veh: E6

Veh: J1

Veh: i2

NO emissions per driving cycle

Figure 15 and Figure 16 show the NO emission results per phase during the NEDC
and CADC. In the NEDC the NO emissions are in all cases higher in the urban
phase than in extra urban phase. In some cases also a NEDC with hot start is
performed, it is interesting that vehicle E6, Ji and J2 have higher NO emissions
during the urban phase with hot start than during the urban phase with cold start.
In the CADC this trend is not the same, the urban phase with cold and hot start
differ mostly not very much.
Vehicle Ji and J2 show especially during the CADC motorway part extreme high
emissions, vehicle J2 exceeds even the 1000 mg/km. Also in the urban en rural
phase the emissions are not very good.
Vehicle E6 shows good results during the CADC motorway phase, the SCR system
is working properly during the high speeds. The NO emissions during the urban
phase on the other hand are quit high with more than 400 mg/km.
Vehicle H4 and H6 show very good results on each part of the CADC cycle, only
high emissions are shown during the motorway phase with vehicle H4 due to the
regeneration of the DPF.

TNO reportiTNO 2013 R11891

32/42

5December2013

• NEDC UDC cold

• NEDC EUDC cold

NEDC UDC hot

• NEDC cold total

‘I’NØ

350

Euro 6 procluction**
300

250

Euro6prototype*
E
-

200

1

E
<

0

150

100

gil

Figure 15:

1

-p
Ii

50

I

ii 1

—I

>150kw

>150kw

>150kW

100125kW

125150kw

100125kw

100125kw

100125kW

100125kW

veh: H2

veh: H3

veh: A2

veh:E4

veh: H4

veh: H6

Veh: E6

Veh:J1

Veh:i2

NO emissions per phase in the NEDC

• CADC urban cold

1 CADC urban hot

1 CADC rural

1 CADC rnotorway 130

1 CAD(
09-08-2013

1200

1000

11
Euro 6 productJon
800

E
600
Regeneration

Eurd 6 prototype
1

400

Figure 16:

a iii

>150kw

>150kw

veh: H2

veh: H3

/of DPF

/

Ii 1

iii

_.I

>150kW

100125kW

125150kW

100125kW

100125kW

100125kW

100125kW

veh: A2

veh:E4

veh: H4

veh: Fl6

Veh: E6

Veh: ii

Velt J2

_

0 emissions per phase in the CADC
NO

_

33/42

TNOreportITNO2ol3Rll89l 15December2013

5.1.2

PEMS test resuits
With vehicle E6 and Ji PEMS tests are performed. With vehicle E6 all tests were
successfully performed. Vehicle Ji shows unusual high g/km emissions, further
investigations and tests are needed. Emissions in mass (g/km) of vehicle Ji are
therefore not reported in Figure 17 and Figure 18.
In Figure 17 and Figure 18 the NO
9 emissions of vehicle E6 and earliertested Euro
5 vehicles are shown. Figure 17 shows the absolute (mg/km) emissions and Figure
18 shows the relative (%) emissions with respect to the limits.
Figure 17 shows that vehicle E6 is the best vehicle that TNO has tested, the NO
emissions are especially during high and constant speeds very low (around 80
mg/km) as a result of the SCR system, during urban driving the emissions are stiJl
quit high with +600 mg/km, the same pattern was noticed during the CADC. In the
reference trip the emissions are with 400 mg/km the lowest of all tested vehicles but
it is still a lot higher than the Euro 6 limit.
Figure 18 shows that with respect to the limit the emissions of vehicle E6 are very
high during the urban driving (+ 8 times higher than the limit) and during the
reference trip (± 5 times higher than the limit). At high and constant speeds the
resuits are around the limit.

PEMS measurements
5 Buro 5 diesel vehicles, 1 Euro 6 diesel vehicle
1

09-03 2013

•Urban desel
Constant speed diesel
Highway Euro 6

,tdiesel
Â Highway diesel
• Urban Euro 6

-

-

•Rural diesel
XReference trip Euro 6

-

:. Constant speed Euro 6

1,800

1,600
1,400
1,200
1,000
800
600
400
200
0
20

30

40

50

60

70

80

90

Average speed [km/hj
Figure 17:

Absolute PEMS results for Euro 5 vehicles and vehicle E6

100

110

120

130

140

34/42

TNO report 1 TNO 2013 R11891 15December2013

PEMS measurements
5 Euro 5 diesel vehicles, 1 Euro 6 diesel vehicle
X Reference trip diesel
Highway diesel
•Urban Euro 6

• Urban diesel
Constant speed diesel
AHighway Euro 6
.

TNO
09-08-2013

• Rural diesel
Reference trip Euro 6
::Constant speed Euro6

900%
800%
700%
—

0

Z

600%
500%
400%
300%
200%
100%
0%

Average speed {km/h]
Figure 18:

Relative PEMS results for Euro 5 vehicles and vehicle E6

resuits
2 (glkg) results are used by TNO to
To asses heavy duty vehicles the NO over C0
compare smaller and larger vehicles with each other. When the vehicle has a higher
2 emission), It may emit more NOK. For light duty vehicles this
fuel consumption (C0
is not an usual method yet, but TNO does use this method because now the results
of the vehicle Ji can also be used.
Figure 19 shows that both the Euro 6 vehicles are better than all Euro 5 vehicles,
but compared with a petrol (Euro 5) or heavy duty (Euro VI) vehicle the results are
not very good.

TNO reportlTNO 2013 R11891 15December2013

35 /42

—Veh: E6_EU6_diesel —Veh: i1_EU6_diesel
Veh: 3_EU5_diesel

Veh: 1_EU5petrol

Veh: 1_EU5_diesel

—

—

Veh: 2_EU5_dies&

Heavy Duty_EUVI

———-

0908 2013

10
111

9

8

,..

II

,I
1
i

7
3)

‘.1
-.

1

‘%

._._..

1

t’”

C’1

o(.) 5

—

.

__,

/

oz
3
2

-:

0

.-=ttet—,,

.,——

°

Speed bin [kmlh]

\ \\\

Figure 19: PEMS resuits binned in NO over C0
2

5.2

TUG data and resuits
The HBEFA3.2 emission factors for Euro 6 passenger cars are compiled by the
weli-established approach using the TUG IVT emission model PHEM. In the
HBEFA3.2 the emission standard Euro 6 will be differentiated between first
generation of Euro 6 vehicles (referring to stage Euro 6a and Euro 6b, hereafter and
specified as “Euro 6”) and vehicles which will enter the market based on more
stringent emission regulation expected in 2017 (hereafter and specified as ‘Euro
6c”).
The following chapter describes the data sources and the results for the Beta
version of the HBEFA 3.2 emission factors. Adaptations for the final version may be
done in October 2013.

5.2. 1

Emission data avallable for Euro 6
The PHEM emission maps for Euro 6 have been generated based on instantaneous
emission data available for five vehicles. For this sub-set of the Euro 6 sample the
complete data necessary to set up engine emission maps was available (accurate
instantaneous emission values and engine speed and engine power data). For the
other vehicles measured in the ERMES group at the time of engine map elaboration
only bag data was available.

TNO report TNO 2013 R1 18911 5 December 2013

Table 7:

36/42

Available instantaneous emission data on Euro 6 diesel passenger cars

Vehicle ID
D6_vOl
D6v02
D6_v03
D6_v04
D6_v05

Vehicle make and model
Prototype from US market
Prototype from US market
Serial production EU6
Serial production EU6
Serial production EU6

Rated power
[kW]
180
180
180
110
125

Lab
TUG/chassisdyno
TUG/chassisdyno
TUG/chassisdyno
TUG/chassisdyno
TUG/PEMS

With this first set of engine emission maps for Euro 6 diesel cars emissions have
been simulated for the CADC and for the ERMES cycle. The engine maps were
then calibrated by the ratio of emission levels measured in the CADC on all Euro 6
diesel passenger cars available in the ERMES LDV bag database (Table 7) to the
emission levels simulated. In this process the measured emission data also were
weighted according to the shares of the used engine types in the available data on
new registrations in 2012. For Euro 6 similar sales numbers than for the Euro 5
predecessors were assumed.
Here it has to be mentioned that the Euro 6 vehicles available until the end of the
HBEFA3.2 measurement campaign mainly refer to the premium vehicle segment,
which adds a certain uncertainty to the resulting fleet emission factors.
In addition uncertainties are related to:
• Shares of NO control technologies in the future Euro 6 fleet.
• Level of exploitation of NO reduction potential of these technologies in the
future fleet (e.g. AdBlue may not be dosed at high engine loads by a yet
unknown share of vehicle models if not relevant in the type approval test)

5.2.2

Assumptions for Euro 6c emission behavlour
For Euro 6c vehicle technology a real world emission level (in this context defined
as 1/3 mix of CADC subcycles “urban”, “road” and “motorway”) has been defined
with two times NEDC Euro 6 limits (2*8Omg = l6Omg) due to a mandatory PEMS
test in real drive operation and a emission conformity factor lower than 2. The
emission factors for all other regulated pollutants as well the NO
/ND ratio is
2
assumed as identical similar to Euro 6 (first generation) technology.
In the calculation of the emission factors with the model PHEM furthermore the
following details have been considered (details see full HBEFA report):
•
Updated vehicle parameters (mass, rated power, etc.) to represent the fleet
average Euro 6 vehicle from EU27 new car registrations
• lncreased market penetration of start stop systems
• lnfluence of particle filter regeneration on average emission levels.
Results

Figure 20 gives a comparison for NO emissions simulated with the calibrated
PHEM model for Euro 6 diesel passenger cars in the CADC sub-cycles For
comparison also results for Euro 0 to Euro 5 are plotted. Emission factors for the
HBEFA are computed for different driving cycles and are reported in the HBEFA
report 3.2 The CADC cycle gives a a picture for a well-known test cycle but is
assessed to lead to rather higher emission levels compared to “normal driving”.
.

TNO reportlTNO 2013 R11891 15December2013

37 /42

The actual data suggests a dear NOx reduction under hot driving conditions due to
Euro 6 which is more pronounced for urban driving conditions (— -65%) than in rural
(—-55%) and motorway conditions (—-45%).
1.4

1.2

1

• Euro 0
-

• Euro 1

E
1

1

0.8

0

cv
.40

0.6

• Euro 2
1 Euro 3

1 Euro 4
52b

• Euro 4 D

4fl

2

• Euro 5

0.4
0.275
0i47—

0.2

0

-

urban

Figure 20:

0.263

-

rural

motorway

0.281

o Euro 6

1:

OEuro 6c

Emissions simulated with PHEM for diesel passenger cars in the CADC under hot start
conditions

The NO
/NO ratio found for Euro 6 diesel cars is 35 to 40%. Emission levels of PM,
2
PN and CC is approximately similar to Euro 5. For HO a higher emission level
compared to Euro 5 (ca. factor of 3) was calculated, but on very low absolute level
compared with the emission limit.

CADC

TNO reportlTNO 2013 R11891 15December2013

6

38 /42

Discussion
Both the introduction of Euro 4 and the introduction of Euro 5 followed the same
trend. Petrol passenger cars yielding lower real world emission than the emission
limits, and the diesel passenger cars, showing some initial reduction at the
introduction, have eventually no substantial reduction of the NO emissions. Again a
new Euro-class is introduced: Euro 6. Some vehicles have low real-world
emissions, however, not quite at the level of the emission limit of 80 mg/km. Other
vehicles have emissions at the level of Euro 5, showing no significant improvement
with the new limit.
There is hope of a reduced NOx emission of Euro 6 diesel passenger cars,
however, at the same time the risk there will be no significant reduction. It is
possible to optimize the emission control technology such that type-approval test
will be below emission limit, and, at the same time, show no appropriate low
emissions in other, real-world driving and vehicle usage. Eventually, Real-Driving
Emission (RDE) part of later stages of Euro 6 legislation should solve the problem
of incompatible results of the official test and other test results. In that case,
expected in 2017, the NEDC test alone is no longer the single point of reference for
emission control.
The current emission factors for Euro 6 are halfway between the test results and the
expected emission risk. The risk manifests itself mainly on the motorway. It is
possible that Euro 6 diesel passenger car NO emissions are higher than the
corresponding Euro 5 emissions. In urban and rural conditions it is expected that
Euro 6 emission will remain below Euro 5 emissions, even in the worst case
scenario. This is very likely due to the improved fuel efficiency in these conditions,
and the closer resemblance of these conditions with the circumstances in the NEDC
test.
Different technologies carry different risks. More advanced emission control
technologies such as SCR and LNT will yield risk in technology specific
circumstances, not directly related to driving behaviour but rather with the trip
history, temperature, bad variations, and bow boads. The most common and
important Euro 5 emission control technobogy is EGR. This technology is relatively
inexpensive and likely to be implemented in common compact cars, which dominate
the Dutch vehicle fleet. The associated risk with EGR is at high bad. Hence, at the
moment it is foreseen that in particular these compact cars on the motorway carry a
large risk of high NO emissions. It is already shown that EGR technobogy is
capable of reaching Euro 6 emission limits on the NEDC.
The results are limited, as the number of available vehicle models is limited, and the
analyses of the emissions is preliminary. Based on current results, emission
modelling will have to undergo a transition from so-called “proportional models”
associating emissions with power, velocity, and C0
, towards “risk modelling”
2
identifying the emission control strategy and its associated risks. Only for EGR the
traditional “proportional” approach will hold also for Euro 6. Despite these
limitations, the statistical analysis underlying the approach combined with
appropriate test cycles for real world driving still yields robust results for emission
factors.

TNO report 1 TNO 2013 R11891 15December2013

39/42

In Figure 21 the historical and current NOx emission factors of diesel passenger
cars are shown. In urban traffic t is dear that diesel passenger cars perform better
in time, their NOx emission factor is reduced from 106 to 0,24 glkm. However this
is more than the Euro 6 Type Approval limit value of 008 g/km. The NOx emission
factors on the motorway show a different trend, they have a constant level of 0,40
0,60 g/km (5-7 times the Type Approval limit value).
In time the NOx Type Approval limit values are more than 10 times reduced (from
0,90 to 0,08 glkm). However the emission factors on the motorway didn’t decrease
significantly and the urban emission factors only reduced 4 times (from 1,06 to 0,24
g/km). These numbers show clearly that the gap between Type Approval NOx
emissions and real world NOx emissions increase; this gap is caused by selective
use of NOx reduction systems which can be easily managed by advanced control
systems of the vehicle. In the past emission factors and Type Approval limit values
were at the same level, currently the emission factors are far higher than the Type
Approval limit values.

—

• urban

• motorway

—

Type Approval Limit value

1,20

1,00
E
0,80

0,60

0,40

0,20

0,00
EUro-1

Figure 21:

Euro-2

Euro-3

Euro-4

Euro-5

Euro-6

pre-Euro-6

NOx emission factors and Type Approval limit values of diesel passenger cars

TNO report 1 TNO 2013 Ri 1891

5 December 2013

40/42

7 Conciusions
•

•

•

•
•

•

The range of NO emissions of Euro 6 diesel passenger cars in real-world tests
is very large. In some cases the emissions are one-tenth of the emission limit
value, in other cases tenfold the emission limit value.
The results from TNO are confirmed by other tests and emission modelling in
Europe. In particular the emission factors from TNO are in line with the
preliminary results from TUG.
Different emission reduction technologies exist, each with their own risk of high
emissions. Some of these risks can already be quantified from the limited
testing on the available models.
It is not to be expected that the real-world NO emissions of Euro 6 diesel
passenger cars will be close to emission limit value of the NEDC test.
The lower emission limit values from Euro 3 to Euro 4 and Euro 5 has not led to
a decrease in real-world NO emissions on diesel passenger cars. This
experience over the last ten years gives littie hope for Euro 6 in the absence of
an improved test procedure, or real-driving emission legislation.
It is likely that the simplest and cheapest emission control technology will be
used in compact cars, which are the bulk of the Dutch sales. This signifies a risk
of high NO emissions similar to Euro 5, in particular on the motorway.

TNO reportiTNO 2013 R11891 15December2013

41/42

8 References

[TNO 2006]

Euro VI technologies and costs for Heavy Duty vehicles, The
expert panels summary of stakeholders responses, Gense et.
Al. 2006. 06.OR.PT.023.2/NG

[TNO 2010]

Verkennende metingen van schadelijke uitlaatgasemissies van
personenvoertuigen met Euro 6 dieseltechnologie,
MON-RPT-201 0-02278

[ADAC 2011]

Messungen an Euro 5- und Euro 6-Pkw im ADAC EcoTest

[JRC 2012]

Will Euro 6 reduce the NOx emissions of new diesel cars? e
lnsights from on-road tests with Portable Emissions
Measurement Systems (PEMS), Weiss et. Al.
-

[TOl 2013]

Utslipp fra kjoretoy med Euro 6Nl teknologi

[AECC 2013a]

SAE-paper 2013-24-0154, AECC, Exhaust Emissions from
European Market-available Passenger Cars evaluated on
various Drive Cycles

[AECC 2013b]

Emissions from Euro 3 to Euro 6 light-duty vehicsequipped
with a range of emissions control technologies,
Association for Emissions Control by
Catalyst, Belgium

TNO report 1 TNO 2013 R11891 15December2013

42 /42

9 Signature
Delft, 5 December 2013

Project Lider

Author

TNO reportiTNO 2013 R11891 15December2013

A

Appendix Al 114

TNO chassis dynamometer test resuits
Corn pliance with the Euro 6 limit value:
TNO tested vehicles in 2010 and in 2012/201 3. The upcorning tables show the
ernission resuits over different driving cycles of the five tested vehicles in 2012 and
2013. The tested vehicles in 2010 were prototypes or were meant for the USA
market, there these resuits are less relevant than the tests of 2012 and 2013.
The Table 8 up to Table 12 show that almost all vehicles are compliant with the Euro 6
limit value for each emission type during the NEDC with cold start. The following
vehicles exceeding the limit:
H4 exceeds the PN lirnit with almost 50%, the PN emissions in the other cycles
are also relatively high, no technical defects were found.
E6 exceeds the NO lirnit with 22,5%, this is considered as marginal.
J2 exceeds the CO limit with 32%, this is considered as marginal, in addition, in
other tests the CO emissions are no issue, no technical defects were found.

—

—

—

Also during the cycles other than the NEDC with cold start the CO, PM and PN
(except vehicle H4) ernissions are all lower than the Euro 6 limit value. THC + NO
emissions are often higher than the limit value, this is caused by the high NO
emissions, THC ernissions are not an issue. The high NO emissions are discussed
in the next paragraph.
The C0
2 emissions during the NEDC with cold start are in all cases higher than
during the type approval test, the deviation varies between the 3 and 17%. This
deviation is considered as a problem but t is not further addressed in this report as
it is not a pollutant’ ernission.

Appendix A 2/4

TNO reporti TNO 2013 R11891 15December2013

Table 8: Resuits vehicle H4

Emissions
vehicle H4
CO
C02
NOx
THC+NDx
PM
PN
Fuel
consumpti
0fl

Limit
(Euro
6)

NEDC
cold

500

36

124*

NED

CADC
cold**

CADC
hot

WLTC
cold

WLTC
hot

x

268

269

131

122

128

x

150

149

135

131

80

12

x

205

201

31

17

170

35

x

272

273

107

94

4.5

0.4

x

2.2

2.2

0.1

0.2

[-/km]

6.OE+1
1

8.9E+1
1

x

2.6E+1
2

2.8E+1
2

2.3E+1
1

3.8E+1
0

[1/100
km]

47*

4.76

x

5.61

5.58

5.05

4.89

Unit
[mg/k
m]
[gfkm]
[mg/k
ml
[mg/k
m]
[mg/k
m]

*Type approval value
**Regeneration of DPF
Table 9: Resuits vehicle H6

*Type approval value

hot

TNO reporti TNO 2013 R11891 15December2013

Appendix Al 314

Table 10: Results vehicle E6

Emissions
vehicle E6
.

C02
NOx
THC+NOx
PM
PN

Unit
[mg/k
m]
[g/km]
[mg”k
m]
[mg/k
m]
[mglk
m]
[-/km]

Limit
(Euro
6)

NEDC
cold

NEDC CADC
hot
cold

CADC
hot

WLT
C
cold

WLTC
hot

500

124

4

5

2

x

3

127*

149

131

142

140

x

129

80

98

201

177

175

x

182

170

135

206

180

176

x

183

4.5

0.1

0.0

0.6

0.6

x

0.0

6.OE+1
1

2.9E+0 2.E+0
9
8

2.8E+0
9

1.9E+0
9

X

4.4E+0
8

5.57

4.88

5.31

5.22

x

5.00

Limit
(Euro
6)

NEDC
cold

NEDC CADC
hot
cold

CADC
hot

WLT
C
cold

WLTC
hot

500

372

6

57

20

x

5

119*

127

112

151

149

x

119

80

55

85

447

456

x

205

170

100

99

473

477

x

214

4.5

0.2

0.0

0.1

0.1

x

0.1

6.OE+1
1

4.7E+1
1

3.E+0
9

5.5E+0
7

3.1E-f-0
X
7

4.3E+0
6

4.76

4.17

5.62

5.54

4.45

Fuel
ri,ioo
consumptio
4.9k
km]
n
*Type approval value

Tabie 1 1: Resuits vehicle Ji

Emissions
vehicle JI
.

C02
NOx
THC+NOx
PM
PN

Unit
[mg/k
m]
[g/kmj
[mg/k
m]
[mg/k
m]
[mg/k
m]
[#/km]

Fuel
9/100
4.60*
consumptio
km]
n
*Type approval value

x

TNO report 1 TNO 2013 Ri 1891 1 5 December 2013

Appendix Al 414

Table 12: Resuits Vehicle J2

Emissions
vehicle J2
00
002
NOx
THC+NOx
PM
PN
Fuel
consumpti
0fl

Limit
(Euro
6)

NEDC
cold

NEDC CADC
cold
hot

CADC
hot

WLTC
cold

WLTC
hot

500

661

8

47

7

90

20

119*

127

112

151

150

125

119

80

74

93

716

729

198

247

170

148

113

737

745

217

275

4.5

0.1

0.3

0.3

0.3

0.2

0.1

[#/km]

6.OE+1
1

8.1E+1
0

6.E+0 9.7E+0 3.1E+0 5.2E÷0 5.3E+0
9
7
7
9
6

[1/100
km]

4.60*

4.80

4.17

Unit
[mg/k
m]
[g/km]
[mg/k
m]
[mg/k
m]
[mg/k
m]

*Type approval value

5.64

5.58

4.67

4.45

TNO report 1 TNO 2013 Ri 1891 1 5 December 2013

B

Appendix 8 1117

Determination of emission factors
The national emission factors are the representative emission per kilometre for
different vehicle categories, and different road types and congestion levels. They
are derived from emission measurements, and scaled and weighed to the
representative situation. Current data on Euro 6 diesel vehicles will not be
representative for the Euro 6 vehicle fleet in 2015 or later. The number of makes
and models are very limited. Hence current emission factors for Euro 6 diesel
vehicles are preliminary and they will be adjusted to the future sales distribution of
different technologies.
A second restriction, apart from the representativeness of the current Euro 6
vehicles for the future fleet, is the performance of the emission reduction technology
in real-world circumstances. There is a dear discrepancy between the emissions in
the laboratory and the emissions during the on-road tests, for some vehicles. So
far, the influences of all on-road conditions are not fully understood. For example,
road surface, precipitation, temperature, additional weight, steering, and wind all
affect the engine bad and emissions. Only in part these are characterized during
the trip. However, correcting them to a standard effect for the Dutch situation is only
in its preliminary stages and it will require much more research.
The third restriction to be placed on current results is the apparent “incidental
emissions”. With limited emission control the NO and, in a lesser extent, CO are
proportional to the fuel consumption and C0
2 emission. Traditionally, the limited HC
emissions only occurred at sudden drops in the engine loads, e.g., braking, and
high boads, eg. long periods of accelerations. With the introduction of advanced
emission control, such as LNT for Euro 6, NO emissions occur in batches. A
repetition of the same test will not yield the same emission result as an emission
burst or batch may not occur. A proper functioning LNT will yield such batches but
with very little NO emission. See Figure 22.

TNO report 1 TNO 2013 Ri 1891 1 5 December 2013

254()

2545

2550

2555

Appendix B 1 217

2560
time [secl

2565

2570

2575

2580

Figure 22: Typical regeneration moments at high velocities. A peak of CO and HC with limited
NO emissions.

The LNT NOx emission control is not always as successful as show in Figure 22.
Another case under similar circumstances, ie., motorway driving shows a
succession of regenerations which keeps the average NO emission around 0.5
g/km. See Figure 23.
The normal regeneration of the LNT is not a problem for the emissions. However,
with different vehicles with LNT and several hours of test data, higher emissions
occasionally occur. In some case the LNT fails to regenerate altogether yielding,
eventually high engine-out values for the NO emissions. See Figure 24.

TNO reportTNO 2013 R11891

5December2013

Appendix B 1 317

0
t:,)

E
G)
to
0
0
0

E
0)

time [seci

Figure 23:

LNT emission control during motorway driving yielding a fast succession of
regenerations with still substantial NOemissions.

1000

1100

1200

time [sec]

Figure 24

During rural driving NO emissions may grow occasionally due the delayed or failed
regeneration of the trap.

TNO report 1 TNO 2013 R1 1891

5 December 2013

Appendix B 1 417

More traditional technology, such as EGR, yield not only higher emissions but also
more constant emissions. The emissions is expected to grow with the C0
2
emission.
In principle there are three types of failures of NO emission control: SCR fails 1f the
exhaust-gas temperature is too low, which is at the start and in urban driving with a
lot of idling. The LNT fails when engine out emissions increase without the
possibility to regenerate. This seems most common in high dynamic rural driving.
The last technology EGR has the highest NO emissions at high bad. High bad
typically corresponds with motorway driving. In the last case the NOemissions
increases by all standards: glkm, g/hr, and g/kg C0
. Depending on the technobogy,
2
the derived emission factors follow a certain pattern. LNT can achieve very low NO
emission factors on the motorway, compared with urban and rural emissions. The
same holds for SCR.
Given the variations of the result with technology and with tests the emission factors
are determined from the average of the real-world chassis dynamometer tests. The
results are given in Table 13.
Table 13:

[mglkm]

Emission factors for Euro 6 based on the average of the tests

emission factors

NOx

CD

HC

N02

[mg/km]
urban

Congested

234

79

54

47

Normal

147

46

32

29

free-flow

163

60

38

30

rural

Normal

128

57

30

22

motorway

Average

164

104

33

41

Congested

199

73

42

45

8Okm/h

104

86

33

26

100 km/h control

137

97

29

35

100 km/h

150

100

31

37

120 km/h

189

110

36

43

130 km/h

215

116

38

47

The current emission factors are only a first estimate based on the test results.
There is a substantial risk the emission will be much higher. Both the spread, ie.
standard deviation, of the results as the difference between maximal value and the
mean are an indication for the values that may occur. We define risk as the average
of the standard deviation and the maximal value:
Risk [%] = 1/ (stdev[%] + maximal deviation [%])
Using the highest value only for the risk will be overly conservative, with very worst
case assumptions. Using the standard deviation only will yield a result dominated
by the make-up of the current test program, ie., the availability and selection of
vehicbes. Combining both worst case assumptions yield a robust result incorporating
both the spread and the extremes.

TNO report TNO 2013 R11891 15December2013

Appendix

1 517

We find the risk for urban and rural emission to be around 120% extra emissions,
for motorway the risk is much higher: the additional emissions are around 300%,
yielding up to 0.72 glkm NO emissions are possible for Euro 6 diesel vehicles.
Table 14:

The esbmate of the worst case emission factors for Euro 6 based on the spread in the

results per test.
[mg/km]

emission risk

NOx

N02

urban

Congested

523

190

Normal

326

114

free-flow

342

108

rural

Normal

275

83

motorway

Average

686

218

Congested

554

219

8Okm/h

416

126

100 km/h control

637

209

100 km/h

639

209

120 kmfh

684
720

220

130 km/h

229

These worst case emission factors are confirmed by the PEMS resuits. There are
only two vehicles tested, but the average emission factors from these two Euro 6
cars yields emission factors close to the current Euro 5 emission factors.
Furthermore, the emissions on-road of one vehicle are apparently larger than under
similar circumstances on the chassis dynamometer in the laboratory.
The initial estimates of the emission factors, must be conservative, as the
underlying data is limited. The estimate is based on the following analysis of
emission factors based on the individual tests:
EFestimate = EFaverage + 0.25*STDEV + 0.25* (EFmaxEFaverage)
The experience from Euro 5 would lead to worst case emission factors, as there no
discernible overall reduction from Euro 4 to Euro 5. The worst case emission factors
follow the same trend from Euro 4 onwards. On the other hand, the lowest
emissions, on the official, NEDC tests and also in real-world tests (CADC, WLTC),
have gone down. Also with Euro 5 there was only one vehicle which performed in
real-world tests comparable with the emission limit. With Euro 6 more brands and
models show emissions which follow, in part, the trend of the emission limits.
Hence, for the 2014 Dutch national emission factors a conservative estimate will be
slightly lower than the worst-case risk. The emission factors are therefore set
halfway between the average results and the risk results. The emission factors are
given in Table 15. As can be seen the motorway emission factors are much higher
above the average emission factors, due to the high risk associated with EGR
technology, which is less likely to function in real-world conditions.
The emission factors are in line with the preliminary results of TUG for HBEFA 3.2.
The reduction from Euro 5 to Euro 6 is slightly smaller in the proposed TNO
emission factors than in the HBEFA emission factors. The difference is explained by
three main differences between Dutch emission factors and HBEFA emission

TNO reportl TNO 2013 R11891 15December2013

Appendix BI 617

factors. First, the driving behaviour is different. In the Netherlands the congestion is
typically high and speed limits on the motorway are strict. Second, the compact,
fuel-efficient cars dominate the sales in The Netherlands. The Dutch diesel
passenger car fleet is different from other European countries. Third, particular
choices in testing and modelling are different from other approaches. The Dutch
emission factors are part of the calibrated air-quality model. The approach is kept
as much the same as possible to allow for historical comparison, retain the
calibration, and allow for trend analyses.
Table 15:

Euro 6 diesel emission factors, proposed for the 2014 Dutch national air-quality model.

[mglkm]

emission estimate

NOx

N02

urban

congested

379

119

Normal

237

71

free-flow

252

69

rural

Normal

202

53

motorway

Average
congested

425

129

377

132

80 km/h

260

76

100 km/h control

387

122

100 km/h

394

123

120 km/h

437

131

130 km/h

468

138

The current emission factors are in line with the common strategy to estimate
emission factors based on the ratio between emission limits and measurement data
from earlier Euro-classes. In this case Euro 5. The reduction of the NO emission
limits from Euro 5 to Euro 6 is from 180 mg/km to 80 mg/km. Applying the same
reduction on the Euro 5 emission factors, for which more than sufficient evidence
exists yields extrapolated Euro 6 emission factors which are slightly higher (up to
25%) than the current factors in the urban situations, and lower (down 40%) in the
case of motorway driving:
Table 16:

The Euro 6 emission factors based on the reduction of real-world emissions
proportional to the reduction of the emission limit

[mglkm]
urban

Euro 5 extrapolation
congested

NOx

N02

476

148

normal

281

86

free-flow

257

77

rural

normal

153

45

motorway

average

269

87

congested

447

149

80 km/h

186

61

100 km/h control

228

74

100 km/h
120 km/h

234

75

258

80

130 km/h

272

83

TNO reporti TNO 2013 R11891 15December2013

Appendix BI 7/7

The overview of the tables is shown in Figure 25. The larger the spread in the data
the larger the risk. The actual emission factors are set halfway between the risk and
the average value.

1000

•
-

800

Emission factors based on single test
average value of all tests
emission factors estimate
risk

-

(1)

600

-

o
400

E

0)

0

z 200

z

0.

urban
Figure 25:

rural

motorway

visualization of the emission factors in the different tables. The spread in motorway
emission is large, yielding a substantial risk for high emissions, comparable to Euro 5.