particle emissions from vehicles : feedback of road transport...oct 01, 2014 · 2013 -elles 3...

Renewable energies | Eco-friendly production | Innovative transport | Eco-efficient processes | Sustainable resources

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Forum AE – WP3 1st Meeting 10/01/2014 - Manchester

Ludovic Noël

Research engineer , Fuel, Emissions & Lubricants department

Olivier Colin

Research engineer , Engine CFD & Simulation department

Christian Angelberger

Project Leader, Engine CFD & Simulation department

Particle emissions from vehicles : Feedback of road transport

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Forum AE – WP3 1st Meeting 10/01/2014 - Manchester 2

Outline

Context

Evolution of EU emission regulations for road transport

Description of particles emitted by vehicles

Detailed characterization of particles

Solutions to reduce particle emissions

CFD modeling at IFPEN

Conclusions

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Context

Historically, particle emissions have been related

to Diesel vehicles and to road transport

Due to their demonstrated relationship with health

effects, a lot of research studies have been

performed to reduce emissions from Diesel

engines

Comprehension of formation mechanisms

Development of technical solutions

Useful experience to reduce other sources of

particles

Other vehicle technologies

Air transport…

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Context

Air quality standards in Europe aims to reduce population exposure to air

pollutants

PM10, PM2.5, NO2, CO, O3...

The Member States should propose an air quality plan to ensure compliance with the

limit values

Role of transports

Emissions from transport

have been declining since 1990,

but Transport remains an important

source for NOx and PM emissions

In 2010, the daily limit value for PM10

was exceeded at 33 % of traffic sites

across the EU source : European Environment Agency

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Road transport Evolution of PM emission regulations in Europe

Strong reduction of PM emissions

from Diesel engines during the last

20 years

Euro5&6 PM limit = 4,5 mg/km on

NEDC

On Board Diagnostics (OBD) limit for

Euro6 : 12 mg/km

1 “Euro1 new Diesel vehicle” ~ 30

“Euro5” Diesel vehicles for PM

emissions ...

... probably more by taking into

account the ageing of vehicles

(drifting of nominal emissions)

Euro1

1993Euro2

1996Euro3

2000Euro4

2005Euro5

2011Euro6

2014

S1

0

0,05

0,1

0,15

PM

(g

/km

)

Evolution of EU emission regulations for Light Duty vehicles

-96%

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EuroI

1992EuroII

1998EuroIII

2000EuroIV

2005EuroV

2008Euro VI

2013

Steady state testing

Transient Testing0

0,05

0,1

0,15

0,2

0,25

0,3

0,35

0,4

PM

(g

/kW

h)

Evolution of EU emission regulations for Heavy Duty engines

-97%


StageI

1999StageII

2002 StageIIIA

2006StageIIIB

2011StageIV

2014

130-560kW

75-130kW

37-75kW19-37kW

0

0,2

0,4

0,6

0,8

1

PM

(g

/kW

h)

Evolution of EU emission regulations for Non Road engines

-95%

Simultaneously, PM emissions from

new types of heavy duty engines have

been also strongly decreased

Emission durability period extended

(€VI : 700000 km or 7 years for the last

class of vehicles)

From Euro IV, OBD required

Euro VI regulation introduced off-cycle

emissions (OCE) testing requirements

Off-Road Diesel engines

Drilling rigs, Compressors, Bulldozers,

Non-road trucks, Mobile cranes...

Emission standards are following the

same trend as for HD engines

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Health effects related to ultrafine particles have led to further evolution of particle

emission regulations

Ultrafine particles have a low contribution to the total particle mass, but mainly affect

the total particle number

Additionally to the regulation of particle mass, a regulation of particle number has

been introduced (particle size >23nm)

Since 2011 for LD Diesel engines (6.1011 #/km, PMP measurement procedure)

From 2013 for HD Diesel engines

Off-road engines in 2017?

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What about spark ignition (SI) engines ?

Spark Ignition Direct Injection (or

GDI) engines can emit a high

number of fine particles, sometimes

higher than Diesel equipped with

DPF

A PN emission limit for GDI vehicles has

been defined in 2 steps

6.1012 #/km from 2014

6.1011 #/km (= Diesel limit) from 2017

Towards a “fuel neutral” regulation for

particle emissions

Euro6 PN limit

source : J.Anderson et al., 2007

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Comparison of LD vehicle technologies NEDC cycle

Using a particle filter on Diesel engine leads to

a strong reduction of both particle mass and

particle number (PMP procedure)

Typical values for particle concentration are

around 1E5 #/cm3

The GDI vehicle does not comply with future

Euro6b standards for particle number

source : IFP Energies nouvelles, 2010

0

5

10

15

20

25

30

35

Diesel Euro3 Diesel + DPF Euro4 GDI Euro5

Part

icle

mass (

mg

/km

)

New European Driving Cycle (NEDC)

Euro 6 limit : 4.5mg/km

1.00E+09

1.00E+10

1.00E+11

1.00E+12

1.00E+13

1.00E+14

Diesel Euro3 Diesel + DPF Euro4 GDI Euro5

Pa

rtic

le n

um

be

r (#

/km

)

NEDC froid

Euro 6b limit (2017) : 6E11 #/km

Euro 6a limit (2014) : 6E12 #/km

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Particle emissions from vehicles From primary particles to PM 1, 2.5, 10

Primary particle (1nm-30nm) : Black

Carbon or Soot, +metals, ash ...

Aggregates of primary particles and

soluble species (50nm-1µm)

Soluble Organic Fraction : condensed

HC (PAH, Oxygenated...), Sulfates and

Water

source : Johnson et al., 1994

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Particle emissions from vehicles From primary particles to PM 1, 2.5, 10

The size distribution of particles

emitted by internal combustion

engine is bimodal

Nucleation mode (10-30nm) : poor

contribution to the total mass, but up

to 90% of the total number

Accumulation mode (50nm-1µm) :

High contribution to the total mass

Soot aggregates emitted by engines

and vehicles undergo chemical and

physical transformations into the

atmosphere and contribute to PM1,

PM2,5 or PM10 global

concentrations

source : D.B.Kittelson., 1998

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Detailed characterization

The strong evolution of emission

regulations requires a detailed

characterization of physical and

chemical properties of particles

The morphology can be analyzed

using electronic microscopy (SEM

and TEM)

Chemical analysis of the soluble

organic fraction can be performed

using High Performance Liquid

Chromatography (HPLC) :

Identification of 15 polycyclic

aromatic hydrocarbons (PAH)

specified by the Environment

Protection Agency (EPA)

GC-MS, Raman Spectroscopy …


Diesel engine GDI engine

NEDC


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Soot Formation in Diesel engines

Combustion in Diesel engines is fully

heterogeneous Fuel and air are non

premixed before combustion

Strong heterogeneities of temperature and

local equivalence ratio (~fuel/air ratio)

Soot is formed into the flame between 1500

and 2000 K for rich conditions

Advanced combustion concepts allow

reducing both soot and NOx formation

High injection pressure (> 2000 bars)

Low Temperature Combustion (LTC)

Homogeneous Combustion (HCCI)

...

source : J.E.Dec., 2009

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Identification of reduction solutions Engine technology

Fuel injection system

Direct injection

High injection pressure

Multiple injections

Injector design (nozzle, holes...)

Air management

Intake manifolds

in-cylinder aerodynamics

Combustion chamber

Piston geometry

Variable Valve Actuation

Compression Ratio

Low Temperature Combustion

Electronic control ...

source : auto-innovations

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Identification of reduction solutions After treatment

Since Euro5, the low levels of PM limit requires

the use of after treatment devices, i.e. Diesel

Particle Filter (DPF) for LD vehicles

Reduction of 95-99.9% for BC,

‘’ ‘’ ‘’ 70-95% for total PM

Reduction of PN by 2 orders of magnitude

source : Andersson et al., 2001


1,0E+03

1,0E+04

1,0E+05

1,0E+06

1,0E+07

1,0E+08

1,0E+09

1 10 100 1000

Dp (nm)

No

rmal

ize

d C

on

cen

trat

ion

dN

/dLo

dD

p (

#/cm

3)

Without DPF

With DPF

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Identification of reduction solutions Alternative fuels

Additionally to engine technology and after treatment devices, properties of

alternative fuels can be used to enhance PM reduction (mass and/or number)

Volatility Evaporation process and mixture formation

Aromatic compounds PAH = soot precursors

Sulfur level Effect on nucleation process

Oxygenated alternative fuels

Fatty Acid Methyl Esters (FAME) for Diesel engines or Ethanol for SI engines

Paraffinic alternative fuels

High cetane number, near zero aromatic content, sulfur free

Hydrotreated vegetable Oils (HVO)

Synthetic fuels obtained by Fisher Tropsch Process (i.e. “XtL” fuels : Gas to Liquid

(GtL), Coal to Liquid (CtL), Biomass to Liquid (BtL))

Natural Gas

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Effects of fuel properties (GDI engine)

A reference ethanol-free gasoline has been compared to an E10 fuel (containing

10 % ethanol) and to an alkylate synthetic fuel mainly blended from paraffinic

compounds

The results show that the alkylate fuel leads to a strong reduction of particle

concentrations and to the diminution of the particle mean diameter compared to E0 and

E10


Pinj=80bar, nominal SOI

0E+00

1E+06

2E+06

3E+06

4E+06

5E+06

6E+06

7E+06

1 10 100 1000

Dp (nm)

No

rma

lize

d c

on

ce

ntr

ati

on

dN

/dL

og

Dp

(#

/cm

3)

E0E10Alkylate

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Soot formation models for Diesel applications have been developed for many

years

New chalenges for industrial applications require an evolution of CFD modeling

Model for particle size and number => sectional soot model (SSM)

Wide range of thermodynamic conditions

Effect of fuel composition (biofuels) => need for detailled chemistry in the

model => tabulated chemistry

Modelling strategy employed

SSM based on [1,2]

Coupling of SSM with the tabulated Diesel combustion model VPTHC [3]

Modeling : A major issue to reduce particle emissions

[2] Vervisch-Kljakic P., PhD thesis, IFPEN, 2012

[3] Michel J-B, Colin O., Int. Journal of Eng. Research, 2013

[1] Netzell K. et al., P. Comb. Inst., 2007

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Experimental setup

Single cylinder Diesel engine (500cc)

Particle size distribution measured with DMS 500

Commercial Diesel fuel and surrogate fuel (70% n-decane / 30% alpha-

methylnaphtalene) : good match in terms of soot emissions

Color Red Green Bleue

Rpm 2200 2200 4000

PMI [bar] 8 8 20

Fref 0,45 0,45 0,85

Variation Pinj EGR Richesse

(tinj)

CFD modeling Evaluation on an Diesel engine Database

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RANS simulations

IFP-C3D code

Combustion: VPTHC

Soot: SSM

Surrogate chemistry from Reaction

Design consortium (590 species, 3894

reactions)

Quantitative agreement for a majority

of points with SSM

Peak position and width of SNDF is

correctly recovered

Mass flow rate

CFD modeling RANS Simulations

Size distribution

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Soot size distribution averaged over the combustion

chamber. Reference case at 4000 rpm

Reference case at 4000rpm

time= 30 CAD ATDC

Fuel/air ratio (up left)

Temperature (up right)

Soot mass fraction in

sections:

1nm (down left)

20nm (down right)

CFD modeling Space and time evolutions

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Conclusions

The knowledge from road transport and Diesel particles can be useful to reduce

particle emissions from other sources

Comprehension of formation mechanisms

Measurement procedures, Analysis

Reduction pathways

Particle emissions emitted by road transport have been strongly reduced during

the last 20 years

Reduction of the particle mass by a factor of ~30

Limitation of ultrafine particles (particle number)

The combination of different technical solutions allowed reducing particle

emissions from road transport

Optimization of the combustion process

Development of alternative fuels

After treatment devices

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Conclusions

Research activities are now focusing on the characterization of ultrafine particles

emitted by vehicles

Comprehension of the formation mechanisms of soot particles in SI engines

Impact of DPF regeneration processes on the emission of ultrafine particles

Improvement of prediction models ASMAPE project : Advanced Soot Model for Aeronautics and Piston Engines (IFPEN, SNECMA, PSA, CORIA,

CNRS)

Requirement of an accurate characterization of the nature of nanoparticles (<50nm)

from combustion processes

Chemical composition

Morphology

Identification of sources and comprehension of evolution process

Remaining questions

What is the relationship between ultrafine particles emitted by vehicles (0-100nm) and

PM10 ? Evolution of atmospheric aerosols


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Photofuels – 1st Meeting 11&12 /09/2013 - Braunschweig

www.ifpenergiesnouvelles.com


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As part of the public-interest mission with which it has been tasked by the public authorities, IFPEN focuses on:

- providing solutions to take up the challenges facing society in terms of energy and the climate, promoting the emergence of a sustainable energy mix

- creating wealth and jobs by supporting French and European economic activity, and the competitiveness of related industrial sectors

IFPEN

IFPEN is a public research and training player

It has an international scope, covering the fields of energy, transport and the environment

From research to industry, technological innovation is central to all its activities

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At a glance

1,675 people*, including 1,146

researchers (engineers and

technicians), based in Rueil-

Malmaison and Lyon

123 doctoral and 10 post-doctoral

researchers

More than 50 professions

represented: from geological

engineers to powertrain engineers

A very high-quality technical

environment (testing resources,

equipment, supercalculator with a

power of 110 Teraflops)

Status: state-owned industrial and

commercial establishment (EPIC)

Funding: state budget and resources

provided by private French and foreign

partners

Budget for 2012: €303.4 million,

including €245.8 million for R&D

In 2012:

12,200 active patents

More than 200 articles published in

international scientific journals

* mean workforce, full-time equivalent

IFPEN

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5

INNOVATIVE

TRANSPORT

ECO-FRIENDLY

PRODUCTION

RENEWABLE

ENERGIES

SUSTAINABLE

RESOURCES

ECO-EFFICIENT

PROCESSES

ENERGY EFFICIENCYREDUCING THE

ECOLOGICAL IMPACT

CLIMATE CHANGE: CUTTING CO2 EMISSIONS

DECARBONATION

SECURING

SUPPLIES

SUSTAINABLE DEVELOPMENT

ENERGY

DIVERSIFICATION

Producing

fuels, chemical

intermediates

and energy

from renewable

sources

Producing energy

while mitigating

the environmental

footprint

Developing

fuel-efficient,

environmentally-

friendly transport

Producing

environmentally-

friendly fuels and

chemical

intermediates

from fossil

resources

Providing

environmentally-

friendly

technologies and

pushing back

the current

boundaries of oil

and gas reserves

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5 complementary strategic priorities

particle emissions from vehicles : feedback of road transport...oct 01, 2014 · 2013 -elles 3...

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