Particulate Control Experience with GDI and GPFs

Dr. Rasto Brezny

Manufacturers of Emission Controls Association www.meca.org

September 28, 2016 South Coast AQMD

Diamond Bar, CA

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MECA Technologies Control Criteria and GHG Emission

Air Handling

Exhaust System Integration

OBD Sensors Waste Heat Recovery

Powertrain Electrification

Evaporative Controls

Filters & Substrates

Fuel Combustion Controls

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LEV III/Tier 3 Phase-In PN Implemented Soon for GDI Vehicles

0.0000.0100.0200.0300.0400.0500.0600.0700.0800.0900.1000.1100.120

'15 '16 '17 '18 '19 '20 '21 '22 '23 '24 '25

FTP NMOG+NOx LEV III Emissions, g/mi

PCs

0.030 NMOG+NOx (SULEV or Tier 2, Bin 2)

LDT2s

3 mg/mi PM phase-in

2017- 2021

1 mg/mi LEV III PM phase-in 2025-2028

LEV III Start

ARB PM Review

Euro 6c GDI PN limit (6 X 1011/km)

China PN limit (6 X 1011/km) India PN limit (6 X 1012/km)

India PN limit (6 X 1011/km)

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Understanding GDI PM Emissions • GDI fleet is growing; expected to reach 7 million per year by 2020 in U.S. • MECA has been studying GDI PM characteristics and GPF performance for

past 5 years. – PM/PN emissions are highest during cold start, transient and sub-

ambient temps – Vehicle cold-start strategy introduces PM variability – Fuel chemistry can affect GDI PM through PM Index – Lean GDI combustion exhibits range of EC and OC – Secondary organic aerosol emissions from GDI engines

• GPFs reduce variability in PM emissions caused by fuel, temperature and driving effects to lowest possible levels.

• Advanced fuel injection systems are delivering PM levels well below 1 mg/mile

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Engine and Injection Technology Impacts Particulate Emissions

FTP UC

Federal Test Procedure Unified Cycle

WG-DI SG-DI PFI FFV

Wall guided direct injection Spay guided direct injection Port fuel injected Flex fuel vehicle

CE-CERT, Karavalakis et al., ES&T, 2014

Ericsson, 2010

GDI PM Resembles Diesel PM

40 nm

9 nm

200 nm

GDI soot

100 nm

Diesel soot

ORNL, 2014

6 Source: CE-CERT, Karavalakis 2016

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Source : Anforderungen an Partikelfiltersysteme für Dieselmotoren, A.Mayer, TTM

Anatomy of a Wall-flow Particulate Filter

Engine Out

Emissions Alternately Open / Plugged Channels

Porous Ceramic Wall

Tailpipe Emissions

Soot Particles

• Effectively reduce: >95% PM, >99% UFP reduction

• Catalyzed filters capture and incinerate soot and associated toxics

• Experience with tens of millions of OE applications

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GPFs Designed to Minimize Back Pressure

HKIPT Conf, 10/15 8

• Thinner wall high porosity substrates optimized for back pressure and fuel economy

• Porosity allows higher catalyst loadings and lower thermal mass

• Higher cell density provide higher geometric surface area

• Ford SAE paper 2016-01-0941 concluded no impact on fuel economy from GPF after 150K miles.

GPF Effectively Reduces GDI Particle Emissions – MECA/Environment Canada Test Program

• GDI shows higher particle number emissions than PFI • Highest PM emissions during cold-start and acceleration • GPF efficiencies of around 85% • GPF regeneration under US06 • E10 vs. E0 – relatively small effects at normal ambient temps. • Both PFI and GDI emit ultrafine particles below 23 nm

SAE 2012-01-1727

Source: Environment Canada, 2016 9

-93% -96%

GPF Effectively Reduces Ultrafine Metal Oxide Ash Particulates

Met

al o

xide

em

issi

ons,

μg/

mi

US06

E0 E10

Met

al o

xide

em

issi

ons,

μg/

mi

FTP-75

E0

-80%

• Metal oxide ash particles have been shown to exhibited high oxidative stress response • These ultrafine particles are less than 10 nm • High concentrations observed under high-load (US06) • GPF demonstrated high removal efficiency.

Source: Environment Canada, 2012 10

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49% 16% 97% OC Removal

97% 79% > 99% EC Removal

89% 55% > 99% TC Removal

PM from Lean-burn GDI Engine MECA Program at Oak Ridge National Lab

ORNL: SAE 2016-01-0937 11

GPF Durability Demonstrated in Europe

SAE 2015-01-1073

Torque Power

Particle Number NEDC / WLTC / Artemis test cycle Criteria Pollutants

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CO2

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First Commercial GDI/GPF Tested

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RDE Testing of Catalyzed GPF

Euro 6c PN limit

Euro 6c PN limit

http://www.aecc.be/en/Publications/RDE%20PN_Technical_Seminar.html.

CE-CERT GDI Aerosol and PM Characterization

• SCAQMD/MECA program to characterize primary and secondary PM/PN • MECA demonstrating catalyzed GPF technology on two advanced technology vehicles • PM profile is vehicle technology and calibration specific • Study will characterize PAH emissions

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0.00

2.00

4.00

6.00

8.00

10.00

12.00

Accent Accord Soul Impala Mazda3 Mazda3w/ GPF

Carb

onac

eous

Aer

osol

(mg/

mile

) BC POA SOA

Source: CE-CERT, Karavalakis, 2016

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• GDI response time is longer than diesel • Stoichiometric operation poses challenges for sensor regeneration • Correlating PN and PM between vehicles

Electrode / Heater

Exhaust

Accumulator sensor

Electrostatic Sensor

Resistance

OBD Sensor Technology Being Developed for GPFs

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Summary and Conclusions • Vehicle combustion strategy, fuel and calibration affects PM and PN emissions.

• ARB has concluded that 1 mg/mile PM can be measured using existing test methods

• Fuel Injection and filter technologies demonstrated ability to meet EU PN standard and LEV III 1 mg/mile standard

• GPFs have demonstrated no measurable fuel economy impacts. First commercial introduction in 2015, more in 2017.

• Several OEMs have announced broad deployment of GPFs on tens of millions of vehicles by 2022 in Europe.

• Particle number regulations in Europe, India and China will demand best available technologies in 2017-2023 timeframe.

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