particulate control experience with gdi and gpfs · pdf file28.09.2016 ·...
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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
3
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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