Approaches to Quantifying Heavy-Duty In-Use Vehicles Emissions in California

Shaohua Hu, Ph.D. P.E.Measurement Assessment and Research Section, Monitoring

and Laboratory Division

Current HDE Emissions Standards NOx reduced 97%HC reduced 89 % PM reduced 98%

NOx 6.0 g/bhp-hr

HC 0.14 g/bhp-hrNOx 0.2 g/bhp-hr

PM 0.01 g/bhp-hr

HC 1.3 g/bhp-hr

PM 0.6 g/bhp-hr

1987

present

Heavy-Duty Engine Emissions Standards

1

Ecosystem of Vehicle Testing

2

Mobile Sources

Laboratory Dynamometer

TestingEngine and

chassis dynamometer

testing

On-Board Diagnostic Tools Collect ECU and Emissions data

On-Road Emissions

MeasurementsPortable

Emissions Measurement

Systems (PEMS)

Roadside and Remote Sensing Measurements

Plume entrainment or remote imaging

systems

HD On-road PEMS

PEAQS

HD OBD

MTA Engine DynoMTA Chassis Dyno

Depot Park Chassis Dyno

Off-road PEMS

LD On-road PEMS

Instrument Trailer

Updraft Exhaust Intake

Downdraft Exhaust Intake

Heavy-Duty In-Use Vehicle Testing Capabilities

3

What is Remote Sensing?• “Remote” emissions measurement

• Emissions measured without touching the vehicle using a Remote Sensing Device (RSD)

• Utilizes emitted radiation to collect emission measurements• Infrared Radiation - Denver University (DU) FEATS• Laser (or LiDAR) – H.E.A.T EDAR, Satellite measurements

• Plume Capture• Similar data, but exhaust plume is physically sampled• DU Tent Measurements, PEAQS, UC Berkeley

4

What is PEAQS?

https://www.youtube.com/watch?v=5kdsRR7_VVE

The Portable Emission Acquisition System, or PEAQS, is a roadside emission measurement system that captures a portion of a passing vehicle’s exhaust as it drives through to determine an emission snapshot in real-time.§ Screening tool to help target enforcement activities § Aid in community air quality monitoring

CARB PEAQS

ALPR

Instrument Trailer

Downdraft exhaust intake

Updraft exhaust intake

• Design criteria:üReal-time measurements built-in QA/QCüPortableüCharacterize vehicle speed and accelerationüPlug and play operationüExplore low-cost technologyüAbility to scale up

5

PEAQS Components

6

Additional Inspection

Species InstrumentCO2 Licor-820/840

BCMagee AE-33

AethLabs AE-51

NOXCAI CLD-64

EcoPhysics CLD-844

OtherGeovision Camera

Doppler Radar, Lidar

PEAQS Front-EndCO

2N

OxBC

Captured Truck Exhaust PlumesNo Measurable BC or NOX

Vehicle ImageMost Recent Valid

EFBCEF g$ kg&'() *+ = ∫.

/ P1 − P. 34∫./ CO7/ − CO7. 34

×9: 7

PEAQS Versions

‘Mid-Grade System’

‘Laboratory Grade System’Instrumentation In Trailer

8

PEAQS Field Deployments• PEAQS deployed at 6 locations

across California• >10,000 valid vehicular plumes

measured

• California Department of Food and Agriculture, Truckee

• Port of Oakland• Stockton, CA Intermodal

Railyards• Port of Los Angeles• Cottonwood- California Highway

Patrol Weigh Station• Caldecott Tunnel – Oakland, CA

9

PEAQS In the Field

Truckee, CA: California Department of Food & Agriculture (CDFA) Truckee

Wilmington, CA: Port of Los Angeles

PEAQS has measured> 10,000 vehicles

10

Roadside

Inside Facility

PEAQS Results

• Above values are for all valid plume captures during all sampling conducted at each location

• POLA includes information from December 2016 and April 2017

All units in g / kg fuelAverage Median

AE-51 BC AE-33 BC NOX AE-51 BC AE-33 BC NOXCDFA Truckee 0.18 0.26 20.2 0.02 0.12 4.51

COTTONWOOD 0.04 0.05 6.6 0.004 0.01 2.20

POLA 0.04 0.03 7.2 0.01 0.01 2.13

Port of Oakland 0.03 0.06 11.3 0.01 0.03 9.47

11

Emissions Trend: Black Carbon

2001 2008 2010 2012 2014

0.0

0.5

1.0

1.5

2.0

2.5

3.0

Port of Los Angeles April 2017

Chassis MYBC

EF

(gBC

/kg

fuel

)

• Lower average BC emissions at Port of Los Angeles relative to Cottonwood Weigh Station• Majority of vehicles measured had BC < detection limit (total n >1,000 at each site)• BC emissions driven by ‘high emitters’

1989 1999 2003 2007 2011 2015

0.0

0.5

1.0

1.5

2.0

2.5

3.0

Cottonwood CHP Station April 2017

Chassis MY

BC E

F (g

BC/k

g fu

el)

n = 142

n = 90

12

Emissions Trend: Nitrogen Oxides

1985 1998 2002 2006 2010 2014

020

4060

8010

012

0

Cottonwood CHP Station April 2017

Chassis MY

NO

x EF

(gN

Ox/

kg fu

el)

• Broader model year distribution at Cottonwood • NOX emissions decrease with MY 2010+ MY• NOX emission averages driven by ‘high emitters’

2001 2006 2009 2011 2013 2015

020

4060

8010

012

0

Port of Los Angeles April 2017

Chassis MYN

Ox

EF (g

NO

x/kg

fuel

)n = 368

n = 321

13

PEAQS Application: “Highest Emitter” Identification

Data collected by PEAQS during 2016-2017 14

Build-in library to dynamically update with emissions data to determine top percentile

BC NOX

High Emitting Vehicle Determinations

• Fuel-based emission factors corresponding to possible exceedances of emission standards as a function of vehicle power.

• A typical HD vehicle (~ 65,000 lbs) will have exceeded the model year (MY) 2010 emission standards (of 0.2 g NOx/bhp-hrand 0.01 g PM/bhp-hr) by three times when fuel-based emission factors are 9.3 g NOx/kg fuel and 0.11 g PM/kg fuel when measured using the roadside plume measurement approach.

Quiros, D., Smith, J., Ham, W., Robertson, W., Huai, T., Ayala A. & Hu, S. (2018) Deriving fuel-based emission factor thresholds to interpret heavy-duty vehicle roadside plume measurements, Journal of the Air & Waste Management Association, 68:9, 969-987, DOI: 10.1080/10962247.2018.1460637

15

Please note, those threshold values depend on vehicle driving activities.

A Side Successful Story of PEAQSDuring the November 2016 filed campaign, PEAQS helped to ‘identify’ Glider Kits

a. SAE J1667b. g NOX/ kg fuel on arrival (< 1 mph, decelerating)c. g NOX / kg fuel as vehicle departed

a Snap Idle Driving Through

Opacity BC BC b NOX,i c NOX,f% g/kg fuel g/kg fuel

Glider Kit 1 11.5 0.84 0.025 0.01 1.37

Glider Kit 2 89.3 60 0.21 27.7 39.6

16

RSD Data Application: “Hot-Sheets”• Create database of measured ‘high-emitters’

• Top 5-10% of the fleet • “Hot-sheet” created and distributed to Mobile Enforcement as targets for further inspection

• License Plate and vehicle description• Fast screening of vehicles at Ports of Entry – CHP Weigh Stations, Agricultural Inspection Stations,

etc.

Vehicle passes

RSD

Data uploaded

into Statewide Database

BC/NOXEmissions found to be in top

5%

Vehicle added to Monthly

‘Hot-Sheet’

Vehicle found at

weigh station

and pulled for

inspection

Maintenancerelated

emissions failure

Manufacturerrelated

emissions failure

17

Summary and Next Steps

18

• PEAQS is an important emissions measurement toolo Provide a large quantity of data in a cost-

effective wayo Identify “high emitting” vehicles through roadside

plume captureo Provide emissions trends

• Next step is to expand measurement to multiple locations across CA through small, lower cost applicationso Get PEAQS out on roadways across CA to

10 locationso Create emissions database structure and

procedure for fast data communication

Questions?

19

Ecosystem of Vehicle Testing

20

Mobile Sources

Laboratory Dynamometer

TestingEngine and

chassis dynamometer

testing

On-Board Diagnostic Tools Collect ECU and Emissions data

On-Road Emissions

MeasurementsPortable

Emissions Measurement

Systems (PEMS)

Roadside and Remote Sensing Measurements

Plume entrainment or remote imaging

systems

• Sales volume used to select initial MY 2010 and newer engine families for pilot

• Class 4 through 8 vehicles tested at 80% of GVWR (GVWR ranges 14,000-80,000 lbs)

Design of California’s Pioneering Pilot Truck and Bus Surveillance Program

• ‘Randomly’ recruited from state population from small and large fleets with lower (<100,000 mi) to higher (>435,000 mi) odometer readings

• Chassis dynamometer and PEMS testing for 2-3 weeks

• Launched April 2016, will run about two (2) years, 40+ vehicles to date

Key Events for Recruiting, Procuring & Testing

Recruitment & Procurement

Check-In Procedure

• Fuel sample

• Photo documentation

• Oil sample

• DEF check

• Opacity test

• Under-hood inspection

• OBD scan

• Coast-down (for unusual body types)

Check-Out Procedure

• Opacity test

• OBD scan

• Truck wash

• Truck re-fuel

• DEF refill

Return to Fleet

• Transport from Sacramento laboratory back to fleet

• Check issued to fleet by ARB contractor

• Identify vehicle from on-road fleet

• Collect maintenance history

• Sign rental agreement

• Transport from fleet to Sacramento laboratory

Laboratory Testing on Chassis Dynamometer

• Six cycles 20-55 min, 1.8-62 mph avg speed

• 1-hour idling tests under three loads

• 5-15 minute preconditioning specific to each cycle to achieve “hot-start” conditions

• Raw exhaust gas (AVL AMA i60 bench), multi-gas FTIR, partial-flow PM (Sierra Instruments BG-3), and pitot-tube exhaust flow (EFM-HS, Sensors)

• Active OBD monitoring using CANalyzer (Vector Software GmbH)

• As needed, confirmatory on-road testing using PEMS

Program web site: https://www.arb.ca.gov/msprog/onroad/tbsp/tbsp.htm

3 to 5 days 2 to 3 days 4 to 7 days (more if PEMS testing) 1 day 1 day

Test Vehicle Matrix

* 15-L HHD diesel engines manufactured by Cummins with similar performance and NOx certification levels.** This engine family uses an engine shutdown system (ESS) and is not Clean Idle Certified (<30 g/hr).

A 2010 Cummins MHD Diesel 6.7 0.17B* 2010 Cummins HHD Diesel 14.9 0.25 #1C 2010 Detroit Diesel HHD Diesel 14.8 0.15 #1,3D 2011 Ford HDO Gas 6.8 0.05 #1,2,3E 2011 Cummins UB CNG 8.9 0.13 #1,2,3F* 2011 Cummins HHD Diesel 14.9 0.24G 2012 Ford LHD Diesel 6.7 0.12 #1,2,3H 2012 Navistar MHD Diesel 7.6 0.3 #1,2,3I* 2012 Cummins HHD Diesel 14.9 0.24 #1,2J 2013 Isuzu LHD Diesel 5.2 0.16 #2,3K 2013 Paccar HHD Diesel 12.9 0.12L* 2013 Cummins HHD Diesel 14.9 0.18M 2014 Volvo HHD Diesel 12.8 0.06 #3N 2014 Detroit Diesel HHD Diesel 14.8 0.09

O* 2014 Cummins HHD Diesel 14.9 0.18

P 2014 Navistar HHD Diesel 12.4 0.12 #2,3

Fuel Disp (L) Cert NOx (g/bhp-hr) Test NeedMY Manufacturer Weight Class

Six Cycles Represent Average Speeds From 1.8 to 62 mi/hr (3 to 100 km/hr)

24

Emissions measured include CO, CO2, THC, NOx, PM, opacity following SAE J1667 (40% limit CA), DEF purity check, fuel and lube oil analysis, and real-time PM metrics

List and statistics of test cycles for TBSP

• A wide range of duty cycles that HD trucks may undergo in the real-world, and• Help better understand the relationship between average vehicle speed and emissions to better

strengthen the current speed-correction curves used in the EMFAC emissions model.

Results to Date Confirm PM Emissions from MY 2010+ Diesel Engines are Low

• Random roadside surveys indicate small percentages of vehicles with MY 2010 engines exceed 5% opacity following SAE J1667:Ø In 2011: 2%Ø In 2014: 2%Ø In 2016: 3%

Measured J1667 opacity ranged from 0.00 to 1.43%, and all vehicles had PM emissions (UDDS) >90% below standard*

UDDS

*Tests with active DPF regeneration excluded from bar chart

UDDS Brake-SpecificNOx (18.9 mph)

• UDDS is used as base emissions rate in EMFAC

• At 65,000 lbs, UDDS and engine FTP power close for many engine platforms

• Engine families already referred to full HD In-Use Compliance (HDIUC) Program

SCR Conversion Efficiency

28

29

• DP-WSAC ART: Arterial driving, combined with highway speeds • DP-WSAC INDEXT with extended industrial: Low speed allows SCR temperature to drop• DP-PLAC: Uphill and heavy loads

TBSP PEMS NTE Events

30

Can you use OBD data to calculate NOX emission rates?

• If we have accurate exhaust mass air flow and NOX-out concentrations, we should be able to, right?

31

• Large number of adapters• Most function very similarly• Standalone and computer interface options

OBD Data Collection (Hardware)

32

• Intake mass air flow (PGN 61450 – SPN 132)• Mass flow rate of fresh air entering the engine air intake, before any EGR mixer, if used.

Flow rate of fresh air conducted to the engine cylinders to support combustion.

• Engine Total Intake Mass Air Flow Rate (PGN 61497 – SPN 6396)• Mass Flow rate of air entering the engine. This also includes the amount of exhaust gas

recirculated, if any.

• Engine Exhaust Flow Rate (PGN 64587 – SPN 6895)• Engine Exhaust Flow Rate shall indicate the measured/calculated exhaust gas mass flow

upstream of the aftertreatment system.

• Aftertreatment 1 gas mass flow (PGN 65247 – SPN 3236)• Measured/calculated exhaust gas mass upstream of the aftertreatment system in

exhaust bank 1 and 2.

Mass Flow – what should we use?

33

• DPA5_Aftertreatment 1 Outlet NOx 1_ppm• The amount of combined NO and NO2 in the exhaust exiting the aftertreatment system

measured by a NOx sensor at the aftertreatment outlet, represented in NOx molecule parts per million non-NOx molecules in exhaust bank 1.

• PGN 61455 – SPN 3226

• DPA5_Aftertreatment 1 Outlet NOx 1 Reading Stable_bit• Indicates that the NOx reading of the aftertreatment outlet NOx sensor is stable as

determined by the manufacturer’s control software in exhaust bank 1.• PGN 61455 – SPN 3230

• We only use OBD NOx data when the sensor reading is stable• Handles sleep events and zero/span when sensor comes online

NOX Sensor – what we use

34

Exhaust flow – Using Aftertreatment 1 MAF – DD14

• Most slopes have R2 of 0.9 – 1.1• Poor correlation for cycles with low flowrates (eg idle test)• Uncertainty in measurement or calculation?

35

Sensor went to sleep

• NOX emission rates look very similar when SCR is hot• Near Dock Drayage cycle has extended periods of low SCR temperatures and

idle flowrates. Very poor correlation because the NOX sensor goes to sleep when the SCR is cold and mass air flow estimates have more uncertainty

Combining OBD MAF and NOX

36

• HD chassis dyno• 2 diesel trucks

• same 2014MY engine family

• UDDS & cruise tests• NOx sensor active

time >90%

On-Board NOX Sensor Data vs Lab Bench Measurement

Conclusion• Successes

• 40+ vehicles tested across 20+ engine families• PM emissions lower than standard• In-Use NOx emissions higher than expected• Program provides ‘platform’ for evaluating OBD performance, and tracking other

measures for further program development• OBD NOx data vs Lab NOx data in good agreement for >90% completeness

• Challenges• Vehicle procurement• Vehicle condition• Consistency with OBD collection

37

38

Questions?

PEAQS Information Video:Youtube.com à “PEAQS”

Shaohua Hu, Ph.D. P.E.Manager, Measurement

Assessment and Research SectionCalifornia Air Resources Board

Shaohua.Hu@arb.ca.gov(916) 229-0911

TBSP Web Site: https://www.arb.ca.gov/msprog/onroad/tbsp/tbsp.htm

Tao Huai, Ph.D. Chief, Freight Emissions

Testing and Research BranchCalifornia Air Resources Board

Tao.Huai@arb.ca.gov(916) 229-0887