Regulated and Unregulated Emissions from Highway Heavy-Duty Diesel Engines Complying with U.S. Environmental Protection Agency 2007 Emissions Standards

Figures & data

Table 1. ULSD fuel properties used in the ACES program

ASTM Test	Test Property/Description	Units	Values
D1319	Aromatics	vol %	26.7
D5453	Sulfur content	ppm	4.5
D4052	API gravity at 60 °F	Dimensionless	33.8
	Specific gravity at 60 °F	Dimensionless	0.8561
	Density at 15 °C	g/L	855.6
D5291	Carbon content	wt %	86.32
	Hydrogen content	wt %	12.92
	Oxygen by difference	wt %	0.76
D613	Cetane number	Dimensionless	47.5
Notes: API= American Petroleum Institute.

Table 2. ACES engines ASTM average lube oil properties after 125 hr of engine operation

ASTM Test	Test Property/Description	Units	Fresh Lube Oil	Used Oil (average) ^a	Used Oil (minimum/maximum)
D445	Viscosity at 100 °C	cSt	15.19	16	13/21
D445	Viscosity at 40 °C	cSt	113.86	97	79/112
D5185	Element analysis
	Boron	ppm	<1	5	2/8
	Calcium	ppm	2268	2245	1879/2459
	Copper	ppm	<1	32	8/96
	Iron	ppm	1	44	16/72
	Lead	ppm	<1	4	1/6
	Magnesium	ppm	5	107	8/261
	Manganese	ppm	<1	3	1/5
	Phosphorus	ppm	1043	1024	978/1125
	Silicon	ppm	3	41	23/68
	Sodium	ppm	<5	8	6/10
	Tin	ppm	<1	3	1/4
	Zinc	ppm	1157	1199	1133/1269
Notes:
^aAverage was based on four analyses of the used lube oil, one per engine.

Figure 1. Overall experimental setup for the ACES program. A= 2007 heavy-duty diesel engine with aftertreatment. B= background bag sample of dilution air for CO, CO₂, NO_x, NO, THCs, CH₄, and C2–C12 speciation. C= regulated PM following CFR Part 1065 using 47-mm Teflo filter. D= impingers for carbonyls, alcohols, ions, and cyanide ion. E= sorbent traps for nitrosamines and Summa canister for SVOCs. F= auxiliary PM samples on 47-mm filters for inorganic ions (Fluoropore filter), XRF (Teflo filter), and inductively coupled MS (Fluoropore filter), DFI/GC (TX-40 filter). G= XAD traps for gas-phase semi-volatile compounds: PAHs, oxyPAHs, nitroPAHs, hopanes, steranes, carpanes, polar organics, high-molecular-weight alkanes and cycloalkanes, dioxins, furans. H= filter (8× 10 in. Zefluor) for particulate-phase semi-volatile compounds: PAHs, oxyPAHs, nitroPAHs, dioxins, furans, hopanes, steranes, carpanes, polar organics, high-molecular-weight alkanes, cycloalkanes, dioxins, and furans. I= UAEC PM mass using Teflo filter, OC/EC collection using a pair of quartz filters, size and number using EEPS, real-time total PM using DMM-230, real-time soot using MSS. J= proportional bag sample for hydrocarbon speciation of C2–C12 compounds. K= Horiba MEXA 7200 for THCs, CO, CO₂,NO_x, NO analyzer, and CH₄ analyzer. L= FTIR for N₂O.

Table 4. Average regulated emissions summary for four FTP composite cycles (1/7 × cold start+ 6/7 × hot start), one per ACES phase 1 2007 engine

	1998 EPA Standard (g/bhp-hr)	2007 EPA Standard (g/bhp-hr)	2007 Average Emissions (g/bhp-hr)	Percent Reduction Relative to 2007 Standard	Percent Reduction Relative to 1998 Standard
PM	0.1	0.01	0.0014 ± 0.0007	86	99
CO	15.5	15.5	0.48 ± 0.33	97	97
NMHC ^e	1.3 ^a	0.14	0.015 ± 0.024	89	97 ^d
NOx	4.0 ^b	1.2 ^c	1.09 ± 0.15	9	73
Notes:
^aEPA limit was based on THCs including CH4;
^bEPA limit went to 2.4 g/hp-hr in 2004;
^cAverage value between 2007 and 2009, with full enforcement in 2010 at 0.20 g/hp-hr;
^dValue is calculated based on average THC value of 0.034 g/hp-hr using the ACES phase 1 data;
^eNMHC is reported as the difference between measured THC and CH4.

Table 5. Average NO₂ emissions summary for all 12 repeats of the hot-start FTP transient cycle for all four 2007 ACES engines

	NO2 (g/hp-hr)	Percent NO2/NOx Ratio
2007 ACES engines (1.2 g/bhp-hr NOx )	0.73 ± 0.12	60.8
1998-compliant technology engines10,11 (4.0 g/bhp-hr NOx)	0.55 ± 0.01	13.8

Table 6. Summary of average unregulated emissions for all 12 repeats of the 16-hr cycles for all four 2007 ACES engines and for 2004-technology engines used in CRC E55/E5912 (dioxins were compared to 1998 levels).1 3

Compound	2007 Engines ^a (average ± SD, mg/hp-hr)	2007 Engines (average ± SD, mg/hr)	2004 Engines (average ± SD, mg/hr)	Average Percent Reduction Relative to 2004- Technology Engines
Single-ring aromatics	0.76 ± 0.35	71.6 ± 32.97	405.0 ± 148.5	82
PAHs	0.74 ± 0.25	69.7 ± 23.55	325.0 ± 106.1	79
Alkanes	1.64 ± 0.83	154.5 ± 78.19	1,030.0 ± 240.4	85
Hopanes/steranes	0.0011 ± 0.0013	0.1 ± 0.12	8.2 ± 6.9	99
Alcohols and organic acids	1.14 ± 0.27	107.4 ± 25.4	555.0 ± 134.4	81
NitroPAHs	0.0065 ± 0.0028	0.1 ± 0.0	0.3 ± 0.0	81
Carbonyls	2.68 ± 1.00	255.3 ± 95.2	12,500.0 ± 3,535.5	98
Inorganic ions	0.98 ± 0.40	92.3 ± 37.7	320.0 ± 155.6	71
Metals and elements	0.071 ± 0.032	6.7 ± 3.0	400.0 ± 141.4	98
OC	0.56 ± 0.50	52.8 ± 47.1	1,180.0 ± 70.7	96
EC	0.24 ± 0.05	22.6 ± 4.7	3,445.0 ± 1110.2	99
Dioxins/furans	6.6 × 10^−7± 5.5 × 10^−7	6.2 × 10^−5± 5.2 × 10^−5	NA	99 ^b
Notes: NA = not applicable.
^aData shown in brake-specific emissions for completeness. No comparable brake-specific emissions data were available;
^bRelative to 1998-technology engines.

Table 7. CARB toxic air contaminant average emissions for all 12 repeats of the 16-hr cycles for all four 2007 ACES engines and for 1994- to 2000-technology engines running over the FTP transient cycle.15

TAC No.	Compound	2007-Technology Engines ^a (mg/bhp-hr)	1994- to 2000-Technology Engines ^c (mg/bhp-hr)	Percent Reduction
1	Acetaldehyde	0.61 ± 0.27	10.3	93
2	Acrolein	<0.01	2.7	>99
3	Aniline	0.000150 ± 0.000075	NA	NA
4	Antimony compounds	<0.001	NA	NA
5	Arsenic	<0.0002	NA	NA
6	Benzene	<0.01	1.82	>99
7	Beryllium compounds	<0.0003	NA	NA
8	Biphenyl	0.013780 ± 0.001716	NA	NA
9	Bis[2-ethylhexyl]phthalate	^b	NA	NA
10	1,3-Butadiene	<0.01	1.7	>99
11	Cadmium	<0.00003	NA	NA
12	Chlorine (chloride)	<0.007	0.18	>96
13	Chlorobenzene and derivatives	^b	NA	NA
14	Chromium compounds	0.0007 ± 0.0003	NA	NA
15	Cobalt compounds	<0.0001	NA	NA
16	Cresol isomers	0.02727 ± 0.01233	NA	NA
17	Cyanide compounds	<0.05	NA	NA
18	di-n-Butylphthalate	b	NA	NA
19	Dioxins and dibenzofurans	0.00000066 ± 0.000000055	0.000066	99
20	Ethyl benzene	0.05 ± 0.04	0.49	90
21	Formaldehyde	1.90 ± 1.01	25.9	94
22	Hexane	<0.01	0.14	>93
23	Inorganic lead	<0.0001	0.0009	>89
24	Manganese	<0.00022	0.0008	>73
25	Mercury	<0.00016	NA	NA
26	Methanol	0.07 ± 0.13	NA	NA
27	Methyl ethyl ketone	<0.01	NA	NA
28	Naphthalene	0.0982000 ± 0.0423000	0.489	80
29	Nickel	0.0002 ± 0.0001	0.01	98
30	4-Nitrobiphenyl	<0.00000001	NA	NA
31	Phenol	0.00905 ± 0.00414	NA	NA
32	Phosphorus	0.0130 ± 0.0064	NA	NA
33	POM, including PAHs and derivatives	See Table 8	See Table 8	See Table 8
34	Propionaldehyde	0.01	1.8	>99
35	Selenium	<0.0001	NA	NA
36	Styrene	<0.01	0.73	>99
37	Toluene	0.26 ± 0.28	0.64	59
38	Xylene isomers and mixtures	0.35 ± 0.10	2.2	85
39	o-Xylene	0.13 ± 0.07	0.99	87
40 and 41	m- and p-Xylenes	0.20 ± 0.08	1.21	83
Notes: TAC= toxic air contaminant, POM= polycyclic organic matter.
^aThe significant figures signify the detection limit in mg/bhp-hr;
^bNot measured;
^cSD data were not provided by refs 15 and 16.

Table 8. PAH and nitroPAH average emissions for all 12 repeats of the 16-hr cycles for all four 2007 ACES engines and for a 2000-technology engine running over the FTP transient cycle.16

PAH and NitroPAH Compounds	2007 Engines ^a (mg/bhp-hr)	2000-Technology Engine ^a , ^b (mg/bhp-hr)	Percent Reduction
Naphthalene	0.0982000 ± 0.0423000	0.4829	80
Acenaphthylene	0.0005000 ± 0.0005000	0.0524	98
Acenaphthene	0.0004000 ± 0.0001000	0.0215	98
Fluorene	0.0015000 ± 0.0009000	0.0425	96
Phenanthrene	0.0077000 ± 0.0025000	0.0500	85
Anthracene	0.0003000 ± 0.0001000	0.0121	97
Fluoranthene	0.0006000 ± 0.0006000	0.0041	85
Pyrene	0.0005000 ± 0.000400	0.0101	95
Benzo(a)anthracene	<0.0000001	0.0004	>99
Chrysene	<0.0000001	0.0004	>99
Benzo(b)fluoranthene	<0.0000001	<0.0003	>99
Benzo(k)fluoranthene	<0.0000001	<0.0003	>99
Benzo(e)pyrene	<0.0000001	<0.0003	>99
Benzo(a)pyrene	<0.0000001	<0.0003	>99
Perylene	<0.0000001	<0.0003	>99
Indeno(123-cd)pyrene	<0.0000001	<0.0003	>99
Dibenz(ah)anthracene	<0.0000001	<0.0003	>99
Benzo(ghi)perylene	<0.0000001	<0.0003	>99
2-Nitrofluorene	0.00000360 ± 0.00000410	0.0000650	94
9-Nitroanthracene	0.0000148 ± 0.0000213	0.0007817	98
2-Nitroanthracene	0.00000040 ± 0.00000090	0.0000067	94
9-Nitrophenanthrene	0.00002110 ± 0.00002090	0.0001945	89
4-Nitropyrene	<0.00000001	0.0000216	>99
1-Nitropyrene ^c	0.00001970 ± 0.00002430	0.0006318	97
7-Nitrobenz( a )anthracene	0.00000020 ± 0.00000020	0.0000152	99
6-Nitrochrysene	<0.00000001	0.0000023	>99
6-Nitrobenzo( a )pyrene	<0.00000001	0.0000038	>99
Notes:
^aThe significant figures signify the detection limit in mg/bhp-hr;
^bSD data were not provided by ref 15.
^cPrevious work showed artifact formation during filter collection of the compounds highlighted in bold.

Table 9. Elemental average emissions for all 12 repeats of the 16-hr cycles for all four 2007 ACES engines and for 1994- to 2000-technology engines running over the FTP transient cycle.15,16

Element	2007-Technology Engines ^a (mg/bhp-hr)	1994- to 2000-Technology Engines ^a , ^b (mg/bhp-hr)	Percent Reduction
Zinc	0.0027 ± 0.002	1.16	>99
Sulfur	0.291 ± 0.129	2.89	>99
Calcium	0.0115 ± 0.0078	0.02	>43
Silicon	0.0022 ± 0.0014	0.02	>89
Copper	0.0004 ± 0.0002	0.78	>99
Lead	0.0784 ± 0.0731	1.83	>96
Iron	0.0152 ± 0.0092	1.66	>99
Chloride	<0.001	0.18	>99
Ammonia	<0.001	11.5	>99
Notes:
^aThe significant figures signify the detection limit in mg/bhp-hr;
^bSD data were not provided by refs 15 and 16.

Table 10. Average element emissions rate and composition used in Figure 3 for all 12 repeats of the 16-hr cycles using all four 2007 ACES engines

Element	Average Emissions (μg/hp-hr)	Percent of Measured Elemental Mass	Percent of Total PM Mass
Sodium	24.4± 9.4	30.8	1.1
Magnesium	3.6± 1.4	4.5	0.2
Aluminum	2.5± 0.4	3.1	0.1
Silicon	2.2± 1.4	2.7	0.1
Phosphorous	13.3± 6.4	16.8	0.6
Chlorine	1.0± 1.0	1.2	0.0
Potassium	1.1± 1.1	1.4	0.1
Calcium	11.5± 7.8	14.5	0.5
Titanium	0.38± 0.43	0.5	0.0
Vanadium	0.01± 0.01	0.0	0.0
Chromium	0.70± 0.30	0.8	0.0
Manganese	0.22± 0.14	0.3	0.0
Iron	15.2± 9.2	19.1	0.7
Nickel	0.22± 0.1	0.3	0.0
Copper	0.37± 0.15	0.5	0.0
Zinc	2.7± 2.2	3.3	0.1

Figure 3. Average element emissions rate and composition for all 12 repeats of the 16-hr cycles using all four 2007 ACES engines. As a percentage of total PM: sodium (1%), phosphorus (0.6%), calcium (0.5%), iron (0.7%), and zinc (0.1%). Note that the graph shows the percent of total elements and not PM; PM was collected from the full-flow CVS for these analyses.

Table 11. Summary of data plotted in Figure 5

Species	Average Emissions (mg/hp-hr)	Species State as Collected or Measured	Collected from (location/collection)
PAH	0.74± 0.25	Gas and particle phase	Full-flow CVS/Zefluor filter/XAD
OxyPAHs	0.005± 0.002	Gas and particle phase	Full-flow CVS/Zefluor filter/XAD
NitroPAHs	0.0007± 0.0003	Gas and particle phase	Full-flow CVS/Zefluor filter/XAD
Polar	1.14± 0.27	Gas and particle phase	Full-flow CVS/Zefluor filter/XAD
Alkanes	1.64± 0.83	Gas and particle phase	Full-flow CVS/Zefluor filter/XAD
Hopanes	0.0006± 0.0011	Gas and particle phase	Full-flow CVS/Zefluor filter/XAD
Steranes	0.0004± 0.0008	Gas and particle phase	Full-flow CVS/Zefluor filter/XAD
C6–C12 speciation	3.78± 1.38	Gas phase	Full-flow CVS/Tedlar bag
Nitromethane and ethane	1.18± 1.38	Gas phase	Full-flow CVS/Summa canister
EC	0.24± 0.05	Particle phase	Exposure chamber/quartz filter
OC	0.56± 0.50	Particle phase	Exposure chamber/quartz filter
Elements	0.07± 0.03	Particle phase	Full-flow CVS/Teflo filter
Sulfate	0.98± 0.45	Particle phase	Full-flow CVS/fluoropore filter
PM	2.27± 0.7	Particle phase	Exposure chamber/Teflo filter
Notes: Data are based on the average emissions for all 12 repeats of the 16-hr cycles using all four 2007 ACES engines.

Figure 5. Maximum potential of particle-phase emissions using chemical composition compared with filter weighing and other chemical makeup. Data plotted based on the average emissions for all 12 repeats of the 16-hr cycles using all four 2007 ACES engines. PM for OC/EC was collected from the exposure chamber; PM for sulfate, elements, and gas- and particle-phase semi-volatiles and volatiles were collected from the full-flow CVS.

Table 3. Test matrix with the number of repeated runs for each of the four 2007 ACES engines used in the ACES program (only the highlighted events in are reported in this paper)

Cycle	Regulated Pollutants (number of repeats)	Unregulated (number of repeats)
Hot-start FTP	3	^a , ^f
Mode 1, rated speed, 100% load, 20 min	3	^a , ^f
Mode 3, rated speed, 50% load, 20 min	3	^a , ^f
Mode 5, peak torque speed, 100% load, 20 MIN	3	^a , ^f
Cold-start FTP, 20 min	1	^a , ^f
Hot-start FTP, 20 min	6 ^b	6 ^b
Composite CARB HHDDE cycle mode 1, 2, and 5 (creep, transient, and idle), CARBX-ICT, 39 min	2	2
Composite CARB HHDDE cycle mode 3 and 4 (cruise and high-speed cruise), CARBZ-CH, 48 min	2	2
16-hr transient cycle, 16 hr	3	3
Tunnel blanks, ^c 20 min	4 for first engine and 3 for others	4 for first engine and 3 for others
Tunnel background, ^d 16 hr		1
16 hr for dioxins and furans only, ^e 16 hr		1
Notes: HHDDE= highway heavy-duty diesel engine.
^aOnly real-time particle size, number, total mass, and solid mass measurements were performed for these tests.
^bThree hot-start FTP runs with blow-by and three without blow-by.
^cTunnel blank is a 20-min test run exactly like an engine test, except the engine is off: one tunnel blank after cleaning the CVS tunnel but before running the engine; a second tunnel blank after finishing the six hot-start FTP runs, which is also before starting the CARB composite modes; a third tunnel blank after finishing the CARB composite modes but before the 16-hr transient cycle; and a fourth tunnel blank after finishing the 16-hr transient cycle.
^dTunnel background is a 16-hr test in which samples are taken from the dilution air immediately downstream of the CVS HEPA filter. Tunnel background dilution air was collected for 16 hr using an 8 × 10 Zefluor filter followed by four XAD traps.
^eDioxins and furans were collected separately for 16 hr on engines A, C, and D using 8 × 10 Zefluor filters followed by four XAD traps.
^fData were shared with each engine manufacturer to make sure that the engine emissions performance complied with the manufacturer's expectation and to get approval to proceed with the program.

Figure 2. Average PM emissions rate and composition for all 12 repeats of the 16-hr cycles using all four 2007 ACES engines. The filter for weighing was collected from the exposure chamber using a Teflo filter; OC and EC were collected from the exposure chamber using a quartz filter and analyzed using TOT; and sulfate and elements were collected from a full-flow CVS on fluoropore and Teflo filters, respectively, and were analyzed using ion chromatography and XRF, respectively

Figure 4. Average particle-phase semi-volatile emissions rate and composition for all 12 repeats of the 16-hr cycles using all four 2007 ACES engines. Particle-phase semi-volatiles were collected from the full-flow CVS.

Figure 6. Average particle number emissions comparison between the 2007 ACES engines with and without C-DPF regeneration and a 2004-technology engine. Data for the 2007 ACES engines were based on 12 repeats of the FTP transient cycle and 12 repeats of the 16-hr cycle using all four ACES engines. Data for the 2004-technology engine were based on six repeats of the FTP transient cycle. Data for the 2007 ACES engines were taken from exposure chamber and from full-flow CVS for the 2004-technology engine.

Figure 7. Average size distribution comparison between all 2007 ACES engines with and without C-DPF regeneration and a 2004-technology engine without a DOC and/or a C-DPF. Data for the 2007 ACES engines were taken from the exposure chamber for the 4-hr segments of the 16-hr cycle. Data for the 2004 engine were taken from the full-flow CVS for the FTP transient cycle. GNMD= geometric number mean diameter, GSD= geometric standard deviation.

Figure 8. Example of particle number emissions and C-DPF outlet temperature during two separate 4-hr segments of the 16-hr cycle with and without C-DPF active regeneration using one of the ACES engines. Plotted also for comparison are the number emissions from a 2004-technology engine without DOC/C-DPF using the FTP transient cycle. The same FTP data with the 2004-technology engine are plotted in three separate locations to coincide with the FTP transient cycle that is part of the 4-hr segment of the 16-hr cycle.

Figure 9. Nuclei-mode particle number in the sub-30-nm size range plotted as a percentage of total particle number during a 4-hr segment of the 16-hr cycle with active C-DPF regeneration. Data are similar to the data shown in Figure 8 for the ACES engine with active regeneration but are plotted as the percentage of total number for sub-30-nm particles.

Figure 10. Total and soot particle mass emissions rate profile during a 4-hr segment of the 16-hr cycle with C-DPF active regeneration

Zhen , F. , Clark , N. , Bedick , C. , Gautam , M. , Wayne , W. , Thompson , G. and Lyons , D. 2009 . Development of a Heavy Heavy-Duty Diesel Engine Schedule for Representative Measurement of Emissions . Journal of the Air & Waste Management Association , 59 : 950 – 959 . doi: 10.3155/1047-3289.59.8.950

 Web of Science ®Google Scholar

Bedick , C. , Clark , N. , Zhen , F. , Atkinson , R. and McKain , D. 2009 . Testing of a Heavy Heavy-Duty Diesel Engine Schedule for Representative Measurement of Emissions . Journal of the Air & Waste Management Association , 59 : 960 – 971 . doi: 10.3155/1047-3289.59.8.960

 Web of Science ®Google Scholar

Test Report of Mobile Source Emission Control Devices: Johnson Matthey PCRT2® 1000, Version 2, Filter+ Diesel Oxidation Catalyst; U.S. Environmental Protection Agency (EPA) Environmental Technology Verification; 2009 http://www.epa.gov/etv (http://www.epa.gov/etv) (Accessed: 2010 ).

 Google Scholar

Emission Standards for 1994 and Later Model Year Diesel Heavy-Duty Engines and Vehicles. CFR, Part 86.094-11, Title 40, 2003.

 Google Scholar

Khalek, I.A.; Bougher, T.; Merritt, P. Phase 1 of the Advanced Collaborative Emissions Study; Coordinating Research Council (CRC) Report ACES-Phase 1; CRC: Alpharetta, GA, 2009 http://www.crcao.org/publications/emissions/index.html (http://www.crcao.org/publications/emissions/index.html) (Accessed: 2010 ).

 Google Scholar

An Inventory of Sources and Environmental Releases of Dioxin-Like Compounds in the United States for the Years 1987, 1995, and 2000; U.S. Environmental Protection Agency; National Center for Environmental Assessment; Office of Research and Development: Washington, DC, 2006 http://www.epa.gov/ncea/pdfs/dioxin/2006/dioxin.pdf (http://www.epa.gov/ncea/pdfs/dioxin/2006/dioxin.pdf) (Accessed: 2010 ).

 Google Scholar

Ullman , T. , Smith , L. , Anthony , J. , Slodowske , W. , Trestrail , B. , Cook , A. , Bunn , W. , Lapin , C. , Wright , K. and Clark , C. 2003 . Comparison of Exhaust Emissions, Including Toxic Air Contaminants, from School Buses in Compressed Natural Gas, Low Emitting Diesel, and Conventional Diesel Engine Configurations. Society of Automotive Engineers (SAE) Paper 2003-01-1381 , Warrendale , PA : SAE .

 Google Scholar