Composite Cycle

130

110

90

aneA pazyewi0N

A3

30

time (sec.)


where o is the hydrogen to carbon ratio, G, is the total mass of carbon, in grams. and M is the
mass of fuel consumed, in pounds. .

400
+ + br +
350 ty + + +{
e e *% '@ 25% torque ;
300 te x x e © | im 40% torque
@ 250+* x x  * * is 50% torque |
& 200 lx x x x * x x x | [x 60% torque |
g a4 4 a 4 4 A a | (x 75% torque |
3 10 te om a so 8 o@ s w| je 85% torque
Wot, 4 . e+e . fe | [#100 % torque!
50
i)
500 1000 1500 2000 2500 3000
spéed (rpm)

Figure 1. Steady-state emission points under the engine’s torque curve.

Il. RESULTS AND DISCUSSION

The table below shows the emissions results from the transient test cycles. The backhoe,
crawler and composite cycles results are the average of three runs. The reproducibility of the
results was good as shown in the Appendix, and the standard deviation was consistently within 5
percent of the average values. The Hot Start of the FTP was performed twice and the brake
specific results were also within 5 percent from the averaged values.


Lv

Steady state cycles

ISO 13 mode.
NOx HC PM BSFC | Efficiency |g NOx/kg fuel)
mode_|_speed_] % torque hp __ghr_gfohp-he ‘ne | toibhp-he

1 550 0 02 11.40 54.08 14.32 66.33 2.04 8.95 ° 6.78 0.02 176
2 2900 | 100 169.1 758.87 4.01 3.213 0.02 71.70 0.36 041 034 218
3 2900 rE 1448 743.91 5.14 22.48 0.16 31.73 022 oat Os 277
4 2900 60 962 650.32 6.76 44.84 0.47 16.97. 0.18 0.44 0.31 34.0
5 2900 “25 482 478.90 9.93 61.88 1.28 19.17 0.40 0.60 0.23 36.7
6 2900 10 104 357.00 18.36 60.35 ald 25.92 1.32 Wa 0.12 36.6
7 550 0 O41 14.28 113.10 WT 139.90. 2.63 20.67 W175 0.01 212
8 1740 100 123.5 47.40 2.81 10.24 0.08 a7 0.22 0.36 0.39 TA
o 1740 15 934 278.20 2.88 21.66 0.23 11.68 0.13 0.38 0.37 WS
10 1740 50 62.0 161.60 2.61 27.75 0.45 16.19 0.26 0.39 0.36 149
" 1740 2s 31.0 86.05 2.78 46.37 1.50 11.18 0.36 0.48 0.29 12.8
12 1740 10 123 48.63 3.96 57.99 4.73 10.72 087 0.78 0.18 11.2
13 550 o 02 14.80 66.75 15.06 62,57 2.91 12.76 6.70 0.02 22.0

Weighted: 1SO 13 mode 9333 «417.73 4.73-25.59 029 «20.770.

1s0 C1 9437 430.41 4.66 26.95 029 «26 83s«0.28



2. S. Ashley, “Diesel Cars Come Clean”, Mechanical Engineering, Vol. 119, No.8. August 1997,
pp. 52-56, ASME.

3.G. Stumpp and Mario Ricco, “Common Rail-An Attractive Fuel Injection System for
Passenger Car DI Diesel Engines”, SAE 960870.

4. Y. Yamaki, et al, “Application of Common Rail Fuel Injection System to a Heavy-Duty Diesel
Engine”, SAE 942294.

"5. See endnote 2--S. Ashley, “Diesel Cars Come Clean”,1997.

6.W. Boehner and K. Hummel, “Common Rail Injection System for Commercial Diesel
Vehicles”, SAE 970345.

VI. ACKNOWLEDGMENTS

Special thanks to the Engine Testing Group in the Testing Services Division at U.S.
EPA's National Vehicles and Fuel Emissions Laboratory for their technical suppport of this
project. Also we appreciate the help of Dr. Joe Norbeck, from the University of California-
Riverside for his suggestions and comments on this report.


torque (ft-lb)
nD
Q
Oo
1

i

is}

3
1

150 4

100 5

50 + T T T

500 1000 1500 2000 2500 3000
speed (rpm)

Figure 2. NOx emissions (g/bhp-hr) map.

400

350 4

300 4

torque (ft-Ib.)
B 8
1 L

150 +

100 +

50 T T T T

500 1000 1500 2000 2500 3000
speed (rpm)

Figure 3. PM emissions (g/bhp-hr) map.



NOx HC PM BSFC g NOx/kg
Cycle bhp-hr_|(g/bhp-hr) (eine (g/bhp-hr) | = (Ib/bhp-hr) Efficiency of fuel
Backhoe 45 5.14 0.89 0.20 0.376 0.37 30.1
Crawler 16.6 3.42 0.37 0.16 0.320 0.43 23.6
Composite | 20.9 4.11 0.41 0.19 0.377 0.37 24.0
FTP (HS) 12.2 4.48 0.60 0.22 0.406 0.34 24.3
FTP (CS) 12.2 4.67 0.62 0.25 0.428 0.32 24.1

Table I. Emission results for various transient cycles.

It is worth noting that the 43% thermal efficiency calculated for the Crawler cycle was
much higher than the efficiencies on the other transient cycles. Furthermore, the thermal
efficiency determined from steady-state data reaches a maximum of 42% at one point only. Since
the overall fuel consumption, and as a result the thermal efficiency, during the Crawler cycle was
very consistent for all three cycles run, it is not possible to explain at this point the reason for
such high thermal efficiency. Results for the 13 mode and ISO Cl steady state cycles are shown
in Table I. The weighted brake-specific NOx and PM values were similar for both cycles as can
be seen from the Table. Detailed emissions data is presented in the Appendix.

Cycle NOx (g/bhp-hr) | HC (g/ohp-hr) | PM (g/bhp-hr)
ISO Cl (8 mode) 4.66 0.29 0.28
ISO 13 mode 4.73 0.29 0.34

Table I. Emission results from two steady-state cycles.

Results from the steady state modes sampled under the torque curve were plotted as
contour graphs. Figures 2 to 6 show the brake-specific emissions, fuel consumption and thermal
efficiency plots. As shown in Figure 2, the lowest NOx values occur from 1300 to almost 2000
rpm across almost the entire operating torque range. The lowest NOx value was 2.61 g/bhp-hr at
1725 rpm and 153 ft-lb. The PM emissions map shown in Figure 3 exhibit its lowest values at
low speeds and high loads. Overall, however, PM emissions are higher than the current 0.1
g/bhp-hr U.S. standard. Both the BSFC and thermal efficiency maps display, as expected, similar
trends: the lowest BSFC’s and highest efficiencies occur at the low speed-high torque regions
while the opposite is true at the high speed-low torque region.


transient cycles

Baseline Emissions Data

Cycle: Crawler
Test No. 1 2 3 avg. std. dev.

NOx (g/ohp-hr) 3.386 3.408 3.467 3.420 0.042
HC (g/ohp-hr) 0.386 0.371 0.351 0.369 0.018
CO (g/ohp-hr) 0.792 0.789 0.803 0.795 0.007
PM (g/bhp-hr) 0.159 0.167 0.153 0.160 0.007
BSFC (Ib/bhp-hr)__0.313 0.319 0.329 0.320 0.008

(Cycle: Backhoe 1 2 3 avg. std. dev.
INOx 5.196 5.256 4.979 5.144 0.146
HC 0.815 0.891 0.960 0.889 0.073
co 2.521 2.496 2.398 2.472 0.065
PM 0.201 0.204 0.205 0.203 0.002
IBSFC (Ib/ohp-hr)__0.387 0.381 0.361 0.376 0.014
Cycle: Composite 1 2 3 avg. std. dev.
NOx 4.285 4.159 3.891 4.112 0.201
HC 0.423 0.413 0.387 0.408 0.019
co 1.211 1.104 1.181 1.165 0.055
PM 0.198 0.186 0.201 0,195 0.008
BSEC (Ib/bhp-hr) 0.382 0.380, 0.368 0.377. 0,008
Cycle: FTP-HS 1 2 3 avg. std. dev.
INOx 4,532 4.429 4481

HC 0.577 0.626 0.602

co 1.673 1.674 1.674

PM 0.216 0.222 0.219

BSFC (Ib/ohp-hr) 0.409 0.403 0.408

Cycle: FTP-CS. 1 2 3 avg. std. dev.
NOx. 4.671 .

HO 0.626

ico 1,883

PM 0.251
BSFC (Ib/bhp-hr)__0.428

Ag


torque (ft-Ib.)

50 T “T TM T
500. 1000 1500 2000 2500 3000
speed (rpm)

Figure 6. Brake-specific fuel consumption (in lb/bhp-hr) map.

It was attempted to compare the emission test results from this engine with other
commercially available engines of similar displacement and power rating. Unfortunately there
are almost no naturally-aspirated heavy-duty engines currently available since most engines sold
in the U.S. for the heavy-duty truck market are turbocharged.

IV. SUMMARY AND CONCLUSIONS

We have obtained baseline emission data from a common-rail heavy-duty diesel engine.
The engine uses a very flexible common-rail fuel injection system that is controlled electronically
and is capable of very high injection pressures. For the transient cycles, the brake-specific
emissions were relatively high when compared to the 1998 US highway standard of 4.0 g/bhp-hr
NOx. On the FTP, for example, the resulting NOx emission level was 4.48 g/bhp-hr. PM
emissions were also high relative to the 0.1 g/bhp-hr U.S. standard. Steady-state emissions and
efficiency maps were also produced from the test data. The maps show that the lowest NOx
region (of about 3.0 g/bhp-hr) occur at intermediate speeds, while at rated speed the NOx can
increase to 4.15 g/bhp-hr at full load.

V. REFERENCES

1. Federal Register, Vol. 62, No. 203, October 21, 1997, pp.54694-54730.


SEPA

United States Air and Radiation EPA420-R-97-002
Environmenta! Protection December 1997
Agency

Office of Mobile Sources

Exhaust Emissions From A
Heavy-duty Diesel Engine
Equipped With A High
Pressure Common Rail
Fuel Injection System

& Printed on Recycled Paper


Backhoe Cycle

[-—— Speed,
—--—-Torque!

ogy
vor
ayy
ze
ot
4 oor
vee
age
zse
| gece
oze
| voe

geez
‘| zzz
| osz
ove
vez
802
ze
QL
oot
Jove
ezt
zit
96
os
v9
ay
ze
9

°
wo

90
70
30
10
-10

SaN[eA Pez{[BUWs0N

Al

time (sec.)


VI. Appendix

Al. Backhoe Cycle

A2. Crawler Tractor Cycle
A3. Composite Cycle

A4. Fuel Specifications

AS. Steady-state emissions data.

A7. ISO 13 mode and C1 data.

A8. Transient cycle data.

10


400

3504 ~—-~< en

300 4 |

no

a

co}
1

05—

ny

fo}

6
1

torque (ft-Ib.)

a
o
1

100 4

50 + T T T T
500 1000 1500 2000 2500 3000
speed (rpm)
Figure 4. HC emissions (g/bhp-hr) map.

400

350 4

300 +

n

a

°
n

ix

f=}

o
L

torque (ft-Ib.)

150 +

100 4

50 T T T T
500 1000 1500 2000 2500 3000
speed (rpm)

Figure 5. Thermal efficiency map .


engine was setup in a heavy-duty engine test cell at EPA’s National Vehicle and Fuel Emissions
Laboratory (NVFEL). Inlet depression was set at -7.9 in H,O at rated point and the exhaust
backpressure at 6.4 in. Hg at rated point. The fuel used for this study was diesel No. 2. The fuel
specifications are included in the Appendix.

B. Test cycles
The following transient test cycles were performed:

a. Heavy-duty Federal Test Procedure (FTP): cold and hot start.
b. Crawler-tractor cycle

c. Backhoe loader cycle

d. Composite cycle

Cycles b., c. and d. were developed by Southwest Research Institute under separate
contracts with the Engine Manufacturers Association (EMA) and the EPA. Although there are no
final reports currently available with detailed information about the development of the cycles,
the torque and speed traces are shown in the Appendix. The FTP was run by following the
procedure outlined in the Code of Federal Regulations (CFR) Title 40, Part 86, Subpart N. Both
the ISO 13 mode (UN-ECE R49) test and the C1 (8 mode), which are described in the ISO 8178-
4 document, were also performed. In addition, a set of 56 steady-state modes were run twice to
develop an emissions map under the torque curve of the engine. Each steady-state mode was run
for approximately five minutes, followed by three minutes of exhaust emissions measurements.
Figure | shows the specific map points tested under the engine’s torque curve.

Exhaust emissions were sampled from a dilution tunnel and recorded continuously. The
emission sampling procedure is described in 40 CFR Part 86 Subpart N. Brake specific NOx,
HC and PM emissions, in g/bhp-hr, were determined from the gas concentrations that were
measured continuously. The efficiency and fuel consumption results were obtained from carbon
balance calculations. The following carbon balance equations were used:

_ 12.01
2 12.011 +1.0080

G,2RyHC pgge*0-429CO ypyest0-273CO4_

mass


DATE OF SHIPMENT

ene . 08-16-96
Certificate of Analysis | cusroueronoen vo.
GAC1O11-NTLX
PHILLIPS CHEMICAL COMPANY INVJREQN. NO.
A DIVISION OF PHILLIPS PETROLEUM COMPANY 666279
SPECIALTY CHEMICALS,
PO. BOX 968 CONTAINER NO.
BORGER. TX 79008-0968 TRLA #358
9.05 SULFUR OIESEL FUEL
LOTS-$46x
RESULTS SPECIFICATIONS wi
Corrosion 1A Report ASTM 0-130
Specific Gravity, 60/60 2468 Report ASTM 0-4062
API Gravity 35.8 32.97 ASTM D-1298
‘Sulfur, Wt% 036 0.03 - 0.05 ASTM 0-2622
Flash Point, °F, PM yal 130 Mie, ASTM 0-03
Pour Point, °F 4 Report ASTM 0-07
Cloud Point, *F r) Report ASTM D-2500
Viscosity, cs 40C 2.67 20-34 ASTM 0-445,
Carbon, wt% . Report
Hydrogen, wrt . Report
Ash, wi% 0.01 Report ASTM 0-482
Net Heat of Combustion, 1844 Report ASTM 0-3338
Particutate Matter(mgT) 8 15 Max. ASTM 0-2276
Catane index 470 sped ASTM 0-976
Catane Number 465 0-48 ASTM 0-613
‘TO BE REPORTED LATER
‘ ASTM 0-86
18P wm 40-400
% 410
10% aa 400-460
20% 453
20% 472
40% Deed
50% $02 470-540
60% 516
70% 3
20% 558
90% sos 560-630
95% 61S
ep 2 610-690
Loss 08
Residue or
HYDROCARBON TYPE, vOL% ASTM D138
Aromatics 320 27 Min,
Olefins 38
Saturetes 2
EAAjam
081696
RF3700

A4


ov

Steady-state emissions

48 a2 [ee 87 | 88 447.2 [1.96 | 0.541 19.65 [051] 027
49 2312 141 621 . 203.7 1 ; 0.43 | 032°
50 2312 177, 19 3.31 257.9 0.69 . ‘6 | 041
51 2312 212 931 | 3.16 204.2 053 0.204 36.61 | 0.39 ;
52 2312 264 116.4 3.01 950.4 0.27 0.154 40.79 |035| 039
2312 300 132.2 3.21 424.4 0.14 0.165 49.69 | 038 | 037
54 2312 353. 155.5 3.11 483.6 0.02 0.237 58.64 | 038 | 0.36
5S 2900 88 48.6 9.75 474.1 1.55 0.584 2733 | 056] 025
56 2900 141 77.9 7.66 596.7 0.89 0.276 352 | 045| 0.31
57 2900 176 972 679 660 07 0.212 4064 [042 {| 033
58 2900 21 1165 6.15 7166 0.56 0.169 46.61 | 04 | 0.34
9 2900 264 145.8 5.26 766.8 03 0.175 56.95 | 0.39 | 0.35
60 2900 299 165.0 477 787.1 0.12 0.212 6468 | 0.39 | 0.35
{61 2900 352 169.4 4.15 766 0.02 0.326 7498 | 039{ 0.36



I. INTRODUCTION

In October, 1997 the Environmental Protection Agency (EPA) promulgated new exhaust
emission standards for heavy-duty engines'. The new standards, to become effective in the year
2004, will help reduce exhaust emissions for oxides of nitrogen (NOx) to approximately 2 g/bhp-
hr while maintaining the current standard for particulate matter at 0.1 g/bhp-hr. Although these
lower emission levels will present a challenge in the design of new engines, there are
technologies available that will allow emission reductions without significantly affecting
performance and fuel economy.

Over the last several years, advances in the development of electronic controls and high-
pressure fuel injection systems have allowed manufacturers more flexibility in the control of the
delivery of the fuel during the combustion event and higher injection pressures. High injection
pressures, for example, allow better air/fuel mixing, which result in reduced formation of
particulate matter. Common-rail fuel injection systems are one example of the type of
technologies that are being introduced in the market and that allow both better engine
performance and low emissions?,’.

Common-rail injection systems today are attracting a lot of attention due to their
flexibility by allowing the control of many engine parameters independently. In that type of
system the fuel is accumulated in a rail at high pressures and the injection pressure is increased
by varying the amount of fuel discharged by the supply pump*. Contrary to conventional fuel
injections systems, the common-rail type allows to vary the injection pressures independent of
engine speed and load. In in-line fuel systems the injection pressure results from the metered fuel
quantity being pushed through the nozzle orifice by a piston with a velocity that is proportional to
the engine speed®. The flexibility in varying fuel injection pressures and fuel quantity allow
common-rail systems to produce higher injection pressures and higher torque at low speeds than
systems using in-line pumps. Another advantage of common-rail systems is that, since the
injectors use electromagnetic valves or solenoids, strategies such as rate shaping, pilot injection
or even post injection can be used to further improve performance and exhaust emissions®.

We have obtained baseline emissions data over a variety of transient and steady state
cycles from a heavy-duty diesel engine that utilizes a common-rail fuel injection system. Data
show that even though this engine emits NOx and PM levels that are than the 1998 U.S. heavy-
duty emission standards on the Federal Test Procedure, the steady-state data show that the engine
is capable of achieving NOx emission levels in the order of 3 g/bhp-hr.

Il. TESTING PROCEDURES
A. Engine

The engine was in new condition and already undergone break-in. The engine is naturally
aspirated, with a total displacement of 7.9 liters and its rated power is 193 hp at 2900 rpm. The

ie)


TECHNICAL REPORT

EXHAUST EMISSIONS FROM A HEAVY-DUTY DIESEL ENGINE EQUIPPED WITH A
HIGH PRESSURE COMMON RAIL FUEL INJECTION SYSTEM

by

Jaime Pagan
U.S. Environmental Protection Agency
Office of Air and Radiation
Office of Mobile Sources
Engine Programs and Compliance Division

December, 1997

NOTICE

This technical report does not necessarily represent final EPA decisions or positions. It is intended to present
technical analysis of issues using data which are currently available. The purpose in the release of such reports is to
facilitate the exchange of technical information and to inform the public of technical developments which may form

the basis for a final EPA decision, position or regulatory action.


Crawler Tractor Cycle

— — = 1
NN te
eS

oo 42

120

100

80
0)
40
20
v1)

anjeA pezjeuWON

A2

time(sec.)


Steady-state emissions

sv

Mode} Speed (rpm) HC (ofbhp-ha] PM (o/bhp-hy)

ee a 1 0.3 P43 |

2 600 =

3__| 600 170 196 0.144

| 600 204 233 0.131

Ss 600 262 20.9 0.096

6 600 289 33.0 0.085

7 600 340. 38.8 0.108

a 785 87 13.4 0.25

9 785 140 209 0.161

10 785. 175 | 261 0.155 r ’

tt 785 210 31.4 0.132 1044 {0.33 0.41 29.96
12 785 261 42.0 0.093 13.78 [033 [042 34.74
13, 785 207 444 0.086 454 [033 [ 042 34.93
14 785 350 52.3 0.115, wa {osa{ 0.41 92.48
15 1137 94 20.3 0.259 o37_ | 041 | 0.34 17.37
16 1137, 150. 32.5 0.157 11.68 | 0.36 0.38 18.88
17 1137 168 40.7 0.133 14.02 | 0.34 0.4 20.86
16 1137, 225 487 0.13 1645 | 0.34! 041 22.46
1 1137 275 59.4 . 0.115 19.91 | 033] 0.41 24.32
20 1137 319 69.1 023 0.092 2325 [o34| 041 2397
21 1137 375 613 0.12 0.19 27.75 | 034| 04 21.67
22 1490 92 26.1 1.47 0.366 11.38 | 0.44 [0.32 14.26
23 1480 146 414 072 0.203 1557 [0.38 | 0.37 16.07
24 1490 183 51.9 0.53 0.203 187- | 0.36

25 1490 220 62.4 x 0.43 0.104 21.97 | 0.35

26 1490 287 815 3.16 257.6 0.26 0.163 27.99 | 0.34

27 1490 311 633 327 288.7 02 (0.089 30.36 | 0.34

28 1490 366 1222 2.61 343.5 0.08 0.156 96.13 | 0.35

29 1725, 96 31.5 2.66 83.67 1.46 0.374 1441) | 0.45

30 1725 153 502 261 130.9 0.72 0.316 19.48_| 0.39

31 1725 191 62.7 164.9 0.55 0.293 2321 | 037

32 1725 220 75.4 199.7 0.38 0.189 27.15 | 0.36

33 1725. 265 67.1 246.6 0.20 0.133 31.07 | 0.36

34 1725 325 106.9 322.8 0.13 0.104 37.68_| 0.35

35 1725 382 125.8 363.5 0.01 0.181 44it [03s | 03

at 1960 93 348 107.4 174 0.408 16.34 | 0.47

142 1960 148 65.3 163.8 0.9 0.308 22.03 | 0.4

43 1960 185 69.1 ___|_2129 [0.63 0.213 26.18 | 0.38

laa | 1960 222 83.0 257.2 05 0.162 30.61 | 0.37

45 1960 264 987 303.9 |" 0.35 0.139 35.89 | 0.36

46] 1960 315 117.7 | 381.3 02 0.126 42.47 | 0.36.

la7__| 1960 370 138.0 4474 0.05 0.151 49.31 | 0.36