United States

Environmental Protection

Agency

Air and Radiation EPA420-R-00-002

February 2000

Analysis of

Commercial Marine

Vessels Emissions and

Fuel Consumption Data

 Printed on Recycled Paper
EPA420-R-00-002

February 2000

Analysis of Commercial Marine Vessels

Emissions and Fuel Consumption Data

Office of Transportation and Air Quality

U.S. Environmental Protection Agency

Prepared for EPA under contract to

Sierra Research by

Energy and Environmental Analysis, Inc.

EPA Contract No. 68-C7-0051

Work Assignment No. 1-10

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.
i

TABLE OF CONTENTS

Page

1. INTRODUCTION ...................................................................................................... 1-1

2. REVIEW OF RELEVANT DATA ............................................................................. 2-1

2.1 Introduction ..................................................................................................... 2-1

2.2 Findings on Reports Providing Emissions Data .............................................. 2-1

2.3 Summary of Reports Analyzing Emissions Data ............................................ 2-3

2.4 Recommendations for Analysis ....................................................................... 2-6

3. EMISSION FACTOR DEVELOPMENT .................................................................. 3-1

3.1 Introduction ..................................................................................................... 3-1

3.2 Lloyd’s Emission Test Data ............................................................................ 3-2

3.3 U.S. Coast Guard Emission Test Data ............................................................ 3-6

3.4 Emissions Data Analysis ................................................................................. 3-13

3.5 Emission Factor Development ........................................................................ 3-21

4. MARINE VESSEL CLASSIFICATIONS AND POWER RATINGS ...................... 4-1

4.1 Classifications Employed in Literature ........................................................... 4-1

4.2 Operating Mode Classifications in Literature ................................................. 4-4

4.3 Analysis of Ship Type and Weight Categories ............................................... 4-6

5. EMISSION FACTOR SUMMARY ........................................................................... 5-1

6. REFERENCES ........................................................................................................... 6-1

APPENDIX A EMISSION FACTOR REGRESSION SUMMARIES .......................... A-1

APPENDIX B SUMMARY OF REPORTS REVIEWED ............................................. B-1

APPENDIX C ACUREX CLASSIFICATION OF SHIPTYPES .................................. C-1
ii

LIST OF TABLES

Page

Table 2-1. Summary of Emissions Data ........................................................................... 2-4

Table 3-1. Overview of the Lloyd’s Emission Test Database .......................................... 3-3

Table 3-2. Lloyd’s NO to NOx Ratio for Marine Engines ................................................ 3-5

Table 3-3. Overview of the USCG Emission Test Database ............................................ 3-8

Table 3-4. Lloyd’s Marine Engine Fuel Specifications .................................................... 3-10

Table 3-5. Marine Engine Emission Factor Algorithms ................................................... 3-44

Table 3-6. Marine Gas Turbine Emission Rate Data ........................................................ 3-52

Table 4-1. Booz-Allen Classification of Vessels .............................................................. 4-2

Table 4-2. Engine Loads by Ship Type for Each Operating Mode .................................. 4-7

Table 4-3. Results of Regressions between Horsepower and Deadweight Tonnage ........ 4-9

Table 4-4. Regressions of Horsepower vs. Deadweight and Cruise Speed ...................... 4-10

Table 4-5. Recommended Ship Types and Regressions of Horsepower

to Deadweight .................................................................................................. 4-11

Table 4-6. Suggested Loads by Mode .............................................................................. 4-13

Table 5-1. Marine Engine Emission Factor and Fuel Consumption Algorithms ............. 5-3

Table 5-2. Suggested Load Factors ................................................................................... 5-6
iii

LIST OF FIGURES

Page

Figure 3-1. Derivation of USCG Fuel H to C Ratio ....................................................... 3-9

Figure 3-2. Implied A/F Ratio ......................................................................................... 3-14

Figure 3-3. A/F Ratio Comparison - Detailed Carbon Balance ...................................... 3-17

Figure 3-4. A/F Ratio Comparison - Detailed Oxygen Balance ..................................... 3-18

Figure 3-5. A/F Ratio Comparison – Excess Air Balance .............................................. 3-19

Figure 3-6. CO2/O2 Relationship .................................................................................... 3-20

Figure 3-7. Consistency of A/F Ratio Estimates ............................................................. 3-22

Figure 3-8. Test Data Load Coverage ............................................................................. 3-23

Figure 3-9. Measured CO2 .............................................................................................. 3-25

Figure 3-10. Measured O2 ................................................................................................. 3-26

Figure 3-11. Measured NO ............................................................................................... 3-27

Figure 3-12. Measured CO ................................................................................................ 3-28

Figure 3-13. Measured HC ................................................................................................ 3-29

Figure 3-14. Measured SO2 ............................................................................................... 3-30

Figure 3-15. Measured PM ............................................................................................... 3-31

Figure 3-16. Fuel Consumption Data by Absolute Load .................................................. 3-32

Figure 3-17. Fuel Consumption Data by Fractional Load ................................................ 3-33

Figure 3-18. PM Emission Rate Data ............................................................................... 3-35

Figure 3-19. NO Emission Rate Data ............................................................................... 3-36
iv

LIST OF FIGURES

(Continued)

Page

Figure 3-20. NOx Emission Rate Data .............................................................................. 3-37

Figure 3-21. NO2 Equivalent NOx Emission Rate Data .................................................... 3-38

Figure 3-22. SO2 Emission Rate Data ............................................................................... 3-39

Figure 3-23. CO Emission Rate Data ................................................................................ 3-40

Figure 3-24. CO2 Emission Rate Data .............................................................................. 3-41

Figure 3-25. O2 Emission Rate Data ................................................................................. 3-42

Figure 3-26. HC Emission Rate Data ................................................................................ 3-43

Figure 3-27. NO Emission Rate Data by Fuel Type ......................................................... 3-49

Figure 3-28. NOx Emission Rate Data by Fuel Type ........................................................ 3-50

Figure 3-29. NO2 Emission Rate Data by Fuel Type ........................................................ 3-51

Figure 3-30. Gas Turbine Emission Rates ........................................................................ 3-53

Figure A-1. PM Emission Rate Data by Engine Type ..................................................... A-17

Figure A-2. NO Emission Rate Data by Engine Type ..................................................... A-18

Figure A-3. NOx Emission Rate Data by Engine Type ................................................... A-19

Figure A-4. NO2 Emission Rate Data by Engine Type ................................................... A-20

Figure A-5. CO Emission Rate Data by Engine Type ..................................................... A-21

Figure A-6. CO2 Emission Rate Data by Engine Type .................................................... A-22

Figure A-7. O2 Emission Rate Data by Engine Type ...................................................... A-23

Figure A-8. HC Emission Rate Data by Engine Type ..................................................... A-24
v

LIST OF FIGURES

(Continued)

Page

Figure A-9. Dry Exhaust Emission Rate Data by Engine Type ...................................... A-25

Figure A-10. H2O Emissions Rate Data by Engine Type .................................................. A-26

Figure A-11. Wet Exhaust Emission Rate Data by Engine Type ...................................... A-27

Figure A-12. NO Emission Rate Data by Fuel Type ......................................................... A-28

Figure A-13. NOx Emission Rate Data by Fuel Type ........................................................ A-29

Figure A-14. NO2 Emission Rate Data by Fuel Type ........................................................ A-30

Figure A-15. CO Emission Rate Data by Fuel Type ......................................................... A-31

Figure A-16. CO2 Emission Rate Data by Fuel Type ........................................................ A-32

Figure A-17. O2 Emission Rate Data by Fuel Type ........................................................... A-33

Figure A-18. HC Emission Rate Data by Fuel Type ......................................................... A-34

Figure A-19. Dry Exhaust Emission Rate Data by Fuel Type ........................................... A-35

Figure A-20. H2O Emission Rate Data by Fuel Type ........................................................ A-36

Figure A-21. Wet Exhaust Emission Rate Data by Fuel Type .......................................... A-37

1-1

1. INTRODUCTION

The EPA is initiating a review of its guidance on developing emission inventories for

ocean-going and harbor vessels operating at port areas. The current methodology, as defined in

AP-42, is based on a three step calculation. The first step apportions the time spent by a vessel

in a port area to different operating modes. The second calculates fuel consumption in each

operating mode. The third step calculates emissions using fuel consumption specific emission

factors, which is how marine engine emission factors have been historically specified. All of

these calculations are by vessel type and class, with the type specifying whether the vessel is a

tanker, passenger liner, etc, and the class specifying either the weight or horsepower range.

The time-in-mode is a function of the particular port area geography and is not considered in this

report. The other factors used in the computation are examined, with particular focus on the

emission factor, for all pollutants of concern. One reason for a detailed reconsideration of the

emission factor is that a number of large marine diesels have been tested for emissions and their

tests result have become available in the last few years. In addition, both the EPA and ARB have

recently sponsored studies to calculate marine vessel emissions in the South Coast Air Basin and

in some areas of Region IX, so that there is a body of new research available to update emission

factors. Hence, the use of a larger and newer database on marine vessel emission is expected to

substantially improve the quality of the derived emission factors.

In this work assignment, the EPA did not require a literature review, but instead provided with

nine reports as the basis for this review. Due to the fact that data on emissions from gas turbines

were restricted to two engines, most of the analysis presented in this report pertains only to diesel

powered marine vessels and only an average emission rate for the gas turbines is presented.

Section 2 of this report presents the findings of our literature review of the nine reports provided

by EPA. Section 3 details our analysis of emissions data contained in reports, and the resultant

derivation of emission factors. Section 4 provides an analysis of vessel classifications and
1-2

horsepower to vessel weight relationships. Section 5 summarizes the resultant emission factors

by vessel type, and operating mode.
2-1

2. REVIEW OF RELEVANT DATA

2.1 INTRODUCTION

As noted, the U.S. EPA had identified nine reports in its work assignment for review. All of

these were obtained by EEA from EPA and reviewed to assess the usefulness for this study. The

reports can be classified into two groups of four reports. One group provides detailed tables on

actual emissions data. The second group of four reports are studies that utilize one or more of

the reports in the first group to estimate emission factors, and to estimate emission inventories

for marine vessels operating in a specific region, like the South Coast Air Basin. One report

simply provided data on gas turbines emissions and is not reviewed in this section, but the data is

presented in Section 3.

The reports were reviewed to estimate the applicability of the data or the analysis to the EPA

requirements to calculate emission factors by ship class, type and operating mode. EPA has also

proposed rules for controlling marine engine emissions by defining three engine categories. The

EPA categories are based on individual cylinder displacement and the categories are:

• less than five liters;

• five to 20 liters; and

• greater than 20 liters.

These categories approximately correspond to engines in the high speed, medium speed and slow

speed categories used by IMO and Lloyds in previous analyses. However, the correspondence

may or may not hold true for some specific engine designs.

2.2 FINDINGS ON REPORTS PROVIDING EMISSIONS DATA

The four reports that provide emissions data includes one from British Columbia Ferry

Corporation, one from Environment Canada, one from Lloyd’s (in three sections), and one from

the U.S. Coast Guard. Each report is summarized in Appendix B.
2-2

The Lloyd’s data1,2,3 is the most detailed although there are some inconsistencies in the data. For

example, the text and table do not agree on the actual number of engines tested, or the type. Data

on engine tests are reported in Appendices, but engine make and displacement are not reported.

In addition, the Lloyd’s data also indicated large inconsistencies in the measured output at full

load versus actual engine ratings. Ostensibly, all engines were tested at idle, 25, 50, 75, and 100

percent of full power; yet in a majority of cases, the 100 percent rated power as measured on the

emissions test differs from the engine rated power by as much as ±50 percent. While reductions

in power associated with a service derating is possible and production variations of ±10 percent

may be reasonable, such large differences are cause for concern, especially as they are

unexplained in the text.

However, it should be noted that for most engines, full output corresponded to 83 ±17% of rated

power, while about ten engines have measured power either below 66 percent of rated or over

101 percent of rated power. Results indicate generally well behaved CO emission factors as a

function of percent of rated power but HC and NOx emissions dependence on load varies both in

magnitude and direction across engines as a function of load. In general, absolute emission rates

can vary across engines but the emissions profile for diesel engines as a function of load do not

vary greatly. The variations as plotted in the Lloyds report are so large across engines that it

raises questions on the data and test procedure.

The BC Ferry Test Program report5 appears incomplete and has several inconsistencies that

make the data difficult to use. The main issue is that the test procedure was conducted at two

different, undefined conditions labeled “normal cruise” and “docking operation”. Data on eight

engines are presented, (the tables show nine engine tested at normal cruise), but the test

conditions relative to the engine rated power are very inconsistent across engines. Engine data is

inadequate to determine what EPA category they may fall into. Data presented indicates that

five were medium speed diesels, while three are high speed engines (but the data on one high

speed engine shows an improbably high RPM figure for a 4500 kW diesel). Only fuel specific

emission rates are reported for the engines.
2-3

The Environment Canada report6 provides data on 11 engines tested on three modes:

maneuvering, low speed cruise and high speed cruise. The report does not describe how these

modes are defined and whether the relative load on the engine (or load factor) was similar across

the 11 engines. Only fuel specific emission indices are reported, and there are very large

variations across engines in a similar category. Not enough data is provided to determine how

these engines fit into the EPA categories. EEA attempted to obtain more detailed data on the test

procedure and measured emissions from Environment Canada, but could not do so in the time

available.

The tests conducted by the Coast Guard4 were on six ships with two engines each (one ship also

had two gas turbine engines in addition to the diesels). The test procedure was ostensibly

conducted at idle, 25, 50, 75, and 100 percent of maximum power, although here again, there

appear to be large differences in some instances between reported maximum power and engine

ratings. In one instance, the observed power is 85 percent higher than the engine rating

provided. Fuel specifications and engine type information (two-stroke/four-stroke) was not

provided.

Across all of the four reports, emissions data is available on 20 slow speed engine, 51 medium

speed engines and eight high speed engines, plus an additional ten auxiliary engines whose

characteristics are not listed. It is not clear if these have been any QA/QC on the data, since the

data appear to have certain inconsistencies.

Table 2-1 summarizes the data available and the test procedure used, to the extent it is

documented.

2.3 SUMMARY OF REPORTS ANALYZING EMISSIONS DATA

Of the four reports in this category, three were reports that developed marine emissions,

inventories for specific regions. The earliest (1991) report is by Booz-Allen and Hamilton9

 for

the ARB that developed inventories for Los Angeles/Long Beach and San Francisco. The report

computed emissions from Ocean-going, harbor, and fishing vessels. Ocean-going and harbor
2-4

TABLE 2-1

SUMMARY OF EMISSIONS DATA

Reference BC Ferries Environment

Canada

Lloyds

Register Coast Guard

Vessels 8 13 40 6

Engines

 - Slow speed 0 9 11 0

 - Medium speed 6 1 36 8

 - High speed 3 (?) 1 0 4

 - Auxiliary 3 5 2 0

Test Cycle • Normal

cruise

• Docking

• Full Power

for Auxiliary

• Maneuvering

• Low Speed

• Normal Cruise

• Hoteling for

Auxiliary

engines

• 100% load

• 75% load

• 50% load

• 25% load

• Idle

• 100% load

• 75% load

• 50% load

• 25% load

• Idle

Data Reported All except THC

in kg/ton of fuel

All in Kg/ton of

fuel

All except PM,

as raw data

All in mass per

kW-hr and per

ton of fuel

Potential

Problems

Test points

undefined and

varies by engine

Test points

undefined. All

engines not tested

at all loads

Measured

output at 100%

load unrelated

to rated power

Measured and

rated power do

not match for

some engines.
2-5

vessels were further divided into four types and five weight or HP classes. Fishing vessels were

subdivided into four HP categories. The operating profile in each port for the three vessel classes

was obtained by surveys. Emissions were calculated using the DOT Port Vessel Emission

Model, that calculates fuel consumption and resulting emissions using existing AP-42 emission

factors. The methodology is relatively simplistic in that emissions are purely a function of fuel

consumption, not load.

A very similar approach was used by Lloyds8 to determine emissions from ferries operated in

Vancouver by the British Columbia Ferry Corporation. The main difference appears to be the

use of engine specific emission factors derived from the Lloyds’s test program referenced in the

previous section. The report is not clear how fuel consumption was translated to emissions, i.e.,

by mode or based on aggregate fuel consumption rates.

The two other reports, by Arcadis (previously Acurex), calculate emission inventories for marine

vessels in the South Coast Air Basin. The 1996 report for the South Coast AQMD10 differed

from the 1991 Booz-Allen Report by including Navy and Coast Guard operations. The Acurex

report also used actual data on the HP ratings and fuel consumption (obtained from Lloyds) and

improved the characterization of operations in the South Coast. The Acurex report includes a

very detailed classification of eight ship types, with each ship type subdivided into eight to ten

weight categories. However emissions characterization again appear to be based on calculated

fuel consumption, with the use of emission factors on a unit of fuel consumed as derived by

Lloyds. These emissions appear to have been derived to represent a power setting of about 85

percent of maximum continuous rating (MCR), but there is no documentation of the

methodology used.

The more recent (1999) report by Arcadis (Acurex) for EPA Region IX8

 provides an analysis of

marine NOx emissions for the South Coast. The characterization of ship types is quite detailed as

in the 1996 report. This is the only report where emissions in units of work (g/kW-hr) were

derived as a function of percent of MCR. The emission factors on this basis were constructed

from the ‘raw’ data provided by Lloyds. Surprisingly, the report does not mention the large
2-6

discrepancy between rated and measured power and it is not obvious how the percent of MCR

was derived. Regression analysis of individual data points was utilized to relate NOx emissions

to engine load factor (% of MCR). The regression analysis, however, suggested that NOx

emissions either decline slightly or are independent of MCR. If these results are correct, it would

suggest little or no difference if NOx was treated as a constant or as a function of load.

Nevertheless, the methodology is conceptually superior to using aggregate fuel consumption data

that is multiplied by an emission factor in units of fuel consumption.

2.4 RECOMMENDATIONS FOR ANALYSIS

The review of the emission data available indicated significant inconsistencies in engine power

ratings versus measured power output that are too large to ascribe to engine-to-engine variability,

or a ‘service’ derating. Moreover, the test procedures used by different organizations are

inconsistent, while the reported results are incompatible with the results from a recommended

IMO standard test cycles. In most cases, engine displacement is not available, so that the

relationship to EPA engine categories cannot be exactly determined (but could be approximated).

In addition, some reported changes in engine emissions with load are directionally inconsistent

across engines. Hence, the data analysis focused on data cleaning techniques to identify and

correct or reject data that are determined to be in error.

Reports by Booz-Allen, Acurex and Arcadis employ consistent classifications by ship type, but

the Acurex and Arcadis reports have developed more detailed breakouts of each ship type by

weight category. The use of Lloyd’s data to determine the engine and auxiliary HP by these

detailed type and weight categories is an improvement over earlier techniques. If engine power

is linearly related to ship characteristics, it is not clear that models require the use of weight

categories for ship types. A linear regression connecting horsepower to ship weight is preferable

relative to analysis by weight categories.

The computation of emissions using fuel consumption as a surrogate load indicator appears to be

both unnecessary and to introduce errors. Indeed, the 1999 Arcadis report has utilized emissions

as a function of engine load factor to directly compute emission at every operating mode that is
2-7

represented in the operating profile. This direct method is preferable to linking emissions to fuel

consumption since the computation of fuel consumption and the translations to emissions

introduce multiplicative errors in emission estimations. EEA suggest a future marine emission

model with four specified modes of operation (e.g., docking, low speed cruise, etc.) where each

type of operation is associated with a single load factor. On the other hand, if emissions in

g/kW-hr are approximately constant with load factors, (as indicated for NOx in the Arcadis

report) different approaches may not lead to significantly different answers.

In addition, time constraints did not allow us to resolve many of the data issues raised. In the

future, EEA recommends that EPA focus on resolving some of the data issues and in expanding

the database.

3-1

3. EMISSION FACTOR DEVELOPMENT

3.1 INTRODUCTION

Ostensibly, six of the reports provided to EEA for review present the results of marine engine

emissions testing.1-6 However, three of these reports do not present the described emissions test

data in sufficient detail to support the fundamental analysis required for the development of

marine engine emission factors.3,5,6 These reports essentially present the results of the author’s

emission factor analysis, but not the underlying data that went into the analysis. Without this

underlying data, the utility of these reports is limited for several reasons. First, the presented

emission factors are expressed in units of emission mass per fuel mass consumed, a metric that

for real-world application requires either knowledge or estimation of fuel consumption rates.

However, fuel consumption rates are not usually measured, but rather estimated from engine

design and loading data, where engine loading itself can usually only be estimated. It seems

inappropriate to introduce additional uncertainty into the emissions estimation process through

the use of fuel mass-based emission factors in lieu of emission factors expressed in more

fundamental units of mass per unit engine work. Second, the presented emission factors

represent the aggregation of an unknown number of individual emission tests, such that the

statistical significance of the reported emission factors can be determined. Third, as

demonstrated below, considerable caution must be exercised in converting measured emission

concentrations into valid emission rates. Without access to the underlying test data, it is not

possible to either ensure that adequate caution has been exercised or that the generated emission

rates are comparable to those developed from other test programs.

Attempts were made to contact the authors of the three reports that do not present underlying

emission test data, but these attempts were not successful in the timeframe available to EEA for

analysis. As a result, the emission factors described below were developed through the statistical

analysis of fundamental test data presented in only three of the emission testing reports.1,2,4 Two

of these reports were prepared by Lloyd’s Register of Shipping and consider a wide range of

commercial engine sizes and configurations. The third report was prepared for the U.S. Coast
3-2

Guard (USCG) and considers a number of engines that are representative of marine engines in

use in the USCG fleet. As described below, all three datasets required considerable quality

assurance efforts to ensure that emission factors developed from the reported test data were both

reasonable and accurate.

3.2 LLOYD’S EMISSION TEST DATA

Lloyd’s Register of Shipping produced two reports that present the results of individual

commercial marine emission tests.1,2 Together, these reports present test data for a total of 46

main propulsion engines and 2 auxiliary engines as summarized in Table 3-1. Emission limits

for marine engines have historically been established by engine size expressed in terms of engine

rated speed, with nearly all commercial marine engines falling into the low and medium speed

categories. The Lloyd’s data are quite comprehensive, covering engines in both speed ranges,

and the test program reports provide a listing of nearly all critical test data parameters, including:

• raw concentration-based emission measurements for nitrogen oxide (NO), sulfur dioxide

(SO2), carbon monoxide (CO), carbon dioxide (CO2), oxygen (O2), and hydrocarbons

(HC),

• test engine load, speed, and volumetric fuel consumption,

• test engine specifications,

• test fuel density and carbon, hydrogen, nitrogen, and sulfur mass fractions, and

• ambient test conditions.

Nevertheless, it is important to recognize that exhaust mass flow rates are not measured, so the

conversion of measured emission concentrations to emissions mass must be based on theoretical

relationships. With the various parameters measured by Lloyd’s, it is possible to estimate

emissions mass (and thus mass emission rates) through the determination of the mass of intake

air required to produce the observed (i.e., measured) combustion products. Ignoring the potential

effects of exhaust non-homogeneity and emissions measurement error as well as the unaccounted

influences of non-measured combustion products (e.g., particulate matter (PM) and nitrogen

dioxide (NO2)), there is only one specific mass of intake air that will produce a given quantity of

combustion products for a given fuel. This specific mass can be calculated by chemically mass
3-3

TABLE 3-1

OVERVIEW OF THE LLOYD’S EMISSION TEST DATABASE

Ship Types

Tested

Number

of Ships

Tested

No. of

Main

Engines

Tested

No. of

Main

Engine

Tests

Average

Tests per

Main

Engine

No. of

Auxiliary

Engines

Tested

No. of

Auxiliary

Engine

Tests

Average

Tests per

Auxiliary

Engine

Bulk Carrier 6 6 37 6.2 0 0 0

Container 2 2 11 5.5 1 5 5.0

Dredger 6 6 32 5.3 0 0 0

Roll-on/Roll-off 9 16 90 5.6 1 5 5.0

Tug 7* 7 71 10.1 0 0 0

Tanker 9 9 58 6.4 0 0 0

Total Tests 39 46 299 6.5 2 10 5.0

* For tugs, testing was performed both with (38 tests) and without (33 tests) another vessel being

pushed. However, the net effect of this dual testing simply represents an increase in the number

of engine loading scenarios tested for tugs.

balancing the input fuel characteristics with measured emission products (both of which are

reported by Lloyd’s). Such an approach is analogous to the carbon balance technique employed

in motor vehicle emissions testing to estimate dilution air volumes in constant volume sampling

(CVS) systems.

Given a complete and accurate characterization of: (1) emissions, (2) fuel, and (3) intake air,

chemical mass balancing will produce an accurate determination of intake air mass. Ignoring

any measurement error, the Lloyd’s database does provide a complete characterization of the

combustion fuel. Characterization of major emission species (i.e., CO2 and O2) as well as

several minor emission species is also provided. While the widest possible scope of emission

measurements is desirable for increased precision, relatively accurate mass balancing can be

performed using emission measurements for CO2 and O2 alone, as these compounds account for

the bulk of exhaust carbon and oxygen. For marine engines for example, emissions of either are

one to two or more orders of magnitude higher than emissions of either CO or HC. However, no
3-4

measurements of intake air characteristics are provided by Lloyd’s. Intake air containing

significant concentrations of carbon or hydrogen can significantly influence chemical mass

balance accuracy. In the absence of specific intake air characteristics, it is typical to assume an

“average” air composition of 21 percent oxygen and 79 percent nitrogen (representing nitrogen

plus other minor, relatively inert, air constituents). Such a presumption was employed in all

mass balance analysis performed for this study.

Several additional issues should be considered in interpreting the Lloyd’s emissions test data

used in this study. No PM testing was performed and, therefore, the Lloyd’s data are of no value

in determining marine PM emission factors. Additionally, HC measurements are missing for 26

of the 309 emission tests performed. In instances where detailed chemical mass balancing, as

described below, included measured HC, a value of zero was assumed for these 26 tests. This

assumption is expected to result in only minor precision losses for calculated intake air mass as

most combustion hydrogen is emitted as water (H2O), not HC (emitted HC is typically two to

three orders of magnitude lower than emitted H2O). However, all 26 tests were excluded from

the statistical analysis underlying the determination of HC emission factors.

Oxides of nitrogen (NOx) emission factors are of particular interest in this study as NOx

represents a major pollutant emission species from diesel engines such as those used for marine

propulsion. However, the Lloyd’s database includes only NO measurements, omitting other NOx

components such as NO2. To estimate total NOx emissions from measured NO data, EEA relied

on supplementary data presented in the text portion of the Lloyd’s report1

 that summarized NO

to NOx ratios for a range of marine engine emission tests conducted prior to those reported.

These tests reportedly cover a diverse range of fuels and test conditions, but the observed NO to

NOx ratio, as presented in Table 3-2, varies over a relatively narrow range of 0.86 to 0.98, with a

mean and standard deviation of 0.94 and 0.03 respectively. Based on this data, EEA assumed for

the purpose of this study, that emitted NOx is equal to measured NO divided by 0.94.
3-5

TABLE 3-2

LLOYD’S NO TO NOx RATIO FOR MARINE ENGINES

Engine

Type

Test

Fuel Idle 25%Load

50%

Load

75%

Load

Rated

Load

Fuel 1 0.93 0.93 0.95 0.96 0.96

Fuel 2 0.96 0.89 0.91 0.93 0.93

Fuel 3 0.91 0.91 0.92 0.92 0.96

Propeller

Law

Fuel 4 0.86 0.87 0.89 0.92 0.94

Fuel 1 0.97 0.98 0.97 0.96

Fuel 2 0.92 0.93 0.92 0.93

Fuel 3 0.96 0.94 0.97 0.96

Constant

Speed

Fuel 4 0.95 0.94 0.94 0.94

Overall Average = 0.94, Standard Deviation = 0.03

Even though Lloyd’s reported ambient temperature, pressure, and humidity data, no ambient

corrections have been applied to any of the emission estimates presented in this study. The

decision to ignore ambient corrections was based on the fact that: (1) no generally accepted

correction algorithms have been developed for marine engines, (2) ambient data is not available

for the USCG data that were combined with the Lloyd’s data to generate emission factors (see

Section 3.3 below), and (3) the magnitude of ambient corrections are expected to be minor

relative to the overall variability of the emissions data.

All emissions data for one of the tankers tested by Lloyd’s (designated as ship TK7) have been

excluded from statistical emission factor analysis because exhaust O2 measurements are not

reported. Unlike HC, O2 is a major exhaust constituent and no reliable assumptions can be made

regarding intake air mass (and thus exhaust and emissions mass) in the absence of reliable O2

data. As a result, the seven emission tests conducted on tanker TK7 were excluded from the

analysis database.
3-6

All Lloyd’s test data not otherwise excluded as described above have been treated with equal

weight in the emission factor analysis conducted for this study. This may result in some bias of

analysis results toward engines with an above average number of associated emission tests, but

there is no obvious means of weighting the data that would ensure less bias than simply treating

all data with equal weight. Lloyd’s stated test program design criteria was to conduct testing at

idle and 25, 50, 75, and 100 percent of rated engine output. Therefore, ideally, each engine

would be tested five times at five distinct operating modes. However, as indicated in Table 3-1,

the number of actual tests per engine ranged from five to ten, with tug testing representing the

upper bound due to testing in both “pushing” and “non-pushing” modes.

Because all testing was performed at variable load conditions, applying a weighting factor to all

the test data for a given engine to equate that engine’s overall statistical influence to that of a

“five test” engine can result in an unintended bias at specific loads where the weighted engine’s

test data carries less influence than data from another engine, even though both represent equally

valid test measurements at the given load. An alternative approach of simply discarding all but

five test data points across the load range for any given test engine is less problematic, but

requires some methodology to select those data points to either retain or exclude. Given the

considerable variability in observed test data, it was concluded that the overall bias induced by

simply retaining all data points was likely to be minor and thus no specific data weighting or

selection/exclusion scheme was employed in this analysis. Follow-up analysis to quantify the

potential magnitude of any bias can be conducted, but is beyond the scope of this analysis.

3.3 U.S. COAST GUARD EMISSION TEST DATA

Environmental Transportation Consultants produced a report for the Volpe National

Transportation Systems Center and the USCG that presents the results of marine engine emission

tests on six USCG vessels.4

 In total, the report presents comprehensive test data for 12 main

diesel propulsion engines as summarized in Table 3-3. Summary data are also presented for two

additional gas turbine propulsion engines, but supporting detailed test data are omitted from the

report necessitating the exclusion of detailed gas turbine engine analysis from this study. In
3-7

general, the USCG data are less detailed that the Lloyd’s data described in Section 3.2 above, but

reported test data parameters include:

• raw concentration-based emission measurements for NOx, SO2, CO, CO2, O2, and HC,

• raw mass-based emission measurements for PM,

• test engine load, speed, and volumetric fuel consumption, and

• test engine specifications.

Data on fuel specifications, density, and composition was not included, representing the most

critical omission for purposes of this study. Data on ambient test conditions was also omitted,

but this omission is a lesser concern as any ambient adjustments to emissions are expected to be

minor relative to overall data variability.

As described in Section 3.2, fuel characteristics are a necessary element in constructing an

accurate chemical mass balance as required to estimate intake air mass and subsequently exhaust

and emissions mass. Unfortunately, the USCG test data report only describes the combustion

fuel as “diesel” and presents no supporting test data. Therefore, EEA undertook an alternative

analysis approach in an attempt to estimate the characteristics of the unknown USCG diesel

“fuel” as follows.

Using reported O2 and CO2 emission concentrations, the stoichiometric CO2 concentration for

the USCG fuel was derived through regression analysis as summarized in Figure 3-1. The

derived stoichiometric CO2 concentration (15.2 percent at zero percent O2) can readily be

translated through chemical mass balance to an implied fuel hydrogen to fuel carbon (H to C)

ratio of 1.9127. Such a ratio is not typical for a diesel fuel, instead being more reflective of a

lighter fuel such as gasoline and implying a bias toward a slight under-measurement of CO2, O2,

or both. Although diesel fuels with H to C ratios above 1.9 have been reported, they generally

represent upper bound H to C fuels and would be quite uncommon as an average fuel

 



 Certainly USCG test fuel specifications varied across test engines. However, fuel specifications can only be

inferred from the aggregate USCG data and, therefore, derived specifications represent average, rather than

specific fuel characteristics.
3-8

TABLE 3-3

OVERVIEW OF THE USCG EMISSION TEST DATABASE

Ship Types

Tested

Number

of Ships

Tested

No. of

Main

Engines

Tested

No. of

Main

Engine

Tests

Average

Tests per

Main

Engine

No. of

Auxiliary

Engines

Tested

High Endurance Cutter (WHEC) 1 2* 30 15.0 0

Medium Endurance Cutter (WHEC) 2 4 60 15.0 0

Patrol Boat (WPB) 2 4 52 13.0 0

Utility Boat (UTB) 1 2 30 15.0 0

Total Tests 6 12* 172 14.3 0

* The report actually presents summary results for 2 WHEC diesel propulsion engines and 2

WHEC gas turbine propulsion engines, but only includes detailed test data for the two diesel

engines. This “missing” data required that the two gas turbine engines be excluded from

detailed statistical emission factor analysis in this study.

characteristic over the entire USCG emissions testing program. As a result, EEA elected to

utilize the average fuel specifications for the various “diesel” fuels included in the Lloyd’s

marine engine test program as a better means of approximating the average unknown fuel

characteristics associated with the USCG data. Table 3-4 presents the statistical specifications of

the various Lloyd’s test fuels. The average “all fuels” specifications were used for all USCG

chemical mass balance analysis in this study.

Like the Lloyd’s data, several additional assumptions are required in processing the USCG

database. In general, however, required assumptions for the USCG data are more extensive than

those associated with processing the Lloyd’s database, but inclusion of the USCG data in this

study is considered to be critical for two primary reasons. First, the USCG data serves as the

only independent means of validating the basic trends observed through the Lloyd’s test data.

Second, the USCG database is the only database provided to EEA for review that includes PM
FIGURE 3-1

Derivation of USCG Fuel H to C Ratio

05

10152025

0 2 4 6 8 10 12 14 

CO2 (percent dry)

O2 (percent dry)

O2 = 20.956 - 1.375 (CO2

(t=353) (t=-135) 

r

2 = 0.99, F = 18264, Obs = 142

Stoichiometric CO2 = 15.24

Implied Fuel H to C Ratio = 1

3-9
3-10

TABLE 3-4

LLOYD’S MARINE ENGINE FUEL SPECIFICATIONS

Parameter Gas Oil Heavy

Fuel Oil

Intermediate

Fuel Oil

Light

Fuel Oil All Fuels

Number of Observations 25 9 2 19 55

Average 0.8553 0.9816 0.9900 0.9539 0.9149

Density Standard Deviation 0.0056 0.0055 0.0000 0.0297 0.0587

Average 0.8651 0.8606 0.8580 0.8601 0.8624

Carbon Content

Standard Deviation 0.0032 0.0078 0.0004 0.0047 0.0052

Average 0.1293 0.1080 0.1042 0.1150 0.1200

Hydrogen Content Standard Deviation 0.0030 0.0024 0.0001 0.0075 0.0103

Average 0.0020 0.0040 0.0019 0.0033 0.0028

Nitrogen Content Standard Deviation 0.0021 0.0024 0.0003 0.0005 0.0019

Average 0.0036 0.0274 0.0358 0.0215 0.0149

Sulfur Content

Standard Deviation 0.0021 0.0077 0.0002 0.0094 0.0125

Average 1.7812 1.4954 1.4477 1.5937 1.6576

H to C Ratio

Standard Deviation 0.0468 0.0338 0.0010 0.1029 0.1385

Average 0.0020 0.0040 0.0019 0.0033 0.0028

N to C Ratio

Standard Deviation 0.0020 0.0024 0.0003 0.0005 0.0019

Average 0.0016 0.0120 0.0156 0.0094 0.0065

S to C Ratio

Standard Deviation 0.0009 0.0034 0.0001 0.0041 0.0055

data. Nevertheless, the following issues should be considered in evaluating the USCG marine

emissions data analysis.

Many of the HC measurements included in the USCG database are questionable and five of the

172 tests are missing HC measurements altogether. Additionally, about 17 percent of the

reported HC measurements indicate concentrations below 0.001 ppmC, while nearly all of the

remaining 83 percent exhibit concentrations over four orders of magnitude higher (often for the

same engine at the same test conditions). For purposes of this analysis, these concentrations

were assumed to equal 0.001 ppmC, but more in depth follow-up analysis beyond the scope of
3-11

this study may yield sufficient information to exclude these data as erroneous. As was the case

with the Lloyd’s data, in instances where detailed chemical mass balancing, as described below,

included measured HC, a value of zero was assumed for all five tests where HC was unreported.

This assumption will result in only minor precision losses for calculated intake air mass as most

combustion hydrogen is emitted as H2O, not HC. As with the Lloyd’s data, all five tests were

excluded from the statistical analysis underlying the determination of HC emission factors. At

the same time, all HC measurements reported as being below 0.001 ppmC were retained

throughout the entire analysis and could serve as a downward bias on estimated HC emission

factors should such measurements ultimately be identified as erroneous.

USCG HC measurements were assumed to be reported as dry since they were based on bag

sampling at a point apparently downstream of a sample line water trap. Since Lloyd’s HC

measurements are report as wet, a conversion factor was applied to the USCG HC data to

convert the reported data to a wet measurement equivalent. This conversion factor was derived

from analysis of the Lloyd’s test data, through which it was determined that the average wet to

dry exhaust concentration ratio was 0.9658, with a standard deviation of 0.0158 (based on 1215

data points associated with 302 individual test records evaluated over four mass balance

techniques plus 7 individual test records evaluated over a single mass balance technique).

In an analogous fashion, the USCG data reports NOx while the Lloyd’s data reports NO as a NOx

surrogate. As described in Section 3.2, Lloyd’s claims an average NO to NOx ratio of 0.94, a

factor used by EEA to convert Lloyd’s NO data to a NOx equivalent. This same factor was also

used to convert USCG reported NOx data to an NO equivalent.

Unlike the Lloyd’s data, which was treated without weighting individual data points, the USCG

data was aggregated before statistical processing. This aggregation was necessary to address the

fact that USCG data was reported individually for each of up to three tests performed on the

same engine at the same load conditions. In effect, multiple data points were reported for

identical test conditions, creating an inherent weighting factor of up to three for the USCG data

versus the Lloyd’s data. To reduce the weight of the USCG data to unity, all data points
3-12

applying to identical test conditions were collapsed into a single data point representative of the

average reported test results for the component data.

Such an approach is generally consistent with the “average” test results for each unique set of

test conditions as reported in the USCG test document.4

 Nevertheless, the USCG reported

average test results will vary in some circumstances from those used in this study. This results

from the fact that the average test results presented in the USCG report include the effects of

partial tests, whereas those used in this study do not. For example, in the USCG report, results

for three tests, two of which include measurement of HC, CO, NOx, SO2, O2, CO2, and PM and

one of which only includes measurement of HC are averaged over two tests for CO, NOx, SO2,

O2, CO2, and PM and over three tests for HC. In this study, all species are averaged over only

the two comprehensive tests and the third, HC-only test is ignored. This is deemed a more

appropriate aggregation methodology since there is no way of knowing how unmeasured

emission species will have varied over the third test in accordance within any observed variation

in HC. In addition, any individual tests for which inconsistent air/fuel ratios were calculated

across the differing estimation methodologies described in Section 3.4 below, were also excluded

from the aggregation process.

Finally, the USCG report also included specific fuel consumption estimates only for the average

engine speed and output calculated for each unique set of test conditions. Since individual test

results were re-aggregated for this study in accordance with the modified “acceptance” criteria

described above, it was necessary to estimate fuel consumption for each individual test, instead

of simply knowing the aggregate test average. In the absence of specific engine maps, EEA

employed a simplifying assumption that fuel consumption varies linearly with engine speed for

outputs “near” the specific engine output for which the USCG reported fuel consumption.

Observed engine speed variations ranged from only –3 to +4 percent of reported average engine

speed so that calculated fuel consumption adjustments averaged only 0.01 percent, with a

maximum adjustment of 1.1 percent.
3-13

3.4 EMISSIONS DATA ANALYSIS

As described above, exhaust mass is not a measured component of either the Lloyd’s or USCG

databases. Nevertheless, an estimate of exhaust mass is necessary to covert concentration-based

emission measurements into mass-based equivalents. To estimate exhaust flow for each

emissions test included in the combined Lloyd’s/USCG database, a chemical mass balance was

employed using intake fuel characteristics and measured exhaust components to estimate the

effective combustion air/fuel (A/F) ratio. This A/F ratio estimate can then be combined with fuel

flow measurements reported for each emissions test to derive an estimate for intake air mass, that

when added to intake fuel mass results in the required estimate of exhaust mass. In referring to

intake air, it is worth noting that this includes both intake and scavenge air (as applicable,

typically for two stroke engines) and that the estimated A/F ratio is the effective mass ratio of all

air (regardless of the timing or location of its injection into the flow stream) to combustion fuel.

While it is not possible to separate actual intake air from scavenge air based on exhaust

measurements alone, such a separation is not required to estimate total exhaust mass, which is

the critical analysis parameter for this study.

Figure 3-2 presents a summary of the A/F ratios calculated on the basis of Lloyd’s and USCG

reported exhaust components. Based on the calculated ratios, EEA has some concern over the

integrity of the reported emissions data. This concern stems primarily from the magnitudes of

the calculated A/F ratios over the entire engine load range, defined by EEA as the “fractional

load” or the ratio of the reported engine output during the emissions test to the reported rated

engine output. Even at 100 percent rated load, the Lloyd’s database generally implies A/F ratios

between 30:1 and 40:1. This is substantially higher than the 20:1 or so A/F ratios that would be

expected from previous experience with on-road diesel engines. Moreover, while calculated A/F

ratios approaching 80:1 are not unexpected at low load ranges, values of 1000:1 or, in one case,

4000:1 are certainly cause for concern. As noted above, scavenge airflow for two stroke engines

could explain some of the excessive A/F ratios, but the generally apparent over-prediction is

observed for both two and four stroke engines. Since EEA has no information on the number of

engines employing secondary air scavenging or the mass of air flow associated with such
FIGURE 3-2

Implied A/F Ratio

10

100

1000

10000

0% 20% 40% 60% 80% 100% 

Fractional Load

A/F - Simple Carbon Balance

Lloyds (Consistent A/F)USCG (Consistent A/F)Lloyds (Inconsistent A/FUSCG (Inconsistent A/F

3-14
3-15

systems on marine engines, it is not possible to elaborate further (for this study) as to the role

that secondary scavenging systems may have on apparent A/F ratio over-prediction.

In an attempt to isolate those data that are most highly suspect, EEA undertook a series of

alternative chemical mass balance approaches to estimating effective A/F ratio. The first

approach, designated for this study as the simple carbon balance approach, estimates A/F ratio on

the basis of fuel H to C ratio and exhaust O2 to CO2 ratio alone. Without presenting the detailed

mass balance derivation here, this method presumes that all intake fuel and air is fully

represented in the exhaust as CO2, H2O, and unreacted air (represented as 21 percent O2 and 79

percent molecular nitrogen (N2)). Furthermore, this method represents a commonly employed

mass balance approach in that it accounts for major exhaust constituents, providing a reasonably

reliable A/F ratio estimate. However, in instances where exhaust constituents may not be

measured accurately, there are more detailed alternative chemical mass balance methods that can

be employed for validation purposes.

A more detailed carbon balance approach considers all measured exhaust constituents that

contain either carbon or hydrogen (HC, CO, and CO2 in the database available for this study).

This approach can provide a considerably more accurate A/F ratio estimate when significant

concentrations of either CO or HC are measured. A third A/F ratio estimation approach

employing a detailed oxygen (rather than carbon) balance considers all measured oxygen,

nitrogen, and hydrogen containing exhaust species (CO, CO2, O2, NO, SO2, and HC in the

database available for this study). Finally, a fourth A/F ratio estimation approach based solely

on the amount of intake air required to completely combust the intake fuel and provide the

measured quantity of “excess air” in the exhaust was also employed. This excess air approach

uses only measured exhaust oxygen and measured fuel characteristics to satisfy the required

chemical mass balance criteria.

Figures 3-3 through 3-5 present the results of the alternative A/F ratio evaluations. The three

figures each present a plot of the estimated A/F ratio for one of the three alternative mass balance

methods employed in this study versus the A/F ratio estimated using the simple carbon balance
3-16

approach. The considerable variation between three of the four approaches is easily observed.

As might be expected, the simple carbon balance and detailed carbon balance approaches

produce similar A/F estimates since both principally rely on a balance of intake and exhaust

carbon. The excess air approach, which relies on the major exhaust oxygen containing

component (i.e., air) as its primary mass balance criteria indicates significant deviation from the

carbon-based approaches, but the greatest deviation is observed for the detailed oxygen balance,

which relies on all exhaust oxygen containing compounds as its mass balance criteria.

Moreover, the disagreement between the four approaches gets more pronounced as the estimated

A/F ratio increases, with the oxygen-based approaches generally estimating lower A/F ratios

than the carbon-based approaches. Given that exhaust mass and thus emissions mass are directly

dependent on A/F ratio, there are clear concerns associated with the raw exhaust measurements

reported in the marine engine database employed in this study.

Further evidence of the potential problems with the marine engine emissions databases can be

observed by comparing measured CO2 and O2 concentrations. Figure 3-6 presents such a

comparison, where the dashed lines represent the theoretical relationship between measured CO2

and O2 as implied by the measured characteristics of the Lloyd’s test fuels. Deviations from

these theoretical relationships are indicative of instances in which measurement error for either

CO2, O2, or both are likely. Clearly, such deviations are quite common at low CO2

concentrations, which correspond to high O2 and thus high A/F ratios. More troubling, however,

is the fact that significant deviations are observed across the full measured CO2 spectrum.

Given the concerns associated with the reported exhaust emissions data, it would be

advantageous to perform a more in depth analysis of the test programs underlying the reported

data. However, such an analysis is beyond the scope of this study. As an alternative, EEA

quantified the magnitude of the variation between the alternative A/F ratio estimation

methodologies and retained for statistical analysis, only those tests for which consistent A/F

ratios were observed across the alternative estimation approaches. For this study, consistent A/F

ratios were defined as instances in which: (1) three of the four employed A/F ratio estimation
FIGURE 3-3

A/F Ratio Comparison

10

100

1000

10000

10 100 1000 

A/F - Simple Carbon Balance

A/F - Detailed Carbon Balance

Lloyds (Consistent A/F)USCG (Consistent A/F)Lloyds (Inconsistent A/F)USCG (Inconsistent A/F)One-to-One Line

3-17
FIGURE 3-4

A/F Ratio Comparison

10

100

1000

10000

10 100 1000 

A/F - Simple Carbon Balance

A/F - Detailed Oxygen Balance

Lloyds (Consistent A/F)USCG (Consistent A/F)Lloyds (Inconsistent A/F)USCG (Inconsistent A/F)One-to-One Line

3-18
FIGURE 3-5

A/F Ratio Comparison

10

100

1000

10000

10 100 1000 

A/F - Simple Carbon Balance

A/F - Excess Air Balance

Lloyds (Consistent A/F)USCG (Consistent A/F)Lloyds (Inconsistent A/F)USCG (Inconsistent A/F)One-to-One Line

3-19
FIGURE 3-6

CO2 / O2 Relationship

05

10152025

0 2 4 6 8 10 12 14 

Measured CO2 (percent dry)

Measured O

2 (percent dry) Lloyds (Consi

USCG (ConsisLloyds (InconUSCG (Incons

3-20
3-21

methodologies produced cumulative absolute estimate deviations of no more than 15 percent

relative to the estimate produced by the simple carbon balance approach and (2) none of the three

otherwise consistent A/F ratio estimates varied by more than 10 percent from the estimate

produced by the simple carbon balance approach. The choice of these retention criteria are

somewhat arbitrary, but deviations of this magnitude yield reasonably consistent mass emissions

estimates, well within the overall uncertainty of the underlying test programs.

All figures presented in this section allow inspection of both consistent and inconsistent A/F ratio

test data. Mass emission estimates presented in these figures and used for subsequent emission

factor analysis represent the arithmetic average of the mass emission rates associated with the

three most consistent A/F ratio estimation methodologies: the simple carbon balance, the detailed

carbon balance, and the excess air approaches. Figure 3-7 presents a distribution of the

cumulative absolute deviations associated with these same three A/F ratio estimation approaches

for the combined Lloyd’s and USCG database. As can be noted, approximately 18 percent of all

reported emission tests do not meet the consistent A/F ratio criteria. Such records are excluded

from all emission factor analysis in this study but have been included on all figures to allow the

reader to evaluate the potential impact associated with this exclusion.

3.5 EMISSION FACTOR DEVELOPMENT

Based on the database development and acceptance criteria presented in the preceding sections,

EEA compiled an overall emission factor analysis database consisting of 291 “consistent A/F

ratio” emission tests spanning the full range of engine operating loads (i.e., from idle to 100

percent rated output). Figure 3-8 summarizes the overall test engine and operating loads

represented in this database. As indicated, the bulk of the large engines tested by Lloyd’s fail to

meet the A/F ratio acceptance criteria, so that the overall database includes only a modest

number of tests on engines rated above 10,000 kilowatts (kW). Given the under-representation

of large marine engines in this database, further investigation of large engine performance

relative to both emissions measurement accuracy and consistency with the emission factor

algorithms presented below is recommended.
FIGURE 3-7

Consistency of A/F Ratio Estimates

0.000.050.100.150.200.250.300.35

Fraction of Data in Range

Cumulative Absolute A/F Ratio Maximum A/F Ratio Deviation

0-1% 1-3% 3-5% 5-10% 10-15% 15-20% 20-25% 

3-22
FIGURE 3-8

Test Data Load Coverage

0

5000

10000150002000025000

0 5000 10000 15000 20000 

Test Load (kW)

Rated Load (kW) Lloyds (Consistent A/F

USCG (Consistent A/F)Lloyds (Inconsistent A/USCG (Inconsistent A/

3-23
3-24

Figures 3-9 through 3-15 present measured (i.e., concentration-based) emissions by fractional

engine load for each of the emission species represented in the analysis database. Although

overall measurements for most species span several orders of magnitude, clear trends are

observable for all species except CO, HC, and SO2. The lack of a distinguishable trend in the

raw CO and HC data is likely the result of the relatively low production of both species across

the entire load range of diesel engines. The lack of a load-based trend for SO2 is due to the direct

relationship of SO2 emissions to fuel sulfur content, which varies considerably across the

emission test database.

Figures 3-16 and 3-17 present reported fuel consumption by absolute and fractional test load

respectively. As indicated, the distribution of reported fuel consumption over fractional load

space is quite “well behaved.” Regression analysis indicates that fuel consumption is inversely

related to fractional engine load as follows:

Fuel Consumption (g/kW-hr) = 14.1205 (1/Fractional Load) + 205.7169

(t = 22.75) (t = 32.88)

[r2

 = 0.64, F = 518, Observations = 291]

Based on this behavior, along with the previously illustrated (see Figure 3-2) well defined

behavior of A/F ratio (and thus exhaust mass) with fractional load, statistical regression

structures based on emissions mass by fractional load were investigated as the most promising

basis for emission factor algorithms. It is worth noting that previous studies have investigated

emission mass in terms of fuel consumption alone and while such an approach may yield

reasonable emission estimates, fuel consumption is itself dependent on fractional load as

illustrated in Figure 3-17 and, therefore, is not an appropriate independent regression parameter

in instances where fuel consumption is not measured directly (with the exception of SO2

emissions, which are directly dependent on highly variable fuel sulfur content). While a two step

conversion from fractional load to fuel consumption to emissions mass is certainly feasible, the

combined uncertainty associated with such a process is surely larger than the single step

estimation of emissions mass from a given fractional load.
FIGURE 3-9

Measured CO2

0.010.101.00

10.00

0% 20% 40% 60% 80% 100% 

Fractional Load

CO

2 (volume percent dry) Lloyds (Consistent A/F)

USCG (Consistent A/F)Lloyds (Inconsistent A/FUSCG (Inconsistent A/F

3-25
FIGURE 3-10

Measured O2

1

10

100

0% 20% 40% 60% 80% 100% 

Fractional Load

O

2 (volume percent dry)

Lloyds (Consistent A/F)USCG (Consistent A/F)Lloyds (Inconsistent A/FUSCG (Inconsistent A/F

3-26
FIGURE 3-11

Measured NO

10

100

1000

10000

0% 20% 40% 60% 80% 100% 

Fractional Load

NO (ppmVd)

Lloyds (Consistent A/F)USCG (Consistent A/F)Lloyds (Inconsistent A/FUSCG (Inconsistent A/F)

3-27
FIGURE 3-12

Measured CO

1

10

100

1000

10000

0% 20% 40% 60% 80% 100% 

Fractional Load

CO (ppmVd)

Lloyds (Consistent A/F) USCG (Consistent ALloyds (Inconsistent A/F) USCG (Inconsistent 

3-28
FIGURE 3-13

Measured HC

0.11.0

10.0

100.0

1000.0

0% 20% 40% 60% 80% 100% 

Fractional Load

HC (ppmCVw)

Lloyds (Consistent A/FUSCG (Consistent A/F)Lloyds (Inconsistent A/USCG (Inconsistent A/F

3-29
FIGURE 3-14

Measured SO2

1

10

100

1000

10000

0% 20% 40% 60% 80% 100% 

Fractional Load

SO

2 (ppmVd)

Lloyds (Consistent A/F) USCG (Consistent ALloyds (Inconsistent A/F) USCG (Inconsistent 

3-30
FIGURE 3-15

Measured PM

0.11.0

10.0

0% 20% 40% 60% 80% 100% 

Fractional Load

PM (lb per hour)

Lloyds (Consistent A/F)USCG (Consistent A/F)Lloyds (Inconsistent A/F)USCG (Inconsistent A/F)

3-31
FIGURE 3-16

Fuel Consumption Data by Absolute Load

10

100

1000

10000

10 100 1000 10000 

Test Load (kW)

Fuel Consumption (g/kW-hr)

Lloyds (Consistent A/F)USCG (Consistent A/F)Lloyds (Inconsistent A/FUSCG (Inconsistent A/F

3-32
FIGURE 3-17

Fuel Consumption Data by Fractional Load

10

100

1000

10000

0% 20% 40% 60% 80% 100% 

Fractional Load

Fuel Consumption (g/kW-hr)

Lloyds (Consistent A/FUSCG (Consistent A/FLloyds (Inconsistent AUSCG (Inconsistent A/Consistent Data Regres

3-33
3-34

Figures 3-18 through 3-26 summarize work-specific mass emission rates by species based on the

chemical mass balance of parameters reported in the combined Lloyd’s and USCG database. In

general, all species display an inverse exponential distribution with fractional load. Although the

behavior of the work-specific emission rate data is at least as good as expected given the wide

range of engines tested, an expected upturn in the work-specific emission rate for NOx at high

fractional loads is not readily apparent. Nevertheless, to check for the potential existence of such

a trend, both full and partial load range regression structures were evaluated.

To confirm the validity of an inverse exponential relationship between mass emissions and

fractional load as opposed to a simple linear relation, EEA regressed the emissions/load data

over both linear and inverse exponential structures. In all cases, excepting SO2 as discussed

below, the inverse exponential relations exhibited substantially better statistics (i.e., higher

correlation coefficients and more significant regression parameter statistics). Restricted load

range regressions evaluated to determine whether the inverse exponential relations were most

appropriate over the entire fractional load range or whether specific fractional load ranges were

better represented with alternative linear algorithms, revealed similar results. Specifically,

separate regressions over the 0-20 percent and 20-100 percent fractional load ranges were

constructed to determine if a better inverse exponential fit over the lower load range or an

alternative linear fit over the upper load range might be more appropriate than an inverse

exponential fit over the full fractional load range. For all emission species (again excepting

SO2), it was evident that the best statistical fit of the reported emissions data was obtained with

the inverse exponential relations over the full fractional load range. In no case did any linear

relation over the full or upper load range (20-100 percent) yield better statistics. After

determining the superiority of the inverse exponential approach, the most appropriate values for

the fractional load exponents were evaluated, although all regressions yielded surprisingly good

fits for an initially evaluated exponent of negative unity. Alternative exponent value regressions

were selected as the basis for the best fit regression only in cases where such values produced

significantly improved statistics relative to a unity exponent. Table 3-5 presents the results of

this regression analysis for each emission species evaluated.
FIGURE 3-18

PM Emission Rate Data

0.11.0

10.0

100.0

0% 20% 40% 60% 80% 100% 

Fractional Load

PM (g/kW-hr)

Lloyds (Consistent A/F)USCG (Consistent A/F)Lloyds (Inconsistent A/F)USCG (Inconsistent A/F)Consistent Data Regression L

3-35
FIGURE 3-19

NO Emission Rate Data

1

10

100

1000

0% 20% 40% 60% 80% 100% 

Fractional Load

NO (g/kW-hr)

Lloyds (Consistent A/F)USCG (Consistent A/F)Lloyds (Inconsistent A/F)USCG (Inconsistent A/F)Consistent Data Regression 

3-36
FIGURE 3-20

NOx Emission Rate Data

1

10

100

1000

0% 20% 40% 60% 80% 100% 

Fractional Load

NO

x (g/kW-hr)

Lloyds (Consistent A/F)USCG (Consistent A/F)Lloyds (Inconsistent A/F)USCG (Inconsistent A/F)Consistent Data Regression L

3-37
FIGURE 3-21

NO2 Equivalent NOx Emission Rate Data

1

10

100

1000

0% 20% 40% 60% 80% 100% 

Fractional Load

NO

2 (g/kW-hr)

Lloyds (Consistent A/F)USCG (Consistent A/F)Lloyds (Inconsistent A/F)USCG (Inconsistent A/F)Consistent Data Regression 

3-38
FIGURE 3-22

SO2 Emission Rate Data

0

1020304050607080

0 5 10 15 20 25 

Fuel Sulfur Flow (g/kW-hr)

SO

2 (g/kW-hr)

Lloyds (Consistent A/FLloyds (Inconsistent AConsistent Data Regre

3-39
FIGURE 3-23

CO Emission Rate Data

0.11.0

10.0

100.0

1000.0

0% 20% 40% 60% 80% 100% 

Fractional Load

CO (g/kW-hr)

Lloyds (Consistent A/F)USCG (Consistent A/F)Lloyds (Inconsistent A/F)USCG (Inconsistent A/F)Consistent Data Regression 

3-40
FIGURE 3-24

CO2 Emission Rate Data

100

1000

10000

0% 20% 40% 60% 80% 100% 

Fractional Load

CO

2 (g/kW-hr)

Lloyds (Consistent A/F)USCG (Consistent A/F)Lloyds (Inconsistent A/F)USCG (Inconsistent A/F)Consistent Data Regression L

3-41
FIGURE 3-25

O2 Emission Rate Data

100

1000

10000

100000

1000000

0% 20% 40% 60% 80% 100% 

Fractional Load

O

2 (g/kW-hr)

Lloyds (Consistent A/F)USCG (Consistent A/F)Lloyds (Inconsistent A/F)USCG (Inconsistent A/F)Consistent Data Regression 

3-42
FIGURE 3-26

HC Emission Rate Data

0.0010.0100.1001.000

10.000

100.000

1000.000

0% 20% 40% 60% 80% 100% 

Fractional Load

HC (g/kW-hr)

Lloyds (Consistent A/F)USCG (Consistent A/F)Lloyds (Inconsistent A/F)USCG (Inconsistent A/F)Consistent Data Regression L

3-43
TABLE 3-5

MARINE ENGINE EMISSION FACTOR ALGORITHMS

Statistical Parameter PM NO NOx NO2 SO2 CO CO2 O2 HC 

Ex

Exponent (x) 1.5 1.5 1.5 1.5 n/a 1 1 1.5 1.5 Intercept (b) 0.2551 9.5181 10.4496 15.5247 -0.4792 0.1548 648.6 1298.1 0.3859 8Intercept t-stat 7.780 24.154 24.154 24.154 -1.124 0.323 33.957 4.101 1.429 6Significant intercept t? Yes Yes Yes Yes No No Yes Yes No Coefficient (a) 0.0059 0.1146 0.1255 0.1865 2.3735 0.8378 44.1 107.9 0.0667 Coefficient t-stat 23.143 19.391 19.391 19.391 28.924 17.700 23.374 22.769 17.064 23Significant coefficient t? Yes Yes Yes Yes Yes Yes Yes Yes Yes r

2 .95 .57 .57 .57 .78 .52 .65 .64 .52 

F-stat 536 376 376 376 837 313 546 512 291 Significant F-stat? Yes Yes Yes Yes Yes Yes Yes Yes Yes Observations 31 291 291 291 239 291 291 291 271 

1. All regressions but SO2 are in the form of: Emission Rate (g/kW-hr) = a (Fractional Load)-x + b

2. Fractional load is equal to actual engine output divided by rated engine output.3. The SO2 regression is in the form of: Emission Rate (g/kW-hr) = a (Fuel Sulfur Flow in g/kW-hr) + b

3-44
3-45

SO2, due to its obvious dependence on fuel sulfur content,

 is treated in a different fashion than

the remainder of the emission species. Theoretically, work-specific SO2 emissions should

approach two times work-specific fuel sulfur consumption (i.e., the ratio of the molecular weight

of SO2 to elemental sulfur is 64.0628/32.064, or 1.998), depending on the relative insignificance

of other sulfur sources (e.g., sulfur compounds in intake air) and sinks (e.g., sulfate emissions).

Since a direct linear relationship (with a zero intercept and a coefficient of about two) should be

evidenced, such a regression structure was evaluated for SO2 in lieu of the load-based regression

structures described above for other emission species.

The resulting regression statistics are presented in Table 3-5, where it is evident that the proper

zero intercept was derived, but that the derived fuel sulfur coefficient (2.37) is about 20 percent

too high. While this lends further support to an overestimation bias in the implied effective A/F

ratio of the underlying emission test data (i.e., A/F overestimation implies exhaust mass

overestimation, thereby implying emission species overestimation) and further investigation into

this phenomenon is recommended, it is not possible within the time or resource constraints of

this study to elaborate further. Certainly, a 20 percent error in emissions estimates in not

unreasonable given the overall variability of emission rates across engines. Nevertheless, the

apparent overestimation of SO2 implies a directional bias that should be addressed. In the

interim, EEA recommends using the theoretical coefficient for SO2 production (i.e., 1.998) in

place of that presented in Table 3-5.

It is also important to note that statistics presented for NO2 do not represent direct nitrogen

dioxide emissions, but rather the NO2 equivalent mass of emitted NOx. In effect, NO2 emission

rates reflect the net emission rate of NOx assuming all NOx is converted to NO2 (through

oxidation from a source not accounted for in the intake/exhaust stream, such as post-exhaust

atmospheric oxidation). This emission rate was produced as requested by the EPA, but should

be recognized as the maximum potential post-exhaust contribution to atmospheric NO2 and not

 



 Of course, carbon containing emission species are equally dependent on fuel carbon content. However, while total

fuel consumption is an acceptable surrogate for fuel carbon consumption due to the fact that carbon comprises the

bulk of the total fuel, the considerable variability of sulfur content across fuels makes SO2 emissions dependent

not on just fuel consumption per se (and thus co-dependent on load), but on fuel sulfur consumption in particular.
3-46

an indication of directly emitted NO2.

Statistics associated with each of the various regression structures evaluated by EEA are

presented in Appendix A. This includes both the full and partial load range regression structures

evaluated as well as separate regressions for: (1) all database records and (2) only those database

records satisfying the A/F ratio acceptance criteria discussed above. The improvement in

regression statistics for consistent A/F ratio records (designated in Appendix A as the “Yes Data”

regressions under the column labeled “A/F Criteria”) relative to those of the “All Data”

regressions across emission species is obvious and further illustrates the need to address any

remaining uncertainty in A/F ratios (and thus exhaust and emission species mass) to minimize

emission factor uncertainty.

The regression statistics presented in Table 3-5 apply to the aggregate emissions test database

and do not distinguish between the various engine types (e.g., two stroke versus four stoke) or

diesel fuels (e.g., distillate, light residual, etc.) encountered in marine vessel operations. Study

time and resource constraints as well as underlying test program structure prohibit an in-depth

evaluation of whether a finer resolution of marine vessel emission rates is appropriate. For

example, more two stroke engine data for which consistent A/F ratio estimates can be developed,

more larger engine emission data in general, more data using less common fuels, and data

collected from the same engine while operating on different fuels is critical to isolating and

quantifying distinctions between any or all of these elements. Given the current size and

construction of the underlying emissions test database, it is not possible to separate simple

engine-to-engine variability from potential engine or fuel type influences.

Nevertheless, to investigate the potential for such distinctions and provide an indication of the

need for further database enhancement, regression statistics for both two versus four stroke

engines and the various fuel types identified in the Lloyd’s database were generated. Regression

statistics for these various data sets are included in Appendix A. Figures A-1 through A-11 plot

all consistent A/F ratio test data by engine type and emission species, while Figures A-12
3-47

through A-21 plot the same data by test fuel type.

A review of Figures A-1 through A-21 and the regression statistics presented in Appendix A

reveals that it is certainly possible that both engine configuration and fuel type could be

significant influences on marine engine emission rates for one or more emission species.

Unfortunately, it is not possible given existing database structure and available time and resource

constraints to determine whether the apparent influences are attributable to simple variability

across engines or to specific engine or fuel characteristics. However, it is also apparent that the

scatter for most, if not all, of the separated engine type and fuel specific data is sufficiently wide

to support the general usage of the regression statistics presented in Table 3-5 until such time as

supplemental test data can be collected and supporting analysis performed. Nevertheless, EEA

certainly recommends that such evaluation be performed as soon as possible to validate the

general applicability of the presented regressions.

An initial investigation of the dependence of exhaust NOx on fuel nitrogen content was also

conducted. As shown in Figures 3-27 through 3-29, the scatter of estimated NOx emissions at

any given fuel nitrogen content is considerably wider than any trend in NOx with increasing fuel

nitrogen content. In fact, the only trend across fuel nitrogen content appears to be flat. Given

the overwhelming significance of intake air nitrogen on overall NOx formation, such a trend is

not surprising.

Lastly, all presented emission factors and emission factor analysis in this study apply solely to

marine internal combustion engines operating on diesel fuel (either distillate or residual).

Moreover, no distinction has been made between main propulsion engines and auxiliary engines.

This lack of distinction is based on two major factors, one technical and one logistical.

Technically, no significant differences are expected between the emission profiles of marine

engines used for propulsion versus auxiliary operations as the same engine makes and models are

 



 The USCG database does not identify the two versus four stroke configuration of several of its component test

engines and does not distinguish the various test fuels employed during testing, except to indicate that all fuels

were “diesel.” Therefore, all engine type statistics for “not indicated” engines and “diesel” fuel are based on

USCG data only. Conversely, all statistics for specific types of diesel fuel are based on Lloyd’s data only.
3-48

used to satisfy both applications. Logistically, the entire marine engine database used for this

study contains test data for only two auxiliary engines, prohibiting any detailed independent

assessment of auxiliary engines alone. Similarly, no emissions data for steam engines was

provided to EEA for review. For gas turbines, EPA provided a summary data sheet for only a

single oil tanker engine tested at two loads,11 while the USCG report4

 cites summary test results

for two additional gas turbines, but provides no supporting data such as that included for all

diesel engines tested. Therefore, the ability to develop detailed emission factors for gas turbines

is also quite limited.

Table 3-6 and Figure 3-30 summarize the available gas turbine emissions data and present

several arithmetic averages of reported mass emission rate data. Regressions were not performed

over the full load range of these turbines as no emissions rate data was provided at loads below

about 50 percent of rated output. While both NOx and CO may exhibit trends (NOx increasing

with load, CO decreasing with load), there simply is no data available to indicate whether these

trends hold true over the lower load ranges and, if so, what the general shape of the emissions

curve might be. Therefore, at this time, the use of simple arithmetic averages over the entire

range of test data or at each individual test data load point (50, 75, and 100 percent of rated

output) represents the only viable emission factor estimation technique. The resulting emission

factors for either approach are presented in Table 3-6. With appropriate qualifications given the

gas turbine database size, gas turbine emissions would, in general, appear to be about half those

of diesel marine engines for NOx and similar to diesel marine engine emissions for HC, CO, and

PM.
FIGURE 3-27

NO Emission Rate Data

1

10

100

1000

0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 

Fuel Nitrogen Content

NO (g/kW-hr)

Lloyds (gas oil)Lloyds (light fuel oil)Lloyds (intermediate Lloyds (heavy fuel oi

3-49
FIGURE 3-28

NOx Emission Rate Data

1

10

100

1000

0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 

Fuel Nitrogen Content

NO

x (g/kW-hr)

Lloyds (gas oil)Lloyds (light fuel oil)Lloyds (intermediate Lloyds (heavy fuel oi

3-50
FIGURE 3-29

NO2 Emission Rate Data

1

10

100

1000

0.00% 0.20% 0.40% 0.60% 0.80% 1.00% 

Fuel Nitrogen Content

NO

2 (g/kW-hr)

Lloyds (gas oil)Lloyds (light fuel oil)Lloyds (intermediate Lloyds (heavy fuel oi

3-51
TABLE 3-6

MARINE GAS TURBINE EMISSION RATE DATA

USCG "Sherman"

Parameter Chevron "Louisiana" Starboard Port Overall Average 50% Load Average 

Test Load (mW) 6.30 4.60 13.42 9.84 6.71 13.42 9.84 6.71

Rated Load (mW) 8.05 8.05 13.42 13.42 13.42 13.42 13.42 13.42

Fractional Load 0.78 0.57 1.00 0.73 0.50 1.00 0.73 0.50

Reported Emission Rate (pounds per hour)

PM 2.21 4.31

SO2 12.35 12.64 10.50 3.87 4.10 8.54 2.89 3.68

NOx 62.50 33.60 177.00 80.40 50.60 205.00 87.10 53.60

CO -1.17 0.31 2.98 27.40 39.50 31.60 26.90 43.50HC 2.67 16.00 3.41 0.50 7.23 1.47

Reported Emission Rate (g/kW-hr)

PM 0.16 0.42 0.29 0.42 

SO2 0.89 1.25 0.35 0.18 0.28 0.29 0.13 0.25 0.45 0.59 

NOx 4.50 3.31 5.98 3.71 3.42 6.93 4.01 3.62 4.44 3.45 

CO -0.08 0.03 0.10 1.26 2.67 1.07 1.24 2.94 1.15 1.88 HC 0.09 0.74 0.23 0.02 0.33 0.10 0.25 0.16 

3-52
FIGURE 3-30

Gas Turbine Emission Rates

-1

012345678

0% 20% 40% 60% 80% 100% 

Fractional Load

Emission Rate (g/kW-hr)

PM SO2 NOx CO HC

Solid markers are Chevron data,

open markers are USCG data.

Chevron does not report HC.

USCG does not report PM.

3-53

4-1

4. MARINE VESSEL CLASSIFICATIONS AND POWER RATINGS

4.1 CLASSIFICATIONS EMPLOYED IN LITERATURE

Three of the reports provided by EPA had utilized specific classifications of marine vessels that

varied both in detail and grouping, and these groupings are reviewed below.

The 1991 report by Booz-Allen9 categorizes oceangoing vessels into four types:

• container ships;

• tankers and bulk carriers;

• general cargo/vehicle carriers/RORO/and ocean-going tugs; and

• passenger liners and cruise ships.

Each particular category is then divided into weight classes in 25,000 ton deadweight ton (DWT)

steps (0 to 25, 25 to 50, etc) and an average horsepower is associated with each weight class for

every ship type. However, the horsepower data is identical across all ship types, except for

tankers and bulk carriers. The report also identifies horsepower for tankers and bulk carriers as

being higher than the horsepower (see Table 4-1) for other types within each weight class. The

Booz-Allen data is potentially incorrect, since tankers and bulk carriers cruise relatively slowly

(their cargo is not perishable or high cost), and typically have the lowest horsepower for a given

deadweight.

The Acurex report10 for SCAQMD also has a categorization scheme by deadweight and ship

type. The analysis relied on data from Lloyds, from the ships visiting San Pedro Bay. Acurex

classified ships by type and ‘design category’ where:

Design Category = (DWT)0.667 * (Service Speed)3

/104
4-2

TABLE 4-1

BOOZ-ALLEN CLASSIFICATION OF VESSELS

Type DWT (x1000) Range Horsepower

(1) Tankers & Bulk Carriers 0-25 16862

25-50 35742

50-75 59342

75-100 80582

100+ 104182

(2) All Others* 0-25 8560

25-50 11920

50-75 16120

75-100 19900

100+ 24100

* Booz-Allen has three categories for vessels: (a) container ships, (b) general cargo/vehicle carriers/RORO/

ocean-going tugs, and (c) passenger and cruise ships. However, all use the same HP to DWT relationship.
4-3

This equation is based on the well-known relationship between power to overcome drag, which

varies as the surface area in the water and the cube of speed. From the Lloyds registration data,

Acurex developed eight ship type categories namely:

• auto carriers;

• bulk carriers;

• container ships;

• general cargo ships;

• passenger ships;

• refrigerated cargo (reefer) ships;

• ‘roll-on, roll-off,’ or RORO; and

• tankers.

Each of the eight ship types is then further subdivided into design categories (up to eight) in step

of 200. These classifications are provided in Appendix C. However, it is not clear how many

ships were available in the sample for each combination of design category and ship type. An

examination of the data suggests significant sample variation since, in several instances,

horsepower declines with increasing design category range. The Acurex analysis showed that

the design category approach reduced the dispersion in horsepower within a ship type, but also

showed the dispersion reduction relative to using deadweight as an indicator was not large. In

addition, these are large variations in the percentage increase in horsepower for every 200 step in

design category range, indicating significant unexplained variation in horsepower.

The Arcadis (1999) report8

 for the EPA utilizes the same ship types as the Acurex study cited

above, but also provided cruise speeds by ship type. Bulk carriers, tankers and general cargo

ships had cruise speeds in the range of 15 to 16 knots, while reefers, RORO and container ships

had speeds of 20 to 22 knots. Auto carriers had an average speed of 18.3 knots while passenger

liner had an average speed of 19.9 knots. These estimates appear reasonable except for

passenger liners, where the relatively low average speed may have been influenced by the

sample selected; many passenger liners have speeds of 30 knots or higher. In addition, the

Arcadis report stated that there was considerable dispersion of speeds within ship type, but a
4-4

majority of ships were within ± 2 knots of the averages cited. This would suggest that bulk

carriers and tankers would have similar relationships between deadweight and horsepower, while

reefers, container ships and RORO may also have similar relationships.

Non-oceangoing vessels are typically more simply classified by type and horsepower. The

Booz-Allen report classifies these vessels into the following:

• fishing vessels;

• tugs;

• passenger ferries;

• dredging and construction ships;

• work/crew boats.

The Acurex report uses a virtually identical classification for non-oceangoing vessels as the

Booz-Allen classification, but further groups all vessels except for tugs and fishing vessels into a

single category called ‘other’ for emission estimation.

4.2 OPERATING MODE CLASSIFICATIONS IN LITERATURE

In general, ocean-going ships approach a port area at cruise speed, but reduce speed when they

are positioned within a few miles of the port (known as a precautionary area) to a speed of about

10 to 12 knots. Much closer to the docking area (about one mile), the ships slow to about five

knots and, assisted by tugboats, maneuver into the harbor and dock at the pier. Once at the pier,

only the auxiliary engines are used to provide electrical and accessory power, in a mode called

“hoteling.” The literature reviewed uniformly cites these four modes, through not all four modes

are used in all reports reviewed.

The Booz-Allen report cites these four modes, called full, half, slow and moored. The power

ratings, as a function of rated maximum power are 80, 40, 10, and zero for the four modes

respectively with regard to main engines. It was also assumed that for all ocean-going vessels,

the auxiliary power engines were operated at 500 kW. For harbor and fishing vessels, three

modes are utilized: full at 80 percent power, cruise at 50 percent power and slow at 20 percent
4-5

power. No hoteling emissions appear to be included from these classes of vessels.

The Acurex report assumed that at cruise, engines are operated at 80 percent of the maximum

continuous rating (MCR). Slow cruise was estimated as 12 knots, and the percent of power

required was calculated based on the cube of the ratio of 12 knots to actual cruise speed. Hence,

the percent of power used varies according to ship type, since for example, RORO and container

ship cruse much faster than bulk carriers and tankers. As a result, the percent of power used

varies from a little as 14 percent of MCR for container ships to 40 percent of MCR for bulk

carriers. For maneuvering, container ships were estimated to use only 10 percent of MCR, while

at the other extreme, bulk carriers were assumed to use 20 percent of MCR, based on

‘engineering judgement.”

The Acurex report also attempted to estimate auxiliary power loads under all modes including

hoteling. A survey based method was used, but no good relationships were found between

auxiliary loads and ship size or weight. Acurex recommend the following auxiliary power loads

independent of ship type (except for passenger ships) or weight:

• slow/fast cruise - 750 kW

• maneuvering - 1250 kW

• hoteling - 1000 kW

For passenger ships only, auxiliary power loads of 5000 kW were estimated under all conditions.

Acurex did not develop mode specific emission rates for harbor and fishing vessels, but simply

used annual fuel consumption average per horsepower to estimate emissions for tugs. Harbor

vessel activity was characterized at three modes representing 80, 50, and 20 percent of MCR.

Fishing vessel activity was characterized at 80 and 25 percent of MCR and at idle. (Fishing

vessels do not have large “hoteling” loads).
4-6

The newer Arcadis report8 does not vary significantly in its assessment of loads and operating

modes relative to the Acurex report. Table 4-2 shows the loads by vessel type and mode for

ocean going vessels, as provided in this report.

The Environment Canada report6 also cites four modes, but does not have specific values for

percent of power used by ship type on these modes.

4.3 ANALYSIS OF SHIP TYPE AND WEIGHT CATEGORIES

Under this work assignment, EPA provided a data base on ships operating at the West Coast that

contained information on ship type, weight, cruise speed and engine horsepower, obtained from

Lloyds. The database was similar in content to the one used by Arcadis in earlier analyses, and

has been provided to Arcadis for some current (ongoing) analyses.

While the date base contained about 5000 records, it included some data with incomplete records

for ship horsepower, type or weight. It also included data on non-oceangoing vessels such as

tugs, construction vessels and fishing vessels. Oceangoing vessels were classified in the scheme

cited in the Acurex report and included eight broad classifications by ship type as listed in

Section 4-1. The total sample of oceangoing ships with all necessary data was about 4100

vessels.

Ideally, rated horsepower would be more closely related to the maximum loaded weight of the

ship (i.e., empty weight + payload) but data on empty weight was not available for a large

fraction of the data records, and only deadweight (DWT) data is constantly available. EEA

attempted two sets of regressions that link horsepower to ship characteristics. The first is

between horsepower and DWT by ship type for each of the eight types. The second has

horsepower as the independent variable and uses (DWT)0.667 and (speed)3

 as the independent

variables. In addition, a regression across all ship types was performed using both regression

specifications.
4-7

TABLE 4-2

ENGINE LOADS BY SHIP TYPE FOR EACH OPERATING MODE

Ship Type Cruise Slow Cruise Maneuvering

Auto Carrier 80 20 15

Bulk Carrier 80 40 20

Container 80 10 10

General Cargo 80 35 20

Passenger 80 20 15

Reefer 80 20 15

RORO 80 15 10

Tanker 80 40 20

Source: Reference 8.
4-8

Table 4-3 shows the regressions for the eight types and across all ship types using (DWT) as the

independent variable. The regression has poor explanatory power when all ship types are

combined, but has reasonable explanatory power when each ship type is considered separately.

Most of the regressions by ship type have r2

 values in excess of 0.55.

Table 4-4 shows the regressions for the same ship types when (DWT)0.667 and (speed)3 are the

independent variables. These regressions have better explanatory power than the regressions

using DWT alone, but the improvements are not very large, except for the case when all ship

types are considered as one group. This is consistent with the observation that cruise speeds

within a ship type do not vary much, but vary significantly across ship types.

Our contacts with a few ports established that its is easier to obtain information on a ship’s

deadweight tonnage that to obtain cruise speed or horsepower (which would require purchase of

Lloyd’s data). Hence, the use of the (DWT) based regressions may be preferable to determine

horsepower. In examining the regression and the related scatter plots (not included in this

report), it was obvious that certain ship type categories could be combined

The regression coefficient for bulk carriers and tankers are very similar, and Arcadis also reports

a very similar top speed, so that combining these categories is appropriate. In addition, Table

4-4 also shows that the DWT coefficient for auto carriers, RORO, container ship and reefers are

quite similar (between 15 and 20) and could be combined. Plots of horsepower against (DWT)

for these ship types show that RORO reefers and auto carriers are distributed in the 5000 to

20,000 ton DWT range while most of the container ships are the 20,000 to 70,000 ton DWT

range. Because of their relatively high horsepower to weight ratio in comparison to general

cargo ships and tankers, and because of the fact that the sample size for these ship types was

(individually) only about 100 to 160, they were combined with container ships. Regression

coefficients for the combined categories are shown in Table 4-5.
4-9

TABLE 4-3

RESULTS OF REGRESSIONS BETWEEN HORSEPOWER

AND DEADWEIGHT TONNAGE

SHIP TYPE INTERCEPT DWT COEFF R-SQUARE

ALL

( N= 4103 )

9070

(42.05 )

0.1097

(26.01)

0.14

AUTO CARRIER

( N= 157 )

7602

(7.33)

0.4172

(5.75)

0.176

BULK CARRIER

(N= 1644)

6726

(54.54)

0.0985

(26.01)

0.55

CONTAINER

(N=489)

-749.4

(-0.61)

0.800

(26.29)

0.59

GENERAL CARGO

(N=641)

3046

(15.67)

0.288

(28.43)

0.56

PASSENGER

(N= 40)

-4877

(-1.24)

6.81

(9.97)

0.72

REEFER

(N=160)

1364

(2.23)

1.007

(14.93)

0.58

RORO

(N= 110)

4358

(6.70)

0.5364

(18.34)

0.76

TANKER

(N=861)

6579

(34.61)

0.1083

(41.16)

0.66

T-statistics in parentheses under coefficients.
4-10

TABLE 4-4

REGRESSIONS OF HORSE POWER vs DEADWEIGHT AND CRUISE SPEED

SHIP TYPE INTERCEPT DWT COEFF SPEED COEFF R-SQUARED

ALL

( N= 4103)

-4585

(23.18)

6.711

(51.95)

2.662

(92.66)

0.73

AUTOCARRIER

( N=157)

2956

(1.947)

14.41

(5.788)

0.381

(3.38)

0.25

BULK CARRIER

( N=1644)

1586

(6.514)

5.901

(48.55)

0.791

(13.11)

0.61

CONTAINER

( N=489)

-13924

(-10.36)

20.06

(12.60)

2.342

(16.63)

0.73

GENERAL

CARGO (N=839)

-1307

(-7.73)

8.819

(34.94)

1.202

(34.84)

0.80

PASSENGER

( N= 40)

-25305

(-4.43)

118.45

(5.228)

2,612

(3.498)

0.73

REEFER

( N= 160)

-2357

(-3.68)

17.00

(8.749)

0.861

(10.98)

0.77

RORO

( N= 110)

-3664

(-5.02)

16.18

(15.68)

1.386

(9.040)

0.88

TANKER

( N= 861)

156.6

(0.544)

6.271

(49.32)

1.291

(16.40)

0.78

T-statistics in parentheses. Equation uses (DWT)0.667 and (SPEED)3 as independent variables.
4-11

TABLE 4-5

RECCOMENDED SHIP TYPES AND REGRESSIONS

OF HORESEPOWER TO DEADWEIGHT

SHIP TYPE INTERCEPT DWT COEFF. R-SQUARE

BULK CARRIERS +TANKERS

(N=2505)

9070

(48.52)

0.101

(49.55)

0.67

PASSENGER

(N= 40)

-4877

(-1.24)

6.81

(9.97)

0.72

GENERAL CARGO

(N= 641)

3046

(15.67)

0.288

(28.43)

0.56

CONTAINER/RORO

AUTO CARRIER/REEFER

(N= 917)

2581

(5.50)

0.719

(47.27)

0.71

T-statistics in parentheses under coefficients.
4-12

Passenger ships posed a dilemma since there are only 40 ships in the database. The regression

show extremely high horsepower per DWT, and it implies that a 15,000 DWT ship would have

engines whose output is about 100,000 HP. In contrast, the Arcadis report estimates a similar

ship would have engines rated at 33,000 HP. It should be noted that the passenger ships in the

Arcadis report had relatively low top speeds of about 20 knots. If typical speeds are closer to 30

knots, the cubic relationship with speed would explain the differences in horsepower, since

(30/20)3 is 3.375, i.e., passenger ships capable of 30 knots cruise would require 3.375 times the

power of ships capable of 20 knot cruise. Nevertheless, the regressions should be treated with

caution because of the very small sample.

No independent data on the possible modes of operation and load factors was received. The

Arcadis report utilizing estimates of load factor derived from speeds appears more defensible

than using constant load factors across ship types for each mode. However, the load factor for

slow cruise (in the precautionary area) derived by Arcadis is based on an assumption that all

ships slow to 12 knots. It is entirely possible that larger ships such as bulk carriers and tankers

may operate slower as they cannot be maneuvered or stopped as easily as small ships, so that

using 12 knots for all ships may be incorrect. Due to the cubic relationship of power to speed,

slowing to ten knots would imply a load factor almost half that of slowing to 12 knots. The

cubic relationship also assumes that propeller and drivetrain efficiency remains constant over the

speed range which is likely incorrect. Due to the grouping of vessel types, and due to modest

changes to speed assumptions, EEA suggests load factors that are slightly different from the

Arcadis factors by mode, and these are listed in Table 4-6.

No alternatives to hoteling loads other than Arcadis survey based data are available. Hence, we

suggest these be utilized until more extensive survey based data becomes available.
4-13

TABLE 4-6

SUGGESTED LOADS BY MODE

(as percent of maximum continuous rating)

Cruise Slow Cruise Maneuvering

Bulk Carrier & Tankers 80 40 20

General Cargo 80 35 20

Passenger* 80 20 10

Container/RORO/Reefer/Auto Carrier 80 30 15

Auxiliary Loads in kW

Fast/Slow Cruise Maneuvering Hoteling

Passenger Ships 5000 5000 5000

All Others 750 1250 1000

* All values except main engine load categories marked are from Reference 8.
4-14

Data on the horsepower and operating modes of all non-oceangoing hips is much more sparse.

Based on the data provided by EPA, EEA calculated the following average rated horsepower by

vessel type:

• Fishing Vessels - 1106

• Tug - 4268

• Ferries - 2415

• Yachts - 1863

• Harbor Operations - 5046

No data is available to compare these estimates, but these estimates are based on samples of

about 100 vessels in each class.

Operating mode data on non-oceangoing vessels is not easy to characterize. Typical estimates

have been based on power factors of 80 percent, 40 percent, 20 percent and idle, for cruise, slow

cruise, maneuvering, and trawling or waiting. No estimates of auxiliary loads for such vessels

are available.

The operating mode data on both oceangoing and non-oceangoing vessels appears to be derived

from numerous assumptions that have not been subjected to any validation by EEA. However,

this is the best available data within the time and resource constraints of this project.
5-1

5. EMISSION FACTOR SUMMARY

The analysis presented in this report derives new emission factors for marine vessels, based on

data from the Lloyds Marine Exhaust Emissions Research Program, and the Coast Guard Test

Program. Unlike marine emission factors that were historically specified in units of fuel

consumption, the emission factors are specified in units of work (kW-hr) and are dependent on

engine load factor, which is the ratio of actual output to rated output based on the maximum

continuous rating.

The computation of emissions (and fuel consumption, if required) can be performed by ship type

for a given port and requires the following inputs:

• The number of calls to the port by vessel class and deadweight tonnage.

• The time spent, by ship type, in each of four operating modes defined as: normal cruise,

slow cruise, maneuvering and hoteling.

Alternatively, if ship horsepower is directly available for each ship, classification by deadweight

tonnage is not required. In addition, the user may define alternative modes of operation and

typical engine load factors by mode.

The basic equations used for the calculation are:

TIMEVCC, DWT, MODE = CALLSVCC, DWT × LENGTHVCC,DWT × %TIMEVCC, DWT, MODE/100

EMISSIONSVCC,DWT,MODE = (EF)(LFMODE) × (HP)(DWT) × LFMODE × TIMEVCC, DWT, MODE

where:

VCC is the vessel class (tanker, RORO, etc.)

DWT is the deadweight tons

EF is the emissions factor

LF is the mode specific load factor
5-2

For the calculation, the TIME equation requires port specific inputs, while this report provides

the EF and HP relationships.

The emission factors and fuel consumption rates are derived from substantially more data than

earlier emission factors, and represent an improvement over the current fuel based emission

factors. However, the emission factors derived are subject to the following cautions:

• A significant portion of the database had measurements that yielded inconsistent values

of air-fuel ratio depending on the calculation methodology employed. These records

were excluded from the analysis, but the remaining database was still adequate for

analysis.

• Some of the data reported suspiciously low values of HC concentrations (below one ppb),

but these data were retained in the analysis. However, the number of records with low

HC values is small.

• There are concerns regarding the determination of output power at each test mode, for

about ten percent of the records.

• Most of the data analyzed is on engines rated at less than 8000 kW. Most of the data

points eliminated from analysis due to errors are from higher output engines, which are

mostly two-stroke engines. Hence, the applicability of the derived emission factors to all

engine sizes is not firmly established.

The emissions factor algorithms derived are of the form:

E (g/kW-hr) = a (Fractional Load)-x + b

where E is the emissions rate per unit of work. The data analysis showed no statistically

significant differences in emissions rates by engine size or output range, or by

two-stroke/four-stoke, subject to the caveats detailed above. Emissions rates for SO2 are based

on (fuel consumption x sulfur content of fuel) since all SO2 emissions are fuel derived. Table 5-1

provides a summary of HC, CO, NOx, NO2, PM, CO2, and SO2 emission factors and fuel

consumption as a function of load. The fuel consumption factor algorithm (derived from the

same database as the emission factors) is also in the same equation form as emission factor

algorithms. These emissions factor and fuel consumption rate algorithms are applicable to all

engine sizes since the emissions data showed no statistically significant difference across engine

sizes. In all cases (including fuel consumption), the algorithms provide the rates per unit of work,

i.e. per kW-hr. In order to obtain the absolute emission or fuel consumption level in grams, it is
5-3

TABLE 5-1

MARINE ENGINE EMISSION FACTOR

AND FUEL CONSUMPTION ALGORITHMS

(in g/kW-hr, for all marine engines)

Pollutant Exponent (x) Intercept (b) Coefficient (a)

PM 1.5 0.2551 0.0059

NOx 1.5 10.4496 0.1255

NO2 1.5 15.5247 0.18865

SO2 n/a n/s 2.3735

CO 1 n/s 0.8378

HC 1.5 n/s 0.0667

CO2 1 648.6 44.1

1. All regressions but SO2 are in the form of:

Emissions Rate (g/kW-hr) = a (Fractional Load)-x + b

2. Fractional load is equal to actual engine output divided by rated engine output.

3. The SO2 regression is the form of:

Emissions Rate (g/kW-hr) = a (Fuel Sulfur Flow in g/kW-hr) + b

4. Fuel Consumption (g/kW-hr) = 14.12/(Fractional Load) + 205.717

5. n/a is not applicable, n/s is not statistically significant.
5-4

necessary to multiply the rates per unit of work by the work in kilowatts and the time in hours, as

indicated by the equation listed on page 5-1 for emissions.

While the rederivation of emission factors and fuel consumption rate are central to this report,

the relationship of engine rated horsepower to ship type and deadweight tonnage was also

investigated. Oceangoing ships were classified into four types and their horsepower was related

to deadweight (DWT) using linear regressions. The results are:

(1) Bulk Carriers and Tankers: HP = 9070 + 0.101 (DWT)

(2) General Cargo Ships: HP = 3046 + 0.288 (DWT)

(3) Container/RORO/Auto Carriers/Refrigerated Ships: HP = 2581 + 0.719 (DWT)

(4) Passenger Ships: HP = -4877 + 6.81 (DWT)

The relationship for the passenger ship category is the most uncertain since the sample of ships

in this category was very small (40).

For all non-ocean going vessels, the empty weight or deadweight is generally not available in the

Lloyd’s registration data, so that for these classes of vessels, only an average horsepower across

the class was computed. The values are based on a sample of about 100 vessels in each category

and the results are:

• fishing vessels - 1106 HP;

• tugs - 4268 HP;

• ferries - 2415 HP;

• yachts - 1863 HP;

• harbor operations - 5046 HP;

The values could be used as default values in the absence of actual HP data on the vessels

operating at a specific port.
5-5

Operating modes were divided into four types:

• normal cruise;

• slow cruise;

• maneuvering;

• docking (hoteling).

No independent data analysis was performed on the load factors for the engines (main and

auxiliary) at these operating modes. Results from literature are summarized, and the best source

of load factor data is from a recent report by Arcadis. Nevertheless, this data relies on a number

of assumptions that may not be true, especially for a specific port. The auxiliary engine loads (in

absolute kilowatts) may be the most arbitrary as they are specified independent of ship size or

weight.

Computation of emissions from auxiliary engines require the use of the same emission factors

specified in Table 5-1, and are evaluated at a load factor equal to one (i.e., at full load). Hence,

the equation for emission from auxiliary engines is given by

Emissions = (EF)(LF=1) × Auxiliary Power (kW) × TimeVCC,DWT,HOTEL

Table 5-2 shows the suggested load factors for both ocean-going vessels and non-ocean-going

vessels. While these values could be reasonable default values, the use of port specific load

factors is preferable, if available.
5-6

TABLE 5-2

SUGGESTED LOAD FACTORS

(as percent of maximum continuous rating)

Vessel Type Cruise Slow Cruise Maneuvering

Bulk Carriers & Tankers 80 40 20

General Cargo 80 35 20

Passenger 80 20 10

Container/RORO/Reefer/Auto Carrier 80 30 15

All non-oceangoing 80 40 20

SUGGESTED AUXILIARY LOADS IN KW

(ocean-going vessels only)*

Slow Cruise Maneuvering Hoteling

Passenger Ships 5000 5000 5000

All others 750 1250 1000

* Non-oceangoing vessels do not have separate auxiliary loads of significance.
6-1

6. REFERENCES

1. Marine Exhaust Emissions Research Programme: Steady State Operation, Lloyd’s Register

of Shipping, London, United Kingdom, 1990.

2. Marine Exhaust Emissions Research Programme: Steady State Operation, Slow Speed

Addendum, Lloyd’s Register of Shipping, London, United Kingdom, 1991.

3. Marine Exhaust Emissions Research Programme, Lloyd’s Register of Shipping, London,

United Kingdom, 1995.

4. Shipboard Marine Engines Emission Testing for the United States Coast Guard, Delivery

Order Number 31, Final Report, prepared by Environmental Transportation Consultants for

the Volpe National Transportation Systems Center and the United States Coast Guard

Headquarters Naval Engineering Division, undated (emissions testing conducted in 1995).

5. BC Ferries Emissions Test Program, Report for the BC Ferry Corporation, ERMD

#98-26711, Environment Canada, Ottawa, Ontario, Canada, 1998

6. Port of Vancouver Marine Vessel Emissions Test Project, Final Report, ERMD #97-04,

Environment Canada, Ottawa, Ontario, Canada, 1997

7. Marine Emissions Quantification – BCFC Ferries operating in Greater Vancouver Regional

District Airshed, 97/EE/7002, Final Report, prepared by Lloyd’s Register of Shipping for the

British Columbia Ferry Corporation, London, United Kingdom, 1997.

8. Analysis of Marine Emissions in the South Coast Air Basin, Draft Report, EPA Contract

Number 68-C6-0068, Work Assignment Number 0-02, prepared by Acurex Environmental

Corporation for the U.S. Environmental Protection Agency, 1999.

9. Inventory of Air Pollutant Emissions from Marine Vessels, Final Report, prepared by

Booz-Allen & Hamilton for the California Air Resources Board, Revised March 1991

10. Marine Vessel Emission Inventory and Control Strategies, Final Report, prepared by Acurex

Environmental Corp., for the South Coast Air Quality Management District, 1996

11. Facsimile transmittal on gas turbine emission rates from the Chevron “Louisiana,” Brian

Shafritz of the Santa Barbara County (California) Air Pollution Control District to Gregg

Jansen [sic] of the U.S. Environmental Protection Agency, June 1, 1999.

APPENDIX A

EMISSION FACTOR REGRESSION SUMMARIES
A-2

KEY TO APPENDIX TERMS:

1. All regressions are of the form:

Emission rate (g/kW-hr) = (Coefficient × Independent Variable) + Intercept

where: Coefficient = Value in column labeled “Coeff,”

Intercept = Value in column labeled “Intercept,” and

Independent Variable = Parameter indicated in column labeled “Param” as follows:

“FL” = Fractional Load,

“1/(FL^e)” = Fractional Load to the negative “e” power, and

“Fuel S” = Fuel sulfur flow in g/kW-hr.

2. Where applicable, the exponent “e” is indicated in the upper center of each regression

summary.

3. Entries in the column labeled “A/F Criteria” have the following meanings:

“All Data” indicates that no data was excluded from the regression

analysis due to inconsistencies in estimated A/F ratio.

“Yes Data” indicates that only data meeting the consistent A/F ratio

criteria described in Section 3 is included in the regression analysis.

4. Entries in the column labeled “Loads Covered” have the following meanings:

“FL ge 0” means all data with an indicated fractional load greater than

or equal to zero.

“FL ge 20” means all data with an indicated fractional load greater than

or equal to 20 percent.

“FL lt 20” means all data with an indicated fractional load of less than

20 percent.
A-3

KEY TO APPENDIX TERMS

(Continued)

5. Entries in the column labeled “Cycles Covered” have the following meanings:

“All” means all reported engine types are included in the regression

analysis.

“2 Stroke” means only data for reported two stroke engines are included

in the regression analysis.

“4 Stroke” means only data for reported four stroke engines are

included in the regression analysis.

“Not Ind.” (not indicated) means only data for USCG engines not

reported as either two or four stroke are included in the regression

analysis.

6. Entries in the column labeled “Fuels Covered” have the following meanings:

“All” means all reported fuel types are included in the regression

analysis.

“Diesel” means only USCG fuel types (all identified simply as “diesel”)

are included in the regression analysis.

“Gas Oil” means only data for reported gas oil fuel are included in the

regression analysis.

“Gas Oil” means only data for reported gas oil fuel are included in the

regression analysis.

“Hvy FO” means only data for reported heavy fuel oil fuel are included

in the regression analysis.

“Int FO” means only data for reported intermediate fuel oil fuel are

included in the regression analysis.

“Light FO” means only data for reported light fuel oil fuel are included

in the regression analysis.
A-4

KEY TO APPENDIX TERMS

(Continued)

7. Entries in the columns labeled “Int-T” and Coeff-T” indicate the regression t statistics for

the intercept and coefficient respectively.

8. Entries in the column labeled “r2” indicate the regression correlation coefficient.

9. Entries in the column labeled “F” indicate the regression model variance F statistic.

10. Entries in the three columns labeled “Sig?” indicate, from left to right, whether (“Yes”) or

not (“No”) the indicated intercept t statistic, coefficient t statistic, and variance F statistic are

significant at the 99 percent confidence level.

11. Entries in the column labeled “Obs” indicate the number of observations used in the

regression analysis.
REGRESSION SUMMARY FOR: PM Exponent = 1.5

A/F Loads Cycles Fuels Predic

Criteria Covered Covered Covered Intercept Int-T Sig? Coeff Coeff-T Sig? Param r2 F Sig? Obs 0.05 0.1

All Data FL ge 0 All All 2.4352 2.981 Yes -3.6383 -1.892 No FL 0.10 3.58 No 35 2.435 2.4All Data FL ge 0 All All 0.8332 1.430 No 0.0066 1.593 No 1/(FL^e) 0.07 2.54 No 35All Data FL ge 20 All All 0.3344 2.696 No -0.0482 -0.221 No FL 0.00 0.05 No 19All Data FL lt 20 All All 4.5556 2.245 No -25.4900 -1.300 No FL 0.11 1.69 No 16All Data FL lt 20 All All 1.8897 1.272 No 0.0035 0.486 No 1/(FL^e) 0.02 0.24 No 16

Yes Data FL ge 0 All All 0.9289 4.369 Yes -1.1052 -2.346 No FL 0.16 5.50 No 31 0.929 0.9Yes Data FL ge 0 All All 0.2551 7.780 Yes 0.0059 23.143 Yes 1/(FL^e) 0.95 535.58 Yes 31 0.784 0.4Yes Data FL ge 20 All All 0.3344 2.696 No -0.0482 -0.221 No FL 0.00 0.05 No 19Yes Data FL lt 20 All All 2.4562 6.000 Yes -15.5027 -4.426 No FL 0.66 19.59 Yes 12 2.456 2.4Yes Data FL lt 20 All All 0.1797 3.921 Yes 0.0061 27.472 Yes 1/(FL^e) 0.99 754.73 Yes 12 0.726 0.3Yes Data FL ge 0 Not Ind. All 0.9533 3.927 Yes -1.1154 -1.967 No FL 0.14 3.87 No 25 0.953 0.9Yes Data FL ge 0 2 Stroke All 0.0000 0.000 0.0000 0.000 FL 0.00 0.00 0Yes Data FL ge 0 4 Stroke All 0.4088 4.140 Yes -0.2656 -1.443 No FL 0.34 2.08 No 6 0.409 0.4Yes Data FL ge 0 Not Ind. All 0.2558 6.235 Yes 0.0059 20.590 Yes 1/(FL^e) 0.95 423.95 Yes 25 0.785 0.4Yes Data FL ge 0 2 Stroke All 0.0000 0.000 0.0000 0.000 1/(FL^e) 0.00 0.00 0Yes Data FL ge 0 4 Stroke All 0.1828 2.955 No 0.0274 1.602 No 1/(FL^e) 0.39 2.57 No 6Yes Data FL ge 0 All Diesel 0.9289 4.369 Yes -1.1052 -2.346 No FL 0.16 5.50 No 31 0.929 0.9Yes Data FL ge 0 All Gas Oil 0.0000 0.000 0.0000 0.000 FL 0.00 0.00 0Yes Data FL ge 0 All Hvy FO 0.0000 0.000 0.0000 0.000 FL 0.00 0.00 0Yes Data FL ge 0 All Int FO 0.0000 0.000 0.0000 0.000 FL 0.00 0.00 0Yes Data FL ge 0 All Light FO 0.0000 0.000 0.0000 0.000 FL 0.00 0.00 0Yes Data FL ge 0 All Diesel 0.2551 7.780 Yes 0.0059 23.143 Yes 1/(FL^e) 0.95 535.58 Yes 31 0.784 0.4Yes Data FL ge 0 All Gas Oil 0.0000 0.000 0.0000 0.000 1/(FL^e) 0.00 0.00 0Yes Data FL ge 0 All Hvy FO 0.0000 0.000 0.0000 0.000 1/(FL^e) 0.00 0.00 0Yes Data FL ge 0 All Int FO 0.0000 0.000 0.0000 0.000 1/(FL^e) 0.00 0.00 0Yes Data FL ge 0 All Light FO 0.0000 0.000 0.0000 0.000 1/(FL^e) 0.00 0.00 0Yes Data FL ge 0 Not Ind. Diesel 0.9533 3.927 Yes -1.1154 -1.967 No FL 0.14 3.87 No 25 0.953 0.9Yes Data FL ge 0 2 Stroke Diesel 0.0000 0.000 0.0000 0.000 FL 0.00 0.00 0Yes Data FL ge 0 2 Stroke Gas Oil 0.0000 0.000 0.0000 0.000 FL 0.00 0.00 0Yes Data FL ge 0 2 Stroke Hvy FO 0.0000 0.000 0.0000 0.000 FL 0.00 0.00 0Yes Data FL ge 0 2 Stroke Int FO 0.0000 0.000 0.0000 0.000 FL 0.00 0.00 0Yes Data FL ge 0 4 Stroke Diesel 0.4088 4.140 Yes -0.2656 -1.443 No FL 0.34 2.08 No 6 0.409 0.4Yes Data FL ge 0 4 Stroke Gas Oil 0.0000 0.000 0.0000 0.000 FL 0.00 0.00 0Yes Data FL ge 0 4 Stroke Light FO 0.0000 0.000 0.0000 0.000 FL 0.00 0.00 0Yes Data FL ge 0 Not Ind. Diesel 0.2558 6.235 Yes 0.0059 20.590 Yes 1/(FL^e) 0.95 423.95 Yes 25 0.785 0.4Yes Data FL ge 0 2 Stroke Diesel 0.0000 0.000 0.0000 0.000 1/(FL^e) 0.00 0.00 0Yes Data FL ge 0 2 Stroke Gas Oil 0.0000 0.000 0.0000 0.000 1/(FL^e) 0.00 0.00 0Yes Data FL ge 0 2 Stroke Hvy FO 0.0000 0.000 0.0000 0.000 1/(FL^e) 0.00 0.00 0Yes Data FL ge 0 2 Stroke Int FO 0.0000 0.000 0.0000 0.000 1/(FL^e) 0.00 0.00 0Yes Data FL ge 0 4 Stroke Diesel 0.1828 2.955 No 0.0274 1.602 No 1/(FL^e) 0.39 2.57 No 6Yes Data FL ge 0 4 Stroke Gas Oil 0.0000 0.000 0.0000 0.000 1/(FL^e) 0.00 0.00 0Yes Data FL ge 0 4 Stroke Light FO 0.0000 0.000 0.0000 0.000 1/(FL^e) 0.00 0.00 0

A-5
REGRESSION SUMMARY FOR: NO Exponent = 1.5

A/F Loads Cycles Fuels Predic

Criteria Covered Covered Covered Intercept Int-T Sig? Coeff Coeff-T Sig? Param r2 F Sig? Obs 0.05 0.1

All Data FL ge 0 All All 20.0268 19.658 Yes -14.9792 -7.862 No FL 0.15 61.81 Yes 356 20.027 20.0All Data FL ge 0 All All 10.4583 18.481 Yes 0.1110 14.647 Yes 1/(FL^e) 0.38 214.54 Yes 356 20.386 13.9All Data FL ge 20 All All 10.7756 22.772 Yes -1.7939 -2.449 No FL 0.02 6.00 No 241 10.776 10.7All Data FL lt 20 All All 36.0476 11.209 Yes -158.9668 -5.124 No FL 0.19 26.25 Yes 115 36.048 36.0All Data FL lt 20 All All 14.1805 7.215 Yes 0.0939 6.270 Yes 1/(FL^e) 0.26 39.31 Yes 115 22.577 17.1

Yes Data FL ge 0 All All 16.9497 17.580 Yes -10.8279 -6.407 No FL 0.12 41.06 Yes 291 16.950 16.9Yes Data FL ge 0 All All 9.5181 24.154 Yes 0.1143 19.391 Yes 1/(FL^e) 0.57 376.02 Yes 291 19.746 13.1Yes Data FL ge 20 All All 10.3842 21.257 Yes -1.6405 -2.207 No FL 0.02 4.87 No 217 10.384 10.3Yes Data FL lt 20 All All 33.9582 8.753 Yes -144.4380 -4.358 No FL 0.21 18.99 Yes 74 33.958 33.9Yes Data FL lt 20 All All 11.4486 7.186 Yes 0.1070 8.884 Yes 1/(FL^e) 0.52 78.93 Yes 74 21.015 14.8Yes Data FL ge 0 Not Ind. All 18.6862 11.938 Yes -14.8995 -4.426 No FL 0.45 19.59 Yes 26 18.686 18.6Yes Data FL ge 0 2 Stroke All 9.5052 6.425 Yes 3.3223 1.239 No FL 0.03 1.54 No 45 9.505 9.5Yes Data FL ge 0 4 Stroke All 17.7374 14.654 Yes -12.2715 -5.936 No FL 0.14 35.23 Yes 220 17.737 17.7Yes Data FL ge 0 Not Ind. All 10.8992 17.308 Yes 0.0461 10.252 Yes 1/(FL^e) 0.81 105.10 Yes 26 15.022 12.3Yes Data FL ge 0 2 Stroke All 11.5228 15.199 Yes -0.0331 -1.394 No 1/(FL^e) 0.04 1.94 No 45 11.523 11.5Yes Data FL ge 0 4 Stroke All 8.7618 24.437 Yes 0.1701 27.588 Yes 1/(FL^e) 0.78 761.12 Yes 220 23.980 14.1Yes Data FL ge 0 All Diesel 13.8772 11.302 Yes -7.2368 -3.571 No FL 0.21 12.76 Yes 49 13.877 13.8Yes Data FL ge 0 All Gas Oil 20.6879 9.899 Yes -18.7851 -4.675 No FL 0.16 21.86 Yes 114 20.688 20.6Yes Data FL ge 0 All Hvy FO 10.7749 4.684 Yes 2.3879 0.616 No FL 0.02 0.38 No 22 10.775 10.7Yes Data FL ge 0 All Int FO 14.3115 3.934 Yes 0.8539 0.128 No FL 0.00 0.02 No 10 14.311 14.3Yes Data FL ge 0 All Light FO 14.9135 14.592 Yes -7.4032 -4.384 No FL 0.17 19.22 Yes 96 14.913 14.9Yes Data FL ge 0 All Diesel 8.9596 13.947 Yes 0.0466 7.634 Yes 1/(FL^e) 0.55 58.29 Yes 49 13.129 10.4Yes Data FL ge 0 All Gas Oil 8.5884 13.755 Yes 0.1679 20.753 Yes 1/(FL^e) 0.79 430.69 Yes 114 23.604 13.8Yes Data FL ge 0 All Hvy FO 12.5316 11.263 Yes -0.0974 -0.611 No 1/(FL^e) 0.02 0.37 No 22 12.532 12.5Yes Data FL ge 0 All Int FO 16.4739 8.921 Yes -0.2364 -1.546 No 1/(FL^e) 0.23 2.39 No 10 16.474 16.4Yes Data FL ge 0 All Light FO 8.8753 23.720 Yes 0.1754 13.124 Yes 1/(FL^e) 0.65 172.25 Yes 96 24.562 14.4Yes Data FL ge 0 Not Ind. Diesel 18.6862 11.938 Yes -14.8995 -4.426 No FL 0.45 19.59 Yes 26 18.686 18.6Yes Data FL ge 0 2 Stroke Diesel 5.7116 39.867 Yes 0.8915 3.117 No FL 0.58 9.72 No 9 5.712 5.7Yes Data FL ge 0 2 Stroke Gas Oil 9.3553 3.353 No -3.7954 -0.572 No FL 0.14 0.33 No 4Yes Data FL ge 0 2 Stroke Hvy FO 10.7749 4.684 Yes 2.3879 0.616 No FL 0.02 0.38 No 22 10.775 10.7Yes Data FL ge 0 2 Stroke Int FO 14.3115 3.934 Yes 0.8539 0.128 No FL 0.00 0.02 No 10 14.311 14.3Yes Data FL ge 0 4 Stroke Diesel 10.3081 4.813 Yes -2.9725 -1.180 No FL 0.10 1.39 No 14 10.308 10.3Yes Data FL ge 0 4 Stroke Gas Oil 21.2210 9.822 Yes -19.4814 -4.720 No FL 0.17 22.28 Yes 110 21.221 21.2Yes Data FL ge 0 4 Stroke Light FO 14.9135 14.592 Yes -7.4032 -4.384 No FL 0.17 19.22 Yes 96 14.913 14.9Yes Data FL ge 0 Not Ind. Diesel 10.8992 17.308 Yes 0.0461 10.252 Yes 1/(FL^e) 0.81 105.10 Yes 26 15.022 12.3Yes Data FL ge 0 2 Stroke Diesel 6.2249 74.161 Yes -0.0058 -4.130 No 1/(FL^e) 0.71 17.06 Yes 9 6.225 6.2Yes Data FL ge 0 2 Stroke Gas Oil 6.3121 6.932 No 0.0575 3.339 No 1/(FL^e) 0.85 11.15 No 4Yes Data FL ge 0 2 Stroke Hvy FO 12.5316 11.263 Yes -0.0974 -0.611 No 1/(FL^e) 0.02 0.37 No 22 12.532 12.5Yes Data FL ge 0 2 Stroke Int FO 16.4739 8.921 Yes -0.2364 -1.546 No 1/(FL^e) 0.23 2.39 No 10 16.474 16.4Yes Data FL ge 0 4 Stroke Diesel 8.4415 3.834 Yes -0.0495 -0.096 No 1/(FL^e) 0.00 0.01 No 14 8.441 8.4Yes Data FL ge 0 4 Stroke Gas Oil 8.7582 13.922 Yes 0.1695 20.995 Yes 1/(FL^e) 0.80 440.78 Yes 110 23.917 14.1Yes Data FL ge 0 4 Stroke Light FO 8.8753 23.720 Yes 0.1754 13.124 Yes 1/(FL^e) 0.65 172.25 Yes 96 24.562 14.4

A-6
REGRESSION SUMMARY FOR: NOx Exponent = 1.5

A/F Loads Cycles Fuels Predic

Criteria Covered Covered Covered Intercept Int-T Sig? Coeff Coeff-T Sig? Param r2 F Sig? Obs 0.05 0.1

All Data FL ge 0 All All 21.9867 19.658 Yes -16.4451 -7.862 No FL 0.15 61.81 Yes 356 21.987 21.9All Data FL ge 0 All All 11.4817 18.481 Yes 0.1219 14.647 Yes 1/(FL^e) 0.38 214.54 Yes 356 22.381 15.3All Data FL ge 20 All All 11.8301 22.772 Yes -1.9694 -2.449 No FL 0.02 6.00 No 241 11.830 11.8All Data FL lt 20 All All 39.5753 11.209 Yes -174.5233 -5.124 No FL 0.19 26.25 Yes 115 39.575 39.5All Data FL lt 20 All All 15.5683 7.215 Yes 0.1031 6.270 Yes 1/(FL^e) 0.26 39.31 Yes 115 24.787 18.8

Yes Data FL ge 0 All All 18.6084 17.580 Yes -11.8876 -6.407 No FL 0.12 41.06 Yes 291 18.608 18.6Yes Data FL ge 0 All All 10.4496 24.154 Yes 0.1255 19.391 Yes 1/(FL^e) 0.57 376.02 Yes 291 21.678 14.4Yes Data FL ge 20 All All 11.4004 21.257 Yes -1.8011 -2.207 No FL 0.02 4.87 No 217 11.400 11.4Yes Data FL lt 20 All All 37.2814 8.753 Yes -158.5718 -4.358 No FL 0.21 18.99 Yes 74 37.281 37.2Yes Data FL lt 20 All All 12.5690 7.186 Yes 0.1174 8.884 Yes 1/(FL^e) 0.52 78.93 Yes 74 23.071 16.2Yes Data FL ge 0 Not Ind. All 20.5149 11.938 Yes -16.3577 -4.426 No FL 0.45 19.59 Yes 26 20.515 20.5Yes Data FL ge 0 2 Stroke All 10.4352 6.425 Yes 3.6475 1.239 No FL 0.03 1.54 No 45 10.435 10.4Yes Data FL ge 0 4 Stroke All 19.4732 14.654 Yes -13.4724 -5.936 No FL 0.14 35.23 Yes 220 19.473 19.4Yes Data FL ge 0 Not Ind. All 11.9658 17.308 Yes 0.0506 10.252 Yes 1/(FL^e) 0.81 105.10 Yes 26 16.492 13.5Yes Data FL ge 0 2 Stroke All 12.6504 15.198 Yes -0.0363 -1.394 No 1/(FL^e) 0.04 1.94 No 45 12.650 12.6Yes Data FL ge 0 4 Stroke All 9.6193 24.437 Yes 0.1868 27.588 Yes 1/(FL^e) 0.78 761.12 Yes 220 26.327 15.5Yes Data FL ge 0 All Diesel 15.2353 11.302 Yes -7.9452 -3.572 No FL 0.21 12.76 Yes 49 15.235 15.2Yes Data FL ge 0 All Gas Oil 22.7124 9.899 Yes -20.6235 -4.675 No FL 0.16 21.86 Yes 114 22.712 22.7Yes Data FL ge 0 All Hvy FO 11.8293 4.684 Yes 2.6216 0.616 No FL 0.02 0.38 No 22 11.829 11.8Yes Data FL ge 0 All Int FO 15.7119 3.934 Yes 0.9377 0.128 No FL 0.00 0.02 No 10 15.712 15.7Yes Data FL ge 0 All Light FO 16.3730 14.592 Yes -8.1277 -4.384 No FL 0.17 19.22 Yes 96 16.373 16.3Yes Data FL ge 0 All Diesel 9.8363 13.947 Yes 0.0512 7.634 Yes 1/(FL^e) 0.55 58.28 Yes 49 14.413 11.4Yes Data FL ge 0 All Gas Oil 9.4289 13.755 Yes 0.1843 20.753 Yes 1/(FL^e) 0.79 430.69 Yes 114 25.913 15.2Yes Data FL ge 0 All Hvy FO 13.7580 11.263 Yes -0.1069 -0.611 No 1/(FL^e) 0.02 0.37 No 22 13.758 13.7Yes Data FL ge 0 All Int FO 18.0862 8.921 Yes -0.2595 -1.546 No 1/(FL^e) 0.23 2.39 No 10 18.086 18.0Yes Data FL ge 0 All Light FO 9.7439 23.720 Yes 0.1925 13.124 Yes 1/(FL^e) 0.65 172.24 Yes 96 26.966 15.8Yes Data FL ge 0 Not Ind. Diesel 20.5149 11.938 Yes -16.3577 -4.426 No FL 0.45 19.59 Yes 26 20.515 20.5Yes Data FL ge 0 2 Stroke Diesel 6.2705 39.887 Yes 0.9784 3.118 No FL 0.58 9.72 No 9 6.270 6.2Yes Data FL ge 0 2 Stroke Gas Oil 10.2705 3.354 No -4.1654 -0.572 No FL 0.14 0.33 No 4Yes Data FL ge 0 2 Stroke Hvy FO 11.8293 4.684 Yes 2.6216 0.616 No FL 0.02 0.38 No 22 11.829 11.8Yes Data FL ge 0 2 Stroke Int FO 15.7119 3.934 Yes 0.9377 0.128 No FL 0.00 0.02 No 10 15.712 15.7Yes Data FL ge 0 4 Stroke Diesel 11.3168 4.813 Yes -3.2635 -1.180 No FL 0.10 1.39 No 14 11.317 11.3Yes Data FL ge 0 4 Stroke Gas Oil 23.2977 9.822 Yes -21.3880 -4.720 No FL 0.17 22.28 Yes 110 23.298 23.2Yes Data FL ge 0 4 Stroke Light FO 16.3730 14.592 Yes -8.1277 -4.384 No FL 0.17 19.22 Yes 96 16.373 16.3Yes Data FL ge 0 Not Ind. Diesel 11.9658 17.308 Yes 0.0506 10.252 Yes 1/(FL^e) 0.81 105.10 Yes 26 16.492 13.5Yes Data FL ge 0 2 Stroke Diesel 6.8337 74.147 Yes -0.0064 -4.127 No 1/(FL^e) 0.71 17.03 Yes 9 6.834 6.8Yes Data FL ge 0 2 Stroke Gas Oil 6.9302 6.932 No 0.0631 3.339 No 1/(FL^e) 0.85 11.15 No 4Yes Data FL ge 0 2 Stroke Hvy FO 13.7580 11.263 Yes -0.1069 -0.611 No 1/(FL^e) 0.02 0.37 No 22 13.758 13.7Yes Data FL ge 0 2 Stroke Int FO 18.0862 8.921 Yes -0.2595 -1.546 No 1/(FL^e) 0.23 2.39 No 10 18.086 18.0Yes Data FL ge 0 4 Stroke Diesel 9.2673 3.834 Yes -0.0543 -0.096 No 1/(FL^e) 0.00 0.01 No 14 9.267 9.2Yes Data FL ge 0 4 Stroke Gas Oil 9.6153 13.922 Yes 0.1861 20.995 Yes 1/(FL^e) 0.80 440.78 Yes 110 26.257 15.4Yes Data FL ge 0 4 Stroke Light FO 9.7439 23.720 Yes 0.1925 13.124 Yes 1/(FL^e) 0.65 172.24 Yes 96 26.966 15.8

A-6
REGRESSION SUMMARY FOR: NO2 Equivalent NOx Exponent = 1.5

A/F Loads Cycles Fuels Predic

Criteria Covered Covered Covered Intercept Int-T Sig? Coeff Coeff-T Sig? Param r2 F Sig? Obs 0.05 0.1

All Data FL ge 0 All All 32.6651 19.659 Yes -24.4322 -7.862 No FL 0.15 61.81 Yes 356 32.665 32.6All Data FL ge 0 All All 17.0581 18.481 Yes 0.1810 14.647 Yes 1/(FL^e) 0.38 214.54 Yes 356 33.250 22.7All Data FL ge 20 All All 17.5759 22.772 Yes -2.9262 -2.449 No FL 0.02 6.00 No 241 17.576 17.5All Data FL lt 20 All All 58.7960 11.209 Yes -259.2844 -5.124 No FL 0.19 26.25 Yes 115 58.796 58.7All Data FL lt 20 All All 23.1294 7.215 Yes 0.1531 6.270 Yes 1/(FL^e) 0.26 39.31 Yes 115 36.825 27.9

Yes Data FL ge 0 All All 27.6461 17.580 Yes -17.6612 -6.408 No FL 0.12 41.06 Yes 291 27.646 27.6Yes Data FL ge 0 All All 15.5247 24.154 Yes 0.1865 19.391 Yes 1/(FL^e) 0.57 376.02 Yes 291 32.207 21.4Yes Data FL ge 20 All All 16.9374 21.257 Yes -2.6760 -2.207 No FL 0.02 4.87 No 217 16.937 16.9Yes Data FL lt 20 All All 55.3881 8.753 Yes -235.5868 -4.358 No FL 0.21 18.99 Yes 74 55.388 55.3Yes Data FL lt 20 All All 18.6734 7.186 Yes 0.1744 8.884 Yes 1/(FL^e) 0.52 78.93 Yes 74 34.277 24.1Yes Data FL ge 0 Not Ind. All 30.4786 11.938 Yes -24.3023 -4.426 No FL 0.45 19.59 Yes 26 30.479 30.4Yes Data FL ge 0 2 Stroke All 15.5034 6.425 Yes 5.4192 1.239 No FL 0.03 1.54 No 45 15.503 15.5Yes Data FL ge 0 4 Stroke All 28.9309 14.654 Yes -20.0158 -5.936 No FL 0.14 35.23 Yes 220 28.931 28.9Yes Data FL ge 0 Not Ind. All 17.7773 17.308 Yes 0.0752 10.252 Yes 1/(FL^e) 0.81 105.10 Yes 26 24.502 20.Yes Data FL ge 0 2 Stroke All 18.7945 15.199 Yes -0.0539 -1.394 No 1/(FL^e) 0.04 1.94 No 45 18.794 18.7Yes Data FL ge 0 4 Stroke All 14.2911 24.437 Yes 0.2775 27.588 Yes 1/(FL^e) 0.78 761.12 Yes 220 39.113 23.0Yes Data FL ge 0 All Diesel 22.6347 11.302 Yes -11.8040 -3.572 No FL 0.21 12.76 Yes 49 22.635 22.6Yes Data FL ge 0 All Gas Oil 33.7434 9.899 Yes -30.6400 -4.675 No FL 0.16 21.86 Yes 114 33.743 33.7Yes Data FL ge 0 All Hvy FO 17.5747 4.684 Yes 3.8949 0.616 No FL 0.02 0.38 No 22 17.575 17.5Yes Data FL ge 0 All Int FO 23.3426 3.934 Yes 1.3935 0.128 No FL 0.00 0.02 No 10 23.343 23.3Yes Data FL ge 0 All Light FO 24.3249 14.592 Yes -12.0752 -4.384 No FL 0.17 19.22 Yes 96 24.325 24.3Yes Data FL ge 0 All Diesel 14.6136 13.947 Yes 0.0760 7.634 Yes 1/(FL^e) 0.55 58.28 Yes 49 21.414 17.0Yes Data FL ge 0 All Gas Oil 14.0083 13.755 Yes 0.2738 20.753 Yes 1/(FL^e) 0.79 430.69 Yes 114 38.499 22.6Yes Data FL ge 0 All Hvy FO 20.4401 11.263 Yes -0.1589 -0.611 No 1/(FL^e) 0.02 0.37 No 22 20.440 20.4Yes Data FL ge 0 All Int FO 26.8702 8.922 Yes -0.3856 -1.546 No 1/(FL^e) 0.23 2.39 No 10 26.870 26.8Yes Data FL ge 0 All Light FO 14.4763 23.720 Yes 0.2861 13.124 Yes 1/(FL^e) 0.65 172.24 Yes 96 40.062 23.5Yes Data FL ge 0 Not Ind. Diesel 30.4786 11.938 Yes -24.3023 -4.426 No FL 0.45 19.59 Yes 26 30.479 30.4Yes Data FL ge 0 2 Stroke Diesel 9.3158 39.863 Yes 1.4542 3.117 No FL 0.58 9.72 No 9 9.316 9.3Yes Data FL ge 0 2 Stroke Gas Oil 15.2591 3.353 No -6.1893 -0.572 No FL 0.14 0.33 No 4Yes Data FL ge 0 2 Stroke Hvy FO 17.5747 4.684 Yes 3.8949 0.616 No FL 0.02 0.38 No 22 17.575 17.5Yes Data FL ge 0 2 Stroke Int FO 23.3426 3.934 Yes 1.3935 0.128 No FL 0.00 0.02 No 10 23.343 23.3Yes Data FL ge 0 4 Stroke Diesel 16.8134 4.813 Yes -4.8488 -1.180 No FL 0.10 1.39 No 14 16.813 16.8Yes Data FL ge 0 4 Stroke Gas Oil 34.6129 9.822 Yes -31.7759 -4.720 No FL 0.17 22.28 Yes 110 34.613 34.6Yes Data FL ge 0 4 Stroke Light FO 24.3249 14.592 Yes -12.0752 -4.384 No FL 0.17 19.22 Yes 96 24.325 24.3Yes Data FL ge 0 Not Ind. Diesel 17.7773 17.308 Yes 0.0752 10.252 Yes 1/(FL^e) 0.81 105.10 Yes 26 24.502 20.1Yes Data FL ge 0 2 Stroke Diesel 10.1530 74.148 Yes -0.0094 -4.129 No 1/(FL^e) 0.71 17.05 Yes 9 10.153 10.Yes Data FL ge 0 2 Stroke Gas Oil 10.2959 6.932 No 0.0937 3.339 No 1/(FL^e) 0.85 11.15 No 4Yes Data FL ge 0 2 Stroke Hvy FO 20.4401 11.263 Yes -0.1589 -0.611 No 1/(FL^e) 0.02 0.37 No 22 20.440 20.4Yes Data FL ge 0 2 Stroke Int FO 26.8702 8.922 Yes -0.3856 -1.546 No 1/(FL^e) 0.23 2.39 No 10 26.870 26.8Yes Data FL ge 0 4 Stroke Diesel 13.7683 3.834 Yes -0.0807 -0.096 No 1/(FL^e) 0.00 0.01 No 14 13.768 13.7Yes Data FL ge 0 4 Stroke Gas Oil 14.2852 13.922 Yes 0.2764 20.995 Yes 1/(FL^e) 0.80 440.78 Yes 110 39.010 23.0Yes Data FL ge 0 4 Stroke Light FO 14.4763 23.720 Yes 0.2861 13.124 Yes 1/(FL^e) 0.65 172.24 Yes 96 40.062 23.5

A-6
REGRESSION SUMMARY FOR: CO Exponent = 1

A/F Loads Cycles Fuels Predic

Criteria Covered Covered Covered Intercept Int-T Sig? Coeff Coeff-T Sig? Param r2 F Sig? Obs 0.05 0.1

All Data FL ge 0 All All 17.9327 11.404 Yes -23.1061 -7.856 No FL 0.15 61.72 Yes 356 17.933 17.9All Data FL ge 0 All All -0.7044 -0.757 No 1.2802 16.633 Yes 1/(FL^e) 0.44 276.67 Yes 356 25.603 12.8All Data FL ge 20 All All 2.8330 12.807 Yes -1.4384 -4.200 No FL 0.07 17.64 Yes 241 2.833 2.8All Data FL lt 20 All All 47.6066 9.888 Yes -299.4701 -6.447 No FL 0.27 41.57 Yes 115 47.607 47.6All Data FL lt 20 All All -0.8009 -0.203 No 1.2891 6.867 Yes 1/(FL^e) 0.29 47.15 Yes 115 25.782 12.8

Yes Data FL ge 0 All All 9.9821 9.983 Yes -11.4844 -6.553 No FL 0.13 42.94 Yes 291 9.982 9.9Yes Data FL ge 0 All All 0.1548 0.323 No 0.8378 17.700 Yes 1/(FL^e) 0.52 313.29 Yes 291 16.756 8.3Yes Data FL ge 20 All All 2.7465 12.135 Yes -1.3058 -3.791 No FL 0.06 14.38 Yes 217 2.746 2.7Yes Data FL lt 20 All All 30.8036 7.784 Yes -179.5074 -5.309 No FL 0.28 28.19 Yes 74 30.804 30.8Yes Data FL lt 20 All All -0.5190 -0.218 No 0.8653 7.175 Yes 1/(FL^e) 0.42 51.48 Yes 74 17.306 8.6Yes Data FL ge 0 Not Ind. All 7.1043 4.138 Yes -7.1069 -1.925 No FL 0.13 3.71 No 26 7.104 7.1Yes Data FL ge 0 2 Stroke All 10.0714 2.787 Yes -12.2131 -1.865 No FL 0.07 3.48 No 45 10.071 10.0Yes Data FL ge 0 4 Stroke All 10.4487 9.169 Yes -12.0126 -6.172 No FL 0.15 38.09 Yes 220 10.449 10.4Yes Data FL ge 0 Not Ind. All 1.2052 2.717 No 0.3414 14.485 Yes 1/(FL^e) 0.90 209.81 Yes 26 6.828 3.4Yes Data FL ge 0 2 Stroke All -0.0311 -0.016 No 1.0290 3.637 Yes 1/(FL^e) 0.24 13.23 Yes 45 20.580 10.2Yes Data FL ge 0 4 Stroke All -0.8389 -1.956 No 1.1081 23.705 Yes 1/(FL^e) 0.72 561.94 Yes 220 22.161 11.0Yes Data FL ge 0 All Diesel 4.9827 5.218 Yes -3.4791 -2.208 No FL 0.09 4.88 No 49 4.983 4.9Yes Data FL ge 0 All Gas Oil 12.3421 5.885 Yes -16.0776 -3.988 No FL 0.12 15.90 Yes 114 12.342 12.3Yes Data FL ge 0 All Hvy FO 2.2926 1.739 No 0.7222 0.325 No FL 0.01 0.11 No 22Yes Data FL ge 0 All Int FO -0.0250 -0.338 No 1.6230 11.935 Yes FL 0.95 142.44 Yes 10 0.081 0.1Yes Data FL ge 0 All Light FO 12.9905 8.795 Yes -15.6928 -6.429 No FL 0.31 41.34 Yes 96 12.991 12.9Yes Data FL ge 0 All Diesel 1.1761 3.294 Yes 0.3111 12.743 Yes 1/(FL^e) 0.78 162.38 Yes 49 7.398 4.2Yes Data FL ge 0 All Gas Oil -1.5152 -1.755 No 1.1578 15.205 Yes 1/(FL^e) 0.67 231.19 Yes 114 23.156 11.5Yes Data FL ge 0 All Hvy FO 3.1895 3.905 Yes -0.2032 -0.755 No 1/(FL^e) 0.03 0.57 No 22 3.189 3.1Yes Data FL ge 0 All Int FO 1.1732 9.474 Yes -0.1249 -4.351 No 1/(FL^e) 0.70 18.93 Yes 10 1.173 1.1Yes Data FL ge 0 All Light FO -0.6867 -1.058 No 1.3344 13.786 Yes 1/(FL^e) 0.67 190.05 Yes 96 26.687 13.3Yes Data FL ge 0 Not Ind. Diesel 7.1043 4.138 Yes -7.1069 -1.925 No FL 0.13 3.71 No 26 7.104 7.1Yes Data FL ge 0 2 Stroke Diesel 1.6026 3.847 Yes -0.8657 -1.041 No FL 0.13 1.08 No 9 1.603 1.6Yes Data FL ge 0 2 Stroke Gas Oil 56.3283 2.555 No -89.1275 -1.701 No FL 0.59 2.89 No 4Yes Data FL ge 0 2 Stroke Hvy FO 2.2926 1.739 No 0.7222 0.325 No FL 0.01 0.11 No 22Yes Data FL ge 0 2 Stroke Int FO -0.0250 -0.338 No 1.6230 11.935 Yes FL 0.95 142.44 Yes 10 0.081 0.1Yes Data FL ge 0 4 Stroke Diesel 3.6282 5.165 Yes -1.5295 -1.851 No FL 0.22 3.43 No 14 3.628 3.6Yes Data FL ge 0 4 Stroke Gas Oil 10.3567 5.510 Yes -13.1566 -3.664 No FL 0.11 13.42 Yes 110 10.357 10.3Yes Data FL ge 0 4 Stroke Light FO 12.9905 8.795 Yes -15.6928 -6.429 No FL 0.31 41.34 Yes 96 12.991 12.9Yes Data FL ge 0 Not Ind. Diesel 1.2052 2.717 No 0.3414 14.485 Yes 1/(FL^e) 0.90 209.81 Yes 26 6.828 3.4Yes Data FL ge 0 2 Stroke Diesel 0.7511 4.762 Yes 0.0725 5.278 Yes 1/(FL^e) 0.80 27.86 Yes 9 2.201 1.4Yes Data FL ge 0 2 Stroke Gas Oil -2.3730 -1.597 No 3.6561 28.520 Yes 1/(FL^e) 1.00 813.41 Yes 4 73.122 36.5Yes Data FL ge 0 2 Stroke Hvy FO 3.1895 3.905 Yes -0.2032 -0.755 No 1/(FL^e) 0.03 0.57 No 22 3.189 3.1Yes Data FL ge 0 2 Stroke Int FO 1.1732 9.474 Yes -0.1249 -4.351 No 1/(FL^e) 0.70 18.93 Yes 10 1.173 1.1Yes Data FL ge 0 4 Stroke Diesel 1.7660 1.824 No 0.3854 0.954 No 1/(FL^e) 0.07 0.91 No 14Yes Data FL ge 0 4 Stroke Gas Oil -1.7160 -2.700 No 1.0740 19.151 Yes 1/(FL^e) 0.77 366.75 Yes 110 21.480 10.7Yes Data FL ge 0 4 Stroke Light FO -0.6867 -1.058 No 1.3344 13.786 Yes 1/(FL^e) 0.67 190.05 Yes 96 26.687 13.3

A-6
REGRESSION SUMMARY FOR: CO2 Exponent = 1

A/F Loads Cycles Fuels Predic

Criteria Covered Covered Covered Intercept Int-T Sig? Coeff Coeff-T Sig? Param r2 F Sig? Obs 0.05 0.1

All Data FL ge 0 All All 1361.0 24.928 Yes -911.9 -8.931 No FL 0.18 79.76 Yes 356 1361.0 136All Data FL ge 0 All All 653.1 20.189 Yes 46.5 17.363 Yes 1/(FL^e) 0.46 301.48 Yes 356 1582.8 111All Data FL ge 20 All All 807.0 64.326 Yes -120.6 -6.210 No FL 0.14 38.56 Yes 241 807.0 807All Data FL lt 20 All All 2361.5 14.126 Yes -10017.0 -6.211 No FL 0.25 38.57 Yes 115 2361.5 236All Data FL lt 20 All All 731.2 5.373 Yes 43.8 6.749 Yes 1/(FL^e) 0.29 45.55 Yes 115 1606.9 116

Yes Data FL ge 0 All All 1186.3 26.161 Yes -647.5 -8.148 No FL 0.19 66.38 Yes 291 1186.3 118Yes Data FL ge 0 All All 648.6 33.957 Yes 44.1 23.374 Yes 1/(FL^e) 0.65 546.34 Yes 291 1530.3 108Yes Data FL ge 20 All All 819.5 66.563 Yes -132.5 -7.072 No FL 0.19 50.02 Yes 217 819.5 819Yes Data FL lt 20 All All 2207.6 12.978 Yes 8823.5 -6.072 No FL 0.34 36.86 Yes 74 2207.6 220Yes Data FL lt 20 All All 639.4 6.831 Yes 44.5 9.365 Yes 1/(FL^e) 0.55 87.71 Yes 74 1529.4 108Yes Data FL ge 0 Not Ind. All 1228.3 11.111 Yes -684.5 -2.879 No FL 0.26 8.29 Yes 26 1228.3 122Yes Data FL ge 0 2 Stroke All 1045.2 8.284 Yes -479.9 -2.099 No FL 0.09 4.40 No 45 1045.2 104Yes Data FL ge 0 4 Stroke All 1202.2 22.388 Yes -662.2 -7.220 No FL 0.19 52.13 Yes 220 1202.2 120Yes Data FL ge 0 Not Ind. All 742.8 36.310 Yes 24.5 22.528 Yes 1/(FL^e) 0.95 507.49 Yes 26 1232.4 987Yes Data FL ge 0 2 Stroke All 667.1 9.719 Yes 35.8 3.571 Yes 1/(FL^e) 0.23 12.75 Yes 45 1382.6 102Yes Data FL ge 0 4 Stroke All 606.0 32.861 Yes 55.8 27.754 Yes 1/(FL^e) 0.78 770.29 Yes 220 1721.6 116Yes Data FL ge 0 All Diesel 1060.2 16.674 Yes -389.8 -3.715 No FL 0.23 13.80 Yes 49 1060.2 106Yes Data FL ge 0 All Gas Oil 1355.3 13.847 Yes -986.7 -5.244 No FL 0.20 27.50 Yes 114 1355.3 135Yes Data FL ge 0 All Hvy FO 939.8 23.391 Yes -302.1 -4.464 No FL 0.50 19.93 Yes 22 939.8 939Yes Data FL ge 0 All Int FO 680.3 3.872 Yes 72.7 0.225 No FL 0.01 0.05 No 10 680.3 680Yes Data FL ge 0 All Light FO 1142.9 22.495 Yes -556.0 -6.622 No FL 0.32 43.85 Yes 96 1142.9 114Yes Data FL ge 0 All Diesel 721.3 28.580 Yes 22.5 13.065 Yes 1/(FL^e) 0.78 170.71 Yes 49 1172.3 946Yes Data FL ge 0 All Gas Oil 574.8 15.544 Yes 59.5 18.240 Yes 1/(FL^e) 0.75 332.68 Yes 114 1764.2 116Yes Data FL ge 0 All Hvy FO 670.6 31.198 Yes 41.8 5.900 Yes 1/(FL^e) 0.64 34.81 Yes 22 1506.5 108Yes Data FL ge 0 All Int FO 820.3 7.151 Yes -31.8 -1.197 No 1/(FL^e) 0.15 1.43 No 10 820.3 820Yes Data FL ge 0 All Light FO 634.8 46.184 Yes 53.0 25.879 Yes 1/(FL^e) 0.88 669.74 Yes 96 1695.4 116Yes Data FL ge 0 Not Ind. Diesel 1228.3 11.111 Yes -684.5 -2.879 No FL 0.26 8.29 Yes 26 1228.3 122Yes Data FL ge 0 2 Stroke Diesel 733.4 73.288 Yes -28.2 -1.413 No FL 0.22 2.00 No 9 733.4 733Yes Data FL ge 0 2 Stroke Gas Oil 2407.9 2.562 No 2852.9 -1.277 No FL 0.45 1.63 No 4Yes Data FL ge 0 2 Stroke Hvy FO 939.8 23.391 Yes -302.1 -4.464 No FL 0.50 19.93 Yes 22 939.8 939Yes Data FL ge 0 2 Stroke Int FO 680.3 3.872 Yes 72.7 0.225 No FL 0.01 0.05 No 10 680.3 680Yes Data FL ge 0 4 Stroke Diesel 982.6 22.744 Yes -273.4 -5.378 No FL 0.71 28.92 Yes 14 982.6 982Yes Data FL ge 0 4 Stroke Gas Oil 1308.4 13.646 Yes -915.1 -4.995 No FL 0.19 24.95 Yes 110 1308.4 130Yes Data FL ge 0 4 Stroke Light FO 1142.9 22.495 Yes -556.0 -6.622 No FL 0.32 43.85 Yes 96 1142.9 114Yes Data FL ge 0 Not Ind. Diesel 742.8 36.310 Yes 24.5 22.528 Yes 1/(FL^e) 0.95 507.49 Yes 26 1232.4 987Yes Data FL ge 0 2 Stroke Diesel 710.3 143.907 Yes 1.7 3.983 Yes 1/(FL^e) 0.69 15.86 Yes 9 744.5 727Yes Data FL ge 0 2 Stroke Gas Oil 395.8 3.159 No 133.6 12.357 Yes 1/(FL^e) 0.99 152.70 Yes 4 2671.0 133Yes Data FL ge 0 2 Stroke Hvy FO 670.6 31.198 Yes 41.8 5.900 Yes 1/(FL^e) 0.64 34.81 Yes 22 1506.5 108Yes Data FL ge 0 2 Stroke Int FO 820.3 7.151 Yes -31.8 -1.197 No 1/(FL^e) 0.15 1.43 No 10 820.3 820Yes Data FL ge 0 4 Stroke Diesel 586.2 7.950 Yes 98.9 3.215 Yes 1/(FL^e) 0.46 10.34 Yes 14 2565.0 157Yes Data FL ge 0 4 Stroke Gas Oil 573.7 16.696 Yes 57.1 18.836 Yes 1/(FL^e) 0.77 354.79 Yes 110 1715.9 114Yes Data FL ge 0 4 Stroke Light FO 634.8 46.184 Yes 53.0 25.879 Yes 1/(FL^e) 0.88 669.74 Yes 96 1695.4 116

A-6
REGRESSION SUMMARY FOR: O2 Exponent = 1.5

A/F Loads Cycles Fuels Predic

Criteria Covered Covered Covered Intercept Int-T Sig? Coeff Coeff-T Sig? Param r2 F Sig? Obs 0.05 0.1

All Data FL ge 0 All All 17437.0 6.247 Yes -22996.0 -4.405 No FL 0.05 19.40 Yes 356 17437.0 1743All Data FL ge 0 All All 3007.9 1.720 No 161.2 6.886 Yes 1/(FL^e) 0.12 47.41 Yes 356 14421.9 509All Data FL ge 20 All All 2378.7 21.528 Yes 1375.3 -8.040 No FL 0.21 64.64 Yes 241 2378.7 237All Data FL lt 20 All All 47341.0 4.810 Yes -302256.0 -3.183 No FL 0.08 10.13 Yes 115 47341.0 4734All Data FL lt 20 All All 9630.8 1.513 No 130.8 2.698 No 1/(FL^e) 0.06 7.28 No 115

Yes Data FL ge 0 All All 7798.3 9.080 Yes 9141.2 -6.072 No FL 0.11 36.87 Yes 291 7798.3 779Yes Data FL ge 0 All All 1298.1 4.101 Yes 107.9 22.769 Yes 1/(FL^e) 0.64 518.42 Yes 291 10945.2 470Yes Data FL ge 20 All All 2130.4 22.334 Yes 1137.9 -7.839 No FL 0.22 61.45 Yes 217 2130.4 213Yes Data FL lt 20 All All 25276.0 7.256 Yes -152436.0 -5.122 No FL 0.27 26.24 Yes 74 25276.0 2527Yes Data FL lt 20 All All 2076.7 1.484 No 104.8 9.917 Yes 1/(FL^e) 0.58 98.34 Yes 74 9377.5 331Yes Data FL ge 0 Not Ind. All 7018.9 4.036 Yes 9675.1 -2.587 No FL 0.22 6.69 No 26 7018.9 701Yes Data FL ge 0 2 Stroke All 4761.9 9.196 Yes 4395.3 -4.683 No FL 0.34 21.93 Yes 45 4761.9 476Yes Data FL ge 0 4 Stroke All 8415.0 7.630 Yes 9864.1 -5.236 No FL 0.11 27.42 Yes 220 8415.0 841Yes Data FL ge 0 Not Ind. All 1038.3 5.831 Yes 47.2 37.143 Yes 1/(FL^e) 0.98 1379.57 Yes 26 5262.3 253Yes Data FL ge 0 2 Stroke All 1999.4 9.461 Yes 51.3 7.767 Yes 1/(FL^e) 0.58 60.33 Yes 45 6591.4 362Yes Data FL ge 0 4 Stroke All 877.2 2.897 Yes 155.1 29.779 Yes 1/(FL^e) 0.80 886.80 Yes 220 14749.4 578Yes Data FL ge 0 All Diesel 4711.8 4.819 Yes 4607.4 -2.856 No FL 0.15 8.16 Yes 49 4711.8 471Yes Data FL ge 0 All Gas Oil 10081.0 5.295 Yes -13574.0 -3.709 No FL 0.11 13.76 Yes 114 10081.0 1008Yes Data FL ge 0 All Hvy FO 4830.9 7.861 Yes 4262.3 -4.118 No FL 0.46 16.96 Yes 22 4830.9 483Yes Data FL ge 0 All Int FO 4385.2 4.346 Yes 3544.2 -1.915 No FL 0.31 3.67 No 10 4385.2 438Yes Data FL ge 0 All Light FO 7885.8 7.613 Yes 8944.3 -5.225 No FL 0.23 27.31 Yes 96 7885.8 788Yes Data FL ge 0 All Diesel 968.0 9.310 Yes 47.4 48.006 Yes 1/(FL^e) 0.98 2304.57 Yes 49 5211.2 246Yes Data FL ge 0 All Gas Oil 580.4 1.196 No 152.5 24.247 Yes 1/(FL^e) 0.84 587.90 Yes 114 13638.7 482Yes Data FL ge 0 All Hvy FO 1578.6 6.138 Yes 199.7 5.418 Yes 1/(FL^e) 0.59 29.36 Yes 22 19441.7 789Yes Data FL ge 0 All Int FO 2385.1 3.481 No 38.0 0.670 No 1/(FL^e) 0.05 0.45 No 10Yes Data FL ge 0 All Light FO 1016.8 2.438 No 177.4 11.914 Yes 1/(FL^e) 0.60 141.94 Yes 96 15869.4 561Yes Data FL ge 0 Not Ind. Diesel 7018.9 4.036 Yes 9675.1 -2.587 No FL 0.22 6.69 No 26 7018.9 701Yes Data FL ge 0 2 Stroke Diesel 4082.7 3.220 No 4183.2 -1.653 No FL 0.28 2.73 No 9Yes Data FL ge 0 2 Stroke Gas Oil 6724.9 2.253 No 8951.3 -1.262 No FL 0.44 1.59 No 4Yes Data FL ge 0 2 Stroke Hvy FO 4830.9 7.861 Yes 4262.3 -4.118 No FL 0.46 16.96 Yes 22 4830.9 483Yes Data FL ge 0 2 Stroke Int FO 4385.2 4.346 Yes 3544.2 -1.915 No FL 0.31 3.67 No 10 4385.2 438Yes Data FL ge 0 4 Stroke Diesel 1329.9 4.721 Yes -579.7 -1.749 No FL 0.20 3.06 No 14 1329.9 132Yes Data FL ge 0 4 Stroke Gas Oil 10238.0 5.173 Yes -13783.0 -3.645 No FL 0.11 13.29 Yes 110 10238.0 1023Yes Data FL ge 0 4 Stroke Light FO 7885.8 7.613 Yes 8944.3 -5.225 No FL 0.23 27.31 Yes 96 7885.8 788Yes Data FL ge 0 Not Ind. Diesel 1038.3 5.831 Yes 47.2 37.143 Yes 1/(FL^e) 0.98 1379.57 Yes 26 5262.3 253Yes Data FL ge 0 2 Stroke Diesel 1132.5 41.841 Yes 46.4 102.674 Yes 1/(FL^e) 1.00 10542.03 Yes 9 5283.6 260Yes Data FL ge 0 2 Stroke Gas Oil 1194.0 10.283 Yes 82.9 37.767 Yes 1/(FL^e) 1.00 1426.33 Yes 4 8608.3 381Yes Data FL ge 0 2 Stroke Hvy FO 1578.6 6.138 Yes 199.7 5.418 Yes 1/(FL^e) 0.59 29.36 Yes 22 19441.7 789Yes Data FL ge 0 2 Stroke Int FO 2385.1 3.481 No 38.0 0.670 No 1/(FL^e) 0.05 0.45 No 10Yes Data FL ge 0 4 Stroke Diesel 312.8 1.501 No 182.5 3.752 Yes 1/(FL^e) 0.54 14.08 Yes 14 16320.5 577Yes Data FL ge 0 4 Stroke Gas Oil 615.3 1.236 No 153.4 24.010 Yes 1/(FL^e) 0.84 576.47 Yes 110 13720.3 485Yes Data FL ge 0 4 Stroke Light FO 1016.8 2.438 No 177.4 11.914 Yes 1/(FL^e) 0.60 141.94 Yes 96 15869.4 561

A-6
REGRESSION SUMMARY FOR: HC Exponent = 1.5

A/F Loads Cycles Fuels Predic

Criteria Covered Covered Covered Intercept Int-T Sig? Coeff Coeff-T Sig? Param r2 F Sig? Obs 0.05 0.1

All Data FL ge 0 All All 8.3003 8.497 Yes -10.9026 -6.050 No FL 0.10 36.60 Yes 321 8.300 8.3All Data FL ge 0 All All 1.1654 2.036 No 0.0810 11.057 Yes 1/(FL^e) 0.28 122.26 Yes 321 7.249 2.5All Data FL ge 20 All All 0.9744 12.004 Yes -0.5558 -4.478 No FL 0.09 20.06 Yes 218 0.974 0.9All Data FL lt 20 All All 22.1000 6.861 Yes -141.1223 -4.437 No FL 0.16 19.69 Yes 103 22.100 22.All Data FL lt 20 All All 3.8756 1.846 No 0.0691 4.530 Yes 1/(FL^e) 0.17 20.52 Yes 103 6.178 2.1

Yes Data FL ge 0 All All 4.1802 6.502 Yes -5.0538 -4.513 No FL 0.07 20.37 Yes 271 4.180 4.1Yes Data FL ge 0 All All 0.3859 1.429 No 0.0667 17.064 Yes 1/(FL^e) 0.52 291.17 Yes 271 5.970 2.1Yes Data FL ge 20 All All 0.8851 11.272 Yes -0.4455 -3.762 No FL 0.07 14.16 Yes 201 0.885 0.8Yes Data FL lt 20 All All 14.0632 5.101 Yes -86.3093 -3.656 No FL 0.16 13.37 Yes 70 14.063 14.0Yes Data FL lt 20 All All 0.3131 0.265 No 0.0670 7.710 Yes 1/(FL^e) 0.47 59.45 Yes 70 5.995 2.1Yes Data FL ge 0 Not Ind. All 1.7494 3.541 Yes -2.6120 -2.321 No FL 0.21 5.39 No 22 1.749 1.7Yes Data FL ge 0 2 Stroke All 0.7667 3.957 Yes -0.3210 -0.904 No FL 0.02 0.82 No 43 0.767 0.7Yes Data FL ge 0 4 Stroke All 5.1403 6.175 Yes -6.1653 -4.388 No FL 0.09 19.25 Yes 206 5.140 5.1Yes Data FL ge 0 Not Ind. All 0.1789 1.807 No 0.0113 17.361 Yes 1/(FL^e) 0.94 301.40 Yes 22 1.010 0.3Yes Data FL ge 0 2 Stroke All 0.5473 5.503 Yes 0.0052 1.705 No 1/(FL^e) 0.07 2.91 No 43 0.547 0.5Yes Data FL ge 0 4 Stroke All 0.1150 0.543 No 0.1106 31.223 Yes 1/(FL^e) 0.83 974.85 Yes 206 9.890 3.4Yes Data FL ge 0 All Diesel 0.9475 3.450 Yes -0.9892 -2.214 No FL 0.11 4.90 No 42 0.947 0.9Yes Data FL ge 0 All Gas Oil 6.0535 4.370 Yes -8.1345 -3.055 No FL 0.08 9.33 Yes 114 6.054 6.0Yes Data FL ge 0 All Hvy FO 1.0406 4.630 Yes -0.7845 -2.046 No FL 0.19 4.19 No 20 1.041 1.0Yes Data FL ge 0 All Int FO 0.1605 0.575 No 1.3609 2.658 No FL 0.47 7.06 No 10Yes Data FL ge 0 All Light FO 4.7410 6.578 Yes -5.6510 -4.871 No FL 0.22 23.73 Yes 85 4.741 4.7Yes Data FL ge 0 All Diesel 0.0657 0.969 No 0.0110 18.455 Yes 1/(FL^e) 0.89 340.58 Yes 42 0.985 0.3Yes Data FL ge 0 All Gas Oil -0.0980 -0.301 No 0.1102 26.184 Yes 1/(FL^e) 0.86 685.59 Yes 114 9.860 3.4Yes Data FL ge 0 All Hvy FO 0.5361 4.376 Yes 0.0167 0.995 No 1/(FL^e) 0.05 0.99 No 20 0.536 0.5Yes Data FL ge 0 All Int FO 1.0607 6.147 Yes -0.0325 -2.273 No 1/(FL^e) 0.39 5.17 No 10 1.061 1.0Yes Data FL ge 0 All Light FO 0.4183 1.347 No 0.1051 9.612 Yes 1/(FL^e) 0.53 92.40 Yes 85 9.404 3.3Yes Data FL ge 0 Not Ind. Diesel 1.7494 3.541 Yes -2.6120 -2.321 No FL 0.21 5.39 No 22 1.749 1.7Yes Data FL ge 0 2 Stroke Diesel 0.2060 3.164 No -0.1509 -1.162 No FL 0.16 1.35 No 9Yes Data FL ge 0 2 Stroke Gas Oil 2.2633 2.224 No -3.4396 -1.422 No FL 0.50 2.02 No 4Yes Data FL ge 0 2 Stroke Hvy FO 1.0406 4.630 Yes -0.7845 -2.046 No FL 0.19 4.19 No 20 1.041 1.0Yes Data FL ge 0 2 Stroke Int FO 0.1605 0.575 No 1.3609 2.658 No FL 0.47 7.06 No 10Yes Data FL ge 0 4 Stroke Diesel 0.0218 2.350 No 0.0059 0.589 No FL 0.04 0.35 No 11Yes Data FL ge 0 4 Stroke Gas Oil 6.2336 4.330 Yes -8.3627 -3.041 No FL 0.08 9.25 Yes 110 6.234 6.2Yes Data FL ge 0 4 Stroke Light FO 4.7410 6.578 Yes -5.6510 -4.871 No FL 0.22 23.73 Yes 85 4.741 4.7Yes Data FL ge 0 Not Ind. Diesel 0.1789 1.807 No 0.0113 17.361 Yes 1/(FL^e) 0.94 301.40 Yes 22 1.010 0.3Yes Data FL ge 0 2 Stroke Diesel 0.0999 3.036 No 0.0017 3.023 No 1/(FL^e) 0.57 9.14 No 9Yes Data FL ge 0 2 Stroke Gas Oil 0.2000 2.820 No 0.0299 22.278 Yes 1/(FL^e) 1.00 496.29 Yes 4 2.672 0.9Yes Data FL ge 0 2 Stroke Hvy FO 0.5361 4.376 Yes 0.0167 0.995 No 1/(FL^e) 0.05 0.99 No 20 0.536 0.5Yes Data FL ge 0 2 Stroke Int FO 1.0607 6.147 Yes -0.0325 -2.273 No 1/(FL^e) 0.39 5.17 No 10 1.061 1.0Yes Data FL ge 0 4 Stroke Diesel 0.0235 2.608 No 0.0009 0.370 No 1/(FL^e) 0.02 0.14 No 11Yes Data FL ge 0 4 Stroke Gas Oil -0.0432 -0.132 No 0.1113 26.559 Yes 1/(FL^e) 0.87 705.36 Yes 110 9.956 3.5Yes Data FL ge 0 4 Stroke Light FO 0.4183 1.347 No 0.1051 9.612 Yes 1/(FL^e) 0.53 92.40 Yes 85 9.404 3.3

A-6
REGRESSION SUMMARY FOR: Dry Exhaust Mass Exponent = 1.5

A/F Loads Cycles Fuels Predic

Criteria Covered Covered Covered Intercept Int-T Sig? Coeff Coeff-T Sig? Param r2 F Sig? Obs 0.05 0.10 

All Data FL ge 0 All All 81773 6.739 Yes -103985 -4.582 No FL 0.06 21.00 Yes 356 81773.0 81773All Data FL ge 0 All All 16654 2.196 No 725 7.136 Yes 1/(FL^e) 0.13 50.92 Yes 356 64821.6 22917All Data FL ge 20 All All 13974 29.048 Yes 6660 -8.942 No FL 0.25 79.96 Yes 241 13974.0 13974All Data FL lt 20 All All 215837 5.064 Yes -1354570 -3.294 No FL 0.09 10.85 Yes 115 215837.0 21583All Data FL lt 20 All All 46871 1.699 No 586 2.788 Yes 1/(FL^e) 0.06 7.77 Yes 115 52414.7 18531

Yes Data FL ge 0 All All 38787 10.070 Yes -42156 -6.244 No FL 0.12 38.99 Yes 291 38787.0 38787Yes Data FL ge 0 All All 8982 6.390 Yes 489 23.239 Yes 1/(FL^e) 0.65 540.03 Yes 291 52701.8 24439Yes Data FL ge 20 All All 12856 30.853 Yes 5551 -8.754 No FL 0.26 76.63 Yes 217 12856.0 12856Yes Data FL lt 20 All All 118345 7.628 Yes -693710 -5.234 No FL 0.28 27.39 Yes 74 118345.0 11834Yes Data FL lt 20 All All 13054 2.103 No 473 10.086 Yes 1/(FL^e) 0.59 101.73 Yes 74 42309.6 14958Yes Data FL ge 0 Not Ind. All 35710 4.504 Yes -44675 -2.620 No FL 0.22 6.86 No 26 35710.0 35710Yes Data FL ge 0 2 Stroke All 25164 9.547 Yes -21223 -4.442 No FL 0.31 19.73 Yes 45 25164.0 25164Yes Data FL ge 0 4 Stroke All 41490 8.401 Yes -45285 -5.368 No FL 0.12 28.82 Yes 220 41490.0 41490Yes Data FL ge 0 Not Ind. All 8207 10.211 Yes 216 37.625 Yes 1/(FL^e) 0.98 1415.64 Yes 26 27522.5 15036Yes Data FL ge 0 2 Stroke All 11780 10.838 Yes 252 7.401 Yes 1/(FL^e) 0.56 54.77 Yes 45 34284.1 19736Yes Data FL ge 0 4 Stroke All 7100 5.325 Yes 700 30.514 Yes 1/(FL^e) 0.81 931.13 Yes 220 69690.4 29229Yes Data FL ge 0 All Diesel 25056 5.642 Yes -21595 -2.946 No FL 0.16 8.68 Yes 49 25056.0 25056Yes Data FL ge 0 All Gas Oil 49392 5.783 Yes -62686 -3.818 No FL 0.12 14.57 Yes 114 49392.0 49392Yes Data FL ge 0 All Hvy FO 24582 9.202 Yes -19331 -4.297 No FL 0.48 18.47 Yes 22 24582.0 24582Yes Data FL ge 0 All Int FO 21717 4.339 Yes -14896 -1.623 No FL 0.25 2.63 No 10 21717.0 21717Yes Data FL ge 0 All Light FO 38883 8.479 Yes -40817 -5.386 No FL 0.24 29.01 Yes 96 38883.0 38883Yes Data FL ge 0 All Diesel 7715 15.764 Yes 216 46.522 Yes 1/(FL^e) 0.98 2164.33 Yes 49 27070.0 14558Yes Data FL ge 0 All Gas Oil 5900 2.745 No 688 24.725 Yes 1/(FL^e) 0.85 611.34 Yes 114 61579.4 21771Yes Data FL ge 0 All Hvy FO 9835 8.921 Yes 905 5.729 Yes 1/(FL^e) 0.62 32.82 Yes 22 90791.8 38457Yes Data FL ge 0 All Int FO 13652 4.138 Yes 114 0.416 No 1/(FL^e) 0.02 0.17 No 10 13652.0 13652Yes Data FL ge 0 All Light FO 7526 4.210 Yes 811 12.697 Yes 1/(FL^e) 0.63 161.23 Yes 96 80024.7 33158Yes Data FL ge 0 Not Ind. Diesel 35710 4.504 Yes -44675 -2.620 No FL 0.22 6.86 No 26 35710.0 35710Yes Data FL ge 0 2 Stroke Diesel 20751 3.847 Yes -17801 -1.653 No FL 0.28 2.73 No 9 20751.0 20751Yes Data FL ge 0 2 Stroke Gas Oil 40881 2.327 No -52924 -1.268 No FL 0.45 1.61 No 4Yes Data FL ge 0 2 Stroke Hvy FO 24582 9.202 Yes -19331 -4.297 No FL 0.48 18.47 Yes 22 24582.0 24582Yes Data FL ge 0 2 Stroke Int FO 21717 4.339 Yes -14896 -1.623 No FL 0.25 2.63 No 10 21717.0 21717Yes Data FL ge 0 4 Stroke Diesel 10269 7.703 Yes 3880 -2.474 No FL 0.34 6.12 No 14 10269.0 10269Yes Data FL ge 0 4 Stroke Gas Oil 49800 5.609 Yes -63187 -3.725 No FL 0.11 13.88 Yes 110 49800.0 49800Yes Data FL ge 0 4 Stroke Light FO 38883 8.479 Yes -40817 -5.386 No FL 0.24 29.01 Yes 96 38883.0 38883Yes Data FL ge 0 Not Ind. Diesel 8207 10.211 Yes 216 37.625 Yes 1/(FL^e) 0.98 1415.64 Yes 26 27522.5 15036Yes Data FL ge 0 2 Stroke Diesel 8199 67.122 Yes 197 96.782 Yes 1/(FL^e) 1.00 9366.66 Yes 9 25857.0 14442Yes Data FL ge 0 2 Stroke Gas Oil 8215 13.124 Yes 489 41.328 Yes 1/(FL^e) 1.00 1707.97 Yes 4 51952.0 23678Yes Data FL ge 0 2 Stroke Hvy FO 9835 8.921 Yes 905 5.729 Yes 1/(FL^e) 0.62 32.82 Yes 22 90791.8 38457Yes Data FL ge 0 2 Stroke Int FO 13652 4.138 Yes 114 0.416 No 1/(FL^e) 0.02 0.17 No 10 13652.0 13652Yes Data FL ge 0 4 Stroke Diesel 4285 4.130 Yes 979 4.044 Yes 1/(FL^e) 0.58 16.36 Yes 14 91857.6 35246Yes Data FL ge 0 4 Stroke Gas Oil 5980 2.699 No 691 24.304 Yes 1/(FL^e) 0.85 590.69 Yes 110 61811.2 21853Yes Data FL ge 0 4 Stroke Light FO 7526 4.210 Yes 811 12.697 Yes 1/(FL^e) 0.63 161.23 Yes 96 80024.7 33158

A-6
REGRESSION SUMMARY FOR: H2O Exponent = 1

A/F Loads Cycles Fuels Predic

Criteria Covered Covered Covered Intercept Int-T Sig? Coeff Coeff-T Sig? Param r2 F Sig? Obs 0.05 0.1

All Data FL ge 0 All All 477.17 29.543 Yes -331.90 -10.987 No FL 0.25 120.72 Yes 356 477.17 477All Data FL ge 0 All All 222.44 25.956 Yes 16.49 23.250 Yes 1/(FL^e) 0.60 540.55 Yes 356 552.25 387All Data FL ge 20 All All 280.42 57.875 Yes -51.20 -6.824 No FL 0.16 46.57 Yes 241 280.42 280All Data FL lt 20 All All 825.06 18.584 Yes 3478.26 -8.121 No FL 0.37 65.94 Yes 115 825.06 825All Data FL lt 20 All All 259.05 7.286 Yes 15.20 8.966 Yes 1/(FL^e) 0.42 80.40 Yes 115 563.00 411

Yes Data FL ge 0 All All 416.44 24.781 Yes -238.44 -8.095 No FL 0.18 65.53 Yes 291 416.44 416Yes Data FL ge 0 All All 220.09 29.806 Yes 15.92 21.839 Yes 1/(FL^e) 0.62 476.93 Yes 291 538.52 379Yes Data FL ge 20 All All 284.37 56.590 Yes -53.02 -6.933 No FL 0.18 48.07 Yes 217 284.37 284Yes Data FL lt 20 All All 782.36 12.204 Yes 3163.97 -5.777 No FL 0.32 33.38 Yes 74 782.36 782Yes Data FL lt 20 All All 220.34 6.104 Yes 15.94 8.698 Yes 1/(FL^e) 0.51 75.65 Yes 74 539.05 379Yes Data FL ge 0 Not Ind. All 423.18 11.379 Yes -236.35 -2.955 No FL 0.27 8.73 Yes 26 423.18 423Yes Data FL ge 0 2 Stroke All 366.65 6.640 Yes -210.79 -2.106 No FL 0.09 4.44 No 45 366.65 366Yes Data FL ge 0 4 Stroke All 424.42 21.963 Yes -241.36 -7.312 No FL 0.20 53.47 Yes 220 424.42 424Yes Data FL ge 0 Not Ind. All 257.01 38.289 Yes 8.30 23.289 Yes 1/(FL^e) 0.96 542.37 Yes 26 423.10 340Yes Data FL ge 0 2 Stroke All 198.53 6.678 Yes 16.22 3.739 Yes 1/(FL^e) 0.25 13.98 Yes 45 522.93 360Yes Data FL ge 0 4 Stroke All 208.46 30.979 Yes 20.06 27.350 Yes 1/(FL^e) 0.77 748.01 Yes 220 609.57 409Yes Data FL ge 0 All Diesel 366.09 17.044 Yes -136.04 -3.838 No FL 0.24 14.73 Yes 49 366.09 366Yes Data FL ge 0 All Gas Oil 498.35 13.593 Yes -362.12 -5.138 No FL 0.19 26.40 Yes 114 498.35 498Yes Data FL ge 0 All Hvy FO 275.59 23.913 Yes -78.35 -4.037 No FL 0.45 16.30 Yes 22 275.59 275Yes Data FL ge 0 All Int FO 200.29 3.937 Yes 21.87 0.234 No FL 0.01 0.06 No 10 200.29 200Yes Data FL ge 0 All Light FO 380.12 23.514 Yes -190.68 -7.138 No FL 0.35 50.95 Yes 96 380.12 380Yes Data FL ge 0 All Diesel 249.71 28.157 Yes 7.61 12.542 Yes 1/(FL^e) 0.77 157.31 Yes 49 401.83 325Yes Data FL ge 0 All Gas Oil 212.09 14.629 Yes 21.80 17.051 Yes 1/(FL^e) 0.72 290.73 Yes 114 648.02 430Yes Data FL ge 0 All Hvy FO 205.72 32.352 Yes 10.86 5.181 Yes 1/(FL^e) 0.57 26.84 Yes 22 422.87 314Yes Data FL ge 0 All Int FO 242.25 7.336 Yes -9.52 -1.244 No 1/(FL^e) 0.16 1.55 No 10 242.25 242Yes Data FL ge 0 All Light FO 209.17 48.104 Yes 17.37 26.800 Yes 1/(FL^e) 0.88 718.24 Yes 96 556.66 382Yes Data FL ge 0 Not Ind. Diesel 423.18 11.379 Yes -236.35 -2.955 No FL 0.27 8.73 Yes 26 423.18 423Yes Data FL ge 0 2 Stroke Diesel 248.95 415.284 Yes 0.06 0.053 No FL 0.00 0.00 No 9 248.95 248Yes Data FL ge 0 2 Stroke Gas Oil 1003.21 2.547 No 1202.47 -1.285 No FL 0.45 1.65 No 4Yes Data FL ge 0 2 Stroke Hvy FO 275.59 23.913 Yes -78.35 -4.037 No FL 0.45 16.30 Yes 22 275.59 275Yes Data FL ge 0 2 Stroke Int FO 200.29 3.937 Yes 21.87 0.234 No FL 0.01 0.06 No 10 200.29 200Yes Data FL ge 0 4 Stroke Diesel 343.21 24.260 Yes -100.48 -6.036 No FL 0.75 36.44 Yes 14 343.21 343Yes Data FL ge 0 4 Stroke Gas Oil 475.58 13.613 Yes -328.57 -4.923 No FL 0.18 24.23 Yes 110 475.58 475Yes Data FL ge 0 4 Stroke Light FO 380.12 23.514 Yes -190.68 -7.138 No FL 0.35 50.95 Yes 96 380.12 380Yes Data FL ge 0 Not Ind. Diesel 257.01 38.289 Yes 8.30 23.289 Yes 1/(FL^e) 0.96 542.37 Yes 26 423.10 340Yes Data FL ge 0 2 Stroke Diesel 248.92 529.531 Yes 0.01 0.196 No 1/(FL^e) 0.01 0.04 No 9 248.92 248Yes Data FL ge 0 2 Stroke Gas Oil 156.49 3.046 No 56.12 12.662 Yes 1/(FL^e) 0.99 160.34 Yes 4 1122.49 561Yes Data FL ge 0 2 Stroke Hvy FO 205.72 32.352 Yes 10.86 5.181 Yes 1/(FL^e) 0.57 26.84 Yes 22 422.87 314Yes Data FL ge 0 2 Stroke Int FO 242.25 7.336 Yes -9.52 -1.244 No 1/(FL^e) 0.16 1.55 No 10 242.25 242Yes Data FL ge 0 4 Stroke Diesel 197.86 7.716 Yes 36.20 3.383 Yes 1/(FL^e) 0.49 11.44 Yes 14 921.87 559Yes Data FL ge 0 4 Stroke Gas Oil 210.71 16.687 Yes 20.68 18.560 Yes 1/(FL^e) 0.76 344.46 Yes 110 624.33 417Yes Data FL ge 0 4 Stroke Light FO 209.17 48.104 Yes 17.37 26.800 Yes 1/(FL^e) 0.88 718.24 Yes 96 556.66 382

A-6
REGRESSION SUMMARY FOR: Wet Exhaust Mass Exponent = 1.5

A/F Loads Cycles Fuels Predic

Criteria Covered Covered Covered Intercept Int-T Sig? Coeff Coeff-T Sig? Param r2 F Sig? Obs 0.05 0.10 

All Data FL ge 0 All All 82250 6.775 Yes -104317 -4.594 No FL 0.06 21.11 Yes 356 82250.0 82250All Data FL ge 0 All All 16926 2.231 No 727 7.155 Yes 1/(FL^e) 0.13 51.20 Yes 356 65019.9 22988All Data FL ge 20 All All 14254 29.641 Yes 6711 -9.014 No FL 0.25 81.25 Yes 241 14254.0 14254All Data FL lt 20 All All 216662 5.082 Yes -1358048 -3.302 No FL 0.09 10.90 Yes 115 216662.0 21666All Data FL lt 20 All All 47241 1.712 No 588 2.796 Yes 1/(FL^e) 0.06 7.82 Yes 115 52572.6 18587

Yes Data FL ge 0 All All 39204 10.141 Yes -42395 -6.257 No FL 0.12 39.15 Yes 291 39204.0 39204Yes Data FL ge 0 All All 9243 6.557 Yes 491 23.271 Yes 1/(FL^e) 0.65 541.52 Yes 291 53151.2 24767Yes Data FL ge 20 All All 13140 31.522 Yes 5604 -8.834 No FL 0.27 78.04 Yes 217 13140.0 13140Yes Data FL lt 20 All All 119128 7.655 Yes -696874 -5.242 No FL 0.28 27.47 Yes 74 119128.0 11912Yes Data FL lt 20 All All 13376 2.149 No 475 10.097 Yes 1/(FL^e) 0.59 101.95 Yes 74 42476.7 15017Yes Data FL ge 0 Not Ind. All 36133 4.536 Yes -44911 -2.622 No FL 0.22 6.87 No 26 36133.0 36133Yes Data FL ge 0 2 Stroke All 25531 9.545 Yes -21433 -4.421 No FL 0.31 19.54 Yes 45 25531.0 25531Yes Data FL ge 0 4 Stroke All 41914 8.457 Yes -45527 -5.378 No FL 0.12 28.93 Yes 220 41914.0 41914Yes Data FL ge 0 Not Ind. All 8491 10.529 Yes 217 37.678 Yes 1/(FL^e) 0.98 1419.65 Yes 26 27898.3 15352Yes Data FL ge 0 2 Stroke All 12009 10.877 Yes 254 7.368 Yes 1/(FL^e) 0.56 54.29 Yes 45 34767.4 20055Yes Data FL ge 0 4 Stroke All 7358 5.506 Yes 703 30.568 Yes 1/(FL^e) 0.81 934.41 Yes 220 70198.2 29575Yes Data FL ge 0 All Diesel 25422 5.699 Yes -21731 -2.952 No FL 0.16 8.72 Yes 49 25422.0 25422Yes Data FL ge 0 All Gas Oil 49890 5.820 Yes -63048 -3.826 No FL 0.12 14.64 Yes 114 49890.0 49890Yes Data FL ge 0 All Hvy FO 24858 9.288 Yes -19409 -4.306 No FL 0.48 18.54 Yes 22 24858.0 24858Yes Data FL ge 0 All Int FO 21917 4.337 Yes -14874 -1.605 No FL 0.24 2.58 No 10 21917.0 21917Yes Data FL ge 0 All Light FO 39264 8.541 Yes -41008 -5.398 No FL 0.24 29.14 Yes 96 39264.0 39264Yes Data FL ge 0 All Diesel 7985 16.194 Yes 217 46.390 Yes 1/(FL^e) 0.98 2152.06 Yes 49 27428.6 14859Yes Data FL ge 0 All Gas Oil 6175 2.865 Yes 691 24.758 Yes 1/(FL^e) 0.85 612.94 Yes 114 68005.0 28035Yes Data FL ge 0 All Hvy FO 10050 9.107 Yes 909 5.745 Yes 1/(FL^e) 0.62 33.01 Yes 22 91334.5 38788Yes Data FL ge 0 All Int FO 13888 4.177 Yes 110 0.400 No 1/(FL^e) 0.02 0.16 No 10 13888.0 13888Yes Data FL ge 0 All Light FO 7760 4.340 Yes 814 12.752 Yes 1/(FL^e) 0.63 162.62 Yes 96 80592.1 33510Yes Data FL ge 0 Not Ind. Diesel 36133 4.536 Yes -44911 -2.622 No FL 0.22 6.87 No 26 36133.0 36133Yes Data FL ge 0 2 Stroke Diesel 21000 3.894 Yes -17801 -1.653 No FL 0.28 2.73 No 9 21000.0 21000Yes Data FL ge 0 2 Stroke Gas Oil 41885 2.332 No -54126 -1.268 No FL 0.45 1.61 No 4Yes Data FL ge 0 2 Stroke Hvy FO 24858 9.288 Yes -19409 -4.306 No FL 0.48 18.54 Yes 22 24858.0 24858Yes Data FL ge 0 2 Stroke Int FO 21917 4.337 Yes -14874 -1.605 No FL 0.24 2.58 No 10 21917.0 21917Yes Data FL ge 0 4 Stroke Diesel 10612 7.901 Yes 3980 -2.519 No FL 0.35 6.34 No 14 10612.0 10612Yes Data FL ge 0 4 Stroke Gas Oil 50276 5.643 Yes -63516 -3.731 No FL 0.11 13.92 Yes 110 50276.0 50276Yes Data FL ge 0 4 Stroke Light FO 39264 8.541 Yes -41008 -5.398 No FL 0.24 29.14 Yes 96 39264.0 39264Yes Data FL ge 0 Not Ind. Diesel 8491 10.529 Yes 217 37.678 Yes 1/(FL^e) 0.98 1419.65 Yes 26 27898.3 15352Yes Data FL ge 0 2 Stroke Diesel 8448 69.083 Yes 197 96.674 Yes 1/(FL^e) 1.00 9345.81 Yes 9 26106.0 14691Yes Data FL ge 0 2 Stroke Gas Oil 8479 13.329 Yes 500 41.585 Yes 1/(FL^e) 1.00 1729.27 Yes 4 53202.0 24290Yes Data FL ge 0 2 Stroke Hvy FO 10050 9.107 Yes 909 5.745 Yes 1/(FL^e) 0.62 33.01 Yes 22 91334.5 38788Yes Data FL ge 0 2 Stroke Int FO 13888 4.177 Yes 110 0.400 No 1/(FL^e) 0.02 0.16 No 10 13888.0 13888Yes Data FL ge 0 4 Stroke Diesel 4511 4.293 Yes 993 4.049 Yes 1/(FL^e) 0.58 16.40 Yes 14 93343.6 35918Yes Data FL ge 0 4 Stroke Gas Oil 6250 2.812 Yes 694 24.324 Yes 1/(FL^e) 0.85 591.66 Yes 110 68301.0 28188Yes Data FL ge 0 4 Stroke Light FO 7760 4.340 Yes 814 12.752 Yes 1/(FL^e) 0.63 162.62 Yes 96 80592.1 33510

A-6
REGRESSION SUMMARY FOR: SO2

A/F Loads Cycles Fuels Prediction at 

Criteria Covered Covered Covered Intercept Int-T Sig? Coeff Coeff-T Sig? Param r2 F Sig? Obs 0.05 1.0

All Data FL ge 0 All All -0.7670 -1.669 No 2.4938 33.454 Yes Fuel S 0.79 1119.20 Yes 298 0.125 2.4All Data FL ge 20 All All 0.0724 0.239 No 2.0971 33.125 Yes Fuel S 0.84 1097.25 Yes 207 0.105 2.0All Data FL lt 20 All All 0.0202 0.016 No 2.6144 17.230 Yes Fuel S 0.77 296.87 Yes 91 0.131 2.6

Yes Data FL ge 0 All All -0.4792 -1.124 No 2.3735 28.924 Yes Fuel S 0.78 836.57 Yes 239 0.119 2.3Yes Data FL ge 20 All All 0.2349 0.730 No 2.0600 29.266 Yes Fuel S 0.83 856.49 Yes 183 0.103 2.0Yes Data FL lt 20 All All -0.2861 -0.215 No 2.6365 13.595 Yes Fuel S 0.77 184.83 Yes 56 0.132 2.6Yes Data FL ge 0 2 Stroke All -2.0526 -3.454 No 2.4836 28.628 Yes Fuel S 0.96 819.59 Yes 36 0.124 2.4Yes Data FL ge 0 4 Stroke All -0.4113 -0.877 No 2.4005 24.802 Yes Fuel S 0.75 615.13 Yes 203 0.120 2.4Yes Data FL ge 0 All Diesel -1.0787 -3.670 No 0.6258 9.525 Yes Fuel S 0.66 90.72 Yes 49 0.031 0.6Yes Data FL ge 0 All Gas Oil 0.2231 0.228 No 2.6522 3.218 Yes Fuel S 0.09 10.35 Yes 111 0.133 2.6Yes Data FL ge 0 All Hvy FO -2.0296 -2.124 No 2.4103 16.769 Yes Fuel S 0.93 281.20 Yes 22 0.121 2.4Yes Data FL ge 0 All Int FO -0.6356 -0.518 No 2.4319 16.579 Yes Fuel S 0.97 274.85 Yes 10 0.122 2.4Yes Data FL ge 0 All Light FO -3.4758 -7.517 No 2.7430 41.171 Yes Fuel S 0.95 1695.06 Yes 96 0.137 2.7Yes Data FL ge 0 Not Ind. Diesel -0.5717 -2.039 No 0.5481 9.863 Yes Fuel S 0.80 97.28 Yes 26 0.027 0.5Yes Data FL ge 0 2 Stroke Diesel 14.7217 1.918 No -4.2272 -1.899 No Fuel S 0.34 3.61 No 9Yes Data FL ge 0 2 Stroke Gas Oil 0.2575 4.072 No 0.9920 31.242 Yes Fuel S 1.00 976.09 Yes 4 0.050 0.9Yes Data FL ge 0 2 Stroke Hvy FO -2.0296 -2.124 No 2.4103 16.769 Yes Fuel S 0.93 281.20 Yes 22 0.121 2.4Yes Data FL ge 0 2 Stroke Int FO -0.6356 -0.518 No 2.4319 16.579 Yes Fuel S 0.97 274.85 Yes 10 0.122 2.4Yes Data FL ge 0 4 Stroke Diesel -1.1326 -1.275 No 0.7276 3.179 Yes Fuel S 0.46 10.11 Yes 14 0.036 0.7Yes Data FL ge 0 4 Stroke Gas Oil -0.0069 -0.007 No 3.0026 3.340 Yes Fuel S 0.10 11.16 Yes 107 0.150 3.0Yes Data FL ge 0 4 Stroke Light FO -3.4758 -7.517 No 2.7430 41.171 Yes Fuel S 0.95 1695.06 Yes 96 0.137 2.7

A-6
FIGURE A-1

PM Emission Rate Data

0.11.0

10.0

0% 20% 40% 60% 80% 100% 

Fractional Load

PM (g/kW-hr)

Lloyds (4 StrokeLloyds (2 StrokeUSCG (4 StrokeUSCG (2 Stroke

A-6
FIGURE A-2

NO Emission Rate Data

1

10

100

1000

0% 20% 40% 60% 80% 100% 

Fractional Load

NO (g/kW-hr)

Lloyds (4 StrokeLloyds (2 StrokeUSCG (4 StrokeUSCG (2 Stroke

A-6
FIGURE A-3

NOx Emission Rate Data

1

10

100

1000

0% 20% 40% 60% 80% 100% 

Fractional Load

NO

x (g/kW-hr)

Lloyds (4 StrokeLloyds (2 StrokeUSCG (4 StrokeUSCG (2 Stroke

A-6
FIGURE A-4

NO2 Emission Rate Data

1

10

100

1000

0% 20% 40% 60% 80% 100% 

Fractional Load

NO

2 (g/kW-hr)

Lloyds (4 StrokeLloyds (2 StrokeUSCG (4 StrokeUSCG (2 Stroke

A-6
FIGURE A-5

CO Emission Rate Data

0.11.0

10.0

100.0

1000.0

0% 20% 40% 60% 80% 100% 

Fractional Load

CO (g/kW-hr)

Lloyds (4 StrokeLloyds (2 StrokeUSCG (4 StrokeUSCG (2 Stroke

A-6
FIGURE A-6

CO2 Emission Rate Data

100

1000

10000

0% 20% 40% 60% 80% 100% 

Fractional Load

CO

2 (g/kW-hr)

Lloyds (4 StrokLloyds (2 StrokUSCG (4 StrokeUSCG (2 Stroke

A-6
FIGURE A-7

O2 Emission Rate Data

100

1000

10000

100000

1000000

0% 20% 40% 60% 80% 100% 

Fractional Load

O

2 (g/kW-hr)

Lloyds (4 StrokLloyds (2 StrokUSCG (4 StrokUSCG (2 Strok

A-6
FIGURE A-8

HC Emission Rate Data

0.0010.0100.1001.000

10.000

100.000

0% 20% 40% 60% 80% 100% 

Fractional Load

HC (g/kW-hr)

Lloyds (4 StrokLloyds (2 StrokUSCG (4 StrokUSCG (2 Strok

A-6
FIGURE A-9

Dry Exhaust Emission Rate Data

1000

10000

100000

1000000

0% 20% 40% 60% 80% 100% 

Fractional Load

Dry Exhaust (g/kW-hr)

Lloyds (4 StrokLloyds (2 StrokUSCG (4 StrokUSCG (2 Strok

A-6
FIGURE A-10

H2O Emission Rate Data

10

100

1000

10000

0% 20% 40% 60% 80% 100% 

Fractional Load

HO

2 (g/kW-hr)

Lloyds (4 StrokLloyds (2 StrokUSCG (4 StrokeUSCG (2 Stroke

A-6
FIGURE A-11

Wet Exhaust Emission Rate Data

1000

10000

100000

1000000

0% 20% 40% 60% 80% 100% 

Fractional Load

Wet Exhaust (g/kW-hr)

Lloyds (4 StrokLloyds (2 StrokUSCG (4 StrokUSCG (2 Strok

A-6
FIGURE A-12

NO Emission Rate Data

1

10

100

1000

0% 20% 40% 60% 80% 100% 

Fractional Load

NO (g/kW-hr)

Lloyds (gas oil)Lloyds (light fuel oil)Lloyds (intermediate fLloyds (heavy fuel oil)

A-6
FIGURE A-13

NOx Emission Rate Data

1

10

100

1000

0% 20% 40% 60% 80% 100% 

Fractional Load

NO

x (g/kW-hr)

Lloyds (gas oil)Lloyds (light fuel oil)Lloyds (intermediate fLloyds (heavy fuel oil)

A-6
FIGURE A-14

NO2 Emission Rate Data

1

10

100

1000

0% 20% 40% 60% 80% 100% 

Fractional Load

NO

2 (g/kW-hr)

Lloyds (gas oil)Lloyds (light fuel oil)Lloyds (intermediate fLloyds (heavy fuel oil)

A-6
FIGURE A-15

CO Emission Rate Data

0.11.0

10.0

100.0

1000.0

0% 20% 40% 60% 80% 100% 

Fractional Load

CO (g/kW-hr)

Lloyds (gas oil)Lloyds (light fuel oil)Lloyds (intermediate Lloyds (heavy fuel oil

A-6
FIGURE A-16

CO2 Emission Rate Data

100

1000

10000

0% 20% 40% 60% 80% 100% 

Fractional Load

CO

2 (g/kW-hr)

Lloyds (gas oil)Lloyds (light fuel oil)Lloyds (intermediate fLloyds (heavy fuel oil

A-6
FIGURE A-17

O2 Emission Rate Data

100

1000

10000

100000

1000000

0% 20% 40% 60% 80% 100% 

Fractional Load

O

2 (g/kW-hr)

Lloyds (gas oil)Lloyds (light fuel oilLloyds (intermediate Lloyds (heavy fuel o

A-6
FIGURE A-18

HC Emission Rate Data

0.010.101.00

10.00

100.00

0% 20% 40% 60% 80% 100% 

Fractional Load

HC (g/kW-hr)

Lloyds (gas oil)Lloyds (light fuel oil)Lloyds (intermediate Lloyds (heavy fuel oil

A-6
FIGURE A-19

Dry Exhaust Emission Rate Data

1000

10000

100000

1000000

0% 20% 40% 60% 80% 100% 

Fractional Load

Dry Exhaust (g/kW-hr)

Lloyds (gas oil)Lloyds (light fuel oil)Lloyds (intermediate Lloyds (heavy fuel oi

A-6
FIGURE A-20

H2O Emission Rate Data

10

100

1000

10000

0% 20% 40% 60% 80% 100% 

Fractional Load

H O (g/kW-hr) 2

Lloyds (gas oil)Lloyds (light fuel oil)Lloyds (intermediate fLloyds (heavy fuel oil

A-6
FIGURE A-21

Wet Exhaust Emission Rate Data

1000

10000

100000

1000000

0% 20% 40% 60% 80% 100% 

Fractional Load

Wet Exhaust (g/kW-hr)

Lloyds (gas oil)Lloyds (light fuel oilLloyds (intermediate Lloyds (heavy fuel oi

A-6