ARBjunrpt September 30, 1998

SCAQMD Contract No: 98108

 ARB LPG Fuel Blends Evaluation Project

June 1998 Progress Report

 submitted to:

 ARB LPG Fuel Blends Evaluation Project Task Group

American Automobile Manufacturers Association, ARCO Products Company, California Air Resources Board, Cummins Engine Company, Engine Manufacturers Association, Equilon, Ford Motor Company, GFI, IMPCO, National Propane Gas Association, Natural Resources Canada, Railroad Commission of Texas Alternative Fuels Research & Education Division, South Coast Air Quality Management District, Western States Petroleum Association


  1. Executive Summary

Emissions testing continued at ORTECH Corporation (ORTECH). Emissions test results, total hydrocarbon (THC) speciation, and non-methane organic gases (NMOG) analysis were completed for each of the test and certification fuels (see Table 1). ADEPT continues to coordinate with Cummins Engine Co. (Cummins) and ORTECH on technical questions and issues. Dixie Services, Inc. (Dixie) completed the fuel properties and octane testing and submitted final results in early June. Light-duty truck (Ford F150 Bi-Fuel) emissions tests at ARB Haagen Smit Laboratory (ARB-El Monte) continued throughout June. Proposals for performance and combustion testing were received and test protocol refinements continued throughout the month.

 The certification and test fuel blends have the following components:

 Table 1: Testing Fuel Blend Content at ORTECH

Fuel Name

Propane Content

Propylene Content N-Butane Content
Certification Fuel 94.42% 3.68% 1.90%
Test Fuel #1 85.28% 9.86% 4.86%
Test Fuel #2 81.15% 14.15% 4.70%
Test Fuel #3 80.07% 9.97% 9.96%
Test Fuel #4 76.34% 3.78% 19.88%
 II. Test Program Work Performed


  1. Fuel Properties and Octane Testing

Testing of the fuel blends at Dixie was finalized in May. See Table 2 for the octane test results and comparison.

 Table 2: Octane Test Results for LPG Blends

  Octane Results
Base Fuel 108.4 96.1 102.3
Test Fuel #1 107.7 94.6 101.2
Test Fuel #2 106.6 93.7 100.2
Test Fuel #3 107.0 94.1 100.6
Test Fuel #4 106.8 94.4 100.6
 In general, a higher octane number means the engine can run more efficiently and will have less tendency to knock. The Research Octane Number (RON) is obtained in a single cylinder laboratory engine. The Motor Octane Number (MON) is obtained in a more widely representative test engine. Because engine designs vary greatly, neither RON nor MON is very accurate in depicting on-road engine behavior in the average engine. The Anti-Knock Index (AKI) is the average of RON and MON. AKI is usually the best representation of the fuel's actual on-road octane number (rather than either RON or MON).


  1. Medium-Duty Engine (Cummins B5.9LPG) Emissions Tests at ORTECH.

Emissions testing continued at ORTECH. Two test runs were completed for each test fuel, and six runs were conducted using certification fuel. Each run consisted of one cold and three hot starts. Emissions test results, THC speciation, and NMOG analyses were completed (see attached). Ozone forming potential results will be available in July.

 ARB staff and the Task Group began to evaluate the data. Per the project MOU, test fuels can continue to later tests if their emissions are "equivalent or better than the base fuel". For each emission type, the criteria for determining whether the candidate fuel is equivalent to the base fuel is:

 Xc = Xr(1+2d)

 Xc is the average composite emissions during testing with the candidate fuel.

Xr is the average composite emissions during testing with the reference fuel

d is the coefficient of variability (CoV).

 The CoV is calculated using the same methodology used in the Auto/Oil Air Quality Improvement Research Program.

 At the project outset, Coefficients of Variability were determined for each of the emissions types. The medium-duty CoVs were originally estimated from data in a SwRI report titled Reactivity Comparison of Exhaust Emissions from Heavy-Duty Engines Operating on Gasoline, Diesel, and Alternative Fuels, and were further supported with other ARB heavy-duty engine test data, and supplemented by discussions with Cummins and ORTECH representatives. The CoVs will be reviewed once actual ARB certified LPG dedicated engine data becomes available.

 Another set of CoVs was determined from the project emissions data. Discussion is ongoing within the Task Group as to whether the predetermined CoVs, the project data CoVs, or a combination of both, should be used in the Xc calculations which will lead to the selectionof fuels for further testing.

 According to the preliminary and partial results compiled to date by ORTECH, and using the CoVs generated by the project emissions tests, test fuels #1 and #2 have emissions levels that may pass. Fuels #3 and #4 do not appear to pass. Final decisions on which fuels will continue to the performance/combustion phase will be made after all results from both light and medium duty emissions tests are available.

 On June 29, 1998, The Technical Advisory Committee (TAC) authorized amendments to the ORTECH emissions testing contract (Amendment Authorizations #2 and #3) which increased the contract and scope of the work as follows:

  1. Amendment #2 authorized an additional $1,000 for a baseline transient emission test on certification fuel after completion of the tests on fuel #2. The Task Group requested more data points on certification fuel, interspersed with the test fuel runs, to verify that the emissions results weren't drifting over time. Such tests would determine if the test engine was producing consistent results over time.
  2. Amendment #3 authorized an additional $2,500 for a transient emissions test on test fuel #2. The additional tests will be performed in early July. These test runs will provide additional data points, statistically strengthening conclusions drawn from the emissions tests.


  1. Light-Duty Truck (F150 Bi-Fuel) Emissions Tests at ARB Haagen Smit Laboratory

Testing began at ARB-El Monte on May 27th. Test runs performed during the last week of May and first week of June were invalidated because the Ford F150 Bi-Fuel engine was calibrated with the wrong chassis dynamometer coefficient. Testing resumed June 16th and 17th with two successful runs on certification fuel. The next run, scheduled for June 23rd, was aborted because of power loss in the ARB-El Monte lab. Tests are scheduled for July on a daily basis.


  1. Performance / Combustion and Durability Tests

Proposals were initially solicited from five laboratories: Colorado School of Mines (CIFER), Cummins, ORTECH, Southwest Research Institute (SwRI), and the University of California Riverside Research Center (CE-CERT). CIFER and CE-CERT declined to provide final proposals.

 The goal of the performance / combustion testing protocol refinements was to get the most meaningful results for the least cost. The testing protocol was refined to best meet this goal with input from Task Group members, the TAC, and the candidate laboratories. The laboratories are updating their proposals and cost estimates to reflect the modified protocol. Once proposals are finalized, a laboratory will be selected in July. The present version of the protocol calls for the following parameters to be measured:

Engine speed Exhaust temperatures (all cylinders)

Engine torque Engine exhaust backpressure

Air flow Fuel flow

Engine blow-by Intake air temperature

Boost temperature In-cylinder peak pressure

Boost pressure Fuel temperature

Intake air pressure Fuel supply pressure

Barometer reading Test cell ambient humidity

Parameters to be calculated are as follows:

Engine power Coefficient of variance (CoV)

Equivalence ratio (lambda) Brake specific fuel consumption (BSFC)

Mass fraction burned In-cylinder pressure rate of rise

Brake thermal efficiency Combustion duration

Rate of combustion Heat release rate

Tendency to misfire Tendency to knock (knock index)

Ignition evaluation at full load Power and torque map (at max torque, max power, and rated speed)


  1. Project Management Support and Administrative Work Performed

 A. Project Fundraising

ADEPT submitted a funding proposal to Chevron and continued to follow up with proposals submitted in May to Exxon and Tosco. The Engine Manufacturers Association (EMA), Chevron, and Exxon declined to fund the project. ADEPT began preparing a Propane Research and Education Council (PERC) funding proposal. The present project shortfall is estimated at $150,000. As the project progresses and actual project costs become more certain, the shortfall and budget figures will change.


  1. Project Expenditures

The table below shows June expenditures and total expenditures to date.



Funds Expended

In June
Total Funds Expended
Fuel (Aeriform)



Emissions Tests (ORTECH)



Fuel Properties (Dixie)






Attorney Fees












 Project Account Balance as of June 30, 1998: $74,282.97

 Total funds received to date, by funder source, are:















 C. Project Contracts and Other Documents

ADEPT has received all of the signatures for filing of the MOU except for Cummins. The original signatures have been submitted to ARB. The NPGA, PGAC, SCAQMD, Shell, WPGA funding contracts have been completed. The AFRED, ARB, ARCO, Cummins and Ford contracts are all in various stages of completion. The Disclosure of Joint Research Venture Filing is being finalized. NRCan did not wish to be named in the filing because they are a foreign agency. However, they agreed to have a contact name included in the filing for reference.

 The first monthly progress report (April 1998) was finalized and distributed to all project partners and interested partners.

 Travel associated with effort described:.

6/21/98 ADEPT travel to ARB and WPGA offices.

 II. Work planned for the next reporting period (July 1 - 31, 1998)

 Project Management-ADEPT

    1. ADEPT will continue general project management.
    2. ADEPT will prepare and complete funding contracts and letters of agreement for co-sponsors.
    3. ADEPT will continue fundraising.
    4. ADEPT will review proposals for performance/combustion tests and recommend a lab for testing.

 Test Program

    1. ORTECH: Continue emissions testing.
    2. ORTECH will begin preparation of final report.
    3. ARB will continue emissions tests.
    4. Selected laboratory will prepare for performance and combustion testing.

 III. Attachments:

    1. Project Timeline (GANTT Chart).
    2. ORTECH Weekly/Interim reports (with mailed version).
    3. ORTECH Contract Ammendments

 IV. Disclaimer

This report was prepared by The ADEPT Group, Inc. (ADEPT) as a result of work co-sponsored by the South Coast Air Quality Management District (SCAQMD) and Task Group Members. The opinions, findings, conclusions, and recommendations are those of the author and do not necessarily represent the views of SCAQMD. SCAQMD, their officers, employees, contractors, and subcontractors make no warranty, expressed or implied, and assume no legal liability for the information in this report. SCAQMD has not approved or disapproved this report, nor have they passed upon the accuracy or adequacy of the information contained herein.

 V. Glossary of Acronyms

 AKI anti-knock index

ARB California Air Resources Board

ASTM American Society for Testing and Materials

bhp brake horse power

BSFC brake specific fuel consumption

C Celsius

CE-CERT University of California Riverside Research Center

CO carbon monoxide

CO2 carbon dioxide

CoV Coefficient of Variation

EMA Engine Manufacturers Association

F fahrenheit

g/bhp/hr grams/brake horse power/hour

Hg mercury

kPa kilopasquals

lb.-ft. pound feet

LPG liquefied petroleum gases

MON motor octane number

NMHC non-methane hydrocarbons

NPGA National Propane Gas Association

NOx oxides of nitrogen

psig pounds per square inch of gas

ppm parts per million

RON research octane number

rpm revolutions per minute

SCAQMD South Coast Air Quality Management District

SwRI Southwest Research Institute

TAC Technical Advisory Committee

THC total hydrocarbons

WPGA Western Propane Gas Association