ASTMs Subcommittee D02.A Maintains Spark-Ignition Engine Fuel
by Ben Bonazza and Lew Gibbs
One standard can be a big responsibility, especially when it specifies
a product that is environmentally sensitive, is used by millions
in the United States, and is heavily regulated. Subcommittee D02.A
works throughout the year to maintain not only this standard on
spark ignition engine fuel (that is, the gas in your car), but
many others as well.
Subcommittee D02.A on Gasoline and Oxygenated Fuels has the primary task of developing
and maintaining specifications to insure the quality of gasoline
sold in the United States. More recently, the subcommittee has
broadened this task to include the development of specifications
for oxygenates (the gasoline blending components which are added
to make todays cleaner-burning, reformulated gasolines), and
for alcohol fuels, which contain predominately ethanol and methanol.
Today, the work of the subcommittee is changing, requiring harmonization
with the efforts of regulatory agencies, such as the U.S. Environmental
Protection Agency and the California Air Resources Board. This
harmonization is required during the development of standards
and also in determining the appropriate use of standards in writing
Who We Are
Subcommittee D02.A is a group of diverse, mainly technical, individuals
whose primary interest is the quality of automotive fuels for
ground-based spark-ignition engines. We have 139 voting members
and 109 non-voting members for a total membership of 248. The
voting membership breakdown is as follows:
63 producers (45%),
67 general interest (48%),
Eight users (6%), and
One consumer (<1%).
Producers are mainly represented by the integrated petroleum companies,
ethanol producers, and pipeline companies, whereas the users are
represented by the auto manufacturers and their suppliers. The
general interest members include state and federal regulators,
independent laboratories, and consultants. Although the subcommittee
is in balance according to ASTM regulations (producers < general
interest + users + consumers), it is obvious that it contains
a disproportionately large number of producers relative to users.
Our automotive members expressed considerable concern over this
voting imbalance, and ASTMs Committee on Standards expressed
similar concern. This forced the subcommittee into action and
a balanced voting system (BVS) was developed, with ASTMs approval.
The BVS gave each voting bloc an equal vote. The new voting system
is compared with the standard ASTM voting system in Figure 1. The imbalance issue resulted in the departure of all but one
of our automotive representatives (Honda) in 1997, just six months
before the new voting system was approved and put into effect
(Figure 2). The lack of sufficient user representation often makes it difficult
to address the user position in building consensus standards.
What We Do
As is clearly defined in our scope, the duties of the subcommittee
include 1) developing specifications, 2) developing test procedures,
and 3) developing information on spark-ignition engine fuels.
Figure 3 lists items in each of these categories under the jurisdiction
of Subcommittee D02.A. Of these, unquestionably the most important
and the one the subcommittee spends the most time on is the U.S.
gasoline specification, D 4814, Specification for Automotive Spark-Ignition Engine Fuel. This
specification is used by refiners, gasoline marketers, state and
federal government agencies, shippers, and pipeline operators
to specify product properties for exchange and sale. Further,
many foreign gasoline specifications are based on D 4814. The
specification describes important performance characteristics
of automotive fuels, such as volatility, lead content, copper
corrosion, solvent-washed gum, sulfur content, oxidation stability,
water tolerance, and driveability index. Although D 4814 covers
gasoline blends with oxygenates, such as alcohols and ethers,
it does not cover fuels that contain an oxygenate as the primary
component. These alternative fuels, fuel methanol (M85) and
fuel ethanol (Ed85), are covered by their respective specifications, D 5797 and D 5798. The subcommittee also has developed and maintains specifications
for the oxygenates commonly added to gasoline, ethanol (D 4806) and methyl tert-butyl ether (MTBE, D 5983).
Subcommittee D02.As test methods, also shown in Figure 3, include
tests developed to measure intake valve deposits (IVD) and port
fuel injector (PFI) deposits, commonly formed in spark-ignition
engines. Recently, newer replacement IVD and PFI test methods
have been developed (D 6201 and D 6421). The water tolerance test (D 6422) was developed to measure the ability of a fuel to dissolve water
without phase separation, a property that is critical for gasoline-alcohol
blends. Finally, D 6423 was developed at the request of General Motors to detect highly
acidic ethanol in the field. Acidic ethanol can cause corrosion
of fuel system components.
Along with specifications and test methods, Subcommittee D02.A
also develops information to educate people in the area of fuels.
Many of our specifications provide educational information. D
4814 provides a wealth of information in its appendices, including
EPA rules relating to fuel volatility, lead and phosphorous contents,
deposit control additive certification, and use of oxygenates
in blends with unleaded gasoline.
However, Subcommittee D02.A has one document developed strictly
for educational purposes. This is Research Report D02-1347, Research
Report on Reformulated Spark-Ignition Engine Fuel (see Figure 3 and the article on this subject). This document is designed to provide comprehensive and detailed
information on federal and state requirements for reformulated
gasoline to be used in ground vehicles equipped with spark-ignition
engines. The most valuable aspect of this document is that the
subcommittees Reformulated Gasoline Task Force constantly updates
it, so the information is always current.
How We Are Organized
Subcommittee D02.A is organized into four sections, a Balanced
Technical Advisory Panel (BTAP) and a number of task groups, as
shown in Figure 4. The Specifications and Volatility Sections, with their task
groups, carry out the majority of the subcommittees work. The
Specifications Section, as the name indicates, keeps the subcommittees
many specifications current, and addresses new concerns that come
to light relative to them. Because volatility is such an important
gasoline property, we have a separate section, the Volatility
Section, to deal with these issues.
The BTAP was established during the development of the balanced
voting system process. It is a special panel that reviews data
on highly contentious issues and evaluates the ideas technical
merit. Based on its evaluation, the BTAP will either recommend
that the subcommittee adopt a proposal or it will recommend that
the supporters of the proposal develop additional and more convincing
data before bringing the issue before the subcommittee. The BTAPs
recommendation is not binding, and any proposal may be brought
directly to the subcommittee without BTAPs approval.
Our Work with Regulatory Agencies
Before the federal government began controlling maximum vapor
pressure in 1989 under its Phase I program, there was little federal
influence on Specification D 4814. As a result of the Clean Air
Act Amendments of 1990, there have been major adjustments to D
4814. Figure 5 shows what properties are under the influence of federal regulations
and which are still the prerogatives of ASTM. D 4814 has incorporated
all of the federal vapor pressure regulations, which are only
in effect in summer, in eight new tables. In winter, the limits
revert back to the original specification D 4814 limits. An appendix
discusses all of the other federal limits. As mentioned earlier,
Subcommittee D02.As research report on reformulated gasoline
provides comprehensive and detailed information on federal and
state requirements of reformulated gasoline for ground vehicles
equipped with spark-ignition engines. Maintaining these documents
requires close cooperation with the regulatory agencies.
When the California Air Resources Board staff held workshops to
develop the California Phase 3 reformulated gasoline program,
Subcommittee D02.A representatives participated in the development
of the states specification for ethanol. The state uses specification
D 4806 as an integral part of their specification. The state of
Californias additional property requirements are shown in an
appendix of specification D 4806 along with future federal requirements.
The introduction of these additional property limits into D 4806
will be considered in the future when the regulations become effective.
Intake valve deposit test method D 5500 and port fuel injector deposit test method D 5598 are specified as part of the federal and state of California
gasoline deposit control additive certification processes. Subsequently,
Subcommittee D02.A, in conjunction with the Coordinating Research
Council (CRCan independent organization that directs studies
on the interaction of automotive equipment and petroleum products),
has developed new replacement procedures, Test Methods D 6201
and D 6421. Subcommittee D02.A is working with other stakeholders
(the Alliance of Automobile Manufacturers, the American Chemistry
Council, and the American Petroleum Institute) to develop a proposal.
It will be for the adoption by the Environmental Protection Agency
of the new engine deposit test methods and the acceptance of the
latest versions of the original deposit test methods.
Our Recent Accomplishments
The standard specifications and test methods of Subcommittee D02.A
are living documents. The goal to keep specification D 4814 current
with federal specifications requires considerable attention and
balloting of revisions. Table 1 summarizes the chronological changes made to D 4814 since 1995.
Every year some change has been made in response to federal regulation
changes. Changes were also made to ensure better performance of
gasoline. The most important of these occurred in 1998 when a
driveability index (DI) system was incorporated in D 4814, which
ensured for each volatility class good cold-start and warm-up
performance of gasoline-powered vehicles. Currently under ballot
is the addition of a second DI limit at the point of sale.
Similarly, changes were made to specification D 4806 to keep it
current. An important recent change as mentioned earlier was the
development of test method D 6423 and the addition of a limit
to control the acid strength of ethanol used in blends with gasoline
to protect fuel system components. The same action was taken for
specification D 5798.
Changes have been made as necessary to the various test methods
developed by Subcommittee D02.A to keep them viable.
Our Current Activities
Subcommittee D02.A has a number of projects currently under way
to maintain and improve its specifications and test methods. To
better control the properties of products, new and improved test
methods are required. Subcommittee D02.A works closely with the
various Committee D02 property subcommittees. Current needs are
for test methods to determine low levels of volatile silicon compounds,
very low levels of lead, particulate contamination and improved
test methods for determining stability. The subcommittee also
participates in interlaboratory studies to help develop precision
statements for test methods. Currently in progress is an interlaboratory
study to determine the precision of test method D 6422. Subcommittee
D02.A also works with outside organizations, such as the CRC.
Current projects with the CRC involve determining the impact of
blending ethanol on DI and driveability and on hot-fuel-handling
performance in modern fuel-injected vehicles.
Subcommittee D02.A consists of members with diverse interests.
It is an active group with many specifications and test methods
to develop and maintain relating to fuels used in ground vehicles
powered by spark-ignition engines. Many of the fuel properties
are now controlled by federal and state emissions regulations.
This complicates the groups responsibility to provide high-performing
fuels, but Subcommittee D02.A is up to this task. //
Copyright 2002, ASTM