ASTM D6421-99a
(Test Method)Standard Test Method for Evaluating Automotive Spark-Ignition Engine Fuel for Electronic Port Fuel Injector Fouling by Bench Procedure
Standard Test Method for Evaluating Automotive Spark-Ignition Engine Fuel for Electronic Port Fuel Injector Fouling by Bench Procedure
SCOPE
1.1 This test method covers a bench test procedure to evaluate the tendency of automotive spark-ignition engine fuel to foul electronic port fuel injectors (PFI). The test method utilizes a bench apparatus equipped with Bosch injectors specified for use in a 1985-1987 Chrysler 2.2-L turbocharged engine. This test method is based on a test procedure developed by the Coordinating Research Council (CRC) for prediction of the tendency of spark-ignition engine fuel to form deposits in the small metering clearances of injectors in a port fuel injection engine (see CRC Report No. 592).
1.2 The test method is applicable to spark-ignition engine fuels, which may contain antioxidants, corrosion inhibitors, metal deactivators, dyes, deposit control additives, demulsifiers, or oxygenates, or a combination thereof.
1.3 The values stated in SI units are to be regarded as the standard. Approximate inch-pound units are shown in parentheses for information purposes only.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. Specific precautionary statements are given throughout this test method.
Note 1-If there is any doubt as to the latest edition of Test Method D 6421, contact ASTM Headquarters. Other properties of significance to spark-ignition engine fuel are described in Specification D 4814.
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An American National Standard
Designation: D 6421 – 99a
Standard Test Method for
Evaluating Automotive Spark-Ignition Engine Fuel for
Electronic Port Fuel Injector Fouling by Bench Procedure
This standard is issued under the fixed designation D 6421; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope D 5598 Test Method for Evaluating Unleaded Automotive
Spark-Ignition Engine Fuel for Electronic Port Fuel Injec-
1.1 This test method covers a bench test procedure to
tor Fouling
evaluate the tendency of automotive spark-ignition engine fuel
2.2 ANSI Standard:
to foul electronic port fuel injectors (PFI). The test method
MC 96.1 American National Standard for Temperature
utilizes a bench apparatus equipped with Bosch injectors
Measurement Thermocouples.
specified for use in a 1985-1987 Chrysler 2.2-L turbocharged
2.3 CARB Standard:
engine. This test method is based on a test procedure developed
Test Method for Evaluating Port Fuel Injector (PFI) De-
by the Coordinating Research Council (CRC) for prediction of
posits in Vehicle Engines
the tendency of spark-ignition engine fuel to form deposits in
2.4 Clean Air Act Amendment:
the small metering clearances of injectors in a port fuel
Clean Air Act Amendments of 1990, Public Law 101–549,
injection engine (see CRC Report No. 592 ).
Title 1 – Provisions for Attainment and Maintenance of
1.2 The test method is applicable to spark-ignition engine
National Air Quality Standards
fuels, which may contain antioxidants, corrosion inhibitors,
metal deactivators, dyes, deposit control additives, demulsifi-
3. Terminology
ers, or oxygenates, or a combination thereof.
3.1 Definitions of Terms Specific to This Standard:
1.3 The values stated in SI units are to be regarded as the
3.1.1 base fuel, n—unleaded automotive spark-ignition en-
standard. Approximate inch-pound units are shown in paren-
gine fuel that does not contain a deposit control additive but
theses for information purposes only.
may contain antioxidants, corrosion inhibitors, metal deactiva-
1.4 This standard does not purport to address all of the
tors, dyes, or oxygenates, or a combination thereof.
safety concerns, if any, associated with its use. It is the
3.1.2 cycle, n—a 15 s pulsing period, followed by a 50 min
responsibility of the user of this standard to establish appro-
heating period at 160°C (320°F), followed by a 10 min cool
priate safety and health practices and determine the applica-
down period.
bility of regulatory limitations prior to use. Specific precau-
3.1.3 deposit control additive, n—material added to the base
tionary statements are given throughout this test method.
fuel to prevent or remove deposits in the entire engine intake
NOTE 1—If there is any doubt as to the latest edition of Test Method
system.
D 6421, contact ASTM Headquarters. Other properties of significance to
3.1.3.1 Discussion—For the purposes of this test method,
spark-ignition engine fuel are described in Specification D 4814.
the performance of a deposit control additive is limited to the
electronic PFI tip areas.
2. Referenced Documents
3.1.4 driveability, n—the quality of a vehicle’s performance
2.1 ASTM Standards:
characteristics as perceived by the operator in response to
D 4814 Specification for Automotive Spark-Ignition Engine
changes in throttle position.
Fuel
This test method is under the jurisdiction of ASTM Committee D-2 on
Petroleum Products and Lubricants and is the direct responsibility of Subcommittee Annual Book of ASTM Standards, Vol 05.03.
5 nd th
D02.A on Gasoline and Oxygenated Fuels. Available from American National Standards Institute, 11 W. 42 St., 13
Current edition approved Dec. 10, 1999. Published January 2000.Originally Floor, New York, NY 10036.
published as D 6421–99. Last previous edition D 6421–99. Available from California Air Resources Board, P.O. Box 2815, Sacramento,
“A Program to Evaluate a Bench Scale Test Method to Determine the Deposit CA 95815. (Incorporated by reference in California Code of Regulations, Title 13,
Forming Tendencies of Port Fuel Injectors,” available from Coordinating Research Section 2257.)
Council, Inc., 219 Perimeter Ctr. Pkwy., Atlanta, GA 30346. Available from Superintendent of Documents, U.S. Government Printing
Annual Book of ASTM Standards, Vol 05.02. Office, Washington, D.C. 20402.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 6421 – 99a
3.1.5 electronic port fuel injector (PFI), n—an electrome- test procedures to obtain a correlation. The vehicle tests were
chanical device used to control fuel flow in an internal conducted as described in Test Method D 5598. The tests were
combustion engine. conducted on several base gasolines, with and without addi-
3.1.6 fouling, v—formation of carbonaceous deposits on the tives blended into these base fuels. The PFI bench test proved
pintle or metering surfaces of an electronic fuel injector, which to be reliable, repeatable, and a good predictor of PFI fouling
reduces fuel flow rate. in test vehicles.
3.1.7 pintle, n—a needle-like metering device extending 5.1.1 State and Federal Legislative and Regulatory
beyond the electronic fuel injector body that is part of an Action—Legislative and regulatory activity, primarily by the
electronic fuel injector, which controls flow rate and spray state of California (see 2.3) and the federal government (see
pattern. 2.4), necessitate the acceptance of a standard test method to
3.1.8 test fuel, n—base fuel, with or without the addition of evaluate the PFI deposit-forming tendency of an automotive
a deposit control additive, that is used for evaluation as spark-ignition engine fuel.
described in this test method. 5.1.2 Relevance of Results—The operating conditions and
design of the laboratory apparatus used in this test method may
4. Summary of Test Method
not be representative of a current vehicle fuel system. These
4.1 This test method describes a procedure for evaluating factors must be considered when interpreting results.
the formation of deposits in PFIs. The test method includes a
5.2 Test Validity:
bench test procedure that has been shown to rapidly form 5.2.1 Procedural Compliance—The test results are not con-
deposits in fuel injectors and a procedure for determining
sidered valid unless the test is completed in compliance with all
resultant flow loss. requirements of this test method. Deviations from the param-
4.2 This test method uses a simulated fuel system consisting
eter limits presented in Section 10 will result in an invalid test.
of a fuel pump, filter, pressure regulator, fuel rail, and fuel Engineering judgment shall be applied during conduct of the
injectors. A heat source is applied to the fuel injectors to
test method when assessing any anomalies to ensure validity of
simulate the hot-soak portion of the vehicle test (see Test
the test results.
Method D 5598).
4.3 Each test begins with screened injectors that are known 6. Apparatus
to foul. The tips of these four clean fuel injectors are placed in
6.1 Automatic Electronic PFI Bench Test Apparatus —This
an aluminum block. A stainless-steel internal reservoir is filled
apparatus is composed of two units, a fuel handling unit and a
with 2 L of the test fuel.
controller.
4.4 During one 60-min test cycle, the fuel injectors are
6.1.1 Fuel Handling Unit—This unit houses a machined
pulsed for 15 s, followed by a 50-min hot-soak interval in
aluminum fuel rail and a heated aluminum block designed to
which the injector aluminum block temperature controller is set
accommodate four PFIs. Heaters and thermocouples are
at a temperature of 160°C (320°F) and the fuel pressure is
mounted in the heated aluminum block. This unit also houses
regulated to 263 kPa (38 psig), followed by a 10-min cool
a 2.25-L stainless steel reservoir, an electric fuel pump, a fuel
down period. Flow measurements for each of the injectors are
regulator, and a variety of valves used to transfer fuel to and
taken at the beginning of the test, after 22 cycles, and at the end
from the reservoir and to deliver fuel under pressure to the
of the test at 44 cycles.
injectors (see Annex A1).
4.5 The change in the rate of flow for each injector from the
6.1.2 Programmable Microprocessor Controller or Other
start to the end of the test is used to determine the fouling
Controller—The controller is used to fill the fuel reservoir,
percentage of each injector.
control and measure the temperature of the heated block, pulse
the injectors, control the soak period, count the number of test
5. Significance and Use
cycles, and control the flow period for the measuring of the
5.1 Driveability problems in PFI automobiles were first
flow rate. The unit is programmed to shut down automatically
reported in 1984. Deposits are prone to form on the metering
at the end of each 22-cycle period.
surfaces of pintle type electronic fuel injectors. These deposits
6.1.3 External Pressure Regulator—This regulator is used
reduce fuel flow through the metering orifices. Reductions in
to adjust the pressure of the nitrogen gas on the fuel system.
metered fuel flow result in an upset in the air-fuel ratio, which
This ensures that the pressure of the fuel in the fuel rail is
can affect emissions and driveability. When heavy enough,
maintained with an accuracy of 6 6.8 kPa (6 1.0 psi) during
these deposits can lead to driveability symptoms, such as
the test.
hesitation, hard starting, or loss of power, or combination
6.1.4 Electronic PFIs—Only Bosch EV1.1A (Part Number
thereof, that are easily noticed by the average driver and that 9
0280150360) pintle-style injectors shall be used. The corre-
lead to customer complaints. The mechanism of the formation
sponding Chrysler Corp. part number is 4306024 and is clearly
of deposits is not completely understood. It is believed to be
marked on the injector. The protective cap shall be removed
influenced by many factors, including driving cycle, engine
and injector design, and composition of the fuel. The procedure
in this test method has been found to build deposits in PFIs on
The following instrument has been found suitable by interlaboratory coopera-
a consistent basis. This procedure can be used to evaluate
tive testing: Port Fuel Injector Bench Test Apparatus. Available from Southwest
differences in base fuels and fuel additives. A study of PFI
Research Institute, San Antonio, TX.
9 th
fouling was conducted in both the bench test and the vehicle Available from Robert Bosch Corp., 25 Ave., Broadview, IL 60153.
D 6421 – 99a
from the injector by cutting the plastic cap with a razor blade built up in the injectors. This cleaner or any other carburetor or
and gently heating with a heat gun. The rubber o-rings and engine parts cleaner that is proven effective in removing such
spacers shall be removed to expose the bare metal injector tip. deposits shall be used to clean the injectors. (Warning—
Each injector shall be screened for fouling capability prior to Berryman Chem-Dip contains methylene chloride, monochlo-
use in the procedure. The screening procedure is found in rotoluene, xylene, ethyl phenols, and xylenols that are ex-
Annex A2. tremely dangerous if inhaled, are skin irritant on contact, and
6.2 Testing Area—The ambient atmosphere of the testing are carcinogenic.)
area shall be reasonably free of contaminants. The temperature
7.3 Rinsing Solvent—A 1:1 mixture of isooctane and xy-
should be maintained at 24 65°C (75 69°F). Uniform tem-
lene, or suitable mixture of solvents, shall be used to rinse the
perature is necessary to ensure repeatable injector flow mea-
bench test apparatus reservoir, injectors, and fuel lines between
surements. The specific humidity shall be maintained at a
tests. Approximately 1 L is used.
uniform comfortable level. (Warning—Provide adequate ven-
7.4 Test Fuel—A test fuel is either a base fuel or a
tilation and fire protection in areas where flammable or volatile
homogeneous blend of additives and base fuel. A single batch
liquids and solvents, or both, are used. Suitable protective
shall be blended before the start of the test. Approximately 8 L
clothing is recommended.
(2 gal) of fuel is needed for a single test.
6.3 Laboratory Equipment:
7.5 Additive/Base Fuel—Some test requestors may require
6.3.1 Analytical Balance—An analytical balance capable of
that the test fuel be blended at the test laboratory and, therefore,
0.01 g resolution with a maximum capacity of at least 200 g is
will supply the deposit control additive and may, at their option
recommended. The balance should be calibrated following the
or if a suitable base fuel is not available at the test laboratory,
manufacturer’s procedure and frequency recommendations.
supply untreated base fuel. The test requestor shall supply the
6.3.2 Graduated Cylinders—Four graduated cylinders of 50
deposit control additive and, if supplied, the base fuel in
or 100 mL capacity, accurate to the nearest millilitre are
appropriate volumes and packaging to ensure safe and efficient
recommended for use in flow testing.
handling. Blending instructions detailing the concentration
6.3.3 Low Voltage Power Supply—A 12 V, variable, direct
ratio either volumetric-based or mass-based shall accompany
current power source should be used in cleaning of the
all deposit control additives. Mass-based measurement is
injectors.
preferred. The blended fuel shall be clearly identified.
6.3.4 Ultrasonic Bath—An ultrasonic bath with heating
7.5.1 Additive/Base Fuel Shipment and Storage—The addi-
capabilities should be used for the cleaning of the injectors.
tive shall be shipped in a container as dictated by safety and
6.3.5 Pipette Bulb—A pipette bulb should be used to draw
environmental regulations. The additive shall be stored in
injector cleaning solution into the injector for cleaning.
accordance with all applicable safety and environmental regu-
6.3.6 Pipette—A disposable transfer pipette should be used
lations.
to fill injectors with the cleaning solution during the cleaning
7.5.2 Base Fuel—The base fuel used for this test method
procedure.
should be typical of commercial, automotive spark-ignition
6.3.7 Plastic Disposable Beakers—Disposable plastic bea-
engine fuel. The base fuel may contain oxygenates typical of
kers of approximately 150 mL or other containers of equivalent
those being used commercially.
size should be used to contain the injector cleaning fluid during
7.6 Nitrogen Gas
...
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