ASTM D6421-99a(2014)
(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
SIGNIFICANCE AND USE
5.1 Driveability problems in PFI automobiles were first reported in 1984. Deposits are prone to form on the metering surfaces of pintle-type electronic fuel injectors. These deposits reduce fuel flow through the metering orifices. Reductions in metered fuel flow result in an upset in the air-fuel ratio, which can affect emissions and driveability. When heavy enough, these deposits can lead to driveability symptoms, such as hesitation, hard starting, or loss of power, or a combination thereof, that are easily noticed by the average driver and that lead to customer complaints. The mechanism of the formation of deposits is not completely understood. It is believed to be 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 a consistent basis. This procedure can be used to evaluate differences in base fuels and fuel additives. A study of PFI fouling was conducted in both the bench test and the vehicle test procedures to obtain a correlation. The vehicle tests were conducted as described in Test Method D5598. The tests were conducted on several base gasolines, with and without additives blended into these base fuels. The PFI bench test proved to be reliable, repeatable, and a good predictor of PFI fouling in test vehicles.
5.1.1 State and Federal Legislative and Regulatory Action—Legislative and regulatory activity, primarily by the state of California (see 2.3) and the federal government (see 2.4), necessitate the acceptance of a standard test method to evaluate the PFI deposit-forming tendency of an automotive spark-ignition engine fuel.
5.1.2 Relevance of Results—The operating conditions and design of the laboratory apparatus used in this test method may not be representative of a current vehicle fuel system. These factors must be considered when interpreting results.
5.2 Test Validity:
5.2.1 Procedural Compliance—The test ...
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).2
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 D6421, contact ASTM International Headquarters. Other properties of significance to spark-ignition engine fuel are described in Specification D4814.
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Designation: D6421 − 99a (Reapproved 2014)
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 D6421; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
1.1 This test method covers a bench test procedure to 2.1 ASTM Standards:
evaluate the tendency of automotive spark-ignition engine fuel D4814Specification for Automotive Spark-Ignition Engine
to foul electronic port fuel injectors (PFI). The test method Fuel
utilizes a bench apparatus equipped with Bosch injectors D5598Test Method for Evaluating Unleaded Automotive
specified for use in a 1985-1987 Chrysler 2.2-L turbocharged Spark-IgnitionEngineFuelforElectronicPortFuelInjec-
engine.Thistestmethodisbasedonatestproceduredeveloped tor Fouling
by the Coordinating Research Council (CRC) for prediction of 2.2 ANSI Standard:
the tendency of spark-ignition engine fuel to form deposits in MC96.1AmericanNationalStandardforTemperatureMea-
the small metering clearances of injectors in a port fuel surement Thermocouples
2 5
injection engine (see CRC Report No. 592). 2.3 CARB Standard:
Test Method for Evaluating Port Fuel Injector (PFI) Depos-
1.2 The test method is applicable to spark-ignition engine
its in Vehicle Engines
fuels, which may contain antioxidants, corrosion inhibitors,
2.4 Clean Air Act Amendment:
metal deactivators, dyes, deposit control additives,
Clean Air Act Amendments of 1990, Public Law 101–549,
demulsifiers, or oxygenates, or a combination thereof.
Title 1 –Provisions for Attainment and Maintenance of
1.3 The values stated in SI units are to be regarded as the
National Air Quality Standards
standard. Approximate inch-pound units are shown in paren-
3. Terminology
theses for information purposes only.
1.4 This standard does not purport to address all of the 3.1 Definitions of Terms Specific to This Standard:
3.1.1 base fuel, n—unleaded automotive spark-ignition en-
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- gine fuel that does not contain a deposit control additive but
may contain antioxidants, corrosion inhibitors, metal
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use. Specific precau- deactivators, dyes, or oxygenates, or a combination thereof.
tionary statements are given throughout this test method.
3.1.2 cycle, n—a 15-s pulsing period, followed by a 50-min
heating period at 160°C (320°F), followed by a 10-min
NOTE 1—If there is any doubt as to the latest edition of Test Method
cool-down period.
D6421, contact ASTM International Headquarters. Other properties of
significance to spark-ignition engine fuel are described in Specification
D4814.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
This test method is under the jurisdiction of ASTM Committee D02 on the ASTM website.
Petroleum Products, Liquid Fuels, and Lubricants and is the direct responsibility of Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
Subcommittee D02.A0.01 on Gasoline and Gasoline-Oxygenate Blends. 4th Floor, New York, NY 10036, http://www.ansi.org.
Current edition approved Oct. 1, 2014. Published November 2014. Originally Available from California Air Resources Board, P.O. Box 2815, Sacramento,
approved in 1999. Last previous edition approved in 2009 as D6421–99a (2009). CA95815. (Incorporated by reference in California Code of Regulations, Title 13,
DOI: 10.1520/D6421-99AR14. Section 2257.)
2 6
“AProgram to Evaluate a Bench Scale Test Method to Determine the Deposit AvailablefromU.S.GovernmentPrintingOfficeSuperintendentofDocuments,
Forming Tendencies of Port Fuel Injectors,” available from Coordinating Research 732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401, http://
Council, Inc., 219 Perimeter Ctr. Pkwy., Atlanta, GA 30346. www.access.gpo.gov.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6421 − 99a (2014)
3.1.3 deposit control additive, n—materialaddedtothebase can affect emissions and driveability. When heavy enough,
fuel to prevent or remove deposits in the entire engine intake these deposits can lead to driveability symptoms, such as
system. hesitation, hard starting, or loss of power, or a combination
3.1.3.1 Discussion—For the purposes of this test method, thereof, that are easily noticed by the average driver and that
the performance of a deposit control additive is limited to the lead to customer complaints. The mechanism of the formation
electronic PFI tip areas. of deposits is not completely understood. It is believed to be
influenced by many factors, including driving cycle, engine
3.1.4 driveability, n—the quality of a vehicle’s performance
andinjectordesign,andcompositionofthefuel.Theprocedure
characteristics as perceived by the operator in response to
in this test method has been found to build deposits in PFIs on
changes in throttle position.
a consistent basis. This procedure can be used to evaluate
3.1.5 electronic port fuel injector (PFI), n—an electrome-
differences in base fuels and fuel additives. A study of PFI
chanical device used to control fuel flow in an internal
fouling was conducted in both the bench test and the vehicle
combustion engine.
test procedures to obtain a correlation. The vehicle tests were
3.1.6 fouling, v—formation of carbonaceous deposits on the
conducted as described in Test Method D5598. The tests were
pintleormeteringsurfacesofanelectronicfuelinjector,which
conducted on several base gasolines, with and without addi-
reduces fuel flow rate.
tives blended into these base fuels. The PFI bench test proved
3.1.7 pintle, n—a needle-like metering device extending to be reliable, repeatable, and a good predictor of PFI fouling
in test vehicles.
beyond the electronic fuel injector body that is part of an
electronic fuel injector, which controls flow rate and spray 5.1.1 State and Federal Legislative and Regulatory
Action—Legislative and regulatory activity, primarily by the
pattern.
state of California (see 2.3) and the federal government (see
3.1.8 test fuel, n—base fuel, with or without the addition of
2.4), necessitate the acceptance of a standard test method to
a deposit control additive, that is used for evaluation as
evaluate the PFI deposit-forming tendency of an automotive
described in this test method.
spark-ignition engine fuel.
4. Summary of Test Method 5.1.2 Relevance of Results—The operating conditions and
designofthelaboratoryapparatususedinthistestmethodmay
4.1 This test method describes a procedure for evaluating
not be representative of a current vehicle fuel system. These
the formation of deposits in PFIs. The test method includes a
factors must be considered when interpreting results.
bench test procedure that has been shown to rapidly form
deposits in fuel injectors and a procedure for determining 5.2 Test Validity:
resultant flow loss. 5.2.1 Procedural Compliance—The test results are not con-
sideredvalidunlessthetestiscompletedincompliancewithall
4.2 Thistestmethodusesasimulatedfuelsystemconsisting
requirements of this test method. Deviations from the param-
of a fuel pump, filter, pressure regulator, fuel rail, and fuel
eterlimitspresentedinSection10willresultinaninvalidtest.
injectors. A heat source is applied to the fuel injectors to
Engineering judgment shall be applied during conduct of the
simulate the hot-soak portion of the vehicle test (see Test
testmethodwhenassessinganyanomaliestoensurevalidityof
Method D5598).
the test results.
4.3 Each test begins with screened injectors that are known
to foul.The tips of these four clean fuel injectors are placed in 6. Apparatus
an aluminum block.Astainless-steel internal reservoir is filled 7,8
6.1 Automatic Electronic PFI Bench Test Apparatus —
with 2 L of the test fuel.
This apparatus is composed of two units, a fuel handling unit
4.4 During one 60-min test cycle, the fuel injectors are and a controller.
pulsed for 15 s, followed by a 50-min hot-soak interval in 6.1.1 Fuel Handling Unit—This unit houses a machined
whichtheinjectoraluminumblocktemperaturecontrollerisset aluminum fuel rail and a heated aluminum block designed to
at a temperature of 160°C (320°F) and the fuel pressure is accommodate four PFIs. Heaters and thermocouples are
regulated to 263 kPa (38 psig), followed by a 10-min cool- mounted in the heated aluminum block. This unit also houses
down period. Flow measurements for each of the injectors are
a 2.25-L stainless steel reservoir, an electric fuel pump, a fuel
takenatthebeginningofthetest,after22cycles,andattheend regulator, and a variety of valves used to transfer fuel to and
of the test at 44 cycles.
from the reservoir and to deliver fuel under pressure to the
injectors (see Annex A1).
4.5 Thechangeintherateofflowforeachinjectorfromthe
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.
controlandmeasurethetemperatureoftheheatedblock,pulse
5. Significance and Use
5.1 Driveability problems in PFI automobiles were first
The following instrument has been found suitable by interlaboratory coopera-
tive testing: Port Fuel Injector Bench Test Apparatus. Available from Southwest
reported in 1984. Deposits are prone to form on the metering
Research Institute, San Antonio, TX.
surfaces of pintle-type electronic fuel injectors.These deposits
If you are aware of alternative suppliers, please provide this information to
reduce fuel flow through the metering orifices. Reductions in
ASTM International Headquarters. Your comments will receive careful consider-
metered fuel flow result in an upset in the air-fuel ratio, which ation at a meeting of the responsible technical committee, which you may attend.
D6421 − 99a (2014)
the injectors, control the soak period, count the number of test 7. Reagents and Materials
cycles, and control the flow period for the measuring of the
7.1 Purity of Reagents—Reagent grade chemicals shall be
flow rate. The unit is programmed to shut down automatically
used for all test procedures. Unless otherwise noted, it is
at the end of each 22-cycle period.
intended that all reagents conform to the specifications of the
6.1.3 External Pressure Regulator —This regulator is used
Committee onAnalytical Reagents of theAmerican Chemical
to adjust the pressure of the nitrogen gas on the fuel system.
Society,wheresuchspecificationsareavailable. Othergrades
This ensures that the pressure of the fuel in the fuel rail is
may be used provided it is first ascertained that the reagent is
maintainedwithanaccuracyof 66.8kPa(61.0psi)duringthe
of sufficient purity to permit its use without lessening the
test.
accuracy of the determinations.
6.1.4 Electronic PFIs—Only Bosch EV1.1A (Part Number
8,
8,9 7.2 Berryman Chem-Dip Carburetor and Parts Cleaner
0280150360) pintle-style injectors shall be used. The corre-
—This cleaner has been found effective in removing the
spondingChryslerCorp.partnumberis4306024andisclearly
deposits built up in the injectors. This cleaner or any other
marked on the injector. The protective cap shall be removed
carburetor or engine parts cleaner that is proven effective in
from the injector by cutting the plastic cap with a razor blade
removing such deposits shall be used to clean the injectors.
and gently heating with a heat gun. The rubber o-rings and
(Warning—Berryman Chem-Dip contains methylene
spacers shall be removed to expose the bare metal injector tip.
chloride, monochlorotoluene, xylene, ethyl phenols, and xyle-
Each injector shall be screened for fouling capability prior to
nolsthatareextremelydangerousifinhaled,areskinirritanton
use in the procedure. The screening procedure is found in
contact, and are carcinogenic.)
Annex A2.
7.3 Rinsing Solvent—A1:1mixtureofisooctaneandxylene,
6.2 Testing Area—The ambient atmosphere of the testing
orsuitablemixtureofsolvents,shallbeusedtorinsethebench
areashallbereasonablyfreeofcontaminants.Thetemperature
test apparatus reservoir, injectors, and fuel lines between tests.
should be maintained at 24 6 5°C (75 6 9°F). Uniform
Approximately 1 L is used.
temperature is necessary to ensure repeatable injector flow
7.4 Test Fuel—A test fuel is either a base fuel or a
measurements. The specific humidity shall be maintained at a
homogeneous blend of additives and base fuel.Asingle batch
uniform comfortable level. (Warning —Provide adequate
shallbeblendedbeforethestartofthetest.Approximately8L
ventilation and fire protection in areas where flammable or
(2 gal) of fuel is needed for a single test.
volatile liquids and solvents, or both, are used. Suitable
protective clothing is recommended.)
7.5 Additive/Base Fuel—Some test requestors may require
thatthetestfuelbeblendedatthetestlaboratoryand,therefore,
6.3 Laboratory Equipment:
willsupplythedepositcontroladditiveandmay,attheiroption
6.3.1 Analytical Balance—An analytical balance capable of
or if a suitable base fuel is not available at the test laboratory,
0.01 g resolution with a maximum capacity of at least 200 g is
supply untreated base fuel. The test requestor shall supply the
recommended. The balance should be calibrated following the
deposit control additive and, if supplied, the base fuel in
manufacturer’s procedure and frequency recommendations.
appropriatevolumesandpackagingtoensuresafeandefficient
6.3.2 Graduated Cylinders—Fourgraduatedcylindersof50
handling. Blending instructions detailing the concentration
or 100-mL capacity, accurate to the nearest millilitre are
ratio either volumetric-based or mass-based shall accompany
recommended for use in flow testing.
all deposit control additives. Mass-based measurement is
6.3.3 Low Voltage Power Supply—A 12 V, variable, direct
preferred. The blended fuel shall be clearly identified.
current power source should be used in cleaning of the
7.5.1 Additive/Base Fuel Shipment and Storage—The addi-
injectors.
tive shall be shipped in a container as dictated by safety and
6.3.4 Ultrasonic Bath—An ultrasonic bath with heating
environmental r
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D6421 − 99a (Reapproved 2009) D6421 − 99a (Reapproved 2014)
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 D6421; 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 (´) indicates an editorial change since the last revision or reapproval.
1. 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 D6421, contact ASTM International Headquarters. Other properties of significance
to spark-ignition engine fuel are described in Specification D4814.
2. Referenced Documents
2.1 ASTM Standards:
D4814 Specification for Automotive Spark-Ignition Engine Fuel
D5598 Test Method for Evaluating Unleaded Automotive Spark-Ignition Engine Fuel for Electronic Port Fuel Injector Fouling
2.2 ANSI Standard:
MC 96.1 American National Standard for Temperature Measurement Thermocouples
2.3 CARB Standard:
Test Method for Evaluating Port Fuel Injector (PFI) Deposits in Vehicle Engines
2.4 Clean Air Act Amendment:
Clean Air Act Amendments of 1990, Public Law 101–549, Title 1 – Provisions for Attainment and Maintenance of National Air
Quality Standards
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
This test method is under the jurisdiction of ASTM Committee D02 on Petroleum Products Products, Liquid Fuels, and Lubricants and is the direct responsibility of
Subcommittee D02.A0.01 on Gasoline and Gasoline-Oxygenate Blends.
Current edition approved June 1, 2009Oct. 1, 2014. Published November 2009November 2014. Originally approved in 1999. Last previous edition approved in 20042009
as D6421–99a (2004).(2009). DOI: 10.1520/D6421-99AR09.10.1520/D6421-99AR14.
“A Program to Evaluate a Bench Scale Test Method to Determine the Deposit Forming Tendencies of Port Fuel Injectors,” available from Coordinating Research Council,
Inc., 219 Perimeter Ctr. Pkwy., Atlanta, GA 30346.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
Available from California Air Resources Board, P.O. Box 2815, Sacramento, CA 95815. (Incorporated by reference in California Code of Regulations, Title 13, Section
2257.)
Available from U.S. Government Printing Office Superintendent of Documents, 732 N. Capitol St., NW, Mail Stop: SDE, Washington, DC 20401, http://
www.access.gpo.gov.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6421 − 99a (2014)
3.1.1 base fuel, n—unleaded automotive spark-ignition engine fuel that does not contain a deposit control additive but may
contain antioxidants, corrosion inhibitors, metal deactivators, dyes, or oxygenates, or a combination thereof.
3.1.2 cycle, n—a 15-s pulsing period, followed by a 50-min heating period at 160°C (320°F), followed by a 10-min cool-down
period.
3.1.3 deposit control additive, n—material added to the base fuel to prevent or remove deposits in the entire engine intake
system.
3.1.3.1 Discussion—
For the purposes of this test method, the performance of a deposit control additive is limited to the electronic PFI tip areas.
3.1.4 driveability, n—the quality of a vehicle’s performance characteristics as perceived by the operator in response to changes
in throttle position.
3.1.5 electronic port fuel injector (PFI), n—an electromechanical device used to control fuel flow in an internal combustion
engine.
3.1.6 fouling, v—formation of carbonaceous deposits on the pintle or metering surfaces of an electronic fuel injector, which
reduces fuel flow rate.
3.1.7 pintle, n—a needle-like metering device extending beyond the electronic fuel injector body that is part of an electronic fuel
injector, which controls flow rate and spray pattern.
3.1.8 test fuel, n—base fuel, with or without the addition of a deposit control additive, that is used for evaluation as described
in this test method.
4. Summary of Test Method
4.1 This test method describes a procedure for evaluating the formation of deposits in PFIs. The test method includes a bench
test procedure that has been shown to rapidly form deposits in fuel injectors and a procedure for determining resultant flow loss.
4.2 This test method uses a simulated fuel system consisting of a fuel pump, filter, pressure regulator, fuel rail, and fuel injectors.
A heat source is applied to the fuel injectors to simulate the hot-soak portion of the vehicle test (see Test Method D5598).
4.3 Each test begins with screened injectors that are known to foul. The tips of these four clean fuel injectors are placed in an
aluminum block. A stainless-steel internal reservoir is filled with 2 L of the test fuel.
4.4 During one 60-min test cycle, the fuel injectors are pulsed for 15 s, followed by a 50-min hot-soak interval in which the
injector aluminum block temperature controller is set at a temperature of 160°C (320°F) and the fuel pressure is regulated to 263
kPa (38 psig), followed by a 10-min cool-down period. Flow measurements for each of the injectors are taken at the beginning
of the test, after 22 cycles, and at the end of the test at 44 cycles.
4.5 The change in the rate of flow for each injector from the start to the end of the test is used to determine the fouling
percentage of each injector.
5. Significance and Use
5.1 Driveability problems in PFI automobiles were first reported in 1984. Deposits are prone to form on the metering surfaces
of pintle-type electronic fuel injectors. These deposits reduce fuel flow through the metering orifices. Reductions in metered fuel
flow result in an upset in the air-fuel ratio, which can affect emissions and driveability. When heavy enough, these deposits can
lead to driveability symptoms, such as hesitation, hard starting, or loss of power, or a combination thereof, that are easily noticed
by the average driver and that lead to customer complaints. The mechanism of the formation of deposits is not completely
understood. It is believed to be 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 a consistent basis. This procedure can
be used to evaluate differences in base fuels and fuel additives. A study of PFI fouling was conducted in both the bench test and
the vehicle test procedures to obtain a correlation. The vehicle tests were conducted as described in Test Method D5598. The tests
were conducted on several base gasolines, with and without additives blended into these base fuels. The PFI bench test proved to
be reliable, repeatable, and a good predictor of PFI fouling in test vehicles.
5.1.1 State and Federal Legislative and Regulatory Action—Legislative and regulatory activity, primarily by the state of
California (see 2.3) and the federal government (see 2.4), necessitate the acceptance of a standard test method to evaluate the PFI
deposit-forming tendency of an automotive spark-ignition engine fuel.
5.1.2 Relevance of Results—The operating conditions and design of the laboratory apparatus used in this test method may not
be representative of a current vehicle fuel system. These factors must be considered when interpreting results.
5.2 Test Validity:
D6421 − 99a (2014)
5.2.1 Procedural Compliance—The test results are not considered valid unless the test is completed in compliance with all
requirements of this test method. Deviations from the parameter limits presented in Section 10 will result in an invalid test.
Engineering judgment shall be applied during conduct of the test method when assessing any anomalies to ensure validity of the
test results.
6. Apparatus
7,8
6.1 Automatic Electronic PFI Bench Test Apparatus —This apparatus is composed of two units, a fuel handling unit and a
controller.
6.1.1 Fuel Handling Unit—This unit houses a machined aluminum fuel rail and a heated aluminum block designed to
accommodate four PFIs. Heaters and thermocouples are mounted in the heated aluminum block. This unit also houses a 2.25-L
stainless steel reservoir, an electric fuel pump, a fuel regulator, and a variety of valves used to transfer fuel to and from the reservoir
and to deliver fuel under pressure to the injectors (see Annex A1).
6.1.2 Programmable Microprocessor Controller or Other Controller—The controller is used to fill the fuel reservoir, control
and measure the temperature of the heated block, pulse the injectors, control the soak period, count the number of test cycles, and
control the flow period for the measuring of the flow rate. The unit is programmed to shut down automatically at the end of each
22-cycle period.
6.1.3 External Pressure Regulator —This regulator is used to adjust the pressure of the nitrogen gas on the fuel system. This
ensures that the pressure of the fuel in the fuel rail is maintained with an accuracy of 66.8 kPa (61.0 psi) during the test.
8,9
6.1.4 Electronic PFIs—Only Bosch EV1.1A (Part Number 0280150360) pintle-style injectors shall be used. The correspond-
ing Chrysler Corp. part number is 4306024 and is clearly marked on the injector. The protective cap shall be removed from the
injector by cutting the plastic cap with a razor blade and gently heating with a heat gun. The rubber o-rings and spacers shall be
removed to expose the bare metal injector tip. Each injector shall be screened for fouling capability prior to use in the procedure.
The screening procedure is found in Annex A2.
6.2 Testing Area—The ambient atmosphere of the testing area shall be reasonably free of contaminants. The temperature should
be maintained at 24 6 5°C (75 6 9°F). Uniform temperature is necessary to ensure repeatable injector flow measurements. The
specific humidity shall be maintained at a uniform comfortable level. (Warning —Provide adequate ventilation and fire protection
in areas where flammable or volatile liquids and solvents, or both, are used. Suitable protective clothing is recommended.)
6.3 Laboratory Equipment:
6.3.1 Analytical Balance—An analytical balance capable of 0.01 g resolution with a maximum capacity of at least 200 g is
recommended. The balance should be calibrated following the manufacturer’s procedure and frequency recommendations.
6.3.2 Graduated Cylinders—Four graduated cylinders of 50 or 100-mL capacity, accurate to the nearest millilitre are
recommended for use in flow testing.
6.3.3 Low Voltage Power Supply—A 12 V, variable, direct current power source should be used in cleaning of the injectors.
6.3.4 Ultrasonic Bath—An ultrasonic bath with heating capabilities should be used for the cleaning of the injectors.
6.3.5 Pipette Bulb—A pipette bulb should be used to draw injector cleaning solution into the injector for cleaning.
6.3.6 Pipette—A disposable transfer pipette should be used to fill injectors with the cleaning solution during the cleaning
procedure.
6.3.7 Plastic Disposable Beakers—Disposable plastic beakers of approximately 150 mL or other containers of equivalent size
should be used to contain the injector cleaning fluid during the clean up of the injectors.
6.4 Data Acquisition—A data acquisition device, capable of collecting the raw data in accordance with 10.4, shall be required.
7. Reagents and Materials
7.1 Purity of Reagents—Reagent grade chemicals shall be used for all test procedures. Unless otherwise noted, it is intended
that all reagents conform to the specifications of the Committee on Analytical Reagents of the American Chemical Society, where
such specifications are available. Other grades may be used provided it is first ascertained that the reagent is of sufficient purity
to permit its use without lessening the accuracy of the determinations.
8,11
7.2 Berryman Chem-Dip Carburetor and Parts Cleaner —This cleaner has been found effective in removing the deposits
built up in the injectors. This cleaner or any other carburetor or engine parts cleaner that is proven effective in removing such
The following instrument has been found suitable by interlaboratory cooperative testing: Port Fuel Injector Bench Test Apparatus. Available from Southwest Research
Institute, San Antonio, TX.
If you are aware of alternative suppliers, please provide this information to ASTM International Headquarters. Your comments will receive careful consideration at a
meeting of the responsible technical committee, which you may attend.
The sole source of supply of the pintle-style injectors known to the committee at this time is Robert Bosch Corp., 25th Ave., Broadview, IL 60153.
Reagent Chemicals, American Chemical Society Specifications, American Chemical Society, Washingto
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