ASTM D6421 Test Method for Evaluating Automotive Spark-Ignition Engine Fuel
ASTM D6421 Standard Test Method for Evaluating Automotive Spark-Ignition Engine Fuel for Electronic Port Fuel Injector Fouling by Bench Procedure
6. Apparatus
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 +/- 6.8 kPa (+/- 1.0 psi) during the test.
6.1.4 Electronic PFIs - Only Bosch EV1.1A (Part Number 0280150360) pintle-style injectors shall be used. The corresponding 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 +/-5°C (75 +/-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.
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 deposits shall be used to clean the injectors. (Warning - Berryman Chem-Dip contains methylene chloride, monochlorotoluene, xylene, ethyl phenols, and xylenols that are extremely dangerous if inhaled, are skin irritant on contact, and are carcinogenic.)
7.3 Rinsing Solvent - A 1:1 mixture of isooctane and xylene, or suitable mixture of solvents, shall be used to rinse the bench test apparatus reservoir, injectors, and fuel lines between tests. Approximately 1 L is used.
7.4 Test Fuel - A test fuel is either a base fuel or a homogeneous blend of additives and base fuel. A single batch shall be blended before the start of the test. Approximately 8 L (2 gal) of fuel is needed for a single test.
7.5 Additive/Base Fuel - Some test requestors may require that the test fuel be blended at the test laboratory and, therefore, will supply the deposit control additive and may, at their option or if a suitable base fuel is not available at the test laboratory, supply untreated base fuel. The test requestor shall supply the deposit control additive and, if supplied, the base fuel in appropriate volumes and packaging to ensure safe and efficient handling. Blending instructions detailing the concentration ratio either volumetric-based or mass-based shall accompany all deposit control additives. Mass-based measurement is preferred. The blended fuel shall be clearly identified.
7.5.1 Additive/Base Fuel Shipment and Storage - The additive shall be shipped in a container as dictated by safety and environmental regulations. The additive shall be stored in accordance with all applicable safety and environmental regulations.
7.5.2 Base Fuel - The base fuel used for this test method should be typical of commercial, automotive spark-ignition engine fuel. The base fuel may contain oxygenates typical of those being used commercially.
7.6 Nitrogen Gas (not less than 99.9 % Pure) - This gas shall be used to pressurize the fuel system and the fuel rail.
