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
11. Report
11.1 Report the Following Information:
11.1.1 Dates of testing.
11.1.2 Fuel identification.
11.1.3 Temperature of heat soak.
11.1.4 Flow length.
11.1.5 Pulsing length.
11.1.6 Cool period time.
11.1.7 Fuel rail pressure.
11.1.8 Temperature at time of flow readings.
11.1.9 Mass flow readings (3) for each injector at the beginning of the test (initial), at 22 cycles and 44 cycles.
11.1.10 Average flow readings for each injector at 22 cycles and 44 cycles.
11.1.11 Percent flow loss (3) for each injector at 22 cycles and 44 cycles.
11.1.12 Average percent flow loss for each injector at 22 cycles and 44 cycles.
11.1.13 Average percent flow loss for the four injectors at 22 cycles and 44 cycles.
11.2 Data Acquisition Summary Report - The test validation criteria report, derived from the data acquisition equipment, shall include a graphical representation of the fuel rail pressure, a graphical representation of the manifold temperature, and a graphical representation of the timing of the test cycles.
12. Precision and Bias
12.1 The precision of this test method was determined based on a 1995 interlaboratory round-robin test program. A total of six labs participated, and each lab analyzed samples of eight fuels. All labs analyzed duplicate samples, and some examined triplicate samples of each fuel. Statistical examination yielded the interlaboratory test results for repeatability and reproducibility given in Fig. 1. These were obtained using the precision statistics given in Table X1.1 (see Appendix X1), which include the number of runs, the average percent fouling, the repeatability value, and the reproducibility value.
12.2 Repeatability - The difference between successive test results obtained by the same operator with the same apparatus under constant operating conditions on identical test material would, in the long run, in the normal and correct application of the test method, exceed the values below in only one case in twenty.
r = 8.65 + 0.43 x (average percent fouling)
12.3 Reproducibility - The difference between two single and independent test results obtained by different operators working in different laboratories on identical test material would, in the long run, in the normal and correct operation of the test method, exceed the values below in only one case in twenty.
R = 12.75 + 1.34 x (average percent fouling)
12.4 Bias - Since there is no accepted reference fuel suitable for determining the bias for the procedures used in this test method, bias has not been determined.
13. Keywords
13.1 base fuel; bench test; deposit control additive; deposits (in internal combustion engines); electronic port fuel injector (PFI); flow rate, hot soak; injector fouling; pintle; spark-ignition engine fuel; test fuel
