(a) Correct the emissions in a gaseous sample for background using the following equation:[GRAPHIC] [TIFF OMITTED] TR28AP14.099 Where:x[emission]dexh = measured emission concentration in dilute
exhaust (after dry-to-wet correction, if applicable).x[emission]bkgnd = measured emission concentration in the
dilution air (after dry-to-wet correction, if applicable).DF = dilution factor, as determined in paragraph (b) of this section. [GRAPHIC] [TIFF OMITTED] TR28AP14.100 Where: xCO2 = amount of CO2 measured in the sample over
the test interval.xNMHC = amount of C1-equivalent NMHC measured in
the sample over the test interval.xCH4 = amount of CH4 measured in the sample over
the test interval.xCO = amount of CO measured in the sample over the test
interval.a = atomic hydrogen-to-carbon ratio of the test fuel. You may measure a
or use default values from Table 1 of 40 CFR 1065.655.b = atomic oxygen-to-carbon ratio of the test fuel. You may measure b or
use default values from Table 1 of 40 CFR 1065.655. [GRAPHIC] [TIFF OMITTED] TR28AP14.101
(c) Determine the dilution factor, DF, over the test interval for partial-flow dilution sample systems using the following equation:[GRAPHIC] [TIFF OMITTED] TR28AP14.152 Where:
Vdexhstd = total dilute exhaust volume sampled over the test interval, corrected to standard reference conditions.
Vexhstd = total exhaust volume sampled from the vehicle, corrected to standard reference conditions.[GRAPHIC] [TIFF OMITTED] TR28AP14.102
(d) Determine the time-weighted dilution factor, DFw, over the duty cycle using the following equation:[GRAPHIC] [TIFF OMITTED] TR28AP14.103 Where: N = number of test intervals.i = test interval numbert = duration of the test interval.DF = dilution factor over the test interval. Example:[GRAPHIC] [TIFF OMITTED] TR28AP14.104