# 40 CFR 89.424 - Dilute emission sampling calculations.

(a) The final reported emission test results are computed by use of the following formula:

(b) The mass of each pollutant for each mode for bag measurements and diesel heat exchanger system measurements is determined from the following equations:

(1) Hydrocarbon mass:

(2) Oxides of nitrogen mass:

(3) Carbon monoxide mass:

(4) Carbon dioxide mass:

(c) The mass of each pollutant for the mode for flow compensated sample systems is determined from the following equations:

(d) Meaning of symbols:

(1) For hydrocarbon equations:

(2) For oxides of nitrogen equations:

(3) For carbon monoxide equations:

The following calculation assumes the carbon to hydrogen ratio of the fuel is 1:1.85. As an option the measured actual carbon to hydrogen ratio may be used:

(Note: If a CO instrument that meets the criteria specified in 40 CFR part 1065, subpart C, is used without a sample dryer according to 40 CFR 1065.145, COem must be substituted directly for COe and COdm must be substituted directly for COd.)

(4) For carbon dioxide equation:

(6) Measured “dry” concentrations shall be corrected to a wet basis, if not already measured on a wet basis. This section is applicable only for measurements made on dilute exhaust gas. Correction to a wet basis shall be according to the following formula:

Where: KW is determined according to the equation in paragraph (d)(6)(i) or (d)(6)(ii), of this section.

(i) For wet CO2 measurement:

(ii) For dry CO2 measurement:

(iii) For the equations in paragraph (d)(6)(i) and (d)(6)(ii) of this section, the following equation applies:

Where: Ha and Hd are the grams of water per kilogram of dry air; as illustrated in the following equations:

(e) The final modal reported brake-specific fuel consumption (bsfc) shall be computed by use of the following formula:

(f) The mass of fuel for the mode is determined from mass fuel flow measurements made during the mode, or from the following equation: