eCFR Reference Browser

---

title: "40 CFR §89.424"

source: "https://www.ecfr.gov/current/title-40/section-89.424"

title_number: "40"

volume_number: "22"

chapter_number: "Unknown"

subchapter_code: "C"

subchapter_subject: "AIR PROGRAMS (CONTINUED)"

part_code: "89"

part_subject: "CONTROL OF EMISSIONS FROM NEW AND IN-USE NONROAD COMPRESSION-IGNITION ENGINES"

subpart_code: "E"

subpart_subject: "Exhaust Emission Test Procedures"

section_number: "89.424"

section_subject: "Dilute emission sampling calculations."

cfr_reference: "40 CFR 89.424"

title_name: "Title 40"

title_subject: "Protection of Environment"

parts_covered: "Parts 87 to 95"

revised_date: "Revised as of July 1, 2017"

publication_date: "As of July 1, 2017"

contains_description: "Containing a codification of documents of general applicability and future effect"

publication_info: "Published by the Office of the Federal Register National Archives and Records Administration as a Special Edition of the Federal Register"

---

(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:

§89.424 - Dilute emission sampling calculations.