eCFR Reference Browser

---

title: "40 CFR §90.419"

source: "https://www.ecfr.gov/current/title-40/section-90.419"

title_number: "40"

volume_number: "22"

chapter_number: "Unknown"

subchapter_code: "C"

subchapter_subject: "AIR PROGRAMS (CONTINUED)"

part_code: "90"

part_subject: "CONTROL OF EMISSIONS FROM NONROAD SPARK-IGNITION ENGINES AT OR BELOW 19 KILOWATTS"

subpart_code: "E"

subpart_subject: "Gaseous Exhaust Test Procedures"

section_number: "90.419"

section_subject: "Raw emission sampling calculations—gasoline fueled engines."

cfr_reference: "40 CFR 90.419"

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)Derive the final weighted brake-specific mass emission rates (g/kW-hr) through the steps described in this section.

(b)Air and fuel flow method. If both air and fuel flow mass rates are measured, use the following equations to determine the weighted emission values for the test engine:

(c)Fuel flow method. The following equations are to be used when fuel flow is selected as the basis for mass emission calculations using the raw gas method.

KH = Factor for correcting the effects of humidity on NO2 formation for 4-stroke gasoline small engines, as follows:

KH = (9.953 × H + 0.832)

(d)Calculate the final weighted brake-specific emission rate for each individual gas component using the following equation:

§90.419 - Raw emission sampling calculations—gasoline fueled engines.