40 CFR 91.426 - Dilute emission sampling calculations.

§ 91.426 Dilute emission sampling calculations.
(a) The final reported emission test results must be computed by use of the following formula:
Where:
Awm=Weighted mass emission level (HC, CO, CO2, or NOX) for a test [g/kW-hr].
Wi=Average mass flow rate of an emission from a test engine during mode i [g/hr].
WFi = Weighting factor for each mode i as defined in § 91.410(a).
Pi = Gross average power generated during mode i [kW] calculated from the following equation (power for the idle mode shall always be zero for this calculation):
speed = average engine speed measured during mode i [rev./minute]
torque = average engine torque measured during mode i [N-m]
KHi = Humidity correction factor for mode i. This correction factor only affects calculations for NOX and is equal to one for all other emissions. KHi is also equal to one for all two-stroke engines.
(b) The mass flow rate (Wi) of an emission for mode i is determined from the following equation:
Where:
Qi = Volumetric flow rate of the dilute exhaust through the CVS at standard conditions [m3/hr at STP].
D = Density of a specific emission (DHC, DCO, DCO2, DNOx) in the exhaust [g/m3].
DFi = Dilution factor of the dilute exhaust during mode i.
CDi = Concentration of the emission (HC, CO, NOX) in the dilute exhaust extracted from the CVS during mode i [ppm].
CBi = Concentration of the emission (HC, CO, NOX) in the background sample during mode i [ppm].
STP = Standard temperature and pressure. All volumetric calculations made for the equations in this section are to be corrected to a standard temperature of 20 °C and 101.3 kPa.
(c) Densities for emissions that are to be measured for this test procedure are:
DHC = 576.8 g/m3
DNOX = 1912 g/m3
DCO = 1164 g/m3
DCO2 = 1829 g/m3
(1) The value of DHC above is calculated based on the assumption that the fuel used has a carbon to hydrogen ratio of 1:1.85. For other fuels, DHC can be calculated from the following formula:
Where:
MHC = Molecular weight of the hydrocarbon molecule divided by the number of carbon atoms in the molecule [g/mole].
RSTP = Ideal gas constant for a gas at STP = 0.024065 [m3-mole].
(2) The idealized molecular weight of the exhaust hydrocarbons, ie., the molecular weight of the hydrocarbon molecule divided by the number of carbon atoms in the molecule, MHC can be calculated from the following formula:
Where:
MC = Molecular weight of carbon = 12.01 [g/mole].
MH = Molecular weight of hydrogen = 1.008 [g/mole].
α = Hydrogen to carbon ratio of the test fuel.
(3) The value of DNOx above assumes that NOX in entirely in the form of NO2.
(d) The dilution factor (DF) is the ratio of the volumetric flow rate of the background air to that of the raw engine exhaust. The following formula is used to determine DF:
Where:
CDHC = Concentration of HC in the dilute sample [ppm].
CDCO = Concentration of CO in the dilute sample [ppm].
CDCO2 = Concentration of CO2 in the dilute sample [ppm].
(e) The humidity correction factor KH is an adjustment made to the measured NOX. This corrects for the sensitivity that a spark-ignition engine has to the humidity of its combustion air. The following formula is used to determine KH for NOX calculations:
Where:
H = Absolute humidity of the engine intake air [grams of water per kilogram of dry air].
(f) The absolute humidity of the engine intake air H is calculated using the following formula:
Where:
Pdew = Saturated vapor pressure at the dew point temperature [kPa].
Pb = Barometric pressure [kPa].
(g) The fuel mass flow rate Fi can be either measured or calculated using the following formula:
Where:
Mf = Mass of fuel consumed by the engine during the mode [g].
T = Duration of the sampling period [hr].
(h) The mass of fuel consumed during the mode sampling period, MFUEL can be calculated from the following equation:
Where:
GS = Mass of carbon measured during the mode sampling period [g].
R2 = The fuel carbon weight fraction, which is the mass of carbon in fuel per mass of fuel [g/g].
(i) The grams of carbon measured during the mode GS can be calculated from the following equation:
Where:
HCmass = mass of hydrocarbon emissions for the mode sampling period [g].
COmass = mass of carbon monoxide emissions for the mode sampling period [g].
CO2mass = mass of carbon dioxide emissions for the mode sampling period [g].
α = The atomic hydrogen to carbon ratio of the fuel.

Title 40 published on 2013-07-01

no entries appear in the Federal Register after this date.

This is a list of United States Code sections, Statutes at Large, Public Laws, and Presidential Documents, which provide rulemaking authority for this CFR Part.

This list is taken from the Parallel Table of Authorities and Rules provided by GPO [Government Printing Office].

It is not guaranteed to be accurate or up-to-date, though we do refresh the database weekly. More limitations on accuracy are described at the GPO site.


United States Code
U.S. Code: Title 42 - THE PUBLIC HEALTH AND WELFARE

§ 7401 - Congressional findings and declaration of purpose

§ 7402 - Cooperative activities

§ 7403 - Research, investigation, training, and other activities

§ 7404 - Research relating to fuels and vehicles

§ 7405 - Grants for support of air pollution planning and control programs

§ 7406 - Interstate air quality agencies; program cost limitations

§ 7407 - Air quality control regions

§ 7408 - Air quality criteria and control techniques

§ 7409 - National primary and secondary ambient air quality standards

§ 7410 - State implementation plans for national primary and secondary ambient air quality standards

§ 7411 - Standards of performance for new stationary sources

§ 7412 - Hazardous air pollutants

§ 7413 - Federal enforcement

§ 7414 - Recordkeeping, inspections, monitoring, and entry

§ 7415 - International air pollution

§ 7416 - Retention of State authority

§ 7417 - Advisory committees

§ 7418 - Control of pollution from Federal facilities

§ 7419 - Primary nonferrous smelter orders

§ 7420 - Noncompliance penalty

§ 7421 - Consultation

§ 7422 - Listing of certain unregulated pollutants

§ 7423 - Stack heights

§ 7424 - Assurance of adequacy of State plans

§ 7425 - Measures to prevent economic disruption or unemployment

§ 7426 - Interstate pollution abatement

§ 7427 - Public notification

§ 7428 - State boards

§ 7429 - Solid waste combustion

§ 7430 - Emission factors

§ 7431 - Land use authority

§ 7450 to 7459 - Repealed.

§ 7470 - Congressional declaration of purpose

§ 7471 - Plan requirements

§ 7472 - Initial classifications

§ 7473 - Increments and ceilings

§ 7474 - Area redesignation

§ 7475 - Preconstruction requirements

§ 7476 - Other pollutants

§ 7477 - Enforcement

§ 7478 - Period before plan approval

§ 7479 - Definitions

§ 7491 - Visibility protection for Federal class I areas

§ 7492 - Visibility

§ 7501 - Definitions

§ 7502 - Nonattainment plan provisions in general

§ 7503 - Permit requirements

§ 7504 - Planning procedures

§ 7505 - Environmental Protection Agency grants

§ 7505a - Maintenance plans

§ 7506 - Limitations on certain Federal assistance

§ 7506a - Interstate transport commissions

§ 7507 - New motor vehicle emission standards in nonattainment areas

§ 7508 - Guidance documents

§ 7509 - Sanctions and consequences of failure to attain

§ 7509a - International border areas

§ 7511 - Classifications and attainment dates

§ 7511a - Plan submissions and requirements

§ 7511b - Federal ozone measures

§ 7511c - Control of interstate ozone air pollution

§ 7511d - Enforcement for Severe and Extreme ozone nonattainment areas for failure to attain

§ 7511e - Transitional areas

§ 7511f - NO

§ 7512 - Classification and attainment dates

§ 7512a - Plan submissions and requirements

§ 7513 - Classifications and attainment dates

§ 7513a - Plan provisions and schedules for plan submissions

§ 7513b - Issuance of RACM and BACM guidance

§ 7514 - Plan submission deadlines

§ 7514a - Attainment dates

§ 7515 - General savings clause

§ 7521 - Emission standards for new motor vehicles or new motor vehicle engines

§ 7522 - Prohibited acts

§ 7523 - Actions to restrain violations

§ 7524 - Civil penalties

§ 7525 - Motor vehicle and motor vehicle engine compliance testing and certification

§ 7541 - Compliance by vehicles and engines in actual use

§ 7542 - Information collection

§ 7543 - State standards

§ 7544 - State grants

§ 7545 - Regulation of fuels

§ 7546 - Renewable fuel

§ 7547 - Nonroad engines and vehicles

§ 7548 - Study of particulate emissions from motor vehicles

§ 7549 - High altitude performance adjustments

§ 7550 - Definitions

§ 7551 - Omitted

§ 7552 - Motor vehicle compliance program fees

§ 7553 - Prohibition on production of engines requiring leaded gasoline

§ 7554 - Urban bus standards

§ 7571 - Establishment of standards

§ 7572 - Enforcement of standards

§ 7573 - State standards and controls

§ 7574 - Definitions

§ 7581 - Definitions

§ 7582 - Requirements applicable to clean-fuel vehicles

§ 7583 - Standards for light-duty clean-fuel vehicles

§ 7584 - Administration and enforcement as per California standards

§ 7585 - Standards for heavy-duty clean-fuel vehicles (GVWR above 8,500 up to 26,000 lbs.)

§ 7586 - Centrally fueled fleets

§ 7587 - Vehicle conversions

§ 7588 - Federal agency fleets

§ 7589 - California pilot test program

§ 7590 - General provisions

§ 7601 - Administration

§ 7602 - Definitions

§ 7603 - Emergency powers

§ 7604 - Citizen suits

§ 7605 - Representation in litigation

§ 7606 - Federal procurement

§ 7607 - Administrative proceedings and judicial review

§ 7608 - Mandatory licensing

§ 7609 - Policy review

§ 7610 - Other authority

§ 7611 - Records and audit

§ 7612 - Economic impact analyses

§ 7613 - Repealed.

§ 7614 - Labor standards

§ 7615 - Separability

§ 7616 - Sewage treatment grants

§ 7617 - Economic impact assessment

§ 7618 - Repealed.

§ 7619 - Air quality monitoring

§ 7620 - Standardized air quality modeling

§ 7621 - Employment effects

§ 7622 - Employee protection

§ 7623 - Repealed.

§ 7624 - Cost of vapor recovery equipment

§ 7625 - Vapor recovery for small business marketers of petroleum products

42 U.S. Code § 7450 to 7459 - Repealed.

§ 7625a - Statutory construction

§ 7626 - Authorization of appropriations

§ 7627 - Air pollution from Outer Continental Shelf activities

§ 7628 - Demonstration grant program for local governments

§ 7641 - Noise abatement

§ 7642 - Authorization of appropriations

§ 7651 - Findings and purposes

§ 7651a - Definitions

§ 7651b - Sulfur dioxide allowance program for existing and new units

§ 7651c - Phase I sulfur dioxide requirements

§ 7651d - Phase II sulfur dioxide requirements

§ 7651e - Allowances for States with emissions rates at or below 0.80 lbs/mmBtu

§ 7651f - Nitrogen oxides emission reduction program

§ 7651g - Permits and compliance plans

§ 7651h - Repowered sources

§ 7651i - Election for additional sources

§ 7651j - Excess emissions penalty

§ 7651k - Monitoring, reporting, and recordkeeping requirements

42 U.S. Code § -

§ 7651m - Enforcement

§ 7651n - Clean coal technology regulatory incentives

42 U.S. Code § -

§ 7661 - Definitions

§ 7661a - Permit programs

§ 7661b - Permit applications

§ 7661c - Permit requirements and conditions

§ 7661d - Notification to Administrator and contiguous States

§ 7661e - Other authorities

§ 7661f - Small business stationary source technical and environmental compliance assistance program

§ 7671 - Definitions

§ 7671a - Listing of class I and class II substances

§ 7671b - Monitoring and reporting requirements

§ 7671c - Phase-out of production and consumption of class I substances

§ 7671d - Phase-out of production and consumption of class II substances

§ 7671e - Accelerated schedule

§ 7671f - Exchange authority

§ 7671g - National recycling and emission reduction program

§ 7671h - Servicing of motor vehicle air conditioners

§ 7671i - Nonessential products containing chlorofluorocarbons

§ 7671j - Labeling

§ 7671k - Safe alternatives policy

42 U.S. Code § -

§ 7671m - Relationship to other laws

§ 7671n - Authority of Administrator

42 U.S. Code § -

§ 7671p - International cooperation

§ 7671q - Miscellaneous provisions