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CFR › Title 40 › Chapter I › Subchapter U › Part 1065 › Subpart G › Section 1065.670

40 CFR 1065.670 - NO X intake-air humidity and temperature corrections.

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§ 1065.670 NOX intake-air humidity and temperature corrections.
See the standard-setting part to determine if you may correct NOX emissions for the effects of intake-air humidity or temperature. Use the NOX intake-air humidity and temperature corrections specified in the standard-setting part instead of the NOX intake-air humidity correction specified in this part 1065. If the standard-setting part does not prohibit correcting NOX emissions for intake-air humidity according to this part 1065, correct NOX concentrations for intake-air humidity as described in this section. See § 1065.650(c)(1) for the proper sequence for applying the NOX intake-air humidity and temperature corrections. You may use a time-weighted mean combustion air humidity to calculate this correction if your combustion air humidity remains within a tolerance of ±0.0025 mol/mol of the mean value over the test interval. For intake-air humidity correction, use one of the following approaches:
See the standard-setting part to determine if you may correct NOX emissions for the effects of intake-air humidity or temperature. Use the NOX intake-air humidity and temperature corrections specified in the standard-setting part instead of the NOX intake-air humidity correction specified in this part 1065. If the standard-setting part does not prohibit correcting NOX emissions for intake-air humidity according to this part 1065, first apply any NOX corrections for background emissions and water removal from the exhaust sample, then correct NOX concentrations for intake-air humidity. You may use a time-weighted mean combustion air humidity to calculate this correction if your combustion air humidity remains within a tolerance of ±0.0025 mol/mol of the mean value over the test interval. For intake-air humidity correction, use one of the following approaches:
(a) For compression-ignition engines, correct for intake-air humidity using the following equation:
Example:
x NOxuncor = 700.5 µmol/mol
x H2O = 0.022 mol/mol
x NOxcor = 700.5 · (9.953 · 0.022 0.832)
x NOxcor = 736.2 µmol/mol
(b) For spark-ignition engines, correct for intake-air humidity using the following equation:
Example:
x NOxuncor = 154.7 µmol/mol
x H2O = 0.022 mol/mol
x NOxcor = 154.7 · (18.840 · 0.022 0.68094)
x NOxcor = 169.5 µmol/mol
(c) Develop your own correction, based on good engineering judgment.
[75 FR 23056, Apr. 30, 2010, as amended at 76 FR 57466, Sept. 15, 2011]

Title 40 published on 2012-07-01

The following are only the Rules published in the Federal Register after the published date of Title 40.

For a complete list of all Rules, Proposed Rules, and Notices view the Rulemaking tab.

  • 2012-08-27; vol. 77 # 166 - Monday, August 27, 2012
    1. 77 FR 51701 - EPA's Denial of the Petition To Reconsider the Greenhouse Gas Emissions Standards and Fuel Efficiency Standards for Medium- and Heavy-Duty Engines and Vehicles
      GPO FDSys XML | Text
      ENVIRONMENTAL PROTECTION AGENCY
      Denial of petition to reconsider.
      This denial is effective August 27, 2012.
      40 CFR Parts 85, 86, 600, 1033, 1036, 1037, 1039, 1065, 1066, and 1068

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Title 40 published on 2012-07-01

The following are ALL rules, proposed rules, and notices (chronologically) published in the Federal Register relating to 40 CFR 1065 after this date.

  • 2012-08-27; vol. 77 # 166 - Monday, August 27, 2012
    1. 77 FR 51701 - EPA's Denial of the Petition To Reconsider the Greenhouse Gas Emissions Standards and Fuel Efficiency Standards for Medium- and Heavy-Duty Engines and Vehicles
      GPO FDSys XML | Text
      ENVIRONMENTAL PROTECTION AGENCY
      Denial of petition to reconsider.
      This denial is effective August 27, 2012.
      40 CFR Parts 85, 86, 600, 1033, 1036, 1037, 1039, 1065, 1066, and 1068