40 CFR Part 86, Appendix IX to Part 86 - Experimentally Determining the R-Factor for Bench Aging Durability Procedures

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View PDF at GPO Pt. 86, App. IX
Appendix IX to Part 86—Experimentally Determining the R-Factor for Bench Aging Durability Procedures
The R-Factor is the catalyst thermal reactivity coefficient used in the bench aging time (BAT) equation [Ref. § 86.1826-08(d)(3)]. Manufacturers may determine the value of R experimentally using the following procedures.
1. Using the applicable bench cycle and aging bench hardware, age several catalysts (minimum of 3 of the same catalyst design) at different control temperatures between the normal operating temperature and the damage limit temperature. Measure emissions (or catalyst inefficiency (1-catalyst efficiency)) for each constituent. Assure that the final testing yields data between one- and two-times the standard.
2. Estimate the value of R and calculate the effective reference temperature (Tr) for the bench aging cycle for each control temperature according to the procedure described in § 86.1826-08(d)(4).
3. Plot emissions (or catalyst inefficiency) versus aging time for each catalyst. Calculate the least-squared best-fit line through the data. For the data set to be useful for this purpose the data should have an approximately common intercept between 0 and 4000 miles. See the following graph for an example.
4. Calculate the slope of the best-fit line for each aging temperature.
5. Plot the natural log (ln) of the slope of each best-fit line (determined in step 4) along the vertical axis, versus the inverse of aging temperature (1/(aging temperature, deg K)) along the horizontal axis, Calculate the least-squared best-fit lines through the data. The slope of the line is the R-factor. See the following graph for an example.
6. Compare the R-factor to the initial value that was used in Step 2. If the calculated R-factor differs from the initial value by more than 5%, choose a new R-factor that is between the initial and calculated values, then repeat Steps 2-6 to derive a new R-factor. Repeat this process until the calculated R-factor is within 5% of the initially assumed R-factor.
7. Compare the R-factor determined separately for each constituent. Use the lowest R-factor (worst case) for the BAT equation.
[71 FR 2837, Jan. 17, 2006]

Title 40 published on 2014-07-01

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

  • 2015-02-19; vol. 80 # 33 - Thursday, February 19, 2015
    1. 80 FR 9078 - Amendments Related to: Tier 3 Motor Vehicle Emission and Fuel Standards, Nonroad Engine and Equipment Programs, and MARPOL Annex VI Implementation
      GPO FDSys XML | Text
      ENVIRONMENTAL PROTECTION AGENCY
      Direct final rule.
      This final rule is effective on May 5, 2015, without further notice, unless EPA receives adverse comment by April 6, 2015. If EPA receives adverse comment on any provisions of the rule, we will publish a timely withdrawal in the Federal Register informing the public that those specific provisions will not take effect. The incorporation by reference of certain publications listed in this regulation is approved by the Director of the Federal Register as of May 5, 2015.
      40 CFR Parts 59, 80, 85, 86, 600, 1037, 1043, 1051, 1054, 1060, 1065, and 1066

Title 40 published on 2014-07-01

The following are ALL rules, proposed rules, and notices (chronologically) published in the Federal Register relating to 40 CFR 86 after this date.

  • 2015-02-19; vol. 80 # 33 - Thursday, February 19, 2015
    1. 80 FR 8826 - Amendments Related to: Tier 3 Motor Vehicle Emission and Fuel Standards, Nonroad Engine and Equipment Programs, and MARPOL Annex VI Implementation
      GPO FDSys XML | Text
      ENVIRONMENTAL PROTECTION AGENCY
      Proposed rule.
      Comments: Written comments must be received by April 6, 2015. Public Hearing: If anyone contacts EPA requesting to speak at a public hearing by February 24, 2015, a public hearing will be held in Ann Arbor, Michigan on March 6, 2015. Inquire about arrangements for a public hearing as described in “ FOR FURTHER INFORMATION CONTACT ”.
      40 CFR Parts 59, 80, 85, 86, 600, 1037, 1043, 1051, 1054, 1060, 1065, and 1066