# 40 CFR 86.884-14 - Calculations.

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§ 86.884-14 Calculations.
(a) If the measured half-second opacity values were obtained with a smokemeter with an optical path length different than shown in the table in § 86.884-8(c), then convert the measured half-second values or the original instantaneous values to the appropriate equivalent optical path length values specified in the table. Convert the opacity values according to the following equations:
Lm and Ls must use consistent units in the above equation
Where:
Nm=Measured half-second value for conversion, percent opacity
Lm=Measuring smokemeter optical path length, meters
Ls=Standard optical path length corresponding with engine power, n
Ns=Standard half-second value, percent opacity
(b) Average the 45 readings in § 86.884-13(d)(3) or the equivalent converted values from paragraph (a) of this section if appropriate, and designate the value as “A”. This is the value for the engine acceleration mode.
(c) Average the 15 readings in § 86.884-13(d)(4) or the equivalent converted values from paragraph (a) of this section if appropriate, and designate the value as “B”. This is the value for the engine lugging mode.
(d) Average the 9 readings in § 86.884-13(d)(5) or the equivalent converted values from paragraph (a) of this section if appropriate, and designate the value as “C”. This is the value for the peaks in either mode.
(e)
(1) If multiple smokemeters were used, the half-second values for each mode from each smokemeter shall be combined and the calculated average based upon the total number of combined values.
(2) For example, if two smokemeters were used for acceleration mode data, 45 half-second values in each data set from both smokemeters would be combined to form a data set of 90 values, which would then be averaged.
[62 FR 47123, Sept. 5, 1997, as amended at 69 FR 2441, Jan. 15, 2004]
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§ 86.884-14 Calculations.

(a) If the measured half-second opacity values were obtained with a smokemeter with an optical path length different than shown in the table in § 86.884-8(c), then convert the measured half-second values or the original instantaneous values to the appropriate equivalent optical path length values specified in the table. Convert the opacity values according to the following equations:

Lm and Ls must use consistent units in the above equation
Where:
Nm = Measured half-second value for conversion, percent opacity
Lm = Measuring smokemeter optical path length, meters
Ls = Standard optical path length corresponding with engine power, n
Ns = Standard half-second value, percent opacity

(b) Average the 45 readings in § 86.884-13(d)(3) or the equivalent converted values from paragraph (a) of this section if appropriate, and designate the value as “A”. This is the value for the engine acceleration mode.

(c) Average the 15 readings in § 86.884-13(d)(4) or the equivalent converted values from paragraph (a) of this section if appropriate, and designate the value as “B”. This is the value for the engine lugging mode.

(d) Average the 9 readings in § 86.884-13(d)(5) or the equivalent converted values from paragraph (a) of this section if appropriate, and designate the value as “C”. This is the value for the peaks in either mode.

(e)

(1) If multiple smokemeters were used, the half-second values for each mode from each smokemeter shall be combined and the calculated average based upon the total number of combined values.

(2) For example, if two smokemeters were used for acceleration mode data, 45 half-second values in each data set from both smokemeters would be combined to form a data set of 90 values, which would then be averaged.

[62 FR 47123, Sept. 5, 1997, as amended at 69 FR 2441, Jan. 15, 2004]

Title 40 published on 2015-07-01

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

• 2015-09-08; vol. 80 # 173 - Tuesday, September 8, 2015
1. 80 FR 53756 - Greenhouse Gas Emissions and Fuel Efficiency Standards for Medium- and Heavy-Duty Engines and Vehicles—Phase 2; Extension of Comment Period
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DEPARTMENT OF TRANSPORTATION, ENVIRONMENTAL PROTECTION AGENCY, National Highway Traffic Safety Administration
Proposed rule; extension of comment period.
The comment period for the proposed rule published July 13, 2015 (80 FR 40139) is extended. Written comments for both documents must be received on or before October 1, 2015.
40 CFR Parts 9, 22, 85, 86, 600, 1033, 1036, 1037, 1039, 1042, 1065, 1066, and 1068