Home
gpo.gov
govinfo.gov

e-CFR Navigation Aids

Browse

Simple Search

Advanced Search

 — Boolean

 — Proximity

 

Search History

Search Tips

Corrections

Latest Updates

User Info

FAQs

Agency List

Incorporation By Reference

eCFR logo

Related Resources

Electronic Code of Federal Regulations

We invite you to try out our new beta eCFR site at https://ecfr.federalregister.gov. We have made big changes to make the eCFR easier to use. Be sure to leave feedback using the Feedback button on the bottom right of each page!

e-CFR data is current as of November 25, 2020

Title 40Chapter ISubchapter UPart 1066Subpart G → §1066.610


Title 40: Protection of Environment
PART 1066—VEHICLE-TESTING PROCEDURES
Subpart G—Calculations


§1066.610   Dilution air background correction.

(a) Correct the emissions in a gaseous sample for background using the following equation:

eCFR graphic er28ap14.099.gif

View or download PDF

Where:

x[emission]dexh = measured emission concentration in dilute exhaust (after dry-to-wet correction, if applicable).

x[emission]bkgnd = measured emission concentration in the dilution air (after dry-to-wet correction, if applicable).

DF = dilution factor, as determined in paragraph (b) of this section.

eCFR graphic er28ap14.100.gif

View or download PDF

Where:

xCO2 = amount of CO2 measured in the sample over the test interval.

xNMHC = amount of C1-equivalent NMHC measured in the sample over the test interval.

xCH4 = amount of CH4 measured in the sample over the test interval.

xCO = amount of CO measured in the sample over the test interval.

α = atomic hydrogen-to-carbon ratio of the test fuel. You may measure α or use default values from Table 1 of 40 CFR 1065.655.

β = atomic oxygen-to-carbon ratio of the test fuel. You may measure β or use default values from Table 1 of 40 CFR 1065.655.

eCFR graphic er28ap14.101.gif

View or download PDF

(c) Determine the dilution factor, DF, over the test interval for partial-flow dilution sample systems using the following equation:

eCFR graphic er28ap14.152.gif

View or download PDF

Where:

Vdexhstd = total dilute exhaust volume sampled over the test interval, corrected to standard reference conditions.

Vexhstd = total exhaust volume sampled from the vehicle, corrected to standard reference conditions.

eCFR graphic er28ap14.102.gif

View or download PDF

(d) Determine the time-weighted dilution factor, DFw, over the duty cycle using the following equation:

eCFR graphic er28ap14.103.gif

View or download PDF

Where:

N = number of test intervals.

i = test interval number

t = duration of the test interval.

DF = dilution factor over the test interval.

Example:    

eCFR graphic er28ap14.104.gif

View or download PDF

Need assistance?