§ 1066.1001 Definitions.
The definitions in this section apply to this part. The definitions apply to all subparts unless we note otherwise. Other terms have the meaning given in 40 CFR part 1065. The definitions follow:
Average means the arithmetic mean of a sample.
Bag 1 means relating to the first 505 seconds of the FTP cold-start test interval. Note that the term bag 1 may also apply to measurement of constituents that are not collected in a bag, such as PM and continuously measured THC.
Bag 2 means relating to the last 867 seconds of the FTP cold-start test interval.
Bag 3 means relating to the first 505 seconds of the FTP hot-start test interval.
Bag 4 means relating to the last 867 seconds of the FTP hot-start test interval, if run. Note that bag 2 is generally used in place of bag 4.
Base inertia means a value expressed in mass units to represent the rotational inertia of the rotating dynamometer components between the vehicle driving tires and the dynamometer torque-measuring device, as specified in § 1066.250.
C1-equivalent means a convention of expressing HC concentrations based on the total number of carbon atoms present, such that the C1-equivalent of an HC concentration equals the concentration multiplied by the mean number of carbon atoms in each HC molecule. For example, the C1-equivalent of 10 ppm of propane (C3H8) is 30 ppm. C1-equivalent concentration values may be denoted as “ppmC” in the standard-setting part. Densities may also be expressed on a C1 basis. Note that calculating HC masses from concentrations and densities is only valid where they are each expressed on the same carbon basis.