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

Title 40Chapter ISubchapter UPart 1066Subpart B → §1066.125

Title 40: Protection of Environment
Subpart B—Equipment, Measurement Instruments, Fuel, and Analytical Gas Specifications

§1066.125   Data updating, recording, and control.

This section specifies criteria that your test system must meet for updating and recording data. It also specifies criteria for controlling the systems related to driver demand, the dynamometer, sampling equipment, and measurement instruments.

(a) Read and record values and calculate mean values relative to a specified frequency as follows:

(1) This paragraph (a)(1) applies where we specify a minimum command and control frequency that is greater than the minimum recording frequency, such as for sample flow rates from a CVS that does not have a heat exchanger. For these measurements, the rate at which you read and interpret the signal must be at least as frequent as the minimum command and control frequency. You may record values at the same frequency, or you may record them as mean values, as long as the frequency of the mean values meets the minimum recording frequency. You must use all read values, either by recording them or using them to calculate mean values. For example, if your system reads and controls the sample flow rate at 10 Hz, you may record these values at 10 Hz, record them at 5 Hz by averaging pairs of consecutive points together, or record them at 1 Hz by averaging ten consecutive points together.

(2) For all other measured values covered by this section, you may record the values instantaneously or as mean values, consistent with good engineering judgment.

(3) You may not use rolling averages of measured values where a given measured value is included in more than one recorded mean value.

(b) Use data acquisition and control systems that can command, control, and record at the following minimum frequencies:

Table 1 of §1066.125—Data Recording and Control Minimum Frequencies

Applicable sectionMeasured valuesMinimum command and control frequencyaMinimum recording frequencyb c
Vehicle speed10 Hz.
§1066.425Continuous concentrations of raw or dilute analyzers1 Hz.
Power analyzer1 Hz.
§1066.425Bag concentrations of raw or dilute analyzers1 mean value per test interval.
40 CFR 1065.545
Diluted exhaust flow rate from a CVS with a heat exchanger upstream of the flow measurement1 Hz.
40 CFR 1065.545
Diluted exhaust flow rate from a CVS without a heat exchanger upstream of the flow measurement5 Hz1 Hz means.
40 CFR 1065.545
Dilution air flow if actively controlled (for example, a partial-flow PM sampling system)d5 Hz1 Hz means.
40 CFR 1065.545
Sample flow from a CVS that has a heat exchanger1 Hz1 Hz.
40 CFR 1065.545
Sample flow from a CVS that does not have a heat exchanger5 Hz1 Hz means.
§1066.420Ambient temperature1 Hz.e
§1066.420Ambient humidity1 Hz.e
§1066.420Heated sample system temperatures, including PM filter face1 Hz.

aCFVs that are not using active control are exempt from meeting this requirement due to their operating principle.

b1 Hz means are data reported from the instrument at a higher frequency, but recorded as a series of 1 s mean values at a rate of 1 Hz.

cFor CFVs in a CVS, the minimum recording frequency is 1 Hz. For CFVs used to control sampling from a CFV CVS, the minimum recording frequency is not applicable.

dThis is not applicable to CVS dilution air.

eUnless specified elsewhere in this part or the standard-setting part. Note that this provision does not apply to soak periods where recording frequencies are not specified. For these instances, we recommend a recording frequency of ≥0.016 Hz.

[79 FR 23823, Apr. 28, 2014, as amended at 80 FR 9120, Feb. 19, 2015]

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