Document ID: chunk:federal_register_of_legislation:F2023L00129:reg:10:p17
Version: federal_register_of_legislation:F2023L00129
Segment Type: reg
Provision Reference: reg 10 (pt 17/150)
Character Range: 761471–764635

drift-corrected emission results shall be used when reporting emissions.
       A.1.2.7.6. Checking the PM number analyser

              The zero level of the PM number analyser shall be checked before test start and after test end and recorded in accordance with the requirements of paragraph A.1.2.5.5.

A.1.3. Calculation of the emissions
              The final test result shall be rounded in one step to the number of places to the right of the decimal point indicated by the applicable emission standard plus one additional significant figure, in accordance with ASTM E 29-06b. No rounding of intermediate values leading to the final brake-specific emission result shall be allowed.
              A.1.3.1. Time alignment of data
              To minimize the biasing effect of the time lag between the different signals on the calculation of mass emissions, the data relevant for emissions calculation shall be time aligned, as described in paragraphs A.1.3.1.1. to A.1.3.1.4.
       A.1.3.1.1. Analysers data

              The data from the gas analysers shall be properly aligned using the procedure laid down in paragraph 9.3.5. of Annex 4. The data from the PM number analyser shall be time aligned with its own transformation time, according to the instrument manufacturer's instructions.

              A.1.3.1.2. Analysers and Exhaust Flow Meter (EFM) data

              The data from the gas analysers and the PM number analysers shall be properly aligned with the data of the EFM using the procedure in paragraph A.1.3.1.4.

              A.1.3.1.3. PEMS and engine data

              The data from the PEMS (gas analysers, PM number analyser and EFM) shall be properly aligned with the data from the engine ECU using the procedure in paragraph A.1.3.1.4.
       A.1.3.1.4. Procedure for improved time-alignment of the PEMS data

              The test data listed in Table 1 are split into 3 different categories:

                  1. Gas analysers (THC, CO, CO2, NOx concentrations) and PM number analyser;

              2. Exhaust Flow Meter (Exhaust mass flow and exhaust temperature);

                  3. Engine (Torque, speed, temperatures, fuel rate, vehicle speed from ECU).

              The time alignment of each category with the other categories shall be verified by finding the highest correlation coefficient between two series of parameters. All the parameters in a category shall be shifted to maximize the correlation factor. The following parameters shall be used to calculate the correlation coefficients:

              To time-align:

                  (a) Categories 1 and 2 (Analyzers and EFM data) with category 3 (Engine data): the vehicle speed from the GPS and from the ECU;

                  (b) Category 1 with category 2: the CO2 concentration and the exhaust mass;

                  (c) Category 2 with category 3: the CO2 concentration and the engine fuel flow."

              A.1.3.2. Data consistency checks
A.1.3.2.1. Analysers and EFM data
The consistency of the data (exhaust mass flow measured by the EFM and gas concentrations) shall be verified using a correlation between the measured fuel flow