Document ID: chunk:federal_register_of_legislation:F2024L00446:reg:16:p41
Version: federal_register_of_legislation:F2024L00446
Segment Type: reg
Provision Reference: reg 16 (pt 41/108)
Character Range: 999353–1002392

than at the external piping on the pump inlet and outlet. Pressure taps that are mounted at the top centre and bottom centre of the pump drive head plate are exposed to the actual pump cavity pressures, and therefore reflect the absolute pressure differentials.
              3.4.2.2.2. Temperature stability shall be maintained during the calibration. The laminar flow meter is sensitive to inlet temperature oscillations that cause data points to be scattered. Gradual changes of ±1 °C in temperature are acceptable as long as they occur over a period of several minutes.
              3.4.2.2.3. All connections between the flow meter and the CVS pump shall be free of leakage.
              3.4.2.3. During an exhaust emissions test, the measured pump parameters shall be used to calculate the flow rate from the calibration equation.
              3.4.2.4. Figure A5/6 of this annex shows an example of a calibration set-up. Variations are permissible, provided that the responsible authority approves them as being of comparable accuracy. If the set-up shown in Figure A5/6 is used, the following data shall be found within the limits of accuracy given:
           Barometric pressure (corrected),  ±0.03 kPa
           Ambient temperature,  ±0.2 °C
           Air temperature at LFE, ETI ±0.15 °C
           Pressure depression upstream of LFE, EPI ±0.01 kPa
           Pressure drop across the LFE matrix, EDP ±0.0015 kPa
           Air temperature at CVS pump inlet, PTI ±0.2 °C
           Air temperature at CVS pump outlet, PTO ±0.2 °C
           Pressure depression at CVS pump inlet, PPI ±0.22 kPa
           Pressure head at CVS pump outlet, PPO ±0.22 kPa
           Pump revolutions during test period,  ±1 min-1
           Elapsed time for period (minimum 250 s), t ±0.1 s
           Figure A5/6
           PDP calibration configuration

              3.4.2.5. After the system has been connected as shown in Figure A5/6, the variable restrictor shall be set in the wide-open position and the CVS pump shall run for 20 minutes before starting the calibration.
              3.4.2.5.1. The restrictor valve shall be reset to a more restricted condition in increments of pump inlet depression (about 1 kPa) that will yield a minimum of six data points for the total calibration. The system shall be allowed to stabilize for 3 minutes before the data acquisition is repeated.
              3.4.2.5.2. The air flow rate Qs at each test point shall be calculated in standard m3/min from the flow meter data using the manufacturer's prescribed method.
              3.4.2.5.3. The air flow rate shall be subsequently converted to pump flow  in m3/rev at absolute pump inlet temperature and pressure.
           where:
           V0 is the pump flow rate at Tp and Pp, m3/rev;
           Qs is the air flow at 101.325 kPa and 273.15 K (0 °C), m3/min;
           Tp is the pump inlet temperature, Kelvin (K);
           Pp is the absolute pump inlet pressure, kPa;
           n is the pump speed, min-1.
              3.4.2.5.4. To