Document ID: chunk:federal_register_of_legislation:F2011C00805:reg:120:p9
Version: federal_register_of_legislation:F2011C00805
Segment Type: reg
Provision Reference: reg 120 (pt 9/23)
Character Range: 257776–260992

the dilution air as well as of the diluted exhaust-gas/air mixture during the test;

         3.1.3.12.  Flow controllers (N), to ensure a constant uniform flow of the gas samples taken during the course of the test from sampling probes S1 and S2 and flow of the gas samples shall be such that, at the end of each test, the quantity of the samples is sufficient for analysis (approx. 10 litres per minute);

         3.1.3.13. Flow meters (FL), for adjusting and monitoring the constant flow of gas samples during the test;

         3.1.3.14.  Quick-acting valves (V), to divert a constant flow of gas samples into the sampling bags or to the outside vent;

         3.1.3.15.  Gas-tight, quick-lock coupling elements (Q) between the quick-acting valves and the sampling bags; the coupling shall close automatically on the sampling-bag side; as an alternative, other ways of transporting the samples to the analyser may be used (three-way stopcocks, for instance);

         3.1.3.16.  Bags (B), for collecting samples of the diluted exhaust gas and of the dilution air during the test; they shall be of sufficient capacity not to impede the sample flow; the bag material shall be such as to affect neither the measurements themselves nor the chemical composition of the gas samples (for instance: laminated polyethylene/polyamide films, or fluorinated polyhydrocarbons);

         3.1.3.17.  A digital counter (C), to register the number of revolutions performed by the positive displacement pump during the test.

         3.1.4. Additional equipment required when testing compression-ignition-engined vehicles

         To comply with the requirements of paragraphs 4.3.1.1. and 4.3.2. of Annex 4, the additional components within the dotted lines in Figure 5/3 shall be used when testing compression-ignition-engined vehicles:

                   Fh  is a heated filter,

                   S3  is a hydrocarbon sampling point,

                   Vh  is a heated multi-way valve,

                   Q  is a quick connector to allow the ambient air sample BA to be analysed on the HFID,

                   HFID   is a heated flame ionisation analyser,

                   R and I  are a means of integrating and recording the instantaneous hydrocarbon concentrations,

                   Lh  is a heated sample line.

         All heated components shall be maintained at 463 K (190 C)  10 K.

         Particulate sampling system:

               S4 Sampling probe in the dilution tunnel,

               Fp Filter unit consisting of two series-mounted filters; switching arrangement for further parallel-mounted pairs of filters,

         Sampling line,

         Pumps, flow regulators, flow measuring units.

         3.2.  Critical-flow venturi dilution device (CFV-CVS) (Figure 5/4)

         3.2.1. The use of a critical-flow venturi in connection with the CVS sampling procedure is based on the principles of flow mechanics for critical flow. The variable mixture flow rate of dilution and exhaust gas is maintained at sonic velocity which is directly proportional to the square root of the gas temperature. Flow is continually monitored, computed and integrated throughout the test.

         The