Document ID: chunk:federal_register_of_legislation:F2011C00805:reg:120:p8
Version: federal_register_of_legislation:F2011C00805
Segment Type: reg
Provision Reference: reg 120 (pt 8/23)
Character Range: 255078–258019

equipment consists of:

         3.1.3.1. a filter (D) for the dilution air, which can be preheated if necessary. This filter shall consist of activated charcoal sandwiched between two layers of paper, and shall be used to reduce and stabilise the hydrocarbon concentrations of ambient emissions in the dilution air;

         3.1.3.2. a mixing chamber (M) in which exhaust gas and air are mixed homogeneously;

         3.1.3.3. a heat exchanger (H) of a capacity sufficient to ensure that throughout the test the temperature of the air/exhaust-gas mixture measured at a point immediately upstream of the positive displacement pump is within 6 K of the designed operating temperature. This device shall not affect the pollutant concentrations of diluted gases taken off after for analysis;

         3.1.3.4. a temperature control system (TC), used to preheat the heat exchanger before the test and to control its temperature during the test, so that deviations from the designed operating temperature are limited to 6 K;

         3.1.3.5. the positive displacement pump (PDP), producing a constant-volume flow of the air/exhaust-gas mixture; the flow capacity of the pump shall be large enough to eliminate water condensation in the system under all operating conditions which may occur during a test; this can be generally ensured by using a positive displacement pump with a flow capacity:

         3.1.3.5.1. twice as high as the maximum flow of exhaust gas produced by accelerations of the driving cycle, or

         3.1.3.5.2.  sufficient to ensure that the CO2 concentration in the dilute-exhaust sample bag is less than 3 per cent by volume for petrol and diesel, less than 2.2 per cent by volume for LPG and less than 1.5 per cent by volume for NG.

         3.1.3.6.  A temperature sensor (T1), (accuracy and precision  0.4 kPa), fitted immediately upstream of the volume meter and used to register the pressure difference between the gas mixture and the ambient air;

         3.1.3.7.  A pressure gauge (G1),(accuracy and precision  0.4 kPa), fitted immediately upstream of the positive displacement pump and used to register the pressure gradient between the gas mixture and the ambient air;

         3.1.3.8.  Another pressure gauge (G2),accuracy and precision  0.4 kPa), fitted so that the differential pressure between pump inlet and pump outlet can be registered;

         3.1.3.9. Two sampling probes (S1 and S2) for continuous sampling of the dilution air and of the diluted exhaust-gas/air mixture;

         3.1.3.10.  A filter (F), to extract solid particles from the flows of gas collected for analysis;

         3.1.3.11.  Pumps (P), to collect a constant flow of 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