Document ID: chunk:federal_register_of_legislation:F2023L00129:reg:1800:p7
Version: federal_register_of_legislation:F2023L00129
Segment Type: reg
Provision Reference: reg 1800 (pt 7/12)
Character Range: 521318–524024

sampling system;
(b) Shall be constructed of stainless steel;
(c) May be heated to no greater than 325 K (52 °C) wall temperature;
(d) May be insulated.
 PSP Particulate sampling probe (fractional sampling type, Figure 13 only)
 The particulate sampling probe is the leading section of the particulate transfer tube PTT (see paragraph A.2.2.6.) and:
(a) Shall be installed facing upstream at a point where the diluent and exhaust gas are well mixed, i.e. on the dilution tunnel DT centreline approximately 10 tunnel diameters downstream of the point where the exhaust enters the dilution tunnel;
(b) Shall be 8 mm in minimum inside diameter;
(c) May be heated to no greater than 325 K (52 °C) wall temperature by direct heating or by diluent pre‑heating, provided the diluent temperature does not exceed 325 K (52 °C) prior to the introduction of the exhaust into the dilution tunnel;
(d) May be insulated.
A.2.2.3. Description of full flow dilution system
 A dilution system is described based upon the dilution of the total amount of raw exhaust gas in the dilution tunnel DT using the CVS (constant volume sampling) concept, and is shown in Figure 15.
 The diluted exhaust gas flow rate shall be measured either with a positive displacement pump (PDP), with a critical flow venturi (CFV) or with a subsonic venturi (SSV). A heat exchanger (HE) or electronic flow compensation (EFC) may be used for proportional particulate sampling and for flow determination. Since particulate mass determination is based on the total diluted exhaust gas flow, it is not necessary to calculate the dilution ratio.
 For subsequent collection of the particulates, a sample of the dilute exhaust gas shall be passed to the double dilution particulate sampling system (see Figure 17). Although partly a dilution system, the double dilution system is described as a modification of a particulate sampling system, since it shares most of the parts with a typical particulate sampling system.
              Figure 15
              Scheme of full flow dilution system (CVS)
              a = analyzer system b = background air c = exhaust d = details see Figure 17
              e = to double dilution system f = if EFC is used i = vent g = optional h = or

A.2.2.4. Components of Figure 15
 EP Exhaust pipe
 The exhaust pipe length from the exit of the engine exhaust manifold, turbocharger outlet or after-treatment device to the dilution tunnel shall be not more than 10 m. If the system exceeds 4 m in length, then all tubing in excess of 4 m shall be insulated, except for an in-line smoke meter, if used. The radial thickness of the insulation shall be at least 25 mm. The thermal conductivity of the insulating material