(i) An apparatus for measuring torque that provides an accuracy of ±2.0 percent based on the engine's maximum value;

(ii) An apparatus for measuring revolutions per minute (rpm) that provides an accuracy of ±2.0 percent based on the engine's maximum value;

(iii) An apparatus for measuring temperature that provides an accuracy of ±4 °F (2 °C) of the absolute value except for the exhaust gas temperature device that provides an accuracy of ±27 °F (15 °C);

(iv) An apparatus for measuring intake and exhaust restriction pressures that provides an accuracy of ±5 percent of maximum;

(v) An apparatus for measuring atmospheric pressure that provides an accuracy of ±0.5 percent of reading;

(vi) An apparatus for measuring fuel flow that provides an accuracy of ±2 percent based on the engine's maximum value;

(vii) An apparatus for measuring the inlet air flow rate of the diesel engine that provides an accuracy of ±2 percent based on the engine's maximum value; and

(viii) For testing category A engines, an apparatus for metering in 1.0 ±0.1 percent, by volume, of methane (CH₄) into the intake air system shall be provided.

(i) Filters - F1, F2, F3, and F4;

(ii) Flowmeters - FL1, FL2, FL3, FL4, FL5, FL6, and FL7;

(iii) Upstream Gauges - G1, G2, and G5;

(iv) Downstream Gauges - G3, G4, and G6;

(v) Pressure Gauges - P1, P2, P3, P4, P5, and P6;

(vi) Regulators - R1, R2, R3, R4, R5, R6, and R7;

(vii) Selector Valves - V1, V2, V3, V4, V6, V7, V8, V15, and V19;

(viii) Heated Selector Valves - V5, V13, V16, and V17;

(ix) Flow Control Valves - V9, V10, V11 and V12;

(x) Heated Flow Control Valves - V14 and V18;

(xi) Pump - Sample Transfer Pump;

(xii) Temperature Sensor - (T1);

(xiii) Dryer - D1 and D2; and

(xiv) Water traps - WT1 and WT2.

(C) Chemical dryers are not permitted.

(i) Filters - F1, F2, F3, and F4;

(ii) Flowmeters - FL1, FL2, FL3, and FL4;

(iii) Upstream Gauges - G1, and G2;

(iv) Downstream Gauges - G3, and G4;

(v) Pressure Gauges - P1, P2, P3, and P4;

(vi) Regulators - R1, R2, R3, and R4;

(vii) Selector Valves - V1, V2, V3, V4, V6, and V7;

(viii) Heated Selector Valves - V5, V8, and V12;

(ix) Flow Control Valves - V9, V10, V11;

(x) Heated Flow Control Valves - V13;

(xi) Pump - Sample Transfer Pump;

(xii) Temperature Sensor - (T1); and

(xiii) Water traps - WT1 and WT2.

(i) The probe length shall be at least 80 percent of the diameter of the exhaust pipe.

(ii) The inside diameter of the sample probe shall not be greater than the inside diameter of the sample line.

(iii) The heated sample line shall have a 0.197 inch (5 mm) minimum and a 0.53 inch (13.5 mm) maximum inside diameter.

(iv) The wall thickness of the probe shall not be greater than 0.040 inch (1 mm).

(v) There shall be a minimum of 3 holes in 3 different radial planes sized to sample approximately the same flow.

(i) The total measurement error, including the cross sensitivity to other gases, (paragraphs (b)(11)(ii), (b)(12)(iii), (b)(13)(iii), and (b)(13)(iv) of this section), shall not exceed ±5 percent of the reading or ±3.5 percent of full scale, whichever is smaller. For concentrations of less than 100 ppm the measurement error shall not exceed ±4 ppm.

(ii) The repeatability, defined as 2.5 times the standard deviation of 10 repetitive responses to a given calibration or span gas, must be no greater than ±1 percent of full scale concentration for each range used above 155 parts per million (ppm) or parts per million equivalent carbon (ppmC) or ±2 percent of each range used below 155 ppm (or ppmC).

(iii) The analyzer peak to peak response to zero and calibration or span gases over any 10 second period shall not exceed 2 percent of full scale on all ranges used.

(iv) The analyzer zero drift during a 1-hour period shall be less than 2 percent of full scale on the lowest range used. The zero-response is the mean response, including noise, to a zero gas during a 30-second time interval.

(v) The analyzer span drift during a 1-hour period shall be less than 2 percent of full scale on the lowest range used. The analyzer span is defined as the difference between the span response and the zero response. The span response is the mean response, including noise, to a span gas during a 30-second time interval.

(i) Measurements shall be made with nondispersive infrared (NDIR) analyzers.

(ii) For the CO analyzer, the water and CO₂ interference shall be less than 1 percent of full scale for ranges equal to or greater than 300 ppm (3 ppm for ranges below 300 ppm) when a CO₂ span gas concentration of 80 percent to 100 percent of full scale of the maximum operating range used during testing is bubbled through water at room temperature.

(i) From the sample point to the NO₂ to NO converter, the NO_X sample shall be maintained between 131 °F (55 °C) and 392 °F (200 °C).

(ii) The NO₂ to NO converter efficiency shall be at least 90 percent.

(iii) The quench interference from CO₂ and water vapor must be less than 3.0 percent.

(i) The system shall include a NO₂ to NO converter, a water trap, and a NDIR analyzer.

(ii) From the sample point to the NO₂ to NO converter, the NO_X sample shall be maintained between 131 °F (55 °C) and 392 °F (200 °C).

(iii) The minimum water rejection ratio (maximum water interference) for the NO_X NDIR analyzer shall be 5,000:1.

(iv) The minimum CO₂ rejection ratio (maximum CO₂ interference) for the NO_X NDIR analyzer shall be 30,000:1.

(i) The analyzer shall be equipped with a constant temperature oven that houses the detector and sample-handling components.

(ii) The detector, oven, and sample-handling components shall be suitable for continuous operation at temperatures of 374 °F (190 °C) ±18 °F (10 °C).

(iii) The analyzer fuel shall contain 40 ±2 percent hydrogen. The balance shall be helium. The mixture shall contain ≤1 part per million equivalent carbon (ppmC), and ≤400 ppm CO.

(iv) The burner air shall contain <2 ppmC hydrocarbon.

(v) The percent of oxygen interference shall be less than 5 percent.

(i) Either a positive displacement pump (PDP) or a critical flow venturi (CFV) shall be used as the pump/mass measurement device shown in Figure E-3.

(ii) The total volume of the mixture of exhaust and dilution air shall be measured.

(iii) All parts of the system from the exhaust pipe up to the filter holder, which are in contact with raw and diluted exhaust gas, shall be designed to minimize deposition or alteration of the particulate.

(iv) All parts shall be made of electrically conductive materials that do not react with exhaust gas components.

(v) All parts shall be electrically grounded to prevent electrostatic effects.

(vi) Systems other than full flow systems may also be used provided they yield equivalent results where:

(i) Using PDP, the gas mixture temperature shall be maintained within ±10 °F (6.0 °C) of the average operating temperature observed during the test, when no flow compensation is used.

(ii) Flow compensation can be used provided that the temperature at the inlet to the PDP does not exceed 122 °F (50 °C).

(iii) Using CFV, the gas mixture temperature shall be maintained within ±20 °F (11 °C) of the average operating temperature observed during the test, when no flow compensation is used.

(i) Filtered at the air inlet; or

(ii) Sampled to determine background particulate levels, which can then be subtracted from the values measured in the exhaust stream.

(i) Be small enough in diameter to cause turbulent flow (Reynolds number greater than 4,000) and of sufficient length to cause complete mixing of the exhaust and dilution air;

(ii) Be at least 3 inches (75 mm) in diameter; and

(iii) Be configured to direct the engine exhaust downstream at the point where it is introduced into the dilution tunnel for thorough mixing.

(i) When the exhaust pipe exceeds 12 feet (4 m), then all pipe in excess of 12 feet (4 m) shall be insulated with a radial thickness of at least 1.0 inch (25 mm) and the thermal conductivity of the insulating material shall be no greater than 0.1 W/mK measured at 752 °F (400 °C).

(ii) To reduce the thermal inertia of the exhaust pipe, the thickness to diameter ratio shall be 0.015 or less.

(iii) The use of flexible sections shall be limited to the length to diameter ratio of 12 or less.

(i) Be installed in the dilution tunnel facing upstream, on the dilution tunnel centerline, and approximately 10 dilution tunnel diameters downstream of the point where the engine's exhaust enters the dilution tunnel; and

(ii) Have 0.5 inches (12 mm) minimum inside diameter.

(i) A particulate transfer tube shall have a 0.5 inch (12 mm) minimum inside diameter not to exceed 40 inches (1020 mm) in length measured from the probe tip to the secondary dilution tunnel has:

(ii) A secondary tunnel that has a minimum diameter of 3.0 inches (75 mm), and of sufficient length to provide a residence time of at least 0.25 seconds for the double-diluted sample.

(iii) Secondary dilution air supplied at a temperature of 77 °F ±9 °F (25 °C ±5 °C).

(iv) A primary filter holder located within 12.0 inches (300 mm) of the exit of the secondary tunnel.

(i) Be fluorocarbon-coated glass fiber filters or fluorocarbon-based (membrane) filters and have a 0.3 µm di-octylphthalate (DOP) collection efficiency of at least 95 percent at a gas face velocity between 35 and 80 cm/s.;

(ii) Have a minimum diameter of 1.85 inches (47 mm), 1.46 inches (37 mm) stain diameter;

(iii) Have a minimum filter loading ratio of 0.5mg/1075 mm² stain area for the single filter method.

(iv) Have minimum filter loading such that the sum of all eight (8) multiple filters is equal to the minimum loading value (mg) for a single filter multiplied by the square root of eight (8).

(v) Be sampled at the same time by a pair of filters in series (one primary and one backup filter) so that:

(vi) Have a pressure drop increase between the beginning and end of the test of no more than 7.4 in Hg (25kPa).

(vii) Filters of identical quality shall be used when performing correlation tests specified in paragraph (c)(1)(vi) of this section.

(i) The temperature of the chamber (room) in which the particulate filters are conditioned and weighed shall be maintained to within 72 °F ±5 °F (22 °C ±3 °C) during all filter conditioning and weighing.

(ii) The humidity of the chamber (room) in which the particulate filters are conditioned and weighed shall be maintained to a dewpoint of 49 °F ±5 °F (9.5 °C ±3 °C) and a relative humidity of 45 percent ±8 percent during all filter conditioning and weighing.

(iii) The chamber (room) environment shall be free of any ambient contaminants (such as dust) that would settle on the particulate filters during their stabilization. This shall be determined as follows: