92.125 Pre-test procedures and preconditioning.§ 92.125 Pre-test procedures and preconditioning.
(a) Locomotive testing. (1) Determine engine lubricating oil and coolant levels and fill as necessary to manufacturers recommended full levels.
(2) Connect fuel supply system and purge as necessary; determine that the fuel to be used during emission testing is in compliance with the specifications of § 92.113.
(3) Install instrumentation, engine loading equipment and sampling equipment as required.
(4) Operate the engine until it has reached the specified operating temperature.
(b) Engine testing. (1) Determine engine lubricating oil level and fill as necessary to manufacturers recommended full level.
(2)(i) Connect fuel supply system and purge as necessary; determine that the fuel to be used during emission testing is in compliance with the specifications of § 92.113.
(ii) Connect engine cooling system.
(3) Install instrumentation, and sampling equipment as required. Couple the engine to the dynamometer or locomotive alternator/generator.
(4) Start cooling system.
(5) Operate the engine until it has reached the specified operating temperature.
(6) Establish that the temperature of intake air entering the engine after compression and cooling in the charge air cooler(s), at each test point, is within ±5 °F of the temperatures which occur in locomotive operations at the ambient temperature represented by the test.
(c) Both locomotive and engine testing. (1) Allow a minimum of 30 minutes warm-up in the stand-by or operating mode prior to spanning the analyzers.
(2) Replace or clean filter elements (sampling and analytical systems) as necessary, and then vacuum leak check the system, § 92.118. A pressure leak check is also permitted per § 92.118. Allow the heated sample line, filters, and pumps to reach operating temperature.
(3) Perform the following system checks:
(i) If a stainless steel NO2 to NO converter is used, purge the converter with air (zero-grade air, room air, or O2) for a minimum of 30 minutes. The converter must be at operational temperature while purging.
(ii) Check the sample system temperatures (see § 92.114).
(iii) Check the system response time (see § 92.118). System response time may be applied from the most recent check of response time if all of the following are met:
(A) The flow rate for each flow meter is equal to or greater than the flow rate recorded in § 92.118.
(B) For analyzers with capillaries, the response time from the sample/span valve is measured using in-use pressures and bypass flows (see § 92.118).
(C) The response time measured in step in paragraph (c)(3)(iii)(B) of this section is equal to or less than the slowest response time determined for Capillary flow analyzers in § 92.118 plus 2 seconds.
(iv) A hang-up check is permitted.
(v) A converter-efficiency check is permitted. The check need not conform to § 92.121. The test procedure may be aborted at this point in the procedure in order to repair the NO2 to NO converter. If the test is aborted, the converter must pass the efficiency check described in § 92.121 prior to starting the test run.
(4) Introduce the zero-grade gases at the same flow rates and pressures used to calibrate the analyzers and zero the analyzers on the lowest anticipated range that will be used during the test. Immediately prior to each test, obtain a stable zero for each anticipated range that will be used during the test.
(5) Introduce span gases to the instruments under the same flow conditions as were used for the zero gases. Adjust the instrument gains on the lowest range that will be used to give the desired value. Span gases should have a concentration greater than 70 percent of full scale for each range used. Immediately prior to each test, record the response to the span gas and the span-gas concentration for each range that will be used during the test.
(6) Check the zero responses. If they have changed more than 0.5 percent of full scale, repeat paragraphs (c)(4) and (5) of this section.
(7) Check system flow rates and pressures. Note the values of gauges for reference during the test.