40 CFR 89.407 - Engine dynamometer test run.
(a) Measure and record the temperature of the air supplied to the engine, the fuel temperature, the intake air humidity, and the observed barometric pressure during the sampling for each mode. The fuel temperature shall be less than or equal to 43C during the sampling for each mode.
(b) The governor and fuel system shall have been adjusted to provide engine performance at the levels reported in the application for certification required under § 89.115.
(c) The following steps are taken for each test:
(1) Install instrumentation and sample probes as required.
(2) Perform the pre-test procedure as specified in § 89.406.
(3) Read and record the general test data as specified in § 89.405(c).
(4) Start cooling system.
(5) Precondition (warm up) the engine in the following manner:
(i) For variable-speed engines:
(A) Operate the engine at idle for 2 to 3 minutes;
(B) Operate the engine at approximately 50 percent power at the peak torque speed for 5 to 7 minutes;
(C) Operate the engine at rated speed and maximum horsepower for 25 to 30 minutes;
(ii) For constant-speed engines:
(A) Operate the engine at minimum load for 2 to 3 minutes;
(B) Operate the engine at 50 percent load for 5 to 7 minutes;
(C) Operate the engine at maximum load for 25 to 30 minutes;
(iii) Optional. It is permitted to precondition the engine at rated speed and maximum horsepower until the oil and water temperatures are stabilized. The temperatures are defined as stabilized if they are maintained within 2 percent of point on an absolute basis for 2 minutes. The engine must be operated a minimum of 10 minutes for this option. This optional procedure may be substituted for the procedure in paragraph (c)(5)(i)or (c)(5)(ii) of this section;
(iv) Optional. If the engine has been operating on service accumulation for a minimum of 40 minutes, the service accumulation may be substituted for the procedure in paragraphs (c)(5)(i) through (iii) of this section.
(6) Read and record all pre-test data specified in § 89.405(d).
(7) Start the test cycle (see § 89.410) within 20 minutes of the end of the warmup. (See paragraph (c)(13) of this section.) A mode begins when the speed and load requirements are stabilized to within the requirements of § 89.410(b). A mode ends when valid emission sampling for that mode ends. For a mode to be valid, the speed and load requirements must be maintained continuously during the mode. Sampling in the mode may be repeated until a valid sample is obtained as long the speed and torque requirements are met.
(8) Calculate the torque for any mode with operation at rated speed.
(9) During the first mode with intermediate speed operation, if applicable, calculate the torque corresponding to 75 and 50 percent of the maximum observed torque for the intermediate speed.
(10) Record all modal data specified in § 89.405(e) during a minimum of the last 60 seconds of each mode.
(11) Record the analyzer(s) response to the exhaust gas during the a minimum of the last 60 seconds of each mode.
(12) Test modes may be repeated, as long as the engine is preconditioned by running the previous mode. In the case of the first mode of any cycle, precondition according to paragraph (c)(5) of this section.
(13) If a delay of more than 20 minutes, but less than 4 hours, occurs between the end of one mode and the beginning of another mode, precondition the engine by running the previous mode. If the delay exceeds 4 hours, the test shall include preconditioning (begin at paragraph (c)(2) of this section).
(14) The speed and load points for each mode are listed in Tables 1 through 4 of Appendix B of this subpart. The engine speed and load shall be maintained as specified in § 89.410(b).
(15) If at any time during a test mode, the test equipment malfunctions or the specifications in paragraph (c)(14) of this section are not met, the test mode is void and may be aborted. The test mode may be restarted by preconditioning with the previous mode.
(16) Fuel flow and air flow during the idle load condition may be determined just prior to or immediately following the dynamometer sequence, if longer times are required for accurate measurements.
(d) Exhaust gas measurements.
(1) Measure HC, CO, CO2, and NOX concentrations in the exhaust sample. Use the same units and modal calculations as for your other results to report a single weighted value for CO2; round CO2 to the nearest 1 g/kW-hr.
(2) Each analyzer range that may be used during a test mode must have the zero and span responses recorded prior to the execution of the test. Only the zero and span for the range(s) used to measure the emissions during the test are required to be recorded after the completion of the test.
(3) It is permissible to change filter elements between test modes.
(4) A leak check is permitted between test segments.
(5) A hangup check is permitted between test segments.
(6) If, during the emission measurement portion of a test segment, the value of the gauges downstream of the NDIR analyzer(s) G3 or G4 (see Figure 1 in appendix B to subpart D) differs by more than ±0.5 kPa from the pretest value, the test segment is void.