Section 1065.1127 - Test procedure for determining percent opacityThe test procedure described in this section applies for everything other than locomotives. The test consists of a sequence of engine operating points on an engine dynamometer to measure exhaust opacity during specific engine operating modes to represent in-use operation. Measure opacity using the following procedure:
(a) Use the equipment and procedures specified in this part 1065.(b) Calibrate the smokemeter as follows:(1) Calibrate using neutral density filters with approximately 10, 20, and 40 percent opacity. Confirm that the opacity values for each of these reference filters are NIST-traceable within 185 days of testing, or within 370 days of testing if you consistently protect the reference filters from light exposure between tests.(2) Before each test and optionally during engine idle modes, remove the smokemeter from the exhaust stream, if applicable, and calibrate as follows: (i)Zero. Adjust the smokemeter to give a zero response when there is no detectable smoke.(ii)Linearity. Insert each of the qualified reference filters in the light path perpendicular to the axis of the light beam and adjust the smokemeter to give a result within 1 percentage point of the named value for each reference filter.(c) Prepare the engine, dynamometer, and smokemeter for testing as follows: (1) Set up the engine to run in a configuration that represents in-use operation.(2) Determine the smokemeter's optical path length to the nearest mm.(3) If the smokemeter uses purge air or another method to prevent deposits on the light source and detector, adjust the system according to the system manufacturer's instructions and activate the system before starting the engine.(4) Program the dynamometer to operate in torque-control mode throughout testing. Determine the dynamometer load needed to meet the cycle requirements in paragraphs (d)(4)(ii) and (iv) of this section.(5) You may program the dynamometer to apply motoring assist with negative flywheel torque, but only during the first 0.5 seconds of the acceleration events in paragraphs (d)(4)(i) and (ii) of this section. Negative flywheel torque may not exceed 13.6 N·m.(d) Operate the engine and dynamometer over repeated test runs of the duty cycle illustrated in Figure 1 of this appendix. As noted in the figure, the test run includes an acceleration mode from points A through F in the figure, followed by a lugging mode from points I to J. Detailed specifications for testing apply as follows: (1) Continuously record opacity, engine speed, engine torque, and operator demand over the course of the entire test at 10 Hz; however, you may interrupt measurements to recalibrate during each idle mode.(2) Precondition the engine by operating it for 10 minutes at maximum mapped power.(3) Operate the engine for (5.0 to 5.5) minutes at warm idle speed, 'nidle, with load set to Curb Idle Transmission Torque.(4) Operate the engine and dynamometer as follows during the acceleration mode: (i)First acceleration event-AB. Partially increase and hold operator demand to stabilize engine speed briefly at (200 ±50) r/min above 'nidle. The start of this acceleration is the start of the test (t = 0 s).(ii)Second acceleration event-CD. As soon as measured engine speed is within the range specified in paragraph (d)(4)(i) of this section, but not more than 3 seconds after the start of the test, rapidly set and hold operator demand at maximum. Operate the dynamometer using a preselected load to accelerate engine speed to 85 percent of maximum test speed, 'ntest, in (5 ±1.5) seconds. The engine speed throughout the acceleration must be within ±100 r/min of a target represented by a linear transition between the low and high engine speed targets.(iii)Transition-DEF. As soon as measured engine speed reaches 85 percent of 'ntest, rapidly set and hold operator demand at minimum and simultaneously apply a load to decelerate to intermediate speed in (0.5 to 3.5) seconds. Use the same load identified for the acceleration event in paragraph (d)(4)(iv) of this section.(iv)Third acceleration event-FGH. Rapidly set and hold operator demand at maximum when the engine is within ±50 r/min of intermediate speed. Operate the dynamometer using a preselected load to accelerate engine speed to at least 95 percent of 'ntest in (10 ±2) seconds.(5) Operate the engine and dynamometer as follows during the lugging mode: (i)Transition-HI. When the engine reaches 95 percent of 'ntest, keep operator demand at maximum and immediately set dynamometer load to control the engine at maximum mapped power. Continue the transition segment for (50 to 60) seconds. For at least the last 10 seconds of the transition segment, hold engine speed within ±50 r/min of 'ntest and power at or above 95 percent of maximum mapped power. Conclude the transition by increasing dynamometer load to reduce engine speed as specified in paragraph (d)(4)(iii) of this section, keeping operator demand at maximum.(ii)Lugging-IJ. Apply dynamometer loading as needed to decrease engine speed from 50 r/min below fntest to intermediate speed in (35 ±5) seconds. The engine speed must remain within ±100 r/min of a target represented by a linear transition between the low and high engine speed targets.(6) Return the dynamometer and engine controls to the idle position described in paragraph (d)(3) of this section within 60 seconds of completing the lugging mode.(7) Repeat the procedures in paragraphs (d)(3) through (6) of this section as needed to complete three valid test runs. If you fail to meet the specifications during a test run, continue to follow the specified duty cycle before starting the next test run.(8) Shut down the engine or remove the smokemeter from the exhaust stream to verify zero and linearity. Void the test if the smokemeter reports more than 2 percent opacity for the zero verification, or if the smokemeter's error for any of the linearity checks specified in paragraph (b)(2) of this section is more than 2 percent.(e) Analyze and validate the test data as follows:(1) Divide each test run into test segments. Each successive test segment starts when the preceding segment ends. Identify the test segments based on the following criteria:(i) The idle mode specified in paragraph (d)(3) of this section for the first test run starts immediately after engine preconditioning is complete. The idle mode for later test runs must start within 60 seconds after the end of the previous test run as specified in paragraph (d)(6) of this section. The idle mode ends when operator demand increases for the first acceleration event (Points A and B).(ii) The first acceleration event in paragraph (d)(4)(i) of this section ends when operator demand is set to maximum for the second acceleration event (Point C).(iii) The second acceleration event in paragraph (d)(4)(ii) of this section ends when the engine reaches 85 percent of maximum test speed, 'ntest, (Point D) and operator demand is set to minimum (Point E).(iv) The transition period in paragraph (d)(4)(iii) of this section ends when operator demand is set to maximum (Point F).(v) The third acceleration event in paragraph (d)(4)(iv) of this section ends when engine speed reaches 95 percent of 'ntest (Point H).(vi) The transition period in paragraph (d)(5)(i) of this section ends when engine speed first decreases to a point more than 50 r/min below 'ntest (Point I).(vii) The lugging mode in paragraph (d)(5)(ii) of this section ends when the engine reaches intermediate speed (Point J).(2) Convert measured instantaneous values to standard opacity values, Kstd, based on the appropriate optical path length specified in Table 1 of § 1065.1125 using the following equation: View Image
Where:
Kstd = standard instantaneous percent opacity.
Kmeas = measured instantaneous percent opacity.
lstd = standard optical path length corresponding with engine power, in millimeters.
lmeas = the smokemeter's optical path length, in millimeters.
Example for an engine [LESS THAN] 40 kW:
= 14.1%
= 38 mm
= 41 mm
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(3) Select opacity results from corrected measurements collected across test segments as follows:(i) Divide measurements from acceleration and lugging modes into half-second intervals. Determine average opacity values during each half-second interval.(ii) Identify the 15 highest half-second values during the acceleration mode of each test run.(iii) Identify the five highest half-second values during the lugging mode of each test run.(iv) Identify the three overall highest values from paragraphs (e)(3)(ii) and (iii) of this section for each test run.(f) Determine percent opacity as follows:(1)Acceleration. Determine the percent opacity for the acceleration mode by calculating the average of the 45 readings from paragraph (e)(3)(ii) of this section.(2)Lugging. Determine the percent opacity for the lugging mode by calculating the average of the 15 readings from paragraph (e)(3)(iii) of this section.(3)Peak. Determine the percent opacity for the peaks in either acceleration or lugging mode by calculating the average of the 9 readings from paragraph (e)(3)(iv) of this section.(g) Submit the following information in addition to what is required by § 1065.695 : (1) Exhaust pipe diameter(s).(2) Measured maximum exhaust system backpressure over the entire test.(3) Most recent date for establishing that each of the reference filters from paragraph (b) of this section are NIST-traceable.(4) Measured smokemeter zero and linearity values after testing.(5) 10 Hz data from all valid test runs.(h) The following figure illustrates the dynamometer controls and engine speeds for exhaust opacity testing: Figure 1 to paragraph (h) of § 1065.1127 -Schemati of Smoke Opacity Duty Cycle
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