detected during the 3-in. Hg mode of engine operation. (iii) Normal services (engine oil change and oil, fuel, and air filter servicing) will be allowed at manufacturer's recommended intervals. (iv) Crankcase emission control system may be serviced at 375-hour intervals or longer. (v) Adjust choke or idle settings only if there is a problem of stalling, or at permitted major tuneups. (b) Complete emission tests (see §§ 85.100-85.109) shall be run before and after any engine maintenance which can be expected to affect emissions. § 85.112 Durability testing and emission measurements. The engine dynamometer service accumulation schedule will consist of several operating conditions which give the same percentage of time at various manifold vacuums and the modes as specified in the emission test cycle. The average speed shall be between 1,650 and 1,700 r.p.m. with some operation at 3,200 r.p.m. or governed speed, whichever is lower. Maximum cycle time shall be 15 minutes. A cycle approved by the Secretary shall be used. (a) Emission data engines. Each engine will be operated a minimum of 125 hours on an engine dynamometer according to an approved cycle with all emission control systems installed and operating. The results of emission tests conducted at 125 hours shall be supplied with the application for certification to establish the low-use emission level of each engine. (b) Durability data engines. Each engine will be operated 1,500 hours on an engine dynamometer with all emission control systems installed and operating. Emission measurements, as prescribed, shall be made at least every 125 hours. § 85.113 Compliance with emission standards. (a) The emission standards in this part apply to the life-time emissions of equipped engines in public use. Prior to certification, life-time emissions can be obtained by projection of test data to life-time normal service. Normal service in an urban area for 100,000 miles is taken as the basis for "life-time emis sions." Operation on an engine dynamometer in the prescribed manner for 3,000 hours is taken to be equivalent to such service. (b) It is expected that emission control efficiency will change with accumulation of usage of the engine. It is assumed that emissions corresponding to 1,500 hours of dynamometer operation is the average emission of engines over their lifetime. (c) The basic procedure for determining compliance with emission standards of systems or devices, installed on or incorporated in engines, is as follows: (1) Emission deterioration factors will be determined from the emission results of the combined durability data engines for each basic emission control system. (i) All applicable results will be plotted as a function of dynamometer hours and the best fit straight lines will be drawn through these data points. (ii) Deterioration factors for each basic emission control system will be calculated as follows: factor= emissions interpolated to 1,500 hours emissions interpolated to 125 hours (2) The emission test results from each emission data engine shall be multiplied by the corresponding deterioration factor. (3) The emission values to compare with the standard will be the adjusted emissions of subparagraph (2) of this paragraph classified according to engine displacement and, within each engine displacement, weighted according to relative expected sales volume of engines as represented by the individual test vehicles. Subpart J-Test Procedures for Engine Exhaust Emissions (Diesel Engines for Use in Heavy Duty Vehicles) § 85.120 Introduction. (a) The following procedure will be used in the testing program under section 206 of the Act to determine the conformity of new motor vehicle engines with the standards for exhaust set forth in this part. (b) The test consists of a prescribed sequence of engine operating conditions on an engine dynamometer with continuous examination of the exhaust gases. The test is applicable equally to controlled engines equipped with means or devices for preventing, controlling, or eliminating smoke emissions and to uncontrolled engines. The test applies to all diesel engines for use in heavy duty vehicles. (c) The test is designed to determine the opacity of smoke in exhaust emissions during those engine operating conditions which tend to promote smoke from diesel-powered vehicles. (d) The test procedure begins with a warm engine which is then run through preloading and preconditioning operations. After an idling period, the engine is operated through the acceleration and lugging modes during which smoke emission measurements to compare with the standards are made. The engine is then returned to the idle condition and the acceleration and lugging modes are repeated. Three acceleration and three lugging modes constitute the full set of operating conditions for smoke emission measurement. § 85.121 Diesel fuel specifications. (a) The diesel fuels employed shall be clean and bright, with pour and cloud points adequate for operability. The fuels may contain nonmetallic additives as follows: cetane improver, metal deactivator, antioxidant, dehazer, antirust, pour depressant, dye, and dispersant. (b) Fuel meeting the following specifications, or substantially equivalent specifications approved by the Secretary, shall be used in exhaust emission testing. The grade of fuel recommended by the engine manufacturer, commercially designated as "Type 1-D" or "Type 2-D,” shall be used. starting with the dynamometer preloading determined and the engine preconditioned. (§ 85.127(c).) (1) Idle mode. The engine is caused to idle for 5 minutes at the manufacturer's recommended low idle speed. The controls shall be set to provide minimum load by turning the load switch to the "off" position or by adjusting the controls to the minimum load position. (2) Acceleration mode. (i) The engine speed shall be increased to 200±50 r.p.m. above the manufacturer's recommended low idle speed in 2 to 3 seconds. (ii) The engine shall be accelerated at full-throttle against the inertia of the engine and dynamometer such that the engine speed reaches 85 to 90 percent of rated speed in 5±1.5 seconds. (iii) When the engine reaches the speed required in subdivision (ii) of this subparagraph, the throttle shall be moved rapidly to the closed position and the preselected dynamometer load shall be applied. The engine speed shall be reduced to the speed of maximum torque or 60 percent of rated speed (whichever is higher), each within ±50 r.p.m. Smoke emissions during this transitional mode are not used in determining smoke emissions to compare with the standard. (iv) The throttle shall be moved immediately to the full-throttle position so that the engine accelerates to 95 to 100 percent of rated speed in 10±2 seconds. (3) Lugging mode. (i) Proceeding from the acceleration mode, the dynamometer controls and throttle shall be adjusted to permit the engine to develop maximum rated horsepower. Smoke emissions during this transitional mode are not used in determining smoke emissions to compare to the standard. (ii) Without changing the throttle position, the dynamometer controls shall be gradually adjusted to slow the engine to the speed of maximum torque or to 60 percent of rated speed, whichever is higher. This engine lugging operation shall be performed smoothly over a period of 35±5 seconds. The rate of slowing of the engine shall be linear, within ±100 r.p.m. (4) Engine unloading. After completion of the lugging mode in subparagraph (3) (ii) of this paragraph, take appropriate steps to return the dynamometer and engine to the idle condition described in subparagraph (1) of this paragraph. When this is accomplished, prepare to repeat the cycle. (b) Repeat the procedures described in paragraph (a) (1) through (4) of this section until the entire cycle has been run three times. This will complete the test and the equipment is shut down. § 85.123 Dynamometer and engine equipment. The following equipment shall be used for smoke emission testing of engines on engine dynamometers. (a) Engine dynamometer with adequate characteristics to perform the test cycle described in § 85.122. (b) Engine cooling system having sufficient capacity to maintain the engine at normal operating temperatures during conduct of the prescribed engine tests. (c) A noninsulated exhaust system extending 12±2 feet from the exhaust manifold of the engine and presenting an exhaust back pressure within ±0.2 inches Hg of the upper limit at maximum rated horsepower, as established by the engine manufacturer in his sales and service literature for vehicle application. A conventional automotive muffler of a size and type commonly used with the engine being tested shall be employed in the exhaust system during smoke emission testing. The terminal 2 feet of the exhaust pipe shall be of circular cross section and be free of elbows and bends. The end of the pipe shall be cut off squarely. The terminal 2 feet of the exhaust pipe shall have a diameter in accordance with the engine being tested, as specified below: Maximum rated horsepower Less than 101. 101-200 201-300 301 or more--- Exhaust pipe size 2" 3" 4" 5" (d) An engine air inlet system presenting an air inlet restriction within +1 inch of water of the upper limit for the engine operating condition which results in maximum air flow, as established by the engine manufacturer in his sales and service literature, for the engine being tested. § 85.124 Smoke measurement system. (a) Schematic drawing. The following figure (fig. 6) is a schematic drawing of the optical system of the light extinction meter. Figure 7 shows the meter with a means for adapting the optical unit to the engine exhaust system. the pipe at right angles to the axis of the plume. The light source is an incandescent lamp operated at a constant voltage of not less than 15 percent of the manufacturer's specified voltage. The lamp output is collimated to a beam with a diameter which does not exceed 0.4 exhaust pipe diameters. The angle of divergence of the collimated beam shall be within 4° included angle. A light detector, directly opposed to the light source, measures the amount of light blocked by the smoke in the exhaust. The detector sensitivity is restricted to the visual range and comparable to that of the human eye. A collimating tube with apertures equal to the beam diameter is attached to the detector. It restricts the viewing angle of the detector to within 16° included angle. An amplified signal corresponding to the amount of light blocked is recorded continuously on a remote recorder. An air curtain across the light source and detector window assemblies may be used to minimize deposition of smoke particles on those surfaces provided that it does not measurably affect the opacity of the plume. The meter consists of two units, an optical unit and a remote control unit. Light extinction meters employing substantially identical measurement principles and producing substantially equivalent results but which employ other electronic and optical techniques for zeroing, spanning, and calibration than those described, are deemed to be acceptable substitutes. (3) Recorder-a continuous recorder, with variable chart speed over a minimal range of 0.5 to 8.0 inches per minute (or equivalent) shall be used for continuously recording the transient conditions of exhaust gas opacity and engine r.p.m. The recorder scale for opacity shall be linear and calibrated to read from 0 to 100 percent opacity full scale. The opacity trace shall have a resolution within 1 percent opacity. The recorder scale for engine r.p.m. shall be linear and calibrated in units to facilitate chart reading. The r.p.m. trace shall have a resolution within 30 r.p.m. Any means other than a strip chart recorder may be used provided it produces a permanent visual record of the data which is of equal or better quality as that described above. (4) The recorder used with the smokemeter shall be capable of fullscale deflection in 0.5 second or less. The smokemeter-recorder combination may be damped so that signals with a frequency higher than 10 cycles per second are attenuated. A separate low-pass electronic filter with the following performance characteristics may be installed between the smokemeter and the recorder to achieve the high-frequency attenuation. (i) 3 decibel point-10 cycles per second. (ii) Insertion loss-zero ±0.5 decibels. (iii) Selectivity-12 decibels per octave above 10 cycles per second. (iv) Attenuation-27 decibels down at 40 cycles per second minimum. (c) Assembling equipment. (1) The optical unit of the smokemeter shall be mounted radially to the exhaust pipe so that the measurement will be made at right angles to the axis of the exhaust plume. The distance from the optical unit to the exhaust pipe outlet shall be 1.0 to 1.5 pipe diameters but never less than 4 inches. The full flow of the exhaust stream shall be contained within and be approximately centered about the light path of the unit in order for the test to be valid. (2) Power shall be supplied to the control unit of the smokemeter in time to allow at least 15 minutes for stabilization prior to its use. § 85.125 Information to be recorded. The following information shall be recorded with respect to each test: (a) Test number. (b) Date and time of day. |