[Code of Federal Regulations] [Title 40, Volume 31] [Revised as of July 1, 2007] From the U.S. Government Printing Office via GPO Access [CITE: 40CFR1051.505] [Page 647-649] TITLE 40--PROTECTION OF ENVIRONMENT CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PART 1051_CONTROL OF EMISSIONS FROM RECREATIONAL ENGINES AND VEHICLES--Table of Contents Subpart F_Test Procedures Sec. 1051.505 What special provisions apply for testing snowmobiles? Use the following special provisions for testing snowmobiles: (a) You may perform steady-state testing with either discrete-mode or ramped-modal cycles. You must use the type of testing you select in your application for certification for all testing you perform for that engine family. If we test your engines to confirm that they meet emission standards, we will do testing the same way. We may also perform other testing as allowed by the Clean Air Act. Measure steady-state emissions as follows: (1) For discrete-mode testing, sample emissions separately for each mode, then calculate an average emission [[Page 648]] level for the whole cycle using the weighting factors specified for each mode. In each mode, operate the engine for at least 5 minutes, then sample emissions for at least 1 minute. Calculate cycle statistics for the sequence of modes and compare with the specified values in 40 CFR 1065.514 to confirm that the test is valid. (2) For ramped-modal testing, start sampling at the beginning of the first mode and continue sampling until the end of the last mode. Calculate emissions and cycle statistics the same as for transient testing. (3) Measure emissions by testing the engine on a dynamometer with one or more of the following sets of duty cycles to determine whether it meets the steady-state emission standards in Sec. 1051.103: (i) The following duty cycle applies for discrete-mode testing: Table 1 of Sec. 1051.505--5-Mode Duty Cycle for Snowmobiles ---------------------------------------------------------------------------------------------------------------- Minimum time Mode No. Speed Torque in mode Weighting (percent) \1\ (percent) \2\ (minutes) factors ---------------------------------------------------------------------------------------------------------------- 1............................................... 100 100 3.0 0.12 2............................................... 85 51 3.0 0.27 3............................................... 75 33 3.0 0.25 4............................................... 65 19 3.0 0.31 5............................................... (\3\) 0 3.0 0.05 ---------------------------------------------------------------------------------------------------------------- \1\ Percent speed is percent of maximum test speed. \2\ Percent torque is percent of maximum test torque at maximum test speed. \3\ Idle. (ii) The following duty cycle applies for ramped-modal testing: Table 2 of Sec. 1051.505--Ramped-Modal Cycle for Testing Snowmobiles ---------------------------------------------------------------------------------------------------------------- RMC mode Time in mode Speed (percent) \1\ Torque (percent) \2,3\ ---------------------------------------------------------------------------------------------------------------- 1a Steady-state..................... 27 Warm Idle.............. 0 1b Transition....................... 20 Linear Transition...... Linear Transition. 2a Steady-state..................... 121 100.................... 100 2b Transition....................... 20 Linear Transition...... Linear Transition. 3a Steady-state..................... 347 65..................... 19 3b Transition....................... 20 Linear Transition...... Linear Transition. 4a Steady-state..................... 305 85..................... 51 4b Transition....................... 20 Linear Transition...... Linear Transition. 5a Steady-state..................... 272 5...................... 33 5b Transition....................... 20 Linear Transition...... Linear Transition. 6 Steady-state...................... 28 Warm Idle.............. 0 ---------------------------------------------------------------------------------------------------------------- \1\ Percent speed is percent of maximum test speed. \2\ Advance from one mode to the next within a 20-second transition phase. During the transition phase, command a linear progression from the torque setting of the current mode to the torque setting of the next mode. \3\ Percent torque is percent of maximum test torque at maximum test speed. (b) During idle mode, operate the engine with the following parameters: (1) Hold the speed within your specifications. (2) Keep the throttle at the idle-stop position. (3) Keep engine torque under 5 percent of maximum test torque. (c) For the full-load operating mode, operate the engine at wide- open throttle. (d) Ambient temperatures during testing must be between 20 [deg]C and 30 [deg]C (68 [deg]F and 86 [deg]F), or other representative test temperatures, as specified in paragraph (f) of this section. (e) See 40 CFR part 1065 for detailed specifications of tolerances and calculations. (f) You may test snowmobiles at ambient temperatures below 20 [deg]C or using intake air temperatures below 20 [deg]C if you show that such testing complies with 40 CFR 1065.10(c)(1). You must get [[Page 649]] our approval before you begin the emission testing. For example, the following approach would be appropriate to show that such testing complies with 40 CFR 1065.10(c)(1): (1) Using good engineering judgment, instrument a representative snowmobile built with a representative engine from the family being tested with an appropriate temperature measuring device located in the intake air plenum where fuel spitback is not likely to occur. (2) Choose a time and location with the following weather conditions: windspeed less than 10 knots, no falling precipitation, air temperature between -20 [deg]C and 0 [deg]C (-4 [deg]F and 32 [deg]F). (3) Operate the snowmobile until its engine reaches a steady operating temperature. (4) Operate the snowmobile on a level surface free of other vehicle traffic. Operate the snowmobile at each specified engine speed corresponding to each mode in the emissions test specific to the engine being tested. When readings are stable, record the temperature in the intake air plenum and the ambient temperature. Calculate the temperature difference between the air in the plenum and the ambient air for each mode. (5) Calculate the nominal intake air test temperature for each test mode as -10 [deg]C (14 [deg]F) plus the temperature difference for the corresponding mode determined in paragraph (f)(4) of this section. (6) Before the emissions test, select the appropriate carburetor jetting for -10 [deg]C (14 [deg]F) conditions according to the jet chart. For each mode, maintain the inlet air temperature within 5 [deg]C (9 [deg]F) of the corresponding modal temperature calculated in paragraph (f)(5) of this section. (7) Adjust other operating parameters to be consistent with operation at -10 [deg]C (14 [deg]F). For example, this may require that you modify the engine cooling system used in the laboratory to make its performance representative of cold-temperature operation. [67 FR 68347, Nov. 8, 2002, as amended at 70 FR 40500, July 13, 2005]