[Code of Federal Regulations]
[Title 40, Volume 30]
[Revised as of July 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR1051.505]

[Page 627-628]
 
                   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) Measure emissions by testing the engine on a dynamometer with 
the steady-state duty cycle described in the following Table:

[[Page 628]]



                          Table 1 of Sec. 1051.505--5-Mode Duty Cycle for Snowmobiles
----------------------------------------------------------------------------------------------------------------
                                                                      Torque
                                                   Engine speed     (percent of
                                                    (percent of    maximum test    Minimum time      Weighting
                                                   maximum test      torque at        in mode         factors
                                                      speed)       maximum test      (minutes)
                                                                      speed)
----------------------------------------------------------------------------------------------------------------
Mode number:
    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...........................................            Idle               0             3.0            0.05
----------------------------------------------------------------------------------------------------------------

    (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 the peak torque value at 
maximum test speed.
    (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 (g) of this section.
    (e) See part 1065 of this chapter 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 Sec. 1065.10(c)(1) of this chapter. You must get 
our approval before you begin the emission testing. For example, the 
following approach would be appropriate to show that such testing 
complies with Sec. 1065.10(c)(1) of this chapter:
    (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 (g)(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 
of the corresponding modal temperature calculated in (g)(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.

[[Page 629]]