Document ID: chunk:federal_register_of_legislation:F2021C01210:reg:90:p3
Version: federal_register_of_legislation:F2021C01210
Segment Type: reg
Provision Reference: reg 90 (pt 3/7)
Character Range: 73746–76613

10 to this Regulation which corresponds to the following  provisions:
        3.3.1.1 Naturally-aspirated and mechanically-supercharged engines:
  fa =
        3.3.1.2 Turbo-supercharged engine with or without cooling of inlet air:
fa =
        3.3.2 For a test to be recognized as valid, the parameter fa shall be such that 0. 98 < fa <  1.02.

        3.4  Sampling and measuring apparatus
        The light-absorption coefficient of the exhaust gases shall be measured with an opacimeter satisfying the conditions laid down in annex 8 and installed in conformity with annex 9 to this Regulation.

---------------
        l/  The test may be carried out in air-conditioned test rooms where the atmospheric conditions may be controlled.

4.  EVALUATION OF THE ABSORPTION COEFFICIENT
        4.1  For each of the engine speeds at which the absorption coefficient is measured pursuant to paragraph 2.2 above, the nominal gas flow shall be calculated by means of the following formulae:

                             for two-stroke engines  G = V.n/60
                             for four-stroke engines G = V.n/120
in which:
G = nominal gas flow, in litres per second (l/s)
V = cylinder capacity of the engine, in litres (1)
n = engine speed, in revolutions per minute (min -1)

        4.2 Where the value of the nominal flow is not one of those given in that table in annex 7 to this Regulation, the limit value applicable shall be obtained by interpolation on the principle of proportional parts.
        Annex 5
TEST UNDER FREE ACCELERATION

  1.   TEST CONDITIONS
        1.1  The test shall be carried out on an engine installed on a test bench or on a vehicle.
        1.1.1 If the engine test is a bench test it shall be carried out as soon as possible after the test for measurement of opacity under full load at steady speed. In particular, the cooling water and the oil shall be at the normal temperatures stated by the manufacturer.
        1.1.2 If the test is carried out on a stationary vehicle the engine shall first be brought to normal operating conditions during a road run or on a dynamic test. The test shall be carried out as soon as possible after completion of this warming up period.
        1.2  The combustion chamber shall not have been cooled or fouled by a prolonged period of idling preceding the test.
        1.3  The test conditions prescribed in annex 4, paragraphs 3.1, 3.2 and 3.3, shall apply.
        1.4  The conditions prescribed in annex 4, paragraph 3.4, with regard to the sampling and measuring apparatus shall apply.

  2.   TEST METHODS
        2.1  The free acceleration visible pollutants shall be measured with the engine in the maximum rated speed and maximum power condition.
        2.2  At the request of the manufacturer, measurements shall also be made over a matrix of up to five other power/speed combinations