Document ID: chunk:federal_register_of_legislation:F2021C01210:reg:90:p4
Version: federal_register_of_legislation:F2021C01210
Segment Type: reg
Provision Reference: reg 90 (pt 4/7)
Character Range: 76352–78994

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 for the de-speeded and de-rated engine to cover the range of speed and power allowed for in paragraph 6.3.4. of part I of this Regulation covering the modification of an engine type. In this case the steady state visible pollutants will also be measured with the engine rated at these other points, by the method described in annex 4 of this Regulation, to enable the free acceleration absorption coefficient to be corrected in accordance with paragraph 3 of this annex. These values shall be recorded in table 2 of annex 2 of this Regulation.
        The diagram below shows the six possible measuring points of the matrix and the range of power and speed governed by each point.

percent of maximum torque at rated speed  maximum percent of that speed

1 100 100
2 90 100
3 100 90
4 90 90
5 100 80
6 90 80

        Each measuring point governs the power and speed area to the left of and below that point and is the measuring point for any engine rated in that area. For example the measuring point at "A" which is for the 90 per cent full load line and 100 per cent rated speed applies to the rated power/speed area bounded by ABCD on the diagram.
        2.3  If the test is a bench test the engine shall be disconnected from the brake, the latter being replaced either by the rotating parts driven when no gear is engaged or by an inertia substantially equivalent to that of the said parts (see paragraph 7.3 of annex 1 to this Regulation).
        2.4  If the test is carried out on a vehicle the gear-change control shall be set in the neutral position and the drive between engine and gear-box engaged.
        2.5  With the engine idling, the accelerator control shall be operated quickly, but not violently, so as to obtain maximum delivery from the injection pump. This position shall be maintained until maximum engine speed is reached and the governor comes into action. As soon as this speed is reached the accelerator shall be released until the engine resumes its idling speed and the opacimeter reverts to the corresponding conditions.
        2.6  The operation described in paragraph 2.5 above shall be repeated not less than six times in order to clear the exhaust system and to allow for any necessary adjustment of the apparatus. The maximum opacity values read in each successive acceleration shall be noted until stabilized values are obtained.