ISO 8178-9:2012 pdf download – Reciprocating internal combustionengines—Exhaust emission measurement— Part 9: Test cycles and test procedures fortest bed measurement of exhaust gassmoke emissions from compressionignition engines operating under transient conditions
ISO 8178-9:2012 pdf download – Reciprocating internal combustionengines—Exhaust emission measurement— Part 9: Test cycles and test procedures fortest bed measurement of exhaust gassmoke emissions from compressionignition engines operating under transient conditions.
220.127.116.11 Light source
The light source shall conform to the requirements of 11.2 and 11.3
18.104.22.168 Neutral densIty fitters
Any neutral density filters used tot calibrating and checking opacimeters must be known to an accuracy of ± 1 % opacity and the filter’s nominal value must be checked for accuracy at least yearly using a reference traceable to a national or International Standard.
Neutral density filters are precision devices and can easily be damaged during use. Handhng should be minimized and, when required, should be done with care to avoid scratching r soiling of the filter.
The Calibration of all measuring instruments shall be traceable to International Standards (or national standards if no International Standards exist) and comply with the requirements given in Table 3.
8 Calibration of the opacimeter
The opacimeter shall be calibrated as often as necessary in order to fulfil the accuracy requirements of this part of ISO 8178 The calibration method that shall be used Is described in 8.2.
8.2 Calibration procedure
8.2.1 WarmIng-up time
The opacimeler shall be warmed up and stabilized in accordance with the manufacturers recommendations. If the opacimeter is equipped with a purge air system to prevent sootang of the instrument optics, this system should also be activated and adjusted in accordance with the manufacturer’s reconirnendations.
82.2 Establishment of the linearity response
With the opacirneter in the opacity readout mode, and with no blockage of the opacimeter light beam, the readout shall be adjusted toO % ± 0.5 % opacity.
With the opacimeter in the opacity readout mode, and all light prevented from reaching the receiver, the readout shall be adjusted to 100 $ ± 0,5 % opacity.
The linearity of the opacimeler. when used in the opacity mode, shall be checked periodically en accordance with the manufacturer’s recommendations. A neutral density filter between 30% and 60% opacity which meets the requirements of 22.214.171.124 shall be Introduced to the opacimeler and the value recorded. The Instrument readout must not differ by more than ± 2 % opacity from the nominal value of the neutral density filter. Any nonlinearity exceeding the above value shall be corrected prior to the test.
9 Test run
9.1 InstallatIon of the measuring equipment
The opacimeter and sample probes, if applicable, shall be installed after the muffler or any after-treatment device, it fitted, according to the installation procedures specified by the instrument manufacturer. Additionally. the requirements of Clause 10 of ISO 11614:1999 shall be observed, where appropriate.
9.2 Checking of the opacimeter
Prior to any zero and full-scale checks, the opacimeter shal be warmed up and stabilized in accordance with the instrument manufacturers recommendations. If the opacimeter is equipped with a purge air system to prevent sooting of the meter optics, this system shall also be activated and adjusted in accordance with the manufacturers recommendations.
The zero and full-scale checks shall be made in the opacity readout mode, since the opacity scale offers two truly definab4e calibration points, namely 0 % opacity and 100 % opacity. The light absorption coefficient is then correctly calculated based upon the measured opacity and LA, as submitted by the opacimeter manufacturer, when the instrument is returned to the k readout mode for testing.
With no blockage of the opaci meter light beam. the readout shall be adjusted to 0 % ± 1 % opacity. With the hght being prevented from reaching the receiver, the readout shall be adjusted to 100 % ± I % opacity.
9.3 Test cycle
The engine shall be run on the test cycle as described in Annexes A, B. E and F, taking into account the considerations noted in Annex C.
9.4 DetermInation of eftective optical path length (LA)
Portions of the light source to receiver path length which are not smoke obscured do not contribute to the effective optical path length. lithe smokemeter light beam is located sufficiently close to the exhaust outlet (within 0,07 m). the cross section of the smoke plume as it passes by the smokemeter is essentially the same as the tadpipe outlet along the liie of orientation of the smokemeter light beani In general. this distance should be determined by direct measurement of the tailpipe outlet. To achieve corrected smoke results wt’iich are accurate within ± 2 % opacity, determination of LA shall be made within ± 6 %. (The largest error in opacity occurs at an opacity of approxImately 60 %, at lower and higher values of opacity, less accurate determination of LA can be tolerated.) For the smallest standard effective optical path length (0.038 m), ± 6 % equates to an accuracy of 0.002 m.