Directive 2005/55/EC of the European Parliament and of the Council (repealed)Show full title

[F1 4. DETERMINATION OF THE PARTICULATES U.K.

The determination of the particulates requires a dilution system. Dilution may be accomplished by a partial flow dilution system or a full flow double dilution system. The flow capacity of the dilution system shall be large enough to completely eliminate water condensation in the dilution and sampling systems. The temperature of the diluted exhaust gas shall be below 325 K (52 °C) (1) immediately upstream of the filter holders. Humidity control of the dilution air before entering the dilution system is permitted, and especially dehumidifying is useful if dilution air humidity is high. The temperature of the dilution air shall be higher than 288 K (15 °C) in close proximity to the entrance into the dilution tunnel.

The partial flow dilution system has to be designed to extract a proportional raw exhaust sample from the engine exhaust stream, thus responding to excursions in the exhaust stream flow rate, and introduce dilution air to this sample to achieve a temperature below 325 K (52 °C) at the test filter. For this it is essential that the dilution ratio or the sampling ratio r _dil or r _s be determined such that the accuracy limits of section 3.2.1 of Appendix 5 to this Annex are fulfilled. Different extraction methods can be applied, whereby the type of extraction used dictates to a significant degree the sampling hardware and procedures to be used (section 2.2 of Annex V).

In general, the particulate sampling probe shall be installed in close proximity to the gaseous emissions sampling probe, but sufficiently distant as to not cause interference. Therefore, the installation provisions of section 3.4.1 also apply to particulate sampling. The sampling line shall conform to the requirements of section 2 of Annex V.

In the case of a multi-cylinder engine with a branched exhaust manifold, the inlet of the probe shall be located sufficiently far downstream so as to ensure that the sample is representative of the average exhaust emissions from all cylinders. In multi-cylinder engines having distinct groups of manifolds, such as in a ‘ Vee ’ engine configuration, it is recommended to combine the manifolds upstream of the sampling probe. If this is not practical, it is permissible to acquire a sample from the group with the highest particulate emission. Other methods which have been shown to correlate with the above methods may be used. For exhaust emission calculation the total exhaust mass flow shall be used.

To determine the mass of the particulates, a particulate sampling system, particulate sampling filters, a microgram balance, and a temperature and humidity controlled weighing chamber, are required.

For particulate sampling, the single filter method shall be applied which uses one filter (see section 4.1.3) for the whole test cycle. For the ESC, considerable attention must be paid to sampling times and flows during the sampling phase of the test.

4.1. Particulate sampling filters U.K.

The diluted exhaust shall be sampled by a filter that meets the requirements of sections 4.1.1 and 4.1.2 during the test sequence.

4.1.1. Filter specification U.K.

Fluorocarbon coated glass fiber filters are required. All filter types shall have a 0,3 μm DOP (di-octylphthalate) collection efficiency of at least 99 % at a gas face velocity between 35 and 100 cm/s.

4.1.2. Filter size U.K.

Particulate filters with a diameter of 47 mm or 70 mm are recommended. Larger diameter filters are acceptable (section 4.1.4), but smaller diameter filters are not permitted.

4.1.3. Filter face velocity U.K.

A gas face velocity through the filter of 35 to 100 cm/s shall be achieved. The pressure drop increase between the beginning and the end of the test shall be no more than 25 kPa.

4.1.4. Filter loading U.K.

The required minimum filter loadings for the most common filter sizes are shown in table 10. For larger filter sizes, the minimum filter loading shall be 0,065 mg/ 1 000  mm ² filter area.

Table 10

Minimum Filter Loadings

Filter Diameter (mm)	Minimum loading (mg)
47	0,11
70	0,25
90	0,41
110	0,62

If, based on previous testing, the required minimum filter loading is unlikely to be reached on a test cycle after optimisation of flow rates and dilution ratio, a lower filter loading may be acceptable, with the agreement of the parties involved, if it can be shown to meet the accuracy requirements of section 4.2, e.g. with a 0,1 μg balance.

4.1.5. Filter holder U.K.

For the emissions test, the filters shall be placed in a filter holder assembly meeting the requirements of section 2.2 of Annex V. The filter holder assembly shall be of a design that provides an even flow distribution across the filter stain area. Quick acting valves shall be located either upstream or downstream of the filter holder. An inertial pre-classifier with a 50 % cut point between 2,5 μm and 10 μm may be installed immediately upstream of the filter holder. The use of the pre-classifier is strongly recommended if an open tube sampling probe facing upstream into the exhaust flow is used.

4.2. Weighing chamber and analytical balance specifications U.K.

4.2.1. Weighing chamber conditions U.K.

The temperature of the chamber (or room) in which the particulate filters are conditioned and weighed shall be maintained to within 295 K ±3 K (22 °C ±3 °C) during all filter conditioning and weighing. The humidity shall be maintained to a dewpoint of 282,5 K ±3 K (9,5 °C ±3 °C) and a relative humidity of 45 % ±8 %.

4.2.2. Reference filter weighing U.K.

The chamber (or room) environment shall be free of any ambient contaminants (such as dust) that would settle on the particulate filters during their stabilisation. Disturbances to weighing room specifications as outlined in section 4.2.1 will be allowed if the duration of the disturbances does not exceed 30 minutes. The weighing room should meet the required specifications prior to personal entrance into the weighing room. At least two unused reference filters shall be weighed within 4 hours of, but preferably at the same time as the sample filter weightings. They shall be the same size and material as the sample filters.

If the average weight of the reference filters changes between sample filter weightings by more than 10 μg, then all sample filters shall be discarded and the emissions test repeated.

If the weighing room stability criteria outlined in section 4.2.1 is not met, but the reference filter weightings meet the above criteria, the engine manufacturer has the option of accepting the sample filter weights or voiding the tests, fixing the weighing room control system and re-running the test.

4.2.3. Analytical balance U.K.

The analytical balance used to determine the filter weight shall have a precision (standard deviation) of at least 2 μg and a resolution of at least 1 μg (1 digit = 1 μg) specified by the balance manufacturer.

4.2.4. Elimination of static electricity effects U.K.

To eliminate the effects of static electricity, the filters shall be neutralized prior to weighing, e.g. by a Polonium neutralizer, a Faraday cage or a device of similar effect.

4.2.5. Specifications for flow measurement U.K.

4.2.5.1. General requirements U.K.

Absolute accuracies of flow meter or flow measurement instrumentation shall be as specified in section 2.2.

4.2.5.2. Special provisions for partial flow dilution systems U.K.

For partial flow dilution systems, the accuracy of the sample flow q _mp is of special concern, if not measured directly, but determined by differential flow measurement:

q _mp = q _mdew – q _mdw

In this case an accuracy of ±2 % for q _mdew and q _mdw is not sufficient to guarantee acceptable accuracies of q _mp . If the gas flow is determined by differential flow measurement, the maximum error of the difference shall be such that the accuracy of q _mp is within ±5 % when the dilution ratio is less than 15. It can be calculated by taking root-mean-square of the errors of each instrument.

Acceptable accuracies of q _mp can be obtained by either of the following methods:

The absolute accuracies of q _mdew and q _mdw are ±0,2 % which guarantees an accuracy of q _mp of ≤ 5 % at a dilution ratio of 15. However, greater errors will occur at higher dilution ratios;

calibration of q _mdw relative to q _mdew is carried out such that the same accuracies for q _mp as in a) are obtained. For the details of such a calibration see section 3.2.1 of Appendix 5 to Annex III;

the accuracy of q _mp is determined indirectly from the accuracy of the dilution ratio as determined by a tracer gas, e.g. CO ₂ . Again, accuracies equivalent to method a) for q _mp are required;

the absolute accuracy of q _mdew and q _mdw is within ±2 % of full scale, the maximum error of the difference between q _mdew and q _mdw is within 0,2 %, and the linearity error is within ±0,2 % of the highest q _mdew observed during the test.]

Textual Amendments

F1 Substituted by Commission Directive 2005/78/EC of 14 November 2005 implementing Directive 2005/55/EC of the European Parliament and of the Council on the approximation of the laws of the Member States relating to the measures to be taken against the emission of gaseous and particulate pollutants from compression-ignition engines for use in vehicles, and the emission of gaseous pollutants from positive ignition engines fuelled with natural gas or liquefied petroleum gas for use in vehicles and amending Annexes I, II, III, IV and VI thereto (Text with EEA relevance).

(1)

[F1 The Commission shall review the temperature upstream of the filter holder, 325 K (52 °C), and, if necessary propose an alternative temperature to be applicable for type-approval of new types from 1 October 2008 .]

Textual Amendments

F1 Substituted by Commission Directive 2005/78/EC of 14 November 2005 implementing Directive 2005/55/EC of the European Parliament and of the Council on the approximation of the laws of the Member States relating to the measures to be taken against the emission of gaseous and particulate pollutants from compression-ignition engines for use in vehicles, and the emission of gaseous pollutants from positive ignition engines fuelled with natural gas or liquefied petroleum gas for use in vehicles and amending Annexes I, II, III, IV and VI thereto (Text with EEA relevance).