Technical Specification for Verification and Inspection of Vehicle Exhaust Emissions Analyzers

CNMV 99 Page 1, Totally 10 Pages

/ Technical Specification for Verification and Inspection of Vehicle Exhaust Emissions Analyzers / S/N / CNMV 99
Rev. / 1
1.This technical specification is enacted pursuant to Paragraph 2, Articles 14 and 16 of the Weights and Measures Act.
2. The revision, date of promulgations, document No, date of enforcement and content of the amendment are listed as follows:
Rev. / Date of Promulgation / Document No.
(Ching-Piao-Szu-Tsu ) / Date of Enforcement / Content of Amendment
1 / 21.05.2003 / No.09240004850 / 01.07.2003
3. This specification is formulated with reference to the following international specifications:
OIML R99 Instruments for measuring vehicle exhaust emissions (1998)
Date of Promulgation
21.05.2003 / Bureau of Standards, Metrology and Inspection, Ministry of Economic Affairs / Date of Enforcement
01.07.2003

Scope: The standard is applicable to analyzers for measuring exhaust emissions of in-use

motor vehicles with spark ignition engines.

2.Structure:

2.1Vehicle exhaust gas analyzers (hereinafter referred to as the “analyzer(s)”) shall have a permanent and easily readable labels giving the following information:

(1)Manufacturer’s corporate name/trade mark;

(2)Year of manufacture;

(3)Class (0, Ⅰ and Ⅱ);

(4)Serial number of the analyzer and of the measuring transducer;

(5)Calibration flow rate, minimum and nominal sampling flow rate (SLPM);

(6)Nominal mains voltage, frequency and power required;

(7)Gas components and respective maximum measured value;

The label information defined above shall be correct, obvious and hard to be erased.

2.2 The value of the propane/hexane equivalency factor for each analyzer, and the warm-up time for the instruments shall be marked permanently on the front panel of the analyzer or shall be displayable on the indicating device.

2.3 For instruments with software-controlled metrological function, the identification of the legally relevant software shall be marked permanently on the front panel of the instrument or shall be displayable on the indicating device.

2.4The measured result of the gas components shall be unambiguously expressed as “% vol. CO”, “% vol. CO2” and “ppm vol. HC”. HC: the concentration of hydrocarbons shall be expressed as n-hexane equivant via conversion factor.

2.5The gas handling system shall contain a filter unit with replaceable element capable of removing particles, it shall be possible to observe the degree of a filter’s contamination without its removal, and it shall also be possible to replace, when necessary, this filter easily without special tools.

2.6The gas handling system shall contain a water separator that prevents water condensation from forming in the measuring transducer.

2.7In addition to the gas sampling port, instruments shall have a calibration port. Instruments with an HC channel shall have a port for drawing in ambient air or other gas without hydrocarbons, to provide a reference for zero-setting of the measuring instruments. If used, ambient air shall pass through a charcoal filter or equivalent system.

2.8The pump conveying the exhaust gas shall be mounted so that its vibrations do not affect the measurements; however, it shall not be possible to make a measurement when the pump is switched off.

2.9The minimum measuring range that may be subdivided shall be as given in Table 1.

Table 1

Measurand
Class / CO(1) / CO(2) / CO2 / HC(1) / HC(2)
0, Ⅰ / 0% vol.
to
5% vol. / 0% vol.
to
8% vol. / 0% vol.
to
16% vol. / 0 ppm vol.
to
2000 ppm vol. / 0 ppm vol.
to
14000 ppm
vol.
Ⅱ / 0% vol.
to
7% vol. / 0% vol.
to
8% vol. / 0% vol.
to
16% vol. / 0 ppm vol.
to
2000 ppm vol. / 0 ppm vol.
to
14000 ppm
vol.

CO(1) and HC(1): the standard concentration of analyzer is suitable for car.

CO(2) and HC(2): the standard concentration of analyzer is suitable for motorcycle.

2.10The minimum scale intervals of indication is specified below:

2.10.1 For analog instruments, the minimum scale intervals for CO, CO2 and HC shall be comply with the requirements given in Table 2.

Table 2

Measurand
Class / CO / CO2 / HC(1)
0, Ⅰ / 0.1% vol. / 0.1% vol. / 10 ppm vol.
Ⅱ / 0.2% vol. / 0.2% vol. / 20 ppm vol.

The minimum scale spacing shall be 1.25 mm. The thickness of the needle shall not be greater than one quarter of the scale spacing. The needle shall overlap at least; one third of the shortest mark and shall be clearly visible. The graduation shall be designated with figures at least 5 mm high and designed in such away as to prevent misinterpretation..

2.10.2 The digital figures for the instruments shall be at least 5 mm high. The least significant figure of the display shall provide a resolution equal to or one order of magnitude higher than the values given in Table 3:

Table 3

Measurand
Class / CO / CO2 / HC(1) / HC(2)
0, Ⅰ / 0.01% vol. / 0.1% vol. / 1 ppm vol. / 10 ppm vol.
Ⅱ / 0.05% vol. / 0.1% vol. / 5 ppm vol. / 20 ppm vol.

HC(1): the standard concentration of analyzer is suitable for car.

HC(2): the standard concentration of analyzer is suitable for motorcycle.

2.11A battery-operated instrument shall either continue to function correctly or not indicate any value whenever the voltage is below the manufacture’s specified value.

2.12The instruments shall be equipped with the gas handling system for sampling, the function for the indication of the flush and block.

2.13The analyzer shall be equipped with an interface device for the serial digital RS-232 or the analog signal to read the raw test data of the sampling and calibrating.

3.Verification, inspection and maximum permissible errors

3.1The requirements of verification and inspection equipment are as follows:

(1)Standard gas: it should be traceable to national or international standard, except hydrocarbons (the relative expanded uncertainty U is shown below), the other relative expanded uncertainties shall be 1% or less.

HC(1):where HC(1) is below 1000 ppm, U is 2% or less; where HC(1) is between 1000 ppm to 2000 ppm, U is 1% or less.

HC(2):where HC(2) is below 7000 ppm, U is 2% or less; U is 1% or less, where HC(1) is 7000 to 14000 ppm.

U is 2% or less, where the standard gas is used for verification and inspection of the in-use instruments.

U: means the relative expanded uncertainty under 95% reliable levels and the expanding coefficient is 2.

(2)Zero gas: High pure nitrogen with THC＜0.5ppm, CO＜1ppm, CO2＜1ppm and H2O ＜5ppm.

(3)Stopwatch: facility shall measure over 8 hours and the minimum resolution of indication is 0.1 sec or less.

(4)Thermometer: facility shall measure 5 to 40 oC upward, the minimum resolution of indication is 0.5 oC or less. The uncertainty shall be 1 oC or less.

(5)Pressure meter: facility shall measure 80-106 kPa upward, the minimum resolution of indicatio is 2 kPa or less. The uncertainty shall be 5 kPa or less.

(6)Flow controller: facility shall measure 0-10 SLPM, the minimum resolution of indicatio is 10SCCM or less, and the uncertainty shall be 300 sccm or less.

3.2The verification and inspection items shall include the following tests:

(1)Appearance, structure and performance.

(2)Warm-up test (in use instruments need not perform this item).

(3)Response time test.

(4)Accuracy and reproducibility test.

(5)Leakage test.

(6)HC residue test (in use instruments need not perform this item).

(7)Low flow test.

3.3The conduct of test items defined above shall conform the following condition:

3.3.1The tests shall be performed using the standard gas given in Table 4.

Table 4

Gas component, concentration and serial number
Measurand / No. 1 gas / No. 2 gas / No. 3 gas / No. 4 gas
CO(1) / 0.8% vol.10% / 1.6% vol. 10% / 3.2% vol.10% / 4% vol.10%
CO(2) / 3.2% vol.10% / 4.8% vol. 10% / 6.4% vol.10% / 8% vol.10%
CO2 / 5.6% vol.10% / 8.4% vol. 10% / 11.2% vol.10% / 14% vol.10%
HC(1) / 160 ppm vol. 15% / 320 ppm vol. 15% / 1280 ppm vol. 15% / 1600 ppm vol. 15%
HC(2) / 4800 ppm vol. 15% / 7200 ppm vol. 10% / 9600 ppm vol. 10% / 12000 ppm vol. 10%

3.3.2After the warm-up time, the instruments shall perform the test items immediately.

3.3.3The span gas shall use the No. 4 gas to perform the calibration.

3.3.4The verification and inspection tests performed in laboratory shall use the span gas with labeled calibration-flow to perform the calibrated adjustment from the calibration gas port of instruments. And the calibrated adjustment for the verification of the on site instruments is performed with on site span gas. After the calibrated adjustment, all of the verification test items are performed from gas sampling port with the standard gas No. 1, 2 and 3.

3.3.5After inputting test-gas for 20 sec, just start to get the acquisition of sampling data. At the same time take three continuous data to calculate the mean value as the record basis.

3.3.6While performing calibration and test through the gas sampling port and drawing-type calibration port, the flow rate of the sample and span gas shall be greater than the labeled flow on the instruments, so that the superfluous test-gas can flow out from the branch.

3.3.7capillary–type calibration inlet shall take off the tube from calibration port and connect to the standard gas system to do the verification and inspection test.

3.3.8The test through the sampling gas inlet means that the test gas must go through the gas handling system that contains the sampling probe and pre-filter unit.

3.4Warm-up test: immediately after either the instruments warm-up period has elapsed or an automatic warm-up lockout has been deactivated, perform a span adjustment within 1 minute; then at time intervals of 2 min, 5 min and 15 min after warm-up, perform a measurement with No. 3 gas.The difference between any of the four measured value and individual 3 test results shall not exceed the modulus of the maximum permissible error on initial verification.

3.5Response time test: A measurement shall be employed for instantly changing from the instrument flush of the zero gas to sampling the No. 1 gas through the probe at ambient pressure. For measuring CO, HC, instruments including the specified gas handling system shall indicate 90% of the final value within 10 sec or less after changing from a gas with zero content.

3.6Rated operation conditions

Main voltage: -15% to +10% of the nominal voltage, and 2% of nominal frequency.

Under the rated operation condition of instruments, the error of measuring instruments for the verification and inspection test shall perform the calibration adjustment at the zero and span with No. 4 gas first, then proceed three-cycle consecutive measurements with No. 1, 2, 3 gas concentration, and the three-time mean of the standard deviation for each measurand is the result of the reproducibility test. The difference between the three-time average and certificate value for each measurand is the error of measuring instruments for the result of the accuracy test.

3.7Maximum permissible errors on the verification

3.7.1The maximum permissible errors given in Table 5 shall apply for instruments on initial verification.

Table 5

Measurand
Class / CO(1) / CO(2) / CO2 / HC(1) / HC(2)
O / a+
b+ / 0.03% vol.
5% / 0.06% vol.
5% / 0.5% vol.
5% / 10 ppm vol.
5% / 70 ppm vol.
5%
Ⅰ / a+
b+ / 0.06% vol.
5% / 0.12% vol.
5% / 0.5% vol.
5% / 12 ppm vol.
5% / 84 ppm vol.
5%
Ⅱ / a+
b+ / 0.2% vol.
10% / 0.2% vol.
10% / 1% vol.
10% / 30 ppm vol.
10% / 210 ppm vol.
10%

+Absolute or relative, whichever is greater.

a+: The absolute error of measurement .

b+ : The relative error of measurement.3.7.2The maximum permissible errors given in Table 6 shall apply for instruments on subsequent verification.

Table 6

Measurand
Class / CO(1) / CO(2) / CO2 / HC(1) / HC(2)
O / a+
b+ / 0.04% vol.
8% / 0.08% vol.
8% / 0.5% vol.
8% / 16 ppm vol.
8% / 112 ppm vol.
8%
Ⅰ / a+
b+ / 0.08% vol.
8% / 0.16% vol.
8% / 0.5% vol.
8% / 19 ppm vol.
8% / 133 ppm vol.
8%
Ⅱ / a+
b+ / 0.2% vol.
10% / 0.2% vol.
10% / 1% vol.
10% / 30 ppm vol.
10% / 210 ppm vol.
10%

+Absolute or relative, whichever is greater.

a+: The absolute error of measurement .

b+ : The relative error of measurement.

3.8The maximum permissible errors on the inspection and verification are identical.

3.9The result of the accuracy test shall not be greater than the maximum permissible errors on verification, and the result of the reproducibility test for the No. 2 gas shall not be greater than one fourth of the maximum permissible errors on verification.

3.10Leakage test: an adjustable leakage device shall be introduced artificially into the gas handling system near the sampling port, then adjust the leakage with zero gas for the No. 1 gas to proceed the dilution measurement, when the difference of the indication and certificate value is greater than the half of the maximum permissible errors, without disturbing the artificial leak, remove the calibration gas supplied at the probe, and conduct the leakage test procedure as described in the manufacture’s operating instructions to check whether the instruments equip with the function of the leakage test.

3.11The gas handling system shall be airtight to such an extent that the influence of dilution with ambient air on the measuring results shall not be more than half the modulus of the maximum permissible error on verification. Class 0 or class Ⅰ instruments shall not be able to make a measurement if leakage of the gas handling system is found by leakage test.

3.12HC residue test: immediately after the sampling at least 5 min with No. 4 gas, conduct an HC residue check as described by the manufacture’s operating instructions, and the instruments shall stop the residue test within 30 sec. and take the HC records. Repeat this operation three times, and then supply the No. 3 gas to check compliance with the maximum permissible error on verification of the accuracy test.

3.13The three-time HC residue values of the HC-residue-check test shall be less than twice of the absolute maximum permissible error of the class 0 measurand, and the following maximum permissible error on verification of the accuracy test shall not be more than half of the maximum permissible error of the test gas. The class 0 or class Ⅰ instruments shall not be able to make a measurement if the HC residue value exceeds too high.

3.14Low flow test: a measurement shall be performed with a No. 1 gas that is initially supplied to the gas handling system at a gas flow rate greater than the minimum required by the tested instrument. During the measurement, the gas flow rate shall be gradually reduced. When the difference of the indication and certificate value is greater than the half the modulus of the maximum permissible error on verification, the instrument shall indicate the low flow responds, and for class 0 or class Ⅰ instruments, when that limit is reached, the device shall prevent measurement.

3.15The term of validity of the verification for the instruments is one year from the first day of the next month since the date affixed with a verified conformity mark.

3.16New instruments and the other instruments that has changed sensors or software version in the term of validity of the verification shall perform a verification test in laboratory.

4.The verification compliance marks

4.1The place of verification compliance marks of the instruments shall be on the front and obvious, affixed a verification compliance tag on the instrument.

4.2After the instrument passed verification, a verification compliance certificate shall be issued.

Attached Table

Table 1: Verification Compliance Certificate

Bureau of Standards, Metrology and Inspection ○○○○○
Verification Compliance Certificate of Vehicle Exhaust Emissions Analyzer

Applicant:
Address:
Specification:
Brand:
Type No.:
Instrument No: Primer:

Sensor:

Category:
Class:
Verification Compliance Tag No.:
Date of Verification: yy/mm/dd
Date of Expiry: yy/mm/dd

Within the validity period, vehicle exhaust emissions analyzers should run checking tests periodically with traced and certified standard gas in order to apply the analyzer in legal tests continuously.
Date: yy/mm/dd.