GB/T 18377-2001Requirements and measurement methods of catalytic converters for petrol vehicles (English PDF)

3.1 catalytic converter

A device which uses catalysts to reduce hydrocarbon (HC), carbon monoxide (CO)

and nitric oxide (NOx) in automotive exhaust.

3.2 original equipment catalytic converter

4.1 For all test items which are carried out on the road or in test site, the test

conditions and vehicle preparation etc. shall comply with the general provisions of

GB/T 123534.

4.2 For all test items which are carried out inside test room, the test conditions etc.

shall comply with the general provisions of GB 14761 or GB 14762.

4.3 The vehicle for the evaluation test for the replacement catalytic converter shall

be driven for 3 000 km at least. The vehicle emission control system shall be free from

any defect; any original equipment part related to emission control shall be repaired or

replaced in case of excessive wear or malfunction. Before emission test, the vehicle

shall be adjusted correctly according to the technical specifications of the manufacturer.

4.4 The engine for the accelerated ageing test of the catalytic converter shall be

repaired and maintained correctly to ensure all properties comply with the technical

specifications of the manufacturer, especially that during the accelerated ageing test

of the catalytic converter, the excess air coefficient of the engine under steady working

conditions shall be controlled within the range of 1 ± 0.02.

5.1 General requirements

5.1.1 The catalytic converter shall be marked indelibly of manufacturer name or

trademark, type of the catalytic converter and direction of inlet and outlet.

5.1.2 The design, manufacture and installation of the catalytic converter shall ensure

that the vehicle comply with all provisions of national standards.

5.1.3 The design, manufacture and installation of the catalytic converter shall prevent

the possible corrosion or oxidation during the use of the vehicle, to a certain extent.

5.1.4 The design and manufacture of the catalytic converter shall ensure that when

the leakage test is carried out as specified in 6.1, its pressure drops shall not be greater

than 10 kPa. During the installation of the catalytic converter, it shall be ensured that

the interfaces are sealed.

5.1.5 The replacement catalytic converter shall be installed at the same position of

original equipment catalytic converter; the ground clearance of the vehicle shall not be

reduced; and the position of oxygen sensor in exhaust pipe shall not be altered.

5.1.6 The catalytic converter shall be provided with thermal insulation measures to

ensure use safety.

5.4.1 For original equipment catalytic converter, its endurance mileage is 80 000 km

under the conditions of normal use and maintenance of the vehicle.

5.4.2 For replacement equipment catalytic converter, its endurance mileage is 50 000

km under the conditions of normal use and maintenance of the vehicle.

5.5 Other performance requirements for replacement catalytic converter

5.5.1 Compared with the original equipment catalytic converter, the gas emission

back pressure shall not exceed 0.2 kPa when the replacement catalytic converter is

installed to carry out test as specified in 6.6.

5.5.2 Compared with the original equipment catalytic converter, the vehicle

acceleration noise shall not exceed 1 dB when the replacement catalytic converter is

installed to carry out test as specified in 6.7.

6.1 Leakage test

Apply the air of 200 kPa pressure in the sample; and measure the pressure drop within

30 s.

6.2 Preconditioning of catalytic converter

The sample for the catalytic converter shall be preconditioned as specified in 6.2. The

excess air coefficient of the engine during preconditioning is 1 ± 0.02; the airspeed of

the catalytic converter is (60 000 ± 600) h-1; the temperature at the inlet is above 700°C;

and the duration is 1 h.

6.3 Ignition temperature and air-fuel ratio characteristic test

Before test, the sample shall be preconditioned as specified in 6.2. The analytical

instruments and measuring instruments and sampling probes for test shall comply with

relevant provisions of GB/T 14762. The distance from the measuring point of inlet

temperature to the front-end face of carrier shall not be less than 300 mm.

6.3.1 Ignition temperature test

6.3.1.1 The excess air coefficient of the engine during test is 1 ± 0.02; and the

airspeed of the catalytic converter is (40 000 ± 400) h-1.

6.3.1.2 The inlet temperature is within the range of 200 ~ 500°C; change it gradually

by the interval not greater than 20°C; after the inlet temperature of the catalytic

converter becomes steady, measure the emission concentration values before and

after the catalytic converter. Plot the ignition temperature characteristic curve using the

inlet temperature as abscissa and the conversion coefficient as ordinate.

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