Section R18-2-1031. Standards for Evaluating the Oxidation Effi- ciency of a Catalytic Converter

A.      Except for a vehicle requiring an Idle-Only Inspection, a gaso- line-powered vehicle requiring a catalytic converter test under R18-2-1008(C) shall be tested using the following Catalyst Efficiency Test Procedure:

1.        Immediately after a vehicle completes an Inspection and Maintenance (I/M) test in the waiver lane, the exhaust sampling cone shall be removed from the tailpipe. The vehicle shall remain on the dynamometer with the engine idling and the transmission in neutral. The vehicle engine must be at normal operating temperature.

2.        For the catalyst test, the dynamometer and the constant volume sampler shall remain at the settings used for the vehicle’s I/M test.

3.        The inspector shall insert the sampling tube for the A/F analyzer into the tailpipe of the vehicle.

4.        The inspector shall accelerate the vehicle to 40 ± 2.5 MPH and maintain a steady-state operating mode for the duration of the test. Once the vehicle obtains the test speed, the test shall begin.

5.        Once the test begins, a two-minute stabilization period shall take place, during which the inspector shall monitor the A/F analyzer to ensure that the A/F is 14.0 or greater. If the mean A/F is less than 14.0, the inspector shall abort the test.

6.        If the A/F is 14.0 or greater, the exhaust sampling cone shall be repositioned for exhaust sampling.

7.        After the stabilization period ends, the total hydrocarbon and methane concentrations and the A/F ratio shall be continuously recorded for two minutes.

Department of Environmental Quality – Air Pollution Control

8.        At the end of the two-minute sampling period, the inspec- tor shall stop the vehicle, remove the exhaust sampling cone and the A/F analyzer sampling probe from the tail- pipe, and remove the vehicle from the dynamometer.

9.        The mean total hydrocarbon concentration shall be divided by the mean methane concentration for the recorded values of the test, to produce a ratio (R) of total hydrocarbon to methane. The ratio, R, shall be applied to the formula: Catalyst Efficiency (%) = -3 (R) +100.

10.     A vehicle passes the test if the Catalyst Efficiency (%) is 75% or greater.

11.     The test result for a non-passing vehicle with a mean A/F equal to, or less than, 14.3 shall be inconclusive.

12.     A vehicle fails the Catalyst Efficiency Test Procedure if the A/F is greater than 14.3 and the Catalyst Efficiency (%) is less than 75%. The failing vehicle cannot be granted a waiver according to R18-2-1008(C)(1).

B.       Analytical equipment required to perform the Catalyst Effi- ciency Test Procedure shall meet the following requirements:

1.        Analyzer Specifications:

a.         An analyzer shall meet performance specifications of 40 CFR 86 subparts B, D, and N with respect to accuracy, precision, drift, interference, and noise. 40 CFR, subparts B, D, and N, adopted as of July 1, 1998, are incorporated by reference and on file with the Department and the Secretary of State. This incorporation contains no future editions or amend- ments. A copy of this referenced material may be obtained from the U.S. Government Printing Office, Superintendent of Documents, Mail Stop SSOP, Washington D.C. 20402-9328.

b.       

	gle range with a calibration curve covering at least 0	Rating (Pounds)	Engine Size	Speed	Load
	to 300 ppm carbon.			(MPH)	(HP)
c.	Methane analysis shall be determined by a flame	8500 or less	4 cyl. or less	22-25	2.8-4.1
	ionization  detector   equipped  with  a  non-methane	8500 or less	5 or 6 cyl.	29-32	6.4-8.4
	cutter capable of oxidizing 98% of the hydrocarbons	8500 or less	8 cyl. or more	32-35	8.4-10.8
	(except methane) while more than 90% of the meth-	8501 or more	All	37-40	12.7-15.8

  

 

Total hydrocarbon analysis shall be determined by a flame ionization detector. The analyzer shall be sin-

ane remains unchanged. The analyzer shall be single range with a calibration curve covering at least 0 to 30 ppm.