Search Results

The Emissions Research Laboratory (ERL) of the Arizona Department of Environmental Quality (ADEQ) has developed tests to determine, in situ, both the oxidation and reduction capabilities of light duty, spark ignition vehicle catalysts. The tests require minimal system intrusion; determination of oxidation efficiency is essentially nonintrusive, but reduction efficiency measurement requires replacement of the oxygen sensor with a high precision universal exhaust gas oxygen (UEGO) sensor. The vehicle is operated on a dynamometer at 40mph steady state using the IM240 specified loading for that vehicle. To ensure proper fueling, the engine-out A/F ratio is measured. This measurement can be taken at the tailpipe with secondary air injection disabled, if present. Oxidation efficiencies for hydrocarbon (HC) and carbon monoxide (CO) require normal vehicle configuration (secondary air active, if present) and tailpipe measurements of total HC and methane (CH4).

The 1990 amendment to the Clean Air Act (CAA) mandates enhanced inspection and maintenance (I/M) programs for the three most severely polluted nonattainment area classes. The State of Arizona Emissions Research Laboratory (ERL) is currently studying alternative methods, procedures, and equipment to determine the minimum technological limits required to produce acceptable Federal Test Procedure (FTP) correlative data and avoid excessive test precision losses. The first phase of the study, development of the driving trace, has shown that a 95 second loaded transient test (AZ95) yields results that are statistically similar to the 240 second loaded transient test (IM240) with respect to test repeatability and correlation to FTP derived tailpipe emissions.

A gas-liquid chromatographic system designed for analysis of methanol in exhaust from methanol/gasoline fueled vehicles is described. Modifications of this system for liquid analysis of methanol in gasoline, and analysis of ethanol in exhaust from ethanol/gasoline fueled vehicles are also discussed. Some results for methanol in exhaust from neat methanol and methanol/ gasoline fueled vehicles are presented, and are compared to emissions measured by a total hydrocarbon analyzer using flame ionization detection.