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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).

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.