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It is well known that hydrocarbon reduction during a cold start is a major issue in achieving ultra low emissions standards. This paper describes one of the possible approaches for reducing the cold-start hydrocarbon emissions by using a fast “light-off” planar oxygen sensor. The goal of this study was to verify the operation characteristics of Delphi's fast “light-off” planar oxygen sensor's (INTELLEK OSP) operating characteristics and the closed-loop performance for achieving improved hydrocarbon control for stringent emission standards. Tests were conducted in open-loop and closed-loop mode under steady and transient conditions using a 1996 model year 2.4-liter DOHC in-line 4-cylinder engine with a close-coupled catalytic converter. Overall performance of the OSP showed relatively quick reaction time to reach the operating temperature.

A designed experiment was conducted to determine the effects of varying noble metal concentration, converter volume, substrate material, aging schedule, and performance engine on FTP efficiency. Sixteen catalytic converters of common containment and washcoat technology were aged and evaluated on 3.8 L and 5.7 L engine dynamometers using the cold start FTP as the performance test. Gaseous conversion efficiencies for Cycle 2 (light-off), Phase 2 (steady state), and End of Test Summary are compared for the five main factors and their interactions.