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A new adsorber system for reducing cold start HC emissions has been developed that offers a passive and simplified alternative to previous HC adsorber technologies. The series flow in-line adsorber concept combines existing catalyst technology with a zeolite based HC adsorber by simply incorporating one additional adsorber catalyst substrate into conventional catalytic converters without any valving, purging lines or special substrates. The HC adsorber catalyst consist of a durable zeolite, a washcoat binder, precious group metals and rare earth promoters on standard monolithic substrates. For selected vehicle applications, a single converter containing a light off catalyst, a catalyzed HC adsorber and a standard three-way catalyst can be used in the underfloor position. Even after severe engine aging, the vehicle FTP results show that this new technology remains effective in reducing the cold start HC emissions while providing good CO and NOx conversions.

Regulations are being considered or have already been enacted to limit the exhaust emissions of hydrocarbons, CO and NOx from small engines, such as those used in the lawn and garden industry. One of the most promising ways for engine manufacturers to comply with current and future emission standards is through the use of catalysts. However, these small engines provide an environment with a number of challenges for emission catalyst activity and durability which are not found with automotive exhaust, which is traditionally where catalysts of this type have been used. Problems unique to the small engine can include extremely short catalyst residence times, high hydrocarbon and carbon monoxide to oxygen ratios, overall high levels of emissions leading to high reaction exotherms, and pertubated flow due to single cylinder operation. A number of catalyst variables were tested using 4-stroke engines.

Development of more fuel efficient passenger vehicle engines based on lean burn technologies presents several challenges for controlling the emissions of regulated pollutants. Thus far, the emphasis has been on the selective reduction of NOx in the presence of excess O2. However, certification of vehicles based on lean burn technologies, whether gasoline or diesel, will require compliance with all regulated gas emission levels. Current working hypotheses on the origin of activity in lean NOx reduction catalysts will place strains on other aspects of the overall emissions system. Using the FTP-75 certification cycle as a basis for evaluation, the implications of using effective lean burn catalysts will be discussed. In particular, the requirement of ultralow hydrocarbon emissions has invoked strategies seemingly contradictory to the effective use of lean NOx catalysts. Possible alternative solutions and their consequences will be discussed.

The adoption of significantly more stringent tailpipe emission standards is leading the domestic car manufacturers and oil companies to reexamine the composition of commercial gasolines. One offshoot of this examination is a cooperative inter-industry Auto/Oil Air Quality Improvement Research Program. This study will attempt to determine the potential reductions in total vehicle emissions and resultant improvements in air quality from the use of reformulated gasolines. One important aspect of the program is to determine the effect of variable aromatic and olefinic hydrocarbon content as well as variable levels of oxygenates on emission levels from a statistically-designed vehicle program. Much laboratory, engine and vehicle emission data has been generated over the past two decades that is potentially useful in interpreting the tailpipe emission patterns associated with proposed fuel composition changes.