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A laboratory flow reactor study was utilized to determine the durability impact of alkali metal (Na and K) exposure on three Pt/Pd-based diesel oxidation catalysts (DOC), two vanadium-based selective catalytic reduction (SCR) catalysts, and two Cu/zeolite-based SCR catalysts. All catalyst samples were contaminated by direct deposition of Na or K by an incipient wetness technique. The activity impact on the contaminated DOCs was accomplished by evaluating for changes in CO and HC light-off. The activity impact on the contaminated SCR catalysts was accomplished by evaluating for changes in the Standard SCR Reaction, the Fast SCR Reaction, the Ammonia Oxidation Reaction, and the Ammonia Storage Capacity. Contamination levels of 3.0 wt% Na was found to have a higher negative impact on Pt-based and zeolite containing DOCs for T-50 CO and HC light-off.

High gas prices combined with demand for improved fuel economy have prompted increased interest in diesel engine applications for both light-duty and heavy-duty vehicles. The development of aftertreatment systems for these vehicles requires significant investments of capital and time. A reliable and robust qualification testing procedure will allow for more rapid development with lower associated costs. Qualification testing for DPFs has its basis in methods similar to DOCs but also incorporates a PM loading method and regeneration testing of loaded samples. This paper examines the effects of accelerated loading using a PM generator and compares PM generator loaded DPFs to engine dynamometer loaded samples. DPFs were evaluated based on pressure drop and regeneration performance for samples loaded slowly and for samples loaded under accelerated conditions. A regeneration reactor was designed and built to help evaluate the DPFs loaded using the PM generator and an engine dynamometer.

Diesel vehicle applications are being tasked with increasingly stringent particulate emissions regulations. These regulations will require the use of Diesel Particulate Filters (DPFs). Prior to on-vehicle studies, DPF qualification studies are performed in laboratory bench reactors. In order to provide representative performance data, these studies require the testing of samples loaded with carbonaceous soot particles. A new soot generator, utilizing a pressure controlled propane flame, has been designed and built for this purpose. Soot production rates are on the order of approximately 8 mg/min at a concentration of 180 mg/m3. This allows 8 inch long cores to be loaded in 1 hour to soot concentrations encountered in typical vehicle operation. The soot generator allows for the selection of two distinct size distributions similar to typical diesel exhaust: a 57 nm peak and a 76 nm peak.

This paper describes the pressure loss characteristics of a variety of substrates (with and without washcoat) that have different cell densities, lengths, and diameters. Both experimental and analytical approaches were used to determine pressure loss characteristics. Engine dynamometer testing was conducted as an experimental approach to measure pressure losses at several different speed and load points. A simple, but comprehensive, analytical model was also developed to estimate pressure loss and equivalent power loss in an exhaust system. The model provides for losses due to the substrate resistance and the inlet/outlet headers. The experimental approach demonstrated that the model was an effective tool to provide assistance during the screening of exhaust system design alternatives.

This paper summarizes some of the research which has been carried out at Ford Motor Co. in the area of NOx traps. Results from a large body of experimental work are reviewed and used to provide insight into the fundamental processes which govern NOx trap performance. In particular, the key parameters which control thermal durability and sulfur poisoning of the NOx trap are discussed in detail. In addition, a theoretical model of the NOx trap is described and used in the analysis and interpretation of the experimental results.

The pulse flame combustor was adapted by researchers at Ford Motor Company in the early 1970s in order to produce exhaust gas simulating the combustion products of the internal combustion engine for the evaluation of automotive catalysts. Over the years, the pulse flame combustor has found application in a wide variety of research oriented tasks associated with automotive catalysts and emissions. More recent research and development efforts which have resulted due to elevated demands toward lower vehicle emission levels have prompted continuing refinements of the apparatus and effected innovative approaches to the study of emerging automotive catalyst and emission control issues with the pulse flame combustor. This report provides an overview of the operation and design evolution of the pulse flame combustor. In addition, recent applications of this laboratory device for studying automotive catalysts, alternative fuels, and other automotive emission control topics are reviewed.

A new laboratory test for measuring catalyst oxygen storage capacity has been developed. The test accurately predicts catalyst performance on the vehicle during transient A/F excursions and correlates well with vehicle CO and Nox tailpipe emissions. The test was subsequently used to facilitate improved oxygen storage capacity for new Pd-only washcoat formulations.

This paper provides an overview of the dual EGO sensor method for OBD-II catalyst efficiency monitoring. The processes governing the relationship between catalyst oxygen storage, HC conversion efficiency, and rear EGO sensor response are reviewed in detail. A simple physical model relating catalyst oxygen storage capacity and rear EGO sensor response is constructed and used in conjunction with experimental data to provide additional insight into the operation of the catalyst monitor. The effect that the catalyst washcoat formulation has in determining the relationship between catalyst oxygen storage capacity and HC conversion efficiency and its impact on the catalyst monitor is also investigated. Lastly, the effects of catalyst failure mode, fuel sulfur, and the fuel additive MMT on the catalyst monitor's ability to properly diagnose catalyst function are discussed.