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In prior work, the EGR loop catalytic reforming strategy developed by ORNL has been shown to provide a relative brake engine efficiency increase of more than 6% by minimizing the thermodynamic expense of the reforming processes, and in some cases achieving thermochemical recuperation (TCR), a form of waste heat recovery where waste heat is converted to usable chemical energy. In doing so, the EGR dilution limit was extended beyond 35% under stoichiometric conditions. In this investigation, a Microlith®-based metal-supported reforming catalyst (developed by Precision Combustion, Inc. (PCI)) was used to reform the parent fuel in a thermodynamically efficient manner into products rich in H2 and CO. We were able to expand the speed and load ranges relative to previous investigations: from 1,500 to 2,500 rpm, and from 2 to 14 bar break mean effective pressure (BMEP).

Use of catalytically coated short contact time (SCT) design approaches for application in mass transfer controlled reactors such as Auto Thermal Reformers (ATR's) is an area of much recent interest. Precision Combustion, Inc. (PCI) has developed an efficient and compact ATR using ultra-short channel length, high cell density SCT substrates (Microlith®). PCI has also extended this Microlith technology to other fuel processor reactors that operate at lower temperatures and are not mass transfer limited. Namely, reactors for the Water Gas Shift (WGS) and Preferential Oxidation (PROX) of CO have been developed. Due to the higher surface area per unit volume of the Microlith substrate compared to conventional monoliths, size advantages have been observed for these reactions, which are more kinetically controlled.

The performance of the fast lightoff, ultra-short metal monolith (SMM) catalyst technology was evaluated in a laboratory rig capable of simulating automotive exhaust streams. Tests focused primarily on determining the lightoff behavior of the fresh and engine aged catalyst over a wide range of air to fuel ratios (A/F). Experimental results are compared with estimates of mass transfer controlled operation for the geometry of the catalyst substrate. The effects of different space velocities, cycling between rich and lean gas streams, and addition of SO2 are also investigated. Additionally, the effect of thermal aging on the catalyst/substrate interface is discussed.

Reducing light-off time by using low thermal mass preconverters and increasing catalyst conversion efficiencies is one way of reducing cold start emissions and attaining mandated emission standards. Additionally, it is desirable to attain these features in a small, flexible package helping to overcome close coupling design constraints. Such a preconverter with an atypical Microlith™ metal catalyst substrate geometry and capable of withstanding high operating temperatures using a proprietary catalyst coating technique was tested with a conventional downstream ceramic main brick. This paper explains the physical characteristics and the flow dynamics of this substrate. Development and testing of prototypes were done on a bench scale apparatus and in automobiles. Bench scale catalyst performance and automotive FTP data before and after aging are presented. Automotive tests were done with and without secondary air and with calibrated Air/Fuel bias.

A low thermal mass, metal monolith, catalytic converter, was tested for reducing automotive emissions for applications both as lightoff and main converters. FTP testing was carried out to measure the first four minutes of Bag 1 emissions from a 2.2l, fuel-injected Plymouth Reliant, at New York State, Automotive Emissions Laboratory, Albany (NY-AEL). The car had aproximately 17,000 miles when tested and its driving history had been catalogued by NY-AEL. Both resistively heated and non-resistive mini-converter systems were tested in series with a conventional replacement new automotive converter. The non-resistive converter reduced HC, CO and NOx emissions by more than 50%, 40% and 30%, respectively. despite excess air addition. Lightoff occurred within 10 seconds of engine start. A modified cycle exploring steady state conditions under load showed greater than 70% reduction in NOx.