Abstract: A soot resistant and efficient diesel fuel reformer for a diesel exhaust aftertreatment system has serially arranged first and second catalyst supports. The first support is nearer the inlet and has a monolith structure that is uniform in the direction of flow. The second support has a modified monolith structure that is non-uniform in the direction of flow. Preferably, the first support has straight channels. Preferably, the second support has internal leading edges spaced periodically through its length to break up the flow. The first support has a catalyst coating comprising at least an oxidation catalyst. The second support has a catalyst coating comprising at least a steam reforming catalyst.

Abstract: Processes are provided for making partially coated monolith catalysts that are useful, for example, as pre-combustor catalysts for diesel exhaust aftertreatment. Monolith substrates are provided with interconnectivity and/or temporary barriers that allow from about 10 to about 90% of the monolith channels to be coated after the monolith substrate is assembled without having to carefully pick out among a large number of openings which ones to inject into or which ones to plug. The invention includes options of injecting into a multipath monolith substrate and of emplacing blocking material during monolith construction. Either catalyst coating material or coat-blocking material can be injected. Blocking materials allow the use of machinery for ordinarily non-selective processes, such as machinery for dip coating. Both multipath injections and pre-placed barriers can be used in a single partial coating process.

Abstract: A soot resistant and efficient diesel fuel reformer for a diesel exhaust aftertreatment system has serially arranged first and second catalyst supports. The first support is nearer the inlet and has a monolith structure that is uniform in the direction of flow. The second support has a modified monolith structure that is non-uniform in the direction of flow. Preferably, the first support has straight channels. Preferably, the second support has internal leading edges spaced periodically through its length to break up the flow. The first support has a catalyst coating comprising at least an oxidation catalyst. The second support has a catalyst coating comprising at least a steam reforming catalyst.

Abstract: An exhaust aftertreatment system is provided with a large channel combustor, a fuel reformer, and a lean NOX trap. The lean NOX trap is denitrated by steps comprising: heating the fuel reformer to steam reforming temperatures by introducing vaporized fuel to the large channel combustor and combusting a portion of the vaporized fuel under lean conditions, then making the exhaust-injected fuel mixture overall rich, whereby the fuel reformer produces syn gas that denitrates the lean NOX trap. The fuel reformer has a low thermal mass, whereby it is designed to heat to at least about 500° C. and catalyze steam reforming reaction with each denitration. The large channel combustor is a monolith having an average channel size larger than the fuel reformer and a thermal mass no more than about 20% that of the fuel reformer, whereby the large channel combustor facilitates low temperature startup of the fuel reformer.

Abstract: Processes are provided for making partially coated monolith catalysts that are useful, for example, as pre-combustor catalysts for diesel exhaust aftertreatment. Monolith substrates are provided with interconnectivity and/or temporary barriers that allow from about 10 to about 90% of the monolith channels to be coated after the monolith substrate is assembled without having to carefully pick out among a large number of openings which ones to inject into or which ones to plug. The invention includes options of injecting into a multipath monolith substrate and of emplacing blocking material during monolith construction. Either catalyst coating material or coat-blocking material can be injected. Blocking materials allow the use of machinery for ordinarily non-selective processes, such as machinery for dip coating. Both multipath injections and pre-placed barriers can be used in a single partial coating process.

Abstract: The invention provides devices and methods for generating H2 and CO in an O2 containing gas stream. The invention also provides devices and methods for removal of NOX from an O2 containing gas stream, particularly the oxygen-rich exhaust stream from a lean-burning engine, such as a diesel engine. The invention includes a fuel processor that efficiently converts added hydrocarbon fuel to a reducing mixture of H2 and CO. The added fuel may be a portion of the onboard fuel on a vehicle. The H2 and CO are incorporated into the exhaust stream and reacted over a selective lean NOX catalyst to convert NOX to N2. thereby providing an efficient means of NOX emission control.

Abstract: An exhaust aftertreatment system is provided with a large channel combustor, a fuel reformer, and a lean NOX trap. The lean NOX trap is denitrated by steps comprising: heating the fuel reformer to steam reforming temperatures by introducing vaporized fuel to the large channel combustor and combusting a portion of the vaporized fuel under lean conditions, then making the exhaust-injected fuel mixture overall rich, whereby the fuel reformer produces syn gas that denitrates the lean NOX trap. The fuel reformer has a low thermal mass, whereby it is designed to heat to at least about 500° C. and catalyze steam reforming reaction with each denitration. The large channel combustor is a monolith having an average channel size larger than the fuel reformer and a thermal mass no more than about 20% that of the fuel reformer, whereby the large channel combustor facilitates low temperature startup of the fuel reformer.

Abstract: The invention provides devices and methods for generating H2 and CO in an O2 containing gas stream. The invention also provides devices and methods for removal of NOX from an O2 containing gas stream, particularly the oxygen-rich exhaust stream from a lean-burning engine, such as a diesel engine. The invention includes a fuel processor that efficiently converts added hydrocarbon fuel to a reducing mixture of H2 and CO. The added fuel may be a portion of the onboard fuel on a vehicle. The H2 and CO are incorporated into the exhaust stream and reacted over a selective lean NOX catalyst to convert NOX to N2. thereby providing an efficient means of NOX emission control.

Abstract: The invention provides devices and methods for generating H2 and CO in an O2 containing gas stream. The invention also provides devices and methods for removal of NOx from an O2 containing gas stream, particularly the oxygen-rich exhaust stream from a lean-burning engine, such as a diesel engine. The invention includes a fuel processor that efficiently converts added hydrocarbon fuel to a reducing mixture of H2 and CO. The added fuel may be a portion of the onboard fuel on a vehicle. The H2 and CO are incorporated into the exhaust stream and reacted over a selective lean NOx catalyst to convert NOx to N2. thereby providing an efficient means of NOx emission control.

Abstract: A gas sampling system and method that utilizes a double aspirator design to precisely control the flow rate of a gas sample past a sensor (44, 46, or 48). The double aspirator design includes a primary aspirator (24) to draw a gas sample from the exhaust stack (14) at a first flow rate and a secondary aspirator (26) to draw a portion of the gas sample from the primary aspirator at a second flow rate past the sensors. In addition, a first pressure sensor (74) and second pressure sensor (76) are provided in order to monitor changes in the pressure differential across the sensor so that corresponding changes in the second flow rate can be accounted for by the control unit (18) when processing the measurement data from the sensor.

Abstract: This invention is a process for detecting low concentration levels of sulfur oxides (SO.sub.2) in a flowing gas stream (typically a combustion exhaust gas stream) and a catalytic SO.sub.2 sensor system which may be used in that process.

Abstract: This invention is a process for detecting low levels of nitrogen oxides (NO.sub.x) in a flowing gas stream (typically an exhaust gas stream) and a catalytic NO.sub.x sensor which may be used in that process.