Abstract: One aspect of the invention relates to a clean power generation system in which an internal combustion engine is operated to produce shaft power and an exhaust stream. The exhaust stream is processed by a fuel cell. Fluctuations in power demand are met, at least in part, by increasing or decreasing power output from the fuel cell and/or power uptake or output from a power storage device. The engine can operate at a relatively constant rate, providing a steady exhaust stream, which facilitates pollution control and fuel cell operation. According to another aspect of the invention, the exhaust of an engine is treated with a fuel cell having an electrolyte that conducts protons. In addition to removing pollutants from the exhaust while generating useful power, the fuel cell can provide a supply of low acidity water. The water can be used in the fuel reformer.

Abstract: A power generation system comprising a LNT for exhaust aftertreatment. The LNT has an effective operating temperature range. When the LNT is near a limit of its effective operating temperature range, the transmission is used to select operating points that increase the LNT's effectiveness. Generally, these operating points reduce the exhaust flow rate, although other factors such as the exhaust temperature may also be taken into account in selecting the operating points. Preferably, the LNT's effective operating temperature-range includes exhaust temperatures produced by the engine at its point of peak power output, whereby the LNT does not approach the limits of its effective operating temperature range except when the engine is at less than peak power. At lower power levels, it is generally possible to select operating points that provide lower exhaust flow rates than the flow rate occurring at the peak power level.

Abstract: A method is provided for regenerating a LNT in a diesel engine exhaust aftertreatment system. Typically, the aftertreatment system comprises a fuel reformer, a LNT, and a SCR catalyst in that order. Over the course of the regeneration, the concentration or flow rate of syn gas is increased, peaked, and then reduced. Preferably, the syn gas concentration or flow rate and the fuel reformer temperature are simultaneously controlled using at least a fuel injector and an engine intake air throttle. The pattern of increasing the syn gas concentration or flow rate during a first part of the regeneration and decreasing the syn gas concentration of flow rate in a latter part of the regeneration reduces the fuel penalty for the regeneration and improves the ammonia production rate as compared to a system in which the syn gas concentration or flow rate is essentially constant throughout the regeneration.

Abstract: A power generation system comprises a diesel engine, a diesel particulate filter and a LNT configured to receive the exhaust from the DPF. The DPF is provided with a catalyst coating that is functional to catalyze methanation of trapped soot with H2 contained in the exhaust. Preferably, the catalyst has little or no oxygen storage capacity. The system is configured to regenerate the LNT by providing syn gas to the exhaust in rich regeneration phases. The syn gas-containing exhaust passes through the DPF and then the LNT. Within the DPF, the syn gas-containing exhaust removes soot be methanation and other soot gasification reactions, thus reducing or eliminating the need to reduce the DPF by other means. Soot gasification is preferred over soot combustion in that soot gasification avoids the destructive high DPF temperatures associated with soot combustion.

Abstract: One concept relates to power generation system, comprising a diesel engine, an exhaust manifold, a turbocharger, and an exhaust line in which are configured a fuel reformer and a LNT. A fuel injector is configured to inject fuel into the manifold upstream of the turbine. The high temperatures upstream of the turbine cause the fuel to crack into smaller molecules, releasing heat and providing a boost to the turbocharger. The fuel injected into the manifold also undergoes intense mixing as it passes through the turbocharger. Injecting fuel in this manner provides several benefits for reformer operation. Another concept relates to a manifold fuel injector used to provide fuel for heating a DPF.

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 including a lean NOx trap, an ammonia-SCR catalyst, and an additional catalyst configured in between. The lean NOx trap adsorbs NOx from lean exhaust and produces ammonia during regeneration. The SCR catalyst adsorbs most of that ammonia and subsequently uses that ammonia to reduce NOx. The additional catalyst is adapted to reduce the concentration of hydrocarbons in the exhaust during LNT regeneration and thereby mitigate hydrocarbon poisoning of the SCR. In one embodiment, the additional catalyst is a hydrocarbon-SCR catalyst. In another embodiment, the additional catalyst is an oxidation Catalyst. In a further embodiment, the additional catalyst is a hydrocarbon adsorbent. An oxidation catalyst can be made to store oxygen for hydrocarbon oxidation while avoiding excessive oxidation of ammonia by appropriately limiting that oxygen storage capacity.

Abstract: The present invention provides systems and methods to improve the performance and emission control of internal combustion engines equipped with nitrogen oxides storage-reduction (“NSR”) emission control systems. The system generally includes a NSR catalyst, a fuel processor located upstream of the NSR catalyst, and at least one fuel injection port. The fuel processor converts a fuel into a reducing gas mixture comprising CO and H2. The reducing gas mixture is then fed into the NSR catalyst, where it regenerates the NSR adsorbent, reduces the NOx to nitrogen, and optionally periodically desulfates the NSR catalyst. The fuel processor generally includes one or more catalysts, which facilitate reactions such as combustion, partial oxidation, and/or reforming and help consume excess oxygen present in an engine exhaust stream. The methods of the present invention provide for NSR catalyst adsorbent regeneration using pulsed fuel flow. Control strategies are also provided.

Abstract: A method of operating a power generation system involves operating a diesel engine to produce exhaust that is passed first through a combined DPF-fuel reformer and then a LNT. In response to the control signal to regenerate the LNT, fuel is injected into the exhaust at a rate that leaves the exhaust lean, whereby the injected fuel combusts in the combined DPF-reformer, warming it. There follows a rich phase in which fuel is injected into the exhaust at a rate that leaves the exhaust rich, whereby the DPF-reformer produces reformate and the LNT is regenerated. The combined DPF-reformer undergoes a regeneration that removes accumulated particulate matter with each LNT regeneration. Preferably, the DPF-reformer has a low thermal mass to facilitate heating. Preferably, the DPF-reformer includes a soot gasification catalyst, whereby a substantial amount of particulate matter is removed from the DPF-reformer during the rich phases.

Abstract: A fuel reformer is configured in an exhaust line upstream of a LNT. To desulfate the LNT, over a first period, fuel is provided to the exhaust to make the exhaust rich. While producing reformate, the reformer is allowed to heat to a relatively large extent, typically at least about 75° C. Before the reformer overheats, the provision of fuel is reduced and typically stopped entirely for a second period, over which the reformer cools. The heating and cooling periods are repeated to complete the desulfation process. The reduced efficiency of operating the reformer over an extended temperature range is more than compensated for by the benefits of extending the rich pulse.

Abstract: An exhaust aftertreatment system comprising two or more branches, at least one of which contains a NOx adsorber-catalyst. The branches unite downstream into a trailing conduit that contains an ammonia-SCR catalyst. Ammonia generated by the NOx adsorber-catalyst during regeneration is stored for later use by the SCR catalyst. One advantage of this configuration is a continuous or near continuous presence of oxygen within the trailing exhaust conduit. The continuous presence of improves the efficiency of the SCR catalyst. Another concept is to configure a multi-branch exhaust aftertreatment system without valves, dampers, or other electronically controlled devices adapted to selectively alter the distribution of the exhaust between the branches. The absence of such devices generally results in a comparatively balanced division of exhaust between the branches. One benefit of this configuration is improved reliability as compared to systems that use valves.

Abstract: The invention relates to systems and methods of detecting faults in an exhaust line fuel injection system. An expected relationship between a temperature within the exhaust system and a commanded fuel injection rate or amount is compared to an actual relationship in order to detect faults. The temperature is preferably a temperature of, within, or downstream of an exhaust system device that catalyzes an oxidation or partial oxidation reaction of the fuel, such as an oxidation catalyst or a fuel reformer. The expected relationship may be defined in terms of a thermal model of a system comprising the catalytic device. The invention can be used to detect spray quality faults or to detect fuel injector faults without the use of flow meter.

Abstract: In an exhaust aftertreatment system comprising a NOx adsorber-catalyst followed by an SCR catalyst, means are provided for preventing the SCR catalyst from becoming heated to near the same peak temperatures as the NOx adsorber-catalyst during desulfation. In one embodiment, the means is a thermal mass between the NOx adsorber-catalyst and the SCR catalyst. In another embodiment, the means is a valve configured to selectively divert exhaust leaving the NOx adsorber-catalyst from the SCR catalyst. In a method of the invention, the NOx adsorber-catalyst temperature is cycled during desulfation. The peaks of the cycles are within an appropriate temperature range for desulfating the NOx adsorber-catalyst, but the average temperature is below the temperature range at which the SCR catalyst is damaged. The temperature peaks are damped as they travel from the NOx adsorber-catalyst to the SCR, whereby the SCR experiences much lower peak temperatures than the NOx adsorber-catalyst.

Abstract: Described here are systems and methods for treating fuel injected exhaust streams. In general, the systems comprise a fuel injector, a pre-combustor, and a fuel combustor. The methods described herein include methods for regenerating a NOx trap or a DPF, and methods for generating a substantially uniform fuel air mixture at a fuel combustor inlet, or a substantially uniform temperature at a fuel combustor outlet. The methods of regenerating a NOx trap typically comprise the steps of injecting fuel into an exhaust stream, passing the stream through a pre-combustor, operating the pre-combustor to at least partially combust the injected fuel, reacting the fuel and exhaust stream mixture within a fuel combustor to generate a reducing gas mixture, and introducing the reducing gas mixture into a NOx trap, whereby the NOx trap is regenerated. Similar methods for regenerating a diesel particulate filter are also described. Control strategies are also provided.

Abstract: The invention relates to a power generation system with a continuously operating fuel reformer. Preferably, the fuel reformer is either off, warming up, or operating with an essentially constant fueling rate. Some of the reformed fuel is intermittently used to regenerate a NOx trap that treats the exhaust of an internal combustion engine. Any reformed fuel not used for other purposes is supplied to a fuel cell. The fuel reformer does not shut down between NOx trap regeneration cycles except when the engine is also shut down. The invention substantially eliminates issues of reformer response time as they relate to NOx trap regeneration.

Abstract: One aspect of the invention relates an exhaust treatment system having an SCR reactor following a NOx adsorber. Syn gas is used to regenerate the NOx adsorber. Another aspect relates to an LNT/SCR provided with an ammonia source separate from the LNT. A further aspect relates to a system comprising first and second LNTs and one or more SCRs downstream of the LNTs. A still further aspect relates to a device comprising first and second NOx adsorbers contained in a single housing. Another aspect relates to coating a surface of a moving part in an exhaust system with an oxidation catalyst to mitigate fouling. Additional aspects of the invention relate to strategies for controlling one or more of the time to initiate a regeneration cycle, the time to terminate a regeneration cycle, and the reductant injection rate during regeneration of LNT/SCR exhaust treatment systems.

Abstract: The invention relates to a fluid power accumulator in which the fluid undergoes a state change as the system is pressurized to store energy. A state change can be a phase change, a chemical reaction, or a combination of these. Generally the state change results from the interaction of a compressible fluid contained in the accumulator with another substance, which can be a fluid or a solid. Preferably, the state change includes the physical adsorption of a fluid by a solid adsorbant. The invention can improve the energy storage density of a fluid power accumulator, allow a given energy storage density to be achieved at a lower maximum pressure, facilitate heat transfer and storage within an accumulator, and/or improve accumulator efficiency by storing energy in a form other than thermal energy, such as in the form of chemical energy.

Abstract: The invention relates to systems for removing NOx from exhaust. In one aspect of the invention, after adsorption, an NOx adsorber is isolated from the main exhaust flow and desorption induced by raising the temperature. The desorbed NOx is combined with a reductant and reduced over a catalyst. Preferably, the reductant is syn gas produced in an on-board reformer. The catalyst need never be exposed to the main exhaust flow, which is particularly advantageous for catalysts sensitive to water, oxygen, or sulfur. In another aspect of the invention, a recirculating flow is induced through an NOx adsorber during a regeneration cycle. Recirculation can induce greater desorption at a given temperature, provide a source of heat for the adsorber, and allow a higher conversion rate with a fixed amount of catalyst. A further aspect of the invention relates to a vehicle-mounted adsorbers with provisions for heating.

Abstract: One or more parameters for denitration or desulfations of a LNT is varied, whereby the saturation of NOx and/or SOx in the LNT is reduced to a lower level when an operating state makes the LNT otherwise less effective or places a greater demand for conversion efficiency on the LNT. The operating state can relate to whether the LNT is at the limit of its effective operating temperature range, a degree of poisoning, or an engine operating state. Selectively tolerating high degrees of sulfur poisoning or NOx saturation during periods of low exhaust flow allows the efficiency of denitrations and/or desulfations to be increased over a large portion of a vehicle's operating cycle, particularly when the engine uses a CVT. Another concept relates to a power generation system comprising an engine tuned to efficiently operate in a narrow speed range for all levels of power output.

Abstract: One aspect of the invention relates to a particulate filter useful in treating exhaust from a diesel-power vehicle. The particulate filter comprises filter elements for removing particulate matter and an ammonia SCR catalyst. Ammonia can be produced during regeneration of an NOx adsorbant. The adsorbant can be contained in a separate device upstream of the particulate filter or be incorporated within the particulate filter. Another aspect of the invention relates to a method of cleaning exhaust comprising passing the exhaust over an NOx adsorber to adsorb a portion of NOx from the exhaust; passing the exhaust through a particulate filter to remove particulate matter from the exhaust; and removing a further portion of NOx from the exhaust by reducing it with ammonia over an ammonia SCR catalyst. Preferably, a catalyst contained within the adsorbant provides NO2 for continuously regenerating the particulate filter.