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: A diesel engine exhaust aftertreatment system including a DPF and a LNT in that order is operated with simultaneous soot combustion and LNT desulfation. When a control signal to desulfate the LNT is generated, the DPF is heated to ignite combustion of trapped soot. As the trapped soot is combusting in the DPF, reductant is injected downstream of the DPF, but upstream of the LNT at a rate that leaves the exhaust rich, whereby the LNT undergoes desulfation. Soot combustion reduces the fuel penalty for desulfation by removing oxygen from the exhaust. When a reformer is configured upstream of the LNT, soot combustion helps stabilize the reformer operation. In one embodiment, there are two fuel injectors; one upstream of the DPF and one between the DPF and the fuel reformer. Methods are provided for using this type of configuration to operate the reformer when the DPF is not being regenerated.

Abstract: A vehicle is provided with a diesel engine, an exhaust treatment system including a LNT, and a controller configured to control the provision of a reductant to the exhaust for regenerating the LNT. The controller selectively provides the reductant to the exhaust based in part on a measure of whether the engine is undergoing a change in operating state. Preferably, the measure indicates if the engine is undergoing a speed or torque increase. During these types of transients, ideal conditions for LNT regeneration often occur. Ideal conditions include low exhaust oxygen concentrations combined with relatively low exhaust flow rates. Regenerating preferentially when these ideal conditions occur reduces the fuel penalty associated with LNT regeneration. These conditions also simplify regulating LNT and reformer temperatures. In a related concept, the transient is artificially created.

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: 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 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.

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: A circular cross-sectional fuel pipe can be prevented from undesired rotation in an engine cylinder head, by a key-key slot combination having a relatively small radial dimension. The key slot is formed by a groove formed in a cylindrical sleeve that is press fit in a counterbore machined in the cylinder head. The mating key can be a ball, or pin, or bar press fit into a side surface of the fuel pipe.