Abstract: A method is disclosed for regenerating a diesel particulate filter without excessively increasing NO2 emissions. The system includes a fuel delivery device, an oxidation catalyst, and a diesel particulate filter. During a first operational mode, the fuel injection device injects a relatively smaller amount of fuel into the exhaust stream to reduce the capacity of the oxidation catalyst to oxidize NO in the exhaust stream to NO2. At a determined time, a second operational mode is initiated where a relatively larger amount of fuel is injected into the exhaust stream and is oxidized within the oxidation catalyst, thereby raising the exhaust temperature sufficiently to combust substantially all of the soot trapped on the diesel particulate filter.

Abstract: A method is disclosed for regenerating a diesel particulate filter without excessively increasing NO2 emissions. The system includes a fuel delivery device, an oxidation catalyst, and a diesel particulate filter. During a first operational mode, the fuel injection device injects a relatively smaller amount of fuel into the exhaust stream to reduce the capacity of the oxidation catalyst to oxidize NO in the exhaust stream to NO2. At a determined time, a second operational mode is initiated where a relatively larger amount of fuel is injected into the exhaust stream and is oxidized within the oxidation catalyst, thereby raising the exhaust temperature sufficiently to combust substantially all of the soot trapped on the diesel particulate filter.

Abstract: A diesel exhaust treatment system is disclosed that includes first and second diesel particulate reduction devices. The first diesel particulate reduction device is located upstream in the exhaust flow and contains an oxidation catalyst coating. The second particulate reduction device is located downstream from the first particulate reduction device and is generally non-catalyzed or lightly catalyzed. Each particulate reduction device comprises a flow-through fabric-type filtration media with substantial internal turbulence. As exhaust gas passes through the catalyzed upstream particulate reduction device, nitric oxide (NO) is oxidized to form nitrogen dioxide (NO2), a portion of which interacts with the particulate trapped within the upstream diesel particulate reduction device to regenerate the upstream device.

Abstract: A system or method for controlling the delivery of fuel into the transient flow of an exhaust system to control emissions. A mathematical model representative of the exhaust system can be used to determine, based on operating conditions of the exhaust system, a rate of fuel delivery suitable for achieving a desired result. The desired result can be to increase the temperature of a diesel particulate filter to a temperature suitable for regeneration without exceeding a temperature that may damage the diesel particulate filter.

Abstract: Methods for estimating the mass flow rate of NOx in an exhaust stream by correlating the level of NOx to an engine parameter. The level of NOx can be estimated as a function of engine power, of intake pressure, of exhaust temperature, as a function of the percentage of O2 in the exhaust stream, or as a combination of any of these. Once the level of NOx is approximately known, the exhaust system of the engine system can be modified to improve the removal efficiency of NOx and exhaust particulate matter from the exhaust stream. These methods for estimating the NOx mass flow rate can be used for an exhaust configuration that includes a lean NOx catalyst (LNC), a selective catalytic reduction (SCR) catalyst, or a lean NOx trap (LNT). A particulate filter can be present in the exhaust configuration.

Abstract: A muffler is described for muffling both positive power and compression brake type engine retarders. The muffler includes an outer shell defining an internal volume. A first, inner, perforated wall is spaced from the outer shell and defines a first, annular, volume therebetween. A first volume of packing material is positioned within the annular volume. An inlet tube is oriented within the internal volume. In certain embodiments, the inner perforated wall circumscribes at least a portion of the inlet tube, and extends a distance of at least 25% of the axial length of the outer wall. Both single and dual muffler systems are described. Methods of use and operation are also provided.

Abstract: A muffler is described for muffling both positive power and compression brake type engine retarders. The muffler includes an outer shell defining an internal volume. A first, inner, perforated wall is spaced from the outer shell and defines a first, annular, volume therebetween. A first volume of packing material is positioned within the annular volume. An inlet tube is oriented within the internal volume. In certain embodiments, the inner perforated wall circumscribes at least a portion of the inlet tube, and extends a distance of at least 25% of the axial length of the outer wall. Both single and dual muffler systems are described. Methods of use and operation are also provided.