Abstract:
Systems and methods for reducing NOx emissions using a branched exhaust system with a first and second turbine including an emission-control device containing a zeolite, are described. In one example approach, a method comprises: during a first duration when exhaust temperature is below a first temperature threshold, directing exhaust gas through the second turbine and the emission-control device, and adjusting the second turbine to control intake boost; and during a second duration following the first, directing exhaust gas through the first turbine, and adjusting the first turbine to control intake boost. In this way, the first and second turbines may provide a greater degree of boost control in order to reduce boost fluctuations while enabling storing cold start NOx emissions for later reduction.
Abstract:
Systems and methods for reducing NOx emissions using a branched exhaust system with a first and second turbine including an emission-control device containing a zeolite, are described. In one example approach, a method comprises: during a first duration when exhaust temperature is below a first temperature threshold, directing exhaust gas through the second turbine and the emission-control device, and adjusting the second turbine to control intake boost; and during a second duration following the first, directing exhaust gas through the first turbine, and adjusting the first turbine to control intake boost. The emission-control device may be purged when exhaust temperature is above a second temperature threshold higher than the first temperature threshold, where during the second duration exhaust gas does not flow through the emission-control device.
Abstract:
An internal combustion engine exhaust gas recirculation system. A turbine section of a turbocharger is coupled to an exhaust manifold of the engine. A compressor section has an output coupled to an intake manifold of the engine. The exhaust gas aftertreatment system is coupled to an output of the turbine section. The exhaust gas aftertreatment system includes a particulate filter having: a housing of an outer wall and an inner wall; a particulate filtering section disposed within the inner wall of the housing; and a channel formed between the inner wall and the outer wall. The channel created by the outer wall includes: an inlet disposed downstream of the filtering section for receiving a portion of exhaust gasses exiting the filtering section, and an outlet coupled to the input of the compressor section of the turbine for transporting the exhaust gasses received by the inlet of the channel to an input of the compressor section.
Abstract:
A system and a method for delivering a liquid to an exhaust-aftertreatment device in a motor-vehicle. The system includes a dispenser configured to contain a liquid, a vertical cross-section of the dispenser having opposing first and second wall segments, a horizontal distance between the first and second wall segments at the level of the liquid increasing continuously as the level descends from a substantially full level to a substantially empty level. The system further includes, inside the dispenser, one or more substances that may include the liquid and a solid derived by freezing the liquid, and, a liquid conduit penetrating the dispenser and configured to conduct at least some of the liquid from the dispenser to the exhaust-aftertreatment device. The system may further include a controller configured to control a flow of the liquid from the dispenser, and a heater operatively coupled to the controller and configured to provide heat to at least a bottom portion of the dispenser.
Abstract:
A method and a system for improved reductant delivery to an exhaust gas aftertreatment device for a lean burn internal combustion engine exhaust are presented. The system includes a heated evaporator unit into which a mixture of reductant and air in injected, wherein the mixture is vaporized and introduced into the exhaust gas aftertreatment device. Introducing the reductant mixed with air into the heated evaporator unit prevents lacquering and soot deposits on the heated element housed inside the unit, and also speeds up the vaporization process due to better reductant distribution thus reducing system response delays and improving conversion efficiency of the exhaust gas aftertreatment device. The reductant delivery system is further improved by adding a catalyst to it, and by preventing the reductant and air mixture from coming into direct contact with the surface of the heating element.
Abstract:
A method and a system for improved reductant delivery to an exhaust gas aftertreatment device for a lean burn internal combustion engine exhaust is presented. The system includes a heated evaporator unit into which a mixture of reductant and air in injected, wherein the mixture is vaporized and introduced into the exhaust gas aftertreatment device. Introducing the reductant mixed with air into the heated evaporator unit prevents lacquering and soot deposits on the heated element housed inside the unit, and also speeds up the vaporization process due to better reductant distribution thus reducing system response delays and improving conversion efficiency of the exhaust gas aftertreatment device. The reductant delivery system is further improved by adding a catalyst to it, and by preventing the reductant and air mixture from coming into direct contact with the surface of the heating element.
Abstract:
A liquid dispenser includes an exterior surface and an interior surface. The interior surface encloses a volume that tapers outwardly in a downward direction so that any horizontal cross-section of the volume fits inside each horizontal cross-section below it from a full to an empty level of the dispenser. The interior surface also includes a projection oriented opposite the exterior surface and configured to limit a motion of solids within the dispenser. The structure so provided enables the solid, e.g., a frozen liquid, to slide to the heated, bottom portion of the dispenser as liquid is drawn from the dispenser thus providing faster melting.
Abstract:
A method is described for controlling the exhaust temperature of an emission controlling device in the exhaust using both a higher heat loss path and a lower heat loss path along with parallel/sequential turbocharging. The exhaust path is adjusted based on a rate of change of temperature control error.
Abstract:
An exhaust system for an engine having a first set and a second set of cylinders and an emission control device comprising of a first turbocharger coupled to the first set of cylinder(s); a second turbocharger coupled to the second set of cylinder(s); a crossover pipe coupled between and upstream of the first and second turbochargers; a mechanism for adjusting exhaust flow through the crossover pipe; a lower heat loss path coupled between the first turbocharger and the emission control device; and a higher heat loss path coupled between the second turbocharger and the emission control device.
Abstract:
A method and a system for improving conversion efficiency of a urea-based SCR catalyst coupled downstream of a diesel or other lean burn engine is presented. The system includes an electrically heated vaporizer unit into which a mixture of reductant and air in injected. The mixture is vaporized in the unit and introduced into the exhaust gas prior to its entering the SCR catalyst. Introducing the reductant mixed with air into the reductant delivery system prevents lacquering and soot deposits on the heated element housed inside the unit, and also speeds up the vaporization process thus reducing system response delays and improving the device conversion efficiency. The reductant delivery system is further improved by adding a hydrolyzing catalyst to it, and by isolating the reductant and air mixture from the heating element.