Abstract:
A method is disclosed of providing a fuel efficient regeneration of an exhaust after-treatment (AT) system that includes a lean oxides of nitrogen (NOX) trap (LNT) and a selective catalytic reduction filter (SCRF) positioned downstream of the LNT. The method includes regulating a selectable position valve. The valve permits a first gas flow portion to pass through the LNT and diverts a remaining second portion of exhaust gas flow from a first passage connecting an engine and the AT system to a second exhaust passage to thereby bypass the LNT. The method also includes regulating a first device to inject fuel into the first portion of the exhaust gas flow. The injection of fuel in to the first portion of the exhaust gas flow provides fuel efficient regeneration of the LNT and promotes NOX conversion and ammonia (NH3) formation in the LNT. A system employing the method is also disclosed.
Abstract:
An engine exhaust system includes an exhaust pipe assembly having an engine exhaust system inlet configured to receive engine exhaust and an engine exhaust system outlet. The system includes a first selective catalytic reduction (SCR) catalyst device positioned downstream in exhaust flow from the engine exhaust system inlet. The first SCR catalyst device includes a substrate with a metallic catalyst coated on the substrate. An electric heater is configured to heat the metallic catalyst. A second SCR catalyst device is positioned downstream in engine exhaust flow from the first SCR catalyst device and upstream of the engine exhaust system outlet. The first SCR catalyst device and the exhaust pipe assembly define an empty chamber between the substrate and the second SCR catalyst device. Engine exhaust flows directly from the substrate to the second SCR catalyst device through the empty chamber.
Abstract:
An exhaust system for a diesel engine, includes an exhaust passage adapted to be attached to the diesel engine. A diesel oxidation catalyst is provided in the exhaust passage along with a selective catalyst reduction device disposed downstream from the diesel oxidation catalyst. A diesel exhaust fluid mixing system includes a diesel exhaust fluid injection nozzle and a mixing device defining a single inlet opening and a single outlet opening connected to one another by a partial spiral flow passage. The diesel exhaust fluid injection nozzle injects diesel exhaust fluid directly into the inlet opening of the partial spiral flow passage.
Abstract:
An after-treatment (AT) system for a flow of exhaust gas of an internal combustion engine includes a first AT device and a second AT device in fluid communication with and positioned in the exhaust gas flow downstream of the first AT device. The AT system also includes an exhaust passage configured to carry the exhaust gas flow from the first AT device to the second AT device. The AT system additionally includes an injector configured to introduce a reductant into the exhaust passage. The second AT device includes an inlet cone having a volute defining a spiral primary path for the exhaust gas flow into the second AT device and configured to generate a swirling motion of and turbulence in the exhaust gas flow. A vehicle employing the AT system is also disclosed.
Abstract:
A direct fuel injection internal combustion engine fluidly coupled to an exhaust aftertreatment system is described and includes a plurality of fluidly coupled exhaust purifying devices and an exhaust gas sensor. A method of controlling the engine includes, activating, via a heater controller, a heating element of the exhaust gas sensor in response to starting the internal combustion engine. An exhaust gas feedstream is monitored to determine a temperature of the exhaust gas sensor. Engine control to effect heating of one of the exhaust purifying devices is permitted only when a temperature of the exhaust gas sensor is greater than a threshold temperature.
Abstract:
A system and method is provided for enhancing the performance of an SCR device, particularly by routinely reducing the amount of reductant deposits accumulated in an exhaust gas system, when the reductant is injected at a reduced temperature. The system may include an engine, an exhaust gas system, an SCR device, an injection device, and a controller configured to execute the present method. The controller may be configured to select an initial injection rate and an initial injection temperature for the reductant; estimate the amount of accumulated reductant deposits present within the exhaust gas system; compare the amount of accumulated reductant deposits to a threshold amount of reductant deposits allowable in the exhaust gas system; and initiate a reductant deposit burn-off mode when the amount of accumulated reductant deposits is greater than the threshold amount of reductant deposits allowable in the exhaust gas system.
Abstract:
A system and method is provided for enhancing the performance of an SCR device, particularly by routinely reducing the amount of reductant deposits accumulated in an exhaust gas system, when the reductant is injected at a reduced temperature. The system may include an engine, an exhaust gas system, an SCR device, an injection device, and a controller configured to execute the present method. The controller may be configured to select an initial injection rate and an initial injection temperature for the reductant; estimate the amount of accumulated reductant deposits present within the exhaust gas system; compare the amount of accumulated reductant deposits to a threshold amount of reductant deposits allowable in the exhaust gas system; and initiate a reductant deposit burn-off mode when the amount of accumulated reductant deposits is greater than the threshold amount of reductant deposits allowable in the exhaust gas system.
Abstract:
An exhaust gas treatment system to treat exhaust gas includes a particulate filter, a second temperature sensor and a control module. The particulate filter includes a PF substrate configured to trap particulate matter contained in the exhaust gas. The second temperature sensor is configured to output an outlet temperature signal indicating an outlet temperature at the outlet of the particulate filter. The control module is in electrical communication with the second temperature sensor to receive the outlet temperature signal. The control module determines a maximum substrate temperature of the PF substrate based on the outlet temperature. The control module is further configured to determine whether the particulate filter includes an active washcoat disposed thereon based on the maximum substrate temperature.
Abstract:
A snorkel assembly for reading optimization of a sensor, wherein the snorkel assembly may be configured to be positioned around and spaced apart from the sensor. The snorkel assembly may include an upstream side and a downstream side. The snorkel assembly may include a cup section and a tube section extending from the cup section. The tube section may include an inlet opening on the upstream side of the snorkel assembly. The cup section may include an exhaust opening on the downstream side of the snorkel assembly.
Abstract:
Selective catalytic reduction filter (SCRF) devices and systems incorporating the same are provided. Systems can include an exhaust gas source, an exhaust gas conduit capable of receiving an exhaust gas stream from the exhaust gas source, and an SCRF device in fluid communication therewith. The SCRF device can include a filter, a selective catalytic reduction (SCR) catalyst disposed on at least portion of the filter, and a soot oxidizing catalyst (SOC) material disposed on at least a portion of one or more of the filter and the SCR catalyst. The SOC material can include one or more transition metal oxides, excluding platinum group metals. The SOC material can include one or more of a titanium oxide, an iron oxide, a tungsten oxide, a cerium oxide, and acidic zirconia. The SOC material can be in amorphous form. The SOC material can be biased towards to the upstream side of the filter.