The present invention relates to a catalyst comprising a support substrate having a length L extending between the ends a and b, and four material zones A, B, C and D, wherein material zone B comprises bismuth.

A method for monitoring a gas sensor (14) which comprises two electrochemical measuring cells (20, 30) and which is arranged in an exhaust tract (10) of an internal combustion engine (11), wherein the sensor elements (20, 30) exhibit a substantially identical sensitivity towards a first gas component and a different sensitivity towards a second gas component and are insensitive towards further gas components. In an operating state in which an exhaust gas stream at the gas sensor (14) contains less of the second gas component than of the first gas component a concentration of the first gas component is calculated from each of the sensor signals from the sensor elements (20, 30) and a defect in a sensor element (20, 30) is deduced from the concentrations of the first gas component.

A system (2) comprising (i) a vehicular compression ignition engine (1) comprising one or more engine cylinders and one or more electronically-controlled fuel injectors therefor; (ii) an exhaust line (3) for the engine comprising: a first emissions control device (5) comprising a first honeycomb substrate, which comprises a hydrocarbon adsorbent component; and a second emissions control device (7) comprising an electrically heatable element (7a) and a catalysed second honeycomb substrate (7b), which comprises a rhodium-free platinum group metal (PGM) comprising platinum, wherein the electrically heatable element (7a) is disposed upstream from the catalysed second honeycomb substrate (7b) and wherein both the electrically heatable element (7a) and the catalysed second honeycomb substrate (7b) are disposed downstream from the first honeycomb substrate; a third emissions control device (22), which is a third honeycomb substrate comprising an ammonia-selective catalytic reduction catalyst disposed downstream from the second emissions control device (7); and one or more temperature sensors located: upstream of the electrically heatable element and/or upstream of the first honeycomb substrate; and between the electrically heatable element (7a) and the catalysed second honeycomb substrate (7b); and (iii) an engine control unit (20) comprising a central processing unit pre-programmed, when in use, to control both a heating activation state of the electrically heatable element (7a); an injection timing strategy of the one or more electronically-controlled fuel injector to increase the temperature of at least the first emissions control device following key-on/cold-starting a vehicle comprising the system, wherein the one or more temperature sensors are electrically connected to the engine control unit for feedback control in the system.

A recycling loop configuration of an exhaust gas aftertreatment system decreases a level of system-out NO.sub.x emissions of an engine. An apparatus including the configuration has an exhaust gas recycling system having a closed gas recycling loop system configured to heat gas circulating within the loop, and a blower for circulating gas within the loop. A method for operating the engine includes preheating at least one aftertreatment component of an exhaust gas aftertreatment system of the engine by exposing the component to heated gas circulating in a closed gas recycling loop.

A particulate filter disclosed herein includes a wall-flow structure substrate 10 and a wash coat layer 20 held inside a partition 16 of the substrate 10. The wash coat layer 20 includes an inlet layer 22 formed to have predetermined length L.sub.A and thickness T.sub.A from near an end thereof on an exhaust gas inflow side X1, and an outlet layer 24 formed to have predetermined length L.sub.B and thickness T.sub.B from near an end thereof on an exhaust gas outflow side X2. The inlet layer 22 and the outlet layer 24 partially overlap each other. In the particulate filter disclosed herein, the inlet layer 22 contains a precious metal catalyst, while the outlet layer 24 contains substantially no precious metal catalyst. The length L.sub.A of the inlet layer is 50% or more and 75% or less of a total length L of the partition 16. Thus, the particulate filter is capable of achieving both PM collection performance and pressure-drop reduction performance at high levels.

The disclosure provides a catalyst composition that includes a catalytic material and a magnetic ferrite compound. The magnetic ferrite compound can be pretreated, for example, by heating prior to incorporation within the catalyst composition. The magnetic ferrite compound may include iron, and one or more additional metals including zinc, cobalt, nickel, yttrium, manganese, copper, barium, strontium, scandium, and lanthanum. The disclosure also includes a system and method for heating the catalyst composition, which employs a conductor for receiving current and generating an alternating magnetic field in response thereto.

A vehicle hybrid powertrain includes an internal combustion engine; an electrical drivetrain; a light-off selective catalytic reduction (LO-SCR) device coupled to receive exhaust from the internal combustion engine; and a control system that directs cylinder deactivation (CDA) of the internal combustion engine and controls heat applied to the LO-SCR device.

Methods and systems for improving NOx conversion efficiency of a selective catalytic reduction catalyst are described. In one example, an amount of NH.sub.3 stored in a SCR is adjusted after stopping an engine so that a desired amount of NH.sub.3 may be stored within the SCR when the engine is restarted.

The present invention relates to a selective catalytic reduction (SCR) catalyst comprising a support, vanadium and antimony, a catalytic article comprising the SCR catalyst, and an exhaust treatment system for an internal combustion engine comprising the SCR catalyst. In one embodiment, the invention provides an SCR catalyst for reduction of 5 nitrogen oxides, comprising: a support, and an active material on the support; wherein the support, calculated as its oxide, is present in the SCR catalyst in an amount of 40 to 99% by weight, relative to the total weight of the SCR catalyst; the active material comprises vanadium and antimony; the vanadium, calculated as V.sub.2O.sub.5, is present in the SCR catalyst in an amount of 1 to 15% by weight, relative to the total weight of the SCR catalyst; the 10 antimony, calculated as Sb.sub.2O.sub.3, is present in the SCR catalyst in an amount of 0.5 to 20% by weight, relative to the total weight of the SCR catalyst; wherein the SCR catalyst, after hydrothermally aged at 550° C. for 100 hours with 10% water, has a 200-300° C. denitrification efficiency of at least 60%, with 60,000h.sup.−1 space velocity and an ammonia to NOx molar ratio of 1:11

The disclosure provides methods of preparing small pore zeolites, the method including using a first organic structure-directing agent and a second organic structure-directing agent to crystallize the zeolites, wherein the first organic structure-directing agent is bis-quaternary ammonium cations, and the second organic structure-directing agent is mono-quaternary ammonium cations. Further disclosed are small pore zeolites having a controlled framework aluminum distribution, and selective catalytic reduction catalyst compositions, articles, and systems including such zeolites promoted with a metal.