A method for operating an exhaust-gas purification system which is arranged in the exhaust system of an internal combustion engine, and an exhaust-gas purification system, are described. In the method, a combination of electrical catalytic converter heating measures with internal combustion engine catalytic converter heating measures is implemented, whereby particularly fast and inexpensive heating of a catalytic converter is achieved. The corresponding exhaust system preferably has, in an exhaust-gas flow direction, firstly a support catalytic converter and then a heated catalytic converter.

A catalyst article for treating exhaust gas comprising: a substrate comprising an inlet end, an outlet end with an axial length L; a first catalytic region beginning at the inlet end and extending for less than the axial length L, wherein the first catalytic region comprises a first platinum group metal (PGM) component, a first inorganic oxide, and an optional first oxygen storage capacity (OSC) material; a second catalytic region beginning at the outlet end and extending for less than the axial length L, wherein the second catalytic region comprises a second PGM component, an optional second inorganic oxide, and a second OSC material; and a third catalytic region; wherein the weight ratio of the first inorganic oxide to the optional first OSC material is greater than 1:1.

Subject of the invention is an exhaust gas purification system for a gasoline engine, comprising in consecutive order the following devices: a first three-way-catalyst (TWC1), a gasoline particulate filter (GPF) and a second three-way-catalyst (TWC2), wherein the platinum-group metal concentration (PGM) of the TWC2 is greater than the PGM of the GPF, wherein the PGM is determined in g/ft3 of the volume of the device.

The invention also relates to methods in which the system is used and uses of the system.

A method includes receiving information indicative of a temperature of exhaust gas emitted from an engine operating at an engine speed, determining that the temperature of the exhaust gas is below a predefined temperature threshold, determining an engine load sized to increase the temperature of the exhaust gas above the predefined temperature threshold, increasing a load on the engine to the determined engine load while maintaining the engine at the engine speed by increasing at least one of a fuel flow rate and a fuel flow pressure of the fuel pump powered by the engine, and diverting the excess fuel from the fuel flow path upstream of the engine. Increasing at least one of the fuel flow rate and the fuel pressure of the fuel pump causes excess fuel to be provided to the engine than is necessary to maintain the engine at the engine speed.

An internal combustion engine emissions reduction system in which a emissions passing through a second catalyst element having a second catalyst function are mixed with emissions passing through a first catalyst element having a first catalyst function.

The present invention relates to a composition comprising platinum supported on titanium oxide, the platinum particles having an average particle diameter of 50-200 nm. The composition has a surprisingly low light-off temperature for the ammonia oxidation and a high selectivity for oxidation to N2.

An internal combustion engine has an exhaust gas aftertreatment system comprising in the given order in the flow direction of the exhaust gas: a device for metering ammonia and/or a compound that can be decomposed to form ammonia into the exhaust gas to be cleaned, as a reducing agent; one or more SCR catalysts, which form a first SCR unit; one or more SCR and/or ammonia oxidation and/or ammonia slip catalysts, which form a second SCR unit; and a NO.sub.x sensor in the exhaust gas tail pipe. An amount, to be metered into the exhaust gas, of ammonia and/or of the decomposable compound is set using the nitrogen oxide concentration in the exhaust gas tail pipe that is determined by the NO.sub.x sensor, and the occurrence or non-occurrence of an ammonia excess in the region of the NO.sub.x sensor can be determined from the sensor signal of the NO.sub.x sensor by evaluating said sensor signal.

A method for exhaust gas post treatment is provided, comprising the following steps: a) providing a nitrogen oxide-containing raw exhaust gas, b) introducing the nitrogen oxide-containing raw exhaust gas into a catalytic evaporator (1), c) introducing a fuel into the catalytic evaporator (1), whereby a converted fuel is obtained, d) mixing urea with the converted fuel, and e) feeding the mixture obtained after step d) into an exhaust gas post treatment system (8). Alternatively or in addition, a device may be provided for exhaust gas post treatment.

Subject of the invention is an exhaust gas purification system for a gasoline engine, comprising in consecutive order the following devices: a first three-way-catalyst (TWC1), a gasoline particulate filter (GPF) and a second three-way-catalyst (TWC2), wherein the wash coat load (WCL) of the TWC2 is greater than the WCL of the GPF, wherein the WCL is determined in g/l of the volume of the device. The invention also relates to methods in which the system is used and uses of the system.

A method for operating an exhaust-gas purification system which is arranged in the exhaust system of an internal combustion engine, and an exhaust-gas purification system, are described. In the method, a combination of electrical catalytic converter heating measures with internal combustion engine catalytic converter heating measures is implemented, whereby particularly fast and inexpensive heating of a catalytic converter is achieved. The corresponding exhaust system preferably has, in an exhaust-gas flow direction, firstly a support catalytic converter and then a heated catalytic converter.