A method for predicting urea crystal build-up in an engine system when operating according to an intended drive cycle. The method includes providing data representing engine operational conditions for the internal combustion engine during the intended drive cycle, wherein the data comprises values for at least engine speed and engine torque distributed over a time period representing the intended drive cycle; determining values and time variation for at least one exhaust parameter during the time period of the intended drive cycle when the engine system is operated according to the engine operational condition data; providing a reference relation between values and time variation for the at least one exhaust parameter and an expected urea crystal build-up in the engine system when operating the engine system at different engine operational conditions, predicting urea crystal build-up in the engine system when operating according to the intended drive cycle by comparing the determined values and time variation for the at least one exhaust parameter with the reference relation.

A method for predicting soot build-up in an engine system when operating according to an intended drive cycle. The engine system includes an internal combustion engine and an exhaust gas aftertreatment system provided with a particulate filter. The method includes providing data representing engine operational conditions for the internal combustion engine during the intended drive cycle, wherein the data comprises values for at least engine speed and engine torque distributed over a time period representing the intended drive cycle; determining a working temperature for the exhaust gas aftertreatment system during the intended drive cycle based on the data representing the engine operational conditions; providing a reference relation between working temperature of the exhaust gas aftertreatment system and a corresponding estimated magnitude of a build-up of soot in the exhaust gas aftertreatment system; and predicting soot build-up in the engine system when operating according to the intended drive cycle by comparing the determined working temperature for the exhaust gas aftertreatment system with the reference relation.

A maintenance system includes a processing circuit that executes a calculation process for calculating recommended execution time of a regeneration process. The processing circuit of the maintenance system also executes a display process for displaying the calculated recommended execution time. The processing circuit executes an analysis process for analyzing a usage mode of a vehicle based on history information of travel data. The processing circuit refers to an analysis result of the analysis process in the calculation process. When the analysis result of the analysis process indicates a usage mode in which overaccumulation is unlikely to recur, the processing circuit calculates the recommended execution time shorter than when the analysis result does not indicate the usage mode in which the overaccumulation is unlikely to recur.

A catalytic converter system having oxygen storage materials is disclosed and methods for determining whether to reactivate oxygen storage materials and monitoring failure events of the oxygen storage materials are also disclosed.

Engine systems and methods use a dual air injection approach to control exhaust reactions and to maintain temperatures below a maximum limit of exhaust system components during engine enrichment operation conditions. Dual air injectors are disposed in the exhaust system with one upstream from, and another downstream from, the catalytic converter. Providing air injection before and/or after the converter helps convert all HC, CO, and PM emissions while keeping the catalyst temperature below the catalyst protection temperature limit. Air injection quantity may be controlled and diagnosed by monitoring the temperatures before and after the catalytic converter. The catalytic converter may be a three-way catalytic converter for lower cost or a downstream two-way catalytic converter may be added if further emission reduction is necessary.

An apparatus for a gas turbine power plant that uniquely configures emission control equipment such that the plant can extend the emissions compliant operational range, the apparatus including a plurality of oxidation (CO) catalysts arranged in series.

A system includes an exhaust aftertreatment system in exhaust gas receiving communication with an engine including a plurality of cylinders where the engine is structured to operate according to low load conditions and where a controller is structured to determine that at least one diesel emissions fluid (DEF) doser is frozen based on at least one of an ambient air temperature and a DEF source temperature. The controller is structured to operate the engine according to a skip-fire mode in response to a DEF flag indicating that the at least one DEF doser is frozen. The skip-fire mode comprises firing a portion of the plurality of cylinders that is less than a total amount of cylinders of the plurality of cylinders. The controller is structured to discontinue the skip-fire mode in response to determining that the at least one DEF doser is likely thawed.

Systems and methods for controlling a gasoline urea selective catalytic reductant catalyst are described. In one example, an observer is provided that corrects an estimate of an amount of NH.sub.3 that is stored in a SCR. The amount of NH.sub.3 that is stored in the SCR is a basis for generating additional NH.sub.3 or ceasing generation of NH.sub.3.

Systems and methods for operating a hybrid vehicle are presented. In one example, electric current may be supplied to or withheld from a positive temperature coefficient (PTC) heater and an electrically heated catalyst. In particular, electric current may be delivered to the PTC heater and withheld from the electrically heated catalyst, or vice-versa, in response to a catalyst temperature and battery state of charge.

A method (200) for operating an exhaust gas burner (120) in an exhaust section (102) of an internal combustion engine (110), comprising introducing a purging fluid comprising at least air (20) into the exhaust gas burner (120) during a purging operating phase (205), which lies outside the time of a normal operating phase (201) of the exhaust gas burner (120), and discharging a discharge mixture formed using the purging fluid from the exhaust gas burner (120), wherein the exhaust gas burner (120) is operated for the purpose of heating a component (130, 150) of the exhaust section (102) to its operating temperature during the normal operating phase (201). A processor unit (140) and a computer program for carrying out such a method (200) are furthermore proposed.