A filter retentate analysis system and method is disclosed, which provides information to diagnose the current and historical state of a system generating the retentate or through which the retentate has passed. The disclosure describes the analysis of retentate characteristics which may include the composition, amount, distribution, and physical or chemical properties of the retentate useful to monitor or diagnose the state, health, or operating history of a system or sub-system. The analysis is broadly applicable to wide range of systems and process ranging from engines and exhaust systems to production plants and equipment.

A system includes an exhaust aftertreatment system including a particulate filter and a controller. The controller is configured to: receive information comprising a temperature regarding a filter of the aftertreatment system; and responsive to determining that the temperature regarding the filter is below a temperature threshold, command the engine to operate according to a first firing fraction. The first firing fraction may define a number of active cylinders of the engine relative to a total number of cylinders of the engine, and correspond to a predetermined temperature value of the filter.

An engine system includes a compression ignition diesel engine connected with an aftertreatment system. A source of diesel fuel, which may have a high sulfur content, is fluidly connected to the engine. The aftertreatment system includes a particle trap fluidly positioned between the engine and the tailpipe, and an SCR catalyst fluidly positioned on the particle trap or between the particle trap and the engine. The SCR catalyst is a sulfur tolerant SCR catalyst. A non-thermal particle trap regeneration system includes a valve fluidly positioned between a particulate volume and an inlet to the particle trap. A reductant system has a doser positioned, possibly in the exhaust manifold, to deliver a reductant into the aftertreatment system upstream from the SCR catalyst.

Method for removal of soot, ash and metals or metal compounds, together with removal of NOx and SOx being present in process off-gasses or engine exhaust gasses.

Methods and systems are provided for cleaning an exhaust particulate filter by routing air via the exhaust particulate filter during a vehicle-off condition. In one example, during vehicle-off conditions, a turbocharger may be reverse rotated via an electric motor or an engine may be reverse rotated via an electric machine to route air via the exhaust particulate filter and the soot collected from the particulate filter may then be deposited on an air filter coupled to the intake manifold. During a subsequent engine start, the soot from the intake air filter may be routed to the engine cylinders for combustion.

Methods and systems are provided for regenerating and purging a particulate filter of an exhaust treatment system for a combustion engine. In one example, a method may include flowing exhaust gas in a reverse direction through the particulate filter to purge particulate matter to an intake manifold of the engine for combusting. The duration of purging may be based on a regeneration achieved during a previous regeneration of the particulate filter during a deceleration fuel shut-off event.

Method and system for removal of particles such as soot, ash and heavy metals, and optionally additionally NO.sub.X and SO.sub.X being present in exhaust gas from an engine or process equipment.

Methods and systems are provided for cleaning an exhaust particulate filter by routing air via the exhaust particulate filter during a vehicle-off condition. In one example, during vehicle-off conditions, a turbocharger may be reverse rotated via an electric motor or an engine may be reverse rotated via an electric machine to route air via the exhaust particulate filter and the soot collected from the particulate filter may then be deposited on an air filter coupled to the intake manifold. During a subsequent engine start, the soot from the intake air filter may be routed to the engine cylinders for combustion.

The purpose of the present invention is to provide an exhaust purifier (1) which is capable of restoring a pressure difference (P) and a purification rate (NOx removal efficiency) of a NOx catalyst (14) to the initial states thereof. An exhaust purifier (1) for removing particulate matter adhered to a NOx catalyst (14) by injecting pressurized air using an air injection nozzle (16) into a housing (13) of a catalyst reactor (12) in which the NOx catalyst (14) serving as a catalyst is positioned, wherein the particulate matter is removed by increasing the pressure inside the catalyst reactor (12) to a prescribed pressure (IP) within a prescribed interval of time (t) by operating an injection valve (17) for supplying pressurized air.

A method for operating an exhaust gas purification system connected to an internal combustion engine of a motor vehicle is disclosed. The purification system includes an SCR catalyst for catalyzed reaction of nitrogen oxides contained in the exhaust gas of the internal combustion engine with ammonia. The method includes adding a reducing agent containing ammonia to the exhaust gas upstream of the SCR catalyst at a predeterminable dosage rate and determining a pressure value correlating with an absolute pressure in the exhaust gas purification system on the input side of the SCR catalyst. The dosage rate is specified at least as a function of the pressure value.