Methods and systems for operating an engine with a pump that is driven via the engine are described. In one example, start of opening of an injector that supplies a fluid to an engine exhaust system is timed based on a period of the pump so that the output of the fluid injector may be repeatable in the presence of fluid pressure oscillations that are periodic with pump rotation.

The present disclosure describes methods for operating an EAS including a close coupled SCR unit, a downstream SCR unit, a diesel oxidation catalyst unit (DOC) and a diesel particulate filter (DPF). The methods utilize the close coupled SCR unit to manage NOx emissions from the EAS during regeneration of a diesel particulate filter (DPF).

Provided is an exhaust gas purification apparatus having a control device that monitors the transition of a detection value of each of an upstream NOx sensor and a downstream NOx sensor, and when the NOx purification rate of the SCR catalyst falls to a value of a first threshold or lower, generates an abnormality detection signal indicating that an over storage state has occurred in an SCR catalyst if the amount of change in the detection value of the upstream NOx sensor per unit time is at least a second threshold and the amount of change in the detection value of the downstream NOx sensor per unit time is at most a third threshold.

Methods and systems are provided for an aftertreatment system. In one example, a method comprises regenerating a NO.sub.x trap during an engine shut-down event. The method further comprises reversing a direction of flow of a gas through a HP-EGR passage during the regenerating.

A spray bar injector including a spray bar defining a longitudinal axis and including a fluid inlet and a plurality of spray outlet orifices spaced apart longitudinally in a direction along the longitudinal axis. A check or spray valve is operatively connected to each spray outlet orifice. A master valve is in fluid communication with the fluid inlet, operatively connected to divert flow from the fluid inlet into a first passage and block flow into a second passage in a first position to open the check valves and issue a spray from the spray outlet orifices, and to divert flow from the fluid inlet into the second passage and block flow into the first passage in a second position to close the check valves and block issue of spray from the spray outlet orifices.

An exhaust aftertreatment arrangement for cleaning exhaust gases includes a fluid channel for providing a fluid pathway for the exhaust gases, a selective catalyst reduction, SCR, catalyst, arranged in or downstream the fluid channel, a heating arrangement for heating the exhaust gases, the heating arrangement being arranged upstream of the SCR catalyst and comprising an electrical heating element, a first fluid pathway for guiding the exhaust gases to the electrical heating element, and a second fluid pathway for guiding the exhaust gases to bypass the electrical heating element, wherein the heating arrangement is removably arranged relative the fluid channel.

System (1) for the purification of exhaust gases (S) of an endothermic engine (100), comprising at least one duct (2) for exhausting the gases produced by said endothermic engine, means (3) for cooling said exhaust gases which cross said duct (2) so that to cause, at least in part, the condensation of the water vapor contained in said exhaust gases in water (AC), and means (4) for separating the condensed water (AC), which is condensed by said cooling means along the exhaust duct, from the exhaust gases and for deviating it along a secondary duct (10), said system being characterized by further comprising filtering means (5), which are arranged downstream of said separating means (4) along said secondary duct (10), for filtering said condensed and separated water (AC).

An aftertreatment system for a diesel engine may include a diesel particulate filter configured for placement in fluid communication with the diesel engine to receive an exhaust flow. The system may also include a selective catalytic reduction system configured for arrangement downstream of the diesel particulate filter and a NO.sub.x sensor configured to measure a NO.sub.x concentration in the exhaust flow entering the selective catalytic reduction system. The system may also include a controller configured to estimate a ratio of NO.sub.2 to NO.sub.x downstream of the diesel particulate filter and based on a factor affecting the generation of NO.sub.2 upstream of the selective catalytic reduction system. The controller may also be configured to adjust the measured NO.sub.x concentration based on the ratio to provide an estimated actual NO.sub.x concentration and dose diesel exhaust fuel into the exhaust flow based on the estimated actual NO.sub.x concentration.

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 disclosure is directed towards a filter arrangement for a reductant supply system of a selective catalytic reduction system. The reductant supply system comprises a tank and a suction tube mounted at least partially in the tank for receiving reductant liquid from the tank. The filter arrangement comprises a restraining body, a filter at least partially forming a filter chamber, a filter outlet from the filter chamber formed through the restraining body and/or filter and a filter mount mounted to the restraining body and/or filter. The restraining body extends radially outwardly from the filter mount and is configured to restrain the filter such that, under the effect of buoyancy in the tank in use, gas in the filter chamber is directed towards the filter outlet.