A method of regenerating a lean NOx trap (LNT) of an exhaust purification system provided with the LNT and a selective catalytic reduction (SCR) catalyst may include: determining whether a regeneration release condition of the LNT is satisfied; determining whether a regeneration demand condition of the LNT is satisfied; and performing regeneration of the LNT if the regeneration release condition of the LNT and the regeneration demand condition of the LNT are satisfied. In particular, the regeneration release condition of the LNT is satisfied if all of an engine operating condition, an LNT state condition, and a lambda sensor synchronization condition are satisfied.

A work vehicle having a plurality of working modes allowing working in accordance with a load state includes an engine, an exhaust gas purification apparatus, a reducing agent tank, a state determination portion, and an engine control unit. The exhaust gas purification apparatus purifies a nitrogen oxide in an exhaust gas. The reducing agent tank stores a reducing agent. The state determination portion determines a state of the reducing agent. The engine control unit controls output of the engine with the use of a restricted-operation engine output torque curve in which horsepower output from the engine is lower than horsepower output from the engine at the time when each of the plurality of working modes is selected, when a state of the reducing agent is equal to or lower than a reference value.

The invention relates to a control method that allows the mean quantity of nitrogen oxides per kilometer covered emitted by a vehicle fitted with an internal combustion engine associated with a post-treatment system to be kept below a predefined fixed threshold, for any journey made by the vehicle. The mean quantity emitted over a fixed elementary distance that has just been covered by the vehicle is calculated iteratively, together with a long-term conformity factor which is equal to the mean quantity emitted over the entire distance covered since the start of the journey. When it is found that the long-term conformity factor is above the threshold, the engine and/or the post-treatment system is regulated in such a way as to obtain, over the next fixed elementary distance, a mean quantity of nitrogen oxides per kilometer that is lower than the threshold value FC, for example equal to 90% of the threshold, whatever the engine operating point. Thus, the long-term conformity factor converges towards the threshold.

The present disclosure relates to a control unit (8) for controlling reactivation of a lean NOx trap (LNT) disposed in an exhaust system (3) connected to an internal combustion engine (2), the control unit (8). The control unit (8) has at least one processor (11) configured to generate a reactivate flag (RF) for the LNT (6). A memory device (12) having instructions stored therein is coupled to the at least one processor (11). The at least one processor (11) is configured to generate the reactivate flag (RF) when the exhaust gas supplied to the LNT (6) is lean and an LNT temperature (T.sub.LNT) is greater than or equal to a predefined LNT temperature threshold (T1). The present disclosure also relates to a method of controlling reactivation of the LNT (6). The present disclosure also relates to a vehicle comprising reactivation control apparatus.

Methods and systems are provided for a NO.sub.x sensor. In one example, a method includes heating a NO.sub.x sensor during a vehicle off in response to a cumulative heat energy applied to the NO.sub.x.

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.

The invention relates to a method to heat exhaust gases to a selected specific temperature by fuel injection control in an internal combustion engine (112), which engine comprises a control unit (115) registering the currently requested load and determining a required fuel amount in response to the requested load. The method involves registering low load operation of the internal combustion engine; registering an input from at least one exhaust after-treatment system (121) sensor indicating a detected condition; determining an exhaust temperature requirement for the detected condition and calculating a target exhaust temperature; selecting a group of cylinders to be regulated for achieving the target exhaust temperature; calculating a ratio for desired 1.sup.st and 2.sup.nd fuel amounts to be injected alternately in consecutive induction strokes for the selected group of cylinders to achieve the target exhaust temperature; wherein the ratio defines an offset between an increased 1.sup.st fuel amount to be injected in a cylinder of the selected group of cylinders for every second induction stroke, and a reduced 2.sup.nd fuel amount to be injected for the intermediate induction strokes.

A control system for a vehicle, the control system having one or more controllers, the control system being arranged to: determine a likelihood of a NOx adsorber trap of a vehicle requiring purging; determine an efficiency of purging the NOx adsorber trap; determine an operating efficiency of a selective catalyst reduction system of the vehicle; determine a schedule for purging of the NOx adsorber trap of the vehicle in dependence on the likelihood of the NOx adsorber trap requiring purging, the efficiency of purging the NOx adsorber trap, and the operating efficiency of the selective catalyst reduction system; and control purging of the NOx adsorber trap according to the schedule.

The invention relates to an internal combustion engine system (100), comprising: —an internal combustion engine (2) comprising a cylinder block (3) housing a plurality of cylinders (4), a first intake manifold (6a) connected to a first group of cylinders (4a) a second distinct intake manifold (6b) connected to a second group of cylinders (4b) and a first, respectively a second, exhaust manifold (8a, 8b) for receiving the exhaust gas emitted from the first, respectively the second, group of cylinders (4a, 4b); —an air inlet line (10); —an EGR line (20) connected to the first and second exhaust manifolds (8a, 8b); wherein the internal combustion engine system is operable in at least two operating modes, respectively a normal operating mode in which all cylinders are supplied with fuel and a regeneration operating mode, in which the cylinders of the first group of cylinders (4a) are no longer supplied with fuel, characterized in that: —the system also includes a mixing unit (30) comprising a four-way valve, said four-way valve (30) having a first inlet (31) connected to the EGR line (20), a second inlet (32) connected to the air inlet line (10), a first outlet (33) connected to the first intake manifold (6a) and a second outlet (34) connected to the second intake manifold (6b); —the four-way valve is designed so that, in said normal operating mode, the intake gases supplied to the first intake manifold (6a) and to the second intake manifold (6b) have approximately the same proportion of exhaust gas and so that, in said regeneration operating mode, the intake gas supplied to the first intake manifold (6a) only includes exhaust gas.

A method of two-step variable valve lift (VVL) operation learning control for a vehicle may include: applying, by a lift controller, a VVL control to an electric two-step VVL system; determining, by the lift controller, whether the vehicle is running in an electric vehicle (EV) mode; and when the vehicle is running in the EV mode, performing, by the lift controller, a learning time securing control of allowing a VVL operation learning to be performed by engine operating for an operation avoidance area and an operation avoidance time which are applied to a secondary lift of an exhaust valve.