A method performed by a control unit in connection with a pre-heating process of an aftertreatment system for a combustion engine is provided. The control unit obtains a scheduled start time of the combustion engine. The control unit schedules a pre-heating of the aftertreatment system to be completed before the scheduled start time. The control unit detects a start of the combustion engine at an actual start time. In response to the detected start of the combustion engine, and using the actual and scheduled start times, the control unit determines whether the scheduled pre-heating of the aftertreatment system fulfils one or more success criteria. When the one or more success criteria are fulfilled, the control unit triggers a performance increase of the combustion engine.

In a work machine including an engine; a hydraulic pump; an actuator; an operating member that operates an actuator; an exhaust gas purifying device; a load application device that applies a load to an engine to raise the temperature of exhaust gas; and a control device, the load application device includes a load application valve that is provided in series between the hydraulic pump and the actuator and performs switching as to whether a hydraulic oil flow channel between the hydraulic pump and the actuator is brought into a communication state or a non-communication state in accordance with a control pressure, and if a load application request is input, the control device changes the control pressure exerted on the load application valve on the basis of the presence or absence of input of an operation signal of the operating member.

An exhaust treatment system comprising: a first oxidation catalyst to oxidize nitrogen compounds and/or hydrocarbon compounds in said exhaust stream; a first dosage device downstream of said first oxidation catalyst to supply a first additive into said exhaust stream; a first reduction catalyst device downstream of said first dosage device for reduction of nitrogen oxides in said exhaust stream using said first additive; a particulate filter, comprising a catalytically oxidizing coating downstream of said first reduction catalyst device to catch soot particles and oxidize one or several of nitrogen oxide and incompletely oxidized carbon compounds in said exhaust stream; a second dosage device downstream of said particulate filter to supply a second additive into said exhaust stream; and a second reduction catalyst device downstream of said second dosage device for a reduction of nitrogen oxides in said exhaust stream, using at least one of said first and second additive.

Technical solutions are described for limiting exposure of components of an emissions control system to rich exhaust conditions. An example an emissions control system includes an oxygen storage component; and a controller that limits exposure of the oxygen storage component to rich exhaust conditions. The limiting includes determining an air-to-fuel equivalence ratio in exhaust gas in response to an engine receiving a request to generate torque, the request including a displacement of a pedal; determining an amount of oxygen in the exhaust gas based on the air-to-fuel equivalence ratio; determining an oxygen level stored by the oxygen storage component; and if the oxygen level is above a predetermined threshold, lowering a torque generation rate of the engine, which specifies amount of torque generated per unit displacement of the pedal.

A catalyst activation method and a catalyst activation device are provided which can activate a NOx catalyst efficiently in an ensured fashion. A plurality of accessories are connected to an internal combustion engine, and a control mechanism is provided on each of the accessories for controlling a load to be exerted on the internal combustion engine by driving the corresponding accessory. Then, a temperature of a NOx catalyst is acquired, and when the acquired temperature of the NOx catalyst is lower than a catalyst activation temperature, in order to drive additionally a certain number of accessories in the plurality of accessories which correspond to the temperature difference, the controlling mechanism(s) which corresponds to the accessory(ies) to be driven additionally is controlled to drive the corresponding accessory(ies) so as to increase a load to be exerted on the internal combustion engine.

Methods and systems are provided for HP-EGR and LP-EGR. In one example, a method includes selecting a HP-EGR mode or a LP-EGR mode in response to a first difference calculated between ammonia desired during the two modes, and a second difference calculated between NO.sub.x emitted during the two modes.

The disclosure is intended to oxidize PM deposited in a filter in a suitable manner. Provision is made for a filter of wall flow type, a temperature raising unit to raise the temperature of the filter from a downstream side thereof, an exhaust gas shut-off valve, and a controller. The controller controls a flow of exhaust gas in the filter by once fully closing the exhaust gas shut-off valve and then fully opening it when the flow rate of the exhaust gas is equal to or larger than a predetermined flow rate, so as to cause PM to move to a downstream side portion in the filter in the direction of flow of exhaust gas, and carries out regeneration processing which oxidizes the PM by using the temperature raising unit after the controller has caused the PM to move to the downstream side portion of the filter.

Methods and systems are provided for accurately inferring an exhaust temperature during steady-state and transient vehicle operation based on the duty cycle of an exhaust gas sensor heating element. A steady-state temperature is inferred based on an inverse of the duty cycle, and then adjusted with a transfer function that compensates for transients resulting from changes in vehicle speed, and load, and for the occurrence of tip-in and tip-out events. The inferred temperature can also be compared to a modeled temperature to identify exhaust temperature overheating conditions, so that mitigating actions can be promptly performed.

A method for catalyst purge control may include the steps of: performing, by a catalyst purge electronic control unit (ECU), catalyst purge control based on engine temperature; calculating an estimated engine temperature the catalyst purge ECU when fuel-cut is completed, and controlling, by the catalyst purge ECU, an amount of purge fuel injected by an injector based on the estimated engine temperature for the catalyst purge control.

The invention relates to a method and to a motor vehicle for diagnosing an exhaust gas catalytic converter (28), which is arranged in an exhaust gas tract (20) of an internal combustion engine (12) and is suitable for converting at least one exhaust gas component, wherein the exhaust gas tract (20) has an exhaust gas sensor (48) arranged upstream of the exhaust gas catalytic converter (28) and has an exhaust gas recirculation system (38), which is designed to remove at least part of the exhaust gas from an exhaust gas duct (24) of the exhaust gas tract (20) downstream of the exhaust gas catalytic converter (28) and to feed the removed exhaust gas to the internal combustion engine (12). The method comprises the following steps: measuring a first concentration (NOX1) of the exhaust gas component upstream of the exhaust gas catalytic converter (28) by means of the exhaust gas sensor (48) during fueled operation of the internal combustion engine (12), recirculating at least part of the exhaust gas by means of the exhaust gas recirculation system (38) during unfueled overrun of the internal combustion engine (12), measuring a second concentration (NOX2) of the exhaust gas component by means of the exhaust gas sensor (48) during the unfueled overrun of the internal combustion engine (12), and determining a state of the exhaust gas catalytic converter (28) in dependence on the first and second concentrations (NOX1, NOX2) of the exhaust gas component.