A method for operating a motor vehicle having an engine and an electric machine, a transmission, a battery, and an exhaust treatment system having a particulate filter. The battery discharges during a charge-depleting mode of the electrical machine and charges when the electrical machine operates as a generator such that the battery charge state moves between lower and upper limits. If a filter regeneration requirement is detected, the filter is regenerated by raising the temperature of the exhaust gas. When the need for filter regeneration is detected, the battery is discharged to below the lower limit, in the charge-depleting mode of the electrical machine, prior to the regeneration. Subsequently, to regenerate the filter, the engine is operated to raise the exhaust gas temperature by increasing the torque provided by the engine, and the electric machine operates as a generator to charge the battery and/or operate an auxiliary electrical load.

An exhaust treatment system and method for the treatment of an exhaust stream from a combustion engine are provided. A first oxidation of compounds comprising one or more of nitrogen, carbon and hydrogen in the exhaust stream is carried out by a first oxidation catalyst. Further, a value (NO2_1/NOx_1)det for a ratio between a first amount of nitrogen dioxide and a first amount of nitrogen oxides leaving said first oxidation catalyst is determined. Active control of at least one parameter related to the combustion engine is carried out, based on the determined value, so that the ratio is impacted. A first additive is supplied into the exhaust stream, following which a first reduction of the first amount of nitrogen oxides is carried out through a catalytic reaction in a catalytic filter, which consists of a particulate filter with an at least partly catalytic coating with reduction characteristics. The catalytic filter is arranged for catching and oxidizing of soot particles, and to carry out the first reduction of the first amount of nitrogen oxides using the first additive.

A vehicle includes an internal combustion engine including an exhaust passage, a catalyst provided in the exhaust passage, and an electronic control unit. When the engine stop condition is established, the electronic control unit stops fuel injection and increases a catalyst inflow oxygen amount that is an amount of oxygen flowing into the catalyst by a specified oxygen increase amount. The engine stop condition is a condition for stopping operation of the internal combustion engine. The specified oxygen increase amount is larger than an increased part of the catalyst inflow oxygen amount that is increased by the stop of the fuel injection.

A controller for an engine includes processing circuitry configured to perform fuel cut-off for regenerating the filter by burning fine particulate matter collected in the filter. The processing circuitry is configured to perform an interruption process for interrupting the fuel cut-off in a case in which warming of the passenger compartment is requested when the fuel cut-off is being performed and an engine coolant temperature, which is a temperature of the engine coolant, becomes lower than or equal to a predetermined temperature after the fuel cut-off is started.

A device for reducing total hydrocarbon (THC) contained in exhaust gas in a CNG-diesel dual fuel engine system, includes: an engine providing power for the diesel and outputting exhaust gas due to operation; a MOC (Methane Oxidation Catalyst) oxidizing and discharging CH.sub.4 contained in exhaust gas discharged from the engine; an exhaust valve disposed in a pipe connecting the rear end of the engine and the front end of the MOC, and discharging the exhaust gas produced by the engine; a first temperature sensor disposed at the front end of the exhaust valve and measuring the temperature of exhaust gas coming from the engine; a second temperature sensor disposed at the rear end of the exhaust valve and measuring the exhaust gas discharged from the exhaust valve and flowing into the MOC; and an exhaust valve control unit increasing the temperature of exhaust gas flowing into the MOC.

In a method for heating an exhaust system of a combustion engine of a motor vehicle, the exhaust system comprises at least two components for exhaust gas cleaning. For at least one component, a temperature regulation is provided for heating the component while using a heating operation mode. For the heating of the exhaust system, a heating operation is used via a pulse control with heating pulses (101) and heating pauses (102), which switches between a heating operation mode and a normal operation without heating measures.

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.

A system of controlling an engine includes: an engine including a combustion chamber, an intake valve, an ignition switch, and an exhaust valve; a dual continuously variable valve duration device to adjust an intake duration of the intake valve and an exhaust duration of the exhaust valve; and a controller for adjusting an ignition timing of the ignition switch, the intake duration, and the exhaust duration based on a driving condition of the vehicle. In particular, until the temperature of the exhaust gas reaches a predetermined temperature after the engine starts, the controller sets the ignition timing to an ignition timing within a predetermined ignition timing range, sets the intake duration of the intake valve to an intake duration within a predetermined intake duration range, and increases the exhaust duration of the exhaust valve to a limit exhaust duration according to the set intake duration.

A system of controlling an engine provided with a dual continuously variable valve duration device may include an engine, an intake valve for selectively supplying air or a mixture of the air and fuel to the combustion chamber, an ignition switch to ignite a burner to burn the mixture, and an exhaust valve disposed in the combustion chamber to selectively discharge exhaust gas in the combustion chamber to an outside of the combustion chamber, the dual continuously variable valve duration device provided to adjust an intake duration of the intake valve and an exhaust duration of the exhaust valve, a warm-up catalytic converter including a three-way catalyst for purifying hydrocarbons, carbon monoxide, nitrogen oxides contained in the exhaust gas downstream of the engine, and a controller for adjusting an ignition timing, the intake duration and the exhaust duration of the ignition switch based on a driving condition of a vehicle.

A method for performing a regeneration cycle for regenerating a diesel particulate filter of a transport refrigeration system. The method includes increasing an air intake throttling level of an engine intake air flow by reducing an air control valve area. The method also includes supplementing the temperature increase of the air intake throttling by energizing an engine preheater.