An exhaust system includes a first exhaust after-treatment system receiving exhaust gases generated by an engine, a second exhaust after-treatment system downstream of the first exhaust after-treatment system, and at least one bypass connecting an engine outlet to an inlet to the second exhaust after-treatment system. A turbocharger is associated with the bypass and a bypass valve is located upstream of the turbocharger. The bypass valve is moveable between an open position to bypass exhaust gas flow to the first exhaust after-treatment system, a closed position to direct all exhaust gas flow to the first exhaust after-treatment system, and a partially open position where one portion of exhaust gas flow is directed into the first exhaust after-treatment system and a remaining portion of exhaust gas flow is directed into the turbocharger. A controller controls movement of the bypass valve between the open, closed, and partially open positions.

Methods and systems are provided for extending a duration of engine idle-stop while reducing a frequency of engine restart from idle-stop. In one example, in response to engine restart conditions where combustion torque is not necessary, an engine can be rotated electrically, without fuel delivery, via an electric motor. The unfueled engine spinning via the motor drives an FEAD which in turns drives an actuator coupled to the FEAD, such as an AC compressor or an automatic transmission oil pump.

An apparatus and method for improving warm-up of a catalytic aftertreatment device is disclosed in which the flow to a catalyst brick is controlled using a flow control device so as to restrict the flow of exhaust gas to only a central core of the catalyst brick when rapid heating of the catalyst brick is desired to reach a light-off temperature and to otherwise allow the flow of exhaust gas to the entire front face of the catalyst brick. By restricting the area of the catalyst brick to which exhaust gas can flow the energy density of the exhaust gas flowing to the central core is higher than it is when there is no restriction of flow thereby reducing the time needed to warm-up the catalyst brick to a minimum light-off temperature.

An exhaust purification system includes an electrochemical reactor provided in an engine exhaust passage; a bypass passage bypassing the electrochemical reactor; a flow control valve controlling an amount of exhaust gas, discharged from an engine body, flowing into the electrochemical reactor and the bypass passage; and a control device controlling the flow control valve. The electrochemical reactor includes a holding material holding NO.sub.X or HC and is configured so as to purify NO.sub.X or HC held at the holding material if encrgized. The control device controls the flow control valve so as to control the amount of exhaust gas flowing into the electrochemical reactor so that a temperature of the electrochemical reactor is maintained at less than a desorption start temperature where NO.sub.X or HC starts to be desorbed from the holding material.

An internal combustion engine system includes a cylinder block with a plurality of cylinders, a gas intake manifold for providing at least air to the cylinder block and an exhaust gas manifold for exiting the exhaust gas from the cylinder block, wherein the exhaust gas manifold includes at least a main exhaust gas outlet and a waste gate exhaust gas outlet, wherein the main exhaust gas outlet is connected to a main exhaust gas pipe for guiding the exhaust gas to a main exhaust gas after treatment system and the waste gate exhaust gas outlet is connected to a waste gate exhaust gas pipe, and wherein the waste gate exhaust gas pipe is reconnected to the main exhaust gas pipe upstream of the main exhaust gas after treatment system and includes at least one waste gate exhaust gas after treatment unit, such as an oxidation catalyst such as a diesel oxidation catalyst, for catalytically treating the exhaust gas streaming through the waste gate exhaust gas pipe, and to a method for increasing the temperature in an internal combustion engine system.

An exhaust gas receiver 21 is provided between an expanded passage portion 132 of an upstream connection member 13 and a catalyst end surface 111. The exhaust gas receiver 21 extends along the entire circumference of a catalyst accommodation case 12. The exhaust gas receiver 21 extends from an upstream opening end portion 121 of the catalyst accommodation case 12 toward an inner part of the passage of the expanded passage portion 132 such that the exhaust gas receiver 21 separates from the expanded passage portion 132, and a space 211 is defined between the exhaust gas receiver 21 and the catalyst end surface 111. Flows of bypass exhaust gas hitting against the catalyst end surface 111 and bouncing off the catalyst end surface 111 hit against and are received by the exhaust gas receiver 21.

Methods and systems are provided for a close-coupled aftertreatment device. In one arrangement, a system may include an engine comprising separate first and second overall exhaust lines, where a blow-off line branches off of the second overall exhaust line, and where the close-coupled aftertreatment device is arranged in the blow-off line and configured to receive exhaust gases during at least a cold-start of the engine.

An exhaust system for an internal combustion engine, especially diesel internal combustion engine, includes an exhaust gas flow duct (12). At least one exhaust gas treatment unit (23, 26, 28, 30) is provided in an exhaust gas treatment duct area (16) of the exhaust gas flow duct (12). The exhaust gas treatment duct area (16) of the exhaust gas flow duct (12) extends, in at least some areas, in an insulation volume (20), through which exhaust gas discharged from the exhaust gas treatment duct area (16) can flow.

Method and system for the removal of nitrogen oxides, volatile organic compounds and particulate matter from engine exhaust gasat cold start conditions.

The present disclosure relates to a combustion engine system and a method of operation thereof. The combustion engine system includes a pollutant conversion system and an exhaust gas turbocharger that includes a variable turbine geometry and a waste gate valve. The variable turbine geometry includes adjustable guide elements surrounding the turbine wheel in a circumferential direction and are arranged to define an overall cross-section in their respective position for the exhaust gas. In a control mode where the pollutant conversion system comprises a temperature above a threshold temperature, the guide elements are adjusted such that the overall cross-section is between a control minimum value and a control maximum value. In a heat-up mode at temperatures of the pollutant conversion system below the threshold temperature, the guide elements are moved to a heat-up position where the overall cross-section is smaller than the control minimum value.