The subject matter of this specification can be embodied in, among other things, an engine system that includes an intake manifold configured to receive and convey air to a combustion chamber, an intake valve upstream of the intake manifold and configured to regulate an air flow into the intake manifold, an exhaust manifold configured to receive combustion products from the combustion chamber, a recirculation flow passage configured to convey exhaust gasses from the exhaust manifold to the intake manifold, a recirculation flow control valve configured to regulate gas flow through the recirculation flow passage, and a controller configured to determine that the engine system is in a motoring condition, open, during the motoring condition and based the determining, the recirculation flow control valve, and close, during the motoring condition and based the determining, the intake valve.

Methods, systems, and devices for operating an internal combustion engine at a firing fraction that is less than a value of 1.0, wherein one or more cylinders of the internal combustion engine are not designated to be fired, determining a smoothing event time period where a particular one of the cylinders that have not been designated to be fired is either skipped or recharged, selecting a periodic disruptive waveform to approximate that is related to a skip or recharge event that is part of the smoothing event time period, determining a first harmonic sinusoid from a group of harmonic sinusoids that reduces the error between an approximated waveform and the disruptive waveform, determining a timeframe for utilizing the first harmonic, and actuating an additional motor to initiate a supplemental quantity of torque during the smoothing event time period based on the disruption quantity of torque.

A method of determining an operational status of an exhaust gas recirculation valve of an internal combustion engine arrangement, the EGR valve being configured to control a flow of combusted exhaust gas from an exhaust manifold to an inlet manifold of the ICE arrangement. The method comprising controlling the EGR valve to transition from a closed position; obtaining a signal indicative of a variation of temperature level of the gas present in the inlet manifold at a duration between a first point in time and a second point in time when the EGR valve assumes the open position; determining, based on the signal indicative of the variation of the temperature level, a velocity value indicative of a maximum increase in change of temperature level during the time period between the first point in time and the second point in time; comparing the velocity value with a predetermined threshold; and determining that the EGR valve is operational when the velocity value is higher than the predetermined threshold.

A method comprises determining that an aftertreatment system is in a cold-operation mode; initiating a low engine-out NOx (LEON) mode by controlling a component of a vehicle containing the aftertreatment system to decrease an instantaneous engine out NOx (EONOx) amount and to increase exhaust energy relative to a normal operation mode for an engine of the vehicle; receiving information indicative of an operating status of the vehicle during the LEON mode; disengaging the LEON mode; subsequent to disengaging the LEON mode, initiating a thermal management (TM) mode for the aftertreatment system, wherein the TM mode is initiated by controlling a component of the vehicle to increase fueling to the engine for a power level by reducing engine efficiency and directing excess fuel to the aftertreatment system; receiving information indicative of an operating status of the vehicle during the TM mode; and disengaging the TM mode.

Provided are a method and an ICE system, including an internal combustion engine including a first and a second set of cylinders. A first and a second EGR valve control flow of exhaust gas from the cylinders to an EGR conduit. A controller controls the closing of the second EGR valve, thereby preventing flow of exhaust gas from the second set of cylinders to the EGR conduit. The second EGR valve is upstream of a turbine. The controller is configured to activate a fuel injector for late post injection of fuel into the second set of cylinders when the second EGR valve is closed, so that at least a part of the fuel that exits the second set of cylinders is uncombusted. An exhaust gas aftertreatment system receives and treats exhaust gas which is not recirculated in the EGR conduit, and includes an oxidation catalyst for combustion.

The invention relates to a method for operating an internal combustion engine system (2), wherein the internal combustion engine system (2) is provided with an air intake duct (3), an exhaust gas duct (4) and an exhaust gas recirculation (EGR) system (5), wherein the EGR system (5) comprises an EGR conduit (6) that fluidly connects the exhaust duct (4) and the intake duct (3), and wherein a gas feeding device (7) configured to feed exhaust gas from the exhaust duct (4) to the intake duct (3) is arranged in the EGR conduit (6). The method is characterized in that it comprises the step of: detecting an indication of accumulated deposits of soot, hydrocarbons or other contaminants in the gas feeding device (7) by determining whether a rotational friction of a rotary member (71, 72) of the gas feeding device (7) exceeds a threshold value. The invention also relates to an internal combustion engine system (2) configured for being operated by such a method and to a vehicle (1) provided with such an engine system (2). The invention further relates to means for controlling the above method.

Methods and/or systems for operating an exhaust-gas aftertreatment system of an internal combustion engine include: setting the internal combustion engine to a diagnostic operating mode with relevant diagnostic operating parameters of the internal combustion engine are set to correspond with diagnostic default values; inducing a targeted, defined NH.sub.3 and/or NO.sub.X concentration change upstream of the filter; measuring the NH.sub.3 and/or NO.sub.X concentration change downstream of the filter; providing a correlating concentration comparison value; evaluating the concentration change on the basis of the respective concentration comparison value and predefined limit values; and diagnosing the SCR particle filter as defective if the evaluation yields that the concentration comparison value has overshot a predefined limit value.

The invention relates to a method for operating an internal combustion engine system (2), wherein the internal combustion engine system (2) is provided with an air intake duct (3), an exhaust gas duct (4) and an exhaust gas recirculation (EGR) system (5), wherein the EGR system (5) comprises an EGR conduit (6) that fluidly connects the exhaust duct (4) and the intake duct (3), and wherein a gas feeding device (7) configured to feed exhaust gas from the exhaust duct (4) to the intake duct (3) is arranged in the EGR conduit (6). The method is characterized in that it comprises the step of: providing a flushing liquid in the EGR conduit (6) upstream of the EGR gas feeding device (7) so as to flush and clean the EGR gas feeding device (7). The invention also relates to an internal combustion engine system (2) configured for being operated by such a method and to a vehicle (1) provided with such an engine system (2). The invention further relates to means for controlling the above method.

Systems and methods are described for performing a diagnostic on an exhaust gas aftertreatment system. A gas entry parameter into a portion of an exhaust system of an engine is determined. In response to determining that the gas entry parameter is less than the predetermined threshold, a level of NH3 in the exhaust gas is determined. In response to determining that the level of NH3 is above a threshold value, degradation of a particulate filter of the exhaust gas aftertreatment system is indicated.

A method is disclosed for controlling a compression release brake mechanism in a combustion engine. The method comprises: determining a desired exhaust manifold gas pressure level; continuously monitoring a set of control parameters, including at least two of cylinder pressure, exhaust manifold pressure, turbine speed and turbine expansion ratio; controlling a brake pressure valve and a variable turbine geometry by said control parameters, to drive one of the control parameters to a set first maximum level; and, while maintaining the first of the set of control parameters at the set first maximum level, controlling an exhaust gas recirculation valve by said control parameters in a closed loop to allow exhaust gas to recirculate towards an air inlet system while driving a second of the set of control parameters to a set second maximum level.