Increasing engine idle speed, combined with modulating the timing of the exhaust valve during idling, increases heat transfer from the engine to aftertreatment systems to reduce the time required for the aftertreatment system to reach a minimum temperature for efficient operation. The resultant increases in heat transfer include an increase of at least 30% in the flow rate of exhaust gases and an increase of exhaust temperature by at least 25° C.

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.

Methods and systems are provided for transferring hot, compressed gases from one cylinder to another cylinder while fuel injection in both cylinders is deactivated. In one example, a method may include during a fuel shut-off event, opening a first pre-chamber injector of the first cylinder undergoing late compression or early expansion and opening a second pre-chamber injector of the second cylinder undergoing a late expansion and/or exhaust stroke or undergoing an intake stroke to allow a hot, compressed gas from the first cylinder to transfer to the second cylinder through the first and second pre-chamber injectors.

In a method for operating an internal combustion engine of a motor vehicle, exhaust gas from the internal combustion engine is fed to a particulate filter of the motor vehicle. Until a predetermined filtration rate of the particulate filter is reached, a temporary interruption of a fuel supply to the internal combustion engine is prevented in an overrun mode of the motor vehicle if a temperature of the exhaust gas in the particulate filter is greater than a predetermined threshold value of the temperature. An arrangement of the particulate filter in an exhaust system of the motor vehicle is also described.

An internal combustion engine comprises an engine body, a filter provided in an exhaust passage of the engine body and trapping particulate matter in the exhaust, and a temperature sensor detecting a temperature of gas flowing cut from the filter. A control device controlling this internal combustion engine comprises a fuel cut control pan configured to perform fuel cut control stopping a supply of fuel to a combustion chamber of the engine body and a forced ending part configured to forcibly make the fuel cut control end even if a condition for performance of fuel cut control had stood based on a trend in change of temperature of the gas temperature detected by the temperature sensor.

Approaches for predicting parameters contributing to engine emissions are described. In an example, the values of control parameters may be obtained from the vehicle sensors. Based on the obtained values of the control parameters, estimated emission value may be determined pertaining to a correlation criterion reflecting a predetermined relationship between the obtained control parameter and engine emission. Further, the contribution index of each of the individual control parameters may be identified. Further, based on the estimated emission value and the contribution index, aggregated emission value corresponding to the exhausted emission from the engine for particular trip may be calculated.

A variety of methods and arrangements for controlling the exhaust gas temperature of a lean burn, skip fire controlled internal combustion engine are described. In one aspect, an engine controller includes an aftertreatment system monitor and a firing timing determination unit. The aftertreatment monitor obtains data relating to a temperature of one or more aftertreatment elements, such as a catalytic converter. Based at least partly on this data, the firing timing determination unit generates a firing sequence for operating the engine in a skip fire manner such that the temperature of the aftertreatment element is controlled within its effective operating range.

The present disclosure relates to a method for operating an internal combustion engine (IO). The method includes generating a pressure pulse in an exhaust gas system of the internal combustion engine (IO). The method also includes supplying exhaust gas from a combustion chamber of a cylinder during an exhaust outlet stroke of the cylinder into an inlet channel of the cylinder by propagating the pressure pulse from the exhaust gas system into the combustion chamber of the cylinder. The method further includes supplying the exhaust gas from the inlet channel of the cylinder into the combustion chamber of the cylinder during an intake stroke of the cylinder. By means of internal residual gas control (residual exhaust gas control), the method permits the exhaust gas temperature to be raised in at low load without negatively influencing the full load performance of the internal combustion engine (IO).

When an amount of PM trapped by a GPF is large and a request for regeneration is made, a CPU determines whether an execution condition for executing a temperature increasing process is satisfied. At a point in time t1, at which the execution condition is satisfied, the CPU executes a scavenging process to assign 1 to a condition satisfaction flag Ftr, cause the air-fuel ratio of air-fuel mixture in cylinders #1, #3, and #4 to be the stoichiometric air-fuel ratio, and stop a combustion operation in a cylinder #2. After a point in time t2, which is after a combustion cycle, the CPU executes a temperature increasing process. The temperature increasing process causes the air-fuel ratio of the air-fuel mixture in the cylinders #1, #3, and #4 to be richer than the stoichiometric air-fuel ratio, and stops the combustion operation in the cylinder #2.

Methods and systems are provided for reducing emissions during an engine cold start. In one example, a method may include, during emission control device heating, injecting heated air into an exhaust runner of each cylinder of the engine during an exhaust stroke of the corresponding cylinder, after a blowdown exhaust pulse. In this way, an amount of hydrocarbons in feedgas provided to the emission control device prior to the emission control device reaching its light-off temperature may be reduced.