A method for evaluating a sensor signal of an exhaust NOx sensor, which is disposed downstream of a three-way catalytic converter in an exhaust system of a spark ignition internal combustion engine. An ammonia factor is modeled downstream of the three-way catalytic converter using an ammonia formation model. A NOx emission is modeled in the exhaust system downstream of the three-way catalytic converter using a NOx model. The modeled ammonia emissions and the modeled NOx emission are separated by a separation algorithm using the sensor signal of the exhaust NOx sensor. The separation algorithm provides quantitative information about the tailpipe ammonia emissions and the tailpipe NOx emissions of the spark ignition internal combustion engine. An engine control unit and an internal combustion engine for carrying out such a method are also provided.

Methods and systems are provided for determining condition of an air filter coupled to an intake passage of an engine system. In one example, a method may include estimating a resistance of the air filter based on a manifold air charge value. The manifold air charge value may be either a mass air flow or a manifold air pressure.

A monitoring system and method for detecting clogging through fouling of an air filter (3) of an internal combustion engine (5) comprising a differential pressure sensor means (7) for determining a differential pressure between an ambient environment and a position directly downstream of the air inlet filter. The system further comprising at least one exhaust flow sensor means (9) for determining the exhaust flow, and a controller (13) which is communicatively connected to each of the sensor means for processing information therefrom. The controller is arranged for determining a first filter resistance coefficient based on, at least, a measurement of the differential pressure, and the exhaust flow. The system is arranged for, using the controller, to calculate a second filter coefficient based on the historic evolution of the first filter coefficient, the controller further arranged for comparing the second filter coefficient to a boundary value, and generating a clogging alarm signal when the second filter coefficient exceeds said boundary value.

Systems and methods of controlling operation of a vehicle engine are provided. For instance, one example aspect of the present disclosure is directed to determining a spark timing associated with a combustion engine. For instance, a combustion phasing target to be implemented by a combustion engine can be received. A spark timing associated with the combustion engine can be determined based at least in part on the combustion phasing target. The spark timing can be determined based at least in part on an optimization comprising one or more iterations determined during an engine cycle. The spark timing is determined based at least in part on a combustion phasing prediction model determined based at least in part on at least one of laminar flame speed, residual gas mass, or turbulent intensity.

In one embodiment, a method includes receiving, via a first sensor, a signal representative of at least one of a manifold pressure, a manifold temperature, or a manifold mass flow rate of a manifold. The method further includes deriving, via a manifold model and the first sensor signal, a gas concentration measurement at a first manifold section of the manifold. The method additionally includes applying the gas concentration measurement during operations of an engine, wherein the manifold is fluidly coupled to the engine.

A system includes a controller that has a processor configured to receive a first signal from a first oxygen sensor indicative of a first oxygen measurement, wherein the first oxygen sensor is disposed upstream of a catalytic converter system; and to receive a second signal from a second oxygen sensor indicative of a second oxygen measurement, wherein the second oxygen sensor is disposed downstream of the catalytic converter system; and to execute a catalyst estimator system, wherein the catalyst estimator system is configured to derive an oxygen storage estimate based on the first signal, the second signal, and a catalytic converter model. The processor is configured to derive a system oxygen storage setpoint for the catalytic converter system based on the catalytic converter model and the oxygen storage estimate.

In one embodiment, a method includes receiving, via a first sensor, a signal representative of at least one of a manifold pressure, a manifold temperature, or a manifold mass flow rate of a manifold. The method further includes deriving, via a manifold model and the first sensor signal, a gas concentration measurement at a first manifold section of the manifold. The method additionally includes applying the gas concentration measurement during operations of an engine, wherein the manifold is fluidly coupled to the engine.

A method for evaluating a sensor signal of an exhaust NOx sensor, which is disposed downstream of a three-way catalytic converter in an exhaust system of a spark ignition internal combustion engine. An ammonia factor is modeled downstream of the three-way catalytic converter using an ammonia formation model. A NOx emission is modeled in the exhaust system downstream of the three-way catalytic converter using a NOx model. The modeled ammonia emissions and the modeled NOx emission are separated by a separation algorithm using the sensor signal of the exhaust NOx sensor. The separation algorithm provides quantitative information about the tailpipe ammonia emissions and the tailpipe NOx emissions of the spark ignition internal combustion engine. An engine control unit and an internal combustion engine for carrying out such a method are also provided.

To reduce regular combustion variations across combustion cycles, an engine control apparatus includes: an engine that has cylinders inside of which gas exchange is performed by opening and closing an intake valve and an exhaust valve for each cylinder, and that is operated by causing a plurality of the cylinders to sequentially execute combustion cycles; a combustion control device that is attached to the engine, and controls combustion in each of the plurality of cylinders; and a controller that controls the operation of the engine by outputting a control signal to the device, wherein the controller, before combustion in each of the plurality of cylinders, estimates state quantities of the cylinder based on a plant model of the engine which indicates regular combustion variations across the combustion cycles, and outputs to the combustion control device the control signal, which has been corrected based on the estimated state quantities.