Provided is an engine control device for correcting output characteristics of an oxygen sensor and performing air-fuel ratio feedback control. The engine control device includes various sensors for detecting operating state information of an engine, an oxygen sensor, and air-fuel ratio feedback controller to adjust an amount of fuel injected into the engine, on the basis of the operating state information and an output voltage value of the oxygen sensor, wherein the air-fuel ratio feedback controller calculates, in accordance with the operating state information based on detection results from the various sensors, a coefficient for correcting the output voltage value, implements air-fuel ratio feedback control on the basis of an air-fuel ratio feedback control correction amount calculated using a corrected oxygen sensor output voltage value calculated on the basis of the coefficient, and adjusts the amount of fuel injected into the engine.

A fuel injection control unit includes: a first transience determination unit which determines an accelerating state when the first intake pressure differential integration value in a section including a compression stroke, an expansion stroke and an exhaust stroke is greater than a first acceleration determination threshold value; a first transient fuel injection amount calculation unit which calculates an additional fuel injection amount on the basis of the first intake pressure differential integration value; a second transience determination unit which determines an accelerating state when the second intake pressure differential integration value in a section including an intake stroke is greater than a second acceleration determination threshold value which is smaller than the first acceleration determination threshold value; and a second transient fuel injection amount calculation unit which calculates an additional fuel injection amount on the basis of the second intake pressure differential integration value.

The invention relates to a method for controlling a filling level of an exhaust gas component accumulator of a catalytic converter (26) in the exhaust gas of an internal combustion engine (10), in which an actual filling level (.sub.mod) of the exhaust gas component accumulator is determined with a first catalytic converter model (100). The method is characterized in that a lambda setpoint (.sub.in,set) is formed, wherein a predetermined target fill level (.sub.set,flt) is converted into a base lambda setpoint by means of a second system model (104) which is the reverse of the first catalytic converter model (100), a deviation of the actual fill level (.sub.mod) from the predetermined target fill level (.sub.set,flt) is determined and processed to a lambda setpoint correction value by means of a fill level control unit (124), a sum of the base lambda setpoint value and the lambda setpoint value correction value is formed, and said sum is used to form a correction value, with which fuel metering to at least one combustion chamber (20) of the internal combustion engine (10) is influenced.

A method of operating a dedicated-EGR engine includes providing a rich air-fuel mixture to a dedicated cylinder; combusting the rich air-fuel mixture in the dedicated cylinder; modeling the combustion of the rich air-fuel mixture in the dedicated cylinder; estimating the composition of the combustion products in the dedicated cylinder based on interpolation of chemical reaction models of stoichiometric and rich combustion. The method further includes mixing the combustion products from the dedicated cylinder with air to produce an intake mixture; estimating a mass fraction of reformate and a mass fraction of burned gas in the intake mixture; providing the intake mixture to the intake ports of all of the cylinders of the dedicated-EGR engine; combusting an air-fuel mixture in a non-dedicated cylinder of the engine; and controlling an engine control parameter based on the estimated mass fractions of reformate and burned gas in the intake mixture.

A system and an approach for determining various flows in an internal combustion engine, such as an amount of recirculation exhaust gas flow through a controlled valve and a fresh air mass flow to an intake of an engine. Also, among the sensors accommodated in the system, is an inexpensive but slow-responding lambda sensor in the exhaust stream.

The embodiments include: a NOx occlusion/reduction catalyst which is provided to an exhaust passage of an internal combustion engine, occludes NOx in exhaust when the exhaust is in a lean state, and reduces and purifies occluded NOx when the exhaust is in a rich state; a NOx purging control unit which, when the exhaust is in the rich state, executes NOx purging in which the NOx occluded in the NOx occlusion/reduction catalyst is reduced and purified; and a NOx-purging-prohibition processing unit which, when at least one of a plurality of prohibition conditions is fulfilled, prohibits execution of catalyst regeneration processing by the NOx purging control unit even if a catalyst-regeneration-processing start request has been issued, and, when one of the prohibition conditions is fulfilled during execution of the catalyst regeneration processing, invalidates the prohibition condition and allows continued execution of the catalyst regeneration processing by the NOx purging control unit.

A control device is configured to perform, when it is estimated that a combustion fluctuation increases, estimation related to an ignition delay for initial flame generated from a discharge spark and an air-fuel mixture containing fuel spray injected by intake stroke injection. When it is estimated that the ignition delay for the initial flame is increased from that before the increase in the combustion fluctuation, an injection amount in expansion stroke injection is reduced in a next time cycle. When it is estimated that the ignition delay for the initial flame is reduced from that before the increase in the combustion fluctuation, the injection amount in expansion stroke injection is increased in a next time cycle.

A fuel injection amount control device controls a fuel injection amount of an injector in an internal combustion engine including a blow-by gas ventilation system. The fuel injection amount control device includes a reflection rate setting section, a dilution correction section, and a dilution learning section. The reflection rate setting section sets a reflection rate proportional to the amount of a blow-by gas discharged to an intake air. The dilution correction section corrects a fuel injection amount by using, as a correction value, the product obtained by multiplying a reflection rate by a dilution learning value. The dilution learning section updates the dilution learning value such that an air-fuel ratio F/B correction value approaches 0 on the condition that a fuel dilution amount of engine oil is equal to or greater than a predetermined value.

An in-cylinder pressure sensor is provided. It is determined whether a cylinder for which the in-cylinder air-fuel ratio is to be calculated is a rich cylinder or a lean cylinder. A polytropic index in the expansion stroke is calculated from the in-cylinder pressure detected by the in-cylinder pressure sensor. The calculated polytropic index m is corrected based on an operational condition parameter of an internal combustion engine. An in-cylinder air-fuel ratio is calculated based on the corrected polytropic index m in the expansion stroke, the result of the determination of whether the cylinder is a rich cylinder or a lean cylinder, and an m-A/F curve.

Systems and methods for a turbocharged engine comprising an exhaust gas recirculation (EGR) valve and an EGR valve differential pressure sensor disposed in a low pressure EGR (LPEGR) system of the engine and a differential pressure (dP) valve that is distinct from a throttle valve and a dP valve outlet pressure sensor disposed in an induction system of the engine utilize a controller configured to, based on the sensed pressures, determine (i) a modeled pressure at the EGR pickup, (ii) a modeled pressure at outlet of an EGR cooler, (iii) a modeled pressure at an outlet of an air filter and (iv) a modeled pressure at the dP valve outlet, and control the dP valve and the EGR valve based on the modeled EGR pickup pressure, the modeled EGR cooler outlet pressure, the modeled air filter outlet pressure, and the modeled dP valve outlet pressure.