Methods and systems are provided for controlling operating of a split exhaust engine system including a scavenge exhaust gas recirculation system based on a composition of constituents within a total flow through the scavenge exhaust gas recirculation system. In one example, a method may include adjusting an engine operating parameter in response to individual flows of each of burnt gases, fresh air, and fuel to an intake passage, upstream of a compressor, from a scavenge manifold coupled to scavenge exhaust valves, the individual flows of each of the burnt gases, fresh air, and fuel determined based on a valve opening overlap between the scavenge exhaust valves and intake valves of the engine.

An exhaust gas analyzer to analyze exhaust gas discharged from an internal combustion engine includes an infrared light source, a photodetector, a CO.sub.2 concentration calculation part and an O.sub.2 concentration calculation part. The infrared light source irradiates infrared light to the exhaust gas. The photodetector detects infrared light after passing through the exhaust gas. The CO.sub.2 concentration calculation part calculates a CO.sub.2 concentration in the exhaust gas on the basis of a detection signal obtained by the photodetector. The O.sub.2 concentration calculation part calculates an O.sub.2 concentration in the exhaust gas from the CO.sub.2 concentration by using a fuel combustion reaction equation and an EGR rate in an exhaust gas recirculation system or a value related to the EGR rate.

A control system for a compression ignition engine includes a combustion chamber, a throttle valve, an injector, an ignition plug, an EGR system, a sensor device and a controller. The controller includes a first mode module, a second mode module and a changing module configured to change an engine mode from a first mode to a second mode in response to a change demand. The changing module outputs signals to the throttle valve and the injector in response to the demand so that an air-fuel ratio of mixture gas becomes a stoichiometric air-fuel ratio or a substantially stoichiometric air-fuel ratio, and outputs a signal to the EGR system so that an EGR gas amount decreases more than before the demand, and when the EGR gas amount is determined to be decreased to a given amount, the changing module permits that the second mode module starts the second mode.

Methods and systems are provided for a comprex charger. In one example, a comprex charger is integrally arranged with an electric machine and shares a cooling arrangement therewith.

A method and apparatus for controlling part load mode engine torque are provided. The method includes setting a limitation of part load mode engine torque based on a current traveling environment and calculating a first engine torque variation in the basis of state information of a battery. When the first engine torque variation is calculated, a second engine torque variation is calculated based on a measured engine error amount. The limitation of part load mode engine torque is compensated based on the calculated first and second engine torque variations.

An object of the present invention is to predict change of a combustion limit due to cycle variation of temperature and an EGR ratio and perform correction every cycle to decrease an amount of combustion consumption. Therefore, in an internal combustion engine control device that controls an internal combustion engine including a cylinder and an exhaust pipe, the internal combustion engine control device includes a control unit configured to perform EGR control of controlling an exhaust gas in the exhaust pipe to return to an inner cylinder of the cylinder, obtain temperature of the gas in the internal cylinder and an EGR ratio in a state where both an intake valve and an exhaust valve are closed in an combustion cycle, and correct a combustion parameter in a same combustion cycle as the combustion cycle on the basis of the obtained gas temperature and the obtained EGR ratio.

A system for control of the air path of an internal combustion engine including a feed-forward controller and a feed-back controller. The feed-forward controller configured to in a sampling period, obtain model parameter values, incorporate the modeled parameter values and reference values into an optimization for a nonlinear model predictive control, perform a Newton method iteration of the optimization in order to determine a solution, and issue commands that control inputs for engine operation based on the solution. The feed-back controller configured to obtain modeled parameter values, obtain measured parameter values based on the operating condition of the engine, incorporate the modeled parameter values, measured parameter values, and reference values into an optimization for a nonlinear model predictive control, perform a Newton method iteration of the optimization in order to determine a solution, and issue commands that control inputs for engine operation based on the solution.

An abnormality detection device for an air-fuel ratio sensor is provided. An air-fuel ratio sensor is provided in an exhaust passage. A storage device stores mapping data specifying a mapping. The mapping outputs an abnormality determination variable using first time series data and second time series data as an input. The first time series data is time series data of an excess amount variable in a first predetermined period. The excess amount variable is a variable corresponding to an excess amount of fuel actually discharged to the exhaust passage in relation to an amount of fuel reacting without excess or deficiency with oxygen contained in a fluid discharged to the exhaust passage. The second time series data is time series data of an air-fuel ratio detection variable in a second predetermined period.

A method for determining the mass m of air trapped in each cylinder of an internal combustion engine comprises determining, a value for each quantity of a first group of reference quantities comprising at least intake pressure P measured inside the intake manifold, engine rotation speed n, mass of gases produced by the combustion in the previous operating cycle (OFF) and present in the cylinder, determining, the actual inner volume V of each cylinder as a function of the engine rotation speed n, of the lift H of the intake valve and of the closing delay angle IVC of the intake valve, and determining the mass m of air trapped in each cylinder as a function of the first group of reference quantities and of the actual volume V inside each cylinder, on the basis of the aforesaid quantities P, V, OFF.

The exhaust purification system of an internal combustion engine has: exhaust purification catalysts 20, 24 arranged in an exhaust passage and able to store oxygen; and a control device 31 for calculating an EGR rate of intake gas supplied to combustion chambers 5 and for controlling an air-fuel ratio of the exhaust gas flowing into the catalysts. The control device alternately switches the air-fuel ratio between a rich air-fuel ratio and a lean air-fuel ratio, and controls the air-fuel ratio so that the air-fuel ratio is switched from the lean air-fuel ratio to the rich air-fuel ratio when the oxygen storage amount of the catalyst is greater, when the calculated EGR rate is relatively high, compared to when it is relatively low.