A method of compensating for fuel injection deviations of injectors includes: in a case of a low flow rate operating range, learning cylinder-specific lambda deviations regarding cylinder-specific engine roughness deviations using a characteristic map defining a relationship between engine roughness deviations and lambda deviations; calculating cylinder-specific amounts of injection compensation necessary to remove the cylinder-specific lambda deviations; and compensating for amounts of injection of injectors a by adding the cylinder-specific amounts of injection compensation to cylinder-specific target amounts of injection.

A means of detecting the in-situ fuel-to-air-ratio (FAR) in a combustor or flame zone using a Fourier-based flame ionization probe is presented. The use of multiple excitation frequencies and its detection at certain frequencies or combinations of harmonics of those excitation frequencies, namely, the inter-modulation distortion, provides a novel means of extracting a high signal-to-noise ratio (SNR) FAR measurement in a combustor.

A method to detect and mitigate sensor or actuator degradation in an automobile system includes: collecting a signal data output from at least one device which is outputting the signal data in response to monitored operational parameters of a motor vehicle system; analyzing patterns of the signal data compared to a signal data output from a nominal operating one of the at least one device using an artificial intelligence program; and identifying when the patterns of the signal data exceed a threshold level indicating the at least one sensor or actuator is operating in a degraded condition.

Methods and systems are provided for accurately estimating intake aircharge based on the output of an intake oxygen sensor while flowing EGR, purge, or PCV hydrocarbons to the engine. The unadjusted aircharge estimate is used for engine fuel control while the hydrocarbon adjusted aircharge estimate is used for engine torque control. A controller is configured to sample the oxygen sensor at even increments in a time domain, stamp the sampled data in a crank angle domain, store the sampled data in a buffer, and then select one or more data samples corresponding to a last firing period from the buffer for estimating the intake aircharge.

A method is presented for regulating a filling of an exhaust gas component reservoir of a catalytic converter in the exhaust of an internal combustion engine. Using a first catalytic converter model, an actual fill level of the exhaust gas component reservoir is ascertained. An aging state of the catalytic converter is determined; and a set of model parameters of the first catalytic converter model is allocated to the aging state; the individual model parameters being ascertained by interpolation from basic values of model parameters, the basic values having been determined for at least two different aging states of a catalytic converter of identical design.

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 method for controlling a filling level of an exhaust gas component accumulator of a catalytic converter in the exhaust gas of an internal combustion engine where an actual filling level of the accumulator is determined with a first catalytic converter model. The method includes forming a lambda setpoint is formed, wherein a predetermined target fill level is converted into a base lambda setpoint via a second system model reverse of the first catalytic converter model, a deviation of the actual fill level from the predetermined target fill level is determined and processed to a lambda setpoint correction value via a fill level control unit, 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 of the internal combustion engine is influenced.

A method of purifying exhaust gas discharged from an engine using a three-way catalyst may include: calculating, by a controller, an oxygen mass flow rate flowing into the three-way catalyst based on an air-fuel ratio and an exhaust gas flow rate measured by a front oxygen sensor arranged at a front end of the three-way catalyst; calculating, by the controller, an oxygen storage capacity (OSC) and an oxygen storage amount (OSA) of the three-way catalyst by integrating the oxygen mass flow rate; correcting, by the controller, the calculated oxygen storage amount based on an actual voltage measurement value of the exhaust gas measured by a rear oxygen sensor arranged at a rear end of the three-way catalyst; and controlling, by the controller, a control variable related to performance of the three-way catalyst based on the corrected oxygen storage amount and the oxygen storage capacity.

A fuel passage leads a fuel from a pressure-accumulation vessel to a nozzle hole of a fuel injection valve. A fuel pressure sensor detects a fuel pressure in a fuel passage. An estimation device is applicable to a combustion system, which includes these components, and includes a mixing acquisition unit and an injection amount estimation unit. The mixing acquisition unit acquires the mixing ratio of various components contained in the fuel used for combustion in the internal combustion engine. The injection amount estimation unit estimates an injection amount of the fuel from the nozzle hole according to a change mode of the fuel pressure, which is detected with the fuel pressure sensor and associated with injection of the fuel from a nozzle hole, and the mixing ratio acquired with the mixing acquisition unit.

A method for operating an engine system including an internal combustion engine and an exhaust gas aftertreatment device, including: carrying out a fill level control to control a fill level of the exhaust gas aftertreatment device as a function of a predefined fill level setpoint value; operating a pilot control for the fill level control; and adapting the pilot control as a function of a deviation between a measured lambda value and a modeled lambda value.