According to one embodiment, a machine control system includes: a selecting unit which acquires a state quantity of a machine converted from data acquired by a sensor provided in the machine to select two or more learning models according to the acquired state quantity; a composing unit which inputs the state quantity acquired by the selecting unit to each of the two or more learning models selected by the selecting unit to calculate a composed value using a command value output from each of the learning models; and a learning unit which outputs a command value with respect to the machine in a range based on the composed value calculated by the composing unit, acquires a state quantity of the machine, searches for a command value of a specific condition from a combination of the output command value and the acquired state quantity, and outputs the searched command value to the machine, thereby creating a new learning model.

A controller is configured to perform a control process including steps of: setting a learning execution flag to be on when a learning process has not been completed in a present trip, an engine is in a fuel cut state, and a transmission gear position is a second or lower gear position; setting the learning execution flag to be off when the transmission gear position is in a third or higher gear position; controlling to bring the engine into the fuel cut state when the engine is not in the fuel cut state, an accelerator pedal is in an accelerator off state, and the transmission gear position is the second or lower gear position; and setting the learning execution flag to be on.

A method and apparatus for operating an internal combustion engine is disclosed. A signal generated by the oxygen concentration sensor is converted into a first signal indicative of an air/fuel ratio in the engine cylinder. A second signal indicative of an expected air/fuel ratio in the engine cylinder due to a fuel injection is generated and filtered to obtain a filtered signal and used to operate the engine. The filtered signal is obtained by sampling values of the first and second signals. A time constant is calculated based on the sampled values of the first and second signals and a value of the first signal sampled during a preceding control cycle. A value of the filtered signal is calculated based on the calculated time constant, the sampled value of the second signal and a value of the filtered signal calculated during the preceding control cycle.

A controller includes a P/L learning unit that performs P/L learning, a purge learning unit that performs purge learning, an air-fuel ratio learning unit that performs air-fuel ratio learning, and a storage unit that stores learning result. When the learning result of each learning process is not stored in the storage unit at the time of engine start, the P/L learning unit learns an injection characteristic of an in-cylinder injection valve through the P/L learning process whenever the in-cylinder injection valve performs the P/L injection and interrupts the P/L learning process before the P/L learning process is completed. The purge learning unit performs the purge learning process, and the air-fuel ratio learning unit starts the air-fuel ratio learning process provided that the P/L learning process is interrupted. The P/L learning unit then resumes the P/L learning process provided that the purge learning process is completed.

Methods and system for controlling air-fuel ratios in an internal combustion engine are disclosed. One embodiment comprises, adjusting a sensor calibration correction value of an exhaust sensor upstream of a catalyst based on an exhaust sensor downstream of the catalyst. The adjustment of the sensor calibration correction value takes advantage of the fact that certain aromatic hydrocarbons causing errors in the reading of the upstream sensor are not present at the downstream sensor due to sufficient catalytic activity of a catalyst positioned between the sensors.

Methods and systems are provided for monitoring knock in a variable displacement engine. During fuel-cut operation, an engine cylinder may be heated. Upon fuel reactivation, a crankshaft sensor profile may be relearned responsive to lack of knock in the heated cylinder. In this way, erroneous identification of a knocking cylinder due to inaccurate crankshaft position data may be determined and mitigated by re-learning the crankshaft sensor profile.

A method for adapting a characteristic curve of a nitrogen oxide sensor of a combustion engine with exhaust gas recirculation having the first nitrogen oxide sensor upstream of an SCR catalytic converter and a second nitrogen oxide sensor downstream of the SCR catalytic converter includes determining that a particle filter is in a regeneration phase, increasing the exhaust gas recirculation rate, interrupting the supply of urea by a urea injection device, acquiring first nitrogen oxide values from signals generated by the first nitrogen oxide sensor, determining that the first nitrogen oxide values are within a first nitrogen oxide interval, acquiring values from second nitrogen oxide signals generated by the second nitrogen oxide sensor, and determining that the second nitrogen oxide values are within a second nitrogen oxide interval, and adapting the characteristic curve of the first nitrogen oxide sensor by the second nitrogen oxide values.

A method for operating an internal combustion engine with multiple cylinders. Each cylinder of the internal combustion engine includes at least one fuel injector, and each fuel injector is activated for opening and closing via a solenoid valve of the respective fuel injector. Structure-borne sound waves emitted by the fuel injectors and/or accelerations caused by the fuel injectors are detected by measurement. The structure-borne sound waves detected by measurement and/or the accelerations detected by measurement are evaluated, and based on the evaluation, characteristics of the fuel injectors are automatically determined.

A correction device for an air/fuel ratio sensor in the present invention, the sensor issuing an output according to an air/fuel ratio and installed on the downstream from catalyst of the exhaust passage, has air/fuel ratio control means for controlling an air/fuel ratio of an exhaust gas on the upstream side from a catalyst to switch between a rich air/fuel ratio which is richer and a lean air/fuel ratio which is leaner than a stoichiometric air/fuel ratio. Moreover, correction means for correcting an output of the sensor in accordance with a difference between the output of the sensor during a predetermined period during air/fuel ratio control by the air/fuel ratio control means, and a reference output corresponding to a stoichiometric air/fuel ratio, is provided.

The air-fuel ratio feedback control is performed by using a first correction value which is determined depending on a difference between a detected air-fuel ratio (A/F) of an air-fuel mixture and a target A/F and a second correction value which is determined depending on the property of the fuel. Further, fuel property learning control is carried out to correct the first correction value and the second correction value so that an absolute value of the first correction value is not more than a threshold value, when the absolute value of the first correction value is larger than the threshold value after performing the charging with fuel. A combustion continuing correction value range, which is a range of the second correction value to allow the A/F of the mixture to be included in an A/F range in which combustion can be continued, is stored, and the second correction value is set to a value within the combustion continuing correction value range if the A/F feedback control and the fuel property learning control are interrupted.