Abstract: A control system for an internal combustion engine, which controls an output torque of the internal combustion engine for driving a vehicle, is provided. An engine rotational speed is detected, and a change amount of the detected engine rotational speed is calculated. The output torque control amount of the engine is corrected so that the rotational speed change amount coincides with the center value of the local minimum value and the local maximum value of the rotational speed change amount. Specifically, a torque correction amount is calculated according to a torque value which is equal to half of a difference between peak vibration torque values corresponding to the local minimum value and the local maximum value of the rotational speed change amount, and an output torque control amount is corrected with the torque correction amount.

Abstract: A cylinder intake air amount calculating apparatus for an internal combustion engine that calculates a cylinder intake air amount, which is an amount of fresh air sucked in a cylinder of the engine using an intake air pipe model equation which is obtained by modeling an intake pipe of the engine, is provided. An intake air flow rate is obtained. The cylinder intake air amount is calculated by applying the intake air flow rate and a preceding value of the cylinder intake air amount to the intake pipe model equation. A predicted intake air flow rate which is a predicted value of the intake air flow rate is calculated. A predicted cylinder intake air amount which is a predicted value of the cylinder intake air amount is calculated by applying the predicted intake air flow rate and the cylinder intake air amount to the intake pipe model equation.

Abstract: A cylinder intake air amount calculating apparatus for an internal combustion engine for calculating a cylinder intake air amount which is an amount of fresh air sucked into a cylinder of the engine, is provided. An intake air flow rate, which is a flow rate of fresh air passing through an intake air passage of the engine, is obtained, and an intake pressure and an intake air temperature of the engine are detected. A theoretical cylinder intake air amount is calculated based on the intake pressure, the intake air temperature, and a volume of the cylinder. A volumetric efficiency of the engine is calculated by dividing a preceding calculated value of the cylinder intake air amount by the theoretical cylinder intake air amount. The cylinder intake air amount is calculated using the volumetric efficiency, the intake air flow rate, and the preceding calculated value of the cylinder intake air amount.

Abstract: To provide an intake parameter-calculating device and intake parameter-calculating method for an internal combustion engine, which are capable of accurately calculating intake parameters in a case where an intake throttle valve is provided. The intake parameter-calculating device 1 includes an ECU 2. The ECU 2 calculates an error KTHERRCOR using an error model equation (8) (step 2), and calculates a correction coefficient KTHCOR as the reciprocal of the sum of the error KTHERRCOR and 1 (step 3). The ECU 2 calculates a passing air amount GAIRTH by correcting a basic passing air amount GAIRTHN calculated by an equation (11) using a correction coefficient KTHCOR (step 6). A model parameter A for the error model equation (8) is calculated using equations (14) to (18) by onboard identifying calculation with uniform weighting (steps 48 to 53).

Abstract: An atmospheric pressure estimating apparatus which estimates an atmospheric pressure applied to a calculation of control parameters of an internal combustion engine, is provided. An estimated intake air control valve passing air flow rate is calculated based on the estimated atmospheric pressure, the detected intake pressure, and the detected intake air control valve opening. The estimated atmospheric pressure is updated so that the estimated intake air control valve passing air flow rate coincides with the detected intake air control valve passing air flow rate. The estimated intake air control valve passing air flow rate is calculated using the updated estimated atmospheric pressure. The update of the estimated atmospheric pressure and the calculation of the estimated control valve passing air flow rate are sequentially performed. Consequently, the estimated control valve passing air flow rate follows the intake air flow rate, and the estimated atmospheric pressure follows the atmospheric pressure.

Abstract: A control system for an internal combustion engine, which controls an output torque of the internal combustion engine for driving a vehicle, is provided. An engine rotational speed is detected, and a change amount of the detected engine rotational speed is calculated. The output torque control amount of the engine is corrected so that the rotational speed change amount coincides with the center value of the local minimum value and the local maximum value of the rotational speed change amount. Specifically, a torque correction amount is calculated according to a torque value which is equal to half of a difference between peak vibration torque values corresponding to the local minimum value and the local maximum value of the rotational speed change amount, and an output torque control amount is corrected with the torque correction amount.

Abstract: An apparatus determines a cylinder deactivation state of an internal combustion engine capable of deactivating one or more cylinders among a plurality of cylinders in accordance with an instruction from a program-controlled electronic control unit (ECU). The apparatus includes detection means to output a signal corresponding to an intake air amount into the internal combustion engine. The ECU includes Fourier transformation means to perform Fourier transformation on the signal from the detection means at plural fundamental frequencies, and determines the cylinder deactivation state with spectrums obtained from the Fourier transformation means based on predetermined relationship between the spectrums of Fourier transformation at the plural fundamental frequencies and the cylinder deactivation state of the internal combustion engine. The ECU distinguishes a deactivated cylinder with a phase obtained from the Fourier transformation means.

Abstract: To provide an intake parameter-calculating device and intake parameter-calculating method for an internal combustion engine, which are capable of accurately calculating intake parameters in a case where an intake throttle valve is provided. The intake parameter-calculating device 1 includes an ECU 2. The ECU 2 calculates an error KTHERRCOR using an error model equation (8) (step 2), and calculates a correction coefficient KTHCOR as the reciprocal of the sum of the error KTHERRCOR and 1 (step 3). The ECU 2 calculates a passing air amount GAIRTH by correcting a basic passing air amount GAIRTHN calculated by an equation (11) using a correction coefficient KTHCOR (step 6). A model parameter A for the error model equation (8) is calculated using equations (14) to (18) by onboard identifying calculation with uniform weighting (steps 48 to 53).

Abstract: A cylinder intake air amount calculating apparatus for an internal combustion engine for calculating a cylinder intake air amount which is an amount of fresh air sucked into a cylinder of the engine, is provided. An intake air flow rate, which is a flow rate of fresh air passing through an intake air passage of the engine, is obtained, and an intake pressure and an intake air temperature of the engine are detected. A theoretical cylinder intake air amount is calculated based on the intake pressure, the intake air temperature, and a volume of the cylinder. A volumetric efficiency of the engine is calculated by dividing a preceding calculated value of the cylinder intake air amount by the theoretical cylinder intake air amount. The cylinder intake air amount is calculated using the volumetric efficiency, the intake air flow rate, and the preceding calculated value of the cylinder intake air amount.

Abstract: An atmospheric pressure estimating apparatus which estimates an atmospheric pressure applied to a calculation of control parameters of an internal combustion engine, is provided. An estimated intake air control valve passing air flow rate is calculated based on the estimated atmospheric pressure, the detected intake pressure, and the detected intake air control valve opening. The estimated atmospheric pressure is updated so that the estimated intake air control valve passing air flow rate coincides with the detected intake air control valve passing air flow rate. The estimated intake air control valve passing air flow rate is calculated using the updated estimated atmospheric pressure. The update of the estimated atmospheric pressure and the calculation of the estimated control valve passing air flow rate are sequentially performed. Consequently, the estimated control valve passing air flow rate follows the intake air flow rate, and the estimated atmospheric pressure follows the atmospheric pressure.

Abstract: A cylinder intake air amount calculating apparatus for an internal combustion engine is provided. The cylinder intake air amount calculating apparatus calculates a cylinder intake air amount which is an amount of fresh air sucked in a cylinder of the engine using an intake air pipe model equation which is obtained by modeling an intake pipe of the engine. An intake air flow rate which is a flow rate of fresh air passing through the intake pipe of the engine is obtained. The cylinder intake air amount is calculated by applying the intake air flow rate and a preceding value of the cylinder intake air amount to the intake pipe model equation. A predicted intake air flow rate which is a predicted value of the intake air flow rate is calculated. A predicted cylinder intake air amount which is a predicted value of the cylinder intake air amount is calculated by applying the predicted intake air flow rate and the cylinder intake air amount to the intake pipe model equation.

Abstract: An apparatus determines a cylinder deactivation state of an internal combustion engine capable of deactivating one or more cylinders among a plurality of cylinders in accordance with an instruction from a program-controlled electronic control unit (ECU). The apparatus includes detection means to output a signal corresponding to an intake air amount into the internal combustion engine. The ECU includes Fourier transformation means to perform Fourier transformation on the signal from the detection means at plural fundamental frequencies, and determines the cylinder deactivation state with spectrums obtained from the Fourier transformation means based on predetermined relationship between the spectrums of Fourier transformation at the plural fundamental frequencies and the cylinder deactivation state of the internal combustion engine. The ECU distinguishes a deactivated cylinder with a phase obtained from the Fourier transformation means.

Abstract: A fuel control system for an internal combustion engine having an intake passage, a compressor provided in the intake passage, a throttle valve disposed downstream of the compressor, a bypass passage connecting an upstream side of the compressor to a downstream side of the compressor, and an air bypass valve provided in the bypass passage. An intake air flow rate of the engine is calculated based on the engine rotational speed and the intake pressure, which are detected when the air bypass valve is determined to be in the opening operation state. An amount of fuel supplied to the engine is then controlled according to the calculated intake air flow rate.

Abstract: A fuel control system for an internal combustion engine having an intake passage, a compressor provided in the intake passage, a throttle valve disposed downstream of the compressor, a bypass passage connecting an upstream side of the compressor to a downstream side of the compressor, and an air bypass valve provided in the bypass passage. An intake air flow rate of the engine is calculated based on the engine rotational speed and the intake pressure, which are detected when the air bypass valve is determined to be in the opening operation state. An amount of fuel supplied to the engine is then controlled according to the calculated intake air flow rate.

Abstract: A control for controlling an intake air into an engine is provided. A control valve for adjusting an amount of the intake air into the engine is provided. A desired opening degree of a control valve provided in an intake air passage into the engine is determined based on a clogging coefficient. The clogging coefficient indicates a degree of clogging of the intake air passage. An opening degree of the control valve is controlled to converge to the desired opening degree. The clogging coefficient is updated based on a feedback correction amount for feedback controlling a rotational speed of the engine during idling operation. If a leakage in a blow-by gas passage that is connected between the engine and the intake air passage is detected, the update of the clogging coefficient is prohibited.

Abstract: A control for controlling an intake air into an engine is provided. A control valve for adjusting an amount of the intake air into the engine is provided. A desired opening degree of a control valve provided in an intake air passage into the engine is determined based on a clogging coefficient. The clogging coefficient indicates a degree of clogging of the intake air passage. An opening degree of the control valve is controlled to converge to the desired opening degree. The clogging coefficient is updated based on a feedback correction amount for feedback controlling a rotational speed of the engine during idling operation. If a leakage in a blow-by gas passage that is connected between the engine and the intake air passage is detected, the update of the clogging coefficient is prohibited.