Abstract: A knock determination apparatus for an internal combustion engine calculates a knock intensity based on an output signal of an in-cylinder pressure sensor in a gate range for knock determination. When the calculated knock intensity is larger than a knock determination threshold value, the knock determination apparatus determines that knock has occurred. Further, the knock determination apparatus calculates an integrated intensity which is an integrated value of knock intensities that are equal to or larger than a knock intensity at a point of 97% or more in a target knock level among knock intensities that are calculated at the respective cycles during continuous N cycles in the same cylinder. Furthermore, the knock determination apparatus corrects a knock determination threshold value so that the difference between the calculated integrated intensity and a target integrated intensity becomes small.

Abstract: This internal combustion engine is provided with a variable compression ratio mechanism capable of changing a mechanical compression ratio by changing the volume of the combustion chamber at the top dead center. The pressure and temperature of remaining combusted gas within the combustion chamber at the time when the exhaust valve is closed in the intake stroke is measured or estimated, the pressure and temperature of intake air supplied into the combustion chamber after the exhaust valve is closed in the intake stroke is measured or estimated, and based on the assumption that the pressure and temperature of the remaining combusted gas which saturates the volume of the combustion chamber at the time when the exhaust valve is closed in the air intake stroke become, when the intake air is supplied to the combustion chamber, equal to the pressure and temperature of the intake air, the volume of the remaining combusted gas after the change is calculated.

Abstract: An engine is provided with an ECU for executing engine control by using various control parameters. The ECU includes a learning map storing a learning value of the control parameter and executes weighting learning control of the learning value. In the weighting learning control, each time the control parameter is acquired, a weight wkij decreasing larger if a distance from a position of an acquired value zk of the control parameter to a grid point is larger is set to each of the grid points of the learning map. Then, on the basis of the acquired value zk of the control parameter and the weight wkij, the learning values Zij(k) at all the grid points are updated. As a result, all the learning values can be efficiently updated in one session of the learning operation.

Abstract: A control apparatus for an internal combustion engine is configured to: calculate measured data of MFB in synchrony with crank angle based on in-cylinder pressure detected by an in-cylinder pressure sensor; execute engine control based on a measured value of a specified fraction combustion point that is calculated based on the measured data of MFB; calculate a first correlation index value for MFB and a second correlation index value for dMFB/d?; and suspend the engine control when the first correlation index value is less than a first determination value and the second correlation index value is greater than or equal to a second determination value.

Abstract: A reciprocating internal combustion engine includes an in-cylinder pressure sensor and a crank angle sensor. Data of calculated heat release amount in synchronization with crank angle is calculated using in-cylinder pressure after absolute pressure correction. An amount of heat release amount variation is calculated as a difference between a first calculated heat release amount at a first crank angle on an advanced side of TDC and a second calculated heat release amount at a second crank angle symmetrical about TDC. An actual heat release amount is estimated based on the amount of heat release amount variation calculated using, as the first crank angle, a crank angle on an advanced side of a combustion start point and using, as the second crank angle, a crank angle on a retarded side of a combustion end point.

Abstract: A controller for an internal combustion engine includes a crank angle detector and an ECU. The ECU is configured to: (a) calculate a mass fraction burned; (b) acquire the crank angle, which is detected by the crank angle detector when the mass fraction burned reaches a predetermined mass fraction burned, as a specified crank angle; and (c) control at least one of an amount of fuel injected, an amount of intake air, or ignition energy on the basis of a first difference. The first difference is a difference between a first parameter and a second parameter. The first parameter is a crank angle period from an ignition time to the specified crank angle or a correlation value of the crank angle period. The second parameter is a target value of the crank angle period or a target value of the correlation value.

Abstract: A control apparatus for an internal combustion engine includes an in-cylinder pressure sensor for detecting an in-cylinder pressure. In-cylinder heat release amount data is calculated based on in-cylinder pressure data synchronized with the crank angle that is sampled using the in-cylinder pressure sensor. If the number of items of the heat release amount data that are located in a combustion period identified using the heat release amount data is two or more, the control apparatus determines that the in-cylinder pressure data that is sampled in synchronization with the crank angle is reliable and the engine can be controlled accordingly.

Abstract: A knock determination apparatus for an internal combustion engine calculates a knock intensity based on an output signal of an in-cylinder pressure sensor in a gate range for knock determination. When the calculated knock intensity is larger than a knock determination threshold value, the knock determination apparatus determines that knock has occurred. Further, the knock determination apparatus calculates an integrated intensity which is an integrated value of knock intensities that are equal to or larger than a knock intensity at a point of 97% or more in a target knock level among knock intensities that are calculated at the respective cycles during continuous N cycles in the same cylinder. Furthermore, the knock determination apparatus corrects a knock determination threshold value so that the difference between the calculated integrated intensity and a target integrated intensity becomes small.

Abstract: An object of this invention is to appropriately control the valve timing (VT) even in a case where a plurality of local maximum points or local minimum points exist on a characteristic line representing a relation between the VT and an air amount. An engine 10 includes VVTs 42 and 44 and the like. When a predetermined operation condition that a plurality of local maximum points exist on a load characteristic line representing a relation between the VT of an intake valve 32 and a load KL is established, an ECU 60 first calculates the VT corresponding to a maximum value KLmax of the load KL as a maximum air amount VT (VTmax). Subsequently, if the maximum value KLmax of the load is less than a target KL, the ECU 60 changes the VT towards VTmax. Thus, the direction in which the VT is changed is determined based on VTmax that is calculated irrespective of a change tendency (slope) of the characteristic line or the like at the current time.

Abstract: An object of the present invention is to calculate an estimated value of an amount of air blowing through an inside of a cylinder by scavenging that occurs in an engine equipped with a supercharger, that is, a scavenging amount. For this purpose, a control device of an engine equipped with a supercharger according to the present invention calculates an estimated value of an intake valve passing air amount from a measured value of an intake air amount, and calculates an estimated value of an in-cylinder air amount from a measured value or an estimated value of intake pipe pressure. From a difference between the estimated value of the intake valve passing air amount and the estimated value of the in-cylinder air amount, the estimated value of the scavenging amount is calculated.

Abstract: It is an object of the invention to enhance the possibility of realizing a required torque in a supercharging region where scavenging occurs in a control apparatus for a supercharged engine. In order to achieve this object, the control apparatus for the supercharged engine according to the invention determines an operation amount of an intake valve driving device from a target in-cylinder air amount that is calculated from a required torque, and determines an operation amount of a throttle from a target intake valve passing air amount that is obtained by adding an amount of air blowing through an interior of a cylinder to the target in-cylinder air amount.

Abstract: An object of the present invention is to improve controllability over a supercharging pressure in a transient state, in a control device of an internal combustion engine equipped with a turbo supercharger that determines a manipulated variable of an actuator which acts on a rotational speed of a turbine by feedback control based on a deviation between a target state quantity and an actual state quantity. To this end, a control device according to the present invention determines an opening degree of a throttle by feedforward control based on a target intake air amount, and determines a manipulated variable of the actuator by feedback control based on a deviation between a target intake pressure determined from the target intake air amount and an actual intake pressure.

Abstract: This invention has an object to enable update of learning values of a large number of grid points in one session of a learning operation and also to easily adjust learning speed and efficiency in a wide learning region. An engine 10 is provided with an ECU 60 for executing engine control by using various control parameters. The ECU 60 includes a learning map storing a learning value of the control parameter and executes weighting learning control of the learning value. In the weighting learning control, each time the control parameter is acquired, a weight wkij decreasing larger if a distance from a position of an acquired value zk of the control parameter to a grid point is larger is set to each of the grid points of the learning map. Then, on the basis of the acquired value zk of the control parameter and the weight wkij, the learning values Zij(k) at all the grid points are updated. As a result, all the learning values can be efficiently updated in one session of the learning operation.

Abstract: An object of this invention is to appropriately control the valve timing (VT) even in a case where a plurality of local maximum points or local minimum points exist on a characteristic line representing a relation between the VT and an air amount. An engine 10 includes VVTs 42 and 44 and the like. When a predetermined operation condition that a plurality of local maximum points exist on a load characteristic line representing a relation between the VT of an intake valve 32 and a load KL is established, an ECU 60 first calculates the VT corresponding to a maximum value KLmax of the load KL as a maximum air amount VT (VTmax). Subsequently, if the maximum value KLmax of the load is less than a target KL, the ECU 60 changes the VT towards VTmax. Thus, the direction in which the VT is changed is determined based on VTmax that is calculated irrespective of a change tendency (slope) of the characteristic line or the like at the current time.

Abstract: This internal combustion engine is provided with a variable compression ratio mechanism capable of changing a mechanical compression ratio by changing the volume of the combustion chamber at the top dead center. The pressure and temperature of remaining combusted gas within the combustion chamber at the time when the exhaust valve is closed in the intake stroke is measured or estimated, the pressure and temperature of intake air supplied into the combustion chamber after the exhaust valve is closed in the intake stroke is measured or estimated, and based on the assumption that the pressure and temperature of the remaining combusted gas which saturates the volume of the combustion chamber at the time when the exhaust valve is closed in the air intake stroke become, when the intake air is supplied to the combustion chamber, equal to the pressure and temperature of the intake air, the volume of the remaining combusted gas after the change is calculated.

Abstract: A control device for a multi-cylinder internal combustion engine that is equipped with a variable compression ratio mechanism includes an air-fuel ratio sensor, and a controller that determines whether or not actual mechanical compression ratios in cylinders of the internal combustion engine are uniform. The controller controls the variable compression ratio mechanism by decreasing a target mechanical compression ratio from a current first target mechanical compression ratio to a second target mechanical compression ratio without changing the amount of intake air and a fuel injection amount, and determines that the actual mechanical compression ratios in the cylinders are not uniform when the target mechanical compression ratio is set at the first target mechanical compression ratio if the differences in the output air-fuel ratios from the air-fuel ratio sensor for exhaust gases from the cylinders before and after the control of the variable compression ratio mechanism are not uniform.

Abstract: An internal combustion engine which is provided with a variable compression ratio mechanism which can change a mechanical compression ratio and a variable valve timing mechanism which can control a closing timing of an intake valve. A target operating point which can be reached after a fixed time without entering no-entry regions from the current operating point toward an operating point which satisfies the demanded intake air amount is calculated for an operating point which shows a combination of the mechanical compression ratio and the closing timing of the intake valve when the demanded intake air amount changes, and the mechanical compression ratio and the closing timing of the intake valve are made to change toward this target operating point.

Abstract: Disclosed is a control device, which controls an air-fuel ratio sensor that is mounted in an exhaust path of an internal-combustion engine. The air-fuel ratio sensor is capable of pumping oxygen in a gas. Normally (time t0-t1, time t3 or later), a positive voltage Vp1 is applied to a sensor element (FIG. 7A), and the air-fuel ratio is calculated (FIG. 7C) in accordance with a sensor current (FIG. 7B). A heater is driven after internal-combustion engine startup to heat the sensor element. In a process in which the sensor element temperature rises, a negative voltage Vm, which is oriented in a direction different from that of the positive voltage Vp1, is applied to the sensor element.

Abstract: A control device for an internal combustion engine. An object of the present invention is to provide a control device for an international combustion engine for highly accurate absolute pressure correction irrespective of the length of an adiabatic compression stroke period. When the number of cylinders in an engine is n (n is an integer of 2 or more), an adiabatic compression stroke period of one cylinder preceding another cylinder to be corrected into its absolute pressure by a 1/n cycle (ignition timing —IVC) is compared with a threshold CATH (step 100). In the step 100, the absolute pressure correction is carried out based on PV?=constant when the adiabatic compression stroke period is longer than the threshold CATH (step 110). On the other hand, the absolute pressure correction is carried out based on a value PIP detected by an intake pipe pressure sensor when the adiabatic compression stroke period is shorter than the threshold CATH.

Abstract: An internal combustion engine which is provided with a variable compression ratio mechanism which can change a mechanical compression ratio and a variable valve timing mechanism which can control a closing timing of an intake valve. No-entry regions (X1, X2) are set for a combination of the mechanical compression ratio, the closing timing of the intake valve, and the intake air amount. Furthermore, a no-entry layer is set so as to surround the no-entry region (X2). When the demanded intake air amount is made to decrease and the operating point moves toward the no-entry region (X2), the operating point is prohibited from entering the no-entry layer whereby the operating point is blocked from entering the no-entry region (X2).