Abstract: An abnormality determination apparatus for an intake amount control mechanism according to the invention includes a control portion which sets an allowable range of an opening amount of a throttle valve which provided in an intake passageway of an internal combustion engine based at least on an index value of an engine operation state, including an operation amount of accelerator, and on a lift working angle of an intake valve, and which determines that an abnormality is present in a state of driving of the throttle valve if an actual opening amount of the throttle valve is outside the allowable range set.

Abstract: When it is determined that an engine speed NE rapidly decreases (positive outcome at S210), a throttle increase amount TAu and a valve lift increase amount VLU are computed based on a decrease rate NEd of the engine speed NE (S220). Then, a target throttle opening degree TAt of a throttle valve and a target maximum valve lift VLt of an intake valve are increased by using the throttle increase amount TAu and the valve lift increase amount VLu (S230). As a result, a drop in the engine speed during idling is reliably suppressed.

Abstract: A control apparatus for an internal combustion engine provided with a fuel supply mechanism capable of adjusting a fuel supply amount includes a flow rate sensor that detects an intake air flow rate that represents a flow rate of air admitted into a combustion chamber of the internal combustion engine, a pressure sensor that detects a pressure of the air admitted into the combustion chamber of the internal combustion engine, a characteristic change estimation unit that estimates a characteristic change of the internal combustion engine in accordance with the intake air flow rate detected by the flow rate sensor and the intake air pressure detected by the pressure sensor, and a fuel supply mechanism control unit that controls the fuel supply mechanism. The fuel supply mechanism control unit controls the fuel supply mechanism such that the characteristic change in the internal combustion engine is compensated in accordance with an estimation performed by the characteristic change estimation unit.

Abstract: To provide a control apparatus of an engine that improves vehicle drivability by controlling a variable valve mechanism. The control apparatus of an engine prohibits the changing of the valve duration of an intake valve during a stop of an engine.

Abstract: A valve characteristic changing mechanism is supplied with oil discharged from an electric oil pump in addition to oil discharged from a mechanical oil pump that is driven by an operation of an internal combustion engine. Driving of the electric oil pump is controlled such that a work rate of the electric oil pump increases as a temperature of the oil supplied to the valve characteristic changing mechanism increases, or as a viscosity of the oil is reduced.

Abstract: A control apparatus for an internal combustion engine provided with a fuel supply mechanism capable of adjusting a fuel supply amount includes a flow rate sensor that detects an intake air flow rate that represents a flow rate of air admitted into a combustion chamber of the internal combustion engine, a pressure sensor that detects a pressure of the air admitted into the combustion chamber of the internal combustion engine, a characteristic change estimation unit that estimates a characteristic change of the internal combustion engine in accordance with the intake air flow rate detected by the flow rate sensor and the intake air pressure detected by the pressure sensor, and a fuel supply mechanism control unit that controls the fuel supply mechanism. The fuel supply mechanism control unit controls the fuel supply mechanism such that the characteristic change in the internal combustion engine is compensated in accordance with an estimation performed by the characteristic change estimation unit.

Abstract: A lift time area is calculated based on an actual valve working angle of an intake valve and an engine rotational speed. Then, a control gain of a feedback control is set based on the lift time area.

Abstract: A failure diagnosis for a slide sensor of a variable valve mechanism is performed when a valve working angle is at a value in the initial state. The initial state is set to a valve characteristic state where the valve working angle is at the maximum value. The maximum valve working angle corresponds to the refuge running performable region in which an engine can be started and refuge running can be performed. Therefore, even when it is difficult to adjust the valve working angle using rotation of a spiral cam due to a failure in the slide sensor, the refuge running can be performed only by maintaining the initial state by maintaining control. It is thus possible to increase reliability of the refuge running in the case where a failure has occurred in the variable valve mechanism.

Abstract: A control apparatus calculates a exhaust gas air-fuel ratio of a plurality of cylinders, in which the operation angle of an intake valve is set to a predetermined operation angle, e.g., a maximum operation angle, based on a value output from an air-fuel ratio sensor so as to minimize a variation in an fuel injection quantity between the plurality of cylinders by that exhaust gas air-fuel ratio. That is, the exhaust gas air-fuel ratio of the plurality of cylinders, in which the valve opening characteristics of the intake valve and an exhaust valve are set such that the intake air amount to be introduced into the plurality of cylinders is limited by the opening amount of a throttle valve, for example, and not limited by the valve opening characteristics of the intake valve or the exhaust valve is calculated, and the variation in the fuel injection quantity among the plurality of cylinders is then reduced by that exhaust gas air-fuel ratio.

Abstract: A control device of a multicylinder internal combustion engine provided with a valve operating characteristic control means for controlling a valve operating characteristic of at least one of an intake valve and exhaust valve, which estimates an intake difference of cylinders and limits a control range of said valve operating characteristic in accordance with said estimated intake difference.

Abstract: After a delay control for extending a period from when an engine stop request is made to when the engine actually stops is started, the electronic control unit changes the valve timing and the valve duration of an intake valve to valve timing and valve duration suitable for starting the engine. When changing the valve timing and the valve duration after the start of the delay control, the electronic control unit changes one of the valve timing and the valve duration of the intake valve based on the other such a valve overlap becomes less than or equal to a predetermined value.

Abstract: An electronic control unit sets a target valve actuation parameter in accordance with an operating state of an internal combustion engine, and controls a variable valve actuation mechanism such that an actual valve actuation parameter of an intake valve becomes equal to the target valve actuation parameter. The variable valve actuation mechanism changes a valve actuation parameter of the intake valve. From before an initial fuel injection is performed to when a starting process of the engine is completed, the electronic control unit sets the target valve actuation parameter to an engine starting valve actuation parameter at which the valve closing timing of the intake valve coincides with or is close to a bottom dead center of the intake valve.

Abstract: A variable valve timing and lift mechanism includes an actuator that adjusts the period in which an intake valve is held open by moving a drive element. When a control unit switches the duration, the control unit controls the actuator so that the duration is changed at a first speed when the duration is equal to a first value, and at a second speed when the duration is equal to a second value that is smaller than the first value. The absolute value of the second speed is smaller than the absolute value of the first speed. In effect, the actuator is controlled so that when the duration is in a short-duration range, the duration changes more slowly than when the duration is in a long-duration range.

Abstract: A control device for a variable valve mechanism that avoids the overheating an actuator while reducing adverse effects on the driveability of a vehicle. The actuator adjusts the lift of an intake valve by moving a drive element, and a sensor is used to determine whether the actuator will overheat. A control unit stops the drive element if the lift adjusted by the actuator is equal to or larger than a first predetermined value, when the control unit determines that the actuator will overheat. The actuator may be an electric actuator. In this case, the actuator maintains the drive element in a fixed position when supply of electric power to the actuator is interrupted. The control unit stops the drive element, and interrupts the supply of electric power to the actuator.

Abstract: An engine includes two or more banks, VVTL mechanisms provided for the respective banks for changing the operating characteristics of intake valves, and a control device that controls the VVTL mechanisms. The control device controls the VVTL mechanisms by integrating a plurality of pieces of control information corresponding to the respective VVTL mechanisms. When one of the pieces of control information becomes unknown, the control device performs a process of learning the control information with respect to the VVTL mechanism for the bank involving the unknown control information, and continues to control the VVTL mechanism for the other bank or banks, using the corresponding control information.

Abstract: A valve characteristic estimation device applied to an internal combustion engine provided with a valve characteristic adjustment mechanism for varying a valve characteristic including at least one of a valve open period and a lift amount of an intake valve. The estimation device detects intake air amount and intake air pressure of the engine, and calculates an estimated value for the valve characteristic based on the detected values of the intake air amount and the intake air pressure. Accordingly, the valve characteristic of the intake valve is accurately estimated.

Abstract: A device for controlling an internal combustion engine, comprising a variable valve mechanism for varying opening areas (valve lift) or the working angles (valve-opening periods) of at least either the intake valves or the exhaust valves, wherein a pressure in the cylinder is calculated based on the opening area or the working angle of at least either the intake valve or the exhaust valve varied by the variable valve mechanism, and the internal combustion engine is controlled based on the pressure in the cylinder. Upon calculating the pressure in the cylinder based on the opening areas or the working angles of the intake and exhaust valves, it is possible to more suitably control the internal combustion engine based not only upon the peak combustion pressure in the cylinder like when a combustion pressure sensor is used but also upon a pressure in the cylinder at a moment other than the peak combustion pressure.

Abstract: A control apparatus calculates a exhaust gas air-fuel ratio of a plurality of cylinders, in which the operation angle of an intake valve is set to a predetermined operation angle, e.g., a maximum operation angle, based on a value output from an air-fuel ratio sensor so as to minimize a variation in an fuel injection quantity between the plurality of cylinders by that exhaust gas air-fuel ratio. That is, the exhaust gas air-fuel ratio of the plurality of cylinders, in which the valve opening characteristics of the intake valve and an exhaust valve are set such that the intake air amount to be introduced into the plurality of cylinders is limited by the opening amount of a throttle valve, for example, and not limited by the valve opening characteristics of the intake valve or the exhaust valve is calculated, and the variation in the fuel injection quantity among the plurality of cylinders is then reduced by that exhaust gas air-fuel ratio.

Abstract: In an control apparatus and a control method for an internal combustion engine with a variable valve-characteristic mechanism that changes a valve characteristic that includes at least one of the duration and the maximum lift of an intake valve, the operating position of the mechanism is detected, and the mechanism is controlled so that a value of the valve characteristic corresponding to the operating position is equal to a target value corresponding to an engine operating state. After the target value is changed so that the intake valve opens/closes in accordance with a specific value of the valve characteristic, the operating position of the mechanism is learned as a reference position for the control of the valve characteristic. An intake-air-amount adjustment device upstream of the intake valve is controlled to offset the change in the amount of intake air caused by changing the target value when the reference position is learned.

Abstract: A control apparatus for an internal combustion engine includes a controller. The controller determines whether a misfire occurs in any of the plurality of cylinders. If it is determined that a misfire occurs, the controller determines whether an intake valve is unable to open due to the malfunction of a valve lift mechanism. If it is determined that the intake valve is unable to open, the controller stops operation of the fuel injection valve corresponding to a cylinder of the plurality of cylinders, in which the misfire occurs, to stop a fuel supply to the cylinder from a next intake stroke until the malfunction of the valve lift mechanism is corrected, regardless of whether the internal combustion engine stops.