Abstract: In a variable valve unit provided with a variable valve mechanism that varies opening characteristics of an engine valve by rotary motion of a control shaft, an actuator that generates a rotary motion of the control shaft, a stopper restricting the rotary motion of the control shaft, and an angle sensor capable of outputting signals corresponding to angle positions of the control shaft, when the signal of the angle sensor at an angle position where the rotation of the control shaft is restricted by the stopper are learned, the actuator is controlled such that the control shaft is pressed against the stopper, after which drive torque of the actuator is reduced and with the drive torque reduced, signals of the then-angle sensor are stored.

Abstract: At the time of obtaining a difference in intake air amount between right and left banks in a V-type engine, a target value of a lift-amount/operation-angle-varying mechanism provided for each of the banks is set to a target value at which flow velocity of intake air passing through an intake valve becomes almost sound velocity. In a state in which the flow velocity of intake air passing through the intake valve becomes almost sound velocity, a difference in the intake air amount in the right and left banks is detected and, to reduce the difference, a correction value for a target value of a valve lift is set for each of the banks.

Abstract: A determination is made as to whether or not knocking is actually occurring inside a combustion chamber (5), and on the basis of the knocking detection result, a knocking-correlated parameter (octane number, alcohol concentration, compression ratio of the engine), which is a parameter having a correlation with knocking, is estimated. A knocking occurrence timing in the combustion chamber (5) is then predicted on the basis of the estimated knocking-correlated parameter. A knocking limit ignition timing, which is the ignition timing furthest toward the advanced side at which knocking does not occur, is calculated on the basis of the predicted knocking occurrence timing, and an ignition device (11) is controlled to perform spark ignition at the knocking limit ignition timing.

Abstract: In an engine provided with a valve lift amount variable mechanism and a center phase variable mechanism for an intake valve, a region between a region where a flow rate of an intake air passing through the intake valve reaches a sonic speed and a region where an intake air amount does not substantially change relative to a change in an opening area of the intake valve is made to be a learning region. Then, in order to resolve an error in intake air amount in the learning region, a correction value for correcting control process of the valve lift amount variable mechanism is learned. When the learning of the correction value is converged, the learning correction value is corrected with an occupied rate of the valve lift amount variable mechanism in the influence ratio between influences on the two mechanisms in relation to the error.

Abstract: In a variable valve unit provided with a variable valve mechanism that varies opening characteristics of an engine valve by rotary motion of a control shaft, an actuator that generates a rotary motion of the control shaft, a stopper restricting the rotary motion of the control shaft, and an angle sensor capable of outputting signals corresponding to angle positions of the control shaft, when the signal of the angle sensor at an angle position where the rotation of the control shaft is restricted by the stopper are learned, the actuator is controlled such that the control shaft is pressed against the stopper, after which drive torque of the actuator is reduced and with the drive torque reduced, signals of the then-angle sensor are stored.

Abstract: In an engine provided with a valve lift amount variable mechanism and a center phase variable mechanism for an intake valve, a region between a region where a flow rate of an intake air passing through the intake valve reaches a sonic speed and a region where an intake air amount does not substantially change relative to a change in an opening area of the intake valve is made to be a learning region. Then, in order to resolve an error in intake air amount in the learning region, a correction value for correcting control process of the valve lift amount variable mechanism is learned. When the learning of the correction value is converged, the learning correction value is corrected with an occupied rate of the valve lift amount variable mechanism in the influence ratio between influences on the two mechanisms in relation to the error.

Abstract: A determination is made as to whether or not knocking is actually occurring inside a combustion chamber (5), and on the basis of the knocking detection result, a knocking-correlated parameter (octane number, alcohol concentration, compression ratio of the engine), which is a parameter having a correlation with knocking, is estimated. A knocking occurrence timing in the combustion chamber (5) is then predicted on the basis of the estimated knocking-correlated parameter. A knocking limit ignition timing, which is the ignition timing furthest toward the advanced side at which knocking does not occur, is calculated on the basis of the predicted knocking occurrence timing, and an ignition device (11) is controlled to perform spark ignition at the knocking limit ignition timing.

Abstract: At the time of obtaining a difference in intake air amount between right and left banks in a V-type engine, a target value of a lift-amount/operation-angle-varying mechanism provided for each of the banks is set to a target value at which flow velocity of intake air passing through an intake valve becomes almost sound velocity. In a state in which the flow velocity of intake air passing through the intake valve becomes almost sound velocity, a difference in the intake air amount in the right and left banks is detected and, to reduce the difference, a correction value for a target value of a valve lift is set for each of the banks.

Abstract: A determination is made as to whether or not knocking is actually occurring inside a combustion chamber (5), and on the basis of the knocking detection result, a knocking-correlated parameter (octane number, alcohol concentration, compression ratio of the engine), which is a parameter having a correlation with knocking, is estimated. A knocking occurrence timing in the combustion chamber (5) is then predicted on the basis of the estimated knocking-correlated parameter. A knocking limit ignition timing, which is the ignition timing furthest toward the advanced side at which knocking does not occur, is calculated on the basis of the predicted knocking occurrence timing, and an ignition device (11) is controlled to perform spark ignition at the knocking limit ignition timing.

Abstract: An internal combustion engine (1) causes an air/fuel mixture in a cylinder to combust due to ignition by a spark plug (14). The engine controller (50) calculates a crank angle at knock on the basis of an operating state of the engine (1) (53–54), calculates a knock intensity on the basis of this crank angle at knock (54), calculates a limit ignition timing at which knock is not generated, on the basis of the knock intensity (54), and controls the ignition timing of the spark plug (14) to the limit ignition timing at which knock is not generated (55). Therefore, suitable control of the ignition timing is achieved, by means of a small number of adaptation steps.

Abstract: An internal combustion engine (1) causes an air/fuel mixture in a cylinder to combust due to ignition by a spark plug (14). The engine controller (50) calculates a temperature and pressure in the cylinder on the basis of the operating state of the engine (1) (531), calculates a limit ignition timing at which knock is not generated, on the basis of the temperature and pressure in the cylinder (54), and controls an ignition timing of the spark plug (14) to the limit ignition timing at which knock is not generated (55). Therefore, suitable control of the ignition timing is achieved, by means of a small number of adaptation steps.

Abstract: Fuel properties estimating apparatus for an internal combustion engine includes a controller to determine an estimated component concentration of a component in a fuel. The controller calculates an air-fuel correction quantity in accordance with an actual air fuel ratio of the engine; and calculates an air-fuel ratio sensitivity correction quantity from the air-fuel ratio correction quantity and a fuel properties correction quantity calculated from a most recent value of the component concentration. The controller then determines a new value of the estimated component concentration in accordance with the air-fuel ratio sensitivity correction quantity.

Abstract: An internal combustion engine control apparatus basically comprises a reference intake air quantity calculating section, a maximum intake air quantity calculating section and an engine control section. The reference intake air quantity calculating section is configured to calculate a reference intake air quantity corresponding to when an intake air is taken in as a sonic flow. The maximum intake air quantity calculating section is configured to calculate a theoretical maximum intake air quantity. The engine control section is configured to control the engine by using an intake air quantity function between a first value obtained by dividing the reference intake air quantity by the maximum intake air quantity and a second value obtained by dividing an actual intake air quantity corresponding to the valve characteristics of the intake valve by the maximum intake air quantity.

Abstract: In an internal combustion engine (1), air is taken into a cylinder (5) from an intake passage (30) through an intake valve (15). The amount of air taken into the cylinder (5) is controlled to a target intake air amount by having an engine controller (31) operate an intake throttle (23) in accordance with an accelerator opening (APO), taking into account a predetermined response delay (T2). The engine controller (31) calculates a predicted value (Qc1) of the intake air amount on the basis of the accelerator opening (APO), and controls a fuel injector (21) to inject fuel in a target fuel injection amount (Ti) which corresponds to this predicted value (Qc1) at a predetermined timing. In so doing, an improvement is achieved in the degree of precision with which air-fuel ratio control is performed when the internal combustion engine (1) accelerates or decelerates.

Abstract: An internal combustion engine control apparatus basically comprises a reference intake air quantity calculating section, a maximum intake air quantity calculating section and an engine control section. The reference intake air quantity calculating section is configured to calculate a reference intake air quantity corresponding to when an intake air is taken in as a sonic flow. The maximum intake air quantity calculating section is configured to calculate a theoretical maximum intake air quantity. The engine control section is configured to control the engine by using an intake air quantity function between a first value obtained by dividing the reference intake air quantity by the maximum intake air quantity and a second value obtained by dividing an actual intake air quantity corresponding to the valve characteristics of the intake valve by the maximum intake air quantity.

Abstract: In an internal combustion engine (1), air is taken into a cylinder (5) from an intake passage (30) through an intake valve (15). The amount of air taken into the cylinder (5) is controlled to a target intake air amount by having an engine controller (31) operate an intake throttle (23) in accordance with an accelerator opening (APO), taking into account a predetermined response delay (T2). The engine controller (31) calculates a predicted value (Qc1) of the intake air amount on the basis of the accelerator opening (APO), and controls a fuel injector (21) to inject fuel in a target fuel injection amount (Ti) which corresponds to this predicted value (Qc1) at a predetermined timing. In so doing, an improvement is achieved in the degree of precision with which air-fuel ratio control is performed when the internal combustion engine (1) accelerates or decelerates.

Abstract: A cylinder intake air quantity determination device is configured to calculate a manifold internal air quantity based on an inflow air quantity and an outflow air quantity of an intake manifold. Then, a manifold internal pressure is calculated based on the manifold internal air quantity and an intake air temperature, and a cylinder internal pressure corresponding to a crank angle is calculated based on the previous cylinder intake air quantity. The cylinder intake air quantity is then calculated based on the manifold internal pressure, the cylinder internal pressure, and the intake air temperature. Thus, the cylinder intake air quantity determination device is configured to calculate the cylinder intake air quantity with a good precision.

Abstract: An internal combustion engine (1) causes an air/fuel mixture in a cylinder to combust due to ignition by a spark plug (14). An engine controller (50) calculates an ignition delay of the gas in the cylinder on the basis of an operational state of the engine (1)(53), and it calculates a knock generation index which is an indicator of the occurrence of knock on the basis of the ignition delay (53). The controller (50) calculates a limit ignition timing at which knock is not generated, on the basis of the knock generation index (54), and by controlling the ignition timing of the spark plug (14) to the limit ignition timing (55), appropriate control of the ignition timing is achieved by means of a small number of adaptation steps.

Abstract: An internal EGR parameter estimating device is configured to estimate the internal EGR quantity based on the quantity of blow-by gas that blows by during an overlap period when both the intake valve(s) and the exhaust valve(s) are open. The blow-by gas quantity is calculated based on the intake air pressure and the exhaust gas pressure during the overlap period and the effective cross sectional area opening formed by the intake and exhaust valves. The overlap period is divided into intervals of a prescribed period and the interval cross sectional area opening during each interval is calculated.

Abstract: A system and method control intake air of an internal combustion engine. The engine has at least one combustion chamber provided with intake valves together with an intake manifold provided with a throttle valve. The opening and closure timings of the intake valves are adjustable entirely independently by electromagnetic drivers from the crankshaft position to control the amount of intake air supplied to the combustion chamber. The system and method provide a response adjustment to variable valve timing control of the intake valves for unthrottled intake air control.