Abstract: A control device for an internal combustion engine, said control device implementing a lean control, whereby the air-fuel ratio of the exhaust gas flowing into an exhaust purification catalyst is set to a lean air-fuel ratio setting, and a rich control, whereby the air-fuel ratio of the exhaust gas flowing into the exhaust purification catalyst is set to a rich air-fuel ratio setting. When the amount of oxygen absorbed by the exhaust purification catalyst during lean control reaches or exceeds a criterion storage amount, a control is executed to switch to rich control. In addition, a control is executed to set the lean air-fuel ratio setting for a first intake air amount so as to be richer than the lean air-fuel ratio setting for a second intake air amount that is less than the first intake air amount.

Abstract: This control device for an internal combustion engine equipped with an exhaust purification catalyst, which is disposed in an exhaust passage of the internal combustion engine and capable of storing oxygen, includes: a downstream air-fuel ratio detection means that is disposed downstream of the exhaust purification catalyst in the exhaust flow direction; and an inflow air-fuel ratio control means that controls the air-fuel ratio of exhaust gas flowing into the exhaust purification catalyst. If the outflow air-fuel ratio detected by the downstream air-fuel ratio detection means is equal to or less than a rich-determination air-fuel ratio, which is richer than the stoichiometric air-fuel ratio, the inflow air-fuel ratio control means sets the target air-fuel ratio of exhaust gas flowing into the exhaust purification catalyst continuously or intermittently leaner than the stoichiometric air-fuel ratio until the oxygen storage amount of the exhaust purification catalyst reaches a prescribed storage amount.

Abstract: A control device for an internal combustion engine, equipped with: an exhaust purification catalyst capable of storing oxygen; a downstream-side air-fuel ratio sensor arranged downstream in the direction of flow of exhaust from the exhaust purification catalyst; and an air-fuel ratio control device that controls the air-fuel ratio such that air-fuel ratio of the exhaust flowing into the exhaust purification catalyst reaches a target air-fuel ratio.

Abstract: A control apparatus which is capable of determining an abnormality of a stopping operation of an exhaust valve without using a dedicated sensor for detecting the abnormality in an internal combustion engine including a valve stop mechanism capable of maintaining the exhaust valve and an intake valve in a valve closed state is provided. It is discriminated whether or not there is a change to a rich side of a air fuel ratio of gas detected by a main A/F sensor at the time of a fuel cut for all the cylinders associated with a valve stop request for the exhaust valves and intake valves of all the cylinders. Then, when it is discriminated that there is the change to the rich side of the air fuel ratio of the gas, it is determined that the stopping operation of the exhaust valve is not performed in a normal manner in at least one cylinder.

Abstract: This control device for an internal combustion engine includes: an upstream catalyst; a downstream catalyst that is provided further downstream than the upstream catalyst in the exhaust flow direction; a downstream air-fuel ratio detection means that is provided between these catalysts; a storage amount estimation means that estimates the oxygen storage amount of the downstream catalyst; and an inflow air-fuel ratio control device that controls the air-fuel ratio of the exhaust gas flowing into the upstream catalyst such that the air-fuel ratio of the exhaust gas reaches a target air-fuel ratio. In a rich control during normal operation, the target air-fuel ratio is set lean if the air-fuel ratio detected by the downstream air-fuel ratio detection means is rich, and the target air-fuel ratio is set rich if the upstream catalyst oxygen storage amount is equal to or greater than the upstream reference storage amount.

Abstract: A control apparatus for an internal combustion engine configured to control the internal combustion engine is provided with: a first F/B controlling device configured to perform first F/B control in which an air-fuel ratio of a gas flowing into a three way catalyst converges to a target air-fuel ratio, on the basis of an output value of an air-fuel ratio sensor; a second F/B controlling device configured to perform second F/B control in which the target air-fuel ratio or the output value of the air-fuel ratio sensor is corrected such that an output voltage value of an oxygen concentration sensor matches a target output value; a learning device configured to learn an output characteristic of the oxygen concentration sensor; and a target value setting device configured to set the target output value according to a learning value of the output characteristic.

Abstract: Provided is a control apparatus for an internal combustion engine, which can determine whether or not there is a failure concerning a switching of an operational state of an intake valve, in the internal combustion engine that includes a valve stop mechanism that is capable of switching the operational state of the intake valve between a valve operating state and a valve closed/stopped state, without the need of adding a new sensor for the failure determination. An intake variable valve operating apparatus (66) is provided that includes a valve stop mechanism capable of switching the operational state of the intake valve (62) between the valve operating state and the valve closed/stopped state. A crank angle sensor (72) is provided for detecting the crank angle of the internal combustion engine (12). An intake pressure sensor (56) is provided for detecting the actual intake pressure pim.

Abstract: An exhaust gas control apparatus for an internal combustion engine, controls an exhaust operation of the internal combustion engine (200) provided with an exhaust gas purification catalyst (216) in an exhaust passage (215). The exhaust gas control apparatus for the internal combustion engine is provided with a warming-up device configured to warm up the exhaust gas purification catalyst; and an oxygen supplying device (220, 221) configured to supply oxygen to the exhaust gas purification catalyst after the end of the warm-up. This makes it possible to preferably desorb sulfur adsorbed to the exhaust gas purification catalyst during warm-up. It is therefore possible to suppress a reduction in purification ability of the exhaust gas purification catalyst due to sulfur coating.

Abstract: Invention suppresses deterioration of emission if there is air-fuel ratio imbalance among cylinders.

Abstract: Valve stopping control is performed that changes an operating state of an intake valve and an exhaust valve to a closed-valve stopped state when executing a fuel-cut operation. A device is provided that sets an in-cylinder return-time target air-fuel ratio for an initial two return cycles when returning from a fuel-cut operation. The return-time target air-fuel ratio is set so that respective air-fuel ratios of air-fuel mixtures of fuel and air injected into the same cylinder for respective cycles during the initial return cycles each become values that fall within a combustible range, and so that even if a total amount of fuel injected into the same cylinder for the initial return cycles is supplied into the cylinder during an arbitrary single cycle, the air-fuel ratio of the air-fuel mixture of the total amount of fuel and air becomes a value that falls within the combustible range.

Abstract: An engine includes an intake variable valve mechanism and an exhaust variable valve mechanism. An ECU causes all intake valves in all cylinders to stop in a closed state by means of intake variable valve mechanism when performing a fuel-cut operation, including when the engine is stopped. The ECU causes at least one exhaust valve in all cylinders to stop in an open state by means of exhaust variable valve mechanism. When executing a fuel-cut operation, needless compression can be avoided by stopping the exhaust valves in an open state, while protecting a catalyst from deterioration caused by contact with intake air by stopping the intake valves in a closed state. The amount of oil consumption of the engine, and electric power consumption, vibrations and a tendency for spontaneous ignition to occur at cranking time can be improved.

Abstract: A control apparatus for an internal combustion engine is provided, the control apparatus being capable of effectively suppressing the inflow of fresh air into a catalyst due to an operational delay of the valve stop mechanism when an execution request for fuel cut is issued. There is provided a valve stop mechanism capable of changing the operational states of intake valves and exhaust valves between a valve operating state and a valve closed/stopped state. The operational states of the intake and exhaust valves are changed into the valve closed/stopped state, if the engine rotational speed decreases to or below a predetermined rotational speed when the engine rotational speed is higher than the predetermined rotational speed in a case where an execution request for fuel cut is detected and the temperature of the catalyst is not lower than a predetermined temperature during operation of an internal combustion engine.

Abstract: A control apparatus for an internal combustion engine configured to control the internal combustion engine is provided with: a first F/B controlling device configured to perform first F/B control in which an air-fuel ratio of a gas flowing into a three way catalyst converges to a target air-fuel ratio, on the basis of an output value of an air-fuel ratio sensor; a second F/B controlling device configured to perform second F/B control in which the target air-fuel ratio or the output value of the air-fuel ratio sensor is corrected such that an output voltage value of an oxygen concentration sensor matches a target output value; a learning device configured to learn an output characteristic of the oxygen concentration sensor; and a target value setting device configured to set the target output value according to a learning value of the output characteristic.

Abstract: An engine includes variable valve mechanisms capable of causing an intake valve and an exhaust valve to stop. An ECU estimates poisoning states of catalysts, and executes and prohibits stopping of the valves based on the poisoning states. When stopping of the valves is prohibited during a fuel-cut operation, the ECU drives a crankshaft of the engine by means of a motor to idle the engine. Thus, even in a hybrid vehicle in which the engine is stopped during a fuel-cut operation, a sufficient amount of oxygen can be rapidly supplied to the catalysts by utilizing a pumping action of pistons, and the catalysts can be caused to recover from rich poisoning efficiently.

Abstract: Provided is a control apparatus for an internal combustion engine which can successfully determine whether or not a failure concerning a stopping operation of an exhaust valve has occurred, without the need of providing a dedicated sensor for the failure determination. An intake variable valve operating apparatus (62) and an exhaust variable valve operating apparatus (64) are included that have valve stop mechanisms capable of switching each operational state of an intake valve (58) and an exhaust valve (60) between a valve operating state and a valve closed/stopped state.

Abstract: Provided is a control apparatus for an internal combustion engine that can favorably achieve compatibility between suppressing deterioration of a catalyst and suppressing progression of rich poisoning thereof when the internal combustion engine has a configuration that performs valve stopping control during a fuel-cut operation. Variable valve operating apparatuses are provided having valve stop mechanisms that can respectively change an operating state of an intake valve and an exhaust valve between a valve operating state and a closed-valve stopped state. When an integrated fuel injection amount is equal to or greater than a predetermined value ? when executing a fuel-cut operation, it is determined that rich poisoning of an upstream catalyst is in a progressed state. In that case, valve stopping control of the intake and exhaust valves is prohibited to thereby supply oxygen to the upstream catalyst.

Abstract: A control apparatus for an internal combustion engine is provided, which is capable of suppressing deterioration of exhaust emission due to an unburned fuel contained in oil which enters a combustion chamber during valve stop control while preventing inflow of fresh air to a catalyst, at a time of valve return following return from fuel cut. Variable valve operating apparatuses having valve stop mechanisms capable of changing operation states of an intake valve and an exhaust valve between valve operation states and valve closed and stopped states are included. Valve stop control that changes the operation states of the intake valve and the exhaust valve to the valve closed and stopped states is performed, at a time of execution of the fuel cut. When a return request from the fuel cut with the valve stop control is detected, a fuel is supplied to a combustion chamber before the operation state of the exhaust valve is returned to the valve operation state.

Abstract: An engine includes an intake variable valve mechanism and an exhaust variable valve mechanism. An ECU causes all intake valves in all cylinders to stop in a closed state by means of intake variable valve mechanism when performing a fuel-cut operation, including when the engine is stopped. The ECU causes at least one exhaust valve in all cylinders to stop in an open state by means of exhaust variable valve mechanism. When executing a fuel-cut operation, needless compression can be avoided by stopping the exhaust valves in an open state, while protecting a catalyst from deterioration caused by contact with intake air by stopping the intake valves in a closed state. The amount of oil consumption of the engine, and electric power consumption, vibrations and a tendency for spontaneous ignition to occur at cranking time can be improved.

Abstract: Provided is a control apparatus for an internal combustion engine which can successfully determine whether or not a failure concerning a stopping operation of an exhaust valve has occurred, without the need of providing a dedicated sensor for the failure determination. An intake variable valve operating apparatus (62) and an exhaust variable valve operating apparatus (64) are included that have valve stop mechanisms capable of switching each operational state of an intake valve (58) and an exhaust valve (60) between a valve operating state and a valve closed/stopped state.

Abstract: Provided is a control apparatus for an internal combustion engine, which can determine whether or not there is a failure concerning a switching of an operational state of an intake valve, in the internal combustion engine that includes a valve stop mechanism that is capable of switching the operational state of the intake valve between a valve operating state and a valve closed/stopped state, without the need of adding a new sensor for the failure determination. An intake variable valve operating apparatus (66) is provided that includes a valve stop mechanism capable of switching the operational state of the intake valve (62) between the valve operating state and the valve closed/stopped state. A crank angle sensor (72) is provided for detecting the crank angle of the internal combustion engine (12). An intake pressure sensor (56) is provided for detecting the actual intake pressure pim.