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: 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 air-fuel ratio imbalance determining apparatus that is configured to sequentially stop a fuel injection for each of cylinders in accordance with a firing (ignition) order by changing the intake valves and exhaust valves of the cylinder whose fuel injection is stopped from a valve operating state to a valve resting state. After a predetermined time elapses (time-point tp), an upstream-side air-fuel ratio value obtained based on an output value of an upstream air-fuel ratio sensor disposed in the exhaust passage which becomes a value corresponding to an air-fuel ratio of the final gas. The determining apparatus obtains that value as data relating to an air-fuel ratio of the cylinder which discharged the final gas, and determines whether or not an air-fuel ratio imbalance is occurring based on the data relating to the air-fuel ratio of each of the cylinders.

Abstract: The present invention has its object to provide a control apparatus for an internal combustion engine including a variable valve operating mechanism which is capable of accurately and effectively identifying an abnormality-occurring cylinder during operation while preventing the deterioration of a catalyst. A fuel injection valve which is capable of injecting fuel for each cylinder is provided. Variable valve operating mechanisms which are capable of halting the operation of the intake and exhaust valves in the closed state for each cylinder are provided. An abnormality evaluation index value is acquired during the operation of the internal combustion engine and, based on the abnormality evaluation index value, an abnormality which has occurred in at least one cylinder in the internal combustion engine is detected.

Abstract: The present invention makes it possible to favorably change valve-opening characteristics of a valve using a simplified configuration without leading to an increase in the number of components and also without causing an increase of friction due to sliding, in a valve operating apparatus for an internal combustion engine in which the valve-opening characteristics of the valve are variable. A changeover mechanism for switching the connection/disconnection of rocker arms disposed between cams and a valve is provided. When a slide pin reaches a displacement end in the retreating direction of changeover pin, the biasing force of a return spring acting on changeover pins is received by an engaging part between a notch part provided in the slide pin and a lock pin in a state separated from a camshaft.

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: An object of the present invention is to provide an abnormality detection device that is used with an internal combustion engine having a valve drive mechanism capable of halting the drive of at least one of an intake valve and an exhaust valve, and able to detect the abnormalities of a valve drive halt function. The internal combustion engine includes a knock sensor capable of sensing the seating sound of the intake valve and/or the exhaust valve. An ECU detects whether a control signal given to the valve drive mechanism is a valve drive signal or a valve halt signal. In accordance with the result of detection by the ECU and the presence of the seating sound in an output of the knock sensor, the abnormality detection device judges whether or not the valve drive mechanism is abnormal.

Abstract: When, for example, a predetermined operating condition such as a fuel cut operating condition is satisfied (time-point tfc), an air-fuel ratio imbalance among cylinder determining apparatus sequentially stops a fuel injection for each of cylinders in accordance with a firing (ignition) order, and changes intake valves and exhaust valves of the cylinder whose fuel injection is stopped from a valve operating state to a valve resting state. Consequently, after a time-point at which an exhaust gas (final gas) is discharged from a cylinder into an exhaust passage (the exhaust gas being generated from a fuel injected lastly for that cylinder), no new gas is discharged from that cylinder. Accordingly, when a predetermined time elapses (time-point tp), an upstream-side air-fuel ratio abyfs obtained based on an output value of an upstream air-fuel ratio sensor disposed in the exhaust passage becomes a value corresponding to an air-fuel ratio of the final gas.

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.

Abstract: When the operating characteristics of an intake valve are changed by an intake valve stop mechanism, an ECU outputs a command signal (control on) to a solenoid. At this time, a timing, at which the command signal is output to the solenoid, is determined on the basis of a rotational position of a crankshaft, calculated from a signal of a crank position sensor. However, the output timing is corrected on the basis of a rotational phase difference of a camshaft with respect to the crankshaft.

Abstract: There is provided a control apparatus for an internal combustion engine, which can favorably reduce a load necessary for cranking at the time of the next start, while preventing the fresh air inflow to a catalyst at the time of the stop of the internal combustion engine. A valve stop command is issued to an electrically-driven actuator so that the operational states of intake and exhaust valves becomes a valve closed/stopped state when fuel supply is stopped in response to an establishment of a predetermined stop condition of the internal combustion engine. Then, to return the operational states of the intake and exhaust valves to a valve operating state after the completion of the stopping operation of the internal combustion engine, a valve return command is issued to the actuator, and a crankshaft is rotationally driven by a predetermined angle required to return the operational states of the intake and exhaust valves to the valve operating state.

Abstract: Provided is a control apparatus, which can successfully suppress that deterioration of combustion is caused in response to inflow of a large amount of blow-by gas to cylinders at the time of a valve return from a valve stop state in an internal combustion engine including a positive crankcase ventilation system and a variable valve operating mechanism that is capable of stopping at least one valve of an intake valve and exhaust valve in a closed state. A valve stop control is performed which stops the intake valve and exhaust valve in a closed state when a fuel cut of the internal combustion engine is executed. A deviation amount ?A/F between a predetermined target air fuel ratio and an actual air fuel ratio detected by an A/F sensor at the time of a valve return is obtained. A correction is performed to decrease a fuel injection amount by a fuel amount equivalent to the deviation amount ?A/F at the time of the subsequent valve returns.

Abstract: The present invention makes it possible to favorably change valve-opening characteristics of a valve using a simplified configuration without leading to an increase in the number of components and also without causing an increase of friction due to sliding, in a valve operating apparatus for an internal combustion engine in which the valve-opening characteristics of the valve are variable. A changeover mechanism for switching the connection/disconnection of rocker arms disposed between cams and a valve is provided. When a slide pin reaches a displacement end in the retreating direction of changeover pin, the biasing force of a return spring acting on changeover pins is received by an engaging part between a notch part provided in the slide pin and a lock pin in a state separated from a camshaft.

Abstract: Provided is a variable valve operating apparatus for an internal combustion engine, which can favorably reduce electric power consumption in a vehicle system that may stop the internal combustion engine during power-up of the vehicle system. A changeover mechanism 90 is provided which is capable of switching between a connection state in which a first rocker arm 96 and a second rocker arm 98 are in connection with each other via a changeover pin 112, 118 and a disconnection state in which the connection is released. The changeover mechanism 90 performs energization of actuators 130 for each cylinder in a case in which fuel supply to the internal combustion engine 12 is stopped in response to an establishment of a predetermined stop condition.

Abstract: The present invention has its object to provide a control apparatus for an internal combustion engine including a variable valve operating mechanism which is capable of accurately and effectively identifying an abnormality-occurring cylinder during operation while preventing the deterioration of a catalyst. A fuel injection valve which is capable of injecting fuel for each cylinder is provided. Variable valve operating mechanisms which are capable of halting the operation of the intake and exhaust valves in the closed state for each cylinder are provided. An abnormality evaluation index value is acquired during the operation of the internal combustion engine and, based on the abnormality evaluation index value, an abnormality which has occurred in at least one cylinder in the internal combustion engine is detected.

Abstract: An object of the present invention is to provide an abnormality detection device that is used with an internal combustion engine having a valve drive mechanism capable of halting the drive of at least one of an intake valve and an exhaust valve, and able to detect the abnormalities of a valve drive halt function. The internal combustion engine includes a knock sensor capable of sensing the seating sound of the intake valve and/or the exhaust valve. An ECU detects whether a control signal given to the valve drive mechanism is a valve drive signal or a valve halt signal. In accordance with the result of detection by the ECU and the presence of the seating sound in an output of the knock sensor, the abnormality detection device judges whether or not the valve drive mechanism is abnormal.

Abstract: During a fuel cut, a recommended reactivated cylinder and a reactivatable cylinder are determined based on the stopped positions of an intake valve and an exhaust valve (step 104). A fastest reactivatable cylinder is then determined based on the crank angle, from among the recommended reactivated cylinder and the reactivatable cylinder (step 108). Also, the rotating direction of a motor when a variable valve drive apparatus starts to be driven again when the fastest reactivatable cylinder is made the reactivated cylinder is also determined. When a reactivation command is output, operation resumes from the fastest reactivatable cylinder when the situation calls for rapid reactivation (step 124). When the situation does not call for rapid reactivation, operation resumes from the recommended reactivated cylinder (step 118).

Abstract: A stopping position control apparatus and method for an internal combustion engine, over which an automatic stop/restart control is executed, is suggested. With the stopping position control apparatus and method, the crankshaft stopping position control is executed accurately by minimizing the influence of the loads placed on the internal combustion engine by auxiliary devices. The position at which the crankshaft stops when the internal combustion engine is automatically stopped is controlled by controlling the engine speed at which ignition is stopped. When issuance of a command to automatically stop the internal combustion engine is predicted, the auxiliary devices of the internal combustion engine are stopped before the internal combustion engine is automatically stopped.

Abstract: A stopping position control apparatus and method for an internal combustion engine, over which an automatic stop/restart control is executed, is suggested. With the stopping position control apparatus and method, the crankshaft stopping position control is executed accurately by minimizing the influence of the loads placed on the internal combustion engine by auxiliary devices. The position at which the crankshaft stops when the internal combustion engine is automatically stopped is controlled by controlling the engine speed at which ignition is stopped. When issuance of a command to automatically stop the internal combustion engine is predicted, the auxiliary devices of the internal combustion engine are stopped before the internal combustion engine is automatically stopped.