Abstract: An internal combustion engine control device the present invention provides is a control device that can realize both of request torque and a request A/F for each of cylinder groups with high precision, even when the request A/F differs at each of the cylinder groups. The present control device sets a reference A/F within a range from the leanest A/F to the richest A/F out of the request A/Fs to the respective cylinder groups. The present control device calculates a target air quantity for realizing the request torque under the reference A/F, based on data that defines a relation between engine output torque and an air quantity in relation to an A/F. The present control device controls a throttle opening in accordance with the target air quantity, and controls fuel injection amounts of the respective cylinders in accordance with the request A/F s to the respective cylinder groups.

Abstract: An object of the present invention is to enable a requested efficiency by cylinder group that is requested from a viewpoint of exhaust gas performance to be realized precisely when an internal combustion engine having a single throttle shared by a plurality of cylinder groups, and having an exhaust gas purifying catalyst for each of the cylinder groups is operated at a different air-fuel ratio at each of the cylinder groups. To this end, a control device for the internal combustion engine provided by the present invention calculates an efficiency ratio of a representative efficiency determined based on the requested efficiency by cylinder group and a requested efficiency by cylinder group, and calculates a requested torque by cylinder group by dividing a requested torque by the efficiency ratio for each of the cylinder groups.

Abstract: A control device for an internal combustion engine provided by the present invention is a control device which can satisfy both a requirement relating to exhaust gas performance of the internal combustion engine and a requirement relating to operation performance by properly regulating a change speed of a required air-fuel ratio, in the internal combustion engine which uses torque and an air-fuel ratio as control variables. The control device receives the requirement relating to the exhaust gas performance of the internal combustion engine, and calculates an air-fuel ratio which satisfies the requirement as a required air-fuel ratio. When a predetermined reduction condition is not satisfied, an original required air-fuel ratio is directly determined as a final required air-fuel ratio.

Abstract: A control device for an internal combustion engine provided by the present invention is a control device which can satisfy a requirement concerning exhaust gas performance of the internal combustion engine, a requirement concerning fuel economy performance, and a requirement concerning operation performance with an excellent balance by properly regulating a change speed of a required air-fuel ratio and an ignition timing. The present control device keeps the ignition timing at an optimal ignition timing if a predetermined permission condition is not satisfied. However, when the permission condition is satisfied, the present control device controls the ignition timing so as to compensate for a difference which occurs between torque which is estimated from an operation of an actuator for air quantity control and required torque by the ignition timing.

Abstract: When a change amount of any one of a demanded torque, a demanded efficiency, and a demanded air-fuel ratio exceeds a predetermined threshold value, an internal combustion engine control apparatus provided by this invention makes a temporary adjustment to a value of any one of a demanded torque, a demanded efficiency and instructed efficiency, and a demanded air-fuel ratio in accordance with a type of demanded engine performance that is currently being given priority among various performances demanded of the internal combustion engine. In the present control apparatus, an actuator for air amount control is operated in accordance with a target air amount calculated based on a demanded torque and a demanded efficiency, an actuator for ignition timing control is operated in accordance with an instructed efficiency, and an actuator for fuel injection amount control is operated in accordance with a demanded air-fuel ratio.

Abstract: A control device is provided that generates a target air-fuel ratio by lessening a change speed of a required air-fuel ratio of an internal combustion engine. However, when a deterioration degree of a catalyst which is disposed in an exhaust passage of the internal combustion engine is a predetermined reference or more, lessening of the change speed of the required air-fuel ratio is stopped, or a lessening degree of the change speed of the required air-fuel ratio is decreased. The control device calculates a target air quantity for realizing the required torque under the target air-fuel ratio. For calculation of the target air quantity, data in which relationship of torque generated by the internal combustion engine and an air quantity taken into a cylinder is fixed by being related to an air-fuel ratio can be used.

Abstract: An embodiment (control apparatus) for an internal combustion engine according to the present invention determines, based on an output value of the downstream air-fuel ratio sensor disposed downstream of a three-way catalyst, determines which air-fuel ratio request, a rich request or a lean request, is occurring. The control apparatus sets a target upstream air-fuel ratio to a target rich air-fuel ratio when the rich request is occurring, and sets the target upstream air-fuel ratio to a target lean air-fuel ratio when the lean request is occurring. Each of the target rich air-fuel ratio and the target lean air-fuel ratio is varied depending on an intake air amount. Further, the control apparatus increases a purge amount of an evaporated fuel as a magnitude (air-fuel ratio change amount ?AF, |afLean?afRich|) of a difference between the target rich air-fuel ratio and the target lean air-fuel ratio becomes larger.

Abstract: A control apparatus for an internal combustion engine determines, based on an output value of the downstream air-fuel ratio sensor, an air-fuel ratio of a gas flowing into the catalyst that is set to either a “target rich ratio” or a “target lean ratio”, and determines a fuel injection amount. Disclosed is an evaporated fuel purge section for introducing an evaporated fuel generated in a fuel tank into an intake passage. The purge section starts the purge when the target air-fuel ratio is set to the target rich ratio at a purge execution condition satisfied time point at which a state has changed from a state in which the purge execution condition is unsatisfied to a state in which it is satisfied, and does not start the purge when the target air-fuel ratio is set to the target lean air-fuel ratio at the purge execution condition satisfied time point.

Abstract: A control device is provided that generates a target air-fuel ratio by lessening a change speed of a required air-fuel ratio of an internal combustion engine. However, when a deterioration degree of a catalyst which is disposed in an exhaust passage of the internal combustion engine is a predetermined reference or more, lessening of the change speed of the required air-fuel ratio is stopped, or a lessening degree of the change speed of the required air-fuel ratio is decreased. The control device calculates a target air quantity for realizing the required torque under the target air-fuel ratio. For calculation of the target air quantity, data in which relationship of torque generated by the internal combustion engine and an air quantity taken into a cylinder is fixed by being related to an air-fuel ratio can be used.

Abstract: An air-fuel ratio control apparatus of the present invention includes a determination section and a reverse direction correction introducing section. The determination section determines whether or not an output of the downstream air-fuel ratio sensor falls within a predetermined range whose center corresponds to a target value corresponding to the stoichiometric air-fuel ratio. When the output of the downstream air-fuel ratio sensor falls within the predetermined range, the reverse direction correction introducing section temporarily introduces, to an air-fuel ratio correction in a direction requested by the output, an air-fuel ratio correction in a direction opposite to the requested direction.

Abstract: A control device for an internal combustion engine provided by the present invention is a control device which can satisfy a requirement concerning exhaust gas performance of the internal combustion engine, a requirement concerning fuel economy performance, and a requirement concerning operation performance with an excellent balance by properly regulating a change speed of a required air-fuel ratio and an ignition timing. The present control device keeps the ignition timing at an optimal ignition timing if a predetermined permission condition is not satisfied. However, when the permission condition is satisfied, the present control device controls the ignition timing so as to compensate for a difference which occurs between torque which is estimated from an operation of an actuator for air quantity control and required torque by the ignition timing.

Abstract: Provided is an internal combustion engine system controller, including a sub-feedback learning section, a state determining section, and a learning update-speed setting section. The state determining section determines, to which of at least three states including: (a) a stable state in which a fluctuating state of a sub-feedback learning value is stable; (b) an unstable state in which the fluctuating state greatly fluctuates; and (c) an intermediate state between the stable state and the instable state (may be referred to as sub-stable state), the fluctuating state corresponds. The learning update-speed setting section sets an update speed of the sub-feedback learning value in accordance with the result of determination by the state determining section. Further, the learning update-speed setting section suppresses the occurrence of hunting of the sub-feedback learning value.

Abstract: A control apparatus of an internal combustion engine capable of appropriately reflecting various requests relating to the performance of the internal combustion engine. Specifically, the control device of the internal combustion engine acquires various requests relating to the performance of the internal combustion engine, and sets restricted ranges of the value of the control variable in accordance with the details of the requests. At this moment, the control device temporally changes the set restricted ranges for specific requests associated with the time integral value of the control variable rather than the instantaneous value of the control variable. Subsequently, the control device determines a final restricted range on the basis of the overlap between the restricted ranges set for each request, and determines the target value of the control variable in the final restricted range.

Abstract: A control device for an internal combustion engine provided by the present invention is a control device which can enhance precision of realization of required torque while enhancing emission performance by positively changing an air-fuel ratio. The present control device generates a target air-fuel ratio by lessening a change speed of a required air-fuel ratio of an internal combustion engine. However, in a situation in which the required air-fuel ratio is made rich with return from fuel cut, lessening of the change speed of the required air-fuel ratio is stopped, and the required air-fuel ratio is directly outputted as a target air-fuel ratio. The control device calculates a target air quantity for realizing the required torque under the target air-fuel ratio. For calculation of the target air quantity, data in which relationship of torque generated by the internal combustion engine and an air quantity taken into a cylinder is fixed by being related to an air-fuel ratio can be used.

Abstract: A monitoring apparatus including a catalytic converter, an upstream air-fuel ratio sensor, and a downstream air-fuel ratio sensor; calculates a sub feedback amount to have an air-fuel ratio represented based on an output value of the downstream air-fuel ratio sensor coincide with a stoichiometric air-fuel ratio; and controls an fuel injection amount based on an output value of the upstream air-fuel ratio sensor and the sub feedback amount, in such a manner that an air-fuel ratio of a mixture supplied to an engine coincides with the stoichiometric air-fuel ratio.

Abstract: An internal combustion engine control device the present invention provides is a control device that can realize both of request torque and a request A/F for each of cylinder groups with high precision, even when the request A/F differs at each of the cylinder groups. The present control device sets a reference A/F within a range from the leanest A/F to the richest A/F out of the request A/Fs to the respective cylinder groups. The present control device calculates a target air quantity for realizing the request torque under the reference A/F, based on data that defines a relation between engine output torque and an air quantity in relation to an A/F. The present control device controls a throttle opening in accordance with the target air quantity, and controls fuel injection amounts of the respective cylinders in accordance with the request A/F s to the respective cylinder groups.

Abstract: A control device for an internal combustion engine that enhances precision of realization of required torque while enhancing emission performance by positively changing an air-fuel ratio. The control device generates a target air-fuel ratio by lessening a change speed of a required air-fuel ratio of an internal combustion engine. However, when the required air-fuel ratio is made rich with return from fuel cut, lessening of the change speed of the required air-fuel ratio is stopped, and the required air-fuel ratio is directly outputted as a target air-fuel ratio. The control device calculates a target air quantity for realizing the required torque under the target air-fuel ratio. The control device manipulates an actuator for air quantity control in accordance with the target air quantity, and manipulates an actuator for fuel injection quantity control in accordance with the target air-fuel ratio.

Abstract: A fuel injection amount control apparatus disclosed in the present specification calculates a time integral value SDVoxslow by accumulating values each obtained by multiplying a deviation DVoxslow between an output value Voxs of a downstream air-fuel ratio sensor disposed downstream of a catalyst and a predetermined downstream target value Voxsref by a predetermined adjusting gain K (step 1140), and stores it as a sub FB learning value KSFBg (step 1165). The apparatus sets different values from each other in the adjusting gain K when the sub FB learning value is increasing and in the adjusting gain K when the sub FB learning value is decreasing, in such a manner that an absolute value of a difference between a magnitude of an increasing speed of the sub FB learning value and a magnitude of a decreasing speed of the FB learning value becomes smaller (step 1125 through step 1135).

Abstract: An air-fuel ratio control device includes an air-fuel ratio sensor provided upstream from a three-way catalyst, and an oxygen sensor provided downstream from the three-way catalyst. The air-fuel ratio control device controls the fuel supply amount based on the output from the air-fuel ratio sensor, and compensates for errors in the air-fuel ratio sensor by correcting the fuel supply amount based on the output from the oxygen sensor. The fuel supply correction amount is calculated based on an integral term that integrates the deviation between the output from the downstream air-fuel ratio sensor and the target air-fuel ratio. When a fuel supply adjustment control is executed, the value of the integral term in the sub-feedback control is not updated for a predetermined period after the fuel supply adjustment control ends. The actual air-fuel ratio is thus brought to the target air-fuel ratio in an appropriate manner.

Abstract: An inter-cylinder air-fuel ratio imbalance determining apparatus for an internal combustion engine includes an air-fuel ratio sensor; fuel injection valves; an instructed fuel injection amount control unit; and an imbalance determination unit configured: to acquire a time-differential-value corresponding value that is an amount of change per predetermined time in an output value of the sensor or a detected air-fuel ratio represented by the output value; to acquire a positive gradient corresponding value based on a positive value of the time-differential-value corresponding value; to acquire a negative gradient corresponding value based on a negative value of the time-differential-value corresponding value; to determine an imbalance determination threshold based on a magnitude of a ratio of the negative gradient corresponding value to the positive gradient corresponding value; and to determine whether inter-cylinder air-fuel ratio imbalance has occurred by comparing a magnitude of the negative gradient corresp