Abstract: A control device includes an engine valve and a variable valve actuation mechanism that is able to change at least one of a valve operating angle and valve lift of the engine valve. When the at least one of the valve operating angle and the valve lift is larger than or equal to a prescribed upper limit, the control device increases an operating speed of the variable valve actuation mechanism as compared with when the at least one of the valve operating angle and the valve lift is smaller than the prescribed upper limit.

Abstract: A control device of an internal combustion engine according to the present invention executes air-fuel ratio control based on an output of an air-fuel ratio sensor provided at an upstream side of a catalyst, with correction based on an output of an oxygen sensor at a downstream side of the catalyst. When it is determined that a degree of an output tendency in a predetermined lean region is not less than a predetermined lean degree, and that a degree of an output tendency in a predetermined rich region is less than a predetermined rich degree based on lean tendency and rich tendency values representing output tendencies of the oxygen sensor, a limit is set to the correction in a direction to more suppress enriching of an air-fuel ratio as a degree is larger in which the output of the oxygen sensor is shifted to a lean side.

Abstract: An air-fuel ratio control apparatus for an internal combustion engine is provided. A controller is programmed to perform correction amount guard control allowing adjustment of a correction amount by setting a limit on the correction amount when an appearance frequency of a state where an output value from a downstream sensor is leaner than a predetermined value is equal to or higher than a predetermined value. When a state where the output value from the downstream sensor is leaner than the predetermined value lasts for a duration equal to or longer than a predetermined time, an incorporation speed at which, during learning control, the correction amount for sub feedback control is incorporated into a learning value is set to a larger value that when the duration is shorter than the predetermined time, and performance of the correction amount guard control is suppressed until the learning control is completed.

Abstract: An abnormality detecting device of an internal combustion engine according to the present invention includes a sensor nick abnormality detecting unit configured to detect a nick abnormality in a detecting element of a downstream side sensor which is provided in a downstream side of an exhaust gas purifying catalyst in an exhaust passage and generates an output corresponding to an oxygen concentration in exhaust gas, on the basis of a matter that a distribution of an output of the downstream side sensor is biased to an area in which the air-fuel ratio is leaner than a theoretical air-fuel ratio, and an inhibiting unit configured to inhibit detection of the nick abnormality of the detecting element by the sensor nick abnormality detecting unit in the case that an intake air amount exceeds a predetermined amount.

Abstract: An air-fuel ratio control apparatus for an internal combustion engine is provided. A controller is programmed to perform correction amount guard control allowing adjustment of a correction amount by setting a limit on the correction amount when an appearance frequency of a state where an output value from a downstream sensor is leaner than a predetermined value is equal to or higher than a predetermined value. When a state where the output value from the downstream sensor is leaner than the predetermined value lasts for a duration equal to or longer than a predetermined time, an incorporation speed at which, during learning control, the correction amount for sub feedback control is incorporated into a learning value is set to a larger value that when the duration is shorter than the predetermined time, and performance of the correction amount guard control is suppressed until the learning control is completed.

Abstract: A control device of an internal combustion engine according to the present invention executes air-fuel ratio control based on an output of an air-fuel ratio sensor provided at an upstream side of a catalyst, with correction based on an output of an oxygen sensor at a downstream side of the catalyst. When it is determined that a degree of an output tendency in a predetermined lean region is not less than a predetermined lean degree, and that a degree of an output tendency in a predetermined rich region is less than a predetermined rich degree based on lean tendency and rich tendency values representing output tendencies of the oxygen sensor, a limit is set to the correction in a direction to more suppress enriching of an air-fuel ratio as a degree is larger in which the output of the oxygen sensor is shifted to a lean side.

Abstract: A control device of an internal combustion engine according to the present invention has units configured to inject fuel at a first predetermined ratio from first and second fuel injection valves which are provided in each of cylinders to calculate a first value indicating a degree of variation in air-fuel ratios between the cylinders based on a output of the engine, and inject fuel at a second predetermined ratio therefrom to calculate a second value in the same manner. Furthermore, the control device has a unit configured to select one mode from modes relating to abnormality in the first fuel injection valve or the second fuel injection valve on the basis of the first and second values, and calculate a value indicating the degree of the variation in the air-fuel ratios between the cylinders, thereby calculating a fuel amount of the basis of them.

Abstract: A control device of an internal combustion engine according to the present invention has units configured to inject fuel at a first predetermined ratio from first and second fuel injection valves which are provided in each of cylinders to calculate a first value indicating a degree of variation in air-fuel ratios between the cylinders based on a output of the engine, and inject fuel at a second predetermined ratio therefrom to calculate a second value in the same manner. Furthermore, the control device has a unit configured to select one mode from modes relating to abnormality in the first fuel injection valve or the second fuel injection valve on the basis of the first and second values, and calculate a value indicating the degree of the variation in the air-fuel ratios between the cylinders, thereby calculating a fuel amount of the basis of them.

Abstract: An abnormality detecting device of an internal combustion engine according to the present invention includes a sensor nick abnormality detecting unit configured to detect a nick abnormality in a detecting element of a downstream side sensor which is provided in a downstream side of an exhaust gas purifying catalyst in an exhaust passage and generates an output corresponding to an oxygen concentration in exhaust gas, on the basis of a matter that a distribution of an output of the downstream side sensor is biased to an area in which the air-fuel ratio is leaner than a theoretical air-fuel ratio, and an inhibiting unit configured to inhibit detection of the nick abnormality of the detecting element by the sensor nick abnormality detecting unit in the case that an intake air amount exceeds a predetermined amount.

Abstract: A detecting apparatus that detects an abnormality of imbalance of air-fuel ratios among cylinders of a multi-cylinder internal combustion engine, which is equipped with a variable working angle mechanism of an intake valve, the detecting apparatus includes an abnormality detection portion that detects a parameter regarding rotational fluctuations of each of the cylinders and detects whether or not there is an abnormality of imbalance of air-fuel ratios among the cylinders. The abnormality detection portion refrains from determining that the air-fuel ratios are normal when the working angle at the time of detection of the parameter is within a predetermined large working angle range, and determines that the air-fuel ratios are normal when the working angle at the time of detection of the parameter is within a predetermined small working angle range that is on a small working angle side with respect to the large working angle range.

Abstract: A control apparatus of a variable valve system includes a variable valve timing mechanism that performs variable control of the valve timing of an intake valve of an internal combustion engine, a variable operation angle mechanism that performs variable control of the operation angle of the intake valve, and a control unit that performs drive control of the variable valve timing mechanism and the variable operation angle mechanism. The control unit sets an upper guard for the operation angle according to an actual value of the valve timing, and when a target value of the valve timing is a value on the retard side of a specified determining value, the control unit reinforces the upper guard compared with when the target value of the valve timing is not a value on the retard side of the specified determining value.

Abstract: A variable valve timing apparatus for an internal combustion engine, includes an actuator (15) that operates a first variable valve timing mechanism; a detecting portion (35) that detects a driving position of the actuator (15); and a control portion (21) that executes an initialization process only when a preset execution condition is satisfied. In the initialization process, the control portion drives the actuator (15) to one end of a driving range and sets the driving position detected in this state as an initial value, and then drives the actuator (15) to an opposite end of the driving range and reflects an offset amount of the driving position detected in that state with respect to an optimum value in the driving position to compensate for the offset amount. The execution condition includes a condition that an increase amount in acceleration required of the internal combustion engine (1) be equal to or greater than a preset first determining value.

Abstract: A detecting apparatus that detects an abnormality of imbalance of air-fuel ratios among cylinders of a multi-cylinder internal combustion engine, which is equipped with a variable working angle mechanism of an intake valve, the detecting apparatus includes an abnormality detection portion that detects a parameter regarding rotational fluctuations of each of the cylinders and detects whether or not there is an abnormality of imbalance of air-fuel ratios among the cylinders. The abnormality detection portion refrains from determining that the air-fuel ratios are normal when the working angle at the time of detection of the parameter is within a predetermined large working angle range, and determines that the air-fuel ratios are normal when the working angle at the time of detection of the parameter is within a predetermined small working angle range that is on a small working angle side with respect to the large working angle range.

Abstract: An internal combustion engine includes a valve timing change mechanism that changes the phase of an intake cam, and a lift amount change mechanism that changes lift amount by causing displacement of a control shaft. An electronic control unit performs a coordinated control in which the lift amount change mechanism is operated such that the position of the control shaft that is detected by a position detection sensor becomes the target position, and the valve timing change mechanism is operated according to a control state of the lift amount change mechanism. When a discrepancy between the actual position of the control shaft and the detected position thereof is estimated to be large, coordinated control is forbidden and the valve timing change mechanism is operated based on engine load.

Abstract: A control apparatus of a variable valve system includes a variable valve timing mechanism that performs variable control of the valve timing of an intake valve of an internal combustion engine, a variable operation angle mechanism that performs variable control of the operation angle of the intake valve, and a control unit that performs drive control of the variable valve timing mechanism and the variable operation angle mechanism. The control unit sets an upper guard for the operation angle according to an actual value of the valve timing, and when a target value of the valve timing is a value on the retard side of a specified determining value, the control unit reinforces the upper guard compared with when the target value of the valve timing is not a value on the retard side of the specified determining value.

Abstract: A control device includes an engine valve and a variable valve actuation mechanism that is able to change at least one of a valve operating angle and valve lift of the engine valve. When the at least one of the valve operating angle and the valve lift is larger than or equal to a prescribed upper limit, the control device increases an operating speed of the variable valve actuation mechanism as compared with when the at least one of the valve operating angle and the valve lift is smaller than the prescribed upper limit.

Abstract: A control device for a variable valve actuation system includes: an engine valve; a variable valve actuation mechanism that variably controls a valve timing of the engine valve and at least one of a valve operating angle and valve lift of the engine valve; a variable setting unit that variably sets a control range, in which at least one of the valve operating angle and the valve lift is controlled by the variable valve actuation mechanism, on the basis of the valve timing; a detecting unit that detects a plurality of valve timings of the engine valve in different modes in such a manner that the control range is changed; and a control range setting unit that variably sets the control range using one of the plurality of detected valve timings.

Abstract: An internal combustion engine includes a valve timing change mechanism that changes the phase of an intake cam, and a lift amount change mechanism that changes lift amount by causing displacement of a control shaft. An electronic control unit performs a coordinated control in which the lift amount change mechanism is operated such that the position of the control shaft that is detected by a position detection sensor becomes the target position, and the valve timing change mechanism is operated according to a control state of the lift amount change mechanism. When a discrepancy between the actual position of the control shaft and the detected position thereof is estimated to be large, coordinated control is forbidden and the valve timing change mechanism is operated based on engine load.

Abstract: An actuator control apparatus includes: an actuator that changes a state amount of an internal combustion engine; a sensor that detects an actual operation position of the actuator; a controller that controls the actuator to bring the actual operation position of the actuator to a target operation position set based on the operation state of the internal combustion engine; and a diagnosis portion that diagnoses the operation state of the actuator to be normal if the deviation between the target operation position and the actual operation position has been small for a predetermined time period and the amount by which the target operation position has changed in the predetermined time period is equal to or larger than a predetermined value. A method for controlling such an actuator control apparatus is also provided.

Abstract: An actuator control apparatus is provided which has: an actuator provided in an internal combustion engine at a position distant from combustion chambers to change an engine state amount; a sensor that detects the actual operation position of the actuator; a controller that controls the actuator to bring the actual operation position to a target operation position set based on the engine operation state; a diagnosis portion that diagnoses the actuator to be in an abnormal state when the deviation of the actual operation position from the target operation position has been larger than a reference amount for a reference time; and a setting portion that sets, upon the diagnosis by the diagnosis portion, the reference time such that the lower the engine coolant temperature, the longer the reference time, and the lower the ambient temperature, the longer the reference time corresponding to the engine coolant temperature.