Abstract: In an electronic throttle control system, a target intake pipe pressure as well as a presumed value for the intake pipe pressure is calculated, so that a deviation between the target value and the presumed value for the intake pipe pressure is calculated. The deviation is compensated in an advancing side by an amount corresponding to a delay of response in the throttle control system. An intake air amount passing through a throttle valve is calculated based on the above compensated deviation and a presumed intake air amount. A target opening degree of a throttle valve is finally calculated based on the above-calculated intake air amount passing through a throttle valve. Accordingly, a response and stability of the throttle control can be improved.

Abstract: A target throttle opening degree computing device of a control apparatus computes a target throttle opening degree of a throttle valve and includes a phase lead compensator. A filter filters the target throttle opening degree to provide an ultimate target throttle opening degree, which is used to drive a drive motor to adjust an opening degree of the throttle valve.

Abstract: When it is determined that an engine speed NE rapidly decreases (positive outcome at S210), a throttle increase amount TAu and a valve lift increase amount VLu are computed based on a decrease rate NEd of the engine speed NE (S220). Then, a target throttle opening degree TAt of a throttle valve and a target maximum valve lift VLt of an intake valve are increased by using the throttle increase amount TAu and the valve lift increase amount VLu (S230). As a result, a drop in the engine speed during idling is reliably suppressed.

Abstract: An apparatus for diagnosing deterioration of a NOx absorption-reduction catalyst provided at an exhaust path of an engine includes a sensor disposed upstream of the catalyst to sense a NOx concentration in emission gas, a calculating unit calculating a first ratio of emission of NOx to inflow of NOx or a second ratio of absorption of NOx to inflow of NOx, and a diagnosing unit which diagnoses deterioration of the catalyst using the first or second ratio as an indicator. The calculating unit calculates inflow of NOx based on an output of the sensor and either the flow volume of the emission gas or a correlation value of the flow volume of the emission gas, calculates the absorption of NOx based on the amount of rich components required for reducing the NOx, and calculates the emission of NOx based on the difference between the inflow and absorption of NOx.

Abstract: In an electronic throttle control system, a target intake pipe pressure as well as a presumed value for the intake pipe pressure is calculated, so that a deviation between the target value and the presumed value for the intake pipe pressure is calculated. The deviation is compensated in an advancing side by an amount corresponding to a delay of response in the throttle control system. An intake air amount passing through a throttle valve is calculated based on the above compensated deviation and a presumed intake air amount. A target opening degree of a throttle valve is finally calculated based on the above-calculated intake air amount passing through a throttle valve. Accordingly, a response and stability of the throttle control can be improved.

Abstract: A dead time in the case where an output of an air-fuel ratio sensor changes in a lean direction and a dead time in the case where the output changes in a rich direction are sensed respectively. The number of elements constituting data of past feedback correction amounts used for calculating a present feedback correction amount is changed in accordance with the larger one of the dead times. A lean direction response time and a rich direction response time are sensed respectively. A control gain is corrected in accordance with the lean direction response time when the output of the air-fuel ratio sensor changes in the lean direction. The control gain is corrected in accordance with the rich direction response time when the output changes in the rich direction.

Abstract: A target throttle opening degree computing device of a control apparatus computes a target throttle opening degree of a throttle valve and includes a phase lead compensator. A filter filters the target throttle opening degree to provide an ultimate target throttle opening degree, which is used to drive a drive motor to adjust an opening degree of the throttle valve.

Abstract: A dead time in the case where an output of an air-fuel ratio sensor changes in a lean direction and a dead time in the case where the output changes in a rich direction are sensed respectively. The number of elements constituting data of past feedback correction amounts used for calculating a present feedback correction amount is changed in accordance with the larger one of the dead times. A lean direction response time and a rich direction response time are sensed respectively. A control gain is corrected in accordance with the lean direction response time when the output of the air-fuel ratio sensor changes in the lean direction. The control gain is corrected in accordance with the rich direction response time when the output changes in the rich direction.

Abstract: When it is determined that an engine speed NE rapidly decreases (positive outcome at S210), a throttle increase amount TAu and a valve lift increase amount VLU are computed based on a decrease rate NEd of the engine speed NE (S220). Then, a target throttle opening degree TAt of a throttle valve and a target maximum valve lift VLt of an intake valve are increased by using the throttle increase amount TAu and the valve lift increase amount VLu (S230). As a result, a drop in the engine speed during idling is reliably suppressed.

Abstract: A lift time area is calculated based on an actual valve working angle of an intake valve and an engine rotational speed. Then, a control gain of a feedback control is set based on the lift time area.

Abstract: A lift time area is calculated based on an actual valve working angle of an intake valve and an engine rotational speed. Then, a control gain of a feedback control is set based on the lift time area.