Abstract: A vehicle includes an engine, a fueling system, an exhaust assembly, and a controller. The fueling system controls fuel to the engine. The exhaust assembly releases combustion gas from the engine and includes at least one sensor and a catalytic converter. The controller is configured to control the engine, the fueling system and the exhaust assembly. The controller evaluates engine state and an output from the at least one sensor and commands a fueling strategy to control an oxygen storage capacity of the catalytic converter based on the engine state and output from the at least one sensor.

Abstract: A vehicle includes an engine, a fueling system, an exhaust assembly, and a controller. The fueling system controls fuel to the engine. The exhaust assembly releases combustion gas from the engine and includes at least one sensor and a catalytic converter. The controller is configured to control the engine, the fueling system and the exhaust assembly. The controller evaluates engine state and an output from the at least one sensor and commands a fueling strategy to control an oxygen storage capacity of the catalytic converter based on the engine state and output from the at least one sensor.

Abstract: EGR gas quantity information, which indicates a quantity of the EGR gas flowing into a cylinder of an internal combustion engine, is obtained by an ECU. A combustion stop delay control operation, which delays execution of a combustion stop control operation, is executed by the ECU when the quantity of the EGR gas flowing into the cylinder is larger than a normal combustion determination threshold value. When the quantity of the EGR gas flowing into the cylinder becomes equal to or smaller than the normal combustion determination threshold value, the combustion stop control operation is enabled by the ECU.

Abstract: While an engine is an idling state and an EGR opening degree is increased stepwise from a specified opening degree, a variation in engine speed (a standard deviation in engine speed) is repeatedly computed. After that, a specified step amount is successively reduced from the EGR opening degree and the variation in engine speed is successively computed until the EGR opening degree becomes less than or equal to a specified value. Then, a maximum value of the EGR opening degrees where the variation in engine speed becomes minimum is learned as the full-close position.

Abstract: When a constant driving voltage is applied to a motor driving an EGR valve so that the EGR opening degree is varied, an angular speed of the EGR valve becomes minimal at a position where the driving torque of the EGR valve becomes maximal. In view of this, while an opening degree of the EGR valve is varied with a constant driving voltage applied to the motor, the EGR opening degree where the angular speed becomes minimal is learned as a full-close position.

Abstract: An emission control system for an engine includes an upstream sensor provided upstream of a catalyst in a flow direction of exhaust gas, a downstream sensor provided downstream of the catalyst to detect an air-fuel ratio so that the air-fuel ratio approaches a target air-fuel ratio in a sub feedback control, a constant current supply portion which changes an output characteristic of the downstream sensor by applying a constant current on a pair of electrodes thereof. A characteristic control portion controls the constant current supply portion in the sub feedback control to advance a timing of lean detection of the downstream sensor when the air-fuel ratio is richer than the target air-fuel ratio, and to advance a timing of rich detection of the downstream sensor when the air-fuel ratio is leaner than the target air-fuel ratio.

Abstract: When a constant driving voltage is applied to a motor driving an EGR valve so that the EGR opening degree is varied, an angular speed of the EGR valve becomes minimal at a position where the driving torque of the EGR valve becomes maximal. In view of this, while an opening degree of the EGR valve is varied with a constant driving voltage applied to the motor, the EGR opening degree where the angular speed becomes minimal is learned as a full-close position.

Abstract: While an engine is an idling state and an EGR opening degree is increased stepwise from a specified opening degree, a variation in engine speed (a standard deviation in engine speed) is repeatedly computed. After that, a specified step amount is successively reduced from the EGR opening degree and the variation in engine speed is successively computed until the EGR opening degree becomes less than or equal to a specified value. Then, a maximum value of the EGR opening degrees where the variation in engine speed becomes minimum is learned as the full-close position.

Abstract: A gas temperature sensor is provided in an EGR passage. When a specified learning executing condition is established, the EGR valve is compulsorily rotated from a reference position in a valve-close direction and then rotated in a valve-open direction over the reference position. While the EGR valve is rotated in such a manner as to pass a full-close position, an opening degree of the EGR valve at which the variation in gas temperature becomes minimum is learned as the full-close position of the EGR valve.

Abstract: EGR gas quantity information, which indicates a quantity of the EGR gas flowing into a cylinder of an internal combustion engine, is obtained by an ECU. A combustion stop delay control operation, which delays execution of a combustion stop control operation, is executed by the ECU when the quantity of the EGR gas flowing into the cylinder is larger than a normal combustion determination threshold value. When the quantity of the EGR gas flowing into the cylinder becomes equal to or smaller than the normal combustion determination threshold value, the combustion stop control operation is enabled by the ECU.