A method of diagnosing deterioration of an exhaust emission control catalyst is provided. The catalyst includes an HC (hydrocarbon) adsorbing part and an oxidation catalyst part. The method includes estimating that an HC discharge amount discharged from the HC adsorbing part is larger than a first value, detecting a parameter relating to a reaction heat of the exhaust emission control catalyst, and diagnosing that the exhaust emission control catalyst is deteriorated when the detected parameter indicates a temperature value lower than a predetermined threshold. The deterioration diagnosis is performed under a first condition that the HC discharge amount is estimated to be larger than the first value.

Various methods and systems are provided for an exhaust gas recirculation (EGR) EGR cooler for an engine system. In one example, the EGR cooler includes a first section with a first group of tubes adapted to flow exhaust gases, and also includes a first group of passages formed by exterior surfaces of the first group of tubes and adapted to flow coolant from a coolant source. The EGR cooler also includes a second section including a second group of tubes adapted to flow coolant from the coolant source, and a second group of passages formed by exterior surfaces of the second group of tubes and adapted to flow the exhaust gas from the first group of tubes.

Various methods and systems are provided for an exhaust gas recirculation (EGR) EGR cooler for an engine system. In one example, the EGR cooler includes a first section with a first group of tubes adapted to flow exhaust gases, and also includes a first group of passages formed by exterior surfaces of the first group of tubes and adapted to flow coolant from a coolant source. The EGR cooler also includes a second section including a second group of tubes adapted to flow coolant from the coolant source, and a second group of passages formed by exterior surfaces of the second group of tubes and adapted to flow the exhaust gas from the first group of tubes.

Methods and systems are provided for adjusting fuel injections provided to a cylinder when a fuel rail pressure deviation from a threshold pressure is detected. In one example, a method may include reducing a total number of pilot and/or main fuel injections provided to a cylinder in a given cylinder cycle in response to a reduction of pressure in a fuel rail. In this way, the threshold rail pressure may be maintained, reducing the likelihood the engine will be derated.

Provided is a control device for an internal combustion engine that includes an EGR device equipped with an EGR cooler bypass passage and a flow-rate-ratio control valve equipped with a valve disc and capable of controlling a flow rate ratio. The control device is configured, when an opening degree control execution condition is met, to execute a vibration reduction control for controlling the flow-rate-ratio control valve such that the opening degree of the valve disc becomes greater than or equal to a vibration reduction opening degree that is greater than a minimum opening degree within an opening degree control range of the valve disc. The opening degree control execution condition includes a requirement that a parameter (pulsation level value) that becomes greater when exhaust pulsation acting on the valve disc is greater is equal to or greater than a first threshold value.

Provided is a control device for an internal combustion engine that includes an EGR device equipped with an EGR cooler bypass passage and a flow-rate-ratio control valve equipped with a valve disc and capable of controlling a flow rate ratio. The control device is configured, when an opening degree control execution condition is met, to execute a vibration reduction control for controlling the flow-rate-ratio control valve such that the opening degree of the valve disc becomes greater than or equal to a vibration reduction opening degree that is greater than a minimum opening degree within an opening degree control range of the valve disc. The opening degree control execution condition includes a requirement that a parameter (pulsation level value) that becomes greater when exhaust pulsation acting on the valve disc is greater is equal to or greater than a first threshold value.

A control device controls an internal combustion engine including: an EGR cooler bypass passage; and a flow-rate-ratio control valve capable of controlling, by adjustment of its opening degree, an EGR cooler ratio R. The control device is configured, during an EGR gas introduction operation, to execute an intake air temperature control for adjusting the opening degree such that an intake air temperature Tb approaches a target intake air temperature Tbt. In this intake air temperature control, the control device is configured, when a designated condition that, even if the adjustment of the opening degree is performed, there is a temperature difference obtained by subtracting the target intake air temperature Tbt from a value of the intake air temperature Tb to be achieved as a result of the adjustment of the opening degree is met, to execute an opening-degree update prohibition processing that prohibits an update of the opening degree.

A control device controls an internal combustion engine including: an EGR cooler bypass passage; and a flow-rate-ratio control valve capable of controlling, by adjustment of its opening degree, an EGR cooler ratio R. The control device is configured, during an EGR gas introduction operation, to execute an intake air temperature control for adjusting the opening degree such that an intake air temperature Tb approaches a target intake air temperature Tbt. In this intake air temperature control, the control device is configured, when a designated condition that, even if the adjustment of the opening degree is performed, there is a temperature difference obtained by subtracting the target intake air temperature Tbt from a value of the intake air temperature Tb to be achieved as a result of the adjustment of the opening degree is met, to execute an opening-degree update prohibition processing that prohibits an update of the opening degree.

An internal combustion engine includes a cam shifting system having a shifting unit rotatably fixed and axially moveable with respect to a camshaft. The shifting unit includes at least two cams configured to be selectively brought in contact with a cam follower and provided with a base circle and with at least one cam lobe. The shifting unit is provided with at least one groove having a shifting portion. A driving pin is operable to be selectively engaged with and disengaged from the shifting portion of the groove. Engagement between the driving pin and the shifting portion of the groove moves the shifting unit with respect to the camshaft. During the movement of the shifting unit the cam follower engages at least a portion of at least one cam lobe.

An internal combustion engine includes a cam shifting system having a shifting unit rotatably fixed and axially moveable with respect to a camshaft. The shifting unit includes at least two cams configured to be selectively brought in contact with a cam follower and provided with a base circle and with at least one cam lobe. The shifting unit is provided with at least one groove having a shifting portion. A driving pin is operable to be selectively engaged with and disengaged from the shifting portion of the groove. Engagement between the driving pin and the shifting portion of the groove moves the shifting unit with respect to the camshaft. During the movement of the shifting unit the cam follower engages at least a portion of at least one cam lobe.