There is a problem of a difficulty in estimating the temporal change of the MBT for each of cylinders with light calculation load and high accuracy. An object of the present invention is to provide a control device capable of detecting a temporal change in the fuel efficiency optimum ignition timing (MBT) for each of cylinders. Therefore, the control device for internal combustion engine includes a control unit (CPU) that estimates an optimum ignition timing of each of cylinders from the relationship between the phase angle (Tmax) at which the torque peaks and the phase angle (Pmax) at which the in-cylinder pressure peaks with respect to the ignition timing of the cylinder.

There is a problem of a difficulty in estimating the temporal change of the MBT for each of cylinders with light calculation load and high accuracy. An object of the present invention is to provide a control device capable of detecting a temporal change in the fuel efficiency optimum ignition timing (MBT) for each of cylinders. Therefore, the control device for internal combustion engine includes a control unit (CPU) that estimates an optimum ignition timing of each of cylinders from the relationship between the phase angle (Tmax) at which the torque peaks and the phase angle (Pmax) at which the in-cylinder pressure peaks with respect to the ignition timing of the cylinder.

A control system for a compression ignition engine is provided, which includes a combustion chamber, a throttle valve, an injector, an ignition, a swirl control valve, a sensor and a controller. The controller is configured to execute a first mode module, a second mode module, and a changing module to change an engine mode from a first mode to a second mode in response to a change demand. The changing module outputs signals to the throttle valve and the injector in response to the demand so that an air-fuel ratio of mixture gas becomes a stoichiometric air-fuel ratio, and outputs a signal to the swirl control valve so that an EGR gas amount decreases more than before the demand, and when the EGR gas amount is determined to be decreased to a given amount, the changing module causes the second mode module to start the second mode.

A control system for a compression ignition engine is provided, which includes a combustion chamber, a throttle valve, an injector, an ignition, a swirl control valve, a sensor and a controller. The controller is configured to execute a first mode module, a second mode module, and a changing module to change an engine mode from a first mode to a second mode in response to a change demand. The changing module outputs signals to the throttle valve and the injector in response to the demand so that an air-fuel ratio of mixture gas becomes a stoichiometric air-fuel ratio, and outputs a signal to the swirl control valve so that an EGR gas amount decreases more than before the demand, and when the EGR gas amount is determined to be decreased to a given amount, the changing module causes the second mode module to start the second mode.

An engine system control apparatus includes a parameter reception unit that receives parameters necessary for acquiring a pressure ratio of the low-pressure compressor and a pressure ratio of the high-pressure compressor, a pressure ratio acquisition unit that acquires the pressure ratio of the low-pressure compressor and the pressure ratio of the high-pressure compressor based on the parameters, an inter-compressor pressure ratio acquisition unit that acquires an inter-compressor pressure ratio obtainable by dividing the pressure ratio of the high-pressure compressor by the pressure ratio of the low-pressure compressor, and a control unit that controls the exhaust gas flowrate adjustment unit such that the inter-compressor pressure ratio becomes a predetermined pressure ratio for optimizing an operation efficiency of the engine system.

An engine system control apparatus includes a parameter reception unit that receives parameters necessary for acquiring a pressure ratio of the low-pressure compressor and a pressure ratio of the high-pressure compressor, a pressure ratio acquisition unit that acquires the pressure ratio of the low-pressure compressor and the pressure ratio of the high-pressure compressor based on the parameters, an inter-compressor pressure ratio acquisition unit that acquires an inter-compressor pressure ratio obtainable by dividing the pressure ratio of the high-pressure compressor by the pressure ratio of the low-pressure compressor, and a control unit that controls the exhaust gas flowrate adjustment unit such that the inter-compressor pressure ratio becomes a predetermined pressure ratio for optimizing an operation efficiency of the engine system.

Methods and systems are provided for conducting an ejector system diagnostic under conditions where an engine of a vehicle is not combusting air and fuel. In one example, a method comprises directing a positive pressure to the ejector system while the engine is off in order to communicate a negative pressure with respect to atmospheric pressure on a fuel system and an evaporative emissions system of the vehicle, and indicating that the ejector system is degraded responsive to the negative pressure not reaching a vacuum build threshold. In this way, the ejector system may be diagnosed under conditions where boosted engine operation is infrequent and/or of durations insufficient for conducting such an ejector system diagnostic.

Methods and systems are provided for conducting an ejector system diagnostic under conditions where an engine of a vehicle is not combusting air and fuel. In one example, a method comprises directing a positive pressure to the ejector system while the engine is off in order to communicate a negative pressure with respect to atmospheric pressure on a fuel system and an evaporative emissions system of the vehicle, and indicating that the ejector system is degraded responsive to the negative pressure not reaching a vacuum build threshold. In this way, the ejector system may be diagnosed under conditions where boosted engine operation is infrequent and/or of durations insufficient for conducting such an ejector system diagnostic.

An internal combustion engine includes an ignition plug and an electronic control unit. The electronic control unit is configured to: (i) execute a lean-burn operation in a first operation region, (ii) execute an operation in a second operation region at an air-fuel ratio lower than an air-fuel ratio during the lean-burn operation, and (iii) control a gas flow in a cylinder so that a ratio of a change in a gas flow speed around the ignition plug during ignition to a change in an engine rotation speed in a first engine rotation speed region within the first operation region is smaller than the ratio in a second engine rotation speed region within the second operation region.

An internal combustion engine includes an ignition plug and an electronic control unit. The electronic control unit is configured to: (i) execute a lean-burn operation in a first operation region, (ii) execute an operation in a second operation region at an air-fuel ratio lower than an air-fuel ratio during the lean-burn operation, and (iii) control a gas flow in a cylinder so that a ratio of a change in a gas flow speed around the ignition plug during ignition to a change in an engine rotation speed in a first engine rotation speed region within the first operation region is smaller than the ratio in a second engine rotation speed region within the second operation region.