An exhaust passage 53 includes: a first passage (high-speed passages 24b, 25b, and 26b); and a second passage (low-speed passages 24c, 25c, and 26c). A turbine housing 560 is connected to the exhaust passage 53 downstream from the collector 54. An exhaust device 100 of an engine 1 includes a valve (an exhaust variable valve 3) to open and close the first passage. A controller (an engine controller 7) closes the valve if an engine speed of the engine 1 is lower than a predetermined engine speed and opens the valve if the engine speed of the engine 1 is higher than or equal to the predetermined engine speed. The controller opens the valve even though the engine speed of the engine 1 is lower than the predetermined engine speed if performing the fuel cut control.

An exhaust passage 53 includes: a first passage (high-speed passages 24b, 25b, and 26b); and a second passage (low-speed passages 24c, 25c, and 26c). A turbine housing 560 is connected to the exhaust passage 53 downstream from the collector 54. An exhaust device 100 of an engine 1 includes a valve (an exhaust variable valve 3) to open and close the first passage. A controller (an engine controller 7) closes the valve if an engine speed of the engine 1 is lower than a predetermined engine speed and opens the valve if the engine speed of the engine 1 is higher than or equal to the predetermined engine speed. The controller opens the valve even though the engine speed of the engine 1 is lower than the predetermined engine speed if performing the fuel cut control.

Methods and systems are provided for an engine system configured with a wide range active compressor and high pressure EGR. In one example, a compressor may include an active casing treatment with a slideable sleeve may be adjusted to direct air flow through either a choke slot and surge slot to control compressor efficiency, thereby maintaining EGR flow. In another example, the compressor may comprise a variable inlet device to regulate air flow through the compressor, thereby adjusting compressor efficiency and also maintaining EGR flow.

Methods and systems are provided for an engine system configured with a wide range active compressor and high pressure EGR. In one example, a compressor may include an active casing treatment with a slideable sleeve may be adjusted to direct air flow through either a choke slot and surge slot to control compressor efficiency, thereby maintaining EGR flow. In another example, the compressor may comprise a variable inlet device to regulate air flow through the compressor, thereby adjusting compressor efficiency and also maintaining EGR flow.

A hybrid-electric propulsion system includes a turbomachine, a propulsor coupled to the turbomachine, and an electrical system, the electrical system including an electric machine coupled to the turbomachine. A method for operating a hybrid-electric propulsion system includes operating, by one or more computing devices, the turbomachine in an idle operating condition; receiving, by the one or more computing devices, a command to accelerate the turbomachine while operating the turbomachine in the idle operating condition; and providing, by the one or more computing devices, electrical power to the electric machine to add power to the turbomachine and increase an acceleration of the turbomachine in response to the received command to accelerate the turbomachine.

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 method and a control device are provided for an internal combustion engine structured to vary a mechanical compression ratio by varying a range of slide of a piston with respect to a cylinder bore. A control process includes: acquiring a temperature correlating with a cylinder bore wall temperature; fixing the mechanical compression ratio to a preset compression ratio point, in response to a condition that the acquired temperature is lower than a preset temperature point; and setting the preset temperature point higher than a point corresponding to a point of the cylinder bore wall temperature at which condensed water occurs in the cylinder bore.

A controller for an internal combustion engine is configured to execute a dither control process, a purge control process, and a limiting process. The dither control process operates the fuel injection valves such that at least one of the cylinders is a lean combustion cylinder, in which the air-fuel ratio is leaner than the stoichiometric air-fuel ratio, and at least another one of the cylinders is a rich combustion cylinder, in which the air-fuel ratio is richer than the stoichiometric air-fuel ratio. The purge control process controls the purge flow rate by operating the adjustment device. The limiting process limits the purge control process such that, when the dither control process is being executed, the purge flow rate is reduced as compared to a case in which the dither control process is not being executed.

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.