Provided are a valve stop mechanism capable of switching intake valves and exhaust valves of deactivated cylinders between an openable/closable state and a closed state, and an engine speed control unit which controls the engine speed. The engine speed control unit controls the engine speed in such a manner that the amount of change in the engine speed with respect to time is reduced, as compared with a case in which a specific condition is not satisfied, when the specific condition that switching by the valve stop mechanism is not completed, and that connection between an engine and a power transmission unit is released is satisfied after issuance of a switching request from one of a reduced-cylinder operation and an all-cylinder operation to the other thereof.

A fuel pump system of a hybrid vehicle is provided. The fuel pump system prevents a fuel pump from continuing to operate when fuel is exhausted, whereby the fuel pump may be damaged. The pressure of fuel is measured in response to exhaustion of fuel, and when the pressure of fuel is low, fuel is circulated within the fuel pump instead of being supplied to the engine side, thereby preventing the fuel pump from being stuck due to frictional heat.

A device for measuring temperature of a turbine wheel in a turbocharger includes: a guide that passes infrared ray generated from the turbine wheel and includes a coolant path; a protection unit that protects an optical head which senses the infrared ray; and a signal processing unit that measures a temperature of the turbine wheel by processing a signal corresponding to the sensed infrared ray.

Methods and systems are provided for estimating exhaust pressure based on an exhaust air/fuel ratio sensor. In one example, a method may comprise estimating an exhaust pressure based on periodic waveform outputs of an exhaust air/fuel ratio (AFR) sensor, and adjusting at least one engine operating parameter based on the estimated exhaust pressure. The exhaust pressure may be estimated based on one or more of the standard deviation and frequency of the periodic waveform outputs.

A ducted combustion system includes a combustion chamber and a fuel injector in fluid connection with the combustion chamber, which includes an orifice opening from an injector tip of the fuel injector, the orifice injecting fuel into the combustion chamber as a fuel jet, the fuel jet flowing, within the combustion chamber, in a fuel flow direction. The system includes at least one duct disposed within the combustion chamber, the at least one duct being disposed such that the fuel jet, at least partially, enters one of the at least one ducts upon being injected into the combustion chamber. The at least one duct may be configured for having a flow field air stream within the duct, prior to entrance of the fuel jet, the flow field air stream having a flow direction that is substantially similar to the fuel flow direction.

A method for controlling engine revolution per minute (RPM) includes: a frequency deriving process for deriving a frequency from change in engine RPM detected by a detector by a controller during driving of the engine; a frequency conversion process for converting a derivation frequency derived in the frequency deriving process into a conversion frequency via a predetermined conversion process by the controller; a frequency comparison process for comparing an amplitude of the conversion frequency at which engine RPM is to be changed among conversion frequencies converted in the frequency conversion process with an amplitude of a reference frequency pre-inputted to the controller; and a fuel injection amount adjusting process for deriving a correction value based on a result derived in the frequency comparison process, for applying the derived correction value, and for controlling an injector by the controller to adjust a fuel injection amount.

In an electronic control unit, a basic injection quantity calculation part calculates a basic injection quantity value as a target of fuel value, which an injector injects, by using an actual accelerator operation angle value, an actual engine rotation speed value and at least one of an actual vehicle speed value and an actual acceleration value. When the actual vehicle speed value or the acceleration value deviates largely from the estimated value, a correction value calculation part calculates an injection quantity correction value for the basic injection quantity value and a final injection quantity calculation part calculates a final injection quantity value by correcting the basic injection quantity value with the correction value. A driving control part controls driving of the injector so that the injector injects fuel of the final injection quantity value determined by correcting the basic injection quantity value with the correction value.

A control apparatus of an engine including intake and exhaust valves and a variable valve timing mechanism for varying open and close timings is provided. The apparatus includes a processor configured to execute an increasing amount controlling module for performing a fuel amount increase control in which a fuel injection amount is increased to decrease an exhaust gas temperature, and a valve controlling module for controlling, via the variable valve timing mechanism, an overlapping period in which the intake and exhaust valves are both opened on intake stroke. When the increasing amount controlling module performs the increase control, based on an increase of a temperature of the exhaust gas in the increase control, the valve controlling module determines whether a protection for an exhaust system component is required, and if the protection is determined to be required, the valve controlling module shortens the overlapping period.

A control device for an internal combustion engine is provided. The control device includes an electronic control unit. The electronic control unit is configured to set a target air-fuel ratio to a rich air-fuel ratio from a time at which fuel cut control for terminating fuel supply to a combustion chamber during operation of the internal combustion engine is terminated to a time at which an output air-fuel ratio of a downstream-side air-fuel ratio sensor becomes a rich determination air-fuel ratio or lower, temporarily set the target air-fuel ratio to the rich air-fuel ratio after the output air-fuel ratio of the downstream-side air-fuel ratio sensor becomes the rich determination air-fuel ratio or lower, and thereafter set the target air-fuel ratio to a lean air-fuel ratio.

A control device for an internal combustion engine provided with a combustion control part sequentially injecting at least a primary auxiliary fuel, secondary auxiliary fuel, and main fuel from a fuel injector in predetermined operating regions, causing compressive ignition sequentially from a premix containing the primary auxiliary fuel after injection of the main fuel, and causing compressive ignition of a premix containing the main fuel using heat generated when causing compressive ignition of a premix containing the secondary auxiliary fuel, the combustion control part setting a target injection amount and target injection timing of the primary auxiliary fuel so that a peak value and a slant of a heat generation rate pattern formed by a premix containing the primary auxiliary fuel is smaller than peak values and slants of heat generation rate patterns formed by the premixes containing the secondary auxiliary fuel and the main fuel.