A vehicular internal combustion engine system includes an internal combustion engine and an electric intake air supply device. The internal combustion engine is shifted into a stoichiometric combustion mode, and a lean combustion mode. The electric intake air supply device is driven by an on-vehicle battery, and employed to contribute a part of intake air quantity at least under a specific operating condition when in the lean combustion mode. A control method includes: determining a requested electric energy of the electric intake air supply device for a shift into the lean combustion mode in response to a shift from a stoichiometric combustion operation region into a lean combustion operation region; and continuing the stoichiometric combustion mode, without operation of the electric intake air supply device, when the on-vehicle battery is in an insufficient state of charge with respect to the requested electric energy.

When a start request for an internal combustion engine is made with 1) a clutch disconnected, 2) a crankshaft rotating at a specified rotation speed or greater, and 3) fuel injection by an injector stopped, a controller for a vehicle executes: a first process that identifies, from the cylinders, a target cylinder that is in a compression stroke when the request is made; a second process that calculates a requested injection position based on the rotation speed; a third process that calculates, as a start crank position, a rotation position of the crankshaft advanced from the requested injection position by a specified rotation amount; and a fourth process that outputs a command signal that instructs a target injector to inject fuel at the crank position only if the rotation position of the crankshaft obtained when the request is made is advanced from the crank position.

A control unit performs a vehicle attitude control to reduce a torque generated by an engine when an increase in a steering angle exceeds a standard increase, and a spark ignition controlled compression ignition combustion in a predetermined operating range. In the spark ignition controlled compression ignition combustion, switching of an air-fuel ratio mode is performed between a first air-fuel ratio mode (λ>1) is formed and a second air-fuel ratio mode (in which a mixed gas of λ≤1) is formed. If the switching of the air-fuel ratio mode is requested without the vehicle attitude control, the control unit allows performing the requested switching of the air-fuel ratio mode. In contrast, if the mode switching is requested in a state where the vehicle attitude control is requested, the control unit disallows switching of the air-fuel ratio mode even when the switching of the air-fuel ratio mode is requested.

A controller executes a first restarting process when restarting of an engine is requested under a condition where an engine speed is less than a determination speed. In the first restarting process, cranking of the engine is performed by a motor generator in a state in which the motor generator is connected to a crankshaft through engagement of a clutch, and fuel injection and ignition are initiated in the engine when a combustion initiation condition is satisfied in this state. The controller executes a second restarting process when restarting of the engine is requested under a condition where the engine speed is greater than or equal to the determination speed. In the second restarting process, fuel injection and ignition are initiated in the engine, and the motor generator is connected to the crankshaft through engagement of the clutch after the engine has been restarted.

Systems and methods are provided for determining and correcting air/fuel imbalance between cylinders of an internal combustion engine. A deactivation strategy is determined and implemented. An evaluation is made of whether the engine is operating with an air/fuel imbalance between cylinders. When an imbalance is identified, an alternate deactivation strategy is implemented. Based on outcomes of the alternate deactivation strategy, a source cylinder of the air/fuel imbalance is identified, and fuel flow to the source cylinder is corrected.

An engine system is provided, which includes a vehicle-mounted engine having an injector, a spark plug, and a property adjusting device, an accelerator opening sensor, and a controller. The controller performs a combustion control for controlling the injector, the spark plug, and the property adjusting device so that a target torque set based on a present accelerator opening detected by the accelerator opening sensor is outputted in a specific cycle in the future from a present time by a given delay time. In the combustion control, the controller sets a target load of the engine in the specific cycle based on the present accelerator opening, and sets a combustion transition from the present cycle to the specific cycle by selecting beforehand combustion from the present cycle to the specific cycle, from flame propagation combustion and compressed self-ignition combustion, based on the set target load.

A method of controlling an engine is provided, which includes setting, by a controller, a target torque of the engine in a specific cycle in the future by a given delay time from the present time based on a present accelerator opening. The method includes selecting beforehand, by the controller, combustion in the specific cycle according to the target torque, from flame propagation combustion and compressed self-ignition combustion. The method includes outputting, by the controller, a control signal to a property adjusting device before the specific cycle so that a property inside the cylinder in the specific cycle becomes a property corresponding to the selected combustion. The method includes estimating, by the controller, the property at a timing when an intake valve is closed in the specific cycle. The method includes outputting, by the controller, a control signal corresponding to the estimated property to a spark plug or an injector.

A control device is applied to an internal combustion engine equipped with an electric heating catalyst system provided with an EHC. The control device executes a preheating process to warm up an exhaust gas reduction catalyst prior to a start of the internal combustion engine by supplying electric power to the EHC, when the control device determines that a temperature of the exhaust gas reduction catalyst is lower than an activation temperature. The control device executes a determination process for determining whether water is adhered to a catalyst carrier. The control device starts the internal combustion engine without executing the preheating process when the control device determines by the determination process that water is adhered to the catalyst carrier, even when the control device determines that the temperature of the exhaust gas reduction catalyst is lower than the activation temperature.

During a predetermined operation state in which the opening degree of a throttle valve is fixed, an air flow meter positioned more on the upstream side than a pressure control valve detects a first intake air amount when the opening degree of the pressure control valve positioned on the upstream side of the throttle valve is set to a predetermined first valve opening degree and a second intake air amount when the opening degree of the pressure control valve is set to a predetermined second valve opening degree smaller than the first valve opening degree. On the basis of the first intake air amount and the second intake air amount, a diagnosis is made regarding whether there is an abnormality in a first pipe, a second pipe, a third pipe and the like which are included in a blow-by gas recirculation system for blow-by gas treatment.

A fuel injection control method for an internal combustion engine is provided. The internal combustion engine includes a fuel pump (38) that pressure-feeds fuel, a fuel injection valve (19) that injects the fuel pressure-fed by the fuel pump directly into a cylinder of the internal combustion engine (1), and a fuel pressure detection device (45) that detects a pressure of the fuel pressure-fed by the fuel pump. The fuel injection control method executes a first smoothing process (S3) of performing a smoothing process on a detected fuel pressure by first smoothing, a second smoothing process (S4) of performing a smoothing process on the detected fuel pressure by second smoothing different from the first smoothing, and a selection process (S5) of selecting, based on an operating state of the internal combustion engine, whether to execute fuel injection control (S6, S7) based on a first detected fuel pressure smoothed by the first smoothing process or fuel injection control (S8, S9) based on a second detected fuel pressure smoothed by the second smoothing process.