A control system includes a processor for controlling an internal combustion engine having a temperature region, wherein a change of ignition delay time accompanying a rise in a cylinder temperature when the cylinder temperature is in the temperature region is smaller than when the cylinder temperature is out of the temperature region. When a self ignition timing of secondary fuel is earlier than a self ignition timing of primary fuel due to the secondary fuel being injected at a crank angle at which the cylinder temperature is higher than the temperature region, the processor controls a ratio of the secondary fuel to be lower than when the self ignition timing of the secondary fuel is later than the self ignition timing of the primary fuel due to the secondary fuel being injected at a crank angle at which the cylinder temperature is within the temperature region.

An engine system is provided, which includes an engine, a swirl control valve, an EGR passage, an EGR gas adjusting mechanism, and a controller. The engine includes a cylinder, a piston, and a fuel injection valve. The swirl control valve is provided inside an intake passage and generates a swirl flow inside the cylinder when it closes. When an engine load is at or below a given threshold, the controller controls the swirl control valve to close. While the engine load is the threshold or below, the controller controls the EGR gas adjusting mechanism such that, at a fixed engine speed, an increase rate of an EGR gas amount with respect to an increase in the engine load is lower in a first load range than in a second load range, the first load range being on a higher load side of the second load range and including the threshold.

An engine system capable of controlling an intake air flow includes a combustion chamber, an ignition plug, an intake air flow control valve, and a controller. The controller performs, in at least a part of an operating range, SPCCI combustion in which after jump-spark ignition combustion of a portion of a mixture gas inside the combustion chamber by a jump-spark ignition of the ignition plug, compression ignition combustion of the remaining mixture gas is carried out by a self-ignition. The controller strengthens, at least in a part of the operating range of SPCCI combustion, the intake air flow inside the combustion chamber by controlling the intake air flow control valve. The controller controls, in a middle-load range of the operating range where SPCCI combustion is performed, the intake air flow control valve so that the intake air flow becomes weaker than in a high-load range and a low-load range.

An engine system is provided, including an engine, a circulation system that circulates coolant through a water jacket, and a controller. The circulation system includes a radiator passage including a heat exchanger, a bypass passage, a flow rate control device, and a thermally-actuated valve. The engine has a spark plug that forcibly ignites an air-fuel mixture. The engine switches between a first combustion in which the air-fuel mixture combusts without the forcible ignition, and a second combustion in which the air-fuel mixture combusts by the forcible ignition. The controller is electrically connected to the flow rate control device, and when the engine performs the first combustion, the controller controls the flow rate control device to adjust the flow rate of the coolant flowing through the water jacket according to the engine load, by closing the radiator passage and adjusting the flow rate of the coolant flowing through the bypass passage.

An engine control apparatus includes an ignition control section and an injection control section. When partial compression ignition combustion is carried out, the ignition control section causes an ignition plug to carry out: main ignition in which a spark is generated in a late period of a compression stroke or an initial period of an expansion stroke to initiate the SI combustion; and preceding ignition in which the spark is generated at earlier timing than the main ignition. Also, when the partial compression ignition combustion is carried out, the injection control section causes the injector to inject fuel at such timing that the fuel exists in a cylinder at an earlier time point than the preceding ignition. Energy of the preceding ignition is set to be higher when an engine speed is high than when the engine speed is low.

Provided is an ignition control section and an injection control section. When partial compression ignition combustion is carried out, the ignition control section causes an ignition plug to carry out: main ignition in which a spark is generated in a late period of a compression stroke or an initial period of an expansion stroke to initiate SI combustion; and preceding ignition in which the spark is generated at earlier timing than the main ignition. Also, when the partial compression ignition combustion is carried out, the injection control section causes an injector to inject fuel at such timing that the fuel exists in a cylinder at an earlier time point than the preceding ignition. Ignition timing of the preceding ignition is set to be more retarded when an in-cylinder pressure specified by an in-cylinder pressure specification section is high than when the in-cylinder pressure is low.

An engine control apparatus includes an ignition control section and an injection control section. When the partial compression ignition combustion is carried out, the ignition control section causes an ignition plug to carry out: main ignition in which a spark is generated in a late period of a compression stroke or an initial period of a expansion stroke to initiate the SI combustion; and preceding ignition in which the spark is generated at earlier timing than the main ignition. Also, when the partial compression ignition combustion is carried out, the injection control section causes the injector to inject fuel at such timing that the fuel exists in a cylinder at an earlier time point than the preceding ignition. The energy of the preceding ignition is set to be higher when the in-cylinder pressure specified by the in-cylinder pressure specification section is high than when the in-cylinder pressure is low.

The control apparatus for a compression ignition type engine includes a plurality of cylinder inner pressure sensors that detect pressure in each cylinder, and a combustion control unit. The combustion control unit corrects a target fuel injection amount of each cylinder by an injector based on a deviation between a predicted combustion period that is a period from an ignition timing by an ignition plug to a predetermined mass combustion timing and that is obtained based on a preset combustion model, and an actual combustion period that is a period from the ignition timing by the ignition plug to an actual combustion timing and that is obtained based on cylinder inner pressure, such that the period from the ignition timing by the ignition plug to the predetermined mass combustion timing, which is the timing when fuel having a predetermined mass ratio combusts, is equalized in each cylinder.

An engine system is provided, which includes a supercharger driven by a crankshaft of an engine, an electromagnetic clutch disconnectably connecting the crankshaft to the supercharger, and a controller configured to output a control signal to the electromagnetic clutch. The controller includes a processor configured to execute an uphill-angle detecting module to detect an uphill angle during traveling of a vehicle, an uphill determining module to determine whether the detected uphill angle is above a given first uphill angle, and a boost controlling module to, when the detected uphill angle is above the first uphill angle, control the electromagnetic clutch to connect the crankshaft to the supercharger even when a target torque of the engine is within a not-boosting range.

An engine system provided to a vehicle having an accelerator pedal is provided. When an engine operation range is determined to shift to a first range (where an electromagnetic clutch is disengaged) from a second range (where the clutch is engaged) after an opening of the accelerator pedal increases at a rate below a given reference rate, the clutch is switched from ON to OFF after a given basic stand-by period passes from the shift. When the engine operation range is determined to shift from the second range to the first range after the accelerator pedal opening increases at the given reference rate or above, the clutch is switched from ON to OFF after a given acceleration stand-by period (longer than the basic stand-by period by a given added period) passes from the shift.