Abstract: A control device for an engine is provided, which includes a combustion chamber formed by a cylinder and a piston, an intake air amount adjuster that adjusts an intake air amount supplied to the combustion chamber, a controller switchable of a combustion mode between a fuel-lean first combustion mode and a stoichiometric second combustion mode based on an engine operating state, and an intake air cooler that cools the intake air supplied to the combustion chamber. The controller controls the intake air cooler to start intake air cooling in response to a request for switching the combustion modes, and after the intake air cooling is started, controls the intake air amount adjuster to start the switching of the combustion modes, and then controls the intake air cooler and the intake air amount adjuster so that the switching of the combustion modes ends after the intake air cooling is finished.

Abstract: A control device for an engine is provided, which includes a combustion chamber formed by a cylinder and a piston, an intake air amount adjuster that adjusts an intake air amount supplied to the combustion chamber, a controller switchable of a combustion mode between a fuel-lean first combustion mode and a stoichiometric second combustion mode based on an engine operating state, and an intake air cooler that cools the intake air supplied to the combustion chamber. The controller controls the intake air cooler to start intake air cooling in response to a request for switching the combustion modes, and after the intake air cooling is started, controls the intake air amount adjuster to start the switching of the combustion modes, and then controls the intake air cooler and the intake air amount adjuster so that the switching of the combustion modes ends after the intake air cooling is finished.

Abstract: An intake-air cooling system configured to cool intake air of a vehicle engine is provided, which includes an intake passage, a compressor, an evaporator, and a controller. The intake passage branches to first and second intake passages and is provided with a damper configured to change a ratio between air flow rates flowing into the first and second intake passages. The evaporator is provided to the second intake passage and cools the air flowing therethrough. When the controller does not determine that the engine driving state belongs to a knock occurring range, the controller controls the compressor so that a flow rate of refrigerant supplied to the evaporator becomes smaller within a range larger than zero, and controls the damper so that the ratio of the flow rate of the air flowing into the second intake passage becomes smaller, than a case the state belongs to the knock occurring range.

Abstract: An engine control device is provided, which includes an engine body where a cylinder is formed, an exhaust passage through which exhaust gas discharged from the engine body circulates, a NOx sensor disposed in the exhaust passage and configured to detect a concentration of NOx in the exhaust gas, an injector configured to change an air-fuel ratio inside the cylinder, an in-cylinder temperature changer configured to change a temperature inside the cylinder, and a controller configured to control the injector and the exhaust shutter valve. The controller controls the injector based on a detection value of the NOx sensor to variably set the air-fuel ratio inside the cylinder, and when a particular condition that the air-fuel ratio inside the cylinder is leaner than a preset upper limit is satisfied, and causes the in-cylinder temperature changer to raise the temperature inside the cylinder.

Abstract: A control system for a compression-ignition engine includes a combustion chamber, an injector, an ignition plug, a sensor device, and a controller having a circuitry. The ignition plug forcibly ignites mixture gas to start combustion accompanied by flame propagation of a part of the mixture gas, and again ignites remaining unburnt mixture gas at a timing at which the unburnt mixture gas combusts by self-ignition. The controller is configured to execute an ignition controlling module to output an ignition signal to the ignition plug before a target timing so that the unburnt mixture gas self-ignites at the target timing, an ignition timing estimating module to estimate an actual CI timing indicative of a timing at which the unburnt mixture gas actually self-ignited based on an in-cylinder pressure parameter, and an in-cylinder temperature determining module to determine the in-cylinder temperature at a given crank angle based on the estimated result.

Abstract: An engine control device is provided, which includes an ignition plug configured to ignite mixture gas inside a cylinder of the engine, an injector configured to change an air-fuel ratio inside the cylinder, a NOx sensor, and a controller including a processor. The controller performs a first control to control the ignition plug so that ignition is performed at a basic ignition timing or an ignition timing after the basic timing is corrected based on a combustion state of the mixture gas, and a second control to control the injector so that a NOx concentration approaches a given target value. When the ignition timing is corrected by the first control to a retarding side, the controller suspends a correction to a richer side even if the NOx concentration is a concentration at which the air-fuel ratio is corrected to the richer side by the second control.

Abstract: A premixed compression ignition engine system includes an engine, a fuel injector, a water injector, and a controller. The controller conducts: a compression-stroke mid-period injection that causes a fuel injector to inject fuel to form a fuel-air mixture in a surrounding space of a combustion chamber; a compression top-dead-center injection that causes the fuel injector to inject fuel to form a fuel-air mixture in the central space of the combustion chamber after the compression-stroke mid-period injection; and a water injection that causes a water injector to inject water to the surrounding space of the combustion chamber at a timing from commencement of the compression-stroke mid-period injection to commencement of the compression top-dead-center injection.

Abstract: An engine control device is provided, which includes an engine body where a cylinder is formed, an exhaust passage through which exhaust gas discharged from the engine body circulates, a NOx sensor disposed in the exhaust passage and configured to detect a concentration of NOx in the exhaust gas, an injector configured to change an air-fuel ratio inside the cylinder, an in-cylinder temperature changer configured to change a temperature inside the cylinder, and a controller configured to control the injector and the exhaust shutter valve. The controller controls the injector based on a detection value of the NOx sensor to variably set the air-fuel ratio inside the cylinder, and when a particular condition that the air-fuel ratio inside the cylinder is leaner than a preset upper limit is satisfied, and causes the in-cylinder temperature changer to raise the temperature inside the cylinder.

Abstract: An engine control device is provided, which includes an ignition plug configured to ignite mixture gas inside a cylinder of the engine, an injector configured to change an air-fuel ratio inside the cylinder, a NOx sensor, and a controller including a processor. The controller performs a first control to control the ignition plug so that ignition is performed at a basic ignition timing or an ignition timing after the basic timing is corrected based on a combustion state of the mixture gas, and a second control to control the injector so that a NOx concentration approaches a given target value. When the ignition timing is corrected by the first control to a retarding side, the controller suspends a correction to a richer side even if the NOx concentration is a concentration at which the air-fuel ratio is corrected to the richer side by the second control.

Abstract: A premixed compression ignition engine system includes an engine, a fuel injector, a water injector, and a controller. The controller conducts: a compression-stroke mid-period injection that causes a fuel injector to inject fuel to form a fuel-air mixture in a surrounding space of a combustion chamber; a compression top-dead-center injection that causes the fuel injector to inject fuel to form a fuel-air mixture in the central space of the combustion chamber after the compression-stroke mid-period injection; and a water injection that causes a water injector to inject water to the surrounding space of the combustion chamber at a timing from commencement of the compression-stroke mid-period injection to commencement of the compression top-dead-center injection.

Abstract: A control system for a compression-ignition engine includes a combustion chamber, an injector, an ignition plug, a sensor device, and a controller having a circuitry. The ignition plug forcibly ignites mixture gas to start combustion accompanied by flame propagation of a part of the mixture gas, and again ignites remaining unburnt mixture gas at a timing at which the unburnt mixture gas combusts by self-ignition. The controller is configured to execute an ignition controlling module to output an ignition signal to the ignition plug before a target timing so that the unburnt mixture gas self-ignites at the target timing, an ignition timing estimating module to estimate an actual CI timing indicative of a timing at which the unburnt mixture gas actually self-ignited based on an in-cylinder pressure parameter, and an in-cylinder temperature determining module to determine the in-cylinder temperature at a given crank angle based on the estimated result.

Abstract: When a predetermined restart condition is satisfied after an engine is automatically stopped, whether or not a piston of a stopped-in-compression-stroke cylinder which is in a compression stroke falls within a specific range set at a bottom dead center side of a predetermined upper limit position is determined. When the piston of the stopped-in-compression-stroke cylinder falls within the specific range, a first compression start is executed in which fuel is injected from an injector into the stopped-in-compression-stroke cylinder for the first time and is then self-ignited. In the first compression start, a start timing of a first fuel injection operation with respect to the stopped-in-compression-stroke cylinder is set to be earlier as a stop position of the piston of the cylinder gets closer to the bottom dead center within the specific range.

Abstract: An exhaust gas recirculation control device of an engine is provided. The device includes: an exhaust turbocharger having a turbine disposed in an exhaust passage and a compressor disposed in an intake passage; an intercooler disposed in the intake passage downstream of the compressor; a low-pressure EGR passage connecting the exhaust passage downstream of the turbine to the intake passage upstream of the compressor; a low-pressure EGR valve disposed in the low-pressure EGR passage and for changing a cross-sectional area thereof; a high-pressure EGR passage connecting the exhaust passage upstream of the turbine to the intake passage downstream of the intercooler; a high-pressure EGR valve disposed in the high-pressure EGR passage and for changing a cross-sectional area thereof; a valve control device for controlling openings of the low-pressure and high-pressure EGR valves; and a gear range detector for detecting a gear range of a transmission.

Abstract: An exhaust gas recirculation control device of an engine is provided. The device includes: an exhaust turbocharger having a turbine disposed in an exhaust passage and a compressor disposed in an intake passage; a low-pressure EGR passage connecting a part of the exhaust passage downstream of the turbine to a part of the intake passage upstream of the compressor; a low-pressure EGR valve disposed in the low-pressure EGR passage and for changing a cross-sectional area of the low-pressure EGR passage; an exhaust shutter valve disposed downstream of the connected part of the exhaust passage to the low-pressure EGR passage, and for changing a cross-sectional area of the exhaust passage; a valve control device for controlling openings of the low-pressure EGR valve and the exhaust shutter valve; and a gear range detector for detecting a gear range of a transmission of a vehicle in which the engine is installed.

Abstract: When a predetermined restart condition is satisfied after an engine is automatically stopped, whether or not a piston of a stopped-in-compression-stroke cylinder which is in a compression stroke falls within a specific range set at a bottom dead center side of a predetermined upper limit position is determined. When the piston of the stopped-in-compression-stroke cylinder falls within the specific range, a first compression start is executed in which fuel is injected from an injector into the stopped-in-compression-stroke cylinder for the first time and is then self-ignited. In the first compression start, a start timing of a first fuel injection operation with respect to the stopped-in-compression-stroke cylinder is set to be earlier as a stop position of the piston of the cylinder gets closer to the bottom dead center within the specific range.

Abstract: An exhaust gas recirculation control device of an engine is provided. The device includes: an exhaust turbocharger having a turbine disposed in an exhaust passage and a compressor disposed in an intake passage; a low-pressure EGR passage connecting a part of the exhaust passage downstream of the turbine to a part of the intake passage upstream of the compressor; a low-pressure EGR valve disposed in the low-pressure EGR passage and for changing a cross-sectional area of the low-pressure EGR passage; an exhaust shutter valve disposed downstream of the connected part of the exhaust passage to the low-pressure EGR passage, and for changing a cross-sectional area of the exhaust passage; a valve control device for controlling openings of the low-pressure EGR valve and the exhaust shutter valve; and a gear range detector for detecting a gear range of a transmission of a vehicle in which the engine is installed.

Abstract: An exhaust gas recirculation control device of an engine is provided. The device includes: an exhaust turbocharger having a turbine disposed in an exhaust passage and a compressor disposed in an intake passage; an intercooler disposed in the intake passage downstream of the compressor; a low-pressure EGR passage connecting the exhaust passage downstream of the turbine to the intake passage upstream of the compressor; a low-pressure EGR valve disposed in the low-pressure EGR passage and for changing a cross-sectional area thereof; a high-pressure EGR passage connecting the exhaust passage upstream of the turbine to the intake passage downstream of the intercooler; a high-pressure EGR valve disposed in the high-pressure EGR passage and for changing a cross-sectional area thereof; a valve control device for controlling openings of the low-pressure and high-pressure EGR valves; and a gear range detector for detecting a gear range of a transmission.

Abstract: An exemplary method of controlling an internal combustion engine system is described herein. The internal combustion engine system includes an internal combustion engine, a valve driving mechanism which reciprocally drives an intake valve and an exhaust valve for a combustion chamber of the internal combustion engine, a turbocharger including a turbine and a compressor, and a first EGR passage which communicates an exhaust passage downstream of the emission control device and an intake passage upstream of the compressor. The exemplary method includes shutting off supplying fuel to the combustion chamber under a predetermined condition, and decreasing a lift of the intake or exhaust valve for the combustion chamber during the shutting off supplying fuel to the combustion chamber compared to in a case of supplying fuel to said combustion chamber.