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 system of an engine mounted on a vehicle where a cabin is air-conditioned by an air conditioner, is provided. A heat exchanger of an evaporator of the air conditioner is divided into a first heat exchanger and a second heat exchanger that are mutually independent, and an air passage includes a first division passage and a second division passage. The intake system cools intake air utilizing a part of the air conditioner, and includes a connecting passage that guides first air cooled by passing through the first heat exchanger, a passage switch, and a controller. When the controller determines that a cooling demand for the intake air exists, it controls the first air to flow into an intake passage through the connecting passage, and when the controller determines that there is no cooling demand, it controls the first air to flow into the first division passage.

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 system of an engine mounted on a vehicle where a cabin is air-conditioned by an air conditioner, is provided. A heat exchanger of an evaporator of the air conditioner is divided into a first heat exchanger and a second heat exchanger that are mutually independent, and an air passage includes a first division passage and a second division passage. The intake system cools intake air utilizing a part of the air conditioner, and includes a connecting passage that guides first air cooled by passing through the first heat exchanger, a passage switch, and a controller. When the controller determines that a cooling demand for the intake air exists, it controls the first air to flow into an intake passage through the connecting passage, and when the controller determines that there is no cooling demand, it controls the first air to flow into the first division passage.

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: A direct injection engine includes a fuel injection valve configured to inject fuel into a cylinder, a water injection valve configured to inject water into the cylinder, and a valve variable mechanism configured to change an operation timing of each of an intake valve and an exhaust valve. During an operation in a low load range, a negative overlap period when both of the intake valve and the exhaust valve are closed across an exhaust top dead center is formed by the valve variable mechanism, and fuel is injected from the fuel injection valve and water is injected from the water injection valve respectively during the negative overlap period. This causes a steam reforming reaction such that at least a part of injected fuel and injected water turns to hydrogen and carbon monoxide within the cylinder during the negative overlap period.

Abstract: A homogeneous charge compression ignition engine includes a cylinder configured to accommodate a piston to be reciprocally movable, a fuel injection valve configured to inject fuel into the cylinder, a water injection valve configured to inject water into the cylinder, a fuel injection control module configured to inject fuel from the fuel injection valve into the cylinder at such a timing that a mixture of fuel and air is self-ignited in a latter stage of a compression stroke or in an initial stage of an expansion stroke, and a water injection control module configured to perform at least a basic water injection of injecting water from the water injection valve into the cylinder during a predetermined period, which starts concurrently with or after start of combustion by the self-ignition and which overlaps a combustion period.

Abstract: A fuel injection valve is provided for a ceiling portion of a cylinder head. A tip of an ignition electrode is arranged in the vicinity of an injection tip of the fuel injection valve. A recess is provided for the ceiling portion. A center of a cavity is shifted with respect to a bore center of the cylinder. In a vertical cross-section of the inside of a combustion chamber taken along a plane passing through the injection tip of the fuel injection valve and the tip of the ignition electrode, a distance from the injection tip to a wall surface of the cavity at a side at which the ignition electrode is provided is longer than a distance from the injection tip to a wall surface of the cavity at an opposite side.

Abstract: A fuel injection valve is shifted, with respect to the bore center of a cylinder, toward one end of an engine's output shaft. A top surface of a piston has inclined surfaces, and is raised by the inclined surfaces. A cavity is formed by hollowing out portions of the inclined surfaces, and faces the injection axis of the fuel injection valve. In a vertical cross section taken along the plane passing through a particular location in an intake other-side region of a combustion chamber and the location of the fuel injection valve, the distance from an injection tip of the fuel injection valve to the wall surface of the cavity at the particular location is longer than that from the injection tip to the wall surface at a diametrically opposed location to the particular location.

Abstract: A fuel injection valve is shifted, with respect to the bore center of a cylinder, toward one end of an engine's output shaft. A top surface of a piston has inclined surfaces, and is raised by the inclined surfaces. A cavity is formed by hollowing out portions of the inclined surfaces, and faces the injection axis of the fuel injection valve. In a vertical cross section taken along the plane passing through a particular location in an intake other-side region of a combustion chamber and the location of the fuel injection valve, the distance from an injection tip of the fuel injection valve to the wall surface of the cavity at the particular location is longer than that from the injection tip to the wall surface at a diametrically opposed location to the particular location.

Abstract: A direct injection engine includes a fuel injection valve configured to inject fuel into a cylinder, a water injection valve configured to inject water into the cylinder, and a valve variable mechanism configured to change an operation timing of each of an intake valve and an exhaust valve. During an operation in a low load range, a negative overlap period when both of the intake valve and the exhaust valve are closed across an exhaust top dead center is formed by the valve variable mechanism, and fuel is injected from the fuel injection valve and water is injected from the water injection valve respectively during the negative overlap period. This causes a steam reforming reaction such that at least a part of injected fuel and injected water turns to hydrogen and carbon monoxide within the cylinder during the negative overlap period.

Abstract: A homogeneous charge compression ignition engine includes a cylinder configured to accommodate a piston to be reciprocally movable, a fuel injection valve configured to inject fuel into the cylinder, a water injection valve configured to inject water into the cylinder, a fuel injection control module configured to inject fuel from the fuel injection valve into the cylinder at such a timing that a mixture of fuel and air is self-ignited in a latter stage of a compression stroke or in an initial stage of an expansion stroke, and a water injection control module configured to perform at least a basic water injection of injecting water from the water injection valve into the cylinder during a predetermined period, which starts concurrently with or after start of combustion by the self-ignition and which overlaps a combustion period.

Abstract: A fuel injection valve is provided for a ceiling portion of a cylinder head. A tip of an ignition electrode is arranged in the vicinity of an injection tip of the fuel injection valve. A recess is provided for the ceiling portion. A center of a cavity is shifted with respect to a bore center of the cylinder. In a vertical cross-section of the inside of a combustion chamber taken along a plane passing through the injection tip of the fuel injection valve and the tip of the ignition electrode, a distance from the injection tip to a wall surface of the cavity at a side at which the ignition electrode is provided is longer than a distance from the injection tip to a wall surface of the cavity at an opposite side.

Abstract: A direct injection engine includes an ignition assistance section applying energy to fuel injected into a cylinder using an injector to assist auto-ignition combustion of the fuel when the engine is within an auto-ignition combustion operation range. A start time of fuel injection is set within a period from a terminal stage of a compression stroke to a compression top dead center. The energy is applied to the fuel injected into the cylinder in a period from start of the fuel injection to an initial stage of an expansion stroke such that a time of a specific crank angle when an increase rate of in-cylinder pressure, which is a ratio of a change in the in-cylinder pressure to a change in a crank angle in motoring the engine, reaches a negative maximum value overlaps a combustion period when a combustion mass percentage of the fuel ranges from 10% to 90%.

Abstract: A direct injection engine includes an ignition assistance section applying energy to fuel injected into a cylinder using an injector to assist auto-ignition combustion of the fuel when the engine is within an auto-ignition combustion operation range. A start time of fuel injection is set within a period from a terminal stage of a compression stroke to a compression top dead center. The energy is applied to the fuel injected into the cylinder in a period from start of the fuel injection to an initial stage of an expansion stroke such that a time of a specific crank angle when an increase rate of in-cylinder pressure, which is a ratio of a change in the in-cylinder pressure to a change in a crank angle in motoring the engine, reaches a negative maximum value overlaps a combustion period when a combustion mass percentage of the fuel ranges from 10% to 90%.

Abstract: A valve overlap period is increased as a desired torque of an engine increases by advancing an opening timing of an intake valve at a rate greater than that of retarding a closing timing of an exhaust valve in a low engine-torque area in which the desired torque of the internal combustion engine is relatively low (step S16). The valve overlap period is increased as the desired torque of the engine increases by retarding the closing timing of the exhaust valve at a rate greater than that of advancing the opening timing of the intake valve in a high engine-torque area in which the desired torque of the internal combustion engine is relatively high (step S17). Accordingly, the drivability can be improved by obtaining the proper torque and the smooth torque curve in the wide driving area.

Abstract: A valve overlap period is increased as a desired torque of an engine increases by advancing an opening timing of an intake valve at a rate greater than that of retarding a closing timing of an exhaust valve in a low engine-torque area in which the desired torque of the internal combustion engine is relatively low (step S16). The valve overlap period is increased as the desired torque of the engine increases by retarding the closing timing of the exhaust valve at a rate greater than that of advancing the opening timing of the intake valve in a high engine-torque area in which the desired torque of the internal combustion engine is relatively high (step S17). Accordingly, the drivability can be improved by obtaining the proper torque and the smooth torque curve in the wide driving area.