Abstract: A spark-ignition direct injection engine is provided. The engine includes an engine body, a fuel injection valve, a fuel pressure setting mechanism, an ignition plug, and a controller. The controller operates the engine to perform compression-ignition combustion within a first operating range, and controls the ignition plug to operate the engine to perform spark-ignition combustion within a second operating range. Within a specific part of the first range, the controller sets the fuel pressure to 30 MPa or above, and retards the compression ignition to after a compression top dead center by controlling the injection valve to inject fuel into a cylinder in a period from a late stage of compression stroke to an early stage of expansion stroke. Below the specific part, the controller controls the fuel injection valve to inject the fuel into the cylinder in a period from intake stroke to a mid-stage of the compression stroke.

Abstract: A spark-ignition engine is provided. The engine includes an engine body, a fuel injection valve, an ignition plug, an EGR introduction system, and a controller for operating the engine body by controlling the fuel injection valve, the ignition plug, and the EGR introduction system. The controller controls to combust mixture gas by compressing to self-ignite within a compression self-ignition combustion applying range, and to combust the mixture gas by a spark-ignition using the ignition plug within a spark-ignition combustion applying range. Substantially throughout the spark-ignition combustion applying range, the controller controls the EGR introduction system to introduce cooled EGR gas, and within the compression self-ignition applying range, the controller controls the EGR introduction system to introduce hot EGR gas. The controller controls the EGR introduction system to introduce the hot EGR gas and the cooled EGR gas within a low engine load part of the spark-ignition combustion applying range.

Abstract: A spark-ignition direct injection engine is provided. The engine includes an engine body, a fuel injection valve, a fuel pressure setting mechanism, an ignition plug, and a controller. Within a low engine speed operating range of a predetermined high engine load range, the fuel pressure setting mechanism sets a fuel pressure to 30 MPa or above, the fuel injection valve injects fuel between late stage of compression stroke and early stage of expansion stroke, and the ignition plug performs spark-ignition after the fuel injection completes. Within a high engine speed operating range of the high engine load range, the fuel injection valve injects fuel between intake stroke to mid-stage of compression stroke, and the ignition plug performs the spark-ignition. The ignition timing is changed according to an octane number, the changing width of the ignition timing is shorter within the low engine speed range than the high engine speed range.

Abstract: The disclosure provides a control device of a spark-ignition gasoline engine. When an operating state of an engine body is within a low engine speed range, a controller operates a fuel pressure variable mechanism so that a fuel pressure is higher within a high engine load range compared to a low engine load range, the controller operates, within the high engine load range, a fuel injection mechanism to perform at least a fuel injection into the cylinder by a cylinder internal injection valve at a timing during a retard period from a late stage of a compression stroke to an early stage of an expansion stroke, and the controller operates, within the high engine load range, an ignition plug to ignite at a timing during the retard period and after the fuel injection.

Abstract: A supercharged engine has a geometric compression ratio ser to 16 or more and is designed to perform a compression self-ignition combustion under an air-fuel ratio leaner than a stoichiometric air-fuel ratio at least in a low engine speed range. On a lower engine load side than a given engine load within an engine operating region at which the compression self-ignition combustion is performed, a fresh air amount is reduced and an effective compression ratio (??) is increased, as compared with a higher engine load side than the given engine load within the engine operating region, and, on the higher engine load side than the given engine load, a supercharging pressure based on a supercharger (25) is increased to increase the fresh air amount, and the effective compression ratio (??) is reduced, as compared with the lower engine load side than the given engine load.

Abstract: In a specified operating area including a low engine-speed and low engine-load area, an excess air ratio ? is set at a specified ratio which is two or greater and three or smaller and an ignition timing ?ig of a spark plug is set at a timing of MBT to provide the maximum torque as a normal combustion control (S4). In case a catalyst temperature Tc is lower than a predetermined first temperature T1 in this area, a control of retarding the ignition timing from the MBT timing and/or a control of decreasing the excess air ratio ? to a ration below the above-described ratio are executed (S6, S8, S9). Accordingly, the temperature of the catalyst can be prevented simply and effectively from decreasing excessively, maintaining combustion conditions to provide a properly high thermal efficiency.

Abstract: The disclosure provides a control device of a spark-ignition gasoline engine. When an operating state of an engine body is within a low engine speed range, a controller operates a fuel pressure variable mechanism so that a fuel pressure is higher within a high engine load range compared to a low engine load range, the controller operates, within the high engine load range, a fuel injection mechanism to perform at least a fuel injection into the cylinder by a cylinder internal injection valve at a timing during a retard period from a late stage of a compression stroke to an early stage of an expansion stroke, and the controller operates, within the high engine load range, an ignition plug to ignite at a timing during the retard period and after the fuel injection.

Abstract: The disclosure provides a control device of a spark-ignition gasoline engine. When an operating state of an engine body is within a low engine speed range, a controller controls a fuel pressure variable mechanism so that a fuel pressure is higher within a high engine load range compared to a low engine load range, the controller operates, within the high engine load range, a fuel injection valve to perform a fuel injection at least at a timing that is more retarded than an injection timing of a fuel within the low engine load range and is within a retard period from a late stage of a compression stroke to an early stage of an expansion stroke, and the controller operates, within the high engine load range, an ignition plug to ignite at a timing within the retard period and further after the fuel injection.

Abstract: A control device of a spark-ignition gasoline engine is provided. The control device includes a controller for operating the engine body by controlling at least a fuel injection valve, an ignition plug, and a fuel pressure variable mechanism. Depending on the engine load range, the controller sets the combustion mode to a compression-ignition mode or a spark-ignition mode. In each mode, the controller also controls the fuel pressure, and the timing of fuel injection and ignition. The controller may also performs external EGR control in each mode.

Abstract: An engine is designed to allow a compression self-ignition combustion under an air-fuel ratio leaner than a stoichiometric air-fuel ratio to be performed at least in a partial-load range of the engine. Under a condition that an engine speed varies at a same load in an engine operating region of the compression self-ignition combustion, a compression end temperature Tx, which is an in-cylinder temperature just before an air-fuel mixture self-ignites, is controlled to be raised higher in a higher engine speed side than in a lower engine speed side. As one example of control for the compression end temperature Tx, an internal EGR amount is controlled to be increased larger in the higher engine speed side than in the lower engine speed side, to raise a compression initial temperature T0 which is an in-cylinder temperature at a start timing of a compression stroke.

Abstract: A supercharged engine has a geometric compression ratio ser to 16 or more and is designed to perform a compression self-ignition combustion under an air-fuel ratio leaner than a stoichiometric air-fuel ratio at least in a low engine speed range. On a lower engine load side than a given engine load within an engine operating region at which the compression self-ignition combustion is performed, a fresh air amount is reduced and an effective compression ratio (??) is increased, as compared with a higher engine load side than the given engine load within the engine operating region, and, on the higher engine load side than the given engine load, a supercharging pressure based on a supercharger (25) is increased to increase the fresh air amount, and the effective compression ratio (??) is reduced, as compared with the lower engine load side than the given engine load.

Abstract: In a specified operating area including a low engine-speed and low engine-load area, an excess air ratio ? is set at a specified ratio which is two or greater and three or smaller and an ignition timing ?ig of a spark plug is set at a timing of MBT to provide the maximum torque as a normal combustion control (S4). In case a catalyst temperature Tc is lower than a predetermined first temperature T1 in this area, a control of retarding the ignition timing from the MBT timing and/or a control of decreasing the excess air ratio ? to a ration below the above-described ratio are executed (S6, S8, S9). Accordingly, the temperature of the catalyst can be prevented simply and effectively from decreasing excessively, maintaining combustion conditions to provide a properly high thermal efficiency.

Abstract: A fuel control unit and a fuel injection control method for a multi-cylinder engine adjust the pulse width of asynchronous injection so as to set the air-fuel ratio of a fuel-air mixture in a first cylinder to 17 or more but under 21 if it is determined according to an engine speed (Ne) that an engine is in an idling mode and if it is determined according to the opening of a throttle valve that a condition for starting the acceleration of the engine has been satisfied. The foregoing first cylinder is the cylinder in which compression pressure increases first following the determination described above.