Abstract: An engine includes a cylinder block, a cylinder head, and a piston. The cylinder head is connected to the cylinder block. The piston is movably connected to the cylinder block. The cylinder block, the cylinder head, and the piston form a combustion chamber. The cylinder head includes an intake valve hole and an exhaust valve hole. An intake valve is disposed at the intake valve hole and an exhaust valve is disposed at the exhaust valve hole. A barrier protrusion is protruded at the edge of the intake valve hole away from the exhaust valve hole. The included angle between a first connecting line connecting a first end of the barrier protrusion and a center of the intake valve hole and a second connecting line connecting a second end of the barrier protrusion and the center of the intake valve hole is greater than 120 degrees and less than or equal to 180 degrees.

Abstract: The present invention relates to a gas intake pipe (2) for a cylinder of a thermal engine. The pipe comprises means for diverting the gas so as to generate a tumble type aerodynamic motion of the gas within the cylinder. The diversion means comprise at least a “ramp” shape (6) on the lower profile (12) of the pipe and a concave zone on the upper profile (10) of intake pipe (2).

Abstract: Apparatus for controlling valve timing in an internal combustion engine locates a first valve port in a first side of the engine cylinder and a second valve port in a second side of the engine cylinder. A first rotating valve disc and a second rotating valve disc are respectively disposed next to the first and second valve port. Each rotating valve disc includes a valve port. Each disc rotates in synchronism with the crankshaft to align its' port with the respective first and second valve ports. A variety of intake devices coupled to the first rotating valve disc control intake air flow into the engine cylinder, and a variety of exhaust devices coupled to the second rotating valve disc control exhaust gas flow from the engine cylinder.

Abstract: Assume that a boundary on the air-fuel ration operation is changed from a boundary (i) to a boundary (ii). Then, after the boundary is changed, a high EGR operation region where a target EGR rate is set to a high value overlaps partially with a rich operation region. Therefore, when it is determined that the current operating point exists in the overlapped region, the target EGR rate is forcibly lowered. In addition, the boundary on a drive cam for an intake valve is changed from a boundary (I) to a boundary (II) thereby a region where a small cam is selected is enlarged.

Abstract: A method and system of periodically cycling an air shutoff valve, upon a pre-determined length of time elapsing since the last valve cycle; or upon the cumulative run time of an engine since the last valve cycle exceeding a pre-determined value.

Abstract: A fuel amount distribution method is provided to distribute fuel to a plurality of injectors on each of multiple cylinders of an engine with a dual injector. The fuel amount distribution method includes performing, by a controller, a single injection operation in which a single injector of the plurality of injectors constituting the dual injector injects fuel into a corresponding cylinder when a required fuel injection time of the dual injector of at least one cylinder of the multiple cylinders is less than a minimum injection time of each injector of the plurality of injectors of the dual injector. Thereby, precise air-fuel control in a low fuel rate section is achieved.

Abstract: A method of controlling an engine includes initiating a transition from homogenous charge compression ignition (HCCI) to spark ignited (SI) combustion mode of the engine under low load. The method includes commanding an exhaust valve actuator to increase lift of the exhaust valve to maximize expulsion of combustion chamber contents. The method also includes injecting into the combustion chamber sufficient amount of fuel after the lift of the exhaust valve was increased to generate substantially stoichiometric air-fuel ratio of the gas mixture contained in the chamber. The method also includes igniting the gas mixture after the fuel was injected into the combustion chamber to maximize combustion of the gas mixture. The method additionally includes commanding an intake camshaft phaser to change the position of the intake camshaft to a position configured for predetermined throttled SI combustion mode after the gas mixture was ignited to maximize operating efficiency of the engine.

Abstract: A four-stroke engine includes a cylinder head in which a combustion chamber, an intake port that communicates with the combustion chamber, and a housing hole that passes through the combustion chamber and through the intake port are provided, and a fuel injector that supplies a mist of fuel directly to the combustion chamber by jetting the mist of fuel toward the combustion chamber. The fuel injector includes at least a portion that is disposed at the intake port and at the housing hole.

Abstract: Methods and systems are provided for operating an engine including a first and a second bank of cylinders. One example method comprises, adjusting engine injection timing based on a first temperature of a first intake of the first bank and a second temperature of a second intake of the second bank.

Abstract: Systems and methods for operating a twin scroll turbocharged engine with a junction configured to selectively control exhaust gas delivery to an exhaust gas recirculation system and a twin scroll turbine are provided.

Abstract: Provided is a spark-ignition internal combustion engine capable of ensuring engine output power while setting a geometric compression ratio of an engine body to a high value. In the spark-ignition internal combustion engine, each of a clearance between a top surface (3a) of a piston (3) located at a top dead center position and a lower surface (8a) of each of two intake valves (8) in a full-closed state, and a clearance between the top surface (3a) of the piston (3) located at the top dead center position and a lower surface (9a) of each of two exhaust valves (9) in a full-closed state, is set to 5 mm or more, and a stroke length S of the piston (3) is set to satisfy the following relation: S?0.977×B+18.2, where B is a bore diameter of a cylinder.

Abstract: The present invention relates to a fuel injection control apparatus for controlling fuel injection and a method therefor in an engine having first and second intake passages provided with first and second fuel injection valves, respectively. Fuel injection modes using the two injection valves include an alternative injection mode in which the first and second fuel injection valves are alternately operated every predetermined number of cycles and a combined injection mode in which both the first and second fuel injection valves are used for each cycle. Then, the combined injection mode is selected in a full load range. In a partial load range, the alternative injection mode is selected in a cold state and the combined injection mode is selected after warm-up. Accordingly, it is possible to reduce an equilibrium amount of adhering fuel to an inner wall of an intake passage.

Abstract: A system in an internal combustion engine is provided. The system a combustion chamber, a first exhaust port in fluidic communication with the combustion chamber, a second exhaust port in fluidic communication with the combustion chamber, and a direct fuel injector positioned between the first and second exhaust port and fluidly communicating directly with the combustion chamber.

Abstract: An engine assembly may include an engine block, a first piston, a second piston, and a cylinder head. The cylinder head and the engine block may define a first combustion chamber and a second combustion chamber. The cylinder head may define a first intake port and a second intake port. The first intake port may be in communication with the first combustion chamber and may include a first inlet extending through an upper surface of the cylinder head. The second intake port may be in communication with the second combustion chamber and may include a second inlet extending through a side of the cylinder head.

Abstract: An engine system comprises an air cleaner, a combustion chamber coupled to an intake port, and an intake manifold. The intake manifold is configured to receive air from the air cleaner, and, under some conditions to receive exhaust from the combustion chamber. The engine system further comprises a multifunction, barrel-type throttle valve coupled to the intake port via an outlet, the throttle valve having a first inlet coupled to the intake manifold and a second inlet coupled to the air cleaner.

Abstract: The invention relates to a device for distributing the incoming gases in an internal combustion air supply system. This system comprises a fresh air intake pipe (1) and an exhaust gas recirculation intake pipe (2) and the internal combustion engine comprises, for each cylinder, a cylinder head that forms a lid over it, at least one inlet gas intake valve (3, 4) and at least one exhaust valve (5) which are mounted in the cylinder head and, in the case of a multi-cylinder engine, a distributor (7) connecting at least the fresh air intake pipe (1) to the cylinders. In this device, the fresh air intake pipe (1) and the exhaust gas recirculation intake pipe (2) are connected to each of the cylinders independently of one another, each of them (1, 2) via an intake valve (3, 4) dedicated to it (1, 2).

Abstract: A combustion system for a vehicle may include a piston in which a first combustion recess is formed in an upper end surface thereof, and at least one second combustion recess is further formed at the bottom of the first combustion recess, a first intake port and a second intake port for supplying a cylinder with air, and a controller that differently controls amounts of recirculation exhaust gas being supplied to the first intake port and the second intake port.

Abstract: Provided is a spark-ignition internal combustion engine capable of ensuring engine output power while setting a geometric compression ratio of an engine body to a high value. In the spark-ignition internal combustion engine, each of a clearance between a top surface (3a) of a piston (3) located at a top dead center position and a lower surface (8a) of each of two intake valves (8) in a full-closed state, and a clearance between the top surface (3a) of the piston (3) located at the top dead center position and a lower surface (9a) of each of two exhaust valves (9) in a full-closed state, is set to 5 mm or more, and a stroke length S of the piston (3) is set to satisfy the following relation: S?0.977×B+18.2, where B is a bore diameter of a cylinder.

Abstract: An intake throttle valve is located in an intake passage upstream of first and second intake ports, such that intake air flows into mainly the first intake port to generate a swirl flow when an opening degree of the intake throttle valve is not larger than a predetermined value, and flows into both the first and second intake ports when the opening degree thereof is larger than the predetermined value. Furthermore, first and second fuel injection valves for respectively injecting fuel to the first and second intake ports are controlled to inject fuel from the first fuel injection valve when the opening degree of the intake throttle valve is not larger than about the predetermined value, and to inject fuel from both the first fuel injection valve and the second fuel injection valve when the opening degree of the intake throttle valve is larger than about the predetermined value.

Abstract: A valve (10) is described for use in oil injection of an oil mist (8) for lubricating/flushing cylinders in large engines and arranged with mounting means (14) for fastening in a cylinder wall (2) with a valve stem (12, 13) extending through the cylinder wall and with a nozzle outlet (6) at the inner end of the valve stem. A valve is made, the spray direction of which may be adjusted after mounting. Therefore, the valve is peculiar in that the nozzle outlet (6) is disposed in the inner valve stem part (13) which is rotatable relative to an outer valve stem part (12) . The outer valve stem part (12) is fastened to or made as an integral part of the mounting means (14).

Abstract: A method of operating an engine having at least one cylinder, the method comprising of directing a first air stream to an intake valve of the cylinder; directing a second, separate air stream to a second intake valve of the cylinder, said second air stream at a higher temperature than said first air stream; operating said first intake valve and adjusting at least one of an opening timing and a closing timing of said first intake valve to adjust engine output; and intermittently operating said second intake valve to maintain said higher temperature of said second air stream.

Abstract: When a homogeneous combustion is to be executed at a lean air-fuel ratio, a tumbling flow that whirls in the cylinder descending in the cylinder bore on the exhaust valve side and ascending in the cylinder bore on the intake valve side, is intensified by the fuel that is injected from the fuel injection valve toward the exhaust valve side in the cylinder bore in the last stage of the intake stroke.

Abstract: In a vehicle incorporating an internal combustion engine having in-cylinder injectors and intake manifold injectors and performing engine intermittent operation control, at the end of vehicle operation, the fuel pressure is decreased in both a high-pressure delivery pipe and a low-pressure delivery pipe by actuation (opening) of an electromagnetic relief valve and by stop of operation of a low-pressure fuel pump. This prevents deterioration in emission performance at the next engine start attributable to fuel leakage due to degradation in oil tightness of the injectors during the operation stop period. When the engine is temporarily stopped by engine intermittent operation control, while the low-pressure fuel pump is stopped, actuation (opening) of the electromagnetic relief valve is prohibited. At the engine restart after temporary stop, the fuel in the high-pressure delivery pipe having its pressure secured at a certain level is injected to quickly start the engine.

Abstract: A method for operating an engine of a vehicle, the engine having a cylinder with at least a first and second valve, the method comprising during a first mode, operating with the first valve active and the second valve deactivated during a cycle of the cylinder, where during said first mode, the cylinder operates to allow at least air to enter the cylinder during an intake stroke, where the air is mixed with fuel and compressed to attain auto-ignition; and during a second mode, operating with the first and second valves active during a cycle of the cylinder, where during said second mode, cylinder operates to allow at least air to enter the cylinder, where the air is mixed with fuel and ignited via a spark from an ignition plug.

Abstract: A direct injection spark ignition engine comprises a cylinder, a piston, a fuel injector arranged at one side of a center axis of the cylinder for directly injecting fuel into the combustion chamber, and a smoothly continuous lowered recess formed on a top surface of the piston surface. The recess has a first cross section along a first plane including the cylinder center axis and a nozzle end of the injector. The first and second lower contours are smoothly connected with each other through a lowest point of the first cross section. The first lower contour is located at the one side of the cylinder center axis. The second lower contour is at the other side. The first contour has a larger radius than a radius of the second contour. Accordingly, the fuel spray having greater movement energy may impinge the recess at a regulated impinging angle.

Abstract: A method of operating an engine having at least one cylinder during a homogeneous charge compression ignition is provided. The method comprises: directing a first air stream to the cylinder via a first throttle; directing a second, separate, air stream to the cylinder via a second throttle, said first stream at a higher temperature than said second air stream; regulating a total air flow of a mixture of the first and second streams to a desired value by varying both openings of the first throttle and the second throttle in a same direction; and adjusting compression ignition combustion timing by increasing an opening of one throttle and decreasing an opening of the other throttle.

Abstract: A ‘Blackburn Cycle’ or 8 stroke and 4 stroke cycle change piston engine has a separate fuel/air inlet duct and valve in a cylinder where the throttle means admits a small volume, namely less than 10% of the cylinder capacity, needed for a low idling speed. A separate ‘air only’ inlet duct and valve admits alternate ‘air only’ inductions in each cylinder when less than half load is needed. The preferred plug type of throttle can be disc or cone shaped or shaped to substantially fill the volume between the closed throttle and the inlet valve seat. For higher power the throttle moves away from the inlet valve to open the inlet port. Fuel is injected into the small volume between the throttle and the inlet valve where engine heat helps vaporize the fuel without heating a large mass of the inlet air.

Abstract: An intake and exhaust system for a dual mode HCCI engine, which provides superior intake temperature control and homogeneity for engine operation in SI and HCCI modes, as well as during transition between SI and HCCI modes and vice-versa. The system includes adjusted intake cam movement event lengths for intake valve operation at specified modes of operation. The system further includes at least one cam profile switching device operatively connected to intake and exhaust valves in an engine for controlling event length, maximum lift, and valve opening/closing timings for the intake and exhaust valves. The system yet further includes a bifurcated intake system and camless valve actuators for controlling intake valves for facilitating operation in SI or HCCI modes, as well as transition between SI and HCCI modes and vice-versa.

Abstract: An intake manifold with a swirl system for an internal combustion engine having a number of cylinders; the intake manifold has, for each cylinder, an intake conduit connecting the intake manifold to the cylinder and in turn having two parallel channels; the swirl system has, for each intake conduit, a throttle valve housed inside a channel of the intake conduit to vary the air flow section of the channel, and which has a throttle mounted to rotate about an axis of rotation.

Abstract: A method of operating an engine having a hotter and colder airstreams separately controlled to a cylinder is provided. The method controls valve timing during a transition in operating modes to provide improved operation.

Abstract: A divider plate for two or more inlet ports provided in a cylinder head of an internal-combustion engine comprises divider portions that divides inside of the two or more inlet ports along an intake air flow, a side cast-in insert portion provided on at least one side portion located in a direction perpendicular to that of the intake air flow, that is enclosed by molten metal during casting of the cylinder head, an inner cast-in insert portion that is provided between the divider portions, that is enclosed by the molten metal during the casting of the cylinder head, and an inner accelerator formed in the inner cast-in insert portion, accelerates coagulation of the molten metal, wherein the inner accelerator has at least one of a plurality of holes, a concave portion, a convex portion, and a concave-convex portion, or a combination of a hole and a concave portion, a convex portion or a concave-convex portion.

Abstract: A fuel injector for an internal combustion engine which has a spray hole designed geometrically to produce a spray of fuel so that substantially 70% or more of an amount of the spray hits a preselected area of a head of an intake valve of the engine when the intake valve is closed. The preselected area is one of a first and a second area of the intake valve head which are defined by a reference boundary line extending through a base end of a stem of the intake valve. The preselected area is the first area closer to an intake manifold, while the second area is closer to an exhaust valve. This avoids rich misfire and reduces HC emissions from the engine regardless of the intake valve is in a closed state or in an open state.

Abstract: An intake port structure includes a collector passageway disposed in an upstream section and the first and second branching passageways disposed in a downstream section that branch from the collector passageway. The intake port structure further includes an intake air flow impact section formed on a crotch portion between first and second branching passageways against which a portion of an intake air flow from the collector passageway collides such that the portion of the intake air flow is dispersed laterally toward both sides of the intake air flow impact section. The intake air flow impact section is recessed to stem portions of intake valves, and includes first and second impact surfaces. The second impact surface is formed along the stem portions of the intake valves. A fuel spray from a fuel injector is atomized when mixed with the dispersed intake air flow in the first and second branching passageways.

Abstract: A method is disclosed for expanding the mid load range of a four-stroke gasoline direct-injection controlled auto-ignition combustion engine. The engine includes at least one cylinder containing a piston reciprocably connected with a crank and defining a variable volume combustion chamber including an intake valve controlling communication with an air intake and an exhaust valve controlling communication with an exhaust outlet. A system is employed for variably actuating the intake and exhaust valves. The valve actuating system is employable to operate the intake and exhaust valves with an exhaust re-compression or an exhaust re-breathing valve strategy. A reservoir chamber in communication with the combustion chamber is provided for temporary holding of residual burned gas. Residual burned gas in the combustion chamber and the exhaust outlet enters into the reservoir chamber and then loses thermal energy while in the reservoir chamber before being drawn back into the combustion chamber.

Abstract: A method is disclosed for controlling the air-fuel ratio in a four-stroke gasoline direct-injection controlled auto-ignition combustion. The engine is operated with two sequential pairs of expansion and contraction strokes during two revolutions of the engine crank, the two revolutions defining a combustion cycle. A system is employed for variably actuating the intake and exhaust valves and adjusting the flow of air and burned gases entering the combustion chamber. Adjusting the flow affects the resulting air-fuel ratio in the combustion chamber. The valve actuating system is employable to operate the intake and exhaust valves with an exhaust re-compression or an exhaust re-breathing valve strategy. Either valve strategy affects the air-fuel ratio in the cylinder and causes a proportion of burned gases from previous combustion cycles to be retained in the cylinder to provide the necessary conditions for auto-ignition of the air-fuel mixture.

Abstract: A system and method to control engine valve timing of an internal combustion engine. Electromechanical valves are controlled in a manner to increase fuel economy. Further, the method can adjust valve operation to regulate valve temperature.

Abstract: In a center injection type of direct engine, since it has an ignition plug and an injector arranged in proximity, there occurs the problem that a sprayed liquid fuel directly strikes the ignition plug and causes the plug to misfire. A notch is to be provided at a portion of the injector end so as to form a coarse-grained portion and a dense portion in sprays of fuel, and the injector is disposed so that the coarse-grained portion is directed towards the ignition plug. It is possible to avoid the misfiring of the ignition plug and thus prolong the life of the plug, by preventing a liquid fuel from directly striking the plug.

Abstract: When an inner wall of a cylinder head is viewed along an axis of a cylinder, a line that passes through a center of a fuel injection port and a center of a valve opening adjacent to the injection port is defined as a first line, and a line that is perpendicular to the first line is defined as a second line. A notch is formed in a part of the inner wall that defines the injection port. Specifically, when the inner wall is divided into sections by the second line, the notch is located in the section in which the adjacent opening exists. The notch is also displaced from the first line. Therefore, a sufficient thickness of the section corresponding to the valve seats of intake and exhaust valves are easily ensured.

Abstract: An internal combustion engine includes an intake port leading to an engine cylinder. The intake port is divided into first and second passage section by a partition extending in the intake port in a longitudinal direction of the intake port. A gas motion control valve is arranged to open and close an upstream end of the second passage section. A connection passage connects an upstream end portion of the second passage section to the first passage section. A fuel injector is directed to inject fuel toward a valve opening of the intake valve through a space on the downstream side of the downstream end of the partition.

Abstract: An internal combustion engine includes an intake port leading to an engine cylinder. The intake port is divided into first and second passage section by a partition extending in the intake port in a longitudinal direction of the intake port. A gas motion control valve is arranged to open and close an upstream end of the second passage section. A connection passage connects an upstream end portion of the second passage section to the first passage section. A bulge is formed in a first part of a circumferential region surrounding the downstream port end so as to prevent air from being drawn from the cylinder into the second passage section.

Abstract: An internal combustion engine includes at least two intake valves per cylinder, and at least two intake ports leading to the intake valves, a first intake port preferably being configured as unthrottled tangential passage and the flow through a second intake port being controlled by means of a first throttle element (11) actuated in dependence of at least one engine parameter, and at least one fuel injector per cylinder injecting fuel into at least two intake ports, wherein in the closed position of the first throttle element at least one leakage aperture will permit a defined minimum flow through the second intake port.

Abstract: A novel combustion chamber configuration locates the stems of all four of its valves in a parallel with the axis of the engine cylinder closed by the chamber. In this variation which is especially well suited for a barrel-stratified mode of engine operation, the spark plug can readily be offset a moderate distance from the axis of the cylinder into the fueled side of the combustion chamber because the pair of intake valves is separated from the pair of exhaust valves by an extra amount. The associated overlapping of the intake valve faces outside of a projection of the cylinder bore is utilized to form two symmetric flow masks which in turn function as the primary means for generating strong barrel swirl during the intake stroke.

Abstract: The invention relates to an internal combustion engine with spark ignition and direct fuel injection. The inventive engine comprises: a cylinder; a cylinder head; a piston which is mounted to slide in the cylinder; a combustion chamber which is defined in the cylinder between the cylinder head and the piston; a fuel injector which opens into the combustion chamber; a spark plug; inlet and exhaust valves; and a fuel injection pump which supplies the injector with a flow of pressurized fuel. According to the invention, the pressure of the fuel flow supplied to the injector exceeds 300 bar and, preferably, reaches or exceeds 500 bar.

Abstract: A state of combustion in a combustion chamber is controlled by stratifying an intake gas charge within the combustion chamber, so as to reduce amounts of harmful substances left in exhaust gas. A direct-injection type internal combustion engine in which a fuel is injected into the combustion chamber and which is arranged to stratify the intake gas charge within the combustion chamber (1) such that intake gases of different compositions exist in a central portion (13) of the combustion chamber including a position of the fuel injection, and in a peripheral portion of the combustion chamber, upon initiation of combustion of the fuel at a point of time near a terminal period of a compression stroke. The intake gases of different compositions may be intake gases having different concentrations of a specific component such as recirculated exhaust gas and the fuel.

Abstract: In a center injection type of direct engine, since it has an ignition plug and an injector arranged in proximity, there occurs the problem that a sprayed liquid fuel directly strikes the ignition plug and causes the plug to misfire. A notch is to be provided at a portion of the injector end so as to form a coarse-grained portion and a dense portion in sprays of fuel, and the injector is disposed so that the coarse-grained portion is directed towards the ignition plug. It is possible to avoid the misfiring of the ignition plug and thus prolong the life of the plug, by preventing a liquid fuel from directly striking the plug.

Abstract: An engine is provided which includes various precise configuration parameters, including dimensions, shape and/or relative positioning of the combustion chamber features, resulting in a combustion process minimizing NOx emissions and particulates. The combustion chamber includes a spray angle relative to an inner bowl floor angle that maximizes the amount of fuel in contact with the inner bowl, in combination with one or more of the following: a vertical distance from the tip of the piston bowl to the injection orifices; a number of injection orifices; a swirl ratio; a vertical distance from the injection orifices to an inner face of the cylinder head; a distance from the piston top surface to the cylinder head; a radius of curvature of an outer bowl section; a radius of curvature at an edge of the piston bowl; a ratio of the piston bowl diameter to the cylinder diameter; and the cylinder diameter.

Abstract: When an inner wall of a cylinder head is viewed along an axis of a cylinder, a line that passes through a center of a fuel injection port and a center of a valve opening adjacent to the injection port is defined as a first line, and a line that is perpendicular to the first line is defined as a second line. A notch is formed in a part of the inner wall that defines the injection port. Specifically, when the inner wall is divided into sections by the second line, the notch is located in the section in which the adjacent opening exists. The notch is also displaced from the first line. Therefore, a sufficient thickness of the section corresponding to the valve seats of intake and exhaust valves are easily ensured.

Abstract: There is provided a cylinder injection type internal combustion engine capable of performing stratified charge operation at the time of a vehicle speed of 120 km/h and/or an engine rotational speed of 3200 rpm to enhance the fuel efficiency and/or to observe the emission regulations. In the internal combustion engine, a stratum of air and/or air flow is formed between a fuel spray injected from an injection valve and the top face of a piston and/or the wall surface of a combustion chamber, and a face shape contrived to guide the air flow is formed on the top face of the piston. Also, the stratified charge operation can be performed even at the time of cold start or cranking.

Abstract: A combustion chamber arrangement for a direct fuel injected internal combustion engine wherein the combustion chamber is formed in part by a recess in the piston head. Fuel is injected into the combustion chamber so as to be introduced on one side of the recess with a spark plug being positioned so that its gap lies diametrically opposite the fuel injector. An arrangement is provided for introducing a swirl to the flow of fuel and the combustion chamber recess is canted so that its lower surface is deeper where the fuel first enters then on the other side so as to improve flame propagation and complete combustion while maintaining a high compression ratio.

Abstract: A direct fuel injection engine includes a fuel injector so positioned and oriented as to produce a fuel spray whose upper segment reaches the vicinity of a spark plug by a penetrating force of the fuel spray in a low engine speed light load operating region to achieve stratified charge combustion without the aid of tumble. A tumble control valve is operated to strengthen the tumble in a combustion chamber to achieve stratified charge combustion with the aid of tumble in an engine operating region higher in engine speed and/or engine load.