Abstract: A number of embodiments of cylinder head and intake port arrangements for multiple valve, internal combustion engines particularly those having three or more intake valves. The configuration promotes turbulence in the combustion chamber by inducing a tumble action even from the center intake valve seat. In addition, each of the valve seats and its associated flow passages are configured so as to provide optimum tuning for different engine speeds so as to improve the torque of the engine throughout its entire speed and load ranges and to provide good breathing efficiency throughout all engine speeds. Various porting and throttle and fuel injection systems are shown wherein siamesed intake passages are formed for at least two of the valve seats.

Abstract: The present invention seeks to provide, inter alia, further methods to generate swirl and reduce cross flow in spark ignition internal combustion engines having two inlet and two exhaust valves per cylinder head, without the use of additional moving parts.

Abstract: The invention concerns a direct injection internal combustion engine comprising a camshaft and at least two cylinders (1), having in each cylinder a mobile piston (2) associated with at least to intake valves (4, 5), each located in an induction pipes (8, 9), and at least an exhaust valve (6, 7). The displacement of said valves is independent of the rotation of the camshaft and is controlled by a computer (15). The induction pipes (8, 9) are designed to produce an air velocity field inside the cylinder (1) parallel to said cylinder axis. The computer (15) controls, cylinder by cylinder, the opening and closing times of said at least two intake valves (4, 5) to adapt the shape of the air velocity field inside the cylinder (1) to the engine power.

Abstract: A method for controlling intake valves in an internal combustion with intake valves operated by more than one type of actuation device includes steps to accomplish smooth transitions among intake valve operating modes.

Abstract: The invention relates to a control process for charge flow management devices as arranged in the intake area of the inlet ports of direct-injection internal combustion engines and port-injection type internal combustion engines having intake ports into which no fuel is injected. The process is characterized by the fact that the charge flow management devices are not closed when the engine operates on overrun. This reduces fouling on the intake valves produced by fuel and lubricant residue.

Abstract: For a spark ignited internal combustion engine having at least two inlet valves per cylinder each with a separate inlet passage and with a fuel injection device which injects fuel directly into the cylinder. An air charger for generating an air charge into one of the inlet passages and a connecting duct extending between the two inlet passages with a selectively opened and closed regulating device therein to apportion the flow of charge air through the separate inlet passages.

Abstract: A poly valve system for an internal combustion engine having at least one cylinder having a bore and a cylinder center line, a piston capable of reciprocal travel within the bore, a cylinder head adjacent the bore having a hemispherical cylinder roof, intake and exhaust manifolds, and a combustion chamber defined between the cylinder head and the piston, comprising a plurality of independently operated valves. Valve seats comprise openings in the cylinder head between one of the manifolds and the combustion chamber. Poppet valves are situated in the valve seats to selectively allow communication between one of the manifolds and the combustion chamber. The valves are independently operable by a control signal, are non-parallel, and are oriented toward the cylinder center line.

Abstract: The invention relates to a spark ignited internal combustion engine with at least one cylinder that accommodates a reciprocating piston, with a cylinder head that receives at least one ignition device per cylinder and in which are formed one exhaust and two intake manifolds, said exhaust manifold communicating with a combustion chamber by way of one exhaust port and said intake manifolds communicating therewith by way of intake ports, said exhaust port being controlled via an exhaust valve and said intake ports via intake valves, said exhaust port on the one hand and said intake ports on the other hand being arranged to different sides of an elevated plane of the engine that passes through the axis of the cylinder and through the axis of the crankshaft, said intake manifolds being at least in sections arranged substantially in the direction of the cylinder's axis and being formed in such a manner that a reverse tumble flow is initiated in the combustion chamber, said flow being oriented from the intake ports

Abstract: A control device in an internal combustion engine interlocking with a device to generate swirls in a combustion chamber of the internal combustion engine by providing bypass passages which allow air to bypass a throttle valve for regulating intake air flow rate of the internal combustion engine to control an output power of the internal combustion engine and allow the air to flow in from the atmosphere side to communicate with air intake ports for respective cylinders on the downstream side of the throttle valve.

Abstract: A poly valve system for an internal combustion engine having at least one cylinder having a bore, a piston capable of reciprocal travel within the bore, a cylinder head adjacent the bore, and a combustion chamber defined between the cylinder head and the piston, comprising a plurality of independently operated valves. Intake and exhaust manifolds are located adjacent to the cylinder head. Valve seats comprise openings in the cylinder head between one of the manifolds and the combustion chamber. Poppet valves are situated in the valve seats to selectively allow communication between one of the manifolds and the combustion chamber. The valves are electrically, pneumatically, or hydraulically operated so that each valve, including one of several intake valves per cylinder, may be operated independently of each other.

Abstract: A poly valve system for an internal combustion engine having at least one cylinder having a bore, a piston capable of reciprocal travel within the bore, a cylinder head adjacent the bore, and a combustion chamber defined between the cylinder head and the piston, comprising a plurality of independently operated valves. Intake and exhaust manifolds are located adjacent to the cylinder head. Valve seats comprise openings in the cylinder head between one of the manifolds and the combustion chamber. Poppet valves are situated in the valve seats to selectively allow communication between one of the manifolds and the combustion chamber. The valves are electrically, pneumatically, or hydraulically operated so that each valve, including one of several intake valves per cylinder, may be operated independently of each other.

Abstract: The invention relates to an intake port configuration (1) for an internal combustion engine, where the swirl (D) of at least one intake flow entering the combustion chamber via an intake port controlled by an intake valve (5) can be varied, two or more flow paths being associated with at least one intake port, which paths join in the valve region (4), and the flow rate (Q) in at least one of the two flow paths being variable by means of a control element (9), and the two flow paths being constituted by two completely separate intake passages, i.e., a primary passage (2) and a secondary passage (3), said primary passage (2) having a helical form. In order to obtain a high flow rate (Q) at a high swirl level in addition to a wide range over which the swirl D may be varied, it is proposed that the intake valve axis (5a) should intersect or be tangent to the secondary passage (3) at least at one point.

Abstract: A system and a method for controlling engine torque in an internal combustion with a randomly operable intake valve and a selectable intake valve is disclosed in which torque is controlled via a throttle valve when the randomly operable intake valve is deactivated and via intake valve closing time of the randomly operable intake valve when the selectable intake valve is deactivated.

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 method for controlling intake valves in an internal combustion with intake valves operated by more than one type of actuation device includes steps to accomplish smooth transitions among intake valve operating modes.

Abstract: The present invention relates to a variable tumble flow-generating device, which comprises: a bulkhead for dividing an intake port into a first passage and a second passage; an opening degree control valve for selectively changing an opening degree of the first and second passages; and driving means for operating the opening angle control valve. This variable tumble flow-generating device can generate tumble flow by making air flow through different passages while minizing a flow resistance of air supplied into the combustion chamber, and which has a simple structure so that a limitation in its installation space in relation with other parts can be avoid. Also, the variable tumble flow-generating device is manufactured by adding only a structure where the bulkhead is previously assembled with the intake port core of the prior art. For this reason, this is a simple structure and thus is manufactured at inexpensive costs.

Abstract: A representative version of a combustion system for spark-ignition engines adapts the classic four-valve pentroof combustion chamber to stratified charge operation by (1) restricting fuel delivery to one of the two intake passages serving each combustion chamber and (2) initiating combustion at an offset spark plug location with a sufficient lead in spark timing for fueled mixture to be pushed into the vicinity of a central spark plug before it is fired according to a second spark timing schedule with less advance. In a wide range of higher BMEP which makes a transition to homogeneous charge operation, central fuel metering components become active and the engine throttle stays at least effectively wide open.

Abstract: Two intake valves are independently operated by electro-mechanical actuators and activated by the engine electronic controller. One tumble-type intake valve and one conventional intake valve are provided in each cylinder. The valve members are individually opened and closed to achieve a desired air flow pattern in the combustion chamber to optimize combustion which increases fuel economy and reduces undesirable emissions. The opening and closing of the valve members depends on the engine speed, engine load, and other factors.

Abstract: Swirl motion of gases in a combustion chamber of an engine is affected by changing the timing of opening and closing one of two intake and/or exhaust valves. By retarding the opening of one intake valve relative to a second intake valve, swirl motion can be enhanced for the intake gases in the engine cylinder. Similarly, by retarding the opening of one of two exhaust valves, swirl motion can be induced for the residual gases. The system may include electric or hydraulic actuators or mechanically controlled valves. A variable valve lift system can also be used to control swirl motion in a combustion chamber.

Abstract: A charge motion control valve 10 for use in combination with an internal combustion engine having “Siamese” type fuel intake ports 18, 20. Valve 10 has an asymmetrical shape which provides for improved engine stability during cold start operating conditions by causing condensed fuel to be removed from intake valves and properly mixed and combusted within a cylinder of the engine.

Abstract: A valve train for a small size diesel engine includes a pair of camshafts rotatively supported by and passing over a top of a cylinder head, one pair of intake and exhaust cams on each camshaft for each cylinder, two intake ports and two exhaust ports formed on the cylinder head over and around a bore center of each cylinder for communicating with the cylinder bore, two intake valves and two exhaust valves installed into the corresponding ports for selectively opening and closing the ports, rocker arms of which one end of each is connected to upper ends of the corresponding valves, and lash adjusters connected to other ends of the corresponding rocker arms for adjusting lash between the rocker arms and the cams, wherein the intake and exhaust ports are arranged in an alternative zigzag fashion.

Abstract: A method for controlling intake valves in an internal combustion with intake valves operated by more than one type of actuation device includes steps to accomplish smooth transitions among intake valve operating modes.

Abstract: A common intake port 10 is branched into a pair of branch intake ports 12, 24, which are separated through a partition wall 11, at the downstream end thereof. A pair of intake valves 16, 17 adapted to independently open and close the pair of branch intake ports 12, 14, respectively, are provided. In a four-stroke cycle internal combustion engine 1 adapted so that one 16 of the pair of intake valves 16, 17 opens and closes in a low intake air operating range, while the other intake valve 17 is in a resting condition, and that both the pair of intake valves 16, 17 open and close in a high intake air operating range, a cutout 57 is formed in a laterally central portion of the partition wall 11 in such a way as to extend from the edge of the upstream end of the partition wall 11 toward the downstream end thereof and to separate the pair of branch intake ports 12, 14 from each other.

Abstract: In a direct fuel injection-type spark ignition internal combustion engine including a spark plug and a fuel injector for injecting fuel directly into the cylinder, the engine can carry out stratified charge combustion by the fuel injection in the compression stroke and uniform charge combustion by the fuel injection in the intake stroke. The engine includes a mechanism which can make a tumbling stream formed in the cylinder in the intake stroke in the stratified charge combustion weaker than that in the uniform charge combustion.

Abstract: A four-stroke reciprocating internal combustion engine that uses stratified exhaust gas recirculation to improve combustion is disclosed. The engine includes at least one combustion chamber defined by a cylinder, a reciprocating piston contained within the cylinder, and a cylinder head. Each combustion chamber is in fluid communication with at least one intake port and at least one exhaust port. At least one intake port includes an associated intake valve, an intake flow motion generating device and an associated intake flow direction control device for creating an intake fluid flow near the center of the cylinder. At least one exhaust port includes an exhaust valve that opens during the intake stroke at part load, an exhaust flow motion generating device and an associated exhaust flow direction control device for creating an exhaust fluid flow near the outer periphery of the combustion chamber during the intake stroke at part load.

Abstract: An internal combustion engine comprises intake and exhaust valves. An electromagnetic actuator is provided for actuating each intake valve so that the intake valve makes its opening and closing action. A control unit is provided for controlling the electromagnetic actuator in accordance with engine operating conditions. The control unit is arranged to control the electromagnetic actuator in a manner to cause the intake valve to make first and second opening and closing actions in an intake stroke in synchronism with intake air pulsation. The first opening and closing action is before in time the second opening and closing action.

Abstract: A control device in an internal combustion engine, interlocking with a device to generate swirls in a combustion chamber of the internal combustion engine by providing bypass passages which allow air to bypass a throttle valve for regulating Intake air flow rate of the internal combustion engine to control an output power of the internal combustion engine and allow the air to flow in from the side of atmosphere to communicate with air intake ports for respective cylinders on the downstream side of the throttle valve The device comprises sensors to detect a vehicle speed, a gear position, an opening of an accelerator, an intake air flow rate and the like and a processor to determine an operating state of the internal combustion engine such as a rotating speed, a torque and the like based on the signals from the sensors, calculating an operating condition of the internal combustion engine according to the strength of swirl to be generated based on the operating state, outputting the calculated values as control

Abstract: A linkage device of a V-type internal combustion engine rotates a pair of drive shafts for changing openings of swirl control valves. The linkage device receives reciprocating motion from an actuator through a rod. A center lever connected to the rod changes the reciprocating motion to swing motion and transfers the swing motion to right and left links. The right and left links are connected to the drive shaft through right and left levers, respectively. The right and left links and the right and left levers change the swing motion to rotational motion and apply the rotational motion to the drive shafts.

Abstract: A cylinder injection type lean-burn internal combustion engine is capable of executing the purging of a vapor fuel without disturbing a state of an air-fuel mixture in a combustion chamber. The vapor fuel produced in a fuel tank is guided to a purge port provided at an intake passageway of the lean-burn internal combustion engine, and subsequently supplied along an intake air swirl flow into the combustion chamber. The vapor fuel is thereby partially concentrated in any one of a combustible air-fuel mixture layer and an air layer in the combustion chamber.

Abstract: An air/fuel mixture induction system for an internal combustion engine having a pair of intake valves, an intake air/fuel mixture flow passage communicating with each valve, a primary mask surrounding a portion of the perimeter of one of the intake valves, the air/fuel mixture being directed from the intake valve over the remaining peripheral portion thereof, thereby establishing a swirl motion in the combustion chamber, a secondary bridge mask partially surrounding the other of the pair of intake valves, the secondary bridge mask having an air/fuel mixture flow controlling surface that directs the swirl motion of the air/fuel mixture in the direction of the axis of the cylinder whereby swirl motion progresses in the direction of the axis of the cylinder throughout the combustion chamber.

Abstract: A three-valve cylinder head system for a direct-injected spark-ignited (DISI) internal combustion engine. Two inlet ports are positioned in opposite quadrants of the cylinder head, with the fuel injector directing fuel spray into a third quadrant and the exhaust port being positioned in the fourth quadrant. A helicoid intake port and an axially directed intake port generate a swirl-type air flow in the piston cylinder without the aid of flow activation devices. The spark plug is positioned centrally adjacent the longitudinal axis of the cylinder bore. The piston has a bowl in its upper surface with an enlarged downstream area and a harbor area adjacent and past the spark plug which allow the swirl-type air flow to mix with the fuel spray and provide an appropriate fuel air mixture at the spark plug.

Abstract: A multiple intake valve engine has a first intake port (1) and second intake port (2). The first intake port (1) has an outlet (7), and the second intake port (2) has an outlet (8). The first intake port (1) is provided upstream of the second intake port (2) with respect to a swirl (S) generated in a respective cylinder (3) of the engine. A near-outlet part (16) of the first intake port (1) is directed toward an area (A) between the second intake port outlet (8) and a cylinder inner wall (12a) located on the upstream side of this outlet (8) in the direction of the axis (Cp) of the second intake port (2). A powerful swirl (S) is generated under all circumstances, and the swirl (S) is strengthened without sacrificing an amount of intake air.

Abstract: An entire peripheral surface of a port bent portion (5) of a direct intake port (2) has a peripheral side surface portion (11) close to a cylinder axis (10). The peripheral side surface portion (11) provides a projection (12) for deviating intake air current (A) from the peripheral side surface portion (11) toward an opposite peripheral side surface portion (13). Further, the bent portion (5) has a peripheral side surface portion (14) close to an upper end surface (9) of a cylinder chamber (8), which provides a projection (15) for deviating the intake air current (A). This projection (15) turns a direction of the intake air current (A) from a peripheral side surface portion (14) close to the upper end surface (9) of the cylinder chamber (8) toward an opposite peripheral side surface portion (16).

Abstract: A spark ignition internal combustion engine is described having a fuel supply system for separating the fuel into two or more continuous streams of fuel fractions having different octane ratings. The engine has an intake system that creates within each combustion chamber a stratified charge comprising at least two regions 113, 123 each containing a higher concentration of respective one of the fuel fractions. Each combustion chamber also has two spark plugs 114, 124 each located in a respective one of the stratified charge regions. The engine ignition system separately controls the spark timings of the spark plugs 114, 124 to vary the pattern of flame propagation through the stratified charge in the combustion chambers in dependence upon the engine operating conditions.

Abstract: An internal combustion engine with valve rest mechanisms. Exhaust secondary air is introduced at an exhaust port in a stable manner regardless of the resting, opening and closing operations of exhaust valves. Certain exhaust valves in the internal combustion engine are equipped with valve rest mechanisms. Exhaust valves that are not equipped with valve rest mechanisms located on neighboring cylinders are located on neighboring sides of their respective cylinders.

Abstract: An automotive valve rocker arm comprises a valve engagement portion and a cam engagement portion which are mounted for independent rocking movement about a rocker shaft. One of the cam engagement portion and valve engagement portion affords a first bush, which accommodates and is rotatable about the rocker shaft, and the other of which affords a second bush, which accommodates the first bush and is rotatable about the first bush and thus about the rocker shaft also. Selectively actuable locking means are accommodated within the space defined by the outer surface of the second bush and are movable between a first position in which relative movement of the valve engagement portion and the cam engagement portion is permitted and a second position in which they are locked together and such relative movement is prevented.

Abstract: In an intake passage arrangement in an internal combustion engine at least two intake ports located in a cylinder head depart from a common intake flow path. In the area where the flow path branches into the separate intake ports a swirl control device configured as a control flap is positioned, which is rotatable about a rotation axis situated at one end of the control flap. In one position the control flap opens both intake ports, whereas it blocks one intake port in another position. To ensure control of the swirl motion of the intake flow entering the combustion chamber and to permit a most simple and compact design an intermediary part carrying the control flap is essentially configured as a thin, flat frame, and preferably as a die-cast part made of aluminum.

Abstract: A cylinder head for a four-valve per cylinder internal combustion engine comprises a bowl-shaped combustion chamber recess on a lower surface which cooperates with a piston in a cylinder to form a combustion chamber. The combustion chamber recess has first and second exhaust openings, and first and second intake openings. First and second exhaust ports extend from the first and second exhaust openings to an exhaust outlet through an exhaust side wall of the cylinder head. First and second intake ports, divided by a septum, extend from the first and second intake openings, along a curved flow path, to an intake passage. The intake passage delivers intake charge from an intake inlet in an intake side wall of the cylinder head to the first and second intake ports. The first and second intake ports have first and second intake valves to regulate flow of intake charge through the intake valve openings.

Abstract: An intake system for an internal combustion engine includes an intake manifold having a plenum connected to ambient air by a main throttle and branches leading from the plenum to an intake port of each cylinder. A storage pipe is connected and parallel with each of the intake manifold branches. Gases from an auxiliary supply are drawn by the intake manifold vacuum into the storage pipe and thence into the engine cylinders.

Abstract: The invention relates to a multicylinder four-stroke internal combustion engine having a cylinder head (1) with an intake and an outlet port arrangement for two admission valves (15, 16, 17, 18) and two exhaust valves (26, 27) per cylinder. The admission valves (15, 16, 17, 18) are fitted on opposite-lying longitudinal sides of the engine and the exhaust valves (26, 27) on respective opposite side walls in relation to the crankshaft axis. One swirl duct (11, 12) and one filling duct (13, 14) leading to the admission valves (15, 16, 17, 18) are provided per cylinder (7, 8).

Abstract: An internal combustion engine includes a piston reciprocably housed within a cylinder and hybrid intake valves, with one intake valve being driven by a camshaft and at least one intake valve being selectively powered by a power source other than the camshaft, such as a solenoid.

Abstract: A number of embodiments of induction systems for multiple valve internal combustion engines wherein the performance of the engine is improved throughout the engine speed and load ranges by providing variable effective areas for the induction passages. The embodiments disclosed all relate to three intake valve engines and show a number of different variations in intake passages. In all embodiments an EGR system is employed for improving exhaust emission control.

Abstract: An engine cylinder system (1) is disclosed. The system (1) is comprised of at least one cylinder (2) capped with a cylinder head (4), combustion chamber (7), and piston (25). The cylinder head (4) is provided with inlet passages (11, 12) and exhaust passages (29, 30) in fluid communication with the combustion chamber (7) via openings (22, 23, 31, 32). The openings (22, 23) are provided on the head (4) diametrically opposite such that inlet gases (35, 36) can generate powerful turbulence within the chamber (7).

Abstract: An internal combustion engine cylinder head includes a pent roof (15) closing off a top of an engine cylinder (14) and first and second inclined surfaces (15a, 15b) intersecting an apex region (15c) of the pent roof. First and second air intake ports (20, 22) are formed in the pent roof surfaces and about respective first and second spiral axes (S1, S2) having respective radii (R1, R2, etc.) that change in magnitude and elevation as each air intake port approaches respective port entrances (20a, 22a) to the cylinder in a manner to provide air flows with in-cylinder air swirl in the same direction about the longitudinal axis of the cylinder.

Abstract: A multi-cylinder internal combustion engine is provided with an intake port injection system capable of effectively delivering port injected quantities of fuel to each cylinder while minimizing the number and size of the fuel injectors. The intake port injection system of the present invention includes a siamese or shared port arrangement having a plurality of common intake inlets, each delivering air from an intake manifold to one intake port of one cylinder and an intake port of a different cylinder. Two single intake inlets are also provided for delivering intake air solely to a single respective cylinder. Importantly, in a multi-cylinder engine having a total number of cylinders equal to N, the number of intake inlets, both common and single, equals N+1. Importantly, the total number of injectors also equals N+1. Although each intake inlet is served by only one injector, two injectors operate simultaneously to deliver fuel to a single cylinder via respective intake inlets.

Abstract: A cylinder head for internal combustion engines, particularly diesel engines with direct fuel injection, which has two inlet valves per cylinder each including spin-inducing means for producing spin flow about the longitudinal axis of the associated cylinder. Having regard to the direction of spin, the leading inlet valve is provided with an eccentric, crescent-shaped chamfer facing in the general direction of spin flow, and the trailing inlet valve includes flow blocking means for preventing combustion air from exiting the trailing inlet valve in a direction opposite to the direction of spin flow.

Abstract: An improved intake equipment, in which the formation of a liquid fuel film due to deflection of the fuel can be avoided, has a plurality of independent air intake pipes connected to a combustion chamber, for introducing air thereto, collectors connected to the independent air intake pipes, for distributing the introduced air into them, and a throttle valve connected to the collectors, for controlling the amount of air flow. A fuel supplying mechanism is provided on a wall of the independent intake pipes, for supplying fuel to the air and mixing the air and fuel, and a deflection mechanism is provided for deflecting the air flow of the independent intake pipes so as to avoid undersirable deflective of the fuel.

Abstract: A control valve arrangement for a three-valve-per-cylinder internal combustion engine. The control valve arrangement controls not only the effective length of the intake passage serving each combustion chamber, but also controls the flow through the intake passage so as to generate turbulence under low-speed and low-load conditions. The control valve further includes a pair of valves which change not only the effective flow area, but also the effective flow direction. In this way varying degrees and types of turbulence can be generated during different engine running conditions. A number of different types of valve arrangements are disclosed.

Abstract: A cylinder head for an internal combustion engine of the reciprocating piston type includes a helical inlet port with a flat wall portion in a section of the port upstream of a bowl-shaped recess about a valve stem guide. The flat walled section meets a generally cylindrical portion of the recess adjacent a cusp-shaped swirl edge. The orientation of the flat portion with respect to a reference feature, such as the axis of the valve stem guide, may then be used as a measure of the accuracy of casting of the inlet port, and may also be altered if so desired to vary the swirl characteristics of the inlet port.

Abstract: An air intake arrangement for an internal combustion engine comprising: a main air intake conduit leading to a gas intake valve (241) for respective engine cylinders (206) and including a main air intake passage (202), a main collector chamber (204) and independent branching air intake passages (205) for the respective engine cylinders (206) connected in series; a throttle valve (203) disposed in the main intake air passage (202) for controlling the flow rate of air passing therethrough; an auxiliary air intake passage (210) bypassing the main air intake conduit, wherein an inlet port of the auxiliary air intake passage (210) opens into the main air intake passage (202) at the upstream of the throttle valve (203), and an outlet port (213) of the auxiliary air intake passage (210) opens into the respective independent branching air intake passage (205) near the gas intake valve (241) for the respective engine cylinders (206) in such a manner that gas blown-out from the auxiliary air intake passage (210) induc