Abstract: A valve train is disclosed for an internal combustion engine having a block, a camshaft in the block, and at least two push rods actuated by the camshaft. The valve train comprises first and second rockers, and three valves. The first rocker is actuated by one of the push rods, and the second rocker is actuated by another of the push rods. A first valve is associated with a cylinder of the engine and actuated by the first rocker. A second valve is associated with the cylinder and actuated by the first rocker, and a third valve is associated with the cylinder and actuated by the second rocker.

Abstract: A fuel delivery system includes a drop ejector for discretely ejecting drops of combustible liquid in a digital manner. A controller is configured to cause the drop ejector to provide a first air/fuel mixture to a combustion chamber for a first portion of a fuel intake period and to provide a second air/fuel mixture to said combustion chamber for a second portion of the same fuel intake period.

Abstract: An internal-combustion engine with two inlet valves for each cylinder is provided with an electronically controlled system for actuating said valves. The electronic control unit is programmed so as to control in a differentiated way the two inlet valves according to a first law of opening and closing and a second law of opening and closing, which are different from one another. The electronic control means are moreover designed for reversing with respect to one another the laws of opening and closing of the two inlet valves at each operating cycle of the engine or else with a periodicity equal to more than one operating cycle of the engine, so that each of the two inlet valves alternately follows the first law and the second law of opening and closing.

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 p

Abstract: A duct system suitable for use as an intake manifold for an internal combustion engine, including flap valves (13) for selective opening and closing of the ducts. The positions of the valves are continuously adjustable in order to produce a swirl in the flow of combustion air. To achieve this, a high degree of angular precision is required in the positioning of the valves. Intake manifold manufacturing tolerances need to be compensated during assembly of the valves. A valve adjusting mechanism is provided in mechanical couplings (23) of the valve linkage between the position adjusting motor (19) and the flap valves (13).

Abstract: An outboard motor includes an internal combustion engine provided with a pair of intake valves. The opening and closing operation of one of the intake valves can be paused. The internal combustion engine comprises a vertical crankshaft, a cylinder head provided with an intake port having a pair of intake openings for one combustion chamber, and a fuel injection valve for injecting the fuel into the intake port. The intake port has an upper branch section and a lower branch section extended under the upper branch section. A valve train includes a valve-operation mode changing mechanism. The valve-operation mode changing mechanism pauses the opening and closing operation of the first intake valve and operates the second intake valve for opening and closing the lower intake opening of the lower branch section while the internal combustion engine is operating at engine speeds in a low-speed range.

Abstract: A side valve internal combustion engine provided with at least one combustion cylinder having a piston. At least two intake valves and at least one exhaust valve are provided for each of the combustion cylinders. In order to maintain a compact engine and provide a nozzle-type combustion chamber, the intake valves and exhaust valve are locate to one side of the combustion chamber in the engine block. The exhaust valve is further located at a greater distance from the combustion cylinder than the intake valves in order to decrease heat distribution on the cylinder walls. The nozzle-type chamber provides for efficient flow of gases within the engine.

Abstract: The invention relates to an internal combustion engine run on Otto fuel which may be compression ignition operated in a first operational range (HCCI) and spark ignition operated in a second operational range (SI), with means for adjusting valve timing of at least one intake valve (7) and of at least one exhaust valve (8), with at least one ignition equipment (18) and at least one direct injection equipment (17) in each cylinder (1). To permit in the easiest possible way compression ignition and spark ignition operation on Otto fuel, there is provided at least one intake camshaft (9) for actuating the intake valves (7) and at least one exhaust camshaft (10) for actuating the exhaust valves (8), that at least one intake valve (7) in each cylinder (1) is movable between a first and a second lift position by a device for changing the valve lift (11), and that at least one exhaust valve (8) is actuatable by a residual gas recirculation system (13) during the intake lift.

Abstract: The invention comprises at least two independent intake ports 14a, 14b connected to a combustion chamber 15, two intake valves 12a, 12b, and two exhaust valves 13a, 13b. Upper and lower channels 22a, 22b which are defined by a partition wall, and an intake control valve 25 for opening and closing the lower side channel 22b are provided in the interior of the first intake port 14a. An intake control valve 26 for opening and closing the first intake port 14b is also provided. The invention further comprises a controller 50 for controlling the opening and closing of the intake control valves 25 and 26, and the degree of opening of these intake control valves 25 and 26 is controlled in accordance with the operating conditions.

Abstract: The invention comprises at least two independent intake ports 14a, 14b connected to a combustion chamber 15, two intake valves 12a, 12b, and two exhaust valves 13a, 13b. A first fuel injection valve 31a is provided in the first intake port 14a and a second intake control valve 26 is provided for opening and closing the second intake port 14b. When the engine is in the cold condition, the second intake control valve 26 is slightly opened and fuel is injected from the first fuel injection valve 31b. Air-fuel mixture from the first intake port 14a and a smaller amount of fresh air from the second intake port 14b are introduced [into the combustion chamber], and the overall air-fuel ratio inside the combustion chamber is controlled to become slightly lean.

Abstract: Axis lines of first and second fuel injection valves are offset from first and second cylinder center lines of first and second combustion chambers by way of moving the first and second fuel injection valves along cam shafts by constituting limits by bringing fuel injection ranges of the first and second fuel injection valves to inner walls of opening portions. Even when the positions of the intake manifolds are obliged to move along the cam shafts, fuel injected from the fuel injection valves can be made to be difficult to adhere to the inner walls of the opening portions and vaporization of fuel can be expedited. Therefore, a mixture in the combustion chambers can be made uniform and engine performance such as response performance of engine rotation, fuel consumption, exhaust gas properties, occurrence of knocking or the like when the throttle valve is opened, can be improved.

Abstract: An electromagnetic valve drive apparatus of an internal combustion engine has a three-switching element in-series type drive circuit. Through switching operations of switching elements that are shared by eight electromagnetic coils consisting of upper coils and lower coils of four valves. The four valves include a first two valves that perform identical operations and a second two valves whose open period does not overlap the open period of the first two valves. The three-switching element in-series type drive circuit is able to supply current and to rapidly reduce, or discontinue, current through the electromagnetic coils. The electromagnetic valve drive apparatus is able to control the quantity of current through the electromagnetic coils while reducing the number of switching elements employed.

Abstract: An internal combustion engine 10 comprises a cylinder 12 including a combustion chamber 17 having at least two air input ports 31, 51 and a piston 18 movable in cylinder 12 so as to vary the volume of combustion chamber 17. An air supply system 20 for supplying combustion air to cylinder 12 comprises first and second air intake systems 30, 50, each including an air passage 33, 53 and a valve 40, 60 controlling air passage through their respective port 31, 51. Each valve is controlled such that second valve 60 is open longer than first valve 40. An air flow valve controller 72 responsive to engine speed and air pressure downstream of a throttle valve 24 moves a valve 81 in second passageway 53 to permit greater air flow through second air passage 53 at higher engine speed and at air pressure less than steady state air pressure for the engine speed.

Abstract: In multi-cylinder engine in which an intake valve and a first spark plug arranged side by side along an axis of a camshaft and an exhaust valve and a second spark plug arranged side by side along the axis of the camshaft are disposed in a cylinder head for every combustion chamber, the position of a central portion of an upstream end of an intake port provided in the cylinder head with the intake valve interposed between the intake port and each of the combustion chambers and the position of a central portion of a downstream end of an exhaust port provided in the cylinder head with the exhaust valve interposed between the exhaust port and each of the combustion chambers are set to correspond with each other in the direction along the axis of the camshaft. Thus, the length of the cylinder head is reduced.

Abstract: The present invention seeks to provide 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: 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: A fuel injection system for a gaseous-fueled engine is provided. The fuel injection system comprises at least one gaseous fuel injector for each of the engine cylinders, wherein each fuel injector is located proximate the intake manifold. A guide tube connects each of the gaseous fuel injectors to at least one of the intake ports. The guide tube comprises a fluid passage arranged within the respective intake port substantially tangent and adjacent to an interior wall of the intake port and directed toward the respective intake valve. The guide tube is adapted to deliver high-pressure gaseous fuel from the injector to the respective combustion chamber along the interior wall of the intake port. In this way, the high velocity peripheral fuel charge creates a lower pressure central core within the intake part which, in turn, increases the overall intake charge flow and engine volumetric efficiency.

Abstract: The invention relates to a variable swirl generating intake manifold with at least one longitudinally oriented partition wall that forms at least one swirl generating first manifold section and one swirl stopping second manifold section, said manifold sections only meeting again in the valve area, at least the second manifold section being, for the purpose of increasing the swirl, at least partially closable in the entrance area by means of a control flap that is pivotal about an axis, said axis being substantially arranged in the plane of the partition wall, said control flap having two arms and said two manifold sections being at least partially closable in a first rotational end position and open in a second rotational end position.

Abstract: A multicylinder petrol engine is provided with a hydraulic system for variable actuation of the valves, which enables easy control of operation of the engine according to different strategies. The engine according to the invention is, in particular, able to operate with a variable engine displacement in a modular way via the exclusion of selected cylinders, to control combustion by means of adjustment of the effective compression ratio, and to control recirculation of the exhaust gases at intake, in order to achieve low levels of consumption and reduced harmful exhaust emissions.

Abstract: So that sufficient combustion air is available in all the cylinders of a diesel internal combustion engine both under part load and in transient operating states, oxygen-containing gas or additional gas or compressed air from a gas distributor is additionally supplied under pressure to the combustion space of the cylinder, even after the diesel internal engine has been started, through at least one separate additional-gas inlet by means of at least one separate additional-gas valve (V1a). The supply of this additional gas can commence after closing of an air inlet valve (VE) or of an air outlet valve (VA) of the diesel internal combustion engine. The method is suitable for both 4-stroke and 2-stroke diesel internal combustion engines.

Abstract: An intake device has a flange, at which it can be attached to a flange of a cylinder head. Intake pipes are furthermore provided, which are configured as at least two inlet ducts per cylinder. At least in the region of the flange of the intake device, the free cross section of at least one of the intake ducts in each case is capable of being closed by a flap. The flange and the flap with a shaft and a bearing are formed in such a way that the flap can be introduced with the shaft and the bearing in front of that side of the flange that faces the cylinder head.

Abstract: The invention relates to a multi-cylinder internal combustion engine with gas flow lift valves actuated by electromagnetic actuators and controlling the intake and the exhaust of the cylinder combustion chambers. The cross-sectional area of the actuators allocated to the intake lift valves which is perpendicular to the axial direction of the lift valves is smaller than the cross-sectional area of the actuators allocated to the exhaust lift valves. If the intake lift valves and the exhaust lift valves are arranged in series one after the other in the direction of the longitudinal axis of the internal combustion engine, the width of the intake actuators measured in the plane of the actuator cross-sectional area and perpendicular to the longitudinal axis of the internal combustion engine is smaller than that of the exhaust actuators.

Abstract: A multi-valve engine comprises a plurality of intake and exhaust valves on a cylinder. Depending on use, one of the valves is made of higher heat-resistant material, and another is made of lower heat-resistant material, thereby decreasing cost and improving durability and reliability.

Abstract: A fuel injection system for a gaseous-fueled engine is provided. The engine comprises a plurality of cylinders each defining a combustion chamber and associated with at least one intake port in fluid communication with an intake manifold and separated from the combustion chamber by an intake valve operable between an open and closed position. The fuel injection system comprises at least one gaseous fuel injector for each of the engine cylinders, wherein each fuel injector is located proximate the intake manifold. A guide tube connects each of the gaseous fuel injectors to at least one of the intake ports. The guide tube comprises a fluid passage arranged within the respective intake port substantially tangent and adjacent to an interior wall of the intake port and directed toward the respective intake valve. The guide tube is adapted to deliver high-pressure gaseous fuel from the injector to the respective combustion chamber along the interior wall of the intake port.

Abstract: A method for selecting which intake valves are operated in an internal combustion with intake valves operated by more than one type of actuation device is disclosed. A criterion for selecting which valves to operate is energy consumed in operating the valvetrain.

Abstract: An intake port configuration (1) for an internal combustion engine wherein 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 are 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 is variable by means of a control element (9), and the two flow paths are constituted by two completely separate intake passages, i.e., a primary passage (2) and a secondary passage (3), the 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, the intake valve axis (5a) intersects or is tangent to the secondary passage (3) at least at one point.

Abstract: The invention relates to an internal combustion engine run on Otto fuel which may be compression ignition operated in a first operational range (HCCI) and spark ignition operated in a second operational range (SI), with means for adjusting valve timing of at least one intake valve (7) and of at least one exhaust valve (8), with at least one ignition equipment (18) and at least one direct injection equipment (17) in each cylinder (1). To permit in the easiest possible way compression ignition and spark ignition operation on Otto fuel, there is provided at least one intake camshaft (9) for actuating the intake valves (7) and at least one exhaust camshaft (10) for actuating the exhaust valves (8), that at least one intake valve (7) in each cylinder (1) is movable between a first and a second lift position by a device for changing the valve lift (11), and that at least one exhaust valve (8) is actuatable by a residual gas recirculation system (13) during the intake lift.

Abstract: A multi-valve engine comprises a plurality of intake and exhaust valves on a cylinder. Depending on use, one of the valves is made of higher heat-resistant material, and another is made of lower heat-resistant material, thereby decreasing cost and improving durability and reliability.

Abstract: An intake valve phase shift in multi-valve engines to enhance air-fuel mixing and optimum combustion at all operating conditions. The intake valve members are independently operated by electro-mechanical actuators or the like, and activated and deactivated by the electronic controller of the engine. A channel or passageway in a diverter member positioned between the two intake ports in the cylinder head allows air and fuel from a closed intake port to be diverted to an open intake port and thus into the combustion chamber. The passageway preferably has a configuration with a certain curvature, orientation and position relative to the diameter of the inlet ports. The curvature is about one-half the diameter D of the inlet port, the passageway is symmetrical from port to port and directs the fuel toward the opposite sides of the ports, and the passageway is positioned about D/4 from the valve seats.

Abstract: A four-stroke internal combustion engine with at least two inlet valves and an inlet flow path with at least two inlet ports per cylinder which branch off from a common inlet pipe and are guided separately up to the inlet valves and of which at least one inlet port is designed as a charge loading port and at least one inlet port as a volumetric port, with a throttle device for volumetric control being provided in the inlet flow path and the inlet flow path is connected with a fuel supply device. In order to achieve in the simplest possible way an improvement of the exhaust gas quality at low fuel consumption, the fuel supply device is formed by a joint carburetor for both inlet ports, with preferably the carburetor being arranged in the zone of the branching of the inlet ports from the inlet pipe.

Abstract: A system and a method to control air flow during a transition in an internal combustion engine, in which intake valves are operated by more than one type of actuation device, is disclosed. Based on demanded engine torque, engine speed and transition type, throttle position and closing time of a randomly operable intake valve are determined such that a smooth transition can be accomplished.

Abstract: In a set of heads for the cylinders of internal combustion engines with desmodromic valve operation, each head comprises an assembly of one or two inlet valves, and an assembly of one or two exhaust valves, so as to form heads with two, three and four valves. The assembly of inlet valves is positioned at an angle to the assembly of exhaust valves. The two assemblies are actuated through respective rockers by a single camshaft located substantially along the line running centrally between the two assemblies. The inlet duct and the exhaust duct are located in the same position within the head and have the same connections to the induction and exhaust systems in all the two-, three- and four-valve versions.

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: An outboard motor includes an internal combustion engine provided with a pair of intake valves. The opening and closing operation of one of the intake valves can be paused. The internal combustion engine comprises a vertical crankshaft, a cylinder head provided with an intake port having a pair of intake openings for one combustion chamber, and a fuel injection valve for injecting the fuel into the intake port. The intake port has an upper branch section and a lower branch section extended under the upper branch section. A valve train includes a valve-operation mode changing mechanism. The valve-operation mode changing mechanism pauses the opening and closing operation of the first intake valve and operates the second intake valve for opening and closing the lower intake opening of the lower branch section while the internal combustion engine is operating at engine speeds in a low-speed range.

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: Within each of: (1) an internal combustion engine system; (2) a transportation vehicle which incorporates the internal combustion engine system; and (3) a method for operating the internal combustion engine system, there is employed: (1) an internal combustion engine having a minimum of one combustion chamber; (2) a gas compressor absent an associated compressed gas tank, where the gas compressor is driven by a power output of the internal combustion engine; and (3) a controller programmed for providing a compressed gas charge from the gas compressor to the minimum of one combustion chamber during a portion of a compression cycle within the minimum of one combustion chamber, but not including a beginning portion of the compression cycle within the minimum of one combustion chamber. Each of the internal combustion engine system, transportation vehicle and method provides enhanced internal combustion engine performance and economy.

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 method for selecting which intake valves are operated in an internal combustion with intake valves operated by more than one type of actuation device is disclosed. A criterion for selecting which valves to operate is energy consumed in operating the valvetrain.

Abstract: An internal combustion engine 10 includes a supercharger 64 and an air supply system 40 including dual intake ports, aspirated air intake port 55 and charged air intake port 75. A piston 18 moveable in an engine cylinder 12 varies the volume of a combustion chamber 17. An exhaust system 80 removes combustion gases 99 from cylinder 12. Aspirated air induction is ceased when the piston displacement reaches approximately 75%-93% of maximum piston displacement. Charged air induction begins as aspirated air induction ceases and continues until piston 18 compresses the inducted air.

Abstract: A method and system for controlling intake valves in an internal combustion with intake valves operated by more than one type of actuation device includes defining operating modes of the intake valve and mapping these onto engine torque and engine speed operating regions. Torque control within regions and steps to accomplish smooth transitions among regions are defined.

Abstract: An internal combustion engine 10 comprises a cylinder 12 including a combustion chamber 17 having at least two air input ports 31, 51 and a piston 18 movable in cylinder 12 so as to vary the volume of combustion chamber 17. An air supply system 20 for supplying combustion air to cylinder 12 comprises first and second air intake systems 30, 50, each including an air passage 33, 53 and a valve 40, 60 controlling air passage through their respective port 31, 51. Each valve is controlled such that second valve 60 is open longer than first valve 40. An air flow valve controller 72 responsive to engine speed and air pressure downstream of a throttle valve 24 moves a valve 81 in second passageway 53 to permit greater air flow through second air passage 53 at higher engine speed and at air pressure less than steady state air pressure for the engine speed.

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 method for influencing the mixture formation and charging movement in the cylinders of a piston internal combustion engine with at least one gas inlet valve and at least one gas outlet valve per cylinder, respectively. Each of these is provided with a fully variable, preferably electromagnetic valve gear and is controllable by means of an electronic control device which is designed in such a way that within predetermined speed ranges and/or in predetermined load conditions, at least some of the gas inlet valves and/or gas outlet valves can be moved in dependence on the piston stroke, respectively, with a stroke course that is variable in relation to opening and closing times and/or opening time for opening width and/or duration of opening period and/or speed of movement.

Abstract: In order to be able to implement low loads at high rotational speeds in an internal combustion engine with electromagnetically activated intake valves, one intake valve of a cylinder is operated in the free flying phase, i.e. not held in the open position, and the other intake valve of the cylinder is correspondingly opened for a longer time. Alternatively, the first valve can also be held closed.

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: An air induction system is arranged to introduce air into a plurality of combustion chambers. The air induction system includes intake passages through which the air flows to the combustion chambers. Throttle valves are arranged to regulate an amount of the air flowing through the intake passages. Auxiliary runners communicate with the intake passages at a location positioned downstream of the throttle valves. The respective runners are unified with each other to form a common chamber. A single conduit has an end communicating with the common chamber and another end communicating with a location that generally is at atmospheric pressure. The air flowing through the conduit, the common chamber and the auxiliary runners also is supplied to the combustion chambers. The common chamber can be positioned next to the intake passages. A control valve can be provided at a location along the single conduit.

Abstract: An intake device has a flange, at which it can be attached to a flange of a cylinder head. Intake pipes are furthermore provided, which are configured as at least two inlet ducts per cylinder. At least in the region of the flange of the intake device, the free cross section of at least one of the intake ducts in each case is capable of being closed by a flap. The flange and the flap with a shaft and a bearing are formed in such a way that the flap can be introduced with the shaft and the bearing in front of that side of the flange that faces the cylinder head.

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: In an internal combustion engine equipped with a pair of intake ports for each cylinder and capable of controlling a quantity of air entering the engine by controlling an intake valve open timing and an intake valve closure timing of each of a pair of intake valves located in the respective intake ports, a two-intake-valve operating mode is used in a high-load, high-speed operating range, whereas a one-intake-valve operating mode is used in predetermined low- and mid-load, low- and mid-speed operating ranges to create a great gas flow within the cylinder. A fuel injector is located in a first one of the intake ports to allow air flow through the first intake port over all operating ranges.