Abstract: An intake manifold for an internal combustion engine having a plurality of cylinders is composed of a primary intake manifold assembly including a plurality of primary branch pipes extending from a two-barrel carburetor to the cylinders, respectively, and a secondary intake manifold assembly including a plurality of secondary branch pipes extending from the two-barrel carburetor to the cylinders, respectively. The primary and secondary branch pipes are joined together immediately upstream of intake ports opening into the combustion chambers. The primary and secondary branch pipes are dimensioned to meet the relationship of (n-1)S.sub.1 .ltoreq.S.sub.2 where S.sub.1 is the cross-sectional area of each of said primary branch pipes, S.sub.2 is the cross-sectional area of each of said secondary branch pipes, and n is the number of said cylinders.

Abstract: An engine comprising an intake port which has a separating wall projecting downward from the upper wall of the intake port. The separating wall defines a helical portion, an inlet passage portion tangentially connected to the helical portion, and a bypass passage interconnecting the inlet passage portion to the helical portion. A rotary valve is arranged in the bypass passage and actuated by a vacuum operated diaphragm apparatus. The rotary valve is opened when the amount of air fed into the cylinder of an engine is increased beyond a predetermined value. The separating wall has a height which is equal to approximately half the height of the intake port in the vicinity of the rotary valve.

Abstract: An engine comprising an intake port which has a separating wall projecting downwardly from the upper wall of the intake port. The separating wall defines a helical portion, an inlet passage portion tangentially connected to the helical portion, and a bypass passage interconnecting the inlet passage portion to the helical portion. A rotary valve is arranged in the bypass passage and actuated by a vacuum operated diaphragm apparatus. The rotary valve is opened when the amount of air fed into the cylinder of an engine is increased beyond a predetermined value. A downwardly projecting rib is formed on the bottom face of the separating wall. The rib extends toward the helical portion from the rotary valve.

Abstract: The present invention is directed to a valve operation control apparatus for use in an internal combustion engine. The device comprises a cylinder with at least two intake or two exhaust valves, one of the two valves including a pause member for holding the valve in a closed position. The control apparatus comprises a control circuit operatively coupled to the pause member. The control circuit has at least two open degree sensors responsive to two different degrees of opening of a throttle valve of the engine and at least two engine speed sensors responsive to two different speeds of the engine, wherein the control circuit controls the operation of the pause member in response to predetermined combinations of the operation of the open degree sensors and the engine speed sensors.

Abstract: An intake passage structure for an internal combustion engine includes a primary air-fuel mixture passage disposed remotely from a water jacket located below a secondary air-fuel mixture passage. A secondary slow fuel supply passage extends from a float chamber adjacent to the primary air-fuel mixture passage so that fuel in the secondary slow fuel supply passage will be cooled by an air-fuel mixture flowing through the primary air-fuel mixture passage, thereby preventing vapor lock from occuring in the secondary slow fuel supply passage. The primary air-fuel mixture passage is composed of a common passageway, a distribution slot and branch slots for supplying an air-fuel mixture to engine cylinders. The distribution and branch slots are closed by a cylinder head. Any liquid fuel in the distribution and branch slots are vaporized with heat from the cylinder head.

Abstract: A suction system for an internal combustion engine which is equipped with a sub-suction path provided separately from a main suction path for generating a swirl of the gases in a combustion chamber during the suction stroke. The amount of the air to be supplied via the sub-suction path to the combustion chamber is less than 40% preferably from 10 to 40%, more preferably from 20 to 30% of the total amount of the air to be supplied to the combustion chamber. Alternatively the effective area of the sub-suction path at its outlet end is 0.2 to 3.0% of that of the main suction path.

Abstract: An engine comprising an intake port which has a separating wall projecting downward from the upper wall of the intake port. The separating wall defines a helical portion, an inlet passage portion tangentially connected to the helical portion, and a bypass passage interconnecting the inlet passage portion to the helical portion. A rotary valve is arranged in the bypass passage and actuated by a vacuum operated diaphragm apparatus. The rotary valve is opened when the amount of air fed into the cylinder of an engine is increased beyond a predetermined value. A conical shaped groove is formed on the bottom wall of the intake port. The lower end of the rotary valve is located in the groove.

Abstract: A secondary air introducing device for an engine including a cylinder, an associated piston, and a secondary air introducing hole formed in a side wall of the cylinder in such a manner that said hole is located near the bottom dead center of the piston and is opened and closed by the piston. The secondary air introducing hole is made to communicates through inlet passages with the atmosphere, so that the external air is introduced into the cylinder through the secondary air introducing hole by a negative pressure which is produced in the cylinder at the end of a suction stroke of said engine, and a control valve means opened and closed according to variations in load of the engine is provided in the inlet passages, thus controlling an amount of air introduced therein.

Abstract: An induction system for an internal combustion engine having main induction passages and relatively small cross-sectional area auxiliary induction passages for delivering a charge from a carburetor to the combustion chambers. A control valve arrangement is provided so that the engine charge requirement at idle and low load are supplied through the small auxiliary induction passages so as to increase turbulence in the combustion chamber at the time of combustion. The inlet to the auxiliary induction passage is disposed in the path of fuel discharge from the idle circuit of the associate carburetor so as to improve mixture distribution and promote smooth running. The inlet for the auxiliary induction passage is also positioned at a higher point than the control valve so as to reduce the likelihood of liquid fuel being drawn into the auxiliary induction system. The inlet for the auxiliary system is also heated to improve vaporization.

Abstract: A valve apparatus of a solenoid drive type having a valve member in a housing defining an inlet port and first and second outlet ports. The valve member connects the inlet port to the second outlet port while closing the first outlet port when no electric current is received by the apparatus. The valve member controls the opening of the first outlet port while maintaining the second outlet port closed when an electric current larger than a predetermined offset value is applied to the apparatus. When the electric current is equal to the offset value, the valve member closes both the first and the second outlet ports.

Abstract: A helically-shaped intake port comprising a helical portion formed around an intake valve, and a substantially straight inlet passage portion tangentially connected to the helical portion. A bypass passage is branched off from the inlet passage portion and connected to the helical portion. A slide valve is arranged in the bypass passage and controlled by a stepper motor so that the opening area of the slide valve changes in proportion to the amount of air to be fed into the cylinder of the engine.

Abstract: An air-fuel mixture intake construction for an internal combustion engine comprises a primary intake system for supplying an air-fuel mixture under a full range of engine loads, a secondary intake system for supplying an air-fuel mixture under medium and high engine loads, and an induction passage having one end opening into a secondary intake passage immediately upstream of a secondary throttle valve disposed therein, and the other end opening immediately upstream of an intake valve for a combustion chamber. The open end of the induction passage in the secondary intake passage is spaced inwardly from an inner wall surface of the secondary intake passage to prevent fuel in liquid form from flowing into the induction passage from the secondary intake passage.

Abstract: An intake manifold for a spark-ignited internal-combustion engine including a distributor body from which the intake pipes leading to the individual combustion chambers of the engine branch off in a sequence corresponding to the firing order. The individual intake pipes depart, via branch lines, from more than one location of the distributor body. Preferably, the locations of the distributor body associated with a respective intake pipe are arranged in symmetry with respect to an axis of the distributor body.

Abstract: An intake port structure for an internal combustion engine having a primary intake passage defined in a cylinder head for supplying an air-fuel mixture into a combustion chamber in a full range of loads, and a secondary intake passage defined in the cylinder head for supplying an air-fuel mixture into the combustion chamber under relatively high load conditions. The primary intake passage has a first outlet port opening into the secondary intake passage immediately upstream of the valve face of an intake valve. The secondary intake passage has a second outlet port opening into the combustion chamber through the valve face. A wall projects sidewardly into the secondary intake passage adjacent to the second outlet port for deflecting an air-fuel mixture flowing from the secondary intake passage into the combustion chamber to form a swirl of air-fuel mixture in the combustion chamber.

Abstract: An improved induction system for a V type engine that improves both charging and combustion efficiency. The engine includes an induction system for each cylinder barrel that includes a pair of intake valves and respective intake passages that have a common inlet. One of the intake passages is curved and an auxiliary intake passage extends through the cylinder head and terminates at an auxiliary intake port that is disposed at one side of the main intake port in proximity to the cylinder barrel for generating a swirl to the intake charge. A plenum chamber is position in the V of the engine and defines two separate chambers each of which communicates with a respective one of the auxiliary intake passages.

Abstract: Internal combustion engine constituted such that two inlets are provided to a sub-suction path which is provided separately from the main suction path and serves to inject gas such as air or air-fuel mixture at high velocity in the peripheral direction of a combustion chamber at the suction stroke; one of said inlets is located upstream of the throttle valve, the other located in the air path of the carburetor at a position where the throttle valve can be shut in time of idling, wherein the effective opening area of the throttle valve can be enlarged through appropriate number and form of the inlets to be shut by the throttle valve and the downstream side inlet of the two inlets is set to be within the range of an angle, i.e., the downstream side inlet is located within the range of 60.degree.-120.degree.

Abstract: A secondary air introducing apparatus for an internal combustion engine comprising a secondary air introducing opening in the sidewall of the cylinder near the position of lower dead point of a piston of the engine. The opening is opened and closed by the piston. A secondary air supply source is interconnected with the opening by an introducing passage. The introducing passage is formed to be an upwardly directed passage extending only upwards from the opening.

Abstract: In a fuel controller which comprises; a venturi portion formed in an air-intake path adapted to feed air to an internal combustion engine; a throttle valve installed on the downstream side of the venturi portion; an auxiliary throttle valve and a fuel injection portion provided between the throttle valve and the venturi portion; a bypass air path opened at the venturi portion and at the upstream side thereof; a hot-wire type air flow sensor provided in the bypass air path for detecting an amount of air passing therethrough; and a proportional electromagnetic device which controls the amount of air passing through the bypass air path at a constant level with an air needle valve provided therein and which controls an amount of fuel passing through a fuel path corresponding to an amount of air passing through the air-intake path with a fuel needle valve provided in the fuel path communicating with the fuel injection portion, the auxiliary throttle valve and the throttle valve are operated interlockedly through a

Abstract: A helically-shaped intake port comprising a helical portion formed around an intake valve, and a substantially straight inlet passage portion tangentially connected to the helical portion. A bypass passage is branched off from the inlet passage portion and connected to the helical portion. A rotary valve is arranged in the bypass passage and actuated by a vacuum operated diaphragm apparatus. The vacuum chamber of the diaphragm apparatus is selectively connected to the atmosphere or the suction pump driven by the diesel engine for opening the rotary valve when the level of load of the diesel engine is increased beyond a predetermined level.

Abstract: A helically-shaped intake port comprising a helical portion formed around intake valve, and a substantially straight inlet passage portion tangentially connected to the helical portion. A bypass passage is branched off from the inlet passage portion and connected to the helical portion. A rotary valve is arranged in the bypass passage and actuated by a vacuum operated diaphragm apparatus. The vacuum chamber of the diaphragm apparatus is connected to the interior of the intake manifold via a vacuum port and a check valve cooperating with the vacuum port. The check valve opens the vacuum port when the level of vacuum in the intake manifold becomes greater than that of vacuum in the vacuum chamber. In addition, the vacuum chamber is connected to the atmosphere via an atmosphere port and an air valve cooperating with the atmosphere port. The air valve opens the atmosphere port when the level of vacuum in the venturi portion of the carburetor becomes greater than a predetermined level for opening the rotary valve.

Abstract: A fuel economizer device for use with an internal combustion engine fitted with a carburetor is disclosed. The fuel economizer includes a plate member which is mounted between the carburetor and the intake portion of the intake manifold. The plate member further has at least one aperture formed therein. One tube is inserted through the at least one aperture in the plate member. The one tube extends longitudinally in the passage of the intake manifold from the intake portion toward the exit portion thereof. The one tube concentrates the mixture of fuel and air from the carburetor and conveys the mixture of fuel and air to a point adjacent but spaced away from the inlet port of the internal combustion engine.

Abstract: A duplex carburetor for an internal combustion engine has a primary barrel having a primary venturi for supplying an air-fuel mixture to an intake manifold under a full range of engine loads and a secondary barrel having a secondary venturi for supplying an air-fuel mixture to the manifold under higher engine loads. The primary venturi has a cross section which ranges from 20% to 30% of that of the secondary venturi. The secondary barrel has a flattened cross-sectional shape such as of a segment of a circle of an ellipse, and is located adjacent to the primary barrel. The intake manifold is of a duplex construction having primary and secondary common passages connected to the primary and secondary barrels, respectively, of the carburetor. The secondary passage of the manifold has a flattened cross-sectional shape such as of a segment of a circle or an ellipse, and is positioned adjacent to the primary passage.

Abstract: An internal combustion engine which devises the opened direction and position of the gas outlet end of a sub-suction path provided separately from a main suction path so as to inject a gas in the circumferential direction of a combustion chamber during the suction stroke, in which the outlet end of the sub-suction path opens within such a range that, in a plane normal to the axis of the cylinder, the line extending in an opened direction of the sub-suction path is at an angle of .+-.20 to 110 degrees with respect to the line joining the center of the suction port and the axis of the cylinder; the distance between the outlet end of the sub-suction path and the face of a suction valve at its closed position is not more than the internal diameter of the main suction path; or the outlet end of the sub-suction path is positioned within a sphere with its center being a spark point of an ignition plug and with the same diameter as the internal diameter of the cylinder and within a range of .+-.

Abstract: An intake system of an internal combustion engine having at least two intake ports formed in the cylinder head. Each of the intake ports comprises an inlet port portion and a port terminating portion formed around the valve stem of the intake valve. Each of the inlet port portions has an opening which is open to the corresponding port terminating portion. The port terminating portions are interconnected to each other via a common connecting passage. The common connecting passage has opposed end openings, each being open to the corresponding port terminating portion at a position opposite to the opening of the corresponding inlet port portion with respect to the valve stem of the corresponding intake valve.

Abstract: An intake passage construction for an internal combustion engine has a primary intake passage for supplying an air-fuel mixture when the engine operates under a full range of loads and a secondary intake passage for supplying an air-fuel mixture when the engine operates under relatively high loads. A secondary slow fuel passage has a pair of fuel supply ports opening into the secondary intake passage, and a fuel drain passageway extends from one of the fuel supply ports and has a fuel discharge port opening into the primary intake passage. Ambient air can be introduced into the fuel drain passageway in response to a vacuum developed in the primary intake passage so that fuel can be drained from the secondary slow fuel passage to prevent vapor lock therein. The fuel discharge port of the fuel drain passageway may open into an induction pipe.

Abstract: A control for carburetor-supplied induction systems for internal combustion engines. The engine includes a carburetor and a principal induction passage leading to an intake valve and thence to a combustion chamber. A principal throttle in the carburetor controls the supply of air/fuel mixture to the principal induction passage as a function of throttle setting and engine demand. This invention includes an auxiliary throttle valve in the principal induction passage between the principal throttle and the intake valve, and an auxiliary induction passage extending from a point in the principal induction passage between the two throttles to a point adjacent to the intake valve where its discharge will, when the intake valve is open, enter the combustion chamber in such a way as to cause swirl and/or turbulence. The auxiliary throttle is closed at light loads so that the bulk of the intake charge is delivered to the combustion chamber through the auxiliary induction passage.

Abstract: An intake system of an internal combustion engine including a power cylinder having an intake valve and a fuel injection nozzle, comprising: a throttle chamber upstream open to the atmosphere; primary and secondary throttle valves provided in parallel with each other in the throttle chamber; primary and secondary air passageways leading from the throttle chamber past the primary and secondary throttle valves, respectively, and conjoined together upstream of the intake valve, the secondary passageway being larger in cross sectional area than the primary air passageway and having a reservoir chamber portion larger in cross sectional area than the remaining portion of the secondary passageway; and air heating means provided in the primary air intake pipe and operative to preheat the air to be passed through the primary air intake pipe.

Abstract: A multi-cylinder engine comprising a carburetor housing forming therein at least two branch mixture passages. Each of the branch mixture passage is connected to a respective intake port. A throttle valve of the carburetor is provided for each cylinder. Each of the throttle valves is arranged in the respective branch mixture passage. A common connecting passage and branch connecting passages which are connected to the common connecting passage are provided. Each of the branch connecting passages opens into the respective intake port located downstream of the corresponding throttle valve. Another common connecting passage is provided. The branch mixture passages located upstream of the throttle valves are interconnected to each other via the other common connecting passage.

Abstract: An internal combustion engine having a plurality of main suction paths adapted to respectively communication with a single combustion chamber are so provided that they can be opened or closed by different suction valves and in which a plurality of sub-suction paths provided separately of the main suction paths are pointed directing to the single combustion chamber so that the gases injected therefrom during the suction stroke may be swirled in an identical circumferential direction within said identical combustion chamber.

Abstract: A helical type intake port is formed with the helical portion around an intake valve and the inlet portion tangentially contiguous to the helical portion.A bypass passage is provided in a cylinder head, which is branched off from the inlet portion and connected to an end portion of said helical portion. The flow in the bypass passage is controlled by a valve in response to the amount of air in the intake port so that a strong swirl flow with a slight flow resistance may be obtained at not only a low revolution and a low load, but also at a high revolution and a high load.

Abstract: An internal combustion engine is described in which the shape and construction of the gas outlet end portion of a sub-suction path is made operative to inject a gas such as air, an air-fuel mixture or exhaust gas circumferentially into the combustion chamber during the suction stroke. The gas outlet end portion has a reduced diameter and an injection nozzle which has a length greater than its internal diameter. Moreover, the gas outlet end portion is constructed of a pipe member which is rotatably and adjustably fitted into the insertion hole of a cylinder head and which is so shaped that the open direction of the outlet end thereof can be changed when it is rotationally adjusted.

Abstract: A helical type intake port for an internal combustion engine. The system has a first sub-intake passageway and a second sub-intake passageway. The first sub-intake passageway is connected to a helical end of the intake passageway for generating a flow of air for suppression of the swirl effect in the helical end. The second sub-intake passageway is connected to a portion of the helical port located upstream of the helical end portion, for increasing the speed of flow of air directed to the helical end portion.

Abstract: An improved intake system for an internal combustion engine is disclosed which includes a combustion chamber, an intake passage and an exhaust passage opening to the combustion chamber, and an intake valve and an exhaust valve disposed in the intake and exhaust passages for opening and closing thereof. The system is featurized by provision of one or more control passage(s) opening to the intake passage in the vicinity of the intake valve, and a supply chamber of a predetermined volume which is in communication with the control passage(s). The system is particularly effective in improving the intake efficiency in small-sized, four stroke cycle engines.

Abstract: A multi-cylinder internal combustion engine is disclosed in which a portion of the exhaust gas is selectively added to each cylinder. The exhaust gas is caused to swirl along the inside wall of the cylinder. Air or a fuel/air mixture is caused to swirl in a central zone in the cylinder in the same direction of swirl as the direction of swirl of the exhaust gas thereby providing a stratified exhaust gas recirculation design.

Abstract: An induction system for an internal combustion engine including an auxiliary induction system formed by a spacer and a plurality of pipes extending from the spacer into each of the engine cylinder head main intake passages. Each pipe is formed with a deflector portion at its end so that a charge will be delivered directly to the chambers of the engine from the pipes without impingement upon the cylinder head surfaces.

Abstract: An induction system and carburetor for a high performance internal combustion engine wherein a pair of separate intake passages serve each of the engine chambers. The carburetor has separate barrels, one for each intake passage and which have a fuel discharge circuit therefor. The fuel discharge circuits for each of the carburetor barrels is supplied by a common fuel source.

Abstract: An internal combustion engine comprising a main intake passage supplying air-fuel mixture to a combustion chamber, an auxiliary intake passage supplying air or an air-fuel mixture to the combustion chamber through an injection port, a fuel supplement passage for supplementally supplying fuel to the auxiliary intake passage, a solenoid valve provided in the fuel supplement passage, and a control device for controlling opening and closing of the solenoid valve in response to a signal from an oxygen sensor disposed in an exhaust passage, said solenoid valve controlling supply of fuel to the auxiliary intake passage, thereby regulating an overall air-fuel ratio of the mixture supplied to the combustion chamber approximately to a stoichiometric air-fuel ratio.

Abstract: A device for improving combustion efficiency of mixture in a four cycle internal combustion engine is disclosed in which burnt gas is introduced, upon the intake stroke, into a combustion chamber from an exhaust passage to generate a swirl whereby fresh mixture supplied from an intake port to the combustion chamber is disturbed to form a strong swirl. To this end, the valve opening periods of intake and exhaust valves are partially overlapped with each other and a swirl generating guide wall is formed around an exhaust port and extends inwardly from the combustion chamber wall so that a part of burnt gas flows back, upon the intake stroke, into the combustion chamber through the exhaust port unclosed by the exhaust valve to impinge against the guide wall thereby to generate a swirl. A portion of the exhaust passage leading to the exhaust port may extend in a direction offset from the center of the combustion chamber so as to promote the generation of a swirl.

Abstract: An internal combustion engine having a cylinder block comprising one cylinder or a plurality of cylinders, a piston reciprocable in each cylinder, a crank shaft, a cylinder head with inlet and exhaust valves, inlet and exhaust conduits, an ignition or injection device and valve timing means operatively associated with the cylinder head, fuel supply means in communication with the engine intake side, a feed line for supplying a pressurized or ambient air pressure additional fluid such as a gaseous or a liquid fluid to the cylinders of the engine toward a location upstream of the inlet valve seat(s). The feed line outlet may be formed as a Venturi tube. The feed lines and portions of the intake and exhaust conduits may be incorporated into an intermediate flange member adapted to be mounted on the engine block intermediate the intake/exhaust conduits and respective associated intake/exhaust manifolds. The feed lines may include non-return valve means.

Abstract: Disclosed is a fuel/air mixture supply system for an internal combustion engine of the single-point fuel injection type wherein, the intake manifold system is formed with a first fuel/air supply passage which inspires atmospheric air and which has fitted generally at a midpoint thereof a fuel injection valve which injects fuel into the inspired air. The fuel/air mixture then proceeds to a first set of branched passages, each one of which conducts the fuel/air mixture to a cylinder of the engine. Further, there is provided a second air supply passage which inspires atmospheric air and which branches into a second set of branched passages, each one of which conducts air to a cylinder of the engine. The first fuel/air supply passage is smaller than the second air supply passage, and the first set of branched passages are smaller than the second set of branched passages.

Abstract: An induction system for a multi-cylinder internal combustion engine that improves fuel efficiency and reduces the emission of unwanted exhaust gas constituents, particularly at the low and medium load conditions. The engine induction system comprises a plurality of separate carburetor barrels which, at least under some running conditions, serve cylinders separately from each other through main induction passages. One carburetor barrel is provided with a different fuel discharge system than the other carburetor barrels for accommodating a certain engine operating condition. A separate sub-intake system connects this carburetor barrel with other cylinders not normally served by the particular carburetor barrel in question. This sub-intake system has a substantially smaller cross-sectional area in the main intake system so that the charge drawn into the cylinders through the sub-intake system enters at a substantially higher velocity.

Abstract: An internal combustion diesel engine having a piston sliding in a cylinder and forming a main combustion chamber between the piston and the cylinder head. The cylinder head also has a pre-combustion chamber which communicates by a connecting passage with the main combustion chamber, with a fuel injection nozzle and glow plug arranged to project into the pre-combustion chamber. In addition, a smaller auxiliary chamber is provided which communicates with the pre-combustion chamber by a nozzle shaped aperture, and supplies additional combustion air to the pre-combustion chamber to help effectuate complete combustion, even at high engine loads, of the air-fuel mixture.

Abstract: An internal combustion engine of the four cycle reciprocating piston type wherein intake and exhaust of working fluid and combustible fuel into the engine is primarily by means of valves in the cylinder head, and secondarily by means of an intake port in open communication with the lower portion of the cylinder chamber for the induction of additional gases for the support of combustion, and preferably a combustible mixture controlled by valve means for induction only.

Abstract: A multi-cylinder engine comprising a carburetor housing forming therein at least two branch mixture passages. Each of the branch mixture passages is connected to a respective intake port. A throttle valve of the carburetor is provided for each cylinder. Each of the throttle valves is arranged in the respective branch mixture passage and attached onto a common throttle shaft. A wedge shaped groove is formed on the bottom wall of each of the branch mixture passages, and the common throttle shaft is arranged in the wedge shaped groove for causing the mixture to flow only along the upper wall of the branch mixture passage. A single common connecting passage and branch connecting passages which are connected to the common connecting passage are provided. Each of the branch connecting passages opens into the respective intake port in the vicinity of the rear face of the valve head of the corresponding intake valve.

Abstract: An induction system for a multiple cylinder internal combustion engine embodying a simplified fuel injection arrangement that reduces the number of injection nozzles. The engine is provided with a relatively large cross sectional area main induction system and a relatively small cross sectional area auxiliary induction system. A valving arrangement is incorporated so that a major portion of the engine charge requirements are supplied to the chambers through auxiliary induction system at idle and low speed. As a result, turbulence in the combustion chamber at the time of ignition is increased to provide improved fuel economy and exhaust emission control. One fuel injection nozzle is positioned in an inlet passage of the auxiliary induction system which serves a plurality of chambers. In this way, one injection nozzle can serve multiple chambers without adversely affecting mixture distribution.

Abstract: An internal combustion engine having a relatively large main induction system which supplies a charge to the chambers at higher loads and a relatively small auxiliary induction system that supplies the chamber charge at idle and low loads so as to improve fuel economy and exhaust emission control. A valve arrangement is incorporated for controlling the flow through the induction systems. The valve arrangement includes a manually positioned valve and a valve that is responsive of flow through the induction passages so that an increasing proportion of the charge will be supplied through the main induction system as the air flow increases. A manual override is also included so that the automatically positioned valve will be opened independently of the air flow responsive actuator when the manually operated throttle valve is suddenly opened.

Abstract: Several embodiments of induction systems for multiple cylinder internal combustion engines that improve engine performance, particularly at idle and low speed. In each embodiment a charge is delivered to the chambers at idle and low speed through a relatively small cross sectional area auxiliary induction system for improving turbulence in the chamber at the time of combustion. The auxiliary induction passages communicate with each other so that the idle charge for a given chamber that is on its intake cycle will be supplied from the portion of the other induction systems downstream of a manually operated throttle valve. Upstream of the manually operated throttle valves there is provided another throttle valve which cooperates with an idle fuel discharge so that the idle fuel is delivered to the various chambers.

Abstract: An internal combustion engine comprising an intake duct and a turbocharger arranged in the intake duct. A primary throttle valve connected to the accelerator pedal is arranged in the intake duct located downstream of the turbocharger. A secondary throttle valve is arranged in the intake duct located downstream of the primary throttle valve. An auxiliary intake passage is branched off from the intake duct located between the primary and the secondary throttle valves and is connected to the intake passage located downstream of the secondary throttle valve. The secondary throttle valve is gradually closed from the full open position as the level of the vacuum or the positive pressure, which are produced in the intake duct located between the primary and the secondary throttle valves, is increased.

Abstract: A high power output internal combustion piston engine is provided with two intake ports and one exhaust port for each combustion chamber. Flow through each port is controlled by a valve, the exhaust valve being positioned on one side of the combustion chamber and the two intake valves on the other side. A spark plug communicates with the combustion chamber on the same side as the exhaust valve, and near one of the intake valves. An air-fuel mixture is supplied to each of the intake ports through first and second throttle valves. Means including a lost-motion connection coordinates the movements of the throttle valves.

Abstract: A multi-cylinder engine comprising a carburetor housing forming therein at least two branch intake passages. Each of the branch intake passages is connected to a respective intake port. A throttle valve of the carburetor is provided for each cylinder. Each of the throttle valves is arranged in the respective branch intake passage. A single common passage and branch connecting passages which are connected to the common passage are provided. Each of the branch connecting passages opens into the respective intake port in the vicinity of the rear face of the valve head of the corresponding intake valve.