Suzuki Jidosha Kogyo Kabushiki Kaisha

Suzuki Motor Company

Mikuni Kogyo Kabushiki Kaisha

Tokuzi Ishida

Hiroshi Yokoyama

Kunio Kikuchi

Wataru Yamamoto

Kazuaki Zama

Kiyotaka Aono

An intake port structure comprises a cylinder head including combustion chambers and supporting an intake valve and an ignition plug in each of the combustion chambers, the intake valve having a stem slidably supported by the cylinder head, the cylinder head having a joint surface to which an intake manifold is connected. A primary intake passage is defined in the cylinder head and communicates with each of the combustion chambers, the primary intake passage having a primary intake port directed toward the stem and the ignition plug, and an opening at the joint surface. The opening has a central axis extending at an angle smaller than 90.degree. with respect to the joint surface. The primary intake passage is smoothly curved between the primary intake port and the opening. The intake manifold has a plurality of primary manifold branches arranged substantially symmetrically with respect to a central axis of the intake manifold.

Intake port structure for internal combustion engines

An air-fuel mixture intake apparatus for internal combustion engines includes a two-barrel carburetor having a primary venturi for supplying an air-fuel mixture into a combustion chamber under all loads and a secondary venturi for supplying an air-fuel mixture into the combustion chamber under medium and high loads. The primary venturi is of a fixed cross section and the secondary venturi is of a variable cross section. A vacuum-operated actuator controls operation of a secondary throttle valve in response to a vacuum developed in the primary venturi and subsequently in the secondary venturi. The secondary throttle valve is interlinked with a primary throttle valve by a linkage mechanism such that the secondary throttle valve is allowed to open when the primary throttle valve opens to a predetermined degree with the maximum opening of the secondary throttle valve being variably controlled by the opening of the primary throttle valve after the latter has opened beyond the predetermined degree. A delay valve is disposed in a primary vacuum signal passageway or a common vacuum signal passageway connected to a vacuum chamber of the vacuum-operated actuator to delay an air flow through the passageway toward a vacuum pickup probe in the primary venturi. The secondary throttle valve may be mounted on a shaft displaced downstream off the geometric center of the secondary throttle valve.

Air-fuel mixture intake apparatus for internal combustion engines

An accelerator pump supplies additional fuel into a primary intake passage when a primary throttle valve is opened. A vacuum-operated actuator is responsive to a vacuum developed in a manifold passage upon cranking for actuating an accelerator pump plunger to discharge extra fuel into the primary intake passage. When the engine which is cold is to be started, such an additional supply of fuel assists the engine in getting started quickly. When the engine which is hot is to be restarted, the actuation of the accelerator pump clears away fuel vapor from the accelerator pump and a fuel feed passage connected therewith, thus readying the accelerator pump for normal operation. The primary throttle valve is operatively connected to the accelerator pump through a plate cam having a cam edge which is profiled such that the amount of extra fuel as supplied by the accelerator pump is proportional to opening of the primary throttle valve.

Accelerator pump system for carburetors

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.

Intake passage structure for internal combustion engines

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. According to another embodiment, a plurality of induction passages are provided respectively for combustion chambers and connected to a common passage which communicates with primary intake passages immediately downstream of a primary throttle valve and also with a slow fuel supply passageway in the secondary intake system. The induction passages comprise pipes opening into secondary intake passages, respectively, immediately upstream of secondary throttle valves. When the engine operates, the induction passage ejects air or an air-fuel mixture into the combustion chambers at high speeds to thereby form swirls therein for promotion of fuel combustion. With fuel supplied continuously from the slow fuel supply passageway into the induction passage, there is no danger for vapor lock to take place within the slow fuel passageway.

Air-fuel mixture intake construction for internal combustion engines

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. The primary passage extends through a region where the secondary passage is divided into a plurality of secondary branches, and is located immediately in front of the shortest one of the secondary branch. The primary passage is also branched into a plurality of primary branches, the shortest of which is displaced out of axial alignment with a central axis of the intake manifold.

Duplex carburetor and intake system for internal combustion engines

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.

Intake passage construction for internal combustion engines

A throttle valve is opened upon engine cranking through a predetermined angle by a vacuum-operated valve in response to a vacuum signal supplied thereto from a vacuum pickup port positioned downstream of the throttle valve, for assisting the engine in getting started quickly and stably. A directional control valve is actuated upon engine cranking to allow the vacuum signal to be fed to the vacuum-operated valve. The vacuum pickup port communicates with the vacuum-operated valve through vacuum passages having thermosensitive valves one openable when the engine is kept below a preset temperature and the other openable when the engine temperature is above the preset level. A pressure delay means may be connected between the vacuum pickup port and the vacuum-operated valve to delay closing of the latter after the engine cranking.

Throttle control system for internal combustion engines

An internal combustion engine has a primary intake passage including a primary throttle valve for supplying engine cylingers with an air-fuel mixture under a full range of loads, a secondary intake passage including a secondary throttle valve for supplying the engine cylinders with an air-fuel mixture under high loads, and an exhaust-gas recirculation passage including an exhaust-gas recirculation valve for introducing an exhaust gas into the primary intake passage. Vacuums at the primary and secondary throttle valves are utilized to control the exhaust-gas recirculation valve. A distributor for producing ignition sparks is also controlled by the vacuums at the primary and secondary throttle valves for ignition timing. The engine also includes a first mechanism for retarding ignition sparks and a second mechanism for promoting engine idling. When the exhaust-gas recirculation valve is controlled, the second mechanism is released, immediately thereafter air is introduced from the secondary intake passage into the primary intake passage for air-fuel ratio control therein, and the first mechanism is released. When the secondary intake passage comes into operation, fuel vapor is introduced from a canister into the secondary intake passage.

Method of controlling EGR for internal combustion engines

A compound carburetor wherein, in order that, in the course of the transit from the primary side to the secondary side, an air-fuel mixture fed to each cylinder may maintain a uniform air-fuel ratio without causing an air lock and the transit may be made smoothly and definitely, an independent secondary slow-running fuel system is provided for each cylinder and a secondary slow mixture path includes in the course a pipe connected between a carburetor part and manifold part.

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Hamamatsu, Japan

Tokuzi Ishida