Abstract: A two-cylinder two-stroke internal combustion engine is provided with insed cylinder liners carrying separate thin-walled cooling jackets. In the area of the intake and exhaust ports the walls of the liners are thickened in order to improve the directing of the inflowing charge and to facilitate a leak-proof attachment of the cooling jackets.The areas of the two cylinder liners facing each other are not thickened nor do they have any ports; they are only provided with a collar continuing the upper edge of the thickened portion and serving for the leak-proof attachment of the cooling jacket, such that the space between the cylinders lying below this collar may be utilized for the exchange of fresh charge between the two longitudinal sides of the engine, without the need for an increase of the distance between the cylinders.

Abstract: The tappet of the invention includes two movable elements defining between them a chamber which can be filled with oil arriving through at least one suitable duct from a source of oil under pressure; along this duct there is disposed an interception member comprising a ball able to cooperate with a corresponding seat into which the said duct opens.

Abstract: The present invention features a variable valve timing arrangement having a zero valve clearance maintaining device which takes the form of either a springy finger-like extension provided on a valve timing control lever, which extension biases a rocker arm which operates the valve, against the valve stem until the rocker arm has been cammed to pivot by a predetermined amount; or an eccentric bush on which the control lever is mounted and a telescopic hydraulic cylinder arrangement which rotates the bush to press the lever against the rocker arm with a predetermined force adequate for maintain a zero valve clearance.

Abstract: A combustion engine has at least one balancer shaft, driven by the engine and arranged parallel to the crankshaft, to dampen engine vibrations. The balancer shaft is arranged in a separate housing, mounted on the outside of the cylinder block, to make it possible, with only minor modifications, to equip existing older engine types with balancer shafts. The housing has at least two axially-spaced bearings for the balancer shaft and is attached directly to the engine block by means of fasteners located in the area of those bearings.

Abstract: A valve actuating device for an internal combustion engine having a cam and a valve stem comprises a rocker arm receiving a load from the cam at one end and actuating the valve stem at the other end thereof, a hydraulic valve lifter slidably disposed in the rocker arm, a hollow rocker arm shaft pivotally supporting the rocker arm, a first fluid supply passage formed in the rocker arm shaft, a second fluid supply passage formed in the rocker arm, and an air hole formed in an upper portion of the hollow rocker arm shaft.

Abstract: An internal combustion engine having a plurality of cylinders each comprising a first intake valve, a first intake passage connected to the corresponding cylinder via the first intake valve, a second intake valve, and a second intake passage connected to the corresponding cylinder via the second intake valve. A second throttle valve is provided for each second intake passage and opens when the load of the engine is increased beyond a predetermined level. A blind common connecting passage is provided, which has a plurality of branch passages each being open to the corresponding second intake passage located downstream of the corresponding second throttle valve.

Abstract: 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.

Abstract: Adjustments to the amount of valve lift in an engine are readily made by corresponding adjustments to the location at which a cam actuated push rod contacts the push rod side of the valve actuating rocker arm. The invention provides an accurate and rapid means for adjusting the push rod contact position by slotting the push rod side of the rocker arm and fitting a square adjustment plate against a fixed index on top and bottom surfaces of the push rod side. Each adjustment plate has a hole for accommodating a tappet bolt and the holes are off-center located so that there is a different space between the hole and each of the square plates' four edges that may be rotated to a position against the fixed index to provide any one of four separate rocker arm ratios and therefore amounts of valve lift.

Abstract: A flow control valve assembly is connected to the cylinder head of a gas engine for providing an intermittent flow of gaseous fuel in timed relationship to the combustion chamber thereof. A valve cage is removably affixed to the cylinder head, and removably receives a valve cartridge in a telescoping manner therewithin. The valve cartridge cooperates with the valve cage in a manner whereby gaseous fuel flows into the cage, through ports formed in the cartridge, and from the interior of the cartridge into the combustion chamber of the gas engine. The valve cartridge includes a main outer housing which is easily separable into two members. A special seal assembly is received in captured relationship between a valve stem and the two separable members. The unique arrangement of the various components of the cartridge enables the device to be overhauled in a simple and straight forward manner.

Abstract: An improved variable stroke internal combustion engine (10) is disclosed. The power stroke and exhaust stroke of the engine are relatively longer than the intake stroke and compression stroke for increased power output from the engine (10). A connecting rod (40) is pivotally connected to the piston (16) and a trunnion assembly (28). The trunnion assembly is rotatably mounted to a journal (24) on the crankshaft (20). A control shaft (46) is rotatably mounted within the engine and connected to the crankshaft (20) so that the control shaft rotates at one-half the angular velocity of the crankshaft. A control link (52) is rotatably mounted on a journal (50) of the control shaft (46) with its opposite end being pivotally connected to the trunnion assembly (28).

Abstract: The two-cycle internal combustion engine includes an engine block having a cylindrical wall defining a cylinder having a head end, a piston mounted for reciprocative movement in the cylinder, and a passage in the engine block, such as an exhaust passage, a transfer passage, or a crankcase fuel intake passage, terminating at the cylinder wall in a port, such as an exhaust port, a transfer port or a piston-controlled, crankcase fuel intake port, having upper and lower edges. A valve mounted in the passage for movement relative to the port is operable to selectively vary the effective distance of one of the port edges from the cylinder head end and thereby provide the capability of varying the timing of the port opening and/or closing as required to obtain optimum engine performance at different operating conditions.

Abstract: Several embodiments of induction systems for internal combustion engines which provide stratification with an open chamber thus eliminating the need for auxiliary chambers and obviating the need for employing fuel injection. In all embodiments, first and second intake passages communicate with the chamber and one of these intake passages delivers a substantially weaker mixture than the other. This weaker mixture is admitted during the initial intake stroke and a richer fuel/air mixture is admitted at the end of the intake stroke so as to insure the existence of a stoichiometric mixture at the spark plug at the time of firing.

Abstract: A valve operating system of an internal combustion engine comprises a rocker arm swingable relative to a rocker arm shaft, and having a first end portion co-operative with an operating cam and a second end portion co-operative with a valve stem. The rocker arm is formed at its central part with a bearing section at which the rocker arm is swingably supported on the rocker arm shaft. The bearing section abuttingly contacts and extends along the outer peripheral surface of the rocker arm shaft. Additionally, the valve operating system is so arranged that engine lubricating oil is supplied under pressure between the rocker arm bearing section and the rocker arm shaft, thereby rendering the valve clearance zero in order to reduce noise generation from the valve operating system.

Abstract: A valve of an internal combustion engine in which for purposes of increasing the strength within the area of the annular groove for the conical pieces retaining the spring plate for the valve springs, the corners of the annular groove are rounded-off with a relatively small radius which passes over into the cylindrical part of the annular groove by way of a larger radius; the upper portion of the valve stem is provided with an outer layer which is induction-hardened and which extends up to within the clamping area of the conical pieces.

Abstract: Disclosed herein is an outboard motor comprising a cylinder, a crankcase extending from the cylinder and including an upper portion having a bearing and a lower portion having a drainage outlet, a transfer passage extending between the cylinder and the crankcase, a drains return inlet in one of the cylinder and the transfer passage, a fuel supply system including an inlet manifold communicable with the cylinder and having a drains outlet and a carburetor communicating with the inlet manifold and having a drainage outlet, an overboard drain, and a valve and conduit system selectively operable for communicating the overboard drain with each of the manifold drains outlet, the crankcase drains outlet, and the carburetor drainage outlet, for communicating the crankcase bearing and the drains return inlet with the manifold drains outlet and the crankcase drains outlet, and for closing the carburetor drainage outlet.

Abstract: A reciprocating piston internal combustion engine equipped with a vibration-damping balancing shaft that is rotatably supported in a bearing housing which in turn is secured at the cylinder crankcase by means of a threaded connection; in order to support the rotational forces of the balancing shaft between bearing housing and cylinder housing without play, at least one of the bolts of the threaded connection includes a conically shaped neck that cooperates with a corresponding chamfering in the bearing housing.

Abstract: A machine has two cylinders with respective pistons slidably supported therein, and has two crankshafts carrying counterweights operatively coupled to the respective pistons. A balance shaft carrying a balance weight is associated with and extends parallel to each crankshaft. The cylinders, crankshafts and balance shafts are parallel to and arranged in mirror-image fashion on opposite sides of a plane of symmetry. The crankshafts rotate synchronously in opposite directions, and each balance shaft rotates in an opposite direction from and at twice the speed of the associated crankshaft. In one embodiment the machine is an internal combustion engine and fuel is supplied to the cylinders through an eddy chamber which communicates with both cylinders through respective ducts. Two machines of the above type, an internal combustion engine and a compressor, can be operationally coupled, each crankshaft and balance shaft of the engine directly driving a respective crankshaft or balance shaft of the compressor.

Abstract: An internal type, spring damper for use in an internal combustion engine or the like having a cylinder head with a poppet valve supported for movement between valve open and valve closed positions and with a coiled valve return spring loosely encircling the stem of the valve and operatively associated at one end with the valve and having its bottom end operatively in abutment with the cylinder head whereby to normally bias the poppet valve to the closed position, has at least its corresponding bottom end of reduced external diameter for a predetermined axial extent whereby to eliminate damper-to-spring contact for up to at least 11/2 coils of the valve spring at its bottom end.

Abstract: A bearing arrangement for the balance shafts for balancing second order inertia forces on an internal combustion engine, in which the balance shafts run parallel to the crankshaft on both longitudinal walls of the crankcase, and have the ends carrying the balance weights supported by means of journal bearings within the crankcase and having driven ends supported by means of roller bearings outside the crankcase in the region of a crankcase end wall.

Abstract: An improved engine construction is disclosed having a valve train including valves and corresponding valve stems for controlling the intake and exhaust ports, cams for imparting reciprocating motion to the valves by way of the valve train, and a valve spring for biasing each valve toward its closed position and the valve train into tracking relation with the cam. The only element of the valve train coupling a cam to a stem is a cam follower with a depression for receiving the corresponding stem end and a cam engaging surface opposite the depression with the cam follower being held captive intermediate the stem and cam solely by the spring biasing of the stem toward the cam and the engagement of the stem end and the depression. Another feature of the engine resides in the engine block casting which includes an exhaust gas passageway extending from an engine cylinder and including near the end thereof remote from the cylinder an enlarged cavity which defines at least a part of a muffler shell.