Abstract: A liquid-cooled engine cylinder block wherein a plurality of cylinder walls forming cylindrical cylinders are arranged in series. The adjacent cylinder walls are joined together, and the outer circumference of these cylinder walls is covered by a water jacket wall. A passage for cooling liquid is formed between the water jacket wall and the cylinder walls in a direction perpendicular to the axes of cylinders. A guide rib is provided in the passage adjacent to the outer circumference of the cylinder walls so as to vertically divide the flow of cooling liquid. The guide rib comprises two guide members, one of which is inclined in an upward direction and the other inclined in a downward direction from their respective upstream ends. The cooling liquid in the passage is separated into upper and lower flows by the guide rib, and these flows combine a hollow area of the cylinder walls at the side of the cylinder joining member at the downstream of the guide rib.

Abstract: A main rocker arm which is pivotally mounted on a rocker shaft has one or more sub-rocker arms pivotally mounted thereon. The main rocker arm is arranged to synchronously open and close two poppet valves. Each of the sub-rocker arms can be selectively locked to the main one by way of hydraulically operated plunger arrangements. The main rocker arm is provided with a roller type cam follower which follows a low speed cam. The sub-rocker arms are provided with followers which engage high or very high speed cams. Lost motion springs which maintain the sub-rocker arms in contact with the cams are mounted on the main rocker arm.

Abstract: A schedule which is logged in terms of engine speed and which is divided into a number of engine operational zones, is used to determine the amount of axial displacement should be induced in a cam shaft on which a specially shaped cam is mounted. The cam has a first section which configured to simultaneously induce a change in valve lift and the valve closure timing, and a second section which maintains the valve closure timing at essentially a fixed value and induces a further increase in valve lift.

Abstract: In a valve train for an I.C. engine, a cam shaft has cams formed with compound curvatures which allow the valve timing to be altered while the engine is operating, to suit the engine driving conditions by shifting the cam shaft along its axis. To reduce the force necessary to shift the cam shaft along its axis the valve closure springs are replaced by closure cams. In some embodiments pivoting arrangements comprising a pair of ball and socket joints are provided to eliminate lateral sway of the rocker arms allowing precise adjustment of the valve timing when the cam shaft is shifted along its axis. In other embodiments the rocker arms are journalled on a rocker shaft provided with stops for preventing lateral sway. In some embodiments the closure rocker arms have cupped ends in which either the valve stem retainer or the valve stem seal is received.

Abstract: A rocker arm is pivotally mounted on a rocker shaft. A first cam follower such as a roller is provided on the rocker arm and arranged to cooperate with a low speed cam. A second cam follower is reciprocally mounted on the rocker arm and arranged to cooperate with a high speed cam. A locking arrangement for selective locking the second cam follower in place comprises three plungers which are each reciprocatively received in their own bore. One of the bores is formed in the second cam follower while the other two are formed in the rocker arm. When hydraulic pressure is applied to one end of one of the plungers and the high and low speed cam followers are in engagement with the base circles of the respective high and low speed cams, the plungers are axialy displaced against a return spring in a manner two project into an adjacent bore and induce interlocking.

Abstract: A variable valve timing type rocker arm arrangement is arranged so that, in the absence of sufficient hydraulic pressure to operate the interlocking mechanisms which switch the valve lift control from one cam follower to another, it defaults to a cam follower suited for low speed engine operation rather than one which is adapted to maximize fuel economy. During engine starts (when oil pump output is inherently low) the initial low speed cam follower defaulting improves aspiration and reduces the tendency for incomplete combustion to induce the formation of smoldering deposits on the spark plug electrodes. In the event of an actual hydraulic system malfunction, the defaulting enable the engine to produce enough torque to render the vehicle drivable.

Abstract: A cylinder head of a DOHC internal combustion engine has intake and exhaust ports of a siamese shape. A pivot for a rocker arm of the end pivot type is installed in a pivot installation hole which is formed at a nearer point from each cylinder than the branched point of each of the intake and exhaust ports. With this arrangement, since the pivot installation hole can have a sufficient depth without deforming the shape of the intake port, each swinging end of the rocker arm for intake valves and that for the exhaust valves can be disposed opposite to each other. Therefore, the engine is improved with respect to its performances and size.

Abstract: Main and sub-rocker arms mounted on a common shaft and pivotally supported on a cylinder head by a pivot formed at the end of an adjust screw which is provided at one of the main rocker arm. The main and sub-rocker arms are motivated by cams suited for low engine speed and high engine speed operation respectively. A hydraulically operated interlocking device which selectively locks the main and sub-rocker arms together, is controlled by a supply of hydraulic fluid by way of a passage structure formed in the adjust screw and a pivot seat in which the pivot is received.

Abstract: The first of a pair scissor like rocker arms is pivotally mounted at one end either by way of an adjust screw or a hydraulic lash adjuster and arangement to engage the top of a valve stem at the other. A cam follower which is located between the first and second ends engages a lift cam. The second of the rocker arms is pivotally mounted on the first one and has a closure cam follower at one end and engages the lower face of a retainer which secured to the top of the valve stem by way of a ring type collet. The shaft on which the second rocker arm is pivotally mounted can be provided with eccentric portions which enable the second rocker arm valve clearances to be adjusted separately from the adjustment of the first rocker arm clearance. The arrangement can be adapted to lift and close two valves.

Abstract: A first rocker arm is used to induce valve lift while a second one used to move the valve back to closed position. The rocker arms are arranged to engage the valve top or retainer surfaces at locations offset from the axis of the valve and to induce the valve to rotate during the lift and closing operations. Springs, hydraulic lifters or double adjust screw type arrangements are used to control clearances.

Abstract: A valve operating system for an overhead camshaft type automotive internal combustion engine. The valve operating system is comprised of a swing arm swingable upon rotation of a camshaft located over the swing arm. The swinging motion of the swing arm causes the reciprocal motion of intake or exhaust valve which is connected to one end section of the swing arm. The other end section of the swing arm is pivotally supported by the plunger of a hydraulic lifter in such a manner that the swing arm end section is in fitting contact with the tip end section of the hydraulic lifter plunger. A clearance is formed between the swing arm end section and the plunger tip end section and filled with lubricating oil which is supplied through an oil supply passage formed in the plunger of the hydraulic lifter, thereby accomplishing sufficient and efficient lubrication at the contacting and sliding surface between the swing arm and the hydraulic lifter plunger.

Abstract: In order to prevent the electrodes of the spark plug from becoming wetted with droplets of liquid fuel during low temperature and/or idling operation of the engine in a manner which deteriorates engine stability, the branches of a bifurcate intake passage which cooperates with a dual inlet valve arrangement are arranged to guide the unvaporized liquid fuel into the combustion chamber in a manner which obivates contact with the plug. In some embodiments a passage which is adapted to produce a swirl in the combustion chamber is arranged so that the fuel which passes therethrough (usually in the form of a film on the walls of branches) and which has a relatively large inertia as compared with the gaseous charge, enters the combustion chamber with a velocity which carries it along a flight path non-intersective with the plug electrodes.

Abstract: In order to reduce the mass of a rocker arm and simultaneously simplify the adjustment of the valve clearances the rocker arm is pivotally mounted on a universal joint so that it may tilt and establish a three point contact between the universal joint and the tops of the two valve stems. By incorporating a hydraulic lifter in the universal joint arrangement constant lash free automatic zero clearance adjustment is rendered possible. Utilizing a roller as a cam follower permits a reduction in valve train friction loss. To prevent the rocker arm from meandering retaining flanges are provided on the rocker arm which envelope the tops of the valve stems.

Abstract: A two-fingered cam follower adapted to operate two valves in unison has sliding faces which are arranged in parallel with the plane in which the cam follower swings being driven by a cam. The cam follower is pivotally mounted on a hydraulic lash adjuster which is in turn mounted on a cylinder head. The cylinder head is provided with a pair of guide arms which are arranged so as to interpose therebetween the cam follower. The guide arms have on the inboard sides thereof guiding faces respectively matched with the sliding faces of the cam follower in such a manner that a clearance is provided between the matched sliding and guiding faces. By setting the clearance in such a manner as to satisfy a certain relation, the sliding and guiding faces can be held out of contact with each other during normal operating condition of the engine.

Abstract: An engine valve operating system for an internal combustion engine comprises a rocker arm for transferring valve actuating effect from a driving cam to an engine valve such as an intake or exhaust valve. An elongate lever or fulcrum member is pivoted at its one end section and disposed in fulcrum contact with the side of the rocker arm opposite to the driving cam. Additionally, a hydraulic actuator is provided to control the pivotal location of the lever and therefore has a movable end section which is in contact with the other end section of the lever and movable in accordance with an engine operating condition, thereby greatly improving control response of the lever while rendering unnecessary a large capacity and sized actuator.

Abstract: In a variable venturi carburetor in which the metering jet portion of fuel changes automatically according to the amount of intake air required to keep the mixture at a constant air-to-fuel ratio at all times, two series-arranged nozzles and an auxiliary fuel passage communicating with the downstream side of the venturi and with the space formed between the two nozzles additionally formed at the fixed venturi portion in such a way that the auxiliary fuel passage can be opened or closed according to engine operating conditions. Therefore, when the auxiliary fuel passage is opened, since fuel is introduced into the venturi through only a single nozzle, a rich mixture is obtained; when the auxiliary fuel passage is closed, since fuel is introduced through two nozzles, a lean mixture is obtained.

Abstract: In a prior-art variable venturi carburetor in which the cross-sectional area of venturi is automatically varied according to the amount of intake air to keep the flow rate of intake air or the vacuum generated at the venturi at a constant level, since the cross section of venturi changes rectangularly, fuel is concentratedly jetted only near the middle portion of the venturi, so that fuel is not uniformly mixed with air passing through the venturi. To overcome these drawbacks, a wall having a reverse trapezoidal recess is provided near the nozzle and further a pair of triangular slots or cutouts are formed near the lower end surface of the suction piston obliquely and symmetrically so as to slidably engage with the wall, with the result that the cross section of the venturi changes trapezoidally and therefore a stable mixture is obtained even when the engine is running at a low speed or being idled.

Abstract: A piston has formed in the top thereof a part-spherical depression which forms part of a combustion chamber. The depression is so formed as to permit the flame front during the initial stage of combustion to reach the surface of the depression substantially at the same time, giving better conditions for efficient combustion and short combustion duration.

Abstract: For use in a swirl-producing recombustion chamber of a Diesel engine, a glow plug comprises a shell which can be screwed into an engine block so as not to protrude into the precombustion chamber and a cylindrically shaped heating head attached to a plunger which is received in the shell and can be electromagnetically or hydraulically moved relative to the fixed shell. The heating head can be protruded from the shell so as to extend into a central region of the precombustion chamber when preheating of air is necessary but, at other times, can be retracted almost entirely into the shell so as not to obstruct violent swirling of air in the precombustion chamber.