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: 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: Each cylinder of a multi-valve engine is provided with a bifurcate induction port which has a partition wall; a fuel injector which injects fuel toward the partition wall so that fuel is distributed into the two branches which lead to the inlet valves; and a flow control valve is disposed upstream of the partition wall and formed with one or more apertures which when the valve is closed, direct a flow or flows of air which pass close to the partition wall, entrain the injected fuel and induce a turbulent mixing action which forms an ignitable cloud of air-fuel mixture in close proximity to the spark plug.

Abstract: Disclosed is a spark ignition timing control system for a split type multi-cylinder internal combustion engine which operates to advance the spark advance angle of a specific combustion chamber relative to other combustion chambers. The control system generally comprises a means for detecting a knocking condition and generating knocking signal so as to retard spark advance angle corresponding to knocking of engine and a means for detecting engine load condition and thereafter advancing the spark advance angle of the specific combustion chamber when the engine is driven at relatively high loads.

Abstract: A vibration sensor for an automotive vehicle having a piezoelectric element of diaphragm type for detecting mechanical vibrations from an internal combustion engine such as knocking frequency. The piezoelectric element is formed within a holder of plastic or the like and bonded thereto in a manner to accurately regulate the clamping pressure at the element periphery and regulate the vibration area thereof to accurately regulate the resonant frequency of the vibration sensor.

Abstract: A device for detecting engine knock is disclosed. The device comprises a bipolar vibration sensor secured to a spark ignition internal combustion engine and has first and second outputs for generating respectively signals representing individual ringing engine vibrations due to engine knock and signals representing the background engine vibrations due to engine operation, separately. A smoothing circuit is connected to the second output side of the vibration sensor for forming a means value of the background engine vibration signals. A comparator circuit has a first input terminal connected to the first output side of the vibration sensor and a second input terminal connected to the output side of the smoothing circuit for comparing the mean value of the outputs of the smoothing circuit with the peak value of the ringing engine vibration signals. A utilization circuit is connected to the output side of the comparator circuit for controlling the driving condition of the engine in an optimum manner.

Abstract: A knocking sensor having a thin vibrating plate (10) receiving sound produced from an engine. The vibrating plate is applied with a piezoelectric element (11) which delivers electric output in proportion to the vibration. The resonance frequency of the vibrating plate is made same as the knocking frequency. A resonant tube (20) for forming resonating cavity is attached in front of the vibrating plate. A sound collector (30) is provided in front of the vibrating plate. A duct (50) is arranged between the sound collector and the sensor to improve sensitivity and freedom of mounting of the sensor.

Abstract: A combustion chamber of an internal combustion engine has the form of a B-shaped chamber which consists of two spheroidal or spherical contiguous chambers which form an inwardly extending projection against which the air and fuel mixture impinges so as to be divided into two swirl flows which sweep residual burned gases of the previous cycle in the combustion chamber, thereby preventing knocking in the operation of the engine to improve the fuel consumption, driving performance and output of the engine.

Abstract: A method and system for controlling ignition spark timing of an internal combustion engine of the multiple plugs type, in which a plurality of spark plugs are energized at different timings with a predetermined phase in dependence on the flow of air-fuel mixture in a combustion chamber, whereby air-fuel mixture is ignited at timings optimum for rapid combustion.

Abstract: The air-fuel mixture in each combustion chamber of a dual spark plug ignition engine is ignited with two spark plugs during normal engine operation, but is ignited with only one of the two spark plugs during high power output engine operation. The spark timing in the ignition with one spark plug is advanced relative to that in the ignition with two spark plugs.

Abstract: A valve, the opening degree of which is decreased with rise in the intake manifold vacuum is located in an exhaust gas recirculation conduit at the downstream of another valve, the opening degree of which is increased with rise in the vacuum at a port opening to the carburetor in the neighborhood of the periphery of the throttle valve in its closed position.