Abstract: A return spring is constituted of a torsion spring, a spring part is held at a position different from that of a shaft part of a flyweight, and a free end portion of the return spring is hooked to a slide unit of the flyweight. The position of transmission of an urging force to be transmitted from the return spring to the flyweight is different between an angle-closing side and an extending and opening side. By tuning the shape of the slide unit, the position of protrusion of a spring fixing pivot, or the like, the distance from the shaft part to a contact point of the free end portion when the flyweight is located at the angle-closing position is set to be larger than the distance from the shaft part to the contact point of the free end portion when the flyweight is located at the extending and opening position.

Abstract: A four stroke engine has a camshaft driven by a crankshaft. A decompression member is disposed on the camshaft. The decompression member is movable between a decompression position and a non-decompression position. A portion of the decompression member generally places the valve at an open position when the decompression member is placed at the decompression position and releases the valve from the open position when the decompression member is placed at the non-decompression position. A regulating member is disposed on the camshaft. The regulating member regulates the decompression member to prevent movement of decompression member from the decompression position when the regulating member is placed at a first position. The regulating member releases the decompression member from the decompression position when the regulating member is placed at a second position. A bias member is arranged to urge the regulating member toward the first position.

Abstract: A valve operating system includes: a decompression cam member that is provided on a camshaft, and moves between an operative position C where an exhaust tappet is operated in a valve opening direction in a compression stroke and an inoperative position D where the exhaust tappet is released; an exhaust gas recirculation cam member that is provided on the camshaft, and moves between an inoperative position F where the exhaust tappet is released and an operative position G where the exhaust tappet is operated in a valve opening direction in an intake stroke of the engine; and a common centrifugal mechanism that is driven by the camshaft to operate the decompression cam member to the operative position C in a starting rotation region of the engine and to the inoperative position D after the starting, and operate the exhaust gas recirculation cam member to the inoperative position F in a low speed operation region of the engine and to the operative position G in a high-speed operation region.

Abstract: A start control apparatus of an internal combustion engine comprises an ignition device for igniting an air-fuel mixture in a combustion chamber of the internal combustion engine, a start demanding device for demanding a start of the internal combustion engine, a starting device for starting the internal combustion engine, a determining device for determining a possibility of a self-ignition of the internal combustion engine at a time when a start demand is issued from the start demanding device, and a start procedure control device for igniting the air-fuel mixture in the combustion chamber by the ignition device after the start demand from the start demanding device in the case where the determining device determines that the possibility of the self-ignition of the internal combustion engine is higher than a predetermined level, thereafter starting the internal combustion engine by the starting device.

Abstract: A spark plug adapter allows for installation into the cylinder head of an internal combustion engine of an improved high-performance spark plug of configuration considerably different from that which the cylinder head was manufactured to accept. This is accomplished without disassembly of the engine or machine work on the cylinder head, and provides for a considerably improved smoothness of operation of and power production from the engine. An alternative embodiment of the inventive spark plug adapter provides for a compression release valve to communication with the combustion chamber of the engine, considerably easing starting for the engine, and still without disassembly of the engine or machine work on the cylinder head. A third embodiment of the inventive spark plug adapter provides for improved sealing of combustion gases.

Abstract: An electromechanical compression release valve for compressors, engines with rotary or reciprocating mechanisms and external combustion engines, such as, a Stirling cycle engine, reduces the engine starting power by reducing the compression pressure in the cylinder head space area. The valve reduces the compression pressure by passing the working fluid from the cylinder head space to another compartment. The valve comprises a housing, a valve member, a valve-driving member, a valve position sensor, and a ratchet pawl. In the open position, and while starting the engine, the inlet of the rotatable valve member is aligned with the opening in a chamber connected to the engine work space, thus, the working fluid passes through the valve member into the crankcase. After the engine starts, the valve position sensor directs the valve-driving member to rotate the valve member to the closed position. When closed, the engine working fluid can now achieve the operating compression pressures.

Abstract: A starting apparatus includes a drive motor and a reduction gear having a planetary gear for starting an engine by the drive motor via the reduction gear. An internal gear of the reduction gear includes a locking projection projecting in an axial direction. A rotation restricting member is formed with a guide groove in which the locking projection is loosely received and guided in a circumferential direction. A shock absorbing member is held in the guide groove in a state of being elastically in close contact with the locking projection in the circumferential direction. Thus, shock load to the internal gear is alleviated from the start.

Abstract: An engine is cranked by a motor generator at a start time of the engine. An engine ECU opens an intake valve or an exhaust valve during a compression stroke using a valve control mechanism during a period from when cranking is started until when a predetermined crank angle position (detected by a crank angle sensor) is reached, thereby reducing a compression workload.

Abstract: A decompressing mechanism (D) for an internal combustion engine (E) is incorporated into a camshaft (15) provided with a bore (54) extending in the direction of the arrow (A) along the axis (L1) of rotation of the camshaft (15). The decompressing mechanism (D) includes a decompression member (80) formed by metal injection and integrally having a flyweight (81), a decompression cam (82) for exerting a valve-opening force through an exhaust rocker arm (48) on an exhaust valve, and an arm (83) connecting the flyweight (81) and the decompression cam (82). The flyweight (81) is supported for swing motion by a pin (71) on the camshaft (15). The axis (L2) of swing motion of the flyweight (81) is included in a plane (P4) substantially perpendicular to the axis (L1) of rotation, and does not intersect the axis (L1) of rotation and the bore (54) of the camshaft (15). The fully expanded decompression member (80) revolves in a cylindrical space of a small diameter around the camshaft (15).

Abstract: A method is provided for starting an internal combustion engine having a plurality of cylinders, each cylinder having at least one inlet valve and one exhaust valve. In accordance with one embodiment the method includes the steps of opening an inlet valve of any cylinder that would otherwise undergo a wasted power stroke and opening an exhaust valve of any cylinder that would otherwise undergo a wasted compression stroke.

Abstract: A starting device for an internal combustion engine is capable of increasing starting torque as well as supplying air to a cylinder that is on the expansion stroke without separately providing a means for supplying high-pressure air. Communication control valves control the states of communication between cylinders of the engine. A crank angle detector detects the crank angle of a crankshaft of the engine. A compression/expansion identification part identifies the compression stroke or the expansion stroke of each cylinder. Fuel is injected into a cylinder on the expansion stroke and ignited therein, and the expansion stroke cylinder is placed in communication with a cylinder on the exhaust stroke by a communication state control part for a prescribed time after the ignition thereof, after which the expansion stroke cylinder is further placed in communication with a cylinder on the compression stroke for a prescribed time.

Abstract: An automatic compression release mechanism for in an internal combustion engine, includes a camshaft assembly including a cam gear, a cam lobe with a notch positioned along a first side of the gear, a tube passing through the cam gear and aligned with the notch, and a support on a second side of the cam gear. An actuator assembly includes a contoured shaft that extends through the tube and resides in the notch. The actuator assembly is rotatable between two operating orientations and a step formed in the surface of the notch prevents the actuator from becoming disabled during engine shut down.

Abstract: In a multi-cylinder combustion engine with a variable compression ratio a start of the combustion engine is performed with a compression ratio which is reduced relative to compression ratios in normal operation of the combustion engine.

Abstract: A starting device for an internal combustion engine is capable of increasing starting torque as well as supplying air to a cylinder that is on the expansion stroke without separately providing a means for supplying high-pressure air. Communication control valves control the states of communication between cylinders of the engine. A crank angle detector detects the crank angle of a crankshaft of the engine. A compression/expansion identification part identifies the compression stroke or the expansion stroke of each cylinder. Fuel is injected into a cylinder on the expansion stroke and ignited therein, and the expansion stroke cylinder is placed in communication with a cylinder on the exhaust stroke by a communication state control part for a prescribed time after the ignition thereof, after which the expansion stroke cylinder is further placed in communication with a cylinder on the compression stroke for a prescribed time.

Abstract: A decompression device is provided for an internal combustion engine having a cylinder head provided with a pair of left and right camshaft bearings sandwiching intake valves and exhaust valves with a structure that is both simple and small. A camshaft is provided having cam projections for at least a pair of intake cams between camshaft side bearings corresponding to the pair of left and right bearings, and a decompression member with a decompression cam with a centrifugal weight arranged at a camshaft end passing through the bearing close to the camshaft end so that a tip thereof is arranged in the vicinity of the cam projections, with the decompression member comprising the centrifugal weight, the decompression cam, and a rotatable shaft coupling the centrifugal weight and the decompression cam in an integral manner.

Abstract: A decompression device of an internal combustion engine which is arranged compactly with reduced number of parts is provided. Typically, the device comprises a push-up rod which is disposed on a circumference of a cam shaft of the engine, within a range in the circumferential direction corresponding to a compression stage of the engine, and which protrudes outwardly in the radial direction of the cam shaft with respect to a base face of an exhaust-side cam face. The push-up rod is supported movably in the cam shaft direction between a decompression operating position, at which the push-up rod is inserted into a width-wise range of a bottom face of an exhaust-side tappet and a decompression non-operating position, at which the push-up rod is retreated from the width-wise range of the bottom face.

Abstract: A decompressor for use in an internal combustion engine is disclosed The decompressor is at least partially located within the venting passageway in response to pressure in the combustion chamber for selectively opening the venting passageway such that combustion gas located within the chamber is vented to the induction passageway. The decompressor opens the venting passageway when the engine is off and during an engine start up operation. The decompressor includes an expansible cavity operatively connected to the combustion chamber.

Abstract: This invention relates to a cam mechanism with a decompression device formed by integrating a centrifugal weight and a decompression cam lobe. The decompression device is formed by preparing a cylindrical shaft having a decompression cam lobe at one end of the shaft and a centrifugal weight at the other end. The device is constructed to be disposed on a camshaft by inserting the decompression cam lobe into a grove portion of a second cam, and pivotally supporting the shaft receiving hole on the camshaft.

Abstract: An internal combustion engine having a centrifugally-responsive vacuum release mechanism that relieves a vacuum within a combustion chamber during the expansion stroke of an engine at engine starting speeds. The vacuum release mechanism is disposed adjacent the cam and engages a cam follower at engine starting speeds to unseat an engine valve while an engine piston is moving toward a crankcase and away from the combustion chamber. When the engine rotation speed reaches a desired kick-out speed, the centrifugal force transitions the vacuum release mechanism from an engaged position to a disengaged position. The vacuum release mechanism engages the cam follower to separate the cam follower from the cam when the vacuum release mechanism is in the engaged position. When the vacuum release mechanism is in the disengaged position during normal operating speeds, the cam follower is permitted to contact the cam throughout the entire rotation of the cam.

Abstract: A multicylinder internal combustion engine has a valve chamber containing a valve train for opening and closing intake valves and exhaust valves, and decompression mechanisms. First, second and third cylinders are arranged in a row parallel to an axial direction parallel to the axis of a camshaft. An exhaust cam for opening and closing the exhaust valve, which is opened and closed by the decompression mechanism, for the second cylinder is not coincident with respect to the axial direction with an abutment end of the exhaust valve with which a rocker arm driven by the exhaust cam comes into contact, and is coincident with respect to the axial direction with the decompression mechanism. Thus, a space for placing the decompression mechanism is secured while suppressing increase in the length of the camshaft and in the longitudinal size of the valve chamber. Consequently, the internal combustion engine can be formed in compact construction.

Abstract: A decompressing mechanism included in an internal combustion engine has a flyweight supported for swinging motion by a pin on the camshaft of the internal combustion engine, a decompression cam and an arm connecting the flyweight and the decompression cam and having the shape of a plate. The flyweight has a weight body and projections projecting from the weight body and engaged with the pin. The weight body is a block of a width along the axis of swinging motion and a thickness, along a radial direction, which are greater than the thickness, along the axis, of swinging motion of the arm. The weight body overlaps the camshaft as viewed from a direction perpendicular to a reference plane. The decompressing mechanism is small, lightweight and is capable of concentrating most of its mass on the flyweight.

Abstract: A decompression device for an engine reduces pressure in the engine's combustion chamber thereby reducing the amount of force required to start the engine. The decompression device incorporates a decompression lever that cooperates with a cam surface to hold engine valves open longer than normal while the engine is being started. The decompression lever has a weight section and a lifter section. The lifter section is located near a pivot location on the decompression lever and is generally the same thickness as the weight section. The lifter section protrudes beyond the cam gear to hold the engine valves open longer while starting the engine. After the engine has started, the decompression lever rotates into a retracted position to allow the engine valves to open and close normally.

Abstract: The invention pertains to an automatic decompression device for valve-controlled internal combustion engines, having at least one camshaft for the actuation of gas shuttle valves and a decompression lever, which acts in cooperation with at least one gas shuttle valve and which is attached in a pivoting fashion on the camshaft on an axis of rotation, and which can be moved against a spring force from a first switch position into a second switch position as a result of the centrifugal forces acting on it during the revolution of the camshaft. It is suggested that the decompression lever be designed as a bow element the two ends of which are attached to the camshaft. The decompression arrangement is distinguished by a simple design, and is especially well-suited for small engines due to its lightweight construction.

Abstract: A decompression device is provided for an internal combustion engine having a cylinder head provided with a pair of left and right camshaft bearings sandwiching intake valves and exhaust valves with a structure that is both simple and small. A camshaft is provided having cam projections for at least a pair of intake cams between camshaft side bearings corresponding to the pair of left and right bearings, and a decompression member with a decompression cam with a centrifugal weight arranged at a camshaft end passing through the bearing close to the camshaft end so that a tip thereof is arranged in the vicinity of the cam projections, with the decompression member comprising the centrifugal weight, the decompression cam, and a rotatable shaft coupling the centrifugal weight and the decompression cam in an integral manner.

Abstract: An internal combustion engine is provided with a decompressing mechanism including: a pin supported so as to be turnable on a camshaft; a flyweight supported for turning relative to the camshaft by the pin on the camshaft; and a decompression cam capable of operating together with the flyweight to apply valve opening force to an engine valve. The pin is inserted in holes formed in the flyweight so as to be turnable. A spring washer restrains the pin and the flyweight from movement relative to each other, so that generation of rattling noise due to collision between the pin and the flyweight can be prevented or controlled.

Abstract: This invention relates to a cam mechanism with a decompression device formed by integrating a centrifugal weight and a decompression cam lobe. The decompression device is formed by preparing a cylindrical shaft having a decompression cam lobe at one end of the shaft and a centrifugal weight at the other end. The device is constructed to be disposed on a camshaft by inserting the decompression cam lobe into a grove portion of a second cam, and pivotally supporting the shaft receiving hole on the camshaft.

Abstract: An internal combustion engine has a valve train and decompression mechanisms disposed in a valve chamber, and a fuel pump attached to a cylinder head. A pump cam for driving the actuating rod of a fuel pump through a swing arm, and a decompression mechanism opposite an end journal relative to the pump cam with respect to an axial direction parallel to the axis of the camshaft are formed on the camshaft in the valve chamber. One of the decompression mechanisms is disposed between the pump cam and an exhaust cam. The swing arm has a contact tip in contact with the pump, cam and a pushing tip in contact with the actuating rod at a position nearer to the exhaust cam than the contact part with respect to the axial direction. The pump cam comes into contact with an end bearing supporting the camshaft to restrain the camshaft from axial movement.

Abstract: A compression release mechanism for small internal combustion engines, including a compression release member having an auxiliary cam and a weight section. The compression release member is supported for rotation on an annular bearing surface which is in eccentric relation to the longitudinal axis of the engine camshaft. At engine cranking speeds, the compression release member rotates with the camshaft, and the auxiliary cam projects beyond the base circle of a cam lobe on the camshaft to periodically engage a valve to vent pressure from the engine combustion chamber during the compression stroke of the piston to aid in engine cranking. After the engine starts, rapid rotation of the camshaft causes the compression release member to rotate under the inertial load of the weight section thereof to a position in which the auxiliary cam is retracted within the base circle of the cam lobe such that combustion may proceed in a conventional manner.

Abstract: A decompression system for a four-cycle engine includes a decompression shaft positioned within a camshaft. The decompression shaft interacts with decompression pins positioned within pin holes formed in the camshaft. In some embodiments, the decompression shaft is formed from a first longitudinal portion and a second longitudinal portion. In other embodiments, the decompression shaft is supported at least in part by a middle portion of a bore that extends through the camshaft.

Abstract: An internal combustion engine having a centrifugally-responsive vacuum release mechanism that relieves a vacuum within a combustion chamber during the expansion stroke of an engine at engine starting speeds. The vacuum release mechanism is disposed adjacent the cam and engages a cam follower at engine starting speeds to unseat an engine valve while an engine piston is moving toward a crankcase and away from the combustion chamber. When the engine rotation speed reaches a desired kick-out speed, the centrifugal force transitions the vacuum release mechanism from an engaged position to a disengaged position. The vacuum release mechanism engages the cam follower to separate the cam follower from the cam when the vacuum release mechanism is in the engaged position. When the vacuum release mechanism is in the disengaged position during normal operating speeds, the cam follower is permitted to contact the cam throughout the entire rotation of the cam.

Abstract: A system and method for controlling a variable displacement engine during cranking and starting period include a hybrid operating mode to allow intake/exhaust valve operation while preventing fuel delivery or spark, or both, to at least one subsequently deactivated cylinder or bank of cylinders during the cranking and starting period. The system and method provide advantages to starting the engine relative to either a variable displacement mode or a full activation mode.

Abstract: A compression release mechanism for small internal combustion engines, including a compression release member having an auxiliary cam and a weight section. The compression release member is supported for rotation on an annular bearing surface which is in eccentric relation to the longitudinal axis of the engine camshaft. At engine cranking speeds, the compression release member rotates with the camshaft, and the auxiliary cam projects beyond the base circle of a cam lobe on the camshaft to periodically engage a valve to vent pressure from the engine combustion chamber during the compression stroke of the piston to aid in engine cranking. After the engine starts, rapid rotation of the camshaft causes the compression release member to rotate under the inertial load of the weight section thereof to a position in which the auxiliary cam is retracted within the base circle of the cam lobe such that combustion may proceed in a conventional manner.

Abstract: An internal combustion engine has a valve train (V) and decompression mechanisms (D1, D2 and D3) disposed in a valve chamber (30), and a fuel pump (74) attached to a cylinder head (4). A pump cam (68) for driving the actuating rod (78) of a fuel pump (74) through a swing arm 79, and a decompression mechanism (D3) opposite an end journal (63) relative to the pump cam (68) with respect to an axial direction (A1) parallel to the axis of the camshaft (31) are formed on the camshaft 31 in the valve chamber (30). The decompression mechanism (D3) is disposed between the pump cam (68) and an exhaust cam (52). The swing arm (79) has a contact tip (79b) in contact with the pump cam (68), and a pushing tip (79a) in contact with the actuating rod (78) at a position nearer to the exhaust cam (52) than the contact part (79b) with respect to the axial direction (A1). The pump cam (68) comes into contact with an end bearing (66) supporting the camshaft (31) to restrain the camshaft (31) from axial movement.

Abstract: A multicylinder internal combustion engine has a valve chamber (30) containing a valve train (V) for opening and closing intake valves (43) and exhaust valves (44), and decompression mechanisms (D1 to D3). First, second and third cylinders (C1, C2 and C3) are arranged in a row parallel to an axial direction (A1) parallel to the axis of a camshaft (31). An exhaust cam (50) for opening and closing the exhaust valve, which is opened and closed by the decompression mechanism (D2), for the second cylinder (C2) is not coincident with respect to the axial direction (A1) with an abutment end (44A) of the exhaust valve with which a rocker arm (58) driven by the exhaust cam (50) comes into contact, and is coincident with respect to the axial direction (A1) with the decompression mechanism (D2). Thus, a space for placing the decompression mechanism (D2) is secured while suppressing increase in the length of the camshaft (31) and in the longitudinal size of the valve chamber (30).

Abstract: A valve timing control system includes a first device for changing a mounting angle between driving and driven rotators through relative rotation thereof and including first and second rotating mechanisms coupled to each other in series, and a second device for locking the first device at a mounting-angle position which is suitable for engine start and is set between a most-lagged-angle position and a most-advanced-angle position. The second device includes a first lock mechanism for locking the first rotating mechanism at one of the most-lagged-angle position and the most-advanced-angle position and a second lock mechanism for locking the second rotating mechanism at another position. The first and second rotating mechanisms are locked by the first and second lock mechanisms at opposite positions to maintain the mounting angle at the mounting-angle position suitable for engine start.

Abstract: A decompressor for use in an internal combustion engine is disclosed The decompressor is at least partially located within the venting passageway in response to pressure in the combustion chamber for selectively opening the venting passageway such that combustion gas located within the chamber is vented to the induction passageway. The decompressor opens the venting passageway when the engine is off and during an engine start up operation. The decompressor includes an expansible cavity operatively connected to the combustion chamber.

Abstract: An apparatus is described to separate oil from a gas in an internal combustion engine. The apparatus includes a rotatable member adapted to be rotatably driven by the internal combustion engine and a housing affixed to the rotatable member. At least one inlet hole is disposed through one of either the rotatable member or the housing, permitting oil-containing gas to pass therethrough. At least one outlet hole is disposed through one of either the housing or the rotatable member, permitting the gas to exit therefrom. At least one labrynthine passage extends between the at least one inlet and the at least one outlet so that, as the rotatable member and housing rotate, the oil-containing gas within the labrynthine passage is subjected to centrifugal forces. The forces cause at least some of the oil to be removed from the gas as the gas flows from the at least one inlet hole to the at least one outlet hole. A decompressor is also described.

Abstract: An automatic decompression device for an internal combustion engine includes a camshaft rotatable about an axis of rotation and having an end face, and a lever coupled to the end face and movable between a first position, wherein the lever is engageable with a valve actuating device to actuate a valve during rotation of the camshaft, and a second position, wherein the lever does not substantially move the valve actuating device. The lever is preferably pivotally coupled to the end face to pivot about a pivot axis that is substantially perpendicular to the axis of rotation of the camshaft. Further preferably, the automatic decompression device further includes a spring between the end face and the lever to bias the lever toward the first position. In a highly preferred embodiment, the end face of the camshaft includes a slot and the lever is at least partially retained within the slot.

Abstract: An internal combustion engine having a centrifugally-responsive vacuum release mechanism that relieves a vacuum within a combustion chamber during the expansion stroke of an engine at engine starting speeds. The vacuum release mechanism is disposed adjacent the cam and engages a cam follower at engine starting speeds to unseat an engine valve while an engine piston is moving toward a crankcase and away from the combustion chamber. When the engine rotation speed reaches a desired kick-out speed, the centrifugal force transitions the vacuum release mechanism from an engaged position to a disengaged position. The vacuum release mechanism engages the cam follower to separate the cam follower from the cam when the vacuum release mechanism is in the engaged position. When the vacuum release mechanism is in the disengaged position during normal operating speeds, the cam follower is permitted to contact the cam throughout the entire rotation of the cam.

Abstract: The invention pertains to an automatic decompression device for valve-controlled internal combustion engines, having at least one camshaft for the actuation of gas shuttle valves and a decompression lever, which acts in cooperation with at least one gas shuttle valve and which is attached in a pivoting fashion on the camshaft on an axis of rotation, and which can be moved against a spring force from a first switch position into a second switch position as a result of the centrifugal forces acting on it during the revolution of the camshaft. It is suggested that the decompression lever be designed as a bow element the two ends of which are attached to the camshaft. The decompression arrangement is distinguished by a simple design, and is especially well-suited for small engines due to its lightweight construction.

Abstract: An apparatus and method for starting an engine having a starter generator for providing a rotational force to a pulley in order to provide the necessary torque to start an engine. The starter generator also receives a rotational force to the pulley wherein the starter generator generates a current when the pulley receives the rotational force. A valve deactivation system reduces the compression in a cylinder of the engine, thereby reducing the torque required to perform a starting sequence of the engine, either permitting this apparatus to be applied to larger engines, lower ambient temperatures, or some combination thereof.

Abstract: In an internal combustion engine provided with a decompression mechanism, a decompression cam that is rotatable with respect to a camshaft between first and second stop positions has a cam profile so that an exhaust valve is opened at the first stop position and is closed at the second stop position. The decompression cam is rotated in the reverse direction to the first stop position by rotating a crankshaft in the reverse direction by an electric motor at startup (position P1). Only the crankshaft is then rotated in the reverse direction (position p3), and the decompression cam is rotated in the normal direction by rotating the crankshaft in the normal direction by the electric motor.

Abstract: In a decompression unit including a decompression arm, a decompression unit for internal combustion engine is provided in which the followability in the opening-and-closing operation of the air intake valve or the exhaust valve with respect to the cam at high-revolution speeds is satisfactory without increasing the equivalent inertia weight of the valve driving system, and for lowering the cost. A decompression unit includes a first decompression cam that takes the operating position when the number of revolutions of the engine is not more than the predetermined number of revolution during startup. A second decompression cam is provided that takes the operating position by manual operation. A decompression arm includes first and second abutting portions that abut against first and second decompression cams, respectively.

Abstract: A compression release device for a small internal combustion engine, including a flyweight operatively coupled to a cam member via a cam pivot shaft, wherein a lever arm associated with the flyweight is longer than a lever arm associated with the cam member, such that a relatively small component of pivotal movement of the flyweight is translated into a relatively large component of rotation of the cam member. At engine cranking speeds, a spring biases the flyweight to a first position, such that a cam surface of the cam member extends beyond the base circle of the exhaust cam lobe to partially open the exhaust valve and allow release of pressure within the combustion chamber of the engine. At engine running speeds, the flyweight is moved under centrifugal force to a second position, rotating the cam member to a corresponding second position in which the cam surface is disposed within the base circle of the exhaust cam lobe, such that combustion may occur in a conventional manner.

Abstract: An engine with an electromagnetic driving valve reduces a loss during a cranking operation to shorten a starting time, reduce an electric power consumption for a starter motor, and prevent an interference between a valve system and a piston. Intake and exhaust valves are sequentially excited and started such that, after starting the cranking operation by a starter motor, a first cranking rotating speed can be reached, and the valves can be all closed at a predetermined cranking angle. All intake and exhaust valves are closed and the cranking rotating speed reaches an ignition point by the supply of a fuel and the continuous operation of the engine can be performed at more than a second cranking rotating speed, and the intake and exhaust valves can be switching controlled in the normal cylinder process.

Abstract: An automatic compression release mechanism for implementation in an internal combustion engine, and a method of assembling such a mechanism, are disclosed. The mechanism includes a camshaft assembly including a cam gear, a cam lobe with a notch positioned along a first side of the gear, a tube passing through the gear and aligned with the notch, and a support on a second side of the gear. The mechanism additionally includes an arm including a weight and shaft coupled to one another, where an end of the shaft includes a recess, and where the shaft is rotatably positioned within the tube and the end of the shaft with the recess extends into the notch. The mechanism further includes a retaining member positioned onto the support so that the weight is positioned between the retaining member and the tube and retained with respect to the gear.

Abstract: An engine is cranked by a motor generator at a start time of the engine. An engine ECU opens an intake valve or an exhaust valve during a compression stroke using a valve control mechanism during a period from when cranking is started until when a predetermined crank angle position (detected by a crank angle sensor) is reached, thereby reducing a compression workload.

Abstract: A compression relief mechanism for a small four-cycle engine to facilitate cranking. The engine has a single cam actuating both the intake and exhaust valves. The cam has a primary cam surface and a boss extending from its side. The exhaust valve cam follower engages only the primary cam surface. The intake valve cam follower has a first cam follower surface engaging only the primary cam surface and a secondary cam engagement surface engaging only the boss to open the intake valve during a predetermined portion of the engine's compression cycle. The opening of the intake valve during the compression cycle provides compression relief facilitating cranking. The secondary cam follower surface may be provided on either the intake or exhaust cam follower to open either the intake or exhaust valve during the compression cycle to provide the desired compression relief during cranking.

Abstract: A decompression device for an engine reduces pressure in the engine's combustion chamber thereby reducing the amount of force required to start the engine. The decompression device incorporates a decompression lever that cooperates with a cam surface to hold engine valves open longer than normal while the engine is being started. The decompression lever has a weight section and a lifter section. The lifter section is located near a pivot location on the decompression lever and is generally the same thickness as the weight section. The lifter section protrudes beyond the cam gear to hold the engine valves open longer while starting the engine. After the engine has started, the decompression lever rotates into a retracted position to allow the engine valves to open and close normally.

Abstract: A control (30) embodies an operating strategy (50) to facilitate engine cranking and starting via control of timing of cylinder intake (18) and exhaust (24) valve opening using a variable valve actuation mechanism (26). Prior to fueling any cylinder (16), the engine (10) is cranked while the variable valve actuation mechanism causes pistons (32) to operate at an initial effective compression ratio for initial cranking that is less than an effective compression ratio for running when the engine is eventually fueled and runs under its own power. Thereafter, and still before fueling, they are caused to operate at an increased effective compression ratio, and still thereafter, a portion of their charges are drawn from the exhaust system (22). As the engine warms up, valve timing is adjusted.