Abstract: A method of boot strap starting a diesel having a plurality of cylinders comprises the steps of initiating cranking the diesel and responsive to cranking forcing exhaust valves for all cylinders open during compression strokes. Thereafter, responsive to the engine rotational speed signal exceeding a first threshold, an exhaust valve for one cylinder is allowed to open and close in synchronous with movement of a piston in the cylinder. Further responsive to engine rotational speed exceeding a second threshold higher than the first threshold, cranking is discontinued and the remaining exhaust valves are allowed to open and close in synchronous with movements of pistons in their respective cylinders.

Abstract: An internal combustion engine is provided with a decompressing mechanism (D) including: a pin (71) supported so as to be turnable on a camshaft (15); a flyweight(81) supported for turning relative to the camshaft (15) by the pin (71) on the camshaft (15); and a decompression cam (82) capable of operating together with the flyweight (81) to apply valve opening force to the engine valve(43). The pin (71) is inserted in holes (84) formed in the flyweight (81) so as to be turnable. A spring washer (72) restrains the pin (71)and the flyweight (81) from movement relative to each other, so that generation of rattling noise due to collision between the pin (71) and the flyweight (81) can be prevented or controlled.

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.

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

Abstract: The invention relates to a start method and a start arrangement for an internal combustion engine (10) of motor vehicles having a crankshaft (11) connected to an electric machine (14) for cranking the engine. Crankshaft position and rotation are detected by a start control apparatus (19) and evaluated for controlling each start operation of the engine. The crankshaft (11) is first brought by the electric machine (14) into a start position during a positioning phase for each start operation.

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 decompressing mechanism (D) included in an internal combustion engine has a flyweight (81) supported for swing motion by a pin (71) on the camshaft (15) of the internal combustion engine, a decompression cam (82) and an arm (83) connecting the flyweight (81) and the decompression cam (82) and having the shape of a plate. The flyweight (81) has a weight body (81c) and projections (81a, 81b) projecting from the weight body (81c) and engaged with a pin (71). The weight body (81c) is a block of a width along the axis (L2) of swing motion and a thickness (t2), along a radial direction, which are greater than the thickness (t1), along the axis (L2), of swing motion of the arm (83). The weight body (81c) overlaps the camshaft (15) as viewed from a direction perpendicular to a reference plane (P3). The decompressing means (D) is small, lightweight and is capable of concentrating most part of its mass on the flyweight (81).

Abstract: Apparatuses and methods for reducing hydrocarbons in two-stroke engine exhaust. When a piston is close to top dead center, a groove in the lower end region of the piston confronts an exhaust port and first scavenging ports, respectively, and exhaust gas from the exhaust port is directed to the first scavenging ports. During a scavenging stroke, the first scavenging ports open first to a combustion chamber and exhaust gas is introduced to the combustion chamber, and a second pair of scavenging ports then opens to the combustion chamber and introduces a fuel-containing gas to the combustion chamber. When crankcase pressure reaches 142 Pa or higher, a relief valve opens and maintains the maximum pressure at 142 kPa or lower. Thus, blending in the combustion chamber of the exhaust gas from the first scavenging ports and the fuel-containing gas from the second scavenging ports is suppressed, and short-circuiting of the fuel component to the exhaust port is suppressed.

Abstract: An apparatus for releasing excessive pressure from a cylinder of an internal combustion engine comprises a sealing element inserted into a passageway that extends from an internal surface of the cylinder through the engine block or cylinder head to end at a point of ambient air pressure. The sealing element is thermally responsive and will release to cause the passageway to form a vent passage between the cylinder and the ambient air upon the occurrence of any one of a number of conditions of excessive pressure and temperature in the cylinder.

Abstract: An internal combustion engine includes pressure relief devices that reduce pressure due to compression during startup, thereby decreasing the force needed to start the engine. A pressure relief valve mounts on top of the cylinder head and includes a duct to the combustion chamber leading to the valve and a second duct leading to the exhaust port so that gases in the combustion chamber may be vented through the exhaust system. A mechanical actuator having cables directed to each of the pressure relief valves for each of the cylinders manually actuates a first embodiment. A second embodiment includes a solenoid with wiring tied into a starter circuit that actuates the multiple valves from a single actuator.

Abstract: In an automatic decompression device of a small OHC-type engine, a decompression control mechanism A comprises a weight member 5 including a pivot portion 5A pivotably attached to a cam shaft 20 at a position apart from a center axis O20 of the cam shaft and having an outer periphery curved along an outer periphery of a cam sprocket 15 and a tip end portion that engages with an operating shaft 1, to swing around the pivot portion 5A outwardly by rotation of the cam shaft 20; and a bias member (coil spring 17) for biasing a portion of the weight member 5 that is apart from the pivot portion 5A toward the center axis of the cam shaft 20 in a swing area, wherein the tip end portion 5C of the weight member 5 that engages with the operating shaft is situated on an opposite side of the pivot portion 5A with respect to the center axis O20 of the cam shaft 20.

Abstract: A four-stroke internal combustion engine includes a cylinder block including a cylinder therein and having a piston reciprocally disposed within the cylinder. A piston is operably engaged with a crankshaft. At least one intake valve is reciprocally driven by a camshaft. At least one exhaust valve is reciprocally driven by the camshaft. A vacuum release mechanism includes an operating member reciprocally supported within the camshaft for translation along an axis. A centrifugally actuated flyweight member is engaged with the operating member, wherein rotation of the camshaft above engine cranking speeds causes the flyweight member to move the operating member from a first position to a second position. A vacuum release member is movably supported within the camshaft and is in engagement with the operating member wherein translational movement of the operating member causes movement of the vacuum release member.

Abstract: An internal combustion engine having a vacuum release mechanism that includes a centrifugally actuated member movably attached to the camshaft and having a vacuum release cam extending therefrom. The vacuum release cam is in lifting engagement with the exhaust valve assembly at crankshaft cranking speeds during a portion of the power stroke to relieve vacuum forces opposing motion of the piston. The vacuum release cam centrifugally pivots out of engagement with the exhaust valve assembly in response to the crankshaft attaining running speeds.

Abstract: A valve cam mechanism for a four-cycle engine includes an improved construction. The engine includes at least one camshaft having cam lobes to activate at least one of an intake valve and an exhaust valve. The camshaft defines an aperture next to at least one of the cam lobes. The aperture extends generally normal to an axis of the camshaft. A decompression mechanism is provided for manual starting of the engine. The decompression mechanism includes a shaft extending through the aperture. An actuator is affixed to the shaft for pivotal movement about an axis of the shaft. The actuator has a first section arranged to hold the intake or exhaust valve in an open position when the actuator exists in an initial position. A second section is arranged to initially retain the actuator in the initial position and to release the actuator from the initial position when the camshaft rotates. The shaft is rigidly supported by an inner surface of the aperture in part.

Abstract: A method of boot strap starting a diesel having a plurality of cylinders comprises the steps of initiating cranking the diesel and responsive to cranking forcing exhaust valves for all cylinders open during compression strokes. Thereafter, responsive to the engine rotational speed signal exceeding a first threshold, an exhaust valve for one cylinder is allowed to open and close in synchronous with movement of a piston in the cylinder. Further responsive to engine rotational speed exceeding a second threshold higher than the first threshold, cranking is discontinued and the remaining exhaust valves are allowed to open and close in synchronous with movements of pistons in their respective cylinders.

Abstract: A retainer retains a release member for engine valves of an internal combustion engine. The release member causes an engine valve to be actuated depending on various operating conditions of the engine, such as engine speed or oil level. The retainer retains the release member to at least one of a cam lobe and a cam gear. The release member may be substantially L-shaped and centrifugally responsive. Alternatively, the release member may be a substantially U-shaped yoke that at least partially surrounds a cam shaft. The retainer includes a pin that is substantially transverse and non-intersecting to the cam shaft. The pin may be substantially straight and interconnect to bosses that project from the cam gear. Alternatively, the pin may be substantially C-shaped and extend into apertures in the cam gear that extend in the axial direction of the cam gear.

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: A retainer retains a release member for engine valves of an internal combustion engine. The release member causes an engine valve to be actuated depending on various operating conditions of the engine, such as engine speed or oil level. The retainer retains the release member to at least one of a cam lobe and a cam gear. The release member may be substantially L-shaped and centrifugally responsive. Alternatively, the release member may be a substantially U-shaped yoke that at least partially surrounds a cam shaft. The retainer includes a pin that is substantially transverse and non-intersecting to the cam shaft. The pin may be substantially straight and interconnect to bosses that project from the cam gear. Alternatively, the pin may be substantially C-shaped and extend into apertures in the cam gear that extend in the axial direction of the cam gear.

Abstract: An internal combustion engine has a mechanical compression release including a cam, a cam follower, and a compression release member. The cam having a cam lobe and a base radius with a slot, and a compression release member disposed within the slot. The compression release member is substantially V-shaped and is comprised of a first portion, a second portion, and a bridging portion. The first portion has an auxiliary cam surface that extends slightly beyond the base radius and the second portion has sufficient mass to function as a flyweight. The bridging portion is substantially U-shaped and connects the first and second portions. The compression release member pivots about a pivot pin, that is disposed within the curved portion of the bridging portion. As the cam rotates, centrifugal forces cause the compression release member to pivot and to disengage from the cam follower.

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: 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: In an automatic decompression device of a small OHC-type engine, a decompression control mechanism A comprises a weight member 5 including a pivot portion 5A pivotably attached to a cam shaft 20 at a position apart from a center axis O20 of the cam shaft and having an outer periphery curved along an outer periphery of a cam sprocket 15 and a tip end portion that engages with an operating shaft 1, to swing around the pivot portion 5A outwardly by rotation of the cam shaft 20; and a bias member (coil spring 17) for biasing a portion of the weight member 5 that is apart from the pivot portion 5A toward the center axis of the cam shaft 20 in a swing area, wherein the tip end portion 5C of the weight member 5 that engages with the operating shaft is situated on an opposite side of the pivot portion 5A with respect to the center axis O20 of the cam shaft 20.

Abstract: An engine ignition timing control system for outboard motor having a propeller connected to the engine to be rotated and mounted on a boat such that the boat is propelled forward or backward. The engine is equipped with a decompression mechanism and is started by a recoil starter. In the system, at the time of engine starting, the ignition timing is set to a predetermined crank angle until the detected engine speed exceeds a first prescribed engine speed, while it is set to a value obtained by retrieving a table by at least the detected engine speed after the detected engine speed exceeds the first prescribed engine speed. And, the ignition timing is advanced until the detected engine speed is equal to or greater than a second prescribed value and is then returned to the retrieved value. With this, the engine speed can be reliably increased at starting, without need for a throttle opener or air-fuel ratio enrichment, thereby enhancing engine starting performance.

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 four-stroke internal combustion engine includes a cylinder block including a cylinder therein and having a piston reciprocally disposed within the cylinder. A piston is operably engaged with a crankshaft. At least one intake valve is reciprocally driven by a camshaft. At least one exhaust valve is reciprocally driven by the camshaft. A vacuum release mechanism includes an operating member reciprocally supported within the camshaft for translation along an axis. A centrifugally actuated flyweight member is engaged with the operating member, wherein rotation of the camshaft above engine cranking speeds causes the flyweight member to move the operating member from a first position to a second position. A vacuum release member is movably supported within the camshaft and is in engagement with the operating member wherein translational movement of the operating member causes movement of the vacuum release member.

Abstract: A compression release mechanism for an internal combustion engine wherein a rotatable pin positioned axially parallel to the camshaft is rotatably received in the cams, and has a lift member mounted at an axial end thereof. The pin is non-cylindrically shaped at one axial end thereof, and the non-cylindrically shaped end is received and secured into a correspondingly shaped bore disposed in a cylindrical hub extending perpendicularly from a one-piece flyweight. An optional adhesive can be used to secure the pin to the hub of the flyweight. According to a further optional embodiment, the hub can be crimped so as to engage the release pin. The disclosed configuration ensures a secure engagement and therefore avoids slipping between the release pin and the flyweight. Further, the design facilitates easy alignment of the pin with the flyweight during assembly. The flyweight can be a one-piece integral structure.

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 projection is formed on the outer circumference of an annular member and a stopping member is attached to a cylinder head supporting a camshaft thereon. A side surface of the projection comes into contact with a side surface of the stopping member to restrain a decompression cam from turning when the camshaft rotates in the normal direction. The stopping member does not apply any pressure to the annular member in a radial direction and the annular member does not exert any force on the camshaft. Consequently, frictional resistance against the rotation of the camshaft can be reduced and a loss in the output of the engine can be suppressed.

Abstract: An internal combustion engine has a mechanical compression release including a cam, a cam follower, and a compression release member. The cam having a cam lobe and a base radius with a slot, and a compression release member disposed within the slot. The compression release member is substantially V-shaped and is comprised of a first portion, a second portion, and a bridging portion. The first portion has an auxiliary cam surface that extends slightly beyond the base radius and the second portion has sufficient mass to function as a flyweight. The bridging portion is substantially U-shaped and connects the first and second portions. The compression release member pivots about a pivot pin, that is disposed within the curved portion of the bridging portion. As the cam rotates, centrifugal forces cause the compression release member to pivot and to disengage from the cam follower.

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: An internal combustion engine includes pressure relief devices that reduce pressure due to compression during startup, thereby decreasing the force needed to start the engine. A pressure relief valve mounts on top of the cylinder head and includes a duct to the combustion chamber leading to the valve and a second duct leading to the exhaust port so that gases in the combustion chamber may be vented through the exhaust system. A mechanical actuator having cables directed to each of the pressure relief valves for each of the cylinders manually actuates a first embodiment. A second embodiment includes a solenoid with wiring tied into a starter circuit that actuates the multiple valves from a single actuator.

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: 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 four-stroke internal combustion engine includes a cylinder block having a cylinder therein and a piston reciprocally disposed within the cylinder. The piston is operably engaged with a crankshaft. At least one intake valve and one exhaust valve is reciprocally driven by a camshaft. A vacuum release mechanism includes an operating member rotationally supported by the camshaft and has an operator disposed thereon. A centrifugally actuated flyweight member is attached to the operating member, wherein rotation of the camshaft above engine cranking speeds causes the flyweight member to rotate the operating member. A vacuum release member is reciprocally supported by the camshaft and in engagement with the operator wherein rotational movement of the operating member causes radial translation of the vacuum release member through the operator.

Abstract: A valve cam mechanism for a four-cycle engine includes an improved construction. The engine includes at least one camshaft having cam lobes to actuate intake and exhaust valves. A decompression actuator is affixed to the camshaft for pivotal movement. A holder section of the actuator is arranged to hold the intake or exhaust valve in an open position when the actuator exists in an initial position. A weight section is disposed opposite to the holder section relative to the pivot axis to place the holder section in the initial position. The actuator pivots when the weight section moves by centrifugal force to release the holder section from the initial position. The camshaft further has a projection extending radially and defining a first surface on which the stopper section abuts to inhibit the actuator from pivoting beyond a preset range. The cam lobe includes a base circle portion and a nose portion protruding from the base circle of the cam lobe.

Abstract: An engine decompression device includes an improved construction to release at an exceedingly slow engine speed. The engine has a camshaft that actuates at least one exhaust valve and extends generally vertically. The decompression device has an actuator mounted on the camshaft for pivotal movement about a pivot axis extending generally normal to an axis of the camshaft. The actuator includes a cam section that holds the exhaust valve in an open position and a sinker section that moves with centrifugal force produced by relatively slow rotation of the camshaft so as to release the cam section from holding the exhaust valve open.

Abstract: An internal combustion engine having a vacuum release mechanism that includes a centrifugally actuated member movably attached to the camshaft and having a vacuum release cam extending therefrom. The vacuum release cam is in lifting engagement with the exhaust valve assembly at crankshaft cranking speeds during a portion of the power stroke to relieve vacuum forces opposing motion of the piston. The vacuum release cam centrifugally pivots out of engagement with the exhaust valve assembly in response to the crankshaft attaining running speeds.

Abstract: A method for starting a camless internal combustion engine in response to a start signal, the internal combustion engine having a crankshaft and multiple cylinders each having one or more actuators for electronically actuating corresponding intake and exhaust valves, the internal combustion engine being mechanically coupled via the crankshaft to a starter motor, the starter motor being activated in response to the start signal, the method including the steps of: positioning each of the valves in accordance with a predetermined valve initial position, the valves being positioned so as to allow the flow of air in and out of each of the cylinders; rotating the crankshaft via the starter to a target idle speed for the engine; activating each of the valves in accordance with a predetermined valve activation sequence when the rotational speed of the crankshaft equals or exceeds the target idle speed; and activating each of the cylinders in accordance with a predetermined cylinder activation sequence after the valve

Abstract: A push rod operated multi-valve V-type engine particularly adapted for use in motorcycles or like vehicles and which engine is air cooled. The engine employs a very simplified construction and overhead valve actuating mechanism utilizing push rods. The push rods are contained within push rod tubes formed at one side of the engine that provide a neat appearance and ease of servicing without adversely affecting the air cooling. A composite cylinder head construction is employed, as well as an improved lubricating system for the pair of driven camshafts. Furthermore, a decompression system is incorporated in the valve actuating mechanism to lower the compression ratio so as to facilitate starting.

Abstract: A decompression device for a four-stroke engine, which drives the inlet valve and the exhaust valve by using the profile surface of a cam and rocker mechanism. This cam includes a guiding recess provided on the side surface thereof and a slot provided on the cam profile surface communicating with the guiding recess. The decompression device further includes a centrifugal member, received within the guiding recess, having a projecting portion and being rotatable and movable within the guiding recess, and a spring having two ends fixed to the cam and the centrifugal member.

Abstract: A valve cam mechanism for a four-cycle engine includes an improved construction. The engine includes at least one camshaft having cam lobes to activate at least one of an intake valve and an exhaust valve. The camshaft defines an aperture next to at least one of the cam lobes. The aperture extends generally normal to an axis of the camshaft. A decompression mechanism is provided for manual starting of the engine. The decompression mechanism includes a shaft extending through the aperture. An actuator is affixed to the shaft for pivotal movement about an axis of the shaft. The actuator has a first section arranged to hold the intake or exhaust valve in an open position when the actuator exists in an initial position. A second section is arranged to initially retain the actuator in the initial position and to release the actuator from the initial position when the camshaft rotates. The shaft is rigidly supported by an inner surface of the aperture in part.

Abstract: A compression release mechanism for use in a single or multi-cylinder engine to make the engine easier to hand start. The assembly includes a compression release shaft disposed substantially within the camshaft. The compression release shaft is formed in at least two segments and can therefore be formed accurately, repeatedly and cost effectively using powder metal technology. Consequently, the weight of the flyweight member that is attached to the compression release shaft can be accurately controlled, thereby allowing the compression release mechanism to disengage at a precisely known rotational velocity of the camshaft. The compression release shaft may engage one or more valve actuation devices, which in turn force exhaust valves open during starting engine speeds. The compression release mechanism is conveniently contained within the housing by a housing wall bearing against the flyweight member and a cam bearing against an end of the compression release shaft.

Abstract: An automatic valve for reducing compression in order to facilitate starting of a two-stroke internal combustion engine includes a movable valve (25) adapted to control a gas flow through an opening (16) provided in a wall of the combustion chamber of the engine. A spring (27) is adapted to move the movable valve (25) to an open position, and a drive actuated by an underpressure is adapted to move the movable valve (25) to a closed position against the action of the spring (27). The driver includes a cylinder (18), a piston (19) movable in the cylinder (18) and connected to the movable valve (25), and a conduit (22) connecting the cylinder (18) to a source of underpressure. A one-way valve (23) is provided in the conduit (22) for allowing an air flow in a direction a way from the (18) only, and a leak passage (30) is adapted to allow a small flow of air into the (18) for facilitating the opening of the movable valve (25) when operation of the engine has been stopped.

Abstract: A small and light decompression device of a four-stroke-cycle engine which cancels decompression operation surely when the engine rotational speed exceeds a predetermined speed to enable a stable engine starting. The device comprises an axial hole formed in a cam shaft, an oil pressure chamber formed in the axial hole, a decompression shaft reciprocating in accordance with oil pressure in the oil pressure chamber, a decompression pin which drives an exhaust valve to open in the compression stroke when the decompression shaft positions at a first position and stops the opening drive of the exhaust valve when the decompression shaft positions at a second position, a weight rotating in accordance with the engine rotational speed, and an oil pressure control valve interlocked with the weight to open and close a leak hole for controlling oil pressure in the oil pressure chamber.

Abstract: The invention is a decompression kit for large bore and/or high compression internal combustion engines. Specifically designed for engines such as the “Harley-Davidson®” “V-Twin®” or the “Sportster®” models, the invention vents high cylinder pressure and reduces the associated high starter torque required to turn the crankshaft when starting the engine, this in turn reduces the cranking amperage necessary to start the engine resulting in longer starter and battery life. A modified spark plug, steel tubing, and decompression valves are the main components of the invention. Cylinder pressure during the compression stroke is vented through the spark plug, tubing, and the decompression valve to make starting the engine easy.

Abstract: A spark prevention apparatus during the exhaust stroke of a four-stroke-cycle internal combustion engine is claimed. A valve operating assembly operates an intake or an exhaust valve. A switch is electrically connected to a primary winding of the engine and actuated by the valve operating assembly such that either the primary winding is electrically connected to ground during the exhaust stroke or the primary winding is electrically connected to an energy storage device during the exhaust stroke.

Abstract: An automatic decompression system for an internal combustion engine, especially a one-cylinder diesel engine, with at least one outlet and one inlet valve, which are activated by a camshaft (20) with at least one cam (1), wherein the outlet valve is lifted during starting to reduce the cranking resistance, wherein there is provided for lifting the outlet valve at speeds below a switching speed for changeover from decompression to compression a fully automatic lifting device, which engages in the cam (1) of the outlet valve and effects lifting of the outlet valve from the valve seat, wherein the lifting device is equipped with a bow-shaped member (22), pivoted in articulated relationship, disposed between cam (1) and a cam disk (2), which bow-shaped member has two articulated arms (11) and a crosspiece (14) joining them, and which at speeds below the switching speed occupies in the cam plane an engaged decompression position, in which it projects beyond the cam base circle, and which can be disengaged into a n

Abstract: In a valve control, which operates in the normal case purely electromagnetically without return spring and ancillary means of this kind, the unwanted collision between piston base and valve plate (8) is to be reliably avoided. An electromagnetically operating control device (2) for at least one gas-exchange valve in an internal combustion engine has a shaft (safety lock shaft) (18), which is provided with at least one cam (16), the shaft being drivable via the crankshaft at a ratio of 1:1. In the event of a disturbance of the electromagnetic valve actuation, the valve mechanism corresponding to the particular control device (2) can be displaced at least so far that the valve plate (8) has left the collision position thereby reliably avoiding a collision between piston base and valve plate (8). The control device can be used in a reciprocating engine, a piston compressor or a machine having the same operating principle.