Abstract: A type II valve train assembly that selectively opens first and second intake valves and first and second exhaust valves is provided. The valve train assembly includes an intake rocker arm assembly and an exhaust rocker arm assembly. The valve train assembly is configurable for operation in any combination of activated and deactivated states of engine braking and cylinder deactivation. The exhaust rocker arm assembly includes a first exhaust rocker arm, a second exhaust rocker arm and an engine brake exhaust rocker arm. A first exhaust HLA is associated with the first exhaust rocker arm. A second exhaust HLA is associated with the second exhaust valve. An exhaust actuation assembly selectively actuates to alter travel of the first and second exhaust HLA's to change a state of cylinder deactivation between activated and deactivated.

Abstract: A method of determining a condition of a component (e.g., valves) of an engine having a manifold air pressure sensor during a cold test includes providing pressurized air to an intake of the engine. The method includes rotating a crankshaft of the engine. The method includes measuring pressures with the manifold air pressure sensor as a function of crankshaft rotational position. The method includes comparing the pressures with a predetermined baseline. The method includes indicating a condition of the component based on the comparison of the pressures with the baseline.

Abstract: A valve actuation system comprising a valve actuation motion source configured to provide a main event valve actuation motion to at least one engine valve via a main motion load path that comprises at least one valve train component. The valve actuation system further includes a lost motion component arranged within a first valve train component in the main motion load path, the lost motion component being controllable to operate in a motion conveying state or a motion absorbing state. The valve actuation system also comprises a high lift transfer component arranged in the main motion load path, with the high lift transfer component being configured to permit the main motion load path to convey at least a high lift portion of the main event valve actuation motion when the lost motion component is in the motion absorbing state.

Abstract: A type II valve train assembly that selectively opens first and second intake valves and first and second exhaust valves is provided. The valve train assembly includes an intake rocker arm assembly and an exhaust rocker arm assembly. The valve train assembly is configurable for operation in any combination of activated and deactivated states of engine braking and cylinder deactivation. The exhaust rocker arm assembly includes a first exhaust rocker arm, a second exhaust rocker arm and an engine brake exhaust rocker arm. A first exhaust HLA is associated with the first exhaust rocker arm. A second exhaust HLA is associated with the second exhaust valve. An exhaust actuation assembly selectively actuates to alter travel of the first and second exhaust HLAs to change a state of cylinder deactivation between activated and deactivated.

Abstract: A self-resetting single-valve hydraulic drive device and method based on primary and secondary pistons for a push rod engine is provided. A primary driving piston and a secondary driving piston are respectively provided on a rocker arm body and a valve bridge body. The secondary driving piston is connected to an exhaust valve. A driving oil passage connects the primary driving piston, the secondary driving piston and a drive control valve. When the drive control valve opens the driving oil passage, the primary driving piston and the secondary driving piston realize a hydraulic linkage. During a drive lift, the rocker arm body and the valve bridge body do not move, and the secondary driving piston opens the exhaust valve. In the beginning of a positive-power lift, a primary piston body oil passage and a secondary piston oil passage are closed, and the secondary driving piston is automatically reset.

Abstract: A valve bridge comprises a central body and at least first and second valve interface portions extending from the central body, each of the at least first and second valve interface portions defining a chamber configured to receive an engine valve and corresponding valve spring and spring retainer. Each chamber comprises a valve bridge control surface configured to selectively contact at least one of the corresponding valve spring and spring retainer, wherein each valve bridge control surface is a concave surface configured to extend downward around the corresponding valve spring.

Abstract: Methods and systems are provided for a valve bridge of an internal combustion engine. In one example, a valve bridge comprises a first arm, a longitudinally opposing second arm, and one or more interior walls forming a passage extending laterally through at least a portion of the valve bridge, the passage disposed between the first arm and second arm and forming a first main opening and an opposing, second main opening. A central support structure is disposed within the passage and is formed by the one or more interior walls.

Abstract: A valve train lever for actuating a valve of a reciprocating piston engine, in particular an internal combustion engine. The valve train lever comprises a lever arm, which is pivotally movable about a pin; a tapping element, which lies against or can be made to lie against a cam of a camshaft of the reciprocating piston engine; a coupling mechanism, by way of which the tapping element is coupled to the lever arm spring-elastically in a first state and rigidly in a second state; and an actuating element, which is connected to the lever arm and lies against or can be made to lie against a valve tappet of the valve.

Abstract: A system for actuating engine valves may include a valve bridge having a main event rocker interface portion, a first valve interface portion and a second valve interface portion extending in generally opposite directions from the main event rocker interface portion. The second valve interface portion may include an open end including a slot for receiving a bridge pin. The slot permits the valve bridge to be removed from the actuation system without removal of the main event rocker or other actuating components, such as an auxiliary rocker. The valve bridge can be removed from the valve train without requiring removal of other actuation system components, such as auxiliary rockers or main event rockers. A single valve bridge configuration can be used with different valve spans, which may occur among different cylinder sizes in a given engine family, or across different engine families.

Abstract: A system for actuating engine valves may include a valve bridge having a main event rocker interface portion, a first valve interface portion and a second valve interface portion extending in generally opposite directions from the main event rocker interface portion. The second valve interface portion may include an open end including a slot for receiving a bridge pin. The slot permits the valve bridge to be removed from the actuation system without removal of the main event rocker or other actuating components, such as an auxiliary rocker. The valve bridge can be removed from the valve train without requiring removal of other actuation system components, such as auxiliary rockers or main event rockers. A single valve bridge configuration can be used with different valve spans, which may occur among different cylinder sizes in a given engine family, or across different engine families.

Abstract: A cylinder head cover and a method for producing a cylinder head cover are disclosed. The method for producing a cylinder head cover may include: providing at least two metallic bearing bridges including a respective through-opening for mounting at least one camshaft and aligning the respective through-opening of the at least two bearing bridges axially relative to one another; connecting at least one metallic connection element to the at least two bearing bridges in a fixed manner so that the at least two bearing bridges are fixed and aligned relative to one another; and at least partially overmoulding the at least two bearing bridges and the at least one connection element with a plastic material.

Abstract: A valvetrain for an engine includes a pair of valves that are disposed in a spaced apart relation to one another, and in which each of the valves has an elongated valve stem. The valvetrain further includes a valve bridge that is coupled to the pair of valves. The valve bridge is configured to define a pair of receptacles to at least partly receive the pair of valve stems therein. The valve bridge further defines a central recess that is located midway between the pair of receptacles and disposed in a co-planar relationship with the pair of receptacles.

Abstract: In a DOHC-type internal combustion engine in which a pair of intake valves and a pair of exhaust valves are disposed around a plug hole, and two pairs of rocker arms are respectively interposed between intake-side and exhaust-side camshafts and the intake valves and the exhaust valves, first and second support portions of one pair of the rocker arms are disposed between the intake valves and the exhaust valves in a direction orthogonal to axes of the intake-side and exhaust-side camshafts and around the plug hole, and the third and fourth support portions of an other pair of the rocker arms are disposed outside a region between the intake valves and the exhaust valves in the direction orthogonal to the axes of the intake-side and exhaust-side camshafts.

Abstract: A valve operating apparatus for use in an internal combustion engine includes an intake cam 38, an intake rocker arm 33 rotatable about a rotational shaft 35 and driven by the intake cam 38, and an intake valve 40 pushed by a pusher 70 of the intake rocker arm 33, the internal combustion engine has a cylinder assembly 12L lying horizontally, and the intake rocker arm 33 has a weight 67 adjusting the center of gravity of the rocker arm 33 to position the pusher 70 above the rotational shaft 35 while the intake cam 38 is held out of abutting contact with the intake rocker arm 33.

Abstract: In a variable-flow-rate valve mechanism, a valve is fitted into an attachment hole of an attachment member. The valve allows for play with the attachment member, and includes a valve body provided with a valve surface. A valve shaft is integrally formed in the center of a head portion of the valve body. A stopping member is provided to a leading end portion of the valve shaft. A leaf spring is provided to the valve shaft. The leaf spring includes a folded-back portion formed by bending. An insertion hole is formed in one end portion of the leaf spring. A cutout portion is formed in another end portion of the leaf spring. The one end portion of the leaf spring is fixed to the attachment member and the other end portion of the leaf spring is pressed to the head portion of the valve body.

Abstract: An internal combustion engine optimizing small-size arrangement of the valve drive mechanism, considering that the exhaust valve diameter is smaller than the intake valve diameter. Intake and exhaust valves are in a radial arrangement, intake and exhaust cam surfaces are inclined relative to intake and exhaust cam axes, intake and exhaust rocker arm support members are inclined correspondingly in the same way and disposed between an intake camshaft and an exhaust camshaft. Pivotal support base portions of intake rocker arms and pivotal support base portions of exhaust rocker arms are disposed such that the distances thereof from a joining surface joining a cylinder head and a cylinder body are different.

Abstract: A rocker arm for an engine valve actuator assembly is disclosed. The rocker arm may include a rocker arm body disposed between a first and second arm end. Furthermore, a rocker arm bore and an adjuster compartment may be defined proximal to the second arm end. The rocker arm may further include a roller positioned at the first arm end and operably coupled to a cam, the cam configured to actuate the rocker arm between a first and second position. The rocker arm may further include a shaft inserted through a shaft mounting aperture and the rocker arm is configured to rotate about the shaft between the first and second positions. Furthermore, a fluid passage may be defined within the rocker arm body extending between a first passage opening formed in a bearing surface of the shaft mounting aperture and a second passage opening that opens into the adjuster compartment.

Abstract: A pushrod assembly for an internal combustion engine comprises a pushrod having a first end and a second end, the first end being configured to receive valve actuation motions from a valve actuation motion source and the second end being configured to impart the valve actuation motions to a valve train component. The pushrod includes a resilient element engagement feature. The pushrod assembly includes a fixed support and a resilient element operatively connected to the resilient element engagement feature and the fixed support. The resilient element is configured to bias the pushrod, via the resilient element engagement feature, toward the valve actuation motion source. An internal combustion engine may comprise the pushrod assembly described herein. A follower assembly may be provided to maintain contact between second end of the pushrod and the valve train component.

Abstract: A multi-valve actuating valve bridge for an engine is provided. The valve bridge includes a rocker arm engaging tappet head and at least two arms extending transversely of the rocker arm and engaging the tappet head. The valve bridge further includes a valve stem guide pocket provided on each of the arms. The valve stem guide pocket includes a valve stem contact face and a tapered surface extending from the valve stem contact face towards an opening of the valve stem guide pocket. The tapered surface defines an inverted frusto-conical cavity. A first inner diameter of the valve stem guide pocket at the valve stem contact face is greater than a second inner diameter of the valve stem guide pocket at the opening.

Abstract: A cylinder head for an internal combustion engine is provided which include a valve spring boss having a central opening for accommodating a valve and having a contact area for retaining said valve. The contact area has a first portion and a second portion. The first portion being ring-shaped and delimited by the opening, and the second portion being radially protruding from the first portion.

Abstract: A multi-valve actuating valve bridge for an engine is provided. The valve bridge includes a rocker arm engaging tappet head and at least two arms extending transversely of the rocker arm and engaging the tappet head. The valve bridge further includes a valve stem guide pocket provided on each of the arms. The valve stem guide pocket includes a valve stem contact face and a tapered surface extending from the valve stem contact face towards an opening of the valve stem guide pocket. The tapered surface defines an inverted frusto-conical cavity. A first inner diameter of the valve stem guide pocket at the valve stem contact face is greater than a second inner diameter of the valve stem guide pocket at the opening.

Abstract: In a control device for an internal combustion engine includes an intake valve, a variable valve mechanism capable of controlling a closing timing and an operating angle of the intake valve continuously and variably, a detection unit for detecting a possibility of pre-ignition, and a throttle for controlling an intake air amount such that when the possibility of pre-ignition is detected, the intake valve closing timing is retarded from bottom dead center by increasing the intake valve operating angle, the control device includes, an operating angle upper limit limiting value calculation unit that calculates an operating angle upper limit limiting value for limiting an upper limit value of the intake valve operating angle, and a throttle opening upper limit limiting value calculation unit that calculates a throttle opening upper limit limiting value for limiting an upper limit value of a throttle opening on the basis of the intake valve operating angle.

Abstract: A valve control apparatus includes first and second engine valves; a first drive cam configured to rotate integrally with the drive shaft; a second drive cam provided on the drive shaft and configured to rotate integrally with the drive shaft; a swing cam configured to swing; a transmission mechanism configured to convert a rotation of the first drive cam into a swinging force and to transmit the swinging force to the swing cam; a first swing arm configured to open the first engine valve by a swing of the swing cam; a second swing arm configured to open the second engine valve by a rotation of the second drive cam; a control mechanism configured to vary a swing amount of the swing cam by varying an attitude of the transmission mechanism; and a connection changeover mechanism configured to connect and disconnect the first swing arm with/from the second swing arm.

Abstract: A valve mechanism is disclosed for a cylinder of an internal combustion engine which comprises two gas exchange poppet valves mounted in a cylinder head, a bridge 122 acting on the two valves, a cam for actuating the two valves, a slider 124 movable by the cam and slidable relative to the bridge 122, and a hydraulically controlled locking system having a latched position in which the slider transmits the force of the cam to the bridge 122 to actuate the two valves and a released position in which the valves are deactivated and the slider slides freely relative to the bridge. In the invention, the slider 124 is urged towards the cam by a spring 134 acting between the slider 124 and the cylinder head.

Abstract: A system and method of actuating one or more engine valves is disclosed. In one embodiment, the system comprises: a valve train element; a rocker arm pivotally mounted on a shaft and adapted to rotate between a first position and a second position, the rocker arm selectively receiving motion from the valve train element; a valve bridge disposed above the one or more engine valves; and a lost motion system disposed in the valve bridge.

Abstract: A coupler plate for a multi-valve system of an internal combustion engine. The coupler plate includes an elongated planar body and through holes on opposite ends. The through holes may be either closed or open ended, and of sufficient size to insert valve stems of valves for an internal combustion engine valve system.

Abstract: A valve bridge configured to engage an engine valve is disclosed. The valve bridge includes a bridge cavity formed within a center portion of the valve bridge and including a bottom surface. A hydraulic lash adjuster is slidably disposed within the bridge cavity.

Abstract: A valve opening arrangement includes a first contact surface on a first member, and a second contact surface on a second member discrete from the first member. A first and a second opening are provided, and a first and a second valve movable to open and close the first and second opening, respectively, are provided. A yoke is arranged to move the first valve and not the second valve when contacted by the first contact surface and is arranged to move the first valve and the second valve when contacted by the second contact surface.

Abstract: An internal combustion engine is described having a valve mechanism that comprises an SCP camshaft operating two sets of valves. The first set of valves is operated via a summation rocker system such that the valve lift characteristic results from the combination of two cam profiles. The second set of valves has a valve lift characteristic that is different from that of the first set. In the invention, changing the valve lift characteristic of the first set of valves by varying the phase of the inner shaft of the SCP camshaft relative to the outer tube of the SCP camshaft serves additionally to alter the operation of the second set of valves.

Abstract: The invention relates to an internal combustion engine comprising a valve drive which is arranged in the region of the cylinder head and is used to actuate a valve. Said internal combustion engine comprises a first drive means that can be rotated about a first rotational axis, a connecting rod that is connected to the first drive means in an articulated manner by means of a first connecting rod articulation, and a guiding element which is used to guide the connecting rod, can be pivoted about a guiding axis, and is connected to a second articulation of the connecting rod in an articulated manner. The position of the first rotational axis can be modified in relation to the cylinder head.

Abstract: There is provided herein a valve mechanism for an internal combustion engine comprising a rocker arm and a valve bridge. There is also described herein a valve bridge.

Abstract: An internal combustion engine has one or more engine cylinders (12) within which fuel is combusted and a pair of cylinder valves (14, 16) spring-biased (22, 24) closed but open in unison to place the respective cylinder in flow communication with one of an intake and an exhaust. A bridge (34) bridges ends of the pair external to the cylinder and has a spherically concave depression (42) in a face that is opposite a face that bears against the ends of the pair. The depression is located intermediate locations at which the ends of the pair bear against the bridge. A pivot foot (44) has a spherically convex surface (46) seated with substantial conformity in the depression and a flat surface (48) opposite the spherically convex surface. The flat surface of the pivot foot abuts a flat surface (50) of a rocker (30) that when rocked acts through the pivot foot and bridge to open the respective pair of valves.

Abstract: Apparatus and method are disclosed for converting an internal combustion engine from a normal engine operation (20) to an engine braking (or retarding) operation (10). The apparatus has an actuation means (100) containing two braking pistons (160) slidably disposed in the valve bridge (400) between an inoperative position (0) and an operative position (1). The apparatus also has a flow control valve (50) for supplying control fluid to the actuation means (100) with two levels of pressure. At the first level or lower pressure, the braking pistons (160) will stay in the inoperative position (0), and a gap (234) is formed between the valve bridge (400) and the exhaust valves (300) to skip the motion from the lower portion of the cam (230) for the normal engine operation (20).

Abstract: An electromagnetically-driven valve includes intake valves that are provided in a gasoline engine and that are arranged side by side; a valve plate that connects the intake valves to each other, wherein driving force that is generated by electromagnetic force is transferred to the valve plate; and a changing mechanism that is fitted to the valve plate. The changing mechanism changes the valve drive state between the two-valve drive state, in which both of the intake valves are driven, and the one-valve drive state, in which one of the intake valves is driven and the other intake valve is stopped.

Abstract: A system and method of actuating one or more engine valves is disclosed. In one embodiment, the system comprises: a valve train element; a rocker arm pivotally mounted on a shaft and adapted to rotate between a first position and a second position, the rocker arm selectively receiving motion from the valve train element; a valve bridge disposed above the one or more engine valves; and a lost motion system disposed in the valve bridge.

Abstract: An internal combustion engine has one or more engine cylinders (12) within which fuel is combusted and a pair of cylinder valves (14, 16) spring-biased (22, 24) closed but open in unison to place the respective cylinder in flow communication with one of an intake and an exhaust. A bridge (34) bridges ends of the pair external to the cylinder and has a spherically concave depression (42) in a face that is opposite a face that bears against the ends of the pair. The depression is located intermediate locations at which the ends of the pair bear against the bridge. A pivot foot (44) has a spherically convex surface (46) seated with substantial conformity in the depression and a flat surface (48) opposite the spherically convex surface. The flat surface of the pivot foot abuts a flat surface (50) of a rocker (30) that when rocked acts through the pivot foot and bridge to open the respective pair of valves.

Abstract: The invention concerns a method for controlling the operation of a cylinder assembly according to which the following phases are carried out during the same operating cycle: an exhaust opening phase (L1); a first inlet opening phase (L2) during a compression phase of the piston, and; a second inlet opening phase (L3) subsequent to the first. The second inlet opening phase (L3) begins once the piston reaches a position located in the second third of the travel thereof, in an expansion phase, and the first phase (L1) is carried out entirely during the exhaust opening phase (L1). The invention also concerns an internal combustion engine that operates according to the aforementioned method, and to a motor vehicle equipped with this engine.

Abstract: An intake valve assembly of an internal combustion engine. The intake valve assembly comprises a primary valve, a secondary valve mounted about the primary valve coaxially therewith, a primary valve spring for normally biasing the primary valve toward a closed position, a secondary valve spring for normally biasing the secondary valve toward a closed position, and a secondary valve lifter fixed to the primary valve and axially spaced from the secondary valve when both the primary and secondary valves are in closed positions. The secondary valve is operated mechanically by the secondary valve lifter and fluidly in response to pressure differential between the intake passage and the combustion chamber. The secondary valve is engageable with the primary valve through the secondary valve lifter after opening of the primary valve. The primary and secondary valve springs are normally contracted for continuously biasing the valves toward the closed position thereof.

Abstract: A device for retaining a valve bridge is disclosed. The valve bridge is engaged with a plurality of valves. The device has a first base member. The first base member is configured to engage at least one of the plurality of valves. The device also has a first latching member. The first latching member extends from the first base member. The first latching member is configured to engage and retain the valve bridge in engagement with the plurality of valves.

Abstract: An arm coupling mechanism for selectively switching a double valve variable control and single valve variable control. The single valve variable control is achieved in a condition in which a large lift arm and a second rocking cam arm are coupled together with a pin. The second rocking cam arm for moving a second valve includes a pin hole, in which the pin is inserted, formed therein. The position of the pin hole is set so that a pin switching operation can be executed when control is provided to achieve an operating angle, at which the single valve variable control is to be started for reduced NOx. A second driving cam is adapted to have a cam height greater than a cam height of a first driving cam.

Abstract: A hydraulic cam follower (1) for the simultaneous actuation of several equal-acting gas-exchange valves is provided, especially for a tappet pushrod valve train of an internal combustion engine, and includes an outer part (2), whose base (3) forms or is at least indirectly connected to a cam contacting surface (4) and from whose head (5) hollow-cylindrical guides (6) extend in the same number as the equal-acting gas-exchange valves in a direction towards the base (3). Each guide (6) is formed by a cutting process, such as internal round reaming or internal round broaching, and a housing (7) of a hydraulic play compensation element (8) is provided in each guide with its outer casing (9) fine-machined by grinding, which housing (7) sits with its bottom side (10) on an inner side (11) of the bottom (3) of the outer part (2).

Abstract: A variable mechanical valve control for an internal combustion engine is provided having an underhead camshaft for adjusting a valve stroke and an opening and closing time, making it possible to achieve a very compact transmission gear between the push rod drive and the intake and exhaust valves, to reduce the number of components required for the transmission gear, and to obtain a mechanical, completely variable valve train with an underhead camshaft.

Abstract: A disc valve system for a piston driven internal combustion engine. The disc valve system comprises at least one rotating disc valve and an intermediate seal member. The disc is mounted between a cylinder head manifold having exhaust and intake ports and an engine cylinder housing the piston and defining a combustion chamber. The disc comprising sequencing ports to be brought into periodic communication with the exhaust and intake ports at cyclic intervals of the rotating movement thereof, thereby providing for the exhaust and intake ports to be brought into periodic communication with the combustion chamber. The intermediate seal member is mounting between the disc and the cylinder so as to seal the combustion chamber at a junction of the disc and the cylinder. The intermediate seal member comprising a dynamic seal for contact with the disc and a stationary seal for sealing contact with the engine cylinder.

Abstract: A valve assembly for an internal combustion engine includes: at least two valves supported by a pair of valve stem holders; a bracket; a closing actuator for pivoting and closing the valves upon contact with a closing lobe of a camshaft; one or more opening actuators for opening at least one of said valves upon contact with an opening lobe of the camshaft; and one or more Belleville spring washers, allowing for an adjustment of a sealing load when the respective valves are closed.

Abstract: A system comprising of an engine having a first group of cylinders and a second group of cylinders, a first variable valve system in said first group, a second variable valve system in said second group, and a controller for determining degradation of operation of at least one of said first and second variable valve systems, said controller determining said degradation in response to controller errors of said valves and differences between operation of said first and second valve systems.

Abstract: Method and arrangement for delivering EGR gas to combustion spaces in a multi-cylinder, four-stroke internal combustion engine. Each cylinder, with an associated piston, has at least one inlet valve and at least one exhaust valve (10) for controlling fluid interconnection between the combustion space in the cylinder and an intake system and an exhaust system, respectively. A rotatable camshaft (18) having a cam curve (23) is designed to interact with a cam follower (17) for operation of the exhaust valve (10) during a first opening and closing phase. The cam curve (23) is also designed to interact with a second cam follower (20) during a second opening and closing phase which is phase-offset in relation to the first aforementioned opening and closing phase. This configuration facilitates the cylinder being connected to the exhaust system during the induction stroke, once the exhaust stroke is completed.

Abstract: A control device for a gas exchange valve of an internal combustion engine having a multi-membered transmission comprising at least one driving element (1), actuating elements (2) each of which actuates one gas exchange valve (3), a transmission element (9) which is hinge-connected between the at least one driving element (1) and an actuating element (2) which acts on a gas exchange valve (3), a cam joint (15) between the transmission elements (9) and an area of the housing (5) of the control device, in which a first bearing area which is provided on the transmission element (9) and a second bearing area which is provided in the housing area are adjustable with respect to one another during operation of the engine, is to be manufacturable easily for extremely accurate operation.

Abstract: A valve system is provided to eliminate a play at connection portions in a valve characteristic varying mechanism and to enhance the accuracy in control of valve operation characteristics.

Abstract: A hydraulically controlled actuator for actuation of an exhaust-side gas exchange valve of an internal combustion engine, containing a control piston that is displaceable within a cylinder and, with piston sides facing away from one another, delimits pressure chambers, of which the one pressure chamber impinges upon the gas exchange valve in the closing direction and the other pressure chamber impinges upon the gas exchange valve in the opening direction. In the actuator is provided at least one spring element, which can be brought into a preloaded state by the control piston moving in the closing direction of the gas exchange valve, and whose stored potential energy accelerates the gas exchange valve in the opening direction at least at the beginning of an opening phase, is provided. This results in a reduction in the energy expended in the context of valve actuation.

Abstract: A barrel engine has an elongated power shaft defining a longitudinal axis. A plurality of cylinders surround the longitudinal axis, with each having a closed end and an open end. An intake system introduces a combustible mixture of air and fuel into each of the cylinders. The power shaft has an intake lobe and an exhaust lobe extending therefrom. The intake system includes an intake valve and an exhaust valve for each of the cylinders. A valve actuation mechanism includes an intake rocker arm with one end in mechanical communication with the intake lobe, the other end in mechanical communication with the intake valve, and a mid-portion that is pivotally supported. The mechanism also includes an exhaust rocker arm with one end in mechanical communication with the exhaust lobe, the other end in mechanical communication with the exhaust valve, and a mid-portion that is pivotally supported.