Abstract: A hydraulic unit (5) for a cylinder head (2) of an internal combustion engine with a hydraulic, variable valve train (1) is provided. In the hydraulic unit, a high-pressure chamber (11), a medium-pressure chamber (12), and also a low-pressure chamber (16) used as a hydraulic medium reservoir are formed. The low-pressure chamber communicates merely via a choke opening (17) with the medium-pressure chamber, wherein the choke opening passes through a separating wall (18) extending between the low-pressure chamber and the medium-pressure chamber.

Abstract: A valve lift may be continuously varied by an apparatus that includes: an input cam provided on an input shaft; a mediating lever that moves upwards or downwards by the input cam and is formed with an output cam; a valve unit operated by the output cam; and a control device that is coupled to the mediating lever and is capable of changing a contact point between valve unit and the output cam of the mediating lever.

Abstract: In a variable valve opening property internal combustion engine, a roller link (22) is provided with a cam roller (31) at a free end thereof which engages a cam (3) of a camshaft (4) and a pressure surface (47) of a spring device (41). The roller link is pivotally supported by a bearing portion of a control link (21) which can be adjusted in position by using an actuator (14). The roller link is additionally provided with a roller shaft (31) that engages a slipper surface of a rocker arm (6). The pressure surface of the spring device may be contoured or otherwise inclined so that the direction of action of the spring device on the cam roller can be directed in an optimum direction irrespective of the adjusted position of the pivot point of the roller link.

Abstract: A mode-switching cam follower is disclosed, wherein the follower includes a body, a cam contact movably coupled to the body, and a latch member movably coupled to the body. A shape-memory alloy in communication with the latch member couples and decouples the latch member with the cam.

Abstract: An internal combustion engine including a variable valve mechanism that can avoid an unnecessary friction increase while preventing a hydraulic lash adjuster from pumping up. When a first engine speed is a critical rotation speed at which the inertia force of the variable valve mechanism exceeds the maximum load on a lost motion spring and a second engine speed is a critical rotation speed at which the inertia force of a valve and rocker arm exceeds the maximum load on a valve spring, the maximum loads are set such that the first engine speed is lower than the second engine speed.

Abstract: A variable valve actuation apparatus of an internal combustion engine has a multinodular-link motion converter, to vary at least a working angle. A position of rotation of a control shaft, variably adjusting the attitude of the motion converter, is set, so that, at a peak lift during a valve opening period, an angle ?2 between an extension line of a line segment connecting a first fulcrum corresponding to a drive-eccentric-cam center and a second fulcrum provided on a rocker arm and a line segment connecting the second fulcrum and a third fulcrum provided on the rocker arm at a position different from the second fulcrum at a middle working-angle control mode is less than both an angle ?1 between the two line segments at a minimum working-angle control mode and an angle ?3 between the two line segments at a maximum working-angle control mode.

Abstract: In a control apparatus and a method for an internal combustion engine, a first cylinder group in which both of the intake and exhaust valves of each of the engine cylinders thereof are controllably stopped; and a second cylinder group in which a lift of the intake valve of each of the engine cylinders thereof is variably controlled are provided. The lift of the intake valve of each of the engine cylinders of the second cylinder group is controlled in order for an engine torque when the intake and exhaust valves of each of the cylinders of the first cylinder group are controlled to be stopped to be approximately equal to the engine torque by the first cylinder group and the second cylinder group before the intake and exhaust valves of each of the cylinders of the first cylinder group are controlled to be stopped.

Abstract: [Object] It is to provide a variable valve mechanism that is downsized by providing a crank mechanism in place of an egg-shaped cam on an input shaft that is rotationally driven by a crankshaft of an internal combustion engine. [Means to Solve the Problems] A variable valve mechanism (10) having a variable mechanism (30) that changes the opening/closing amount of a valve (13), includes an input shaft (12) that is rotationally driven by an internal combustion engine. The input shaft (12) is provided with a crank mechanism (14) that is connected to the variable mechanism (30) and converts the rotational motion of the input shaft (12) into reciprocating motion for opening and closing the valve (13).

Abstract: A lost motion engine valve actuation system and method of actuating an engine valve are disclosed. The system may comprise a valve train element, a pivoting lever, a control piston, and a hydraulic circuit. The pivoting lever may include a first end for contacting the control piston, a second end for transmitting motion to a valve stem and a means for contacting a valve train element. The amount of lost motion provided by the system may be selected by varying the position of the control piston relative to the pivoting lever. Variation of the control piston position may be carried out by placing the control piston in hydraulic communication with a control trigger valve and one or more accumulators. Actuation of the trigger valve releases hydraulic fluid allowing for adjustment of the control piston position. Means for limiting valve seating velocity, filling the hydraulic circuit upon engine start up, and mechanically locking the control piston/lever for a fixed level of valve actuation are also disclosed.

Abstract: An example engine method utilizes a first intake valve actuated by a first camshaft once every four piston strokes and a second intake valve actuated by a second camshaft once every four piston strokes, but out of phase with the first intake valve actuation, to provide two-stroke operation. Transitions between two and four stroke operation are provided by deactivation and activation of the second intake valve. In this way, the engine may be selectively operated in a two stroke cycle or a four stroke cycle by activating or deactivating one of the intake valves while another of the intake valves continues to operate.

Abstract: An internal combustion engine includes a control shaft, an actuator, and an oil accumulation portion. The control shaft is configured to vary a lift amount of an engine valve in accordance with a rotational position of the control shaft. The actuator is configured to drive the control shaft to make the lift amount of the engine valve to be a start lift amount before the engine is started. The actuator includes a worm wheel and a worm. The worm wheel is provided at the control shaft and is disposed in an engine body. The worm is disposed below the control shaft and engages with the worm wheel. The oil accumulation portion is provided at at least one of the control shaft and the worm wheel and is configured to drop oil onto the worm in accordance with the rotation of the control shaft when the engine is started.

Abstract: Combustion mode transitions in a hybrid powertrain are managed by coordinated control of engine valve train, engine fueling and electric machine torque generation.

Abstract: A method and control module includes a pressure sensor data comparison module that compares measured pressure volume signal segments to ideal pressure volume segments. A valve actuation hardware remedy module performs a hardware remedy in response to comparing the measured pressure volume signal segments to the ideal pressure volume segments when a valve actuation hardware failure is detected.

Abstract: A decompression braking device in an endothermic engine (1) is provided of the type comprising a lever axle (2) on which a plurality of eccentric bushings (31) of a corresponding plurality of levers (3) provided with tappets (4) are rotationally and eccentrically mounted for actuating a plurality of exhaust valves (5), and a camshaft (30) for actuating the plurality of levers (3), the device is characterized in that it comprises an actuating member (6, 61) mounted externally to the lever axle (2) and connected to the latter by linkages (8, 9, 10), such that a respective rotation of the bushings (31) by a predetermined angular value (?), with consequent displacement of the hinging axis of the levers (3), corresponds to each excursion of the actuating member (6, 61).

Abstract: The switchable hydraulic lash adjuster uses balls that move radially in order to lock and unlock the switchable elements in the hydraulic lash adjuster. An axially movable piston acts on the ball to force it to engage and to allow it to disengage the inner housing.

Abstract: A continuous variable valve lift (CVVL) device opens and closes a valve by pressing a rocker arm through a rotational force transmitted from a drive cam. The CVVL device includes a drive arm, which is pivotably mounted such that one side thereof presses a rocker arm, a variable arm, which is pivotably mounted, and pushes and pivots the drive arm when pivoted, and a transmission arm, which is coupled with a transmission roller, which is located between the drive cam and the variable arm, at one end thereof, and is pivoted such that a position where the transmission roller comes into contact with both the drive cam and the variable arm is changed.

Abstract: A shaft comprising functional elements, such as an assembled camshaft for an internal combustion engine, a method for producing such shafts, and internal combustion engines equipped with such shafts. The functional elements each have a bore and are produced separately from the shaft main body, and the bore is subsequently press fit onto the shaft body to attach the functional element in an axially and rotationally fixed manner. The shaft is also provided with at least one roller bearing that includes at least one undivided roller bearing element which is mounted on the shaft body between two functional elements, for example, by press fitting.

Abstract: A device for hydraulic control of gas exchange valves of a reciprocating internal combustion engine which has slave cylinders in operative connection with one or more gas exchange valves and master actuators in operative connection with at least one cam provided with a basic and cam profile of a camshaft that is rotatably driven by the engine and can be hydraulically connected to the slave cylinders. The device also has a control device controlled by an actuating member, the device controlling the volume of hydraulic liquid fed to the slave cylinders, and at least one feed line, via which low pressure liquid from a pressure source can be fed to the device by means of at least one non-return valve. The actuators have displaceable vanes, a component carrying the vanes, and cells limited by walls. The vanes are in operative connection with the basic and cam profile of the cam.

Abstract: A variable valve lift apparatus according to an exemplary embodiment of the present invention includes a low lift cam, a high lift cam in parallel with the low lift cam, a low lift tappet body that selectively contacts the low lift cam, a high lift tappet body disposed within the low lift tappet body and constantly contacting the high lift cam, a guide portion that is connected with a valve and selectively connects the low lift tappet body and the high lift tappet body, and a lost motion spring that is disposed between the guide portion and the low lift tappet body and supplies restoring force to the low lift tappet body.

Abstract: A variable valve lift apparatus according to an exemplary embodiment of the present invention includes an outer body connected with a valve for opening and closing the valve, an inner body that is reciprocally disposed within the outer body and contacts a first input cam configured to an input shaft, a lost motion spring disposed between the outer body and the inner body, a connecting portion selectively connecting the outer body and the inner body, a hydraulic pressure supplying portion supplying hydraulic pressure to the connecting portion, and a lubrication circuit supplying lubricant to a contacting portion of the first input cam and the inner body.

Abstract: An Otto cycle, Atkinson cycle or supercharged internal combustion engine (10) and a timing mechanism therefor. The engine comprising: a cylinder (14) and a piston (12) reciprocally mounted within the cylinder (14) in which reciprocating movement of the piston is converted into rotational movement of an output shaft (28) by way of rollers (20, 24) engaging primary (22) and secondary (26) cam means which are affixed to, and rotatable with, the output shaft (28). The timing mechanism comprising cam means (52, 53) mounted on, and rotatable in unison with, the output shaft (28), a cam follower (54, 55) arranged to engage the cam means (52) and a linkage connecting the cam follower to a pivoting rocker arm for actuating the engine's induction and exhaust valves, the rocker arm pivot being adapted to be moveable on an arcuate locus centred on the axis of the output shaft (28).

Abstract: While an operating angle or a lift of an engine valve (211) is modified within a predetermined operating angle range or lift range, variation in an opening timing of the engine valve (211) is suppressed by displacing a rocker shaft (216b) relative to a drive shaft (213) such that an opening timing variation of the engine valve (211) accompanying angular variation in a straight line linking a center of the drive shaft (213) and a center of the rocker shaft (216b) and an opening timing variation of the engine valve (211) accompanying variation in a distance between the center of the drive shaft (213) and the center of the rocker shaft (216b) cancel each other out.

Abstract: A valve train of an internal combustion engine with at least one camshaft (1) on which at least one rotatable cam (2) is arranged fixed in the axial direction, wherein a rotationally fixed connection of the at least one cam (2) with the camshaft (3) can be selectively established and released by an associated coupling-like locking device (3).

Abstract: A valve drive device for an engine include a valve for opening or closing an opening of a port to a combustion chamber, a valve drive member for opening or closing the valve and a drive shaft for driving the valve drive member. The device also includes a variable valve timing mechanism for continuously changing a working angle of the valve corresponding to an operation state of the engine by changing a state of drive force transmission from the drive shaft to the valve drive member. A variable valve clearance mechanism is configured such that a valve clearance that is defined as a gap between the valve and the valve drive member can be set at a first value during a first condition in which the working angle of the valve is large to a second different value during a second condition in which the working angle of the valve is small.

Abstract: A variable valve lift apparatus may include a cam that is disposed to a camshaft and rotates, a rocker arm that is disposed to the camshaft and in which a relative rotation angle of the rocker arm around the camshaft is variable, a cam follower that contacts the cam, receives rotation of the cam, and pivots around the rocker arm, and a swing arm that contacts the cam follower and drives a valve.

Abstract: The cam follower has a roller, which is movable, between a first axial position and a second axial position and which alternately transmits elevations, which are different from one another. The cam has a cylinder-piston unit, which has a pressure medium space for moving the roller from the first axial position into the second axial position, and a spring means for moving the roller from the second axial position into the first axial position. The piston of the cylinder-piston unit is the roller and the roller has an end wall, which delimits the pressure medium space, and an annular collar which extends from said end wall and whose outer lateral surface serves as a cam pick-off surface. The inner lateral surface of the annular collar surrounds an outer section of the cylinder of the cylinder-piston unit.

Abstract: The invention provides an internal combustion engine equipped with a variable valve control system which switches the actions of an engine valve by sliding a rocker arm in the axial direction of the rocker arm shaft, while enabling the restriction on the sliding movement of the rocker arm to be removed in accordance with the timings of the actions of the rocker arms irrespective of the engine speed. The internal combustion engine includes an actuator that moves a rocker arm shaft in its axial direction, a trigger arm that engages with a rocker arm to prohibit the sliding movement of the rocker arm, and a trigger pin which is configured to be activated by an axial movement of the rocker arm shaft to bring the trigger arm into action, and to disengage the trigger arm from the rocker arm.

Abstract: A variable valve system includes a transmission mechanism T which transmits a valve actuating force to an inlet valve 11 and which varies a maximum lift amount of the inlet valve 11 and biasing members 60. A sub-cam 40 oscillatably supported on a holder 30 driven by a control member 70 has a roller 43 contacting the inlet cam 15a, a drive cam portion 46 outputting the valve actuating force, and acting portions A contacting the biasing members 60. The acting portions A are provided in the vicinity of the roller 43 so that biased contact points 45a1, 45b1 are positioned nearer to a cam contact point 43a than an oscillation center line Ls and that an acting line L1 of a biasing force is superposed on the roller 43 as viewed in the direction of the oscillation center line Ls.

Abstract: An exhaust valve control method may include displacing an exhaust valve in communication with the combustion chamber of an engine to an open position using a hydraulic exhaust valve actuation system and returning the exhaust valve to a closed position using the hydraulic exhaust valve actuation assembly. During closing, the exhaust valve may be displaced for a first duration from the open position to an intermediate closing position at a first velocity by operating the hydraulic exhaust valve actuation assembly in a first mode. The exhaust valve may be displaced for a second duration greater than the first duration from the intermediate closing position to a fully closed position at a second velocity at least eighty percent less than the first velocity by operating the hydraulic exhaust valve actuation assembly in a second mode.

Abstract: An internal combustion engine is equipped with a variable valve controlling system, in which the single actuator is disposed in a cylinder head on one side where one ends of the rocker-arm shafts are disposed, while enabling the single actuator to activate the rocker arms irrespective of the arrangement of the rocker-arm shafts. In the internal combustion engine, a hydraulic cylinder of a hydraulic actuator is disposed so as to transverse a timing chamber. Operation elements extend respectively from sidewalls of a plunger in the hydraulic cylinder, and activate respective rocker-arm shafts. In a motorcycle on which the engine is mounted, a frame member of a vehicle frame is disposed outside the hydraulic actuator.

Abstract: An intake valve control system comprises a torque control module and an opening control module. The torque control module controls torque output by an engine based on a torque output target. The opening control module opens intake valves of M cylinders of the engine to a first lift position when the torque output target is less than a torque threshold and selectively transitions the intake valves of N of the M cylinders to a second lift position. N and M are integers greater than zero, and N is less than M. The second lift position is open further than the first lift position.

Abstract: A continuous variable valve lift device includes a valve, which opens/closes a channel by means of reciprocation, a control shaft, which is mounted so as to be able to move toward or away from a reciprocation central axis of the valve, a pivotable shoe, which is pivotably coupled to the control shaft, includes a cam insertion part in a recess or through-hole shape and a slide face slidably contacting an end of the valve, and reciprocates the valve when pivoted, and a drive cam, which comes into contact with an inner wall of the cam insertion part, and pivots the pivotable shoe. Thereby, the continuous variable valve lift device can freely adjust a lift amount and a lift time of the valve without changing positions of the drive cam and camshaft, and thus be easily applied to an existing engine.

Abstract: A lost motion valve actuation system includes an engine brake housing and one or more hydraulic fluid supply passages extending through the housing. Master and slave pistons are slidably disposed corresponding bores in the housing. The master and slave pistons are used to provide selective actuation to one or more engine valves. An engine brake rocker arm disposed adjacent to the housing includes a master piston contact surface and a bias mechanism contact surface. A bias mechanism is disposed in the housing and includes a bias piston which extends from the housing. The bias piston biases the rocker arm out of contact with an engine cam during select engine operation modes, such as during a positive power mode of operation. The bias piston may be mechanically or hydraulically repositioned to permit the rocker arm to contact the engine cam during a second mode of engine operation, such as an engine braking mode.

Abstract: A fixation structure for a valve system rotation shaft of an internal combustion engine to support a camshaft with a cylinder head through the use of a lower cam holder and cam caps, which are formed separately from the cylinder head. The fixation structure eliminates the necessity of taking special vibration/noise control measures for a head cover thus preventing an increase in the cost, size, and weight of the head cover. A head external wall extends toward the head cover rather than toward a head middle surface in such a manner so as to cover the circumference of the lower cam holder fixed to a head middle surface. The connection to the holder fixation section is established with the base end of an external wall of the head cover abutted on the leading end of the head external wall.

Abstract: A variable valve lift apparatus may include a camshaft in which a cam is formed co-axially thereon; a variable shaft in which a groove is formed in an exterior circumference at a portion thereof, wherein the variable shaft is disposed in parallel with the camshaft; a variable guide, one end surface of which contacts the cam and the other end surface of which is inserted inside the groove of the variable shaft; a lever through which the variable shaft is rotatably inserted and on which the variable guide is slidably mounted; and a valve that is selectively lifted by the lever, wherein the variable guide selectively is inserted into the groove of the variable shaft to vary lift amount of the valve in accordance with rotation of the variable shaft.

Abstract: A valve actuation device may comprise a camshaft including first and second cams, the second cam having a larger lobe than the first cam. A valve lever includes a first follower component or surface adapted to follow the first cam and a second follower component or surface adapted to follow the second cam. The second follower component or surface may be mounted on or defined by an eccentrically-disposed device, which is rotatable relative to the first follower component or surface. When the rotatability of the second follower component or surface is locked by a latching device, the second follower surface translates the contour of the second cam into actuation of an engine valve and, when the second follower component or surface is freely rotatable, the first follower surface translates the contour of the first cam into actuation of the engine valve.

Abstract: A hydro-mechanical system is disclosed for actuating an outwardly opening valve of an engine, such as a crossover passage valve of a split-cycle engine. A developed embodiment includes a body having a plunger cylinder in hydraulic fluid communication with a valve cylinder. A plunger in the plunger cylinder is reciprocated to displace hydraulic fluid into the valve cylinder, the engine valve being opened by the hydraulic fluid displaced by the plunger into the valve cylinder and acting against the valve piston. A valve spring, preferably an air spring returns the engine valve to engage an outwardly facing valve seat to close a gas passage of the engine. Control valves and an energy reusing accumulator, along with valve seating control and lift brake features may also be included.

Abstract: A drive valve for an internal combustion engine comprising a variable hub profile for a valve having a lever supported on a variable support point by means of a switchable support element which provides possibilities for influencing the hub profile and alternatively and cumulatively, the cam is axially displaced such that various cam paths are active on the lever.

Abstract: A valve control apparatus includes a drive shaft; a control shaft including a control shaft main body configured to be rotationally controlled according to a state of engine, and a control eccentric shaft located eccentrically relative to a rotation center of the control shaft main body; a rocker arm swingably supported by the control eccentric shaft and configured to convert a rotational motion of the drive shaft to a swinging motion; and a swing cam configured to open/close an engine valve according to the swinging motion of rocker arm. Both ends of the control eccentric shaft are formed with fixing holes extending in a radial direction of the control eccentric shaft. The control shaft main body is formed with insertion holes passing through the control shaft main body in a radial direction of the control shaft main body. The insertion holes respectively face the fixing holes. The control eccentric shaft is fixed to the control shaft main body by bolts.

Abstract: A rocker arm changeover device for an engine includes a major rocker arm to drive intake or exhaust valves. A driven rocker arm is arranged in line with the major rocker arm. A changeover pin is movable within a first pin hole and a second pin hole and to change between engagement and disengagement of the major and driven rocker arms. The first pin hole coaxially matches the second pin hole through rocking motions of the major and driven rocker arms. A first pin is movable within the first and second pin holes between a disengagement position at which the first pin is retracted into the first pin hole and an engagement position at which the first pin protrudes from the major rocker arm. A second pin is movable relative to and coaxially with the first pin within the first pin hole.

Abstract: A driving assembly for a motor vehicle engine or exhaust brake comprises a driveshaft (1) supporting a plurality of rocking levers (7) which control, through rocking lever stems (6), exhaust valves (11), each rocking lever (7) comprising a recess (15) housing a disc element, each disc element (16) being eccentrically integral with the rocking lever supporting driveshaft (1) and each disc element operatively engaging the stem (8) of the exhaust valve (10) in an overlapping relationship with respect to the eccentric assembly (14) driven by the rotary driveshaft (1).

Abstract: An electro-hydraulic variable valve lift apparatus may include a valve unit housing of which a guide protrude portion is formed therein, a main piston which is slidably disposed in the valve unit housing and defines a valve adjusting oil chamber with the valve unit housing, a main spring which is disposed within the valve adjusting oil chamber and elastically supports the main piston on the guide protrude portion, a dependent piston which is slidably disposed within the valve unit housing, is guided along the guide protrude portion, reciprocates according to reciprocation of the main piston, and opens a valve, and a main oil supply portion which selectively supplies hydraulic pressure to the valve adjusting oil chamber.

Abstract: A cylinder head of an internal combustion engine having an electrohydraulic valve controller which includes a master unit (12), a slave unit (24), a hydraulic valve (4), a pressure relief space (18) and a pressure space (17) which is arranged in the direction of transmission between the master unit (12) and the slave unit (24) and can be connected to the associated pressure relief space (18) via the hydraulic valve (4). The master unit (12), the slave unit (24), the pressure space (17), the hydraulic valve (4), the pressure relief space (18) and a non-return valve (31) are preassembled in a common hydraulic housing (8), to form a pre-assembled hydraulic unit (3) which is fastened to the cylinder head (1) and which is connected to the hydraulic medium supply of the internal combustion engine via the non-return valve (31).

Abstract: An internal combustion engine that includes both a variable valve actuation system and an exhaust restriction system to provide engine braking are disclosed. Variable valve actuation and exhaust gas restriction are carried out in response to one or more engine parameters such as engine speed, engine load, vehicle speed, and/or manifold temperature and pressure. Variable valve actuation and exhaust gas restriction may be controlled to provide selective engine performance during positive power operation and/or during engine braking operation.

Abstract: Provided is a variable valve operating apparatus for an internal combustion engine, which can favorably improve the mounting environment of an actuator in the aspect of achieving the improvement of coolability and the reduction of stress. The apparatus includes a guide rail which is provided in the outer peripheral surface of a cylindrical part respectively fixed to a camshaft; a projection part which is disposed so as to be engageable and disengageable with the guide rail; and an actuator which is disposed so as to oppose the cylindrical part and can protrude the projection part toward the guide rail. At least a part of the actuator is disposed so as to fit in a oval-shaped region which is virtually obtained by linking a base circle of a main cam and a base circle of a main cam seen from the axial direction of the camshaft in a state in which the projection part is not protruded toward the guide rail.

Abstract: A variable valve system includes a variable valve lifter for changing a first lift amount of one or more valves at a predetermined engine speed; a variable valve timing portion for controlling opening and closing timing of one or more valves; and a cylinder deactivation portion that changes a second lift amount of two or more valves in an alternating pattern.

Abstract: A control apparatus for an internal combustion engine includes an oil pressure regulating valve having a solenoid, a variable cam phase mechanism for changing a cam phase, and an ECU for controlling the oil pressure regulating valve. The ECU includes an actual cam phase detecting unit, a target cam phase setting unit, a feedback control unit, a coil temperature detecting unit, a circuit resistance calculating unit, and an integral term initial value calculating unit. When an integral term is initialized, the feedback control unit sets the holding output duty as the integral term.

Abstract: A continuous variable valve lift apparatus according to an exemplary embodiment of the present invention includes an input cam disposed to an input shaft, a first shaft in parallel with the input shaft, a first link connected with the first shaft, a second link rotatably connected to the first link, an output cam that is rotatably connected with the second link and configured with a contact portion contacting the input cam, a second shaft disposed to the output cam parallel with the input shaft, at least one valve unit that is opened and closed by the output cam, and a control part that controls a position of the second shaft.

Abstract: In a V-type engine for a vehicle, in which a hydraulic valve rest mechanism which selectively holds at least one of an intake valve and an exhaust valve corresponding to a part of plural cylinders in a valve-closed rest state in correspondence with a vehicle running status is provided in a valve actuation unit, and a hydraulic controller which controls hydraulic pressure of the valve rest mechanism is provided in a main engine body, to reduce the distance of oil passage from the hydraulic controller to the hydraulic valve rest mechanism and simplify the structure of the oil passage. A hydraulic controller is provided on at least one side surface of a cylinder head, and may be generally oriented along a line which is substantially parallel to a central axis of a cylinder bore.

Abstract: A method is disclosed for controlling cylinder valve switching between a first valve condition and a second valve condition for transitioning between combustion modes of an engine. The method includes adjusting timing of a signal to switch between the valve conditions based on an oil degradation condition from an oil sensor, wherein the combustion modes include spark ignition and homogenous charge compression ignition.