A valve system for an engine includes two cams each having a follower, a summation lever coupled to the followers, a lash adjuster, a valve actuating rocker pivotably coupled to the summation lever and resting on the lash adjuster, a control spring urging the summation lever to compress the lash adjuster, a stop limiting an expansion of the control spring, a bore, a plunger which moves in the bore, and an abutment surface. The control spring acts on the summation lever via the plunger. A plunger end engages with the summation lever. A point of contact between the plunger and the summation lever is displaced in a direction transverse to a plunger axis during a pivoting movement of the summation lever. A plunger shoulder is arranged a distance from the plunger end to contact the abutment surface to limit a plunger displacement in a direction compressing the lash adjuster.

A valve system for an engine includes two cams each having a follower, a summation lever coupled to the followers, a lash adjuster, a valve actuating rocker pivotably coupled to the summation lever and resting on the lash adjuster, a control spring urging the summation lever to compress the lash adjuster, a stop limiting an expansion of the control spring, a bore, a plunger which moves in the bore, and an abutment surface. The control spring acts on the summation lever via the plunger. A plunger end engages with the summation lever. A point of contact between the plunger and the summation lever is displaced in a direction transverse to a plunger axis during a pivoting movement of the summation lever. A plunger shoulder is arranged a distance from the plunger end to contact the abutment surface to limit a plunger displacement in a direction compressing the lash adjuster.

Methods and systems are provided for a valve lift control device. In one example, a method may include rotating an adjusting camshaft of the valve lift control device in order to adjust a valve lift of one or more cylinders.

The present disclosure employs a pair of camshafts for intake valves. A first phase controller is installed at a first end of the first intake camshaft connecting to the crankshaft. A second phase controller is installed at a second end of the first intake camshaft connecting to the second intake camshaft. Each phase controller can adjust phase angle accordingly to modify intake valve timing and intake valve lift. This set up is duplicated for the exhaust valves to modulate exhaust valve timing and exhaust valve lift. First and second camshafts are connected via a series of levers, which merges the rotations of both camshafts into one. The phase controllers can be differential gear sets, epicyclical gear sets, or a combination thereof.

Aspects of the present disclosure are directed to an internal combustion engine having a valve actuation device and at least one first exhaust valve and one second exhaust valve per cylinder. The first and second exhaust valves may be actuated together in at least one operating area of the internal combustion engine, via an exhaust valve bridge and a first valve lifter, by a first cam lobe of a first exhaust cam arranged on a camshaft. The camshaft having a second exhaust cam with at least one additional cam lobe and at least one second cam lobe A transmission device being arranged in the functional path between the second exhaust cam and the second exhaust valve, the transmission device allowing an idle stroke to be activated or deactivated. The first exhaust cam and the second exhaust cam are configured and arranged to be rotatable relative to one another.

A valve assembly selectively varies the timing of the valves in an internal combustion engine cycle by way of a first and second camshaft. Each valve has a shuttle portion and a valve portion. Upper and lower cam followers on the shuttle portion engage with first and second cams on each of the first and second camshafts to move the valve between an open and closed position with reference to a valve seat on an engine block.

The present invention provides a camshaft capable of suppressing an increase in the number of parts and the number of places to be processed, preventing scratching on a sliding surface that is a part of an outer peripheral surface of an outer shaft and on which an inner cam is rotated, and preventing occurrence of deformation in the entire camshaft after final assembly. A camshaft includes an inner cam that is attached from a radial direction of an outer shaft and that is fixed to an inner shaft with a pin inserted into the inner cam from the radial direction of the outer shaft in a cam surface of the inner cam.

There is provided a variable valve device provided in a cylinder head and capable of changing a valve lift amount, including: a camshaft on which a plurality of cams with different valve lift amounts are formed; a switching mechanism configured to switch a cam for moving a valve among the plurality of cams; and an oil control valve configured to control an oil pressure for the switching mechanism. Oil starts to be supplied from the oil control valve to the switching mechanism at an end timing of a valve lift or in a zero range in which no valve lift occurs.

Provided is a four stroke internal combustion engine comprising at least one cylinder arrangement, a crankshaft, a camshaft, and a turbine. The camshaft is synchronized with the crankshaft to rotate at a same rotational speed as the crankshaft. A linkage arrangement is configured to prevent the motion of the valve head every alternate rotation of the camshaft, such that the exhaust opening remains closed during a compression stroke of the piston. Also a method for controlling a four stroke internal combustion engine is disclosed.

The present disclosure relates to a variable valve drive for a lifting valve, in particular for a charge-exchange valve of an internal combustion engine, which is periodically movable between a closed position and an open position indirectly by way of a cam via a rocker lever. The variable valve drive includes a switchable rocker lever arrangement for the actuation of the lifting valve, having a transmission rocker lever and a valve rocker lever which are mounted pivotably on different rocker lever axles which are each parallel to the camshaft axis.