Abstract:
This valve actuation mechanism (S) for an internal combustion engine (E) on an automotive vehicle comprising rockers (9) moved by a camshaft (2), each rocker (9) being adapted to exert a valve opening force (F9) on at least a portion of a valve actuation mechanism of each cylinder belonging to a housing (E1) of the engine (E), via an engine brake activation piston (95), housed in a bore (94) of the rocker (9), and movable with respect to the rocker (9) under action of a fluid pressure raise in a chamber (101) fluidly linked to the bore (96), from a first position, in which an engine brake function is deactivated, to a second position, in which a roller (93) of the rocker (9) reads at least one engine brake bump of a cam (22) of the camshaft (2) so as to perform the engine brake function, each rocker (9) comprising a discharge valve (99) movable in translation with respect to the rocker (9), adapted to reduce fluid pressure in the chamber (101), wherein the engine brake system (S) comprises, for each rocker (9), a stopper (13) fast with the housing (E1) and adapted to exert, on a portion (961) of the piston (95), a force (F13) for opening the discharge valve (99) when the activation piston (95) has to be moved from its second position to its first position.
Abstract:
A variable valve actuation apparatus for an internal combustion engine includes a first link arm which has a projected portion that is engageable with and disengageable from a guide rail, and which is displaceable in the axis direction of a camshaft, and a link shaft linked to the first link arm in such a manner as to allow rotation but constrain movement in the axis direction. When an electromagnetic solenoid is electrified, the first link arm rotates about the link shaft so that the projected portion engages with the guide rail. In association with the displacement of the link arms that occurs during the engagement, the state of motion of second rocker arms changes, so that the opening characteristic of valves provided for each cylinder is switched.
Abstract:
A variable valve actuation system is disclosed, in one form a rocker is disclosed coupled with a valve stem at one end and a cam follower at the other end. The rocker is operable to pivot about a fixed axis. The cam follower is operable to be pivotally coupled with the rocker at one end of the cam follower. The cam follower includes a lower roller and an upper roller at its other end, each operable to engage cam lobes on separate cam shafts. In one form the cam follower includes a lower roller operable to follow a cam lobe on a lower cam shaft and an upper roller operable to follow a cam lobe on an upper cam shaft. The upper cam shaft and the lower cam shaft can have variable lobes. A spring can be used to bias the cam follower on the rocker.
Abstract:
A locking mechanism for a plural rocker arm valve train assembly is provided. The locking mechanism is adapted for use with a camshaft having a plurality of different cam lobes having a plurality of different profiles, which result in variable valve displacement and duration. A plurality of rocker arms are located on a pivot shaft which runs parallel to the camshaft, each rocker arm having structures configured to be acted upon by respective lobes of the camshaft. An active rocker arm has structure configured to act upon an engine valve or valves. A movable locking element is fully enclosed by the rocker arms and is capable of selectively moving along the pivot shaft to allow the active rocker arm to selectively engage one or more of the other rocker arms for common pivoting, resulting in varied displacement of the engine valve or valves.
Abstract:
The present invention relates to a piston engine (1), particularly for a motor vehicle, having at least one cylinder (3) comprising at least two discharge valves (9, 10). A dual camshaft (13) may be provided for controlling the discharge valves (9, 10) for the targeted increase of the exhaust gas enthalpy content, having an interior shaft (14) comprising at least one first cam (16) for controlling the respective first discharge valve (9) and an exterior shaft (15) coaxial thereto and having at least one second cam (17) for controlling the respective second discharge valve (10). For this purpose the interior shaft (14) and the exterior shaft (15) can be pivotally adjusted relative to each other in order to change the discharge time frame of the discharge valves (9, 10).
Abstract:
The present invention relates to a method for reducing engine vibrations during engine braking with a malfunctioning engine brake, where said engine brake comprising means for altering a timing of at least one exhaust valve and means for varying an exhaust gas back pressure, comprising the steps of: detecting piston acceleration for each cylinder in the engine during the use of said engine brake, comparing said detected piston acceleration with a predetermined reference value, decreasing exhaust gas back pressure during engine braking if at least one piston is detected with a piston acceleration deviating more than a predefined amount from said predetermined reference value so that said piston acceleration will be falling within said predefined amount from said predetermined reference value.
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.