Abstract:
A hydraulic valve lifter assembly including a lifter body and a cam follower. The cam follower is mounted to an end of the lifter body wherein the lifter body has a first diameter over a first body portion for engaging a wall of an engine bore. The lifter body also including a second diameter smaller than the first diameter over a second body portion supportive of the cam follower. The hydraulic valve lifter assembly further including a contiguous annular transitional chamfer between the first and second diameter portions of the lifter body.
Abstract:
The invention proposes a switching element (1) for a valve train of an internal combustion engine, particularly for valve deactivation, with a simple-to-implement measure for adjusting the coupling lash of its coupling means (8) in a receptacle (6) using two retaining rings (19, 20), one of which is stocked in a variety of thicknesses.
Abstract:
A switch element (1) is proposed for valve shut-off, fabricated as cam follower for a plunger rod valve drive of an internal combustion engine, having an outer part (2) and an inner element (4) axially movable in its bore (3) and with rotational security (15) relative to the guided inner element (4). The outer part (2), inside the bore (3), has an annular groove (6), and the inner element (4) has a radial bore (7) with two diametrically opposed pistons (8), which to couple the elements (2, 4) in their axially remote relative position achieved by a lost-motion spring (5) are displaceable towards the annular groove (6). On their cam-side under side, emanating from their radially outward, bulbous face, the pistons (8) segmentwise comprise a plane transverse surface as contact area for a facing under side (27) of the annular groove (6). The latter is intersected by two diametrically opposed oil ports (11) running offset 90° from the pistons (8) in circumferential direction. In addition, the outer part (2) has means (13) for rotationally secured guidance of the switch element (1) relative to a surrounding structure.
Abstract:
A switchable cam follower, comprising two relatively movable, e.g., telescopable, units which can be connected via a coupling which engages over a dividing face between the units such that there is a large valve stroke. It is possible to generate no valve stroke or a small valve stroke if the coupling does not engage. At least one spring, which can be loaded compressively or torsionally, acts as a lost motion spring between the units. A compression limiting device impedes movement of the lost motion spring to the blocked position. In an incorrect switching operation in which the coupled units move undesirably toward each other and in a sudden manner under the influence of a valve spring force, movement of the spring into the “blocked” position to become seated is prevented by the limiting device.
Abstract:
A hydraulic valve lifter including venting means to assure venting of air through the lifter and filling thereof with oil during pre-start filling of the engine oil galleries after engine assembly. Patterning of a hemispherical pushrod seat surface, and/or patterning of either or both of the mating surfaces of a pushrod seat and a piston, permits air purged from the engine through a pushrod to be vented through the lifter. Such means may be temporary or permanent and may include coatings of the surfaces with materials that are destroyed by engine action after starting. Permanent means may include surface grooves in the mating surfaces and/or small-diameter passages between the hemispherical seat surface and the cylindrical outer surface of the pushrod seat. Venting means in accordance with the invention is useful for both valve-deactivating and non-valve-deactivating valve lifters.
Abstract:
A hydraulic valve lifter assembly including a lifter body and a cam follower. The cam follower is mounted to an end of the lifter body wherein the lifter body has a first diameter over a first body portion for engaging a wall of an engine bore. The lifter body also including a second diameter smaller than the first diameter over a second body portion supportive of the cam follower. The hydraulic valve lifter assembly further including a contiguous annular transitional chamfer between the first and second diameter portions of the lifter body.
Abstract:
A switchable cam follower, comprising two relatively movable, e.g., telescopable, units which can be connected via a coupling which engages over a dividing face between the units such that there is a large valve stroke. It is possible to generate no valve stroke or a small valve stroke if the coupling does not engage. At least one spring, which can be loaded compressively or torsionally, acts as a lost motion spring between the units. A compression limiting device impedes movement of the lost motion spring to the blocked position. In an incorrect switching operation in which the coupled units move undesirably toward each other and in a sudden manner under the influence of a valve spring force, movement of the spring into the “blocked” position to become seated is prevented by the limiting device.
Abstract:
A switch element (1) is proposed for valve shut-off, fabricated as cam follower for a plunger rod valve drive of an internal combustion engine, having an outer part (2) and an inner element (4) axially movable in its bore (3) and with rotational security (15) relative to the guided inner element (4). The outer part (2), inside the bore (3), has an annular groove (6), and the inner element (4) has a radial bore (7) with two diametrically opposed pistons (8), which to couple the elements (2, 4) in their axially remote relative position achieved by a lost-motion spring (5) are displaceable towards the annular groove (6). On their cam-side under side, emanating from their radially outward, bulbous face, the pistons (8) segmentwise comprise a plane transverse surface as contact area for a facing under side (27) of the annular groove (6). The latter is intersected by two diametrically opposed oil ports (11) running offset 90° from the pistons (8) in circumferential direction. In addition, the outer part (2) has means (13) for rotationally secured guidance of the switch element (1) relative to a surrounding structure.
Abstract:
A lifter assembly for an internal combustion engine, including an elongate sleeve having an upper radial wall portion provided with oil feed and oil bleed holes through which oil respectively enters and exits the lifter assembly. An elongate, hollow lifter body closed at one end is reciprocatingly disposed within the sleeve, and has a plunger reciprocatingly disposed therein. The plunger has an internal cavity at least partially defining a low pressure oil reservoir which is in at least periodic fluid communication with the oil feed hole. A high pressure oil reservoir is at least partially defined by the plunger and the lifter body closed end, and is in one-way fluid communication with the low pressure oil reservoir. A cap is reciprocatingly disposed within the sleeve and engaged with the plunger. Seals are provided which preclude oil from exiting the lifter assembly through the ends of the sleeve.
Abstract:
Hydraulic engine valve lifter includes a pair of pistons defining a pressure chamber therebetween and a separate lash adjusting piston which defines a lash adjustment chamber with one of the pistons in the pair. One-way valve structures permit fluid to flow from the pressure chamber into the lash adjustment chamber thereby displacing the lash adjusting piston to, in turn, adjust valve lash. Motion damping functions during a downstroke of the lifter pistons are also provided by a valve damper chamber and fluid passageways between the pressure and damper chambers. Structure is provided which opens communication between the pressure and damper chambers during upstroke of the lifter pistons (thereby precluding motion damping) and then closes communication at a predetermined location during downstroke (thereby providing motion damping).