Abstract: An improved deactivation hydraulic lash adjuster wherein the prior art lost motion spring or springs formerly located within the body of the DHLA and below the pin housing are either omitted completely or are reduced in length, spring force, and/or number and are augmented hydraulically, allowing a shorter, more compact lifter body and reduced overall lifter length. The prior art lost motion spring chamber becomes a hydraulic chamber connected to a new pressurized oil supply gallery containing an accumulator in the engine. An embodiment having no lost motion spring and solely hydraulic lost motion return can be even shorter than a spring-hydraulic hybrid because the potential hydraulic pressure to be brought against the pin housing is not a function of the length of the lost motion chamber, which length is limited only by the required displacement of the pin housing.

Abstract: A DHLA including a hydraulic lash adjustment mechanism disposed within a plunger slidably disposed within a pin housing that is slidably disposed within an axial bore in an adjuster body. A lash ring disposed in a groove near the outer end of the DHLA body includes a portion extending into the bore to limit travel of the pin housing and thereby set the internal mechanical lash in the DHLA. The lash ring has a thickness selected to provided a predetermined amount of mechanical lash in the assembled lifter, which thickness varies from assembly to assembly to compensate for manufacturing variation in the components. A biasing means such as a wave ring, a Belleville washer or a beveled retaining ring is also installed in the annular groove to urge the lash ring against the lower surface of the groove under all DHLA operating conditions.

Abstract: A deactivating hydraulic lash adjuster comprising a pin housing slidably disposed in a body and having at least one lock pin disposed in a transverse bore for extending into a receiver feature in the body to lock the two together during periods of engine operation in valve non-deactivation mode. The present improvement consists in providing a first orienting feature for the lash adjuster body that engages a second orienting feature on an engine head to provide a preferred and fixed orientation of the body within a bore in the engine head. In a currently preferred orientation, the axis of the at least one lock pin is parallel to the axis of the engine camshaft. The orientation of the lock pin(s) to the body is made invariant by insertion of a pin through a radial bore in the body into a longitudinal groove in the pin housing.

Abstract: A DHLA including a hydraulic lash adjustment mechanism disposed within a plunger slidably disposed within a pin housing that is slidably disposed within an axial bore in an adjuster body. A lash ring disposed in a groove near the outer end of the DHLA body includes a portion extending into the bore to limit travel of the pin housing and thereby set the internal mechanical lash in the DHLA. The lash ring has a thickness selected to provided a predetermined amount of mechanical lash in the assembled lifter, which thickness varies from assembly to assembly to compensate for manufacturing variation in the components. A biasing means such as a wave ring, a Belleville washer or a beveled retaining ring is also installed in the annular groove to urge the lash ring against the lower surface of the groove under all DHLA operating conditions.

Abstract: An improved deactivation hydraulic lash adjuster wherein the prior art lost motion spring or springs formerly located within the body of the DHLA and below the pin housing are either omitted completely or are reduced in length, spring force, and/or number and are augmented hydraulically, allowing a shorter, more compact lifter body and reduced overall lifter length. The prior art lost motion spring chamber becomes a hydraulic chamber connected to a new pressurized oil supply gallery containing an accumulator in the engine. An embodiment having no lost motion spring and solely hydraulic lost motion return can be even shorter than a spring-hydraulic hybrid because the potential hydraulic pressure to be brought against the pin housing is not a function of the length of the lost motion chamber, which length is limited only by the required displacement of the pin housing.

Abstract: A roller finger follower assembly for variably activating a valve in an internal combustion engine includes at least one vertical recessed channel formed inside an outer arm and a shaft. The channel includes a machined upper surface closing the channel. The shaft engages with the recessed channel, the shaft reciprocates within the recessed channel, and the upper surface stops an upward movement of the shaft.

Abstract: A deactivation valve lifter includes a lifter body. The lifter body has a first end configured for engaging a cam of an engine and at least one annular pin chamber. A pin housing includes a pin housing bottom. The pin housing bottom defines at least one pin stop aperture and a radially directed pin bore. A deactivation pin assembly is disposed within the pin bore and includes pin members. The pin housing is concentrically disposed within the lifter body. A portion of each pin member may be disposed within the annular pin chamber to thereby selectively couple and decouple the lifter body to the pin housing. A drain aperture defined by the pin housing bottom extends from the pin bore to an outside surface of the pin housing. A stop pin is disposed in the at least one pin stop aperture for limiting the inward motion of the pin members.

Abstract: A switchable valve train member, such as a deactivating valve lash adjuster or a deactivating hydraulic valve lifter, including a pin housing slidably disposed within an axial bore in a body. A transverse bore in the pin housing contains a retractable locking pin that engages a feature in the body including a locking surface whereby the body and the pin housing are locked together for mutual actuation by rotation of a cam lobe. A lash ring at the outer end of the body includes a portion extending into the axial bore that limits the travel of the pin housing within the body and thereby sets the internal mechanical lash in the switchable member. The axial thickness of the lash ring may be varied between assemblies to compensate for manufacturing variation in the components and is secured to the body in any of various configurations.

Abstract: A valve lifter assembly for deactivating a cylinder in an internal combustion engine. The valve lifter assembly is provided with a plunger movably disposed within a bore of a main body member to controllably isolate the cam lift from the rocker arm and valve of the engine. The plunger is normally locked in an extended position to transmit cam lift to reciprocatingly operate the valve. At least one locking pin is moveably disposed within the plunger to engage an inner annular groove of the main body member. Pressurized oil is provided to dislodge the locking pins from the annular groove and allow the plunger to move within the main body member, thereby isolating the cam lift from the rocker arm and valve. The deactivating lifter is preferably disposed within the recess conventionally provided for hydraulic valve lifters.

Abstract: A switchable valve train device including a pin housing slidably disposed in a body and having a transverse bore. A stepped plug in the transverse bore extends beyond the pin housing to engage a slot in the body to prevent rotation of the pin housing. The upper end of the slot limits travel of the pin housing. The plug is a seat for a compression spring. A locking pin is disposed in the transverse bore against the spring to selectively engage a locking port in the body, the locking pin and the locking port have mating flats to distribute the load. Mechanical lash is set by use of a gage tool during assembly, allowing selection of a locking pin of appropriate thickness. The device may be, for example, a switchable hydraulic lash adjuster or a switchable valve lifter.

Abstract: A two-step roller finger follower having a high-lift follower portion that pivots on a pivot shaft disposed on a low-lift follower portion, and having a lost-motion spring disposed between the high-lift follower and the low-lift follower to bias the high-lift follower toward the high lift cam lobe. Various bearing cups and roller shaft sleeve embodiments are shown, all of which allow for improved shaft and needle bearing arrangements. A z-stop formed by the bearing cups and/or the shaft sleeve limits the range of travel of the high-lift follower with respect to the low-lift follower. Various z-stop embodiments are provided including a non-contacting roller shaft sleeve that grounds the high-lift follower to the low-lift follower independent of the roller shaft.

Abstract: A roller finger follower assembly for variably activating a valve in an internal combustion engine includes at least one vertical recessed channel formed inside an outer arm and a shaft. The channel includes a machined upper surface closing the channel. The shaft engages with the recessed channel, the shaft reciprocates within the recessed channel, and the upper surface stops an upward movement of the shaft.

Abstract: In an engine valve train equipped with a DHLA, the radius of the base circle of a cam lobe is decreased, relative to the radius of the base circle of a cam lobe in an engine equipped with an HLA, in proportion to the internal lash in the DHLA. The actual decrease in the base-circle radius is calculated by trigonometric relationships among the base circle portion, the length of the rocker pivot arm, and the internal lash of the DHLA. The decrease in the base circle radius is compensated by extension of the valve train lash-adjustment mechanism of the DHLA. After the internal DHLA lash is taken up during valve actuation, the coordinate position of the pivot point of the DHLA rocker arm is then identical with the coordinate position of the pivot point of an HLA rocker arm of a DHLA-equipped engine.

Abstract: A switchable valve train member, such as a deactivating valve lash adjuster or a deactivating hydraulic valve lifter, including a pin housing slidably disposed within an axial bore in a body. A transverse bore in the pin housing contains a retractable locking pin that engages a feature in the body including a locking surface whereby the body and the pin housing are locked together for mutual actuation by rotation of a cam lobe. A lash ring at the outer end of the body includes a portion extending into the axial bore that limits the travel of the pin housing within the body and thereby sets the internal mechanical lash in the switchable member. The axial thickness of the lash ring may be varied between assemblies to compensate for manufacturing variation in the components and is secured to the body in any of various configurations.

Abstract: A deactivating hydraulic lash adjuster comprising a pin housing slidably disposed in a body and having at least one lock pin disposed in a transverse bore for extending into a receiver feature in the body to lock the two together during periods of engine operation in valve non-deactivation mode. The present improvement consists in providing a first orienting feature for the lash adjuster body that engages a second orienting feature on an engine head to provide a preferred and fixed orientation of the body within a bore in the engine head. In a currently preferred orientation, the axis of the at least one lock pin is parallel to the axis of the engine camshaft. The orientation of the lock pin(s) to the body is made invariant by insertion of a pin through a radial bore in the body into a longitudinal groove in the pin housing.

Abstract: A method for detecting failure modes of latching mechanisms in a hydraulically switchable variable valve activation system of an internal combustion engine includes the steps of: integrating a pressure sensor in an engine control system including a plurality of switchable mechanisms connected to a common hydraulic gallery, an oil control valve downstream of the oil gallery, and en engine controller activating the oil control valve and the pressure sensor; measuring fluid pressure of the gallery with the pressure sensor; and determining if a failure mode of latching mechanisms occurred by evaluating the measured fluid pressure. Sudden flow changes that produce high frequency fluid pressure oscillations in the oil gallery are detected with the pressure sensor and evaluated by an engine controller to detect lock pin failure modes, such as lock pin ejections and operation of two-step RFF in a low lift mode at elevated engine speeds.

Abstract: A latching mechanism for variably activating an engine valve in an internal combustion engine includes a rocker arm body having a bore and a socket. A first passage leads from the socket to a first hydraulic chamber formed above a lock pin head. A second passage leads from the socket to a second hydraulic chamber formed below the lock pin head. Since both the first and the second hydraulic chamber receive pressurized oil, it is the diameter of the pin shank that determines the hydraulic force needed to axially move the locking pin to an extended position and into a locking engagement with a slider member. In an alternate embodiment of the invention the first passage connecting the first hydraulic chamber with the socket is eliminated and instead the locking pin is modified to permit flow between second hydraulic chamber and first hydraulic chamber.

Abstract: A deactivation valve lifter includes a lifter body. The lifter body has a first end configured for engaging a cam of an engine and at least one annular pin chamber. A pin housing includes a pin housing bottom. The pin housing bottom defines at least one pin stop aperture and a radially directed pin bore. A deactivation pin assembly is disposed within the pin bore and includes pin members. The pin housing is concentrically disposed within the lifter body. A portion of each pin member may be disposed within the annular pin chamber to thereby selectively couple and decouple the lifter body to the pin housing. A drain aperture defined by the pin housing bottom extends from the pin bore to an outside surface of the pin housing. A stop pin is disposed in the at least one pin stop aperture for limiting the inward motion of the pin members.

Abstract: An oil distribution system for an internal combustion engine comprising a longitudinal bore in the engine head or block connected to an engine oil pump. A longitudinal insert is disposed in the engine bore, the insert being formed and disposed to define segmented galleries within the bore, a first oil gallery being in communication with the engine camshaft bearings and a second oil gallery being in communication with switchable cam followers in the engine. The two galleries are separated but connected by one or more oil control valves. Thus, the camshaft bearings are exposed to high engine oil pressure at all times independent of the switchable cam followers; likewise, the switchable cam followers may be latched and unlatched at any time or condition deemed beneficial for engine operation without jeopardizing lubrication sufficiency to the camshaft bearings.

Abstract: A two-step roller finger follower assembly for shifting between high-lift and low-lift valve modes in a valve train of an internal combustion engine includes a body having side members defining coaxially disposed shaft orifices, a pallet end, a socket end, a slider arm aperture, and a latch pin channel. The socket end is mountable to a hydraulic lash adjuster, and the pallet end is matable with a valve stem. A slider arm for engaging a high-lift cam lobe is disposed in the aperture, is pivotably mounted to a rotatable cross-shaft extending through the shaft orifices, and includes a slider tip for selectively engaging a latch pin to latch or unlatch the slider arm from the body. Dual rollers on the cross-shaft follow dual low-lift cam lobes. Preferably, the slider arm has a compound radial surface to provide compound lost motion of the slider arm, thereby minimizing rotational inertia.