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 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:
Valve lift variation associated with a deactivation roller hydraulic valve DRVHL (DRHVL) can result in unacceptable valve overlap and idle conditions for an internal combustion engine. Two sources of length variation in a DRHVL are leakdown and residual mechanical lash. Total length variation is the sum of these two factors, and each factor has an associated tolerance. In the prior art, the two factors are independent, resulting in a total population variation that is the sum of the two independent variations. A DRHVL assembly process in accordance with the invention includes the step of associating leakdown test results for individual lash adjusters with residual lash results by adjusting the residual lash characteristics of individual DRHVL assemblies to complement the leakdown characteristics in minimizing total length variation in the population of assembled DRHVLs.
Abstract:
A method for distributing lock pin ejections evenly over all the switchable mechanisms in a plurality of switchable mechanisms: establishing a limiting number of lock pin ejections; designating a primary switchable mechanism for the mode change upon command from an engine control module (ECM); employing the designated primary switchable mechanism until the limit is reached; designating another switchable mechanism a primary; employing the second primary mechanism until the limit is reached again; and designating sequentially each of the remaining switchable mechanisms as primary switchable mechanisms, each until the limit is reached again. The ECM counts the activation commands and switches the primary designation when the limit is reached so that each mechanism has the same exposure to ejections, and the number of ejections per mechanism is evenly distributed. If ejection detection means is available, the ECM may accumulate actual ejections for each mechanism and schedule the primary designation change thereupon.
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 control system for variable activation of valves in an internal combustion engine. A solenoid is disposed on the outer surface of the valve cam cover to avoid exposure to the hot-oil environment within the valve activation chamber. The solenoid armature extends through the cam cover into the valve activation chamber. A bellcrank is mounted between the solenoid armature and the latching pin of a latchable cam finger follower such that energizing and de-energizing of the solenoid causes corresponding actuation and deactuation of the finger follower, which may be suitable for high-lift and low-lift activation. Preferably, the bellcrank is compliant such that when the solenoid is actuated during the lift portion of the valve cycle the pin is placed under compression so that the pin is subsequently actuated into latching position when the follower moves to the base circle portion of the valve cam. Preferably, for a plurality of such systems on an individual engine, the solenoids are provided with connecting pins on an upper surface thereof and are held in place by a retainer containing an overmolded wiring bundle which automatically connects correctly to each solenoid upon installation of the retainer onto the engine.
Abstract:
A mechanical assist actuation bracket for use with a roller finger follower. The roller finger follower includes a locking pin assembly having a trigger pin. The mechanical assist actuation bracket includes a face configured for being affixed to the roller finger follower. An arm extends from the face. The arm is configured for translating an actuating arm of an actuating device associated with the roller finger follower in a direction toward and away from the trigger pin during pivotal movement of the roller finger follower.
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 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:
An internal combustion engine is equipped to supply the camshaft bearings with pressurized oil via a first dedicated oil gallery independently of the hydraulic lash adjusters (HLAs) and any valve deactivation devices which are supplied from a second dedicated oil gallery. The galleries may be connected at their downstream ends and a flow restriction is placed in a connecting passage or within each HLA. An improved HLA is similar to a prior art HLA except that the prior art annular oil distribution groove in the outer surface of the HLA body is eliminated to prevent communication of the primary engine oil gallery with the HLA. The secondary gallery is formed remotely from the first oil gallery in the HLA residence bore in the engine, and the HLA is prevented from rotating within the residence bore.