VALVETRAIN ASSEMBLY WITH DEACTIVATION
A deactivating hydraulic lash adjustment (HLA) assembly includes an outer body configured to be received within a cartridge for a valve train carrier, a plunger disposed at least partially within the outer body, the plunger including a hollowed inner area, and an inner body disposed at least partially within the outer body and at least partially within the hollowed inner area. The inner body includes a low pressure chamber defined therein, and a high pressure chamber is defined between the plunger and the inner body within the hollowed inner area. The plunger is movable relative to the outer body and the inner body.
1 . A deactivating hydraulic lash adjustment (HLA) assembly comprising:
an outer body configured to be received within a cartridge for a valve train carrier;
a plunger disposed at least partially within the outer body, the plunger including a hollowed inner area; and
an inner body disposed at least partially within the outer body and at least partially within the hollowed inner area, the inner body having a low pressure chamber defined therein, wherein a high pressure chamber is defined between the plunger and the inner body within the hollowed inner area, wherein the plunger is movable relative to the outer body and the inner body based on a volume of hydraulic fluid provided in the high pressure chamber.
2 . The HLA assembly of claim 1 , further comprising a lost motion biasing mechanism disposed at least partially within the outer body, the lost motion biasing mechanism configured to selectively absorb motion transferred to the HLA assembly by a rocker arm assembly.
3 . The HLA assembly of claim 2 , wherein the lost motion biasing mechanism is disposed in an upper chamber defined in the outer body.
4 . The HLA assembly of claim 3 , further comprising a seat and seal disposed in the upper chamber between the lost motion biasing mechanism and the outer body and between the lost motion biasing mechanism and the inner body.
5 . The HLA assembly of claim 4 , wherein the inner body is press fit into the seat and seal.
6 . The HLA assembly of claim 1 , wherein the outer body defines an upper chamber and a lower chamber connected by a passage, the plunger disposed at least partially within the lower passage, and the inner body disposed in the passage, the upper chamber, and the lower chamber.
7 . The HLA assembly of claim 6 , further comprising a seal disposed between the inner body and the outer body to fluidly seal the upper chamber from the lower chamber.
8 . The HLA assembly of claim 1 , wherein the outer body includes a groove configured to selectively receive a latch assembly such that the HLA assembly is moved between an activated position and a deactivated position, wherein in the activated position the latch assembly is received within the groove, and in the deactivated position the latch assembly is not disposed within the groove to enable upward motion of the outer body relative to the cartridge that absorbs motion from a rocker arm assembly.
9 . The HLA assembly of claim 1 , wherein an upper boundary of the high pressure chamber is defined by the outer body.
10 . The HLA assembly of claim 1 , wherein a leakdown surface is defined between the plunger and the outer body, the leakdown surface configured to receive a fluid from the high pressure chamber.
11 . The HLA assembly of claim 10 , wherein the leakdown surface is set via hard turning such that a grind relief is not required, thereby reducing a volume in the high pressure chamber.
12 . The HLA assembly of claim 1 , further comprising a retention clip disposed in the outer body, the retention clip configured to retain the plunger within the outer body.
13 . The HLA assembly of claim 1 , further comprising a plunger biasing mechanism seated within the hollowed inner area between the plunger and the inner body.
14 . The HLA assembly of claim 1 , further comprising a check ball assembly disposed within the hollowed inner area between the plunger and the inner body, the check ball assembly configured to selectively allow a hydraulic fluid to pass from the low pressure chamber to the high pressure chamber, but prevent the hydraulic fluid from passing from the high pressure chamber to the low pressure chamber.
15 . The HLA assembly of claim 1 , wherein a reserve ratio of volume between the low pressure chamber and the high pressure chamber is approximately 1.4:1.
16 . The HLA assembly of claim 1 , wherein the plunger includes a spigot having a generally hemispherical surface configured to engage a rocker arm assembly.
17 . The HLA assembly of claim 1 , further comprising a sleeve disposed within the low pressure chamber, the sleeve defining a fluid channel between the sleeve and a wall of the inner body, the fluid channel fluidly separate from the low pressure chamber.
18 . The HLA assembly of claim 17 , wherein the fluid channel extends vertically.
19 . The HLA assembly of claim 18 , further comprising a fluid feed port formed in the outer body, the fluid feed port configured to supply a hydraulic fluid upward through the fluid channel and into the low pressure chamber.
20 . The HLA assembly of claim 19 , further comprising a seat and seal disposed in the upper chamber between the outer body and the inner body, the seat and seal configured to at least partially seal the fluid feed port.
21 . The HLA assembly of claim 19 , wherein the sleeve further includes an inlet port fluidly connecting the fluid channel and the low pressure chamber.
22 . The HLA assembly of claim 21 , wherein the fluid feed port is located at a point lower than the inlet port.
23 . The HLA assembly of claim 22 , wherein the inlet port is disposed above the low pressure chamber such that fluid remains in the low pressure chamber when the flow of fluid ceases and is prevented from reverse flow back into the fluid channel and the fluid feed port.
24 . The HLA assembly of claim 3 , wherein a diameter of the lower chamber is approximately 21 mm.
25 . The HLA assembly of claim 1 , wherein a portion of the low pressure chamber is submerged within the high pressure chamber within the hollowed inner area.
26 . The HLA assembly of claim 1 , further comprising a spacer configured to be disposed between the outer body and the cartridge, the spacer facilitating providing spacing and/or an initial lash for the outer body.
27 . The HLA assembly of claim 26 , wherein the outer body includes an open second end having an outwardly extending flange on the perimeter thereof, the spacer disposed between the outwardly extending flange and an upper surface of an upper flange of the cartridge.
28 . The HLA assembly of claim 27 , wherein the upper surface of the upper flange functions as a stop to limit downward movement of the outer body within the cartridge.