Deactivation hydraulic valve lifter having a pressurized oil groove

#The present invention relates to valve lifters for use with internal combustion engines. More particularly, to a hydraulically switchable lifter-based device, which accomplishes cylinder deactivation in push-rod engines, and most particularly to such a device having a pressurized oil groove or grooves for routing air away from the switching oil supply.

#Cylinder deactivation is the deactivation of the intake and/or exhaust valves of a cylinder or cylinders during at least a portion of the combustion process. Cylinder deactivation is a proven method, by which fuel economy can be improved. With fewer cylinders performing combustion, fuel efficiency is increased and the amount of pollutants emitted from the engine is reduced. A known method of providing cylinder deactivation in a push rod engine is by using a deactivation mechanism in the hydraulic valve lifter.

#Preferably, for optimum packaging, the deactivation mechanism in a push rod engine is contained within the general envelope of a conventional hydraulic valve lifter. Such a device disclosed in commonly assigned U.S. Pat. No. 6,513,470 and incorporated herein by reference. In such a device, hydraulically operated latch pins are used to decouple concentrically disposed members of the deactivation roller hydraulic valve lifter (DRHVL). When in the decoupled mode, reciprocating motion imparted on the DRHVL via the rotating camshaft is isolated from the associated push rod and rocker arm deactivating the associated engine valve and its related cylinder.

#These and other features and advantages of the invention will be more fully understood and appreciated from the following description of certain exemplary embodiments of the invention taken together with the accompanying drawings, in which:

#FIG. 1 is a sectioned, perspective view of the deactivation hydraulic valve lifter of the present invention;

#FIG. 2 is a partially sectioned view of one embodiment of the lifter body shown in FIG. 1, assembled in an engine block and with the lifter shown in the base circle cam position; and

#Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification's set out herein illustrate the preferred embodiments of the invention, in one form, and such exemplification's are not to be construed as limiting tie scope of the invention in any manner.

#Referring now to the drawings and particularly to FIG. 1, there is shown DRHVL 10 as disclosed in the referenced U.S. Pat. No. 6,513,470. DRHVL 10 includes roller 12, lifter body 14, deactivation pin assembly 16, plunger assembly 18, pin housing 20, pushrod seat assembly 22, spring seat 23, lost motion spring 24, and spring tower 26.

#Plunger assembly 18 is disposed concentrically within pin housing 20, which, in turn, is disposed concentrically within lifter body 14. Pushrod seat assembly 22 is disposed concentrically within pin housing 20 above plunger assembly 18 to receive pushrod 19. Roller 12 is associated with lifter body 14. Roller 12 rides on the cam of an internal combustion engine and is displaced thereby. Roller 12 translates the rotary motion of the cam to an axial motion of lifter body 14. Deactivation pin assembly 16 normally engages annular chamber 28 disposed in inner wall 29 of lifter body 14, thereby transferring the vertical reciprocation of lifter body 14 to pin housing 20 and, in turn, to plunger assembly 18 and pushrod seat assembly 22. In this engaged position, the vertical reciprocation of DRHVL 10 opens and closes a valve of the internal combustion engine.