Abstract:
Deactivation apparatus for selected cylinders of an engine include switching hydraulic lash adjusters or valve lifters forming part of a valve train for actuating engine valves of the selected cylinders and operable to actuate or release their respective valves in response to an oil pressure signal. A gallery carrying the lash adjusters includes oil passages fed by an engine pressure oil supply through a control valve to supply oil to switching portions of the lash adjusters. The control valve is operative to close or open communication of the oil supply with the lash adjusters and to relieve oil pressure in the passages when communication with the pressure oil supply is closed. Various bypass alternatives between the pressure oil supply and the oil passages carry oil to portions of the oil passages to purge air from the passages when the three-way valve exhaust port is open.
Abstract:
In a valve train of an internal combustion engine, which valve train comprises an elongate anti-rotation bridge (6) comprising receptions spaced behind one another for receiving valve tappets configured as roller tappets (4), one of which tappets is arranged in each reception and is directed with a tappet roller (3) toward a cam (2) of a camshaft (1), the roller tappet (4) of the invention comprises on an outer peripheral surface, raised tappet contours (10, 11) that engage into retention grooves of the bridge (6) within the reception.
Abstract:
A roller cam follower has a transverse bearing shaft that is restrained against substantial lateral motion in a follower body supporting the shaft which rotatably carries a cam follower roller. The follower roller is rotatably mounted in a recess between opposite sides of the body on the transverse bearing shaft, which is supported in shaft bores through the sides of the body. One or more retainers are pressed onto the shaft within the recess and are operatively engageable with the sides of the body to limit axial motion of the shaft in said shaft bores. Various embodiments of retainers are disclosed as are applications to various types of roller cam followers, such as valve lifters, finger followers and rocker arms.
Abstract:
A tappet comprises a foot having a convex cam contact surface and an axially extending hub, a tappet body having a lower body portion with a lower axial bore formed therein to receive the axially extended hub of the foot, and a bearing assembly positioned between the foot and the lower portion of the tappet body. The cam contact surface operates in a frictional relationship with a cam lobe of a rotating cam. The frictional relationship between the cam lobe and the cam contact surface of the foot induces the foot to rotate about the center line of the tappet. The bearing assembly operates to reduce friction as the foot independently rotates axially about a center line of the tappet body.
Abstract:
A tappet comprises a foot having a convex cam contact surface and an axially extending hub, a tappet body having a lower body portion with a lower axial bore formed therein to receive the axially extended hub of the foot, and a bearing assembly positioned between the foot and the lower portion of the tappet body. The cam contact surface operates in a frictional relationship with a cam lobe of a rotating cam. The frictional relationship between the cam lobe and the cam contact surface of the foot induces the foot to rotate about the center line of the tappet. The bearing assembly operates to reduce friction as the foot independently rotates axially about a center line of the tappet body.
Abstract:
A damping mechanism for a lost motion hydraulic actuator utilizes a thin edge orifice in cooperation with a communication passageway between the upper and lower chambers controls the damping of the upper piston on closure. The upper piston is operatively connected to the engine valve of an internal combustion engine. A communication port from the upper chamber to the communication passageway is closed off as the upper piston returns to its normal position forcing the flow of the hydraulic fluid through the thin edge orifice. In this manner the viscosity of the hydraulic fluid does not control the damping of the actuator and the noise factor is substantially reduced.
Abstract:
A reservoir height extender for a lash adjuster assembly (150) comprising an inverted hollow insert member (60) disposed in fluid reservoir chamber (42) within a plunger member (40) of assembly (150). Plunger member (40) is reciprocally moveable within a bore (38) of a body member (36) having a first fluid passageway (48) adapted to receive fluid from a fluid source and which communicates with a second fluid passageway (46) in plunger member (40) adapted to enable the fluid to flow into fluid reservoir chamber (42). Insert member (60) is displaced from a wall of plunger member (40) surrounding chamber (42) for a distance sufficient to provide a third fluid passageway (68) therebetween which communicates between passageway (46) and an opening (64) through insert member (60) that is higher than passageway (46) and which enables a substantial increase in the level of fluid within reservoir chamber (42).
Abstract:
A reaction member located above an angled rocker arm induces the latter to pivot once a telescopically extendible hydraulic tappet, under the influence of a cam, has lifted the rocker arm sufficiently to engage an apex thereof against the reaction member. The tappet includes a piston which defines therein a variable volume chamber into which hydraulic fluid may be readily introduced via a solenoid control valve, but only slowly discharged. The degree of extension of the tappet controls the valve lift induced by the rocker arm.
Abstract:
A hydraulic lash adjuster for valve gear of an internal combustion engine, the hydraulic lash adjuster being of the type which operates from oil received under pressure from a gallery provided in the engine lubricant supply system to compensate for lash in the valve train. The body of the lash adjuster has a movable plunger assembly provided therein including upper and lower plunger members each having a bore therein which define upper and lower fluid reservoirs, respectively. A one way check valve is located between the lash adjuster body and the lower plunger member. A thin walled, cup shaped metal separator is received in the lower end of the upper plunger member for fluidly isolating the fluid reservoirs. The separator member is held in place by a plurality of outwardly turned retaining tabs extending from the open end thereof which engage the upper end of the lower plunger member. Annular metering passages meter the pressurized engine oil for supplying fluid to the lower and upper fluid reservoirs. A passageway in the top end of the upper plunger member conveys fluid from the upper fluid reservoir to a reaction surface located on the upper plunger member.
Abstract:
A valve drive device for an internal combustion engine characterized in a movably pivoted rocker arm, at either a cam-contacting part or a valve stem-contacting part thereof, having installed therein a built-in oil pressure tappet for automatically absorbing a gap created at such contacting part. Between the oil pressure tappet and the cam or the valve stem, in contact with the oil pressure tappet, a movable plate is provided, having a curved surface where the movable plate and/or the oil pressure tappet contact each other, thereby lubricating the contacting part to prevent its abrasion.