KR20010089206A - Valve deactivator assembly for internal combustion engine - Google Patents

Abstract

PURPOSE: A valve deactivator assembly of an internal combustion engine is provided to apply to a valve gear train of an end pivot rocker arm shape and to control a hydraulic lash adjuster. CONSTITUTION: A valve deactivator assembly is composed of a rocker arm(33) having a pivot location about the rocker arm normally pivots in response to rotation of the cam shaft(25). The valve deactivator assembly has a HLA(Hydraulic Lash Adjuster(41) serving as the pivot point for the rocker arm. The HLA includes a body and a plunger assembly, including a plunger portion having an engagement portion surrounding the plunger portion and in engagement with the pivot portion of the rocker arm. A latch mechanism is operable to either latch the engagement portion, for operation in a deactivated mode. Thus, the latch mechanism does not add to the overall size of the main part of the HLA, or of a bore in a cylinder head(11).

Description

VALVE DEACTIVATOR ASSEMBLY FOR INTERNAL COMBUSTION ENGINE}

The present invention relates to an improved valve train for use in an internal combustion engine, and more particularly to a valve deactivator assembly for use in an internal combustion engine.

Although the valve deactivator assembly of the present invention can be used to induce some additional lash into the valve train so that the valve opens and closes less than the amount of normal valve opening / closing, the present invention provides a sufficient lash for the valve train In particular, it is particularly suitable for inducing " lostmotion " so that the valve can no longer be opened (ie, the valve is deactivated). And the present invention will be described in connection with this feature.

Valve deactivators of the general type related to the present invention are known in connection with various internal combustion engine valve gear trains, including push-rod type overhead valve (OHV) gear trains. Valve deactivators are also known in connection with an overhead cam (OHC) type valve gear train of center pivot rocker arm type and end pivot rocker arm type. Although the specific structure of the present invention is not limited to the overhead cam type valve gear train of the end pivot rocker arm type, it is particularly suitable for this gear train and will be described in connection with this type of gear train.

A typical end pivot rocker arm valve gear train has a rocker arm that rotates about a pivot defined by the rocker arm. This pivot engages with a ball plunger of a hydraulic lash adjuster (HLA), where the hydraulic lash adjuster is installed in the bore of the cylinder head. Hydraulic lash regulators that impose a kind of valve deactivation capability are known in the art. In this application, there is sufficient space in the cylinder head to replace the hydraulic lash regulator with valve deactivation capability, which eventually takes up more space than conventional hydraulic lash regulators.

Unfortunately, many automotive installations that require valve deactivation capabilities do not even have enough space for conventional hydraulic lash regulators. Therefore, not to mention the larger hydraulic lash regulator with the added structure. The structure added here is a typical latch and lost motion mechanism. For example, such a mechanism causes the plunger assembly of the hydraulic lash regulator to be locked to the body in normal operation, or unlocked for operation in the valve deactivation mode to engage in lost motion. Such added structure will substantially increase the size and complexity and manufacturing costs of conventional hydraulic lash regulators.

For example, in a latching type valve deactivator disclosed in US Pat. No. 5,655,487, the latching mechanism includes latch elements, which latch or unlock the body and plunger assembly. To radially move under the action of a spring or hydraulic force. It is clear that the overall diameter of such a valve deactivator is much larger than conventional hydraulic lash regulators (conventional hydraulic lash regulators only require conventional wall thicknesses used for bodies and plungers). In addition, since the plunger must be made movable between the locked position and the unlocked position relative to the body, the total depth required for the bore of the cylinder head including the hydraulic lash adjuster is long.

It is therefore an object of the present invention to provide a valve deactivator assembly which has the feature of not increasing the overall size of the hydraulic lash regulator by adding the deactivation function and which is particularly suitable for the valve gear train of the end pivot rocker arm type.

In addition to achieving the above object, it is another object of the present invention to provide an improved valve deactivator assembly that does not require larger than the bore required for a cylinder head to accommodate a conventional hydraulic lash regulator.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a somewhat schematic cross-sectional view of a portion of an internal combustion engine cut out to illustrate a typical valve gear train in which the invention is used;

FIG. 2 is an enlarged fragmentary sectional view taken along line 2-2 of FIG. 1 to illustrate the valve deactivator assembly of the present invention in standard, locked conditions; FIG.

FIG. 3 is a perspective view of a portion similar to FIG. 1 to illustrate the valve deactivator assembly and valve gear train of the present invention in unlocked condition; FIG. And

FIG. 4 is an enlarged partial cross-sectional view similar to FIG. 2 to illustrate the valve deactivator assembly of the present invention in a locked condition in more detail.

* Explanation of symbols for main parts of the drawings

17: engine poppet valve

25: camshaft

29: base circle portion

31: lift portion

37: cam follower

33: rocker arm

39: pivot

40: sidewall

11c: oil passage

57p, 75: axial extension passage

43: Valve Deactivator Assembly

49: cylindrical body

53: Plunger Assembly

71: Lost Motion Spring

79 radially extending bore

87: latch pin

91: piston

The above and other objects of the present invention are achieved by providing a valve deactivator assembly for an internal combustion engine configured as described below. The valve deactivator assembly comprises valve means for controlling the flow into or out of the combustion chamber, drive means for providing periodic movement to open and close the valve means in time with a stroke in the combustion chamber, and periodic movement It is provided with a valve gear means for operating in accordance with the periodic opening and closing of the valve. The valve gear means comprises a rocker arm having a valve contact engaged with the valve means and a pivot which is the center at which the rocker arm normally rotates in response to the periodic movement of the drive means. And the valve deactivator assembly includes a hydraulic lash adjuster that adapts to the cylinder head and acts as a pivot point for the pivot position of the rocker arm.

The hydraulic lash adjuster is characterized by a body member disposed in the orifice and a plunger assembly that can reciprocate relative to the body member. The plunger assembly includes a plunger portion and an engagement portion surrounding the plunger portion and engaging the pivot position of the rocker arm. The latch mechanism lockably engages the engagement portion with respect to the plunger portion in an extended posture while operating in normal mode, so as to unlock the engagement portion with respect to the plunger portion while operating in deactivated mode. Works. The lash adjuster has means for biasing the engagement towards the extended posture.

Although not intended to limit the invention, and now with reference to the drawings, FIG. 1 shows a valve for driving a drive train of an end pivot rocker arm type, which is particularly suitable for application of the invention. 1 shows a cylinder head 11 defining a flow passage 13 by which flow can be formed which flows into or out of the combustion chamber 15.

The flow into or out of the combustion chamber 15 is regulated by the engine poppet valve 17, as shown in FIG. 1, which is biased by the valve spring 19 to the closed position. Poppet valve 17 includes a valve seat 21, which is a valve seat insert (not shown but known in the art) when poppet valve 17 is closed. )

The cam shaft 25 includes a cam profile 27, which cam profile defines a base circle portion 29 and a lift portion 31. As is well known to those skilled in the art, the function of the camshaft 25 is to provide periodic movement to open and close the poppet valve 17 in time with the stroke of the combustion chamber 15.

The periodic movement of the camshaft 25 is transmitted to the engine poppet valve 17 by the rocker arm 33 and is described herein as being of end pivot type. This operation can be seen by comparing FIG. 1 and FIG. 3, in which the rocker arm 33 is shown through a cross section through the rocker arm. The rocker arm 33 includes a valve contact (pad) 35 in contact with the top of the stem of the poppet valve 17. The rocker arm also includes a rotatable cam follower 37, which is mounted above the shaft 38, with the rocker arm 33 always in contact with the cam contour 27. maintain. Finally, the rocker arm 33 includes a pivot 39, which defines the pivot position. When the cam follower 37 alternately contacts the base circle portion 29 and the lift portion 31, the rocker arm 33 generally rotates around this pivot position. As an accessory embodiment or only as an example, the pivot 39 consists of a rocker arm 33 having a pair of side walls 40. As best seen in FIG. 2, the side walls 40 here each comprise a semicircular support surface 40s. Coupled with the support surface 40s of the pivot 39 is the hydraulic lash adjuster (HLA) 41 shown in FIGS. 1, 2 and 3.

Referring now primarily to FIG. 2, it can be seen that the rocker arm 33 and the hydraulic lash regulator 41 make up the valve deactivator assembly 43. A bore 45 is formed in the cylinder head 11, which is elongated to the upper surface of the cylinder head 11. And an oil passage 47 is formed in the cylinder head 11, which is usually connected to the circulation system of the engine lubricating oil. As is well known in the general manner to those skilled in the art of hydraulic lash regulators, the oil passage 47 constitutes one "pressure fluid source" needed to drive the hydraulic lash regulator 41.

The hydraulic lash adjuster 41 usually includes a cylindrical body 49 disposed within the bore 45. The cylindrical body 49 is formed with a blind bore 51 therein. The plunger assembly 53 is arranged to slide in the blind bore 51. And the plunger assembly includes an upper plunger element 55 and a lower plunger element 57 and a leakdown plunger 58. These plunger elements 55, 57, 58 together form a low pressure chamber 59 (also referred to hereafter as a reservoir). The blind bore 51 and the leakdown plunger 58 together comprise a high pressure chamber, which simply comprises the reference numeral '51', in which the high pressure chamber is under approximately minimum volume conditions. Is showing.

The check valve assembly 61 is driven to permit fluid to be transferred between the reservoir 59 and the high pressure chamber 51, which is usually performed in a manner well known to those skilled in the art. Although the present invention has been described in connection with a leakdown type hydraulic lash regulator commonly used, it will be understood that the present invention is not necessarily so limited and may be applied to many other types of hydraulic lash regulators. And while the present invention has been described in connection with a hydraulic lash adjuster of the type having a movable plunger assembly positioned within a stationary body member, it should be understood that this is not limitative. For example, the movable plunger assembly may enclose a stationary body member within the technical scope of the present invention. It is essential to the present invention that there is a plunger assembly having a body member and capable of relative (round trip) movement with respect to the body member.

Referring primarily to FIG. 2, a fluid port 63 is formed in the cylindrical body 49, which is openly connected to the oil passage 47 to allow fluid to flow. A radial bore 65 is formed in the upper plunger element 55, which is openly connected to the fluid port 63 so that the pressure fluid is connected to the oil passage 47, the fluid port 63. And radial bore 65. An axially extending passage 66p is formed in the lower plunger element 57, with the upper end of the axially extending passageway through the port 66 near the upper end of the lower plunger member 57. Low pressure fluid in 47 flows through the axially extending passageway 66p and enters the low pressure chamber 59 through the port 66.

An oil passage 11c located on the left side of FIG. 2 showing the hydraulic lash regulator 41 is formed in the cylinder head 11, which is an engine oil circulation system (circulation system connected with the oil passage 47). Fluid is circulated. The oil passage 11c constitutes a pressure fluid source necessary to (drive) control the valve deactivator assembly 43 of the present invention. Therefore, it must be able to control the oil pressure of the oil passage 11c. Such control is to provide relatively low or high pressure selectively, such methods being well known to those skilled in the art of engine oil pressure. As an example only, the pressure in the oil passage 11c may be controlled by a solenoid valve (not shown here). A hole is formed in the cylindrical body 49, and a cylindrical member 49m having a roll pin or similar structure is located in the hole. The cylindrical member 49m extends radially inwardly enough into the hole 55o formed in the upper plunger element 55, whereby the upper plunger element 55 is substantially in relation to the cylindrical body 49. Relative rotation is prevented. Another axially extending passage 57p is formed in the lower plunger element 57, through which the control pressure of the oil passage 11c causes the cylindrical member 49m, the hole 55o and the axially extending passage 57p. Can flow through. The reason for this will be explained later.

Looking at a conventional hydraulic lash adjuster, the upper plunger element 55 has a ball plunger portion that engages with an adjacent surface of the rocker arm. According to one important aspect of the invention, the upper plunger element 55 comprises a separating plunger portion 67 (pointing to the top of the upper plunger element) and an engagement portion 69. Here, the coupling portion 69 surrounds the cylindrical separation plunger portion 67 and is installed to be able to move (vertical direction in FIG. 2) with respect to the separation plunger portion 67. The compression (lost motion) spring 71 surrounds the lower part of the separating plunger portion 67 and is operated to bias the coupling portion 69 upwards, and when extended to the end, it has a shape as shown in FIG. 2. .

In the extended position described above in FIGS. 2 and 4, the engaging portion 69 is engaged with and biased with a snap ring (retaining clip) 72 which limits its upward movement. Engagement 69 engages pivot 39, which does not allow any vertical movement of pivot 39 when the valve deactivator assembly is in operating (latch) mode. This is then explained in more detail. When the sliding engagement 69 engages the snap ring 72, some of the force exerted by the lost motion spring 71 is transmitted directly to the snap ring 72. That is, not all forces of the lost motion spring 71 act on the rocker arm 33. Instead, the force transmitted to the rocker arm 33 is approximately equal to the force exerted on the upper plunger element 55 by the pressure of the high pressure chamber 51.

Referring now primarily to FIG. 4, an axially extending passage 75 is formed in the upper plunger element 55, which is openly connected to the radially extending bore 79, although the end thereof is blocked. have. Enclosing the separating plunger portion 67 is generally a block portion of the engagement portion 69 (as shown in FIG. 3), and extending from the block portion to the opposite side is a pair of cylindrical latch housing portions 81. These latch housing portions 81 together serve as lever support of the semicircular support surfaces 40s of the rocker arm 33 as well shown in FIG. 2. The latch housing portions 81 are each formed with radially extending bores 83, which are radially extending bores when the engaging portion 69 is in the extended position as shown in FIGS. 2 and 4. 79). The radially extending bores 83 are each closed by their plugs 85 with their radially outer ends. A latch pin 87 is arranged in the radially extending bore 83 to reciprocate therein, which is biased toward the latch position shown in FIG. 4 by the compression (latch) spring 89. Lose. And, the radially outer portion of the latch spring 89 is mounted against each plug 85.

A pair of pistons 91 are arranged in radially extending bores 79, in the latched position shown in FIG. 4, these pistons radially inward by the latch pins 87 under the influence of the latch spring 89 to engage each other. Biased. In this latched position, as shown in FIG. 4, the latch pins are radially inwardly directed toward the radially extending bore 79, locking the engaging portion 69 to the separating plunger portion 67. To achieve this latch condition, a relatively low pressure fluid flows from the oil passage 11c, which is the control pressure source, to the axially extending passage 75 and the force of the low pressure fluid acting on the radially inner surfaces of the pistons 91. The latch spring 89 is selected as a spring capable of overcoming this problem. Therefore, the latch spring 89 biases the latch pins 87 and the piston 91 to the latch position shown. In the latch condition, the lever support point defined by the latch housing portion 81 maintains its position as shown in Figs. 1, 2 and 4, whereby the pivot 39 of the rocker arm 33 rotates. But it does not move in the vertical direction. The rocker arm 33 operates in the usual way. That is, the engine poppet valve 17 moves between opening and closing positions in response to the periodic movement of the cam shaft 25, which is well known to those skilled in the art.

When the valve is to be operated in a non-operating mode, it is first necessary to increase the hydraulic pressure of the oil passage 11c, which is the control pressure source, to reach a relatively high pressure, wherein the relatively high pressure means that the pistons 91 of the latch spring 89 Sufficient to deflect in radial outward directions to the force. The pistons 91 are deflected outwardly enough to separate the latch pins 87 from the radially extending bore 79, thereby releasing the engaging portion 69 from the separating plunger portion 67. In other words, the engagement portion 69 is no longer secured with respect to the separating plunger portion 67 and can now move freely in the vertical downward direction opposite to the force of the lost motion spring 71 so as to move away from the snap ring 72. You lose. As will be appreciated by those skilled in the art, when the cam follower 37 engages with the base circle portion 29 of the cam shaft 25, the force acting on the engagement portion 69 is the force of the lost motion spring 71. However, the valve spring 19 is sufficiently stronger than the lost spring 71, so that when the lift portion 31 of the cam contour is engaged with the cam follower 37, the lost motion spring A downward force acting on the rocker arm 33 to overcome 71 and move the pivot 39 downward as shown in FIG. 3. In the valve non-operational conditions described now, the rocker arm 33 is newly rotated around the pad portion 35 which is the valve contact, but the engine poppet valve 17 is not moved at all due to the valve spring 19. Do not.

The invention has been described in great detail above, and it is believed that various modifications and variations to the invention will be apparent to those skilled in the art upon reading and understanding the specification. Therefore, it is intended that such variations and modifications be included in the present invention as long as they are within the scope of the appended claims.

Therefore, it has been described that the present invention provides a valve deactivator assembly that allows the use of the size of a conventional hydraulic lash regulator having the required length along the bore 45 of the cylinder head 11. Unlike the prior art, all the instruments required to achieve the valve deactivation are located outside the main part of the hydraulic lash regulator and are uniquely combined with the separating plunger portion 67 in areas where additional space is available.

Claims (7)

Valve means 17 for controlling the flow into and out of the combustion chamber 15, drive means having a time relationship to the state of the combustion chamber 15 and providing periodic movement to open and close the valve means 17. (25), a valve gear means that operates in response to the periodic movement to cause periodic opening and closing of the valve means 17, and a hydraulic lash regulator installed to fit the bore 45 of the cylinder head 11 ( 41, wherein the valve gear means has a rocker arm 33 having a valve contact portion 35 and a pivot portion 39 engaged with the valve means 17, the rocker arm 33 being the In response to the periodic movement of the drive means 25, it is usually rotated about the pivot 39, and the hydraulic lash adjuster 41 is rotated about the pivot 39 of the rocker arm 33. In the valve deactivator assembly 43 for an internal combustion engine: The hydraulic lash adjuster 41, A body member 49 disposed on the bore 45; A plunger portion 67 and an engaging portion 69 surrounding the plunger portion and engaging with the pivot portion 39 of the rocker arm 33, interlockable with the body member 49 and in the body member. A plunger assembly 53 reciprocally coupled to each other; It operates to lock the engaging portion 69 against the plunger portion 67 in the extended position when operating in the standard mode, and the engaging portion 69 against the plunger portion 67 when operating in the non-operating mode. A latch mechanism (79-91) operative to unlock; And And a biasing means (71) for biasing said engagement portion (69) towards said extended position. The method of claim 1, The drive means comprises a camshaft 25 defining a cam contour consisting of a base circle portion 29 and a lift portion 31, wherein the rocker arm 33 comprises a cam follower 37. The valve deactivator assembly 43. The method of claim 1, The pivot 39 of the rocker arm 33 includes a pair of sidewalls 40, the pair of sidewalls engaging the coupling 69 while the latch mechanism is in the standard, locking condition. And located adjacent to the top of the plunger portion 67, wherein the top of the plunger portion 67 is in the unlocked condition while the latch mechanism 79-91 is in the inoperative mode. Extending between 40, the drive means 25 exerting a force on the rocker arm in a direction opposite to the force of the biasing means 71 which biases the engagement portion 69 towards the extended position. Valve deactivator assembly (43). The method of claim 1, The cylinder head 11 includes a pressurized control fluid source 11c operative to interlock with the latch mechanism 79-91 and to bias the latch mechanism towards the unlocking condition, the latching mechanism being in the locking condition. A valve deactivator assembly (43), characterized in that it comprises a spring means (89) for biasing said latch mechanism toward. The method of claim 4, wherein The plunger assembly 53 includes a fluid passage 57p that is open to the pressurized control fluid source 11c and the plunger portion 67 is the latch mechanism 79-91 in the fluid passage 57p. Valve deactivator assembly (43), characterized in that it comprises a fluid passage (75) for providing open fluid delivery. The method of claim 5, When the engaging portion 69 is in the extended position, the engaging portion 69 and the plunger portion 67 are driven together to form aligned holes 79 and 83, the latch mechanism being opposed in diameter. A pair of latch pins 87 inwardly radially biased, the latch pins being in lock engagement with the plunger portion 67 when the pressurized control fluid source 11c contains a relatively low pressure fluid. Valve deactivator assembly (43). The method of claim 6, The plunger portion 67 includes a bore 79 facing in the radial direction and a pair of pistons 91 installed in the bore facing in the radial direction, the pistons being relatively to the pressurized control fluid source 11c. A valve deactivator assembly (43) characterized in that it acts in response to a fluid at high pressure to be biased outward of the radius to move the latch pins (87) radially out of the lock engagement with the plunger portion (67). ).