FR2783033A1 - ARRANGEMENT FOR THE ELECTROMAGNETIC CONTROL OF A VALVE - Google Patents

Abstract

The invention provides an arrangement (10) for controlling a valve (14), the stem (18) of which extends through a housing (23) formed in the cylinder head (24) and which receives a spring (30). valve return, and of the type comprising an electromagnetic actuator (12) which comprises an actuating rod (62) which projects vertically inside the housing, so that its lower free end face (90) cooperates with the upper free end face (48) of the stem (18) of the valve (14), under the action of an actuator spring (74), characterized in that the two actuating springs ( 74) and return (30) of the valve (14) are arranged vertically one above the other inside the housing (23).

Description

"Arrangement for the electromagnetic control of a valve" The present

  The invention relates to an arrangement for the electromagnetic control of a valve of a combustion engine, in particular of a motor vehicle. The invention relates more particularly to an arrangement of the type described and represented in document WO-A-96/19643 in which the stem-shaped tail of the valve is guided in sliding in a corresponding portion of the cylinder head of the engine. and whose free upper end section extends through a housing formed in the cylinder head which opens into an upper face portion of the cylinder head and which receives a return spring from the valve concentric with the valve stem and i which is interposed between the lower bottom of the housing and an upper bearing cup carried by the valve stem near its upper free end, and of the type comprising an electromagnetic actuator whose body is fixed to the cylinder head and which comprises a rod actuator which projects vertically below a bottom face of the actuator to extend vertically inside the housing, substantially coaxial with the valve stem, so that its lower free end face cooperates with the upper free end face of the stem

  valve, under the action of an actuator spring.

  In order to reduce the overall height of the actuator which extends above the cylinder head, FIG. 2 of this document represents an arrangement in which the actuator spring, concentric with the lower end section of the actuating rod , is arranged inside the housing and is interposed between a portion facing the underside of the actuator body and a lower bearing cup supported

  by the lower end section of the actuating rod.

  In the arrangement proposed in FIG. 2, the two return springs for the valve and for the actuator are two concentric springs mounted one inside the other, that is to say that the return spring for the valve , of smaller outside diameter, is arranged axially inside the actuator spring. This design has several drawbacks. First of all, the shape of the actuator spring support cup is particularly complex and the fact that it extends axially between the valve return spring and the actuator spring further increases the mean diameter of the

actuator spring.

  In addition, fixing the disc-shaped body of the actuator spring bearing cup to the free end

  lower of the actuating rod is not very easy.

  Finally, the concentric arrangement of the two springs results in a total radial bulk, that is to say a

  average outside diameter of the actuator spring, particular-

  important. Such a large radial size does not make it possible to reduce, in a desirable manner, the angle or V formed by two adjacent valves of the same cylinder of the combustion engine each controlled by means of such a

layout.

  In order to remedy these drawbacks, the invention proposes an arrangement of the type mentioned above, characterized in that the two actuator and return springs of the valve are arranged vertically one at the

  above each other inside the housing.

  According to other features of the invention - the mean outside diameters of the two springs are substantially equal; - Each spring is a compression coil spring; each bearing cup comprises, in one of its transverse faces, a seat for centering the associated end of the corresponding spring and comprises another opposite transverse face substantially adjacent to the corresponding end of the actuating rod, of the valve tail respectively; - The housing is a cylindrical housing whose upper end is sealed in a sealed manner by a complementary portion of the underside of the body of the actuator. 1 5 Other characteristics and advantages of the invention

  will appear on reading the detailed description which follows

  for the understanding of which reference will be made to the appended drawings in which: FIG. 1 is a view in axial section of an arrangement produced in accordance with the teachings of the invention for controlling a valve; and - Figure 2 is a schematic view illustrating the application of the teachings of the invention to two adjacent V-shaped valves, exhaust and intake of a

  motor vehicle combustion engine.

  The arrangement 10 illustrated in FIG. 1 comprises an electromagnetic actuator 12 for controlling a valve 14 of which only the upper end section 16 of

  its stem-shaped tail 18 is illustrated in FIG. 1.

  The upper end section 16 is guided in sliding along a vertical axis XX by a tubular valve guide 20 which is mounted through a bore 22 formed in the body 24 of the cylinder head so that the upper free end section s extends axially upwards inside a coaxial cylindrical housing 23 formed in the body 24 and which is delimited by an annular lower bottom 26 s and which opens at its upper free end in a

  portion 28 of the upper face of the body 24 of the cylinder head.

  In a known manner, the valve 14 is returned to the closed position by a valve return spring 30 which is a helical, or coil, compression spring of substantially cylindrical shape, slightly frustoconical, whose lower coil 32 is supported against the lower bottom 26 of the housing 23 and whose upper turn 34 bears against the lower transverse face opposite 36 of a cup

  38 for the valve spring 30.

  The transverse underside 36 of the cup 38 has a seat 40 for centering the upper turn 34. In a known manner, the cup 38 is retained

  axially upwards on the valve stem 16 via the

  median of a ring 44, so that the planar upper transverse face 46 of the support cup 38 extends near the upper end transverse face 48 of

the valve stem 16.

  As can be seen in Figure 1, the valve spring 30 is arranged at the bottom of the housing 23, the inside diameter of the latter being slightly greater

  the mean outside diameter of the valve spring 30.

  The electromagnetic actuator 12 comprises a body of generally cylindrical or prismatic shape which is coaxial with the axis X-X of the valve 14 and which is fixed on the

cylinder head 24 by screws 52.

  In known manner, the body 50 contains two electro-

  upper 54 and lower 56 magnets which are capable of acting on an actuating plate in the form of a parallelepiped or a disc 58 which is mounted crimped at the upper end 60 of a rod 62 for actuating the

valve 14.

  The central section 64 of the actuating rod 62 is guided in vertical axial sliding in a sleeve 66 which is here produced integrally with the lower plate 68 of the body 50 of the actuator 12, the latter being supported by

  its annular underside 70 on the upper portion facing

  opposite 28 of the upper face of the cylinder head 24.

  The lower face 70 also includes a lower cylindrical extension 72 which is received axially in the upper part s5 of the cylindrical housing 23 to close the latter

tightly.

  According to a known design, the actuator 12 also comprises an actuator spring 74 which is a helical spring, or a coil spring, of compression slightly conical in shape and which is interposed axially between a portion opposite the face lower 75 of the extension 72 against which it bears by its upper turn 76 and a support cup 78 which is delimited by an upper transverse face 80 comprising a seat 82 for centering the lower turn

84 of actuator spring 74.

  The support cup 78 of the actuator spring 74 is retained axially on the actuation rod 62 by a ring 86 so that the lower transverse face 88 of the support cup 78 is located near the face

  lower end 90 of the actuating rod 62.

  In accordance with the teachings of the invention, and as can be seen in FIG. 1, the actuator spring 74 is arranged inside the cylindrical housing 23 in the upper part of the latter, and it is located vertically above the

valve spring 30.

  This arrangement makes it possible to adopt for the actuator spring 74 and for the valve spring 30 substantially the same radial dimensions, that is to say that the mean outside diameter of the actuator spring 74 is substantially equal to the outside diameter. valve spring 30 so as to minimize the inside diameter of the

io cylindrical housing 23.

  Thanks to the arrangement according to the invention in which the internal diameter of the cylindrical housing 23 is reduced, it is possible, as can be seen in FIG. 2, to reduce the angle A between the axes of two adjacent valves such as for example an exhaust valve 14 visible on the left in FIG. 2 and an intake valve 14 'shown on the right, each of the two valves being controlled by an electromagnetic actuator in accordance with the teachings of the invention. The reduced diameter of the housings 23 and 23 'allows the reduction of the angle A while retaining sufficient space, for example for the passage of a fuel injector and / or a spark plug received in a housing 100 of the

cylinder head 24.

Claims (5)

  1. Arrangement (10) for controlling a valve (14) of a combustion engine, in particular of a motor vehicle, the stem (18) of which is in the form of a rod and is slidably guided in a corresponding portion of the cylinder head (24) of the engine and whose free upper end section (16) extends through a housing (23) formed in the cylinder head (24) which opens into a portion (28) of the upper face of the cylinder head (24) and which receives a spring (30) for returning the valve concentric with the valve stem (16) and which is interposed between the lower bottom (26) of the housing (23) and an upper bearing cup (38) carried by the stem (18) of the valve (14) near its upper free end (48), and of the type comprising an electromagnetic actuator (12) whose body (50) is fixed on the cylinder head (24) and which comprises a rod actuation (62) which projects vertically below a lower face (70) for supporting the actuator (12, 5 0) on the cylinder head (28, 24), to extend vertically inside the housing (23), substantially coaxial with the stem (18) of the valve (14), so that its end face is free lower (90) cooperates with the upper free end face (48) of the valve stem (18) (14), under the action of an actuator spring (74) concentric with the lower end section of the actuating rod (62), arranged inside the housing (23) and which is interposed between a portion (72) facing the underside (70) of the body (50) of the actuator (12) and a lower bearing cup (78) carried by the lower end section of the actuating rod (62), characterized in that the two actuating (74) and return (30) springs ) of the valve (14) are arranged vertically   one above the other inside the housing (23).   2. Arrangement according to claim 1, characterized in that the mean outside diameters of the two springs (74, 30) are substantially equal.   3. Arrangement according to one of claims I or 2,   characterized in that each spring is a spring of coil compression (74, 30).   4 Arrangement according to any one of   io the preceding claims, characterized in that each   support cup (78, 38) comprises, in one of its transverse faces (80, 36), a seat (82, 40) for centering the associated end (84, 34) of the corresponding spring (74, 30) and has another substantially transverse opposite face (88, 46) i5 adjacent to the corresponding end (90, 48) of the actuating rod (62), of the tail (18) of valve (14) respectively.   5. Arrangement according to any one of   previous claims, characterized in that said   housing (23) is a cylindrical housing, the upper end of which is sealed off by a complementary portion (72) of the underside of the body (50) of the actuator (12).