FR2781255A3 - Ignition arrangement for multi-cylinder internal combustion engine overcomes adverse effect by coils becoming taught as result of temp. fluctuations, fitting tolerances - Google Patents

Abstract

The ignition arrangement has several, pref. identical, ignition coils (12) held in a carrying unit (21) for simultaneous mounting in fitting points primarily in a row on the engine. Each coil is held in the carrying unit by a locating arrangement (26) that enables relative movement between the coil and carrying unit.

Description

STATE OF THE ART The present invention relates to a device

  for an internal combustion engine with more than one

  cylinders with multiple ignition coils

  identical rence, which are carried by a support unit for simultaneous mounting preferably on locations

  for in-line mounting of an internal combustion engine.

  We already know such an ignition device

  lon EP 0 512 357 A2 in that several separate ignition coils are mounted separately on a support unit and their high voltage domes come out of this

support unit.

  A complete support unit can then be mounted by a one-piece mounting link on the

  cylinder head of an internal combustion engine and thus connect if-

  simultaneously all the ignition coils to the corresponding spark plugs

  of the internal combustion engine.

  However, the drawback of this solution is that the ignition coils are rigidly fixed in the support unit, so that after having made the connection with the spark plugs, installed in a fixed and rigid manner, the temperature variations or mounting tolerances can create stresses endangering the

  operating safety of the ignition device.

  Advantages of the invention The object of the present invention is to remedy these drawbacks and to this end relates to an ignition device of the type defined above, characterized in that the fixing of each of the ignition coils in the unit support is achieved by a bearing device allowing relative movement between the ignition coil and the support unit.

  The ignition device according to the invention, pre-

  feels the advantage over the state of the art,

  avoid the above irregularities. So each of the bo-

  ignition ignition is mounted in the support unit by a bearing device allowing relative mobility between the ignition coil and the support unit. This flexibility

  allows the necessary flexibility of the connection between the bo-

  ignition and support unit, even under the effect of temperature variations and installation conditions

  linked to manufacturing tolerances, which

  guarantees the operational safety of the device

  ignition even under such conditions of use

  plicated. According to other advantageous features of the invention: the bearing device comprises at least one element

  hooking on the ignition coil and a re-element

  corresponding ception in the support unit and the

  range of the attachment element on the receiving element is effected by the engagement of the ignition coil in the support unit, - the relative movement between the ignition coil and the support unit is limited by an element of limitation,

  - the ignition coils are bar-shaped coils.

Drawings

  An exemplary embodiment of the invention is shown

  presented in the drawings and will be described below in more detail. Thus: - Figure 1 is a perspective view of the ignition device in the form of separate construction units, - Figure 2 shows a bearing device for a coil

of a support unit.

  Description of the exemplary embodiment

  According to Figure 1, an ignition device 11

  an internal combustion engine with several cylinders,

  carries several ignition coils 12 depending on the number of cycles

  engine liners. The ignition device 11 is provided in a known manner and not shown in detail, to be mounted on the cylinder head of an internal combustion engine. The cylinder head comprises for each cylinder and starting from an inlet orifice, spark plug wells with circular section. Each candle well fixedly receives a spark plug 13 so that these locations of the candles 13 which are preferably in line, constitute a rigid and fixed arrangement of the candles. Each of the spark plugs 13 comprises on the side of the inlet orifice, a high voltage terminal for coming in.

  contact with an ignition coil 12.

  The ignition coils 12 are made of pre-

  ference in the form of ignition coil bars with a housing 16 having a cylindrical base shape. The diameter of the housing 16 is less than the clearance of the diameter of the well of

  spark plug so that the ignition coils 12 are not blocked

  rigidly placed in the spark plug wells, but have a

  some mobility within the framework authorized by the game.

  In the axial alignment, on one side of the housing 16 of the ignition coils 12, there is a first end segment 17 to come against the high voltage terminal of

  the associated candle 13 and on the other side, opposite, we have a

cond end segment 18.

  The second end segment 18 is provided with contact elements 19 directed axially and having the form of flat tongues serving for contacting with

  corresponding contact elements not shown of a uni-

  support tee 21; the corresponding contact elements

  are grouped on a connector 22 constituting the branch-

  of the primer at one end of the support unit 21.

  The support unit 21 rectangle, which consists of a base body 23 and a cover 24 which can engage and hang on the base body, not only ensures contacting on the low voltage side ignition coils 12, but also as a support element. For this purpose, for each ignition coil 12, there is provided a device for

  bearing or reception 26.30 The bearing device 26 according to FIG. 2 includes

  door on the side facing the second end segment 18 of

  the ignition coil 12, a suspension element 27 consisting

  killed by a mushroom-shaped hook made of plastic

  than. Correspondingly to the suspension element 27, the bearing device 26 comprises in the base body 23, a suspension element 28 in the form of two latching rails 29 parallel, each with a hook 31

  jagged, distributed in line.

  The snap rails 29 are pushed back when

  that the ignition coil 12 is axially engaged in the base body 23 of the support unit 21 by the penetration of the suspension element 27 into the hooking zone of the hooks 31 while the suspension element 27 slides along the pair of hooks which is engaged and which has been radially widened, until the suspension element hooks behind the reception element 28 and blocks the antagonistic movement of the reception element 28. This operation is repeated l0 until the ignition coil 12 is at the full driving depth in the body.

basic 23.

  By engaging the cover 24 on the base body 23, the cover being shown remote from the base body to

  Figure 1, the limiting elements 32 in the form of bar-

  cover racks 24 pass on the snap rails

  29 so that they can no longer deviate radially.

  This limits the radial elastic travel of the latching rails 29 so that the ignition coil 12 is on the one hand linked by a form link in the support unit 21 and that the ignition coil 12 on the other hand free part in the support unit 21 to have an angular mobility of

  the order of +/- 5 in the direction of the longitudinal extension

support unit 21.

  By this fixing of the ignition coils 12 on the support unit 21, there is on the one hand the rigidity of this connection which allows the mounting or dismounting of the connection on the cylinder head of the internal combustion engine during a

single assembly step.

  In addition, the different ignition coils 12 have, thanks to the angular mobility, a degree of freedom and the possibility of adapting their position optimally with respect to the support unit 21 as a function of the expansions generated by the temperature, the operation of the internal combustion engine or according to the different conditions of

  assembly linked to manufacturing tolerances.

  This prevents any blockage of the coils

  12 installed in a single assembly on the tank

  tired of the internal combustion engine and guaranteed safety

  rite of operation of the ignition device 11 in the

  difficult operating conditions.

RE V E N D I C A T I ON S

  1) Ignition device for an internal combustion engine with several cylinders comprising several ignition coils (12) preferably identical, which are carried by a support unit (21) for simultaneous mounting preferably on mounting locations in line of an internal combustion engine, characterized in that the fixing of each of the ignition coils (12) in the support unit (21) is done by a bearing device (26) allowing a relative movement between the coil

  ignition (12) and the support unit (21).

  2) Ignition device according to claim 1, characterized in that the bearing device (26) comprises at least one hooking element (27) on the ignition coil (12) and a receiving element (28) corresponding in the support unit (21) and the coupling of the hooking element (27) on the receiving element (28) is effected by the engagement of the coil

  ignition (12) in the support unit (21).

  3) An ignition device according to claim 2, characterized in that the relative movement between the ignition coil (12) and

  the support unit (21) is limited by a limiting element

tion (32).

  4) Ignition device according to one of claims

1 to 3,

characterized in that

  the ignition coils (12) are bar-shaped coils

res.