GB2185859A

GB2185859A - Electronic module for ignition distributor units of motor vehicles

Info

Publication number: GB2185859A
Application number: GB08701267A
Authority: GB
Inventors: Gilberto Izzi
Original assignee: Magneti Marelli SpA
Current assignee: Marelli Europe SpA
Priority date: 1986-01-29
Filing date: 1987-01-21
Publication date: 1987-07-29
Also published as: IT207051Z2; ES1005100Y; DE8701211U1; ES1005100U; IT8652909V0; FR2593558A3; GB8701267D0; FR2593558B3

Abstract

An ignition distributor unit for internal combustion engines comprises a closed metal support housing (1) for an ignition pulse generator and an ignition distributor, and an electronic control circuit module (5) fixed to the outside of the housing (1). The module (5) is fixed to the housing (1) by an intermediate metal support member (10) acting as a heat radiator located in heat- exchange relationship with the circuits of the module (5) and the housing (1), and shaped so as to define, together with the outer surface of the housing (1), ventilation passages for minimising heat exchange between the intermediate support (10) and the housing (1). <IMAGE>

Description

SPECIFICATION Ignition distributor unit for internal combustion engines, particularly for motor vehicles The present invention relates to an ignition distributor unit for internal combustion engines, particularly for motor vehicles.

More specifically, the invention concerns an ignition distributor unit of the type comprising a metal support housing in which there is mounted an ignition pulse generator and at one end of which, in a cap, there is an ignition distributor, the unit further including an electronic module fixed to the outside of the housing and including control circuit means connected to the pulse generator and intended for connection to the ignition coil to control its conduction of current.

The object of the present invention is to provide an ignition distributor unit for internal combustion engines in which excessive heating of the circuits of the electronic module is effectively avoided.

This object is achieved according to the invention by means of an ignition distributor unit of the type mentioned above, the main characteristic of which lies in that the electronic module is fixed to the housing by an intermediate metal support member acting as a heatradiator located in heat-exchange relationship with the circuit means of the module and shaped so as to define, together with the outer surface of the housing, ventilation passages for minimising heat exchange between the intermediate support and the housing.

According to a further characteristic, the intermediate support member is preferably shaped as a bridge and is fixed releasably to the housing in correspondence with its lateral supports.

It may conveniently be provided with integral cooling fins.

Further characteristics and advantages of the ignition distributor unit of the invention will become apparent from the detailed description which follows with reference to the appended drawings, provided purely by way of non-limiting example, in which: Figure 1 is a perspective view of an ignition distributor unit according to the invention, Figure 2 is an exploded perspective view of the unit shown in Fig. 1, Figure 3 is a section taken on the line Ill-Ill of Fig. 1, and Figures 4 and 5 show in perspective two intermediate support members usable in the distributor unit of the invention.

With reference to Fig. 1, an ignition distributor unit of the invention includes a metal sup port housing 1 in which an electromagnetic ignition pulse generator of known type is mounted. This pulse generator may include, for example, a toothed hub or timer rotated by the distributor shaft and cooperating with a small pick-up coil of conductive wire.

To the housing 1 is fixed a vacuum advance corrector 2.

To one end of the housing 1 is fixed a cap 3 within which the ignition distributor proper is mounted in known manner.

In an aperture 1 a of the housing 1, as seen particularly in Fig. 2, is an electrical connector 4, for example of the blade-contact type, connected to the pulse generator housed within the housing.

An electronic module, generally indicated 5 in Figs. 1 to 3, enclosed circuits for controlling the conduction of current by the ignition coil. As shown particularly in Fig. 2, the module 5 has a first connector 5a which is coupled to the connector 4 carried by the housing 1 and a second connector 5b for connection to the ignition coil (not illustrated).

As shown schematically in Fig. 3, control circuits 6 are housed in the electronic module 5 and are formed, for example, in accordance with the technology of thick-film hybrid circuits. The electronic module 5 has beneath it a conductive plate located so as to be thermally coupled to the circuit 6.

The electronic module 5 is fixed to the module 1 with the interposition of an intermediate support member, indicated 10. This support member 10 is made from a material which is a good conductor of heat, for example, copper or its alloys, aluminium or its alloys, preferably alloys of aluminium and manganese.

As shown particularly in Figs. 2 and 4, the support member 10 is shaped as a bridge and has its shaped ends acting as supports. These ends have respective notches 10a and 10b for the passage of screws 11 for releasabiy fixing this intermediate member to the housing 1 of the distributor. These screws engage correspondingly threaded holes 12 in the housing 1.

The electronic module 5 is fixed to the flat upper surface of the intermediate support member 10 by screws 13. In the assembled condition, as shown in Fig. 3, the conductive plate 7 is in heat-exchange relationship between the control circuits 6 of the electronic module and the intermediate support member 10 and hence with the housing or body 1 of the distributor.

Due to its bridge shape, the support member 10 defines a ventilation passage with the outer surface of the body 1 of the distributor; the ventilation is forced when the vehicle is moving, and is conventive when the vehicle is stationery.

Conveniently, as shown in Fig. 5, the inter mediate support member may be provided with integral cooling fins.

In operation, by virtue of the type of as sembly illustrated, the unit of the invention enables excessive heating of the circuits of the electronic module 5 to be avoided or reduced by the dissipation of heat through the body of the distributor 1 by means of the intermediate support member 10 and the ventilation which is very effective by virtue of the particular shape of the intermediate support member.

Claims

1. Ignition distributor system for internal combustion engines, comprising a closed metal support housing in which there is mounted an ignition pulse generator and at one end of which, in a cap, there is an ignition distributor, the unit further including an electronic module fixed to the outside of the housing and including control circuit means connected to the pulse generator and intended for connection to the ignition coil to control its condition of current, in which the electronic module is fixed to the housing by an intermediate metal support member acting as a heat radiator located in heat-exchange relationship with the circuit means of the module and with the housing, and shaped so as to define, together with the outer surface of the housing, ventilation passages for minimising heat exchange between the intermediate support and the housing.

2. Unit according to Claim 1, in which the intermediate support member is shaped essentially as a bridge and is fixed releasably to the housing in correspondence with its lateral supports.

3. Unit according to Claim 2, in which the intermediate support member is fixed to the housing by screws.

4. Unit according to any one of the preceding claims, in which in that the intermediate support member is made from a material chosen from the group including copper and its alloys, and aluminium and its alloys.

5. Unit according to Claim 4, in which the intermediate support member is made from an alloy of aluminium and manganese.

6. Unit according to any one of the preceding claims, in which the electronic module is fixed releasably to the intermediate support member by screws.

7. Unit according to any one of the preceding claims, in which the intermediate support member is provided with integral cooling fins.

8. Ignition distributor unit for internal combustion.engines, substantially as herein described with reference to, and as shown in, the appended drawings.