SE451487B - ARRANGEMENTS FOR A MULTI-CYCLE-INGOING ENGINE IGNITION SYSTEM - Google Patents

Abstract

An ignition head (16) is connected to each spark plug (3) of an internal combustion engine. Each ignition head (16) contains an ignition coil (15) and is electrically connected to a high-tension part common to a plurality of ignition heads (16). This comprises a control for triggering the generation of an ignition voltage in the ignition coils (15) connected to the high tension part. The ignition heads (16) and the high-tension part are separated from one another by a screening plate (17), which is a supporting structural element for the high-tension part and screens it from magnetic and electrical interference fields which originate from the ignition heads (16). This counters the risk of external interference influencing the control and leading to uncontrolled generation of ignition voltage. <IMAGE>

Description

451 487 15 ZÛ 25 30 35 In order to enable complete shielding on the outside of the interference fields emanating from the matches, in an advantageous embodiment of the invention the shield plate connects to the goods of the internal combustion engine and / or to parts attached to the internal combustion engine, preferably metallic parts. whereby the matches are enclosed in a chamber.

In a further embodiment of the invention, the shield plate consists of a lamella plate, where at least one lamella is electrically conductive and earthed directly or indirectly to the motor goods. This streamlines the shielding of, in particular, the electrical interference fields emanating from the matches. The other features of the invention are set forth in the appended claims and the following description of an exemplary embodiment of the invention. The description is made with reference to the accompanying figures, of which Figure 1 shows a partial view from above of an arrangement according to the invention with an Otto engine, and Figure 2 shows a section A-A according to Figure 1.

In the figures, a side part 1 shows a cylinder head 2 of a conventional Ottomotor, a number of spark plugs 3 being mounted in recesses 4 formed in the side of the cylinder head. To this is also attached with screws 5 an exhaust manifold 6, which connects to drainage channels (not shown) molded into the cylinder head 2.

The exemplary engine is four-cylinder and an exhaust manifold 6 connecting to the drain channel has four branches. The spark plug recesses 4 are also four in number and are distributed in pairs on either side of the two middle branches of the exhaust manifold 6. To each pair of spark plugs 3, which are mounted in each pair of recesses 4, a high voltage part 7,8 connects, which is part of an electronic ignition system for the engine. The two high-voltage parts 7,8 are connected to each other via an intermediate piece 9, which may also comprise electronic components common to the high-voltage parts. If the ignition system is of the capacitive type, as described in a Swedish patent with publication number 437 286 previously granted by the applicant '43 L * 15 20 25 30 35 451 487, the adapter can comprise a charging circuit with, among other things, a choke and a charging capacitor (not shown). Via a cable bundle 11, low-voltage direct current is obtained from a battery 12 to the charging circuit for up-transforming and charging the charging capacitor in a known manner. The cable bundle 11 also includes lines 14 from an electronics unit 13, which lines 14 lead control signals from the electronics unit 13 to trigger circuits (not shown) included in the high-voltage parts 7,8. Each spark plug 3 includes a trigger circuit, which upon receiving a control signal from the electronics unit 13 triggers the discharge of the charging capacitor through the primary winding of a spark coil 15 which cooperates with the spark plug 3 in question. Each ignition coil 15 is included in a match 16 which is directly connected to the spark plug 3 so that an ignition voltage generated in the secondary winding of the ignition coil 15 can be supplied to the same.

During ignition voltage generation, electric and magnetic fields can arise in the ignition coil 15, which can lead to the generation of undesired currents in nearby electrical circuits. In such cases, uncontrolled triggering can take place in the trigger circuit adjacent in the high-voltage section 7.8. To prevent this, as shown in Figure 2, a shield plate 17 is arranged according to the invention between the high-voltage part 7,8 and the matches 16. The shield plate 17 abuts against the upper edge of a support plate 18 attached to the cylinder head with screws 24. This forms an upwardly open pocket. which is closed by the screen plate 17.

For co-operation with the support plate 18, the end portion of the screen plate 17 is formed with a seam 19 which surrounds the support plate edge. Position fixing of the shield plate 17 takes place with screws 21 against the goods of the cylinder head 2 and possibly with a clamping device 22 between the housing 23 of the high-voltage part and the support plate 18.

The shield plate 17 constitutes a support element for a circuit board 25 included in the high-voltage parts 7,8, which, among other things, supports the electronic components included in the trigger circuits. The outer casing 23 is fixed with screws 26 to the shield plate 17 and encloses the circuit board 25, which is baked in epoxy plastic according to per se known "solid state technology".

From the circuit board 25, contact pins 27 emanate, which undergo electrically insulated heels 28 in the shield plate 17 for co-operation with connectors 29 connected to the ignition coil windings of the match piece 16. The match 16 and the high-voltage part 7,8, including the shield plate 17, are thus separable, which facilitates service and enables easier construction of the arrangement. In an alternative, not shown embodiment of the invention, where the spark plugs have different mounting angles in the recesses, terminal blocks on the support plate can be used as a connecting coupling between the match pieces and the high-voltage part.

The screen plate 17 is advantageously designed as a lamella plate with at least one lamella 30 made of an electrically conductive material, for example copper (Cu) or aluminum (Al). The lamella 30 is connected to the goods of the cylinder head 2 by means of the screws 21 and shields against the electric interference fields emanating from the match piece 16 during the ignition voltage generation. Furthermore, the shield plate 17 comprises at least one lamella 31 made of a ferromagnetic material, for example conventional transformer plate for shielding against the magnetic interference fields emanating from the match piece 16 during the ignition voltage generation. The slats 30,31,32 are insulated from each other with a thin insulating layer according to known transformer plate technology. For less stringent requirements for electrical shielding, all slats can be made of transformer plate.

The invention is not limited to the exemplary embodiment shown, but can be modified within the scope of the appended claims in a number of alternative embodiments.

Claims (7)

10 25 30 W 451 487 P A T E N T K R A V Arrangement of a ignition system of a multi-cylinder internal combustion engine, wherein to each ignition means (3) for the cylinders of the internal combustion engine connects an igniter (16) which each contains an ignition coil (15) for ignition voltage generation and is electrically connected to one for several matches common high voltage part (7, 8), which later comprises means for triggering ignition voltage generation in the ignition coils (15) connected to the high voltage part, characterized in that the ignition pieces (16) and the high voltage part (7, 8) are separated of a shield plate (17) which forms a support element for the high-voltage part (7,8) and which shields it from magnetic and electric interference fields emanating from the matches (16). ^ Arrangement according to claim 1, characterized in that the shield plate (17) connects to the goods (2) of the internal combustion engine and / or attached, preferably metallic parts (18) to the internal combustion engine, whereby the matches (16) are enclosed in a chamber. Arrangement according to claim 2, characterized in that the shield plate (17) is releasably attached to the goods (2) of the internal combustion engine or metallic parts (18) attached thereto. Arrangement according to claim 1, characterized in that the shield plate (17) consists of a lamella plate with at least one lamella (30), which is electrically conductive and earthed directly or indirectly to the motor goods (2). Arrangement according to claim 4, characterized in that at least one lamella (30) is made of a ferromagnetic material. Arrangement according to one of the preceding claims, characterized in that the high-voltage part (7, 8) is shielded relative to the surroundings by a metallic housing (23) and possibly adjacent motor parts. 451 487 Arrangement according to one of the preceding claims, characterized in that at least one insulated primary inlet connection (27, 29) passes through the shield plate (17). m;