per WORLD INTELLECTUAL PROPERTY ORGANIZATION International Bureau

INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT

(51) International Patent Classification 4 ; (11) International Publication Number: WO 89/1 H01G 4/32, 4/40, HOIS 31/009 Al

(43) International Publication Date: 2 November 1989 (02.

(21) International Application Number : PCT/IT89/00024 (81) Designated States: AT (European patent), AU, B (European patent), BF (OAPI patent), BG, BJ (

(22) International Filing Date : 12 April 1989 (12.04.89) patent), BR, CF (OAPI patent), CG (OAPI patent) (European patent), CM (OAPI patent), DE (Eur patent), DK, FI, FR (European patent), GA (OA

(30) Priority data: tent), GB (European patent), HU, IT (European pa

83365 A/88 18 April 1988 (18.04.88) IT JP, KP, KR, LK, LU (European patent), MC, MG (OAPI patent), MR (OAPI patent), MW, NL (Euro patent), NO, RO, SD, SE (European patent), SN (

(71) Applicant (for all designated States except US): DUCATI patent), SU, TD (OAPI patent), TG (OAPI patent),

ENERGIA S.P.A. [IT/IT]; Via Marco Emilio Lepido, 182, 1-40132 Bologna (IT).

Published

(72) Inventors; and With international search report.

(75) Inventors/Applicants (for US only) : BIONDI, Astorre [IT/ Before the expiration of the time limit for amendin IT]; TURA, Dante [IT/IT]; Via Marco Emilio Lepido, claims and to be republished in the event of the rece 182, 1-40132 Bologna (IT). amendments.

(74) Agent: D'AGOSTINI, Giovanni; D'Agostini Organizzaz- ione, Via G. Giusti, 17, 1-33100 Udine (IT).

(54) Title: IMPROVED CAPACITOR WITH CONTROLLED IMPEDANCE

(57) Abstract

A capacitor with controlled impedance, con¬ sisting in a reel obtained from the winding of foils/ strip implicating in overlap alternated at least: a me¬ tallic conductor sheet/foil/strip (a) ; a first dielectric insulating foil/film/strip (b), metallized (b') from the side opposed to the adjacent metallic conductor sheet/foil/strip (a); a second dielectric insulating foil/film/strip (c).

FOR THE PURPOSES OF INFORMAπON ONLY

Codes used to identify State- i party to the PCT on the front pages ofpamphlets publishing international appli- cations under the PCT.

AT Austria FR France ML Mali

AU Australia GA Gabon MR Mauritania

BB Barbados GB United Kingdom M Malawi

BE Belgium HU Hungary NL Netherlands

BG Bulgaria IT Italy NO Norway

BJ Benin P Japan RO Romania

BR Brazil KP Democratic People's Republic SD Sudan

CF Central African Republic ofKorea SE Sweden

CG Congo KR Republic of orea SN Senegal

CH Switzerland LI Liechtenstein SU Soviet Union

CM Cameroon LK Sri Lanka TD Chad

DE Germany, Federal Republic of LU Luxembourg TG Togo

DK Denmark MC Monaco US United States of America

Improved capacitor with controlled impedance

The object of this invention is a capacitor with controlled impedance. The invention founds particular even if not exclusive application into systems of ignition for i.e. motors.

In prior art the characteristics of this capacitors are disclosed in the IT- 83490A/87 and IT-83491 A/87 in the name of same applicant. These solutions foresee a new integrated sets of capacitors in which capacity and inductive effect is integrated in a single device (foil/strip reel). This capacitor is conveniently used in spark generation for i.e. motors as suggested from the Italian patent application IT-83490A/87, by means of coaxial insertion inside the high voltage circuit, said integrated inductive-capacitor.

In this solution is disclosed the winding of metallic conductor strip with an insulating dielectric strip foreseen even the possibility to use stratified metallized plastic strip (stratification).

An object of the present invention is to to embody an improved inductive-capacitor with metallized plastic strips.

This and others aims will reached with the present innovation as claimed solving the problems exposed by capacitor with controlled impedance, consisting in a reels obtained from the winding of a package of leaves implicating in overlap alternated at least: - a metallic conductor sheet/foil/strip; - a first dielectric insulating foil/film/strip, metallized from the side opposed to the adjacent metallic conductor strip;

- a second dielectric insulating foil/film/strip. One border of metallization of said first dielectric insulating strip being conductively placed in short-circuit by metallization of the head of the respective reel remaining insulated said metallic conductor sheet/foil/film/strip. In order to allow the electric linkage the following elements are provided: - a first electric conductor with capacitive effect, linked to said metallization in head; - at least a second electric conductor from an internal extremity of the said metallic conductor sheet/foil/strip; - at least a third electric conductor from the exterior opposed extremity of said metallic conductive sheet/foil/strip. With this solution is obtained an inductive-capacitor able to operate in integrated inductive-capacitive function particularly useful in i.e. sparking devices. Being allowed to reduce the respective encumbrance and costs of the entire device, by automatic coaxial insertion of the inductive-capacitor inside the spark high tension winding.

These and others advantages will appear from the next itemized description of preferentials solutions with the enclosed drawings the particulars of execution have not to be considered limitative but by way of example only. Figure 1 represents a schematic outlook view in axial section of the device of this invention. Figure 2 represents a partial magnified view of the winded set of layers and of the respective linkage to the reel head metallization . Figure 3 represents a schematic view of an example of electric schema of the device for i.e. motors ignition.

With reference to figure 1 it can be pointed out that the winding having function of inductor and capacitor as for the invention is composed of three strips alternately disposed respectively: - a metallic conductor sheet/foil/strip (eg. aluminium, a); - a first dielectric foil/fiim/strip (Eg. plastic material film of polypropylene b), metallized on the opposed surface (b'); - a second dielectric insulating foil/film/strip (Eg. film of polypropylene (c)).

As for this invention the metallic sheet strip (a) is shorter than metallized dielectric foil/film/strip (b'). In order after winding in reels to allow reel head metallization (d) to short-circuit the respective edges of dielectric metallized foil/strip (b'). The electric terminals will be the following: 1 ) head conductor metallization (d); 2) electric linkage to the internal extremity of the winded metallic conductor sheet/foil/strip (a) ; 2') electric linkage to the external extremity of said winded metallic conductor sheet/foil/strip (a), being destined the last two to explicate the inductive function.

Making reference to Fig.3 it can be pointed out that setting the device as represented in Fig.1 (A) is coaxially inserted into a spark high tension induced winding (3-B), in order to deliver spark in a plugs of ignition (4). In this way the device can function in simple and very reliable mode foreseen to link the terminals (1 , 2, 2') of the device of which to the present invention with: - a generator (G) with respective internal resistance (R), - across two breaker means connected in serial (Eg. diodes, SCR, etc. I, I') operatively linked in order that when one (the first) closes the second open or viceversa (P) ;

- with the contrivance that the terminal (1 ) of the metallized head is linked between the respective opposed switches (I, I'), and the respective terminals (2, 2') of the metallic conductor sheet/foil/strip (a) linked from one side to said second switch into respective linkage in serial (I') and from the other to said generator (G) .

Naturally into the ambit of this exemplificative circuit numerous variations can be made.