WOUND CAPACITOR DEVICE WITH CONTROLLED IMPEDANCE

Abstract: Wound capacitor device with controlled impedance, in the form of a coil, comprising at least two metallic conductive sheets or layers (B, B') wound in a roll, and insulated by sheets or layers in dielectric insulating material (A), of which: at least one of said metallic conductive sheets or layers (B) is connected on one side with an electric conductor (1); at least one of said metallic conductor sheets or layers which is insulated from the previous one/s (B') is connected with electric conductor/s on the opposite side (3), so as to realize after winding in coil a respective capacitor (4) from the first sheet (B); a respective inductor (5) from the second sheet (B'); all of it being integrated in a sole coil.

Description: WOUND CAPACITOR DEVICE WITH CONTROLLED IMPEDANCE The subject of the present invention is a wound capacitor device with controlled impedance. This invention has a particular and convenient, although not exclusive, application in all sectors where the maximum miniaturization of inductors is desired and where its use is necessary in series of capacitor means. A main apparatus realizable with this device is an ignition system with capacitor integrated in the inductor. It results necessary in the present state of art to utilize two separate devices, respectively, an inductor and a capacitor or viceversa to be connected in series. The above involves the impossibility of being able to noticeably reduce both the overall dimensions and the costs above the limit deriving from manufacturing each device separately. The main scope of the present invention is to eliminate the above- mentioned inconveniences. Further, in ignition systems, in addition to an inductor in a respective induction coil, it results necessary to use a capacitor to accumulate the necessary discharge energy, elements which are well- known to be constituted of two devices which are distinctly separate. A further scope of this invention is to provide for the integration of these two devices in a sole device, having the inductance and capacitance inserted directly in the inductor coil and, therefore, without the necessity of a separate capacitor in the respective ignition circuit. The solution to the problem is produced by the following considerations: - it is known that a capacitor always has combined leaks from the inductor and the resistance, suns 1 rUTϋ SHEET - the inductor is in function of the geometry and length of the armatures - the resistance is in function of the materials: thickness, surfaces, dielectric, - the capacity is in function of the dielectric and of the armature surfaces, - the immediate consequence is that it has always been necessary to try and eliminate, or reduce as much as possible, the respective leaks (e.g. by introducing the system having metallized or short-circuited winding heads by the armature projection; by use of multiple output terminals on said armature, central outputs, etc.). Surprisingly enough, it has been found that this tendency to improve the capacitors' efficiency obstructed the way for an invention to solve the above-mentioned problems. The way taken to arrive at the present result has been the exact opposite, that is to say, working on the structuration of one of these elements, in this specific case, the capacitor, so as to vary its form and give it the possibility to also supply other performances by working on the geometry and on its structure so as to magnify the leaks up to the point of getting them under control. The present invention, according to the characteristics given in the attached claims, intends reaching the cited purposes and others, and solve the problems explained by means of a wound impedance-capacitor device, in the form of a coil, characterized by the fact of comprising at least two metallic conductor sheets or layers wound in a roll and electrically insulated, of which: - at least one of said metallic conductor sheets or layers presents a connection on one side with an electric conductor; - at least one of said metallic conductor sheets or layers insulated from the previous one/s, presents at least one connection with electric conductor/s on the opposite side so as to realize after winding in coil of: SUBSTITUT!.? ^HΞET - a respective capacitor from the first sheet/layer, - a respective inductor from the second sheet/layer; all of it being integrated in a sole coil. The said second sheet advantageously presents at least two opposed electric conductors. The dielectric insulating separator layers are also advantageously in 5-10 micron polypropylene sheet, while the conductor layers are in aluminium. In practice, two or more metallic armatures are used which are not directly short-circuited, and which are separated by any type of dielectric. In the preferential solution the dielectric insulating separator layers, the conductor ones wound in coil, are integrated by impregnation in epoxide resin. The advantages obtained from these characteristics consist essentially in the fact that, in addition to combining the twin function of capacitor and inductor in a sole device and reducing both the total overall dimensions and the respective manufacturing costs, the respective impedance can be controlled. In the realization of an ignition device, the whole ignition circuit is reduced in dimension, simplified in the number of component parts and realized at a considerably lower cost. These and other advantages will appear in the following, detailed description of preferential realization solutions with the help of the attached drawings, the execution details of which are not to be' held as limiting but only as examples. Figure 1 gives a schematic, front prospect of the sheets making up the device as per the invention in unwound condition. SUBSTSTUTΞ SHΞET Figure 2 gives a prospect of the finished device wound up in coil and ready for use. Figure 3 gives a view of the equivalent electric scheme obtainable . - during operation of the device. Figure 4 gives the electric scheme of an example of application which can be adopted in an ignition system for endothermic motors. Figure 5 gives a schematic, cross-section of the coil which transforms the current from low voltage to high voltage, realized with the inductor device as per the present invention. With reference to the figures, it can be seen that the device is realized by winding at least two metallic conductor sheets or layers (B,B'), insulated by sheets or layers in dielectric insulating material (A), of which: - at least one of said metallic conductor sheets or layers (B) presents a connection on one side with an electric conductor (1); - at least one of said metallic conductor sheets or layers insulated from the previous one/s (B'), presents at least one connection with opposed electric conductor/s (3) so as to realize upon winding in coil: - a respective capacitor (4) from the first sheet (B); - a respective inductor (5) from the second sheet (B'); all of it being integrated in a sole wound device (coil). Two opposed electric connections (2,3) are advantageously foreseen in the second sheet. The dielectric insulating separator layers (A) are in 5-10 micron polypropylene sheet, but it is evident that they could also be in paper or other equivalent material. The conductor layers (B,B') are in 99.9% pure aluminium, having 5-10 micron thickness, as for the dielectric layers. SUBSTFΓUTΞ SHEET The dielectric insulating separator layers (A) and the conductor ones (B,B') wound in coil, are integrated by impregnation in epoxide resin . An electric scheme is therefore realized during operation which comprises the arrangement in series of a capacitor (4) and an inductive winding (5), all of it being on a sole coil ignition system (IB) which can be realized by coaxially applying an induced coil (IA), on the invention device (4-5) that has the integrated function of capacitance and inductance. (Figg. 4 and 5). In the Figure 4 the electrical scheme discloses the application of the invention in a traditional ignition system where (10) indicates the respective generator, for example, at 200 V; (Dl) indicates the respective charging diodes, (D2) the control grid diode, and (D3) the energy recovery diode. The respective terminals (1,2,3) integrate the device, as per the present invention, which comprises the controlled impedance (4-5-R) where the inductive component induces a rise in voltage for discharge on the plug (S) by means of the corresponding external coaxial inductor (IA). In Figure 5 the induced coil is conveniently supported by means of a plastic reel (IS), and the whole device can be resinated with epoxide resin. The solutions may naturally be varied in respect to the above, for example: - by combining sheets of metallized plastic film with metallic conductor sheets; - by combining several sheets of conductor (metallic) material with sheets of dielectric insulating (plastic) material and metallized sheets of dielectric insulating (plastic) material. Eg.: the first being a layer of metallized film (B), the second a sheet of aluminium (B') and so on; SυSSTtTUTΞ SHEET - utilizing two opposed electric conductor terminals only (1,3) on two conductor sheets or layers (B,B') which are insulated from the dielectric . (A); - pairing sheets having different lengths and/or widths; - combining these solutions with each other. SUBSTΓΓ P TΞ SHEET

Claims: CLAIMS 1. Wound capacitor-impedance device, in the form of a coil, characterized by the fact of comprising at least two metallic conductor sheets or layers (B,B') wound in a roll and electrically insulated, of which: - at least one of said metallic conductor sheets or layers (B) presents a connection on one side with an electric conductor (1); - at least one of said metallic conductor sheets or layers insulated from the previous one/s (B'), presents at least one connection with electric conductor/s on the opposite side (3) so as to realize after winding in coil of: - a respective capacitor (4) from the first sheet/layer (B); - a respective inductor (5) from the second sheet/layer (B'); all of it being integrated in a sole coil. 2. Ignition system for internal combustion motors, utilizing at least an inductor coil (IB) and at least an induced coil (IA), chara cterized by the fact that said inductor coil (IB) comprises a sheets winding of electric conductive material (B- B') wherein the respective conductive sheets or layers (B,B') are insulated (A) and electrically connected to realize further to an induct∑lnce function (5), at least an integrated capacitance function (4). 3. A device as per claim 1, characterized by the fact that the said second sheet/layer (B') presents at least two opposed conductors (2,3). 4. A device, as per claim 1, characterized by the fact that the metallic conductor sheets or layers (B,B') are separated by dielectric insulating sheets or layers (A). SUBSTIT TE HEET 5. A device as per claim 1, characterized by the fact that the metallic conductor sheets or layers (B,B') are .separated by dielectric insulating. sheets (A) in 5-10 micron polypropylene sheet. . 6. A device as per claim 1, characterized by the fact that at least one of. the conductive sheets or layers (B,B') is in aluminium. 7. A device as per claim 1, characterized by the fact that the conducive sheets or layers (B,B') and/or, the respective dielectric insulating separator material (A) are integrated in epoxide resin. 8. A device as per claim 1, characterized by the fact to be inserted in an ignition scheme (4-5-IB) connected to a low voltage generator (G), whose circuit (1,4,2,5,3) is closed by a charging diode (Dl), having control grid diode bridges (D2) and energy recovery diode (D3). 9. A device as per claim I., characterized by the fact that said conductor layers or sheets (B,B') are coplanarly spaced and insulated between dielectric insulating sheets or layers (A). 10. A device as per claim 1, characterized by the fact that it is realized by the association of metallized plastic film sheets (A) with metallic _ conductive sheets (B,B'). 11. A device as per claim 1, characterized by the fact that it comprises sheets of differing lengths and/or widths of the conductive material in respect of the non conductive material. SUSSTSTUTS SHEET

Inventors: BIONDI ASTORRE, REGAZZI GIANNI, TURA DANTE, BIONDI, ASTORRE, REGAZZI, GIANNI, TURA, DANTE
Applicants: DUCATI ENERGIA SPA, DUCATI ENERGIA S.P.A.
Application year: 1988
Main classification: H01G4
IPC codes: F02P3, H01F27, H01G4