WO1992000453A1

WO1992000453A1 - Generator with power-supply system for electronic ignitions

Info

Publication number: WO1992000453A1
Application number: PCT/IT1991/000015
Authority: WO
Inventors: Gianni Regazzi; Astorre Biondi; Lorenzo Fiorini
Original assignee: Ducati Energia SpA
Current assignee: Ducati Energia SpA
Priority date: 1990-06-28
Filing date: 1991-03-05
Publication date: 1992-01-09
Anticipated expiration: 1992-12-28
Also published as: IT9083417A0; IT1245634B; AU7449791A; IT9083417A1

Abstract

A generator for internal combustion engines to command and power-supply the ignition circuit, of the type with stellar internal stator (T) having statoric coils-bobbins in respective radial axis (breeds/rays 2-3) for electric energy generation by means of induction and a rotor endowed with permanent magnetic poles (R) that influence magnetically the aforementioned coils-bobbins (2-3), in which at least one of said coils-bobbins (2) has the function of power-supply and/or command of an electronic ignition circuit, characterized in that said rotor (R) has at least two rotor magnetic poles between them adjacent, magnetized with the same polarity (N-N or S-S) or has a greater rotor extension magnetic pole if compared to the others, to influence in different way said coil/s-bobbin/s for power-supply and/or command of the ignition (2) if compared to the other coils-bobbins (3).

Description

Generator with power-supplv system for electronic ignitions.

The present invention concerns a magneto-permanent fly-wheel rotary generator with power-supply system for the electronic ignition in internal combustion engines particularly two-stroke engines cycle "OTTO" of small size and preferably motorcycles, mopeds and similar engines, not excluded the small engines and portable engine-tools.

In this generators when we need high power at lower rotation regimes we prefer to use multipolar generators with 10,12 and more poles. Normally 1 ,2 and more breeds (rays) of the statoric laminate core are used for the power-supply to the electronic ignition system of the endothermic engine whereas the remaining are used for the power-supply to the auxiliary services (lights, battery recharge, ecc). As the available power, for each of the statoric breeds pledged for the supply to the ignition system, is particularly exuberant for the ignition, for not affecting the operation of the ignition we are obliged to limit the power supplied at high rotation regimes by means of particular artifices as short- circuit spires and/or other contrivances that are however of complex assembly , expensive and present usual important thermic problems. Furthermore these solutions need a phase captor device (pick-up = ignition pilot coil) for the command of the electronic ignition.

n fact the use of an electronic ignition device preferably with capacitive discharge from a coil situated into the internal of the same generator, able to give the charge of the respective capacitor and the command of the ignition function, is limited to 4-pole generators where we have two sparks per revolution dephased of 180°. This particularity is completely automatic, even if not whished, because it is function of the number of the magnetic poles and of their placement into the internal of the same generator, this means that for endothermic engines, the not utilized spark contributes to the thermic increasing of the ignition function, drastically reducing the electric efficiency.

The present solution allows to use an electronic ignition preferably with capacitive discharge that uses the power-supply coil also as command of the electronic ignition circuit with multipolar fly-generators, being the number of poles preferably 6 or more, generating a sole spark for revolution or only if wished, more sparks per revolution, in dependence of the magnetization of the rotor eliminating so the presence of the phase captor and of expensive artifices for the limitation of the power supplied which are for example the spires of short circuit.

The invention, consists as claimed in a generator for internal combustion engines to command and power-supply the ignition circuit, of the type with stellar internal stator having statoric coils (bobbins) in respective radial axis (breeds/rays) for electric energy generation by means of induction and a rotor endowed with permanent magnetic poles that influence magnetically the aforementioned coils -bobbins, in which at least one of said coils-bobbins has the function of power-supply and/or command of an electronic ignition circuit, characterized in that said rotor presents at least two rotor magnetic poles between them adjacent, magnetized with the same polarity (N-N or S- S) or presents a greater rotor extension magnetic pole if compared to the others, to influence in different way said coil/s-bobbin/s for power-supply and/or command of the ignition (2) if compared to the other coils-bobbins (3) . With this solution we strongly simplifie the ignition apparatus and we reduce its encumber and the cost of the phase captor (Pick-Up), and we obviate to the complex limitation of the power supplied.

It is however possible to use this system in coupling with a phase captor using the supply bobbin only as recharge of the ignition capacitor. In describing the operation for example we make reference to a fly-wheel rotary generator 12 poles , obviously the number of poles may change.

Figs. 1a, 1b, 1c and 1d disclose 12 poles fly-wheel generator, with one spark per revolution command to the electronic ignition by means of a statoric coil-bobbin extension core that short-circuit magnetically two rotor magnetic poles between them adjacent. Figs. 2a, 2b, 2c and 2d represent the operation principle of a fly-wheel generator as from the Figures 1.... but in which two statoric coil-bobbin extension cores , able to give the supply and/or the command of the ignition, are extended to cover each-one only one rotor magnetic pole operating in this case on the coil systems of the respective spires of the statoric magnetic adjacent coil-bobbin extension cores to obtain the identical functional effect of the single statoric coil-bobbin extension core which form, position and geometric size is such to short-circuit two rotor magnetic poles between them adjacent. As previously described (coils in series and in the same spiral coil sense). Figures 4,6 represent alternative solutions to the solutions of Figures 1... with statoric coil-bobbin extension core that short-circuit magnetically two rotor poles North-South between them adjacent being Figure 4 with magnetic "plastoferrite" ring sectorially continuously magnetized while Figure 6 represents a form with separate permanent magneto sectors. Figure 5 shows a particular rotor magnetization that allows to obtain two sparks for revolution. Figure 3 represents a schematic behavior diagram of the tension (voltage) to the ends of the supply bobbin and/or electronic ignition command according to invention and with rotor magnetization according to Figure 1. Figure 7 and 8 represent electric operation utilizing ignition schemas according to this invention. In the Figures 1 ,4 the statoric coil-bobbin core extension which bobbin gives the power-supply and/or the command of the ignition is of shape, position and geometric size (1) such to short-circuit magnetically two rotor magnetic poles and the rotor magnetization presents three poles between them adjacent with the same magnetic polarity.

Referring to the Figs. 1a, 1b, 1c, 1d we note that, because the particular form of the statoric coil-bobbin core extension which bobbin gives the powe- supply and/or the command of the ignition, only when the rotor passes from the position that invests the South North poles (Fig.1a N-S) to the position that invests the poles North-North (Fig.lb N-N), a potential difference to the ends of the supply bobbin is generated, while when the rotor passes from a position that invests the poles North-North (Fig.lc N-N) to the position that invests the poles South-North (Fig.ld S-N) we have equally the generation of a potential difference to the ends of the supply bobbin but of opposite polarity. In all the other positions of the rotor we have not electric potential generation on the supply bobbin and/or command of the ignition circuit because the rotor magnetic poles are covered and shortcircuited by the statoric coil-bobbin core extension (1) of the supply bobbin and/or ignition command (2) while the low-tension coils (3) are not influenced from the particular form of the supply bobbin. The path of the potential difference at the ends of the supply bobbin and/or ignition command (2) is visible in fig.3 provided that the rotor magnetization is that of Figure 1 , where we note and can use one of the two semiwaves (4 or 5) for the charge of the capacitor and the other (5 or 4) for the command of the ignition, obtaining in this way the spark when is necessary and in the case indicated, one spark per revolution.

A functionally identical result is obtained with the solution of figs..2a, 2b, 2c, 2d in which the supply bobbins of the ignition are two of analog sizes (1'-2) to those of low tension (3) but wound both in the same sense of winding (2) while the rotor magnetization is equal to that previously described fig.2. Being the two supply bobbins in series between them but wound in the same sense of winding , normally the tensions of the two bobbins are in phase opposition and we have a compensation. Only when the rotor rotates from position of Figure 2a to position of Figure 2b a potential difference to the ends of the two supply bobbins and an opposite polarity potential difference is generated when the rotor rotates from the position of Figure 2c to the position of Figure 2d obtaining a tension to the ends of the two supply bobbins as from fig.3 provided that the rotor magnetization is that of the Figures 1 and 2, having so an ensemble result equal to that of the previous solution with statoric shape, position and geometric size pole, such to short-circuit two rotor magnetic poles.

The solutions described remains functionally identical if we utilize a rotor having a continuous magnetic ring (plastoferrite for example) magnetized in sectors North-South or viceversa (see fig.4). A solution that allows two sparks per revolution is visible in fig .5 while in fig.6 is visible another type of magnetization that allows always one spark per revolution to obtain electronic ignition without phase captor.

The electric power supplied to the ignition system is limited in that it is supplied with only one capacitor charge impulse in correspondence of the ignition function and we do not need to short-circuit spires or other artifices to limit the charge of the capacitor of the ignition system with all the benefits that derive, both of thermic view point and of constructive simplicity.

The present solution can furthermore be used in coupling with one phase captor (pick-up) in this case the fly-wheel rotary generator gives to the ignition circuit exclusively the charge of the capacitor and not the command of the ignition that in the specific exceptional case, is supplied by the relative phase captor (Pic-Up). Figures 7 and 8 disclose two circuital solutions, fundamentally identical with the sole difference that in Figure 8 is used an inductive-capacitor bobbin with controlled impedance that involves conductive metallic sheets insulated with dielectric sheets/layers to form inductance (Lp) as primary coil and contemporary capacitor (C1). In said solutions the power-supply bobbin and/or command of the ignition is indicated with 2. During the positive half-wave (4) of the tension of the supply bobbin and/or command of the ignition, the diode D3 is polarized inversely while the diodes D1 , D2, D4 are polarized directly so the electric current flows from the power-supply bobbin across D1 , C1 , D4, D2 loading C1 with a certain potential. When the potential of the supply bobbin reverses its own polarity sign, the diodes D1 ,D2,D4 are polarized inversely while D3 is polarized directly and the current flows across R3, C2, R1 , D3 and in small part also across R2, provided that the potential of the power-supply bobbin overcomes the potential of C2 that have been previously loaded.

We remember that the solution is particularly efficient from an energetic point of view for the charge of C1 because the electric circuit part composed by R1 , R2, R3, C2, D2, D3 realizes a branch with high impedance and consequently limits strongly the current circulation during this phase, in practical the supply bobbin during the command phase of the SCR does not work (free work).

The particular circuital configuration of the thyristor (SCR = Silicon Controlled Rectifier) piloted from the cathode with the gate directly to mass allows its priming when the current of the supply bobbin flows on R3 entering from mass and causes a fallen of potential greater than the threshold priming tension of the SCR. At this point the priming of the SCR allows the discharge of the capacity C1 on the primary coil Lp with the consequent transferring of energy to the secondary coil Ls where a high potential is inducted such to prime a spark on the ignition plug Ca which current can close across the diode D2 while the current of the primary coil Lp closes on the diode D4 or D4, D5 in the case we utilize the said inductane-capacitor bobbin with controlled impedance referenced in Figure 8. The circuital configuration composed by R2, C2, R1 , D3 is to realize a peak detector and is this particular solution that allows to manage the path of the ignition phase intervening on the resistive values R1 , R2 or on the value of the capacity C2.

Claims

Claims 1. A generator for internal combustion engines to command and power-supply the ignition circuit, of the type with stellar internal stator (T) having statoric coils-bobbins in respective radial axis (breeds/rays 2-3) for electric energy generation by means of induction and a rotor endowed with permanent magnetic poles (R) that influence magnetically the aforementioned coils-bobbins (2-3), in which at least one of said coils-bobbins (2) has the function of power-supply and/or command of an electronic ignition circuit, characterized in that said rotor (R) has at least two rotor magnetic poles between them adjacent, magnetized with the same polarity (N-N or S-S) or has a greater rotor extension magnetic pole if compared to the others, to influence in different way said coil/s-bobbin/s for power-supply and/or command of the ignition (2) if compared to the other coils-bobbins (3).

2. A generator according to claim 1., characterized in that said stator (T) has at least one statoric coil-bobbin/core extension (1) which form, position and geometric size is such to short-circuit magnetically two rotor magnetic poles when these are of opposite polarity (N-S or S-N) while when these are of equal polarity (N-N or S-S) is magnetically influenced in order to generate an electric signal for the power supply and/or command of the ignition.

3. A generator according to claim 1., characterized in that said stator (T) has at least two adjacent statoric coil-bobbin/core extensions (1") with coils electrically connected in series with the same sense of winding in order to discharge an electric signal when they are influenced by the passage from rotor magnetic poles of opposite polarity (N-S or S-N) to rotor magnetic poles of equal polarity (N-N or S-S) or viceversa.

4. A generator according to claim 1 , characterized in that it is coupled with one electronic ignition circuit with capacitive discharge to obtain one or more sparks per revolution without phase captor.

5. A generator as claimed in claim 1 , characterized in that it is coupled with one inductive electronic ignition circuit to obtain one or more sparks per revolution.