EP0042343A1 - Volant magnétique d'allumage pour moteur thermique - Google Patents

Volant magnétique d'allumage pour moteur thermique Download PDF

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Publication number
EP0042343A1
EP0042343A1 EP81400955A EP81400955A EP0042343A1 EP 0042343 A1 EP0042343 A1 EP 0042343A1 EP 81400955 A EP81400955 A EP 81400955A EP 81400955 A EP81400955 A EP 81400955A EP 0042343 A1 EP0042343 A1 EP 0042343A1
Authority
EP
European Patent Office
Prior art keywords
magnetic
strip
sensor
plastoferrite
bell
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP81400955A
Other languages
German (de)
English (en)
French (fr)
Inventor
Gastone Dell'aglio
Roberto Mancini
Marc Bonnet
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Peugeot Cycles SA
Plessey SpA Dite Ste
Original Assignee
Peugeot Cycles SA
Plessey SpA Dite Ste
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Peugeot Cycles SA, Plessey SpA Dite Ste filed Critical Peugeot Cycles SA
Publication of EP0042343A1 publication Critical patent/EP0042343A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
    • F02P1/00—Installations having electric ignition energy generated by magneto- or dynamo- electric generators without subsequent storage
    • F02P1/02—Installations having electric ignition energy generated by magneto- or dynamo- electric generators without subsequent storage the generator rotor being characterised by forming part of the engine flywheel

Definitions

  • the present invention relates to an electromagnetic device for a magnetic flywheel, in particular for mopeds.
  • a soft iron bell containing the polarized element constituted by a plastoferrite strip, that is to say a magnet made of plastic, ceramic or similar material, which is stuck to the 'inside the periphery of said bell (which constitutes the rotor), and a stack of soft iron, silicon iron or other, constituting the stator and carrying the windings in copper wire current generators.
  • a device is usually used to generate the electric current necessary for the ignition systems and the accessories which are usually provided on mopeds comprising a two-stroke or four-stroke internal combustion engine.
  • the device can also be combined with an angular position sensor.
  • the rotor is normally keyed onto the drive shaft and it also performs the function of rotating mass stabilizing the operation of the motor, that is to say the function of a flywheel.
  • the plastoferrite strip that is to say the plastic magnet, is polarized in the radial direction with alternating poles in a variable number, two, four or more depending on the energy required for the. device.
  • a cam is usually provided for the ignition device, which is integral with the bell forming the rotor, and which cuts by means of two contacts the current flowing in one or more of the stator windings the corresponding variation in flux inducing in the an appropriate of these secondary windings, an overvoltage which is used for the ignition of the mixture in the cylinder.
  • the contacts are open and are closed by the cam when the value of the current in the winding is zero; said contacts being opened again when this current reaches its maximum value. This is intended to prevent the passage of current through the winding even when it is not necessary (which is a problem which arises only in polarized flywheels having more than two poles, i.e. four poles or more).
  • Another ignition system called a capacitive discharge device, consists in charging a capacitor by means of a voltage coming from a winding and in discharging this capacitor in the primary of a transformer at a certain suitable time. This moment is usually close to the top dead center of the stroke of the engine piston, and it is at this precise moment that a "trigger" pulse is necessary to control the electronic discharge circuit.
  • This trigger pulse is generated by a sensor which uses special magnetic combinations in the steering wheel.
  • a polarized sensor and a system are used to temporarily close the magnetic field by means of an internal or external cam.
  • the signal has no relation with the magnets of the bell and it is only a function of the variation and the speed of variation of the magnetic flux induced in the current generating winding of the magnetic flywheel through the cam.
  • Other devices which include sensors which use the same poles of the flywheel forming the rotor. These devices are called non-polarized sensors and operate on the principle of the differential transducer, that is to say that they comprise (FIG. 1) two branches A, B of a magnetic circuit having respective windings VA and VB, tensions on these windings being proportional to the variations in the respective fluxes. Normally, to obtain a cancellation of the fluxes generated by the magnets of the alternator, the windings are connected in opposition and therefore, when equal fluxes are supplied by the poles S1, N1, S2 and N2, the two voltages in the windings VA and VB cancel each other and the electrical signal is zero.
  • plastoferrite flywheels i.e. plastic magnets
  • the plastoferrite band P is placed against the edge of the bell C. iron; on the inner surface of the P-band plastofer - rite polarized areas facing the air gap are formed by magnetization.
  • P iron segments SG shaped so as to concentrate the field and to produce the abovementioned discontinuity by means of appendices P11 and P12 offset having a function similar to that of appendices P1 and P2.
  • the SG segments are expensive in terms of their manufacture and their application, and constitute an obstacle or a difficulty which increases the air gap and reduces the possibility of exploiting the whole of the available space.
  • the object of the invention is to avoid the drawbacks of the aforementioned devices which involve relatively high manufacturing costs and to solve the problem posed by using the plastoferrite ring, that is to say the plastic like , but avoiding the application of the GS metal plates on the plastoferrite ring by rivets and / or gluing, which are very expensive operations.
  • the invention consists in the fundamental concept that operation is possible provided that one of the two flows 0 A is different from the other ⁇ B only at a point on the circumference of the flywheel, while it is not it is not necessary that one of the flows is equal and of opposite direction to the other, but that it is enough that it is different. In particular, it is sufficient to ensure that one of the two flows ⁇ A and ⁇ B is zero independently of the other, which can be kept constant.
  • the subject of the invention is therefore a magnetic flywheel for an endothermic engine, for a motor vehicle and the like, of the type comprising a bell and inside thereof a magnetic strip of plastoferrite, or of ceramic or similar material, which cooperates with an armature or star rotor for induction windings and with an electromagnetic angular position sensor comprising two magnetic branches connected to opposing windings and adapted to generate a signal as a result of an imbalance.
  • a discontinuity is provided in the strip of plastoferrite or similar material, capable of modifying the magnetic flux in only one of the two branches of the cap. tor.
  • the plastoferrite or similar material can be removed so as to make a notch over its entire thickness or in any case a significant increase in the air gap.
  • the discontinuity thus formed can also be obtained by closing the magnetic circuit on the bell by means of a metal tab forming part of the bell and folded in a cavity of the plastoferrite strip along the surface of the air gap.
  • the discontinuity of the strip is advantageously made so as to correspond to a transition between two poles.
  • the discontinuity can also be provided so as to correspond to a pole.
  • reference 11 designates the iron bell, which rotates normally and which also serves as a flywheel.
  • the reference 13 designates the plastoferrite strip, that is to say the plastic magnet, which is fixed inside the bell and is magnetized as shown in Fig.5 to cooperate with the poles 15 d 'a fixed armature on which the windings 17 are wound.
  • a sensor 19 is mounted in place of one of the poles 15 and comprises two branches 19A and 19B on which are mounted windings VA and VB which are connected in opposition to each other. Under normal conditions, the two branches 19A and 19B are crossed by two concordant flows as indicated in FIGS.
  • the magnetic potential is brought to zero at the point opposite the branch 19A by means of a metal tab 11B which is formed by stamping or other deformation of the bell 11, tab which is brought into a recess 13B of the plastoferrite 13.
  • a metal tab 11B which is formed by stamping or other deformation of the bell 11, tab which is brought into a recess 13B of the plastoferrite 13.
  • the most economical method to obtain the desired conditions consists in removing the magnetic material at a point corresponding to the sensor as indicated in Fig.7 to 9. _
  • the voltage induced in a winding of a plastoferrite magnetic flywheel is of the type shown in Fig. 11.
  • the tension is not sinusoidal while presenting ridges.
  • the Fourier series decomposition of the signal provides a third order harmonic component due to the magnetic distribution of the polarization.
  • the frequency of such a voltage is, in the case of a six-pole flywheel, three times the main frequency of the device.
  • the signal to be obtained is shown diagrammatically in Fig. 12 in which Ti is the induced voltage and Pu is the signal from the sensor.
  • the voltages in the windings VA and VB are those indicated in Fig. 13; a drop in the induced voltage occurs in the presence of the notch 13A (in this case formed at a point corresponding to the transition between two poles) due to a lack of magnetic field as indicated in Vx, thus producing the desired signal Seen.
  • the notch 13A can also be formed in the symmetrical part of the strip, that is to say towards the outside of the bell rather than towards the inside as re present.
  • Fig.14 is an electrical circuit diagram associated with the windings VA and VB in the above example, R L indicating in this circuit a load resistance.
  • the magnetized mass can be made of ceramic material whose shape with the part removed or the recessed area can be obtained during manufacture.
  • discontinuity provided in the strip can also be arranged to correspond to a pole rather than to correspond to the transition between two poles.
  • FIGS. 15 and 16 show the arrangement of a sensor 119 with respect to the magnetic strip 113, the latter being in turn disposed inside a bell 111 of a rotor.
  • a plate 114 which is fixed to the core 115 of the stator and adapted to carry the sensor 119 covers the entire sensor and extends so as to constitute a screen delimiting an air gap at its end with the magnetic strip 113, which is equal to that which constitutes the core of the sensor with the strip 113.
  • the strip 113 has a. of course 113 A.
  • Fig.17 is a developed view of the magnetic strip 113 comprising polar zones designated alternately by N and S and separated by interpolar zones designated by A, B, C and D having leakage flows ⁇ f.
  • These flows ⁇ f give rise to deformations in the distribution of the main flow and these deformations cause disturbances in the operation of the sensor, which cause spurious signals which can adversely affect the electronic device connected downstream.
  • the particular function of the magnetic screen is that of short-circuiting these different leakage flows as a result of eliminating the output signal from the sensor of parasitic alterations which are otherwise difficult to filter without altering the signal. useful.
  • Fig.18 shows a particular embodiment of a magnetic flywheel comprising the sensor, in a casing of a heat engine.
  • This Fig. comprises the same members as shown in Fig.15 and further an element 116 of the motor housing usually made of cast aluminum, and a cover 118 to protect the magnetic flywheel.
  • the function of the magnetic screen 114 therefore consists in deviating flux ⁇ p in an appropriate manner to prevent it from affecting the operation of the sensor.
  • Fig. 19 contains the same elements as the example in Fig. 15, with the difference that the plate 114 is extended up to 114 B to laterally protect the strip 113, forming with it an air gap and making the fluxes of leakage ⁇ f in order to prevent them from disturbing the sensor 119.
  • Fig.20 shows the notch 13A formed in the magnetic strip 13 over half the height of this strip, to affect only one of the branches of the sensor 19.
  • This notch is located between an end of the North pole (or South ) and half of the next interpolar zone IT, fc indicating the direction of movement of the notch 13A in front of the ends of the branches 19A and 19B of the sensor.
  • Fig.21 schematically shows the distribution of ⁇ B and ⁇ A flows in each branch 19B and 19A of the sensor.
  • the upper curve shows the normal variation of the flow in branch 19B from + ⁇ B to - ⁇ B.
  • the lower curve shows the flow in the branch 19A of the sensor in front of which the notch 13A moves.
  • branch 19A the flux varies rapidly from a value + ⁇ A (in PI) to O (in P2), while at the same time the flux ⁇ B decreases very little from + ⁇ B.
  • the imbalance of the flow between the two branches 19A and 19B of the sensor is the highest.
  • the fact of positioning the notch at the end of a pole makes it possible to remove only a very small all of the active material, which does not cause any disturbance in the rest of the operation of the magnetic flywheel.
  • the dimension of the notch 13A in the relative direction of movement is preferably greater than the corresponding dimension of the ends of the branches 19A and 19B of the sensor 19.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Ignition Installations For Internal Combustion Engines (AREA)
  • Permanent Magnet Type Synchronous Machine (AREA)
EP81400955A 1980-06-16 1981-06-16 Volant magnétique d'allumage pour moteur thermique Withdrawn EP0042343A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT09467/80A IT1133580B (it) 1980-06-16 1980-06-16 Captatore elettromagentico del l'angolo do fase per volani-magnete impieganti 'plastoferrite' quale elemento polarizzato
IT946780 1980-06-16

Publications (1)

Publication Number Publication Date
EP0042343A1 true EP0042343A1 (fr) 1981-12-23

Family

ID=11130573

Family Applications (1)

Application Number Title Priority Date Filing Date
EP81400955A Withdrawn EP0042343A1 (fr) 1980-06-16 1981-06-16 Volant magnétique d'allumage pour moteur thermique

Country Status (4)

Country Link
EP (1) EP0042343A1 (it)
JP (1) JPS5731364A (it)
ES (1) ES8203538A1 (it)
IT (1) IT1133580B (it)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0305670A2 (en) * 1987-08-28 1989-03-08 DUCATI ENERGIA S.p.A. Flywheel generator with improved ignition pilot device
CN110870179A (zh) * 2017-07-12 2020-03-06 斯堪尼亚商用车有限公司 车辆推进系统

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3105481A (en) * 1961-12-14 1963-10-01 Onan Division Of Studebaker Pa Ignition system
FR1369469A (fr) * 1963-07-02 1964-08-14 Motobecane Ateliers Perfectionnements apportés aux dispositifs d'allumage électronique des moteurs à combustion interne
US3775627A (en) * 1971-04-28 1973-11-27 Nippon Denso Co Ignition timing signal generator
US3821571A (en) * 1972-04-17 1974-06-28 Mitsubishi Electric Corp Flywheel magneto

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3105481A (en) * 1961-12-14 1963-10-01 Onan Division Of Studebaker Pa Ignition system
FR1369469A (fr) * 1963-07-02 1964-08-14 Motobecane Ateliers Perfectionnements apportés aux dispositifs d'allumage électronique des moteurs à combustion interne
US3775627A (en) * 1971-04-28 1973-11-27 Nippon Denso Co Ignition timing signal generator
US3821571A (en) * 1972-04-17 1974-06-28 Mitsubishi Electric Corp Flywheel magneto

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0305670A2 (en) * 1987-08-28 1989-03-08 DUCATI ENERGIA S.p.A. Flywheel generator with improved ignition pilot device
EP0305670A3 (en) * 1987-08-28 1989-03-29 Ducati Energia S.P.A. Flywheel generator with improved ignition pilot device
CN110870179A (zh) * 2017-07-12 2020-03-06 斯堪尼亚商用车有限公司 车辆推进系统

Also Published As

Publication number Publication date
IT1133580B (it) 1986-07-09
ES503065A0 (es) 1982-04-01
IT8009467A0 (it) 1980-06-16
ES8203538A1 (es) 1982-05-16
JPS5731364A (en) 1982-02-19

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Inventor name: BONNET, MARC

Inventor name: MANCINI ROBERTO

Inventor name: DELL'AGLIO GASTONE