METHOD AND HIGH VOLTAGE INCREASER DEVICE FOR I.C. COMBUSTION MOTORS

Abstract: Method and ignition device for I.C. motors with use of high voltage increaser means by means of high voltage bobbin having at least a primary winding means (Lp) and a secondary high voltage winding means (Ls), characterized in that the secondary high voltage winding means (Ls) is operated also for further increasing the respective voltage to generate ignition spark directly.

Description: Method and high voltaoe increaser device for I.C. combustion motors The present invention has for object a method and high voltage increaser device for I.C. combustion motors. The invention finds particular even if not exclusive application in the sector of the ignition systems with capacitive discharge for I.C. motors. In prior art is known that the ignitions to discharges capacitive particularly even if not exclusively for small I.C. motors, normally require a voltage on the discharging capacitor reaching hundreds of volts that normally are not available on the battery generators or accumulators that normally equip the I.C. motors of motorvehicles, I.C. stationary motors not excluded the agricultural machines in general (chainsaws, mowers, motocultivator, ecc.) To obviate these drawbacks, technical is well known the use of the high voltage increaser for increase the voltage as necessary to generate sparking. This technique requires beyond to the bobbin for high voltage connected to the ignition plug, a transformer that works to frequency more or less high for loading the to the capacitor a quantity of current that reaches the discharging capacity having at disposal a lower voltage. This transformer that is made to work at frequency more or less high is well known as "high voltage increaser". It is clear that a device of this feature is cumbersome and expensive because the assembly implicates the generator, the high voltage increaser, and the system of ignition in which the high voltage bobbin is comprised. With the present invention as per the features of the annexed claims these drawbacks are obviated by a method and ignition device for I.C. motors with use of high voltage increaser means by means of high voltage bobbin having at least a primary winding means and a secondary high voltage winding means, characterized in that the secondary high voltage winding means is operated also for further increasing the respective voltage to generate ignition spark directly. With this solution the entire device is simplified and compacted making it maximally efficient and producible at very low costs. Advantageously the function of further increasing the voltage to the high voltage bobbin is realized by means of a high voltage stopping diode, set between the primary/s winding/s and the secondary/s winding/s in order that: - in a first phase to allow to the current to flow from the secondary winding toward the capacitive system; - and in a successive phase to prevent this this current to flow, the stopping diode being polarized inversely, constraining the current via hearth to determine the discharge in the ignition plug . With this solution making further more efficient and safe in the actuation the respective device . In a further preferred solution the device comprises the integration with the primary winding of the discharging capacity by means of a capacitor winded element with controlled impedance, of the type having a bobbin coaxial with the secondary winding, said windings being realized utilizing electric conductor sheets or layers alternated with dielectric insulating sheets or layers, in which in at least two of said winded electric conductor sheets or layers, is elicit respective couples of opposite terminals electric connections, constituting the primary winding in order to include in it also the capacitive function. These and other advantages will appear from the successive specified description of preferential solutions of realization with the help of the included drawings which particulars of execution are not to be considered limitative but only exemplificative. Figure 1 represents a view of an electric schema realizing the invention in preferred solution utilizing an integrated device of inductance and capacity. Figure 2 represents a view of an alternative solution without utilizing the integrated device of inductance and capacity disclosed in figure 1. Figure 3 represents the respective diagram of actuation in the phase of loading the capacity {lp-t (current intensity/time, on the system of primary winding)} and {Vc-t (voltage/time on the capacity)}. Figure 4 represents the development of the respective sheets of the integrated element of inductance and utilized capacity in the schema of Figure 1. Figure 5 represents a schema of the entire device comprising the primary winding and secondary winding where the primary is an inductance and capacity integrated device disclosed in Figure 1 with ferromagnetic soul. In figure 5 the ferromagnetic soul is schematized as central coaxial element (M), while the integrated primary winding bobbin is indicated with Lp respectively with (ALp), the secondary winding bobbin being indicate with (Ls). The integrated primary winding bobbin as shown in figures 1 - 4 - 5 is composed of metallic conductive sheets (Lp) insulated by dielectric foils (Ad). All the sheets/foils are winded in bobbin as indicated in Figure 5 and these conductors ( generally in aluminium ) present four connection electric terminals 1 ,2,3,4. In figure 1 is disclosed that with (ALp) is indicated (included in dotted line) the device that includes the integration with the primary winding element (Lp) that comprises the inductive function and the capacitive function (indicated with C), being the respective four terminals (1 - 2, 3 - 4) connected: - the first terminal (1 ) with path function of the current flow indicated with lp by an output diode from generator (D1 ) placed between the generator (GEN) and the terminal (1 ); - the second terminal (2) hearth connected through electronic breaker that implicates periodical off/on actions (S) as for example a transistor or a "MOSFET", with connected bridge to the anode (A) of an SCR (or other static breaker) which GATE (G) is controlled by a control device (10), ( Eg .pick-up or other equivalent device), able to generate a signal of command of the SCR in an opportune moment; - the third terminal (3) connected to the cathode (K) of said SCR; - the fourth terminal (4), connected to earth by means of diode (D4) and bridged by means of recirculation diode (D2) with the power line supplying current to the secondary winding element (Ls) and plug (Cd) with the intermediation of a high voltage diode (D3) that presents the cathode also connected to the cathode of the recirculation diode (D2) and further connected to the cathode of the generator output diode (D1 ). Making reference to Figure 2 the integrated system (ALp) is substituted by means of traditional which means that have: - a power line, from the generator (GEN) through generator output diode (D1 ): - with a first branch by means of diode for high voltage (D3) with cathode connected to the cathode of said generator output diode (D1), that connects to the secondary winding (Ls) and to the plug (Cd); - with a second branch that is connected to a primary winding (Lp) which opposite terminal is connectabie to earth by means of electronic switch that implicates periodical on/off actions (S) as for example a bipolar transistor or a "MOSFET", with bridge by means of a connection to the anode (A) of an SCR, which GATE (G) is controlled by means of control device (10); - with a third branch, intercepted by a diode (D4) with cathode to earth, being foreseen the connection with the intermediation of a capacitor (C) bridged by diode (D2), which cathode is in connection with the cathode of the generator output diode (D1 ). The actuation can be divided in two distinguished phases: A) loading of the capacity "C" to the voltage Vc B) discharge of the capacity "C" with generation of the spark in the ignition plug Cd. A) In this phase the charge of the capacity happens through the periodical openings and closures of "S" (that consists as said in an electronic switch which bipolar transistor or Mosfet or others electronic devices opportunely actuated), with a frequency more or equal to the discharging frequency in the ignition plug. At the closure of "S" the current "lp" flows from the generator (accumulators battery or other generator at low voltage) through the generator output diode (D1) to the terminations (1) and (2) of the winded sheet of the capacitor winded element for controlled impedance (that act as as a inductor (Lp Fig.1) {or by the primary inductance (Lp) in Fig.2} and the switch "S" that is closed; the current (lp) flows as by Fig.3 (to - t1 ; t2 - t3; ), until opens "S", (t1 - t2; t3 - t4; ), being (Ls) magnetically coupled with (Lp), being two coaxial windings with central nucleus of ferromagnetic material (M), the brusque current variation in the primary winding (Lp) generates an high potential in the secondary winding (Ls) that polarizes directly the high voltage stopping diode (D3) and the diode (D4) allowing a current circulation by (Ls, D3,1 ,C,4,D4) Fig.1 and (Ls,D3,C,D4) Fig.2, that loads the capacity "C" to levels progressively crescent (V1 ,V2,V3 ), preventing that the voltage on (Ls) increases beyond the consented values when the instant of sparks is not happening. The process repeats until when the voltage "Vc" on the capacity "C" reaches the desired value (see Fig.3). Said voltage value (Vc) is obtained for example by means of control of the frequency of the electronic breaker (S). B) the discharge phase of the capacity "C" and so of sparks, is commanded from the command device (10) able to generate a signal of command in an opportune instant for the SCR or other static or not static instructor equivalent, that determines the ignition instant. After that the device (10) had given the signal on the "GATE" G of the SCR the contained energy in the capacitor "C" transfers on the primary inductance "Lp" and the current flows from the anode to the cathode of the SCR and so the path is (C,2,SCR,3) Fig.1 ,; (C,Lp,SCR) Fig.2, until it reaches its maximum value after of that, the current continues to flow in the same sense with path (2,SCR,3,4,D2 > 1 ) Fig.1 ; (Lp,SCR,D2) Fig.2 until exhaustion of the energy, having so an unidirectional discharge. The secondary winding (Ls) being magnetically coupled with (Lp) and having a inductive value very high if compared to (Lp) is seat of an electromotive induced force from the current variation on (Lp) that polarizes inversely the high voltage stopping diode (D3) and with such a value to prime the spark on the ignition plug (Cd).

Claims: Claims 1 . Method and ignition device for I.C. motors with use of high voltage increaser means by means of high voltage bobbin having at least a primary winding means (Lp) and a secondary high voltage winding means (Ls), characterized in that the secondary high voltage winding means (Ls) is operated also for further increasing the respective voltage to generate ignition spark directly. 2. Method and ignition device as claimed in claim 1 ., characterized in that the function of further increasing the voltage to the high voltage bobbin is made by means of a high voltage stopping diode (D3), placing it between the primary/s winding/s (Lp) and the secondary/s winding/s (Ls). 3. Method and ignition device as claimed in claim 1., characterized in that the device comprises the integration with the primary winding of the discharging capacity by means of the use of a capacitor winded element (ALp) with controlled impedance, of the type comprising a coaxial bobbin to the secondary winding, with electric conductors sheet/s or layer/s (Lp) integrated by dielectric insulating foil/s or iayer/s ( for ) , in which in at least two of said sheet/s or foil/s or layer/s winded conductors (Lp) is elicited respective couples of opposite terminal connections (1 ,2,3,4), constituting the primary winding (Lp/ALP) that includes in it also the capacitive function. 4. Ignition device as claimed in claim 1., characterized in that it comprises the integration with the primary winding (Lp) of the inductive and capacitive (C) function, being the respective four terminals (1 -2, 3-4) connected: - the first terminal (1 ) with path function of the current flow (lp) by an output diode from generator (D1) placed between the generator (GEN) and the terminal (1 ); - the second terminal (2) hearth connected through electronic breaker that implicates periodical off/on actions (S) as for example a transistor or a "MOSFET" , with connected bridge to the anode (A) of an SCR (or other static breaker) which GATE (G) is controlled by a control device (10), able to generate a signal of command of the SCR in an opportune moment; - the third terminal (3) connected to the cathode (K) of said SCR; - the fourth terminal (4), connected to earth by means of diode (D4) and bridged by means of recirculation diode (D2) with the power line supplying current to the secondary winding element (Ls) and plug (Cd) with the intermediation of a high voltage diode (D3) that presents the cathode also connected to the cathode of the recirculation diode (D2) and further connected to the cathode of the generator output diode (D1). 5. Ignition device as claimed in claim 1., characterized in that it comprises: - a power line, from the generator (GEN) through generator output diode (D1 ): - with a first branch by means of diode for high voltage (D3) with cathode connected to the cathode of said generator output diode (D1 ), that connects to the secondary winding (Ls) and to the plug (Cd); - with a second branch that is connected to a primary winding (Lp) which opposite terminal is connectabie to earth by means of electronic switch that implicates periodical on/off actions (S) as for example a bipolar transistor or a "MOSFET" , with bridge by means of a connection to the anode (A) of an SCR, which GATE (G) is controlled by means of control device (10); - with a third branch, intercepted by a diode (D4) with cathode to earth, being foreseen the connection with the intermediation of a capacitor (C) bridged by diode (D2), which cathode is in connection with the cathode of the generator output diode (D1 ). 6. ignition Method second the claim 1., characterized in that of comprising the following operative phases: - loads of a capacity "C" to a voltage Vc by means of periodical openings and closures (on/off) of an electronic breaker "S", with a frequency more or at least equal to the frequency of discharges in the ignition plug, in order that for interruption, the current (lp) flow from the generator through a generator output diode (D1 ) to the terminations of the primary inductance (ALp/Lp) and then increases (to-t1 ; t2-t3;...), until said breaker (S) opens (t1 -t2; t3- t4;....), in order that the brusque current variation in the primary winding (Lp) genders an high potential in the secondary winding (Ls) that polarizes directly an high voltage stopping diode (D3) being foreseen the control of the circulation of the current by means of a hearth diode (D4), in order that in the space-time capacity "C" is charged to levels progressively crescent (V1 ,V2,V3....), preventing that the voltage on secondary winding (Ls) increases beyond the consented values when the spark instant do not happens and repeating the process until the desired voltage "Vc" on the capacity "C" is reached. - discharging of the capacity "C" with generation of the spark in the ignition plug (Cd) by means of an emitted frequency (D4) to a command device (10) able to generate a command signal in an opportune instant for an SCR or other switch equivalent able to cause the ignition instant.

Inventors: BIONDI ASTORRE, REGAZZI GIANNI, BIONDI, ASTORRE, REGAZZI, GIANNI
Applicants: DUCATI ENERGIA SPA, DUCATI ENERGIA S.P.A.
Application year: 1990
Main classification: F02P3
IPC codes: F02P1, F02P3, F02P9, H01F38