EP1254313A2

EP1254313A2 - Method for producing a sequence of high-voltage ignition sparks and high-voltage ignition device

Info

Publication number: EP1254313A2
Application number: EP01903597A
Authority: EP
Inventors: Manfred Vogel; Werner Herden
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2000-01-26
Filing date: 2001-01-08
Publication date: 2002-11-06
Anticipated expiration: 2021-01-08
Also published as: DE10003109A1; US20030089355A1; DE50100351D1; WO2001055588A3; US6666195B2; EP1254313B1; JP2003521619A; RU2268394C2; WO2001055588A2

Abstract

The invention relates to a method for producing a sequence of high-voltage ignition sparks. According to said method, an ignition energy accumulator (2) is charged until it reaches a predetermined charge state (Ip, ZUND), an ignition spark is produced by discharging said ignition energy accumulator (2) on an ignition spark producing means (6) which is connected to the ignition energy accumulator (2), a process of recharging the ignition energy accumulator (2) is started before the ignition energy accumulator is fully discharged, and another ignition spark is produced on the ignition spark producing means (6) by discharging the ignition energy accumulator (2).

Description

Method for generating a sequence of high-voltage ignition sparks and high-voltage ignition device

The invention relates to a method for generating a sequence of high-voltage ignition pulses and a high-voltage ignition device according to the preamble of claim 8.

State of the art

Various high-voltage ignition devices are known in the prior art. In addition to the inductive ignition. capacitive ignition systems and alternating current ignition systems are also known. Furthermore, ignition systems have become known in the prior art, in which a sequence of high-voltage ignition sparks is generated. The device, also known as double ignition, generates a plurality of ignition sparks in a cylinder during a combustion process in order to improve the combustion. For this purpose, ignition systems are known, for example, which have a plurality of ignition energy stores, for example ignition coils. The ignition spark sequence is time-controlled in the prior art, this time control being carried out by software and / or hardware by means of a control unit. A disadvantage of the known multiple spark systems is that the time between an opening and Discharge of the ignition storage is relatively long. In addition, in the case of ignition systems with a plurality of ignition energy stores, an increased material expenditure is required.

Advantages of the invention

With the method for generating a sequence of high-voltage ignition pulses, which has the features of claim 1, and with the high-voltage ignition device, which has the features of claim 8, it is advantageously possible to determine the time between a discharge and a charging process to shorten an ignition energy store. This makes it possible to provide several high-voltage ignition sparks during a combustion process. However, it is also possible, due to the increase in the number of ignition sparks, to reduce the capacity of the ignition energy store, for example one that is smaller than in the prior art

Ignition coil to use. The reduction in the recharging time of the ignition energy store is essentially achieved by recharging it before it is completely discharged. Irrespective of parameter changes, such as the ignition voltage, the ignition voltage of the ignition spark, the speed of the internal combustion engine, the ratio of the air-fuel mixture, the battery voltage situation or the like, a residual ignition energy remains in the ignition energy store, so that the recharging process is shortened , whereupon the subsequent spark can be generated with a much shorter time interval to the first spark. In order to be able to prevent a complete discharge of the ignition energy store in a simple manner, in a further development of the invention it is provided that - while the ignition spark is burning - the 5 ignition spark current is measured and if the value of the ignition spark current falls below a definable value, the recharge process of the ignition energy store is started. In order to rule out uncontrolled re-ignition on the ignition spark generating means, the

10 can be caused, for example, by current peaks of the ignition spark current, it is provided in a particularly preferred embodiment that the recharging process of the ignition energy store is only started when the ignition spark current reaches the

15. has fallen below the definable value for a predetermined period. However, this also ensures a minimum spark duration, which is required for the ignition of the air-fuel mixture in the combustion chamber. Since switching on again

20 when falling below. spark current below the definable value, but the short recharge time of the spark memory is achieved because there is residual ignition energy in the memory.

25 If there is a measuring line from the ignition energy store to a control unit for an ion current measurement, this measuring line can be used to measure the ignition spark current. This results in an inexpensive and robust solution to the

30 Control of the recharge process by the control unit.

Further advantageous embodiments result from the subclaims. drawing

The invention is explained in more detail below on the basis of exemplary embodiments with reference to the drawing. Show it:

FIG. 1 shows a first exemplary embodiment of a high-voltage ignition device,

2 shows plotted against time the charging current of an ignition energy of Hochspannungszündvorrichtung, the spark current as well as a ^'control voltage,

FIG. 3 shows a second embodiment of a high-voltage ignition device, and

4 shows the current and voltage profiles associated with the high-voltage ignition device according to FIG. 3 over time.

Description of the ^' embodiments

Figure 1 shows a high-voltage ignition device 1, which includes an ignition energy storage 2, a control unit 3 and a switching element 4 u. The high-voltage ignition device 1 provides electrical energy for generating a high-voltage ignition spark at a spark gap 5. The spark gap 5 is formed on a spark generating means 6, which is preferably implemented as a spark plug. can be. The Zundenergiespeicher 2 is formed in 'preferred exemplary form as an inductor, so realized as an ignition coil ¹ 7, which has a primary winding 8 and a .Sekundärwicklung. 9 The spark generator 6 is connected to the secondary winding 9, an interference suppressor 10 and a so-called EFU diode 11 (switch-on spark suppression), the anode of which, and the spark gap 5, are arranged in this circuit

1.0 cathode are connected to the secondary winding 9. Furthermore, in this circuit there are still the erosion. The resistance 12 of the spark generating means and the resistance 13 of the ignition energy store 2 are shown. With its one winding end, the

15 secondary winding 9 thus connected to the spark gap 5 and with its other winding end to the control unit 3.

The primary winding 8 has one end of the winding at a supply voltage U _B , which is, for example, the battery voltage of an on-board battery of a motor vehicle. ^'The other winding end of the primary winding 8 is ^"' can be laid across the switching element 4 to ground. Depending on 25 the switching element 4 is controlled by the control unit 3 via a trigger output 4 ', that is, the power supply circuit is opened or closed for the primary winding 8. with a closed switching element 4 of the ignition energy is 30 2 overall load. After the charging of the ignition energy is stored Zundenergiespeichers 2, the degraded via the radio link 5 by opening the Schalteϊements 4 and the ignition _energy. 2 discharged thereby. The control unit 3 has a voltage measurement input 14 which is connected to a voltage tap 15 which is located in the primary-side circuit between the primary coil 8 and the switching element 4 in order to be able to measure the so-called clamp voltage of the ignition energy store 2. Furthermore, the control device 3 has a current measurement input 16 which is connected to a current tap 17 of the switching element 4. The primary current I _{p is} measured via this current measurement input 16, at least during the charging process of the ignition energy store 2. In addition, the control unit 3 includes a determining device 19 which determines the state of charge of the energy store 2 at least during the generation of ignition sparks. For this purpose, in a preferred embodiment, the determination device has a current measurement input 20 which is connected to a winding end of the secondary winding 9, so that the spark current I _p can be measured during the ignition spark generation. In order to be able to carry this out simply and easily, a measuring resistor 21, also referred to as a shunt, is connected to the connecting line between the Strpm measuring unit 20 and the secondary winding 9 with its one connection, the other connection of the measuring resistor 21 being connected to ground 18. Finally, the control device 3 has a control input 22 to which a control voltage U _E can be applied, which can be output by a switching device.

Reference to the figures 1 and 2a to 2c, the operation of the high-voltage ignition apparatus 1 will hereinafter be ^'explained: When the control input 22 of the control voltage U _E is located in a time clear t ₀ to t _E (Figure 2c). The control unit 3 then controls the switching element 4 so that the supply circuit for the primary winding 8 is closed and the primary current I _{p increases} from the point in time t ₀ . The current I _p changes depending on the state of charge of the ignition energy store 2. When a predeterminable value ^ _{P is reached} . _ZÖND ^{at the} time t _x , the switching element 4 is opened again via the control unit 3, so that the subsequent discharge process of the ignition energy store 2 causes the spark current I _F (FIG. 2b) to increase at the time t _x , whereupon the ignition spark burns on the spark gap 5 , By progressive discharge of the ignition energy to the spark Ström 2 I _F decreases. When a predeterminable trigger value I _{ra of} the spark current I _{F is reached} , which is detected by the determination device 19, the switching element 4 is closed again via the control unit 3 and. a recharging process of the ignition energy store 2 started at time t ₂ . The

Charging is again carried out until reaching the specified value I f ^ur ^ _PIZÜND ^en Primärström at time t ₃ is opened whereupon the switching element 4 via the control unit 3 again, so that by discharging a _{FolgeZündfunken.} ignites the spark gap 5 at time t ₃ , which continues to burn until the ignition spark current l _{p has} dropped again to the trigger value I _TR at time t ₄ , whereupon the switching element 4 is closed again and the ignition energy storage device is charged again is until the value of the primary current I _p again reaches the value I _{P / IGNIT} ^at time - t _s . By opening the switching element 4 again, a discharge process of the Ignition memory 2, which in turn generates an ignition spark at the spark gap 5 at time t _s . However, the driving voltage U _E is at the time t _E is not more at the control input 22, so that the controller 3 ^■ the switching element 4 does not close again and the spark burns out completely. It is thus readily apparent that, depending on the control duration t ₀ to t _E, an initial spark can be generated at time t _x , at least one or more subsequent sparks can be generated in the period t ₂ to t ₄ and an A final spark is generated at time t _s that can burn out.

In order to prevent an uncontrolled charging or discharging of the ignition energy store between two ignition sparks, for example in the period t ₂ to t ₃ , the switching element 4 for a charging process of the ignition energy store 2 is only closed when the ignition spark current I _{F has} the trigger value I _ra for falls below a certain time period, for example 20 μs to 80 μs, so that current peaks are quasi filtered out and are not taken into account when activating the switching element 4. The trigger value I _ra is less than the maximum current I _{P, raax} and can be, for example, 0.3 to 0.7 times the maximum ignition current I _{F $ max} . This trigger value I _ra can therefore be varied, preferably as a function of at least one operating parameter of the internal combustion engine. For example, the speed and / or the

Serve load of the internal combustion engine. In particular, it is provided that a characteristic curve field is available - in which several characteristic curves are contained, so that depending on these operating characteristic curves the Internal combustion engine the trigger value I _TR can be selected. Changing the trigger value I _{TR also} changes the duration of a single spark, so the number of sparks for a spark sequence can be changed.

From Figure 1 shows yet that both the control unit 3 and ^'the measuring resistor 21 and the switching element 4, which is formed in particular as a power switch, as the unit 3' can be manufactured inexpensively on a semiconductor substrate so that only four ^'terminals 23 to 26 must be led out of a housing accommodating this substrate. Of course, the control device 3, the measuring resistor 21 and the switching element 4 can be designed as separate components, which, however, can also be arranged in a single housing which has the connections 23 to 26.

Figure 3 shows a second embodiment of a high-voltage ignition device 1, wherein the detecting means to the control device 19 in a formed 3 upstream switching unit ^'27, which comprises a switching device 28 which has its output connected to the control input 22 of the controller 3 and the control voltage U _E for the control unit - 3 provides. The control voltage U _E is provided in a pulse-like manner in accordance with FIG. 4a, specifically as a function of the spark current I _F. If this spark current I _{F reaches} the trigger value 1 ^ (FIG. 4c), a control voltage pulse U _E is again applied to the control input 22, so that the control unit 3 closes the switching element 4 until the primary current I _{p reaches} the ignition value I _{P (ZÖND} (FIG. 4b), whereupon the switching element 4 is opened again, so that a spark can again be provided at the ^" spark gap 5 by discharging the ignition energy store 2. Advantageous in this provision of the control voltage U _E is that only three connections 23, 24 and 25 have to be led out of the housing which accommodates the unit 3 ', which has the control device 3 and the switching element 4.

In this exemplary embodiment of the high-voltage ignition device 1 according to FIG. 3, the current measurement input 20 is tapped between a Zener diode 29 and the measuring resistor 21, the Zener diode 29 being switched in the forward direction for the spark current I _p . The connecting line between the secondary winding 9 and the Zener diode 29 is passed on to an ion current measuring device 30, with which the ion current in the combustion chamber can be measured during spark breaks, in order, for example, to be able to assess the knocking behavior of the internal combustion engine. Otherwise, the same or equivalent parts in FIGS. 3 and 4 as in FIGS. 1 and 2 are provided with the same reference numerals. In this respect, reference is made to their description.

With the high-voltage ignition device 1, a multiple charging and discharging of the ignition energy store 2 is realized, the charging time compared to known systems for recharging the ignition energy store 2 being significantly reduced in order to reduce the pause times between two ignition sparks, since residual energy always remains in the ignition energy store 2. Inexpensive ignition energy storage devices, in particular coils, whose primary energy is <100 mJ can thus be used. By changing the trigger value I _ra for the spark current and change of the tripping current I _{P, züιro} may also include an adjustment to the respective supply voltage level, in particular loading situation, the ^'on-board battery can be achieved. In addition, the duration of a spark sequence or the number of sparks during a spark sequence can be varied.

The adaptation of the discharge time of the ignition energy store can also be adapted to the conditions in the secondary circuit of the ignition energy store 2 and of the ignition spark generation means 6, so that tolerances of the resistors 12, 10 and 13 in the secondary circuit can also be compensated for.

Claims

claims

1. A method for generating a sequence ^'of Hochspannungszundfunken, wherein

an ignition energy store (2) is charged up to a definable charge state (I _{P / ZÜHD} ),

an ignition spark is generated by discharging the ignition energy store (2) on an ignition spark generating means (6) connected to the ignition energy store (2),

-a recharge process of the ignition energy store (2) is started before the ignition energy store (2) is completely discharged, and

- By discharging the ignition energy store (2) a further spark is generated on the ignition spark generating means (6).

2. The method according to claim i, characterized in that the ignition spark current (I _F ) is measured during the spark generation and if the value falls below a definable value (1 ^) of the ignition spark current (I _F ) the recharging process of the ignition energy store (2) is started ,

3. The method according to ^' claim 1 or 2, characterized in that the recharging process of the ignition energy store (2) is started, when the ■ Ignition spark current (I _F ) has fallen below the definable value (I _TR ) for a predefinable period.

4. The method according to any one of the preceding claims 5, characterized in that at least one charging process, one recharging process and one complete discharging process of the ignition energy store (2) take place within one combustion cycle.

5. The method according to any one of the preceding claims, characterized in that the number of recharging processes within a combustion cycle is determined as a function of operating parameters of the internal combustion engine.

15

6. The method according to any one of the preceding claims, characterized in that an ion current measurement is carried out during a spark break and that as a function of that from the ion current measurement

20 determined parameters, the start time of the recharging process of the ignition energy store (2.) is selected.

7. The method according to one of the preceding claims, characterized in that the trigger value

(I _TR ) for the spark current (I _F ) depending on at least one operating parameter, in particular the speed and / or load, of the internal combustion engine can be varied.

30th

8. High-voltage ignition device for generating a spark sequence, with an ignition energy store, a switching element for the ignition energy store, which an energy supply device with the ignition energiespe cher connects and interrupts, and a control device for controlling the switching element, characterized by a determining device (19) for the state of charge (Iτ _{? ιZäSD} ) of the ignition 5 energy _{storage device} (2), the control _device (3) controlling the switching element ( 4) then closes again when the state of charge of the ignition energy store (2) falls below a predeterminable value and the switching element (4) is opened again when a predeterminable state of charge is reached again.

9. High-voltage ignition device according to claim 8, characterized in that the determining device (19) is a current measuring device for the

15 spark current (I _F ) ^' .

10. High-voltage ignition device according to claim 8, characterized in that the ignition energy store (2) is an inductor.

20

That the control device (3) 11 High-voltage ignition apparatus according to one of ^claims' 8 and 9, characterized in that the determining means (19).

25

12. High-voltage ignition device according to claim 8, characterized in that the switching element (4) is a semiconductor switching element.

• 30 13. High-voltage ignition device according to one of claims 8 to 12, characterized in that the semiconductor switching element and the control device (3) are arranged on a common substrate.

14 .. High-voltage ignition device according to one of the preceding claims 8 to, 13, characterized by an ion current measuring device (30).