Title of Invention

A DEVICE AND A METHOD FOR REGULATING AN ENERGY SUPPLY FOR AN IGNITION OF AN INTERNAL COMBUSTION ENGINE

Abstract A device for regulating the energy supply for the ignition of an internal combustion engine including an ignition coil and a central control unit, the ignition coil including a primary winding and an ignition power module connected to the primary winding. The central control unit ascertains a time difference between the beginning of current flow through the primary winding and the reaching of a first threshold value of the primary current, and in the light of the time difference, the central control unit determines an additional power loss of the ignition power module and/or active energy reduction, caused by interturn short circuits in the primary winding. When the additional power loss of the ignition power module exceeds a power loss threshold value, the ignition power module is switched off.
Full Text The invention is based on a device and a method for regulating the energy supply for the ignition in an internal combustion engine of the generic type of the independent claims. A device and a method for regulating the" energy supply for the ignition in an internal combustion engine have already been disclosed in the publication "Technische Unterrichtung, Kombiniertes Ziind- und Benzineinspritzsystem mit Lambda-Regelung-Motronik" [Technical training, combined ignition and petrol ignition system with lambda-regulating motronic]", Robert Bosch GmbH, 1983. In said publication, a closing angle controller is described on page 11, the energy which is continuously increased over the closing time and reached at the ignition time and stored in the magnetic field of the ignition coil and is, in a first approximation, proportional to the square of the primary current value reached is changed as a function of a characteristic diagram. Here, the characteristic diagram is a function of the battery voltage and of the engine speed.
Furthermore, in the German Patent Application with the file number 199 563 81.0, a device and a method for igniting an internal combustion engine are described in which the switch-on time, i.e. the time difference between the switch-on edge in the signal line which corresponds to the start of the flow of current through the primary winding and the time at which the primary

current reaches a first threshold value, is determined. The switch-on time is determined by reference to the signals in the signal line and signals on one or more diagnostic lines which connect a central control unit to the ignition output stage.
Advantages of the invention
The device according to the invention or the method according to the invention having the features of the independent claims has, in contrast, the advantage that it is ensured that overheating of the ignition output stage does not occur, i.e. the [sic] a maximum acceptable power loss which drops in the ignition output stage 13 is not exceeded, and on the other hand a sufficient energy supply is present for the ignition. Here, the avoidance of the upward transgression of the maximum power loss has priority. It is thus possible to react directly on the changes in the primary winding, such as newly arising short circuits, i.e. coil defects and cable harness defects, arising during the running time of the engine. In this context, the regulating operation can be carried out in both directions, i.e. in the direction of an increase or of a decrease in the energy supply.
The measures specified in the subclaims make possible advantageous developments and improvements of the device and method specified in the independent claims. It is particularly advantageous that the ignition output stage temperature can be determined by reference to the power loss dropping in the ignition output stage, using the temperature of the surroundings of the ignition output stage, in which case, in order to avoid damage, the ignition output stage has to be switched off if the temperature of the ignition output stage is too high. It is advantageous here to determine the temperature of the surroundings of the ignition output

stage by means of a temperature sensor as the ambient temperature can be specified very precisely in this way. It is also advantageous to read out the ambient temperature of the ignition output stage from a characteristic diagram from a storage unit of the central control unit by reference to a predefined value or as a function of specific operating states as in this way there is no need for a temperature sensor. It is also advantageous, when a temperature sensor is present, to use the characteristic diagram dependence of the ambient temperature of the ignition output stage to check the operational capability of the temperature sensor and, in the event of a fault, replace the ambient temperature determination of the sensor with the characteristic diagram. Furthermore, it is advantageous to calculate the power loss consumed by line and interturn resistors which are temperature-dependent, by reference to the determined temperature of the primary winding, and to take this power loss into account in the provision of the energy supply. Further advantageous developments and improvements can be taken from the description of the exemplary embodiments below.
Drawings
Exemplary embodiments of the invention are represented in drawings and described in more detail in the following description, in which:
Figure 1 shows a device according to the invention for
regulating the energy supply in the primary winding of
an internal combustion engine ignition coil.
Figure 2 shows a schematic equivalent circuit diagram
for the primary winding of an ignition coil together
with a connection to the battery voltage and a
controllable switch.
Figure 3 shows a further exemplary embodiment for a

device according to the invention for regulating the energy supply in the primary winding of an internal combustion engine ignition coil, and
Figure 4 shows a diagram in which the primary current is plotted as a function of time.
Description of the exemplary embodiments
Figure 1 is a schematic illustration of a device for regulating the energy supply in the primary winding of an internal combustion engine ignition coil. Here, the ignition circuit 2 contains an ignition coil with a secondary winding 4 and a secondary winding 7 for each cylinder of the internal combustion engine, one end of the secondary winding 7 being connected to ground and the other end of the secondary winding 7 being connected to an electrode of the spark plug 10. The other electrode of the spark plug 10 is connected to ground. One end of the primary winding 4 is connected to a battery voltage (Ubat) 9- The other end of the primary winding 4 is connected to a controllable switch 12, the controllable switch 12 being part of an ignition output stage 13. In one preferred exemplary embodiment, the controllable switch 12 is embodied as a power transistor, the primary winding 4 being then connected to the collector of the power transistor. The other output of the controllable switch is connected to ground, and when a power transistor is used as the controllable switch 12 the emitter of the power transistor is preferably connected to ground. The control input of the controllable switch 12, preferably the base of the power transistor, leads to a central control unit 16 via a signal line 14. The central control unit 16 includes an arithmetic unit 161, a storage unit 162, a regulating unit 163 and a switch-off unit 164, the switch-off unit 164 being connected to the ignition output stage 13 via a connecting line 19. The ignition output stage 13 is also connected to

the central control unit 16 via a diagnostic line 15.
If an ignition is to take place, a signal edge is firstly transmitted from the central control unit 16 via the signal line 14 to the ignition output stage 13, i.e. to the controllable input of the controllable switch 12, and when the controllable switch 12 is embodied as a power transistor, preferably to the base of the power transistor. This edge causes the controllable switch 12 to connect through and brings about a flow of current through the primary winding 4. The current flows here from the connection to the battery voltage 9 via the primary winding 4, the controllable switch 12 to ground. At the ignition time, a second edge is transmitted to the controllable switch 12 by the central control unit 16 via the signal line 14, the controllable switch then blocking. As a result, the flow of current in the primary winding 4 is interrupted and a voltage is induced in the secondary winding 7, which voltage leads to the generation of an ignition spark in the spark plug 10.
As has already been described in the patent application with the file number DE 199 56 381.0, the ignition output stage 13 contains signal-forming elements, preferably edge-forming elements, and comparators and/or sensors, which can compare variables of the ignition current circuits, preferably primary current and primary voltage, with threshold values. The ignition output stage 13 preferably contains a comparator which compares the primary current, i.e. the current through the primary winding 4 of the ignition coil, with a first threshold value II, and, at the time at which the primary current exceeds the first threshold value II, transmits, by means of the edge-forming element which is also present in the ignition output stage 13, an edge onto the diagnostic line 15 which passes to the central control unit 16 via the

diagnostic line 15. The central control unit 16 also contains a time-processing unit which compares signals on the signal line and signals on the diagnostic line with a time counting unit, and can thus determine time intervals.
The profile of the primary current will now be explained once more with reference to the diagram illustrated in Figure 4, in which the primary current is plotted as a function of time. At a time Tl, the controllable switch 12 is closed by an edge on the signal line, and a flow current is thus switched on through the primary winding 4 of the ignition coil. This current rises, as represented, with time and exceeds a first threshold value II at a time T3. The comparator which is present in the ignition output stage 13 compares the primary current with this first threshold value II. As already explained, a signal is sent via the diagnostic line 15 to the central control unit 16 by the signal-forming element contained in the ignition output stage 13 when this first threshold value II is exceeded, and an edge is preferably sent by an edge-forming element of the ignition output stage 13 to the central control unit 16 via the diagnostic line 15.
The central control unit 16 then performs, with a time-processing unit, a comparison of the signals on the signal line 14 and on the diagnostic line 15 with a time counting unit, in particular the time period is determined between the edge on the signal line 14, which brings about through connection of the controllable switch 12, and the edge which passes to the central control unit on the diagnostic line 15 as a result of a first threshold value of the primary current on the diagnostic line 15 being exceeded. This time is referred to below as a switch-on time and corresponds to the time t3 - tl in Figure 4.

For an internal combustion engine having a plurality of cylinders, an ignition circuit 2 is provided for each cylinder, each ignition circuit being connected to the central control unit using a signal line. For each ignition output stage 13 of each cylinder there is a diagnostic line 15 which starts from the respective ignition output stage 13. The diagnostic line 15 which starts from the ignition output stage 13 of each cylinder can either be connected directly to the central control unit 16 or, in one preferred exemplary embodiment, can be conducted via a logic element (not illustrated) in which the diagnostic lines of a plurality of cylinders are connected to form one diagnostic line, the logic element then being in turn connected to the central control unit 16 via a logic linking diagnostic line. In the logic element, the incoming diagnostic signals from each cylinder are linked in a chronologically correct sequence. The linking is described in detail in the patent application with the file number DE 199 56 381.0.
Figure 2 is an equivalent circuit diagram of the primary winding 4 of the ignition coil. The terminals 9 to the battery voltage Ubat and the controllable switch 12 as well as the linking between the controllable switch 12 and the primary ending 4 are also illustrated. The resistors and the inductors which are present in the primary winding 4 can be represented by a leakage inductance 47 connected in series from the battery voltage to the controllable switch 12, a line and interturn resistance 45 and an effective inductance 41. In parallel with the effective inductance there is in turn a short circuit resistance 43 which represents the ohmic resistances which can vary over the operating time of the primary winding. The leakage inductance 47 and the line and interturn resistance 45 are known from the data of the primary coil. The primary current Ip 48 flows through the leakage inductance 47 and through the

line and interturn resistance 45. This primary current is divided by the effective inductor 41 and the short circuit resistor connected in parallel thereto into an effective current Ih which flows through the effective inductor 41, and a short circuit current which flows through the short circuit resistor 43. The sum of the two currents generates a power loss in the ignition output stage 13. What is referred to as the effective energy, i.e. the energy which is actually available to the spark plug 10 for the ignition flame, is also generated in the effective inductor 41. The latter is determined by the current flowing through the inductor, at the time at which the controllable switch switches off. Here, as already described above, the current flowing through the inductor rises continuously over the closing time.
In the normal state, i.e. without the presence of interturn resistances in the primary coil, the short circuit resistor 43 is very large, i.e. only a very small negligible current flows across the short circuit resistor 43. However, if there are interturn short circuits when there is a fault, the value of the short circuit resistor 43 drops and a large current flows across the short circuit resistor 43 especially just after the controllable switch 12 connects through at the start of the closing time. If the overall current, i.e. the sum of the currents via the effective inductor 41 and via the short circuit resistor 43, is considered in the case of a fault, this overall current is significantly increased in comparison to the normal state, especially just after the controllable switch 12 connects through. This leads to an increased power input into the ignition output stage 13 in comparison to the normal state, and thus to an increase in the temperature of the ignition output stage 13. In the worst case, an upward transgression of a maximum temperature can lead to the ignition output stage 13

being destroyed. Furthermore, the energy which is lost in the short circuit resistor and in the ignition output stage 13 leads, when there is constant closing time, to a reduction in the effective energy in comparison with the normal state, i.e. the energy which is available for the ignition is reduced, which can lead to misfires.
By reference to the switch-on time which, as explained above, was determined in the central control unit 16 and is available there, it is then possible to determine the power loss [lacuna] ignition output stage 13 which is due to short circuits in the primary coil windings. The reduction in the effective energy can also be determined. This can preferably be carried out in that a short circuit resistance value Rshort is assigned to the determined switch-on time by means of a characteristic diagram which also depends on the battery voltage Ubat • This characteristic diagram is contained in the storage unit 162. Here, the value which is measured at the respective time is used as the battery voltage Ubat- By reference to this short circuit resistance value Rshort/ the power loss dropping additionally in the ignition output stage 13 and the effective energy reduction occurring in the effective inductor 41 are then also determined by means of a battery-voltage-dependent characteristic diagram. This characteristic diagrams [sic] are also contained in the storage unit 162.
After the power loss which drops additionally in the ignition output stage 13 and the effective energy reduction are determined, it is initially checked to determine whether the power loss dropping additionally in the ignition output stage 13 exceeds a power loss threshold value. If this is the case, the ignition output stage 13 of the respective cylinder is switched off, this is because there is then the risk of the

ignition output stage 13 being destroyed. Alternatively, the closing time can also be reduced as in this way the power loss in the ignition output stage 13 is reduced. Here, the time between the start of the flow of current through the primary winding, i.e. the connecting through of the controllable switch 12 and the switching off of the flow of current through the primary winding, i.e. switching off of the controllable switch 12, is referred to as closing time tciose-Accordingly, the time distance between the edge which connects through the controllable switch 12 and the edge which switches the controllable switch 12 off again is preferably reduced in order to shorten the closing time.
In a further exemplary embodiment, switching off of the ignition output stage 13 or reduction in the closing time can also be provided with a time constant, which means that after the upward transgression of the power loss threshold value is first detected and when this state persists over a plurality of cycles, the subsequent handling (switching off or reduction of the closing time) is performed only after a specific time as this state leads to the ignition output stage 13 being destroyed only if it persists for a relatively long time. It is advantageous here to avoid ignition output stage switch-off operations or closing time reduction operations which are based on faulty power loss values or effective energy values.
If the power loss threshold value is not exceeded, the closing time is then prolonged in accordance with the effective energy reduction so that the current which is increased by the effective inductor 41 at the time when the controllable switch 12 is switched off [lacuna] owing to a relatively long closing time. In this way, the effective energy is increased, i.e. a relatively large amount of energy is made available to the

ignition and the effective energy reduction is minimized. The closing time is regulated by the regulating unit 163. As the additional power loss which occurs in the ignition output stage 13 is also increased owing to a prolonged closing time, it is necessary at each increase in the closing time to check whether the power loss threshold value is exceeded.
In a further exemplary embodiment, a reduction in the closing time is provided if a smaller reduction is determined in the effective energy than at an earlier time. This reduction in the closing time is carried out by means of the regulating unit 163. The effective energy should however not drop below an effective energy threshold value as misfires may occur if the energy available for the ignition is too small. This causes worsening of the smooth running of the internal combustion engine.
In other exemplary embodiments, instead of regulating the closing time tciose/ the voltage made available to the primary winding is regulated by the regulating unit 163.
In a preferred exemplary embodiment, the closing time or the voltage which is made available to the primary winding is changed in the respective desired direction by the regulating unit 163 in small increments.
A power loss temperature, which is generated by the fact that ohmic heat is released in the ignition output stage 13, can also be assigned to a specific additional power loss occurring in the ignition output stage 13 by the central control unit 16. This power loss temperature can be estimated and is contained in the storage unit 162 as a characteristic curve as a function of the short circuit resistance value Rshort or as a function of the additional power loss in the

ignition output stage. Furthermore, the surroundings of the ignition circuit 2 have a specific ambient temperature which depends, for example, on the weather conditions, the duration of operation of the internal combustion engine in the respective operating cycle and on other thermally coupled ohmic resistors located in the vicinity of the ignition circuit 2, and a cooling means which may possibly be present. The ambient temperature can be estimated by a permanently predefined value in a rough approximation, or be present in a characteristic diagram in the storage unit 162 of the central control unit 16 as a function of specific operating states which is [sic] characterized, for example, by the duration of operation after the switching on of the internal combustion engine or on the temperature of the cooling water at the cylinder head. However, the ambient temperature can also be measured in one preferred embodiment by means of a temperature sensor 20 (as illustrated in Figure 3) in the vicinity of the ignition circuit 2. The temperature sensor is connected to the central control unit 16 via the sensor line 18.
With the exception of the temperature sensor 2 0 and the sensor line 18, the device illustrated in Figure 3 for regulating the energy supply in the primary winding corresponds to an internal combustion engine ignition coil of the device illustrated in Figure 1. For this reason, details will not be given again of the other components of the device illustrated in Figure 3.
In one preferred exemplary embodiment, the [lacuna] of the temperature sensor (20) is checked by means of the central control unit (16) to determine whether the temperature sensor supplies plausible values for the ambient temperature. This can be done, preferably, by the temperature determined by the temperature sensor (20) lying in a plausible temperature range. Should the

values determined by the temperature sensor for the ambient temperature not lie in the plausible temperature range, it is assumed that the temperature sensor (20) or the sensor line (18) has a defect. The values which are used to determine the temperature of the ignition output stage for the ambient temperature are then read from a characteristic diagram or a permanently predefined value is used. The characteristic diagram is present here in the storage unit 162 of the central control unit 16, as a function of specific operating states which are characterized, for example, by the duration of the operation after the switching on of the internal combustion engine or by the temperature of the cooling water at the cylinder head.
The temperature at the ignition output stage 13 can then be determined by reference to the power loss temperature and the ambient temperature. It is obtained as a sum of the power loss temperature and ambient temperature. It is determined by the arithmetic unit 161 of the central control unit. The central control unit 16 then makes a comparison between the temperature of the ignition output stage 13 and a temperature threshold value. If the temperature of the primary winding is higher than the temperature threshold value, the ignition circuit is overheated and it is necessary to switch off the ignition output stage 13 . This is performed by the switch-off unit 164 which is connected to the ignition output stage 13 via a connecting line 19, the central control unit 16 bringing about the switching off of the ignition output stage 13 via the switch-off unit 164.
Here too, it is possible, in one preferred exemplary embodiment, to provide, in a way analogous to the switching off of the ignition output stage 13, on the basis of the upward transgression of the power loss

threshold value, a temperature time-constant which are [sic] then displaced the switching off of the ignition output stage 13 [sic] by a specific defined time after the first detection of the upward transgression of the temperature threshold value.
When there is an increase in temperature of the ignition output stage 13, there is still an increase in the line and interturn resistances 45 of the primary coil. This leads to more power loss being conducted away via the line and interturn resistances 45 than in the cold state. For this purpose it is necessary to prolong the closing time in proportion to the temperature of the primary winding 4. This can preferably be carried out in that a characteristic curve which makes available a closing time prolongation value tpr-oiong as a function of the temperature of the primary winding is present in the storage unit 162. This closing time prolongation value tproiong is added to the closing time tciose which is obtained from the regulation of the closing time as described above, with reference to the additional power loss of the ignition output stage and with reference to the effective energy.
When there is a constant closing time, it is possible, in a further exemplary embodiment, to observe a symmetrical, strongly continuous prolongation of the switch-on time and to estimate a thermally conditioned increase in the ohmic resistance of the primary winding of the coil by reference to said switch-on time.
In a further exemplary embodiment, increased line and interturn resistances due to increased temperature can be compensated by increasing the voltage present at the primary winding.
In a further preferred exemplary embodiment, it is

possible also to transfer the devices and methods described above to an internal combustion engine having a plurality of cylinders. In an internal combustion engine having a plurality of cylinders, each cylinder is assigned an ignition circuit 2 which is connected via one signal line 14 each to the central control unit 16. A diagnostic line 15, via which the ignition output stage 13 is connected to the central control unit and via which the diagnostic signals can be transmitted, leads from the ignition output stage 13 of each cylinder. Preferable logic linking of a plurality of diagnostic lines to form one logic linking diagnostic line has already been described above. For an internal combustion engine having a plurality of cylinders, the additional power loss of the ignition output stage 13 or the effective energy reduction of each cylinder is preferably performed on a cylinder-specific basis, and the closing time regulation is thus also performed on a cylinder-specific basis. In this way, the temperature of the ignition output stage 13 is preferably also determined on a cylinder-specific basis, resulting in cylinder-specific switching off of the respective ignition output stage 13 when the power loss threshold value or the temperature threshold value is exceeded. The closing time prolongation value tproiong/ which is obtained from the temperature-conditioned increase in the line and interturn resistance, is preferably also determined on a cylinder-specific basis and added to the closing time tciose-
In a further preferred exemplary embodiment, the time-processing unit, which performs the determination of the switch-on time from the signals of the signal line 14 or the signal lines 14 and the signals of the diagnostic line 15 or the diagnostic lines 15 or the logic linking diagnostic line or the logic linking diagnostic lines, can also be arranged separately from the central control unit 16.

In a further preferred exemplary embodiment, the average power loss in the ignition output stage is dependent on other operating parameters, preferably on the rotational speed. The additional power loss of the ignition output stage is thus also dependent on other operating parameters (in addition to the battery voltage dependence), preferably on the rotational speed. This operating parameter dependence is ensured by a characteristic diagram which is contained in the storage unit 162.
In a further preferred exemplary embodiment, the power loss temperature which is present in a characteristic diagram in the storage unit 162 is dependent on the short circuit resistance value Rshort and further parameters, preferably dependent on the ambient temperature or on the time which has passed since the internal combustion engine started, or contained [sic] by the temperature of the cylinder head cooling water.


WE CLAIM :
1. A device for regulating an energy supply for an ignition of an internal combustion
engine, the device comprising:
an ignition coil having a primary winding (4) and an ignition output stage (13) connected to the primary winding (14); and
a central control unit (16) to ascertain a time difference between a beginning of a current flow through the primary winding (4) and a reaching of a first threshold value of a primary current, characterized in that the central control unit (16) determines a power loss of the ignition output stage (13) as a function of the time difference, the central control unit (16) compares power loss to a power loss threshold value, and the energy supply for the ignition being reduced by the central control unit (16) when the power loss of the ignition output stage (13) exceeds the power loss threshold value.
2. The device as claimed in claim 1, wherein the central control unit (16) detects that the
power loss threshold value has exceeded by the power loss of the ignition output stage (13),
the ignition output stage (13) is switched off by switch-off unit (164) connected to the
ignition output stage (13).
3. The device as claimed in claim 1, wherein the central control unit (16) comprises a
regulating unit (163), the energy supply for the ignition being regulated by the regulating unit
(163) such that a reduction of the energy supply for the ignition is a minimum.
4. The device as claimed in claim 3, wherein the regulating unit (163) comprises a
regulating variable of the energy supply for the ignition which represents a closing time.
5. The device as claimed in claim 4, wherein the ignition output stage (13) is switched off
by the switch-off unit (164) only after a certain fixed, predefined time after it has been
determined by the central control unit (16) that one of the power loss threshold value and the
temperature threshold value has been exceeded.
6. The device as claimed in claim 3, wherein the regulating unit (163) comprises a
regulating variable of the energy supply for the ignition which represents a voltage.

7. The device as claimed in claim 3, wherein the regulating unit (163) performs regulation
of the energy supply for the ignition in a plurality of steps and after each regulating step, an
exceeding of the power loss threshold value by the power loss of the ignition output stage
(13) is checked, by the central control unit (16).
8. The device as claimed in claim 7, wherein after each regulating step by the regulating unit (163), which is connected with a decrease in the energy supply for the ignition, a fall below the power loss is checked using the central control unit (16).
9. The device as claimed in claim 8, wherein the central control unit (16) comprises a switch-off unit (164) connected to the ignition output stage (13), such that when a temperature of the ignition output stage (13) exceeds a temperature threshold value, the ignition output stage (13) is switched off

10. The device as claimed in claim 3, wherein the ignition output stage (13) is switched off by the switch off unit (164) only after a certain fixed, predefined time after it has been determined by the regulating unit (163) that one of the power loss of threshold value and a temperature threshold value has been exceeded.
11. The device as claimed in claim I, wherein the central control unit (16) ascertains a power loss temperature corresponding to the power loss of the ignition output stage (13), such that a temperature of the ignition output stage (13) is ascertained as a sum of the power loss temperature and an ambient temperature.
12. The device as claimed in claim 11, wherein the central control unit (16) is connected to
a temperature sensor (20), such that the ambient temperature is ascertained.
13. The device as claimed in claim 12, wherein the ambient temperature is available as one
of a fixed, predefined value and a function of operating states in a characteristics diagram in a
storage unit (162) of the central control unit (16).

14. A method for regulating an energy supply for an ignition of an internal combustion
engine comprising an ignition coil and a central control unit (16), the ignition coil having a
primary winding (4) which is connected to an ignition output stage (13), the method
comprising the steps of:
determining a time difference between a beginning of a current flow through the primary winding (4) and a reaching of a first threshold value of a primary current by the central control unit (16);
determining a power loss of the ignition output stage (13) caused by a plurality of intertum short circuits in the primary winding (4), as a function of the time difference using the central control unit (16);
comparing the power loss with a power loss threshold value; and
reducing the energy supply for the ignition when the power loss of the ignition output stage (13) exceeds the power loss threshold value.
15. The method as claimed in claim 14, wherein said method comprises the step of:
switching off the ignition output stage (13) by a switch off unit (164) connected to the
ignition output stage (13), at a time when an exceeding of the power loss threshold value by
the power loss of the ignition output stage (13) is determined by the central control unit (16).
16. The method as claimed in claim 15, wherein a power loss temperature is ascertained from the power loss of the ignition output stage (13), and from the power loss temperature, a temperature of the ignition output stage (13) is ascertained, the temperature of the ignition output stage (13) being derived as a sum of the power loss temperature and an ambient surroundings temperature.
17. The method as claimed in claim 16, wherein the ignition output stage (13) is switched off by a switch off unit (164) at a time when a temperature of the ignition output stage (13) exceeds a certain, predefinable temperature threshold value.

18. The method as claimed in claim 17, wherein the ignition output stage (13) is switched off by the switch off unit (164) only after a certain fixed, predefined time after it has been determined that one of the power loss threshold value and the certain, predefinable temperature threshold value has been exceeded.
19. The method as claimed in claim 16, wherein, when the temperature sensor is defective, the ambient temperature is one of derived from a fixed, predefined value and read out from a characteristics diagram as a function of a plurality of operating states of the internal combustion engine.

20. The method as claimed in claim 15, wherein the ignition output stage (13) is switched off by the switch off unit (164) only after a certain fixed, predefined time after it has been determined that one of the power loss threshold value and a certain, predefinable temperature threshold value has been exceeded.
21. The method as claimed in claim 14, wherein the energy supply for the ignition is regulated by a regulating unit (163) of the central control unit (16), such that a reduction of the energy supply for the ignition is a minimized.
22. The method as claimed in claim 21, wherein a controlled variable of the energy supply for the ignition represents a closing time.
23. The method as claimed in claim 21, wherein a controlled variable of the energy supply for the ignition represents a voltage.
24. The method as claimed in claim 21, wherein regulation of the energy supply for the ignition is performed in a plurality of steps by the regulating unit (163), and after each regulating step, an exceeding of a power loss threshold value by the power loss of the ignition output stage (13) is checked using the central control unit (16).
25. The method as claimed in claim 24, wherein after each regulating step in which the
energy supply for the ignition is reduced, a fall below the power loss is checked by the central
control unit (16).

26. The method as claimed in claim 25, wherein the ambient temperature is one of derived
from one of a fixed, predefined value and a characteristics diagram as a function of a plurality
of operating states of the internal combustion engine and ascertained with aid of a
temperature sensor.
27. The method as claimed in claim 25, wherein an additional ohmic power loss of line and
intertum resistors (45) conditioned upon an increased temperature is ascertained by the
central control unit (16) in light of a temperature of the ignition output stage (13), and is
considered by a prolonging of the closing time.

Documents:

in-pct-2002-1430-che abstract duplicate.pdf

in-pct-2002-1430-che abstract.jpg

in-pct-2002-1430-che abstract.pdf

in-pct-2002-1430-che claims duplicate.pdf

in-pct-2002-1430-che claims.pdf

in-pct-2002-1430-che correspondence others.pdf

in-pct-2002-1430-che correspondence po.pdf

in-pct-2002-1430-che description (complete) duplicate.pdf

in-pct-2002-1430-che description (complete).pdf

in-pct-2002-1430-che drawings duplicate.pdf

in-pct-2002-1430-che drawings.pdf

in-pct-2002-1430-che form-1.pdf

in-pct-2002-1430-che form-18.pdf

in-pct-2002-1430-che form-26.pdf

in-pct-2002-1430-che form-3.pdf

in-pct-2002-1430-che form-5.pdf

in-pct-2002-1430-che others.pdf

in-pct-2002-1430-che pct.pdf

in-pct-2002-1430-che petition.pdf


Patent Number 206917
Indian Patent Application Number IN/PCT/2002/1430/CHE
PG Journal Number 26/2007
Publication Date 29-Jun-2007
Grant Date 16-May-2007
Date of Filing 11-Sep-2002
Name of Patentee M/S. ROBERT BOSCH GMBH
Applicant Address Postfach 30 02 20 70442 Stuttgart
Inventors:
# Inventor's Name Inventor's Address
1 GERHARDT, Juergen Gerd-Gaiser-Strasse 23 71739 Oberriexingen
2 HAUSSMANN, Martin Kirchhofstrasse 3 74343 Sachsenheim
PCT International Classification Number F 02 P 3/05
PCT International Application Number PCT/DE2001/000689
PCT International Filing date 2001-02-23
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 100 12 956.0 2000-03-16 Germany