EP1141542B1 - Ignition system and ignition control method - Google Patents

Description

STATE OF THE ART

The invention relates to an ignition system and a method for ignition control for an internal combustion engine, which has a plurality of cylinders, wherein a separate Zündungsaussetzzähler is provided for each cylinder.

There are known ignition systems for internal combustion engines with a plurality of combustion cylinders, which have a corresponding ignition misfire counter in a control unit for each cylinder. The combustion cylinders of the internal combustion engine are ignited by ignition coils, which have a primary and secondary winding, by inductive generation of a high voltage. The currents occurring in the secondary circuit are detected by a Zündungsstromsensor and cylinder selectively fed to a Zündausauswerteeinrichtung. If the ignition current sensor detects an ignition misfire in one of the monitored cylinders, it sends a corresponding exposure count signal to the evaluation device. This increments an internal sparkout counter provided to the cylinder by a predetermined increment value, which is an adjustable constant counter slope, for example 2. If no ignition misfire is detected for the associated cylinder, the corresponding ignition misfire counter will be detected by an adjustable constant decrement value, for example, by 1, decrements.

In the practical application of the ignition current evaluation, it has been found that the dimensioning of the detection circuit has a great influence. If the detection circuit is designed to respond early to an ignition misfire, there is a danger that ignitions in the cylinder that have been made in the desired manner will be erroneously recognized as ignition misfires. In an interpretation of the detection circuit, in which even weaker current signals in the secondary circuit of the ignition system still generate a trigger signal in the detection circuit, conversely, really occurring ignition misfires, which are caused for example by a sooty spark plug, not recognized. A certain number of false triggering occurrences, which occur when successful ignitions are recognized as faulty, can be filtered out by taking measures only when the ignition misfire counter of the relevant cylinder has reached a predetermined adjustable counter threshold value.

However, the counter threshold must not be too high or the counter slope with which the counter is increased when misfiring is detected must not be too low, so that a sufficiently fast response is ensured with several sequential ignition misfires, in particular for the protection of the catalyst. Because the ignition misfire counter In such conventional ignition systems has a constant counter slope, in the determination of the counter threshold a compromise must be found between a rapid response for the catalyst protection, if several cylinders fail simultaneously, and a statistical filtering in the evaluation of possibly erroneously detected, individual ignition misfires on the cylinder , Thus, on the one hand, the counter threshold must be high enough not to be exceeded by erroneous single spark misfires, and on the other hand low enough to ensure a fast response.

Such conventional ignition systems have the disadvantage that they do not take into account how many ignition misfires have occurred in the various cylinders of the internal combustion engine, for example in a cylinder bank. If ignition misfires occur simultaneously with several cylinders during one revolution, the reaction of the ignition system must be particularly fast. In the known ignition system, the individual Zündungsaussetzzähler the cylinder is increased independently of the Zündungsaussetzzähler other cylinders. This can lead to the fact that the reaction of the ignition system is too slow at the same time occurrence of misfires in multiple cylinders.

From US-A-5,334,938, US-A-5,359,822 and US-A-5,343,844 each ignition systems for an internal combustion engine are already known, which have a detection device for detecting occurring in the cylinders misfires. Furthermore, in each case a calculation device is provided which has an associated ignition exposure counter for each cylinder. At detected ignition misfires, the ignition exposure counters associated with each of the cylinders are increased.

The ignition system according to the invention with the features of claim 1 and the corresponding Zündsteuerverfahren with the Features of claim 8 have the advantage that in the evaluation of the ignition exposure behavior of a cylinder detected in the other cylinders ignition misfire are taken into account and a rapid response of the ignition system is ensured with simultaneous occurrence of ignition misfires in different cylinders.

The ignition system according to the invention has a detection device for detecting the ignition misfire occurring in each cylinder and a calculation device which has at least one ignition misfire counter for each individual cylinder, wherein the ignition misfire counter at an ignition misfire detected in the associated cylinder during a motor rotation depending on the total number of ignition misfires the previous engine revolution detected ignition misfire of all cylinders is increased.

The idea underlying the present invention is that the Zündaussetzzähler a cylinder is no longer increased as before with a constant increment value at detected misfire, but with a variable increment value, which is higher, the more cylinders had a misfire in the previous engine revolution ,

In the dependent claims are advantageous developments and improvements specified in claim 1 Ignition system and specified in claim 8 Zündsteuerverfahrens.

According to a preferred refinement, when an adjustable counter threshold value is exceeded by an ignition misfire counter for this cylinder, the calculation device emits an emergency measure control signal to an emergency measure control device for initiating an emergency measure.

According to a further preferred development, the emergency measure procedure is that the injection of the corresponding cylinder is switched off.

According to a further preferred development, the ignition blanking pattern is increased by a variable increment value in an ignition misfire detected in one revolution, which is calculated by multiplying the total number of ignition misfires detected in the previous revolution by a constant adjustable initial increment factor in all cylinders.

According to a further preferred refinement, the calculation device decrements the ignition exposure counter of a cylinder if the detection device for this cylinder does not detect an ignition misfire.

According to a further preferred embodiment, the ignition blanking counter becomes a constant adjustable value decrements when no misfire is detected by the detector for that cylinder.

According to a further preferred refinement, a plurality of different ignition blanking counters for different emergency measures are provided for each cylinder, each having separately adjustable initial increment factors and counter threshold values.

This offers the particular advantage that, depending on the values of the various ignition misfires, different measures can be carried out at different threshold values.

DRAWING

An embodiment of the ignition system according to the invention is explained in more detail in the drawing and in the following description.

The single FIGURE shows an inventive ignition system for internal combustion engines, which has a plurality of combustion cylinders (in the figure, only one ignition system for two combustion cylinders is shown, however, the number of combustion cylinders can be arbitrarily increased.) The combustion cylinders, not shown, are each ignited by spark plugs 1, 2. The spark plugs 1, 2 are connected via lines 3, 4 to secondary windings 5, 6 belonging to ignition coils 7, 8. The ignition coils 7, 8 each have a primary winding 9, 10, which is inductively coupled to the associated secondary winding 5, 6. The secondary windings 5, 6 are connected via lines 11, 12 to a node 13. The primary windings 9, 10 of the ignition coils 7, 8 are connected via lines 14, 15 to a node 16. At node 16, a battery voltage U _B is applied via a line 17. The node 13 in the secondary circuit of the ignition system is connected to a detection device 19 via a current detection line 18. The detection device 19 is connected via at least one Zündaussetz-Zählsignalleitung 20 with a calculation device 21, each of which has at least one Zündungsaussetzzähler Z1, Z2, ..., Zn for each cylinder of the internal combustion engine. The calculation device 21 is connected to an emergency measure control device 23 via at least one emergency measure control line 22. The calculation device 21 controls via control lines 24, 25 switching stages 26, 27, which are connected via lines 28, 29 to the primary windings 9, 10 of the ignition coils 7, 8. The switching stages 26, 27 are, for example, transistors.

When ignition has taken place in a combustion cylinder, an ignition current which flows via the ignition current detection line 18 through the detection device flows via the associated spark plug 1, 2 19 is detected by means of a Zündstromsensors. If a misfire occurs, no sufficiently high ignition current flows at the associated spark plug, so that the detection device 19 can detect cylinder-selectively whether there is an ignition misfire on a specific cylinder. If the detection device detects that an ignition misfire has occurred, it sends an ignition release detection signal via the line 20 to the calculation device 21. The calculator 21 increments the internal ignition count associated with the corresponding cylinder by a variable increment value as it receives, via the line 20, a misfire detection signal for the corresponding cylinder. The increment value is not constant, but depends on the total number of ignition misfires detected for all cylinders in the preceding revolution of the internal combustion engine. For this purpose, the calculation device 21 has an internal memory device 24 in which the number of ignition misfires detected during the last engine revolution is stored.

In a preferred embodiment of the ignition system according to the invention, the variable increment value is calculated by multiplying the stored total number of ignition misfires in the preceding engine revolution by a constant adjustable initial increment factor. For example, the initial increment factor is one default 2 per detected sparkout and will be detected by the detector during a first engine revolution 19 detects three misfires on three different cylinders, the increment value is increased to six. If a misfire is detected again on one of the cylinders in the next engine revolution, its internal misfire counter is incremented with this increased increment value.

With this type of evaluation, the number of misfires per engine revolution is rated. As a result, it is taken into account, for example, that several ignition misfires per rotation are more harmful than ignition misfires, which are distributed over different revolutions. For example, if a complete row of cylinders of an engine, for example six cylinders, increases at an initial increment factor of 2, the variable increment significantly to, for example 12, so that the preprogrammed counter threshold is reached after detecting fewer consecutive ignition misfires to a corresponding emergency measure by the emergency measure Control device 23 initiate. As a result, the reaction rate of the ignition system is significantly increased in a simultaneous occurrence of multiple ignition misfires at different cylinders, so that in particular a measure to protect the catalyst can be initiated quickly. When an internal ignition misfire counter Z _{i of} the calculation device 21 reaches the pre-programmed counter threshold value, the calculation device 21 sends an emergency measure control signal via the emergency measure control line to the emergency measure controller 21, which sends a corresponding countermeasure control signal Emergency action initiates. This emergency measure may for example consist in that the injection for the cylinder in question is turned off.

In a preferred embodiment of the ignition system according to the invention a plurality of internal Zündungsaussetzzähler for different emergency measures are provided for each cylinder. In this case, the respective initial increment factors and the counter threshold values can be set separately for each of the different ignition blanking counters. This makes it possible to perform various measures depending on the determined in the previous revolution ignition misfires.

In a further preferred embodiment of the ignition system according to the invention, the ignition misfires for a plurality of preceding revolutions are stored in the internal memory device 24 of the calculation device 21, so that they can be evaluated by the calculation device 21. This makes it possible to detect periodically occurring ignition misfires on the cylinders and to initiate appropriate measures.

If the storage device 24 is dimensioned correspondingly large, the calculation device 21 can statistically evaluate the ignition exposure behavior of a cylinder over a relatively long period of time and take appropriate measures. For example, the calculation device can issue a warning signal if the statistical evaluation the ignition misfire on a cylinder results in increasing wear of the spark plug.

Ignition system and ignition control method LIST OF REFERENCE NUMBERS:

1 spark plug 2 spark plug 3 management 4 management 5 secondary winding 6 secondary winding 7 ignition coil 8th ignition coil 9 primary 10 primary 11 management 12 management 13 node 14 management 15 management 16 node 17 management 18 management 19 detector 20 Detection signal line 21 calculator 22 management 23 Emergency measure control device 24 control line 25 control line 26 switching stage 27 switching stage 28 management 29 management

Claims (10)

1. Ignition system for an internal combustion engine which has at least two cylinders, with:

   a detection device (19) for detecting the ignition misfires occurring in each cylinder;

   a calculation device (21) which has at least one ignition misfire counter for each cylinder,

   characterized in that, in the event of an ignition misfire in the cylinder which is detected during a revolution of the internal combustion engine, the ignition misfire counter is increased as a function of the total number of ignition misfires in all the cylinders which are detected during the preceding revolution.
2. Ignition system for an internal combustion engine according to Claim 1, characterized in that, in the event of the overshooting of an adjustable fault threshold value by one of the ignition misfire counters, the calculation device (21) transmits for this cylinder an emergency measure control signal to an emergency measure control device (23) for initiating an emergency measure on this cylinder.
3. Ignition system according to Claim 2, characterized in that the injection of a cylinder can be switched off by means of the emergency measure control device (23) as a function of the emergency measure control signal.
4. Ignition system according to one of the preceding claims, characterized in that, in the case of an ignition misfire detected during a revolution of the internal combustion engine, the ignition misfire counter is increased by a variable increment value which is calculated by multiplying the total number of ignition misfires detected during the preceding revolution by a constant adjustable initial increment factor.
5. Ignition system according to one of the preceding claims, characterized in that the calculation device (21) decrements the ignition misfire counter of a cylinder when no ignition misfire is detected for the cylinder during a revolution.
6. Ignition system according to Claim 5, characterized in that the ignition misfire counter is decremented by a constant adjustable amount.
7. Ignition system according to one of the preceding claims, characterized in that a plurality of ignition misfire counters for different emergency measures are provided for each cylinder, the initial increment factors and the respective counter threshold values being adjustable separately.
8. Method for the control of emergency measures in an internal combustion engine which contains a plurality of cylinders, the method having the following steps:

   detection of an ignition misfire for each cylinder occurring during a first revolution,

   calculation of a variable increment value as a function of the total number of ignition misfires detected for all the cylinders during the first revolution,

   increase of an ignition misfire counter belonging to a cylinder by the calculated increment value when an ignition misfire is detected in the corresponding cylinder during a second revolution following the first revolution, and

   transmission of an emergency measure control signal for initiating an emergency measure action to the cylinder when the ignition misfire counter belonging to the cylinder overshoots a specific adjustable counter threshold value.
9. Method according to Claim 8, characterized in that the calculation of the variable increment value is carried out by multiplying the total number of ignition misfires detected for all the cylinders during the first revolution by a constant adjustable initial increment factor.
10. Method according to one of the preceding claims, characterized in that the ignition misfire counter of an associated cylinder is decremented when no ignition misfire is detected for the corresponding cylinder.

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