DE4125677A1 - Fault-tolerant controller for four-stroke combustion engine - extracts different evaluation and control pulse widths from modified camshaft pulse sequence for emergency running - Google Patents

Abstract

The controller uses a pin on the flywheel to produce a reference signal once per revolution of the crankshaft (KW) 62 deg. before TDC of a selected cylinder (I), while the teeth produce 135 pulses per crankshaft revolution. For cylinder recognition a phase detector produces a camshaft (NW) signal of defined tolerance whereby the low-phase pulse widths for particular cylinders (I,VI) correspond to 80 and 35 deg. of crankshaft rotation respectively while those for other cylinders (II-V) are of uniform width corresp. to 57 deg. rotation. ADVANTAGE - Emergency running is guaranteed in event of failure of crankshaft, reference or camshaft signals.

Description

The invention relates to an emergency running control device on an internal combustion engine according to the preamble of the An saying 1.

Modern internal combustion engines come with electronic tax devices operated, in particular the ignition timing and the injection depending on the load and speed control as well as other parameters. For the synchronizer sation of the control system, it is essential that the current Position of the individual pistons in the assigned cylinder exactly determined and with reference to a four-stroke process to the engine electronics is given.

With a burner operated in the four-stroke combustion process engine is known to run the crankshaft in a 4- Clock cycle twice around, whereas the synchronized to the crankshaft driven camshaft only at half speed, that is, only rotates once in the 4-stroke cycle.

The position of the pistons in the cylinders is known Way by measuring the angular position of the crankshaft determined. In a known device there is a the crankshaft driven marker carrier with little at least one reference mark and a plurality on one Circumference of distributed counting marks used. In the The starter ring gear is usually used as a marking carrier  a flywheel, the individual teeth used as Counting marks can be used. There is also a pen or a mark attached as a reference mark. The count markings and the reference mark are marked by one Sensor scanned contactlessly, so that when passing the Reference mark an assigned reference signal and at Passing the counting marks associated with crankshaft sig signals (KW signals) or so-called increment signals will.

When the reference mark appears, this corresponds to one certain, constructively determined angular position of the cure belwelle or the connected pistons. After the appearance the reference mark will be the cure subsequently created Belwell signals counted, with each count a certain th angular position of the crankshaft during the rotary movement corresponds. The accuracy and resolution of these angle measurements solution is essentially dependent on the number of counting marts markings on the marker carrier. In a well-known arrangement Example are 135 teeth of a starter ring gear used as counting marks.

Because of the two revolutions of the crankshaft or two The piston moves up and down in a 4-stroke cycle the angular position of the crankshaft or the piston position in the Cylinders are ambiguous in relation to the 4-stroke cycle. For one optimized, cylinder-selective control, such as a cylinder-selective injection, cylinder-selective ignition adjustment and cylinder-selective knock control, he is required, in addition to the exact angular position of the crank wave information about the assignment in the 4-stroke cycle receive. For this purpose, a device for cylinder detection be knows, which contains a sensor as a phase generator, this when a certain camshaft part or one passes a cam with the camshaft part that is rotatably connected to the cam wave signal (low phase) generated in the 4-stroke cycle only occurs once. This camshaft signal (low phase) has compared to the narrow and precise crankshaft signals or  the reference signal a relatively large width as a tolerance range te of approx. 20 ° KW, corresponding to an assigned aperture Cutout of the panel part.

The geometric assignment between the reference signal sensor and the phase generator is hit so that every second ref limit signal (corresponding to half the speed of the camshaft compared to the crankshaft) within this tolerance range (Low phase) of the camshaft signal.

Only if a camshaft signal occurs at the same time (Low phase) and a reference signal, this reference signal to start the counting process for the crankshaft signals (e.g. 270 increment signals) is used, which means a clear Allocation in the 4-stroke cycle with precise, high-resolution Angle measurement is given on the crankshaft.

The camshaft signal does not immediately become an angle measurement used, but only to make a qualitative statement about the position in the 4-stroke cycle. This is a certain tolerance range of the camshaft signal is possible Lich. With this tolerance range, manufacturing, assembly and Drive tolerances between crankshaft and camshaft is taken into account, ensuring that a reference sig always taking into account all possible tolerances the tolerance range (low phase) of an assigned cam shaft lens signals occurs and thus the simultaneity of both Sig nale is noticeable. A reference signal is thus generated in each case selected in half of the camshaft rotation (low phase of the camshaft signal) and the next, recurring ref limit signal in the other half of the camshaft rotation (High phase of the camshaft signal) suppressed.

As explained at the beginning, the motor control can only be suitable Give control values if you the current position of the individual a piston is entered into the cylinders. It is therefore he obvious that if the crankshaft signals fail, the Refe limit signals or the camshaft signals or the correspond  the sensors the engine control may be significantly impaired can. The aim should be an emergency running behavior with which when it is switched off if one of these signals at least repairs the vehicle maturity, possibly with a reduced range of services, continued can be ren.

In today's systems, however, the failure of one leads Water signals that the internal combustion engine is no longer ge can be started. A continuation of a once started Internal combustion engine is in the event of failure of the crankshaft signals or increment signals are also not possible. In the event of failure of the reference signals can be a once started internal combustion engine machine continue to run at full function as long as no fault signal breaks the synchronization. After such a disturbance tion or after switching off the internal combustion engine he is no longer operational with a new start attempt and the vehicle becomes a breakdown.

The situation is similar if the camshaft sig fails nals, whereby the full function also with a continuation until a false signal or the shutdown of the internal combustion engine machine remains intact. After a malfunction or in a ver Looking for restart, the engine is not operating capable and the vehicle becomes a bed stop here too.

The object of the invention is a generic Steuerein to develop direction so that the emergency running properties ver be improved.

This task is carried out with the characteristic features of the contractor spell 1 solved.

According to claim 1, the camshaft signal is, in particular correspond to the aperture part connected to the camshaft de cutouts designed so that successive further impulse se (low phases) in the number and each one cylinder orders are made available, at least one Im pulse a pulse width different from the other pulses  te has.

In the present application, they are assigned to the cylinders neten pulses as low phases with high pha in between sen claimed and described. It is understood that through Swap the low and high phases the same function is reachable, so that the corresponding reversal also from the An sayings should be included.

With such an arrangement, an essential one is advantageous To achieve improvement in emergency running behavior. It can in addition parts and systems with little modification if necessary conventional designs are used so that the ver improved emergency running properties with practically no or only low additional costs can be realized.

Measures to establish an emergency function in the event of failure the crankshaft signals and the increment signals are in Claim 2 claims. The cylinder is recognized from a comparison of a difference signal, whether this during a low or a high phase of the camshaft signal nals occurs. With a 6-cylinder engine, this can be similar Lich as in the prior art, the cylinder I and / or Cylinder VI can be recognized.

Next is a monotonous one with low and high phases individual cylinders assigned camshaft signal from the simulated individual impulses, for example with falling ones Flank at 62 ° KW before TDC and with a rising flank 5 ° KW before TDC, based on the respectively assigned cylinder. The tax tion, especially of ignition and injection, then as a time system based on the current camshaft signal nals performed.

This is both a start and a continuation in emergency operation possible to run the internal combustion engine. Further are depending on the Aus a sequential, cylinder-selective insertion spraying, a cylinder-selective knock control, a rotie  high or high voltage distribution with double coils or single coils, can be carried out in the emergency operation function.

According to claim 3, it is advantageous to the camshaft signal or to interpret the impulses so that the rising flanks in such a crankshaft angle range that these Flanks can be used directly as starting and emergency ignition angles. Rising flanks in the range 0 ° to 10 ° are suitable for this before OT. This means that these flans can be used as a signal copy ken without further electronic processing for control be used.

The same, rising edges of the camshaft signal can also for setting and adjusting the phase encoder or Camshaft signal sensor can be used. For this, the Engine control during engine running to a start or Brought emergency ignition mode and then the camshaft signal shifted until a connected ignition angle the specified target start / emergency ignition angle (e.g. 5 ° KW before OT) can be read.

With claim 4, the features and measures for an emergency Run function claimed when the reference signal fails. The cylinder is recognized here by counting the increments ment signals during the individual pulses (low phases) of Camshaft signal. Since at least one pulse width Pulse is different from the other pulse widths, can about the correspondingly different number of Incre ment signals the cylinder associated with this pulse width be known.

The high or low edges of the pulses of the Camshaft signal used as trigger marks and for the Calculation of tax data, especially for ignition and Injection, the increment signals occurring from this Trigger marks counted. For example, these can be high or Low edges of the camshaft signal at 85 ° KW or 5 ° KW for Cylinder I and 40 ° KW or 5 ° KW for cylinder VI.  

These measures are taken if the reference signal fails Start and a continuation of the engine securely poses. Depending on the design, the Control device a sequential, cylinder-selective on spraying, a cylinder-selective knock control, a rotie high or high voltage distribution with double coils or single coils are functional.

With the features of claim 5, an emergency run is also Failure of the camshaft signal ensured. With that the reference mark signals are used for the control. There but the camshaft signals are missing is a distinction the cylinder because of the ambiguity of the piston position in the 4-stroke cycle no longer possible. With internal combustion engines with even-numbered cylinders, however, are pairs of cylinders pen recognizable. For example, a 6-cylinder burner engine the groups cylinder I + VI, cylinder II + IV and cylinder III + V recognizable, each at the first and the second crankshaft revolution belong together. For the Emergency operation must be a sequential injection in groups wise, partially selective or parallel injection switched will. If several knock sensors are used, the ignition may be driven with later ignition times in order to Avoid knock damage as the knock sensors belong to the cylinders can no longer be assigned.

This is for internal combustion engines with an even number of cylinders here, too, the start and continuation of the internal combustion engine guaranteed in emergency operation. With the above one restrictions on sequential, cylinder-selective Injection and knock control is a rotating high power supply or dormant high voltage supply with Double coils still functional; a resting high span Power supply with individual coils, however, no longer because the Cylinders cannot be differentiated appropriately.

For internal combustion engines with an odd number of cylinders, for example wise with a 5-cylinder internal combustion engine, is a group  pen-wise summary of cylinders in the ge above described way not possible, so that a continuation the internal combustion engine if the camshaft signals fail is ensured after a malfunction or after a stop however, the internal combustion engine cannot be restarted is.

Using a drawing, the invention with further details units, features and advantages explained in more detail.

Show it

Fig. 1 is a diagram in ° KW for the crankshaft signals or increment signals, the reference signals and the cams wave signals for a 6-cylinder internal combustion engine,

Fig. 2 is a diagram corresponding to FIG. 1, the Notlauffunk tion in case of failure of the crankshaft or representing signals In krementsignale,

Fig. 3 is a diagram corresponding to Fig. 1, the Notlauffunk tion in case of failure of the reference signal,

Represents Fig. 4 is a diagram corresponding to FIG. 1, the Notlauffunk tion in case of failure of the camshaft signal,

Fig. 5 is a diagram corresponding to Fig. 1, which contains two modified th camshaft signals as an adaptation to a 4-cylin der-engine or 8-cylinder internal combustion engine and

Fig. 6 is a diagram corresponding to FIG. 1, which contains a modified camshaft signal as an adaptation to a 5-cylinder internal combustion engine.

In the diagram of FIG. 1, the length for a camshaft revolution (1 NW) corresponding to a 4-stroke cycle and two crankshaft revolutions (1 KW = 360 ° KW) are drawn in in ° KW.

Below are the layers of the top dead at the triangle tips points (OT) for a 6-cylinder internal combustion engine Darge represents with the names of the cylinders in Roman numerals len.

Below are those from the ring gear of a flywheel tested crankshaft signals (KW signals) or increment signals shown by 135 teeth per crankshaft revolution or 270 teeth are derived per camshaft revolution.

The reference signals are shown below the crankshaft signals represents the 62 ° KW before OT in the present example of the first or sixth cylinder. The reference sig Each crankshaft revolution uses a pin generated on the flywheel.

The course of the cam shaft is below the reference signals Lensignals (NW signal) drawn according to the prior art net. The camshaft signal contains a pulse as a low Phase in a tolerance range of 20 ° KW and otherwise runs as a high phase. The assignment between reference signals and Camshaft signals are taken so that the reference signal 62 ° KW before TDC of the first cylinder is selected and the camshaft signal associated with the sixth cylinder (is in a high phase of the camshaft signal) is pressed.

The camshaft according to the invention is in the bottom line represented signal, which, similar to the prior art, has a low phase (I) assigned to the first cylinder is net and a high phase (VI), the sixth cylinder assigned. Similar to the prior art here too (in normal operation) by taking into account Low phases and high phases make a distinction between that first and sixth cylinders are hit. The view production, assignment and adjustment tolerance  zen is through the corresponding window widths of the Low-Sig nals (I) and high signals (VI) are taken into account.

According to the invention, however, compared to the camshaft signal according to the state of the art, the long high phase there structured with impulses in between as low- Phases. In the exemplary embodiment, the low edge of the low Phase (I) at 850 KW before OT (I) and the high flank at 5 ° KW before OT (I). The low phase assigned to the fourth cylinder (IV) starts with its low flank 62 ° KW before OT (IV) and ends with its high flank 5 ° KW before OT (IV). In the same Chen are also the low phases for the cylinder III, II and V in the range 62 ° KW to 5 ° KW before OT. The cylinder VI assigned low phase (VI) is narrower and lies with its low flank at 40 ° KW before OT (VI) and with its high Flank at 5 ° KW before OT (VI). The embodiment lies an ignition sequence I, IV, III, VI, II and V based.

In normal operation, when the crankshaft signals, the Refe limit signals and the camshaft signal without interference there is no difference to the function the prior art, as with the invention Camshaft signal only the distinction between the Reference signals I and the reference signals VI hit becomes. The different lengths of the low phases can each but also in normal operation for a reduction in time for desynchronization after the start of currently maximum 1 camshaft rotation to a maximum of 1/2 camshaft rotation 1 crankshaft revolution can be reduced. This can be done by tough the crankshaft signals in different lengths Low phases, which are assigned to cylinders I and VI, he will be enough:

A reliable detection for cylinder I results from that Occurrence of a reference signal in the low phase (I), where this low phase (I) is simultaneously greater than (in the present Example) 51 is subsequent crankshaft signals.  

A reliable detection is also possible for cylinder VI. Here the assigned reference signal is in a high phase, the subsequent low phase (VI) being smaller at the same time as z. B. 31 crankshaft signals or occurring increment signals.

This means that the motor control can be safely on every reference signal nal start what the maximum synchronization time halved.

In Fig. 2, the limp home function in the event of failure of the crankshaft lens signals (failure indicated by dashed lines) is shown.

The detection of cylinders I or VI takes place in the vorbe type from the comparison of whether the reference signal was occurs during a low phase or high phase.

The camshaft signal is in a connected Schaltge advises evaluated and in a "monotonous camshaft signal" set as shown in the diagram. The implementation takes place in such a way that all low phases are made of the same length (only the are different in the example long low phases for cylinders 1 and VI). The Low flanks are 62 ° KW before OT and the high flanks Flanks 5 ° KW before OT. This monotonous camshaft signal or the edges of the low signals are used to control ignition, Injection, etc. as a pure time system based on the current camshaft signal. In emergency running he there is only a less good resolution of the Measurement for crankshaft position; otherwise the others are all control functions.

In Fig. 3, the limp home function is shown when the reference signal fails.

The detection of the cylinder I or the cylinder VI is carried out by counting the crankshaft signals in the associated, different long phase low phases, the low phase (I) of a length of 80 ° KW and the low phase (VI) of a length of 35 ° KW corresponds. The low phases in between correspond to a length of 57 ° KW. Converted to 135 crankshaft signals or increment signals per revolution of the crankshaft, 80 ° KW = 6 ° increments; 57 ° KW = 42 increments and 350 KW = 26 increments. Taking into account the possible tolerance positions of the (missing) reference signals within the camshaft signal phases, there is a reliable statement for the detection of cylinder I if the number of increments is greater than or equal to 51 and for cylinder VI if the number of increments is less than or equal to 31 is as shown in FIG. 3. In the present example, the high edge of the low phase (I) is used as a trigger mark for triggering the control or for calculating the ignition times, etc., the crankshaft signals occurring from this trigger mark being counted. These crankshaft lens signals or incremental signals are derived from the 135 teeth per crankshaft revolution, so that an increment corresponds to 1.33 ° KW.

In Fig. 4, the limp home function in the event of failure of the camshaft lens signal is shown. Only cylinders I and VI can be seen; a distinction is not possible. The control is triggered directly by the reference signal or the second edge of the reference signal at 60 ° CA before TDC (I or VI). From this edge whoever counted the KW signals occurring.

The control for the ignition is used for emergency operation and / or injection made for pairs of cylinders, wherein according to the firing order, cylinder groups I + VI, II + IV and III + V are taken together.

So far, the invention has been explained using a 6-cylinder internal combustion engine. In Fig. 5, the transfer or adaptation solution of the invention to a 4-cylinder internal combustion engine and an 8-cylinder internal combustion engine is shown.

In the middle area of FIG. 5, the TDC positions for a 4-cylinder internal combustion engine are shown, each of which is 180 ° KW apart. Depending on the number of cylinders, four low phases of the camshaft signal are required.

The low phase (I) is also in the range from 85 ° KW to 5 ° KW before OT (I). The low phases for cylinders II and IV are in the range 62 ° KW to 5 ° KW before OT (II or IV) and the low phase (III) is in the range from 40 ° KW to 5 ° KW before OT (III). With this formation of the camshaft signal is an emergency operation for a 4-cylinder internal combustion engine speaking of the detailed example for a 6- Cylinder internal combustion engine possible.

In the lower area of Fig. 5 are shown the TDC positions for an 8-cylinder internal combustion engine and an adapted, erfindungsge Permitted formation of the camshaft signal, the 8 cylinders 8 low phases being accordingly required.

In the lower area of FIG. 6, a suitable modification of the camshaft signal for a 5-cylinder internal combustion engine is shown. The TDC positions for the individual cylinders are offset by 144 ° KW. The low phase (I) is in the range 85 ° KW to 10 ° KW before OT (I). The remaining low phases are in the range 62 ° KW to 10 ° KW before TDC.

In summary it is stated that with the invention a Control device is provided with which too if one of the crankshaft signals fails, reference signals or camshaft signals an operation of the internal combustion engine is possible in an emergency function, with most Designs of internal combustion engines both continue and also guarantee a new start of the internal combustion engine is steady.

Claims (5)

1. Runaway control device on an internal combustion engine,
with a driven in a four-stroke combustion process NEN crankshaft that rotates twice in a 4-stroke cycle (2 KW) and one at half speed, accordingly only one revolution (1 NW) in the 4-stroke cycle, syn chronically driven camshaft,
with a device for determining the angular position of the crankshaft, which has a marking carrier driven with the crankshaft, with counting markings distributed along a circumference, in particular a starter ring gear with the teeth as counting markings, and a first sensor when the counting markings pass by assigned crankshaft signals as increment signals dispenses and
which also has a reference mark, in particular a pin on the flywheel, at 62 ° KW before TDC from Zylin I, and a second sensor emits a reference signal once per crankshaft rotation when the reference mark passes,
with a device for cylinder detection or for the assignment of the position of the crankshaft and the associated piston in the 4-stroke cycle, which contains a third sensor as a phase generator, which is a passage part when a certain camshaft part or a rotary part connected to the camshaft Camshaft signal (NW signal) with a pulse of a certain tolerance range (approx. 20 ° KW) generated as a low phase and in the rest of the course as a high phase, the assignment between the reference signal sensor and the phase generator being made so that every second Reference signal corresponding to half the speed of the camshaft relative to the crankshaft is within the tolerance range of the camshaft signal (NW signal), where a reference signal is selected in one half of the camshaft rotation (low phase of the camshaft signal) and the next, recurring reference signal in the other half of the camshaft revolution suppressed (high phase of the Noc kenwellensignal), characterized,
that the camshaft signal or a diaphragm part connected to the camshaft is designed by appropriate cut-outs so that successively further pulses (low phases) in the number of cylinders and in each case one after the other are assigned to a cylinder, the at least one pulse (Low phases I and VI) has a different pulse width to the other pulses (low phases II to V). 2. Runaway control device according to claim 1, characterized in that
that in the event of failure of the crankshaft signal or the incre ment signals, the emergency operation is carried out in such a way that the cylinder is recognized by evaluating a reference signal as to whether this occurs during a low phase or a high phase of the camshaft signal and
that a monotonous, with low and high phases assigned to the individual cylinders camshaft signal from the individual NEN pulses (low phases I to VI), in particular with falling edge 62 ° KW before TDC and with a rising edge 5 ° KW before TDC, based on the respectively assigned cylinder, is simulated and that the control, in particular ignition and injection, is carried out as a time system on the basis of the instantaneous camshaft signal. 3. runaway control device according to claim 1 or 2, characterized, that the camshaft signal or the pulses (low phases 1 to VI) are designed so that the rising edges (High edges I to VI) in such a crankshaft win range (e.g. 0 ° to 10 ° before TDC) that this flange ken directly (as a signal copy) as the starting and emergency ignition angle are usable. 4. Runaway control device according to claim 1, characterized in that
that in the event of failure of the reference signal, the emergency operation is carried out in such a way that the cylinder detection takes place by counting the crankshaft signals or incremental signals during the individual pulses (low phases I or VI) of the camshaft lens signals, and thus the associated pulse width due to the different pulse width of at least one pulse Zy linder is recognizable,
that the high edges or low edges of the pulses (high edges I) of the camshaft signal are used as trigger marks and
that the crankshaft signals or increment signals are counted from these trigger marks for the calculation of the control data, in particular for the ignition and injection. 5. Runaway control device according to claim 1, characterized featured, that if the camshaft signal (NW signal) fails, the Emergency running is carried out in such a way that for ignition and / or Injection cylinder groups, especially in pairs (I + VI; II + IV; III + V) are controlled, one sequential injection in a group, partial sel tive or parallel injection is switched.