JPH07502093A - How to control closing time - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] How to control closing time Conventional technology The present invention provides a closure system for an ignition system for an internal combustion engine according to the generic concept of claim 1. Concerning time control methods.

Control of the closing time for internal combustion engines is described, for example, in German Patent Application No. 3402 It is already known from specification No. 537. This control uses two comparators and two Reference marks are used to set the ignition point and control the closing time. this In this case, the control of the closing time is based on the monitoring of the ignition coil current using two comparators ( One of these responds when 80% of the required ignition coil current is reached, the other at 10%. (responses when it reaches 0%). In this case, the individual comparators The time taken to reach the data threshold must be constantly measured, and this measurement The charging time must be calculated from the time taken. This is a drawback. this hardware required for the solution (80% - comparator and 100%) % - comparator) and special demands on the processor as well as the required software. requires relatively high costs. Additionally, unpublished patents from the Federal Republic of Germany have been published. A method for adjusting the closing time is known from Application No. 411,970. this place In this case, one comparator is provided. Depending on this comparator, the ignition The current strength of the ignition lamp is compared with the target value, and the comparator output level is set at each ignition point. detected.

In this case, the energy stored in the ignition coil is sufficient to obtain a normal ignition spark. It is detected whether the

Here, the control device closes the comparator based on the respective output level. An approximation to the optimal closing time is achieved by incrementally lengthening or shortening the closing time. .

However, this method cannot quickly detect the desired closing time.

This can result in either an excessively slow closing time (which results in unnecessary power loss) or an excessive A short closing time (which causes a misfire) will be output.

Advantages of invention The advantages obtained by the method according to the invention as defined in the characterizing part of claim 1 are: , the time measurement of the output closing time and the time measurement until the comparator responds. By doing this, the optimum opening time can be determined and the output can be made at the time of subsequent ignition. It is.

Advantageous embodiments and refinements of the invention are described in the dependent claims. Particularly advantageously, The comparison voltage supplied to the comparator is determined by the predetermined current value of the charging characteristic curve of each ignition coil. It can be adjusted to This allows the method to be adjusted to different engine operating points. It is possible. Further advantageous special table 17-502093 (3) In this case, the forced point is triggered for a predetermined time after the comparator responds. This results in high Unnecessary burden on the voltage guide section and unnecessary large output loss are eliminated. Furthermore, the relevant The advantage that the method has is that by monitoring the comparator output a predetermined minimum closing time is to be ensured.

Additional diagnostics can now be carried out on the basis of plausibility tests.

This minimum closing time is checked. This way, for example, the occurrence of a short circuit can be identified and the corresponding Ignition and fuel injection are interrupted to protect the catalyst and ignition stage for cylinders that Ru. When restarting the engine, the final engine The opening time at the time of stop is retrieved. This operating process is preferably carried out at engine temperature T.

, is done depending on. Therefore, the engine temperature at restart T□1. is the predetermined value The engine temperature T at the final engine stop. 1. only if it exhibits a deviation from , the closing time at the final engine stop is used as the closing time at restart.

drawing Embodiments of the invention are illustrated in the drawings and explained in detail in the specification below.

FIG. 1 is a block circuit diagram of a circuit arrangement for detecting an ignition coil current. Figure 2 shows when closed. FIG. 3 is a diagram showing the time elapsed characteristics during period detection. Figure 3 shows the flowchart for detecting closing time. -This is a chart. Figure 4 shows ignition for two closing times depending on engine temperature. It is a figure showing coil current.

Description of examples FIG. 1 shows a control for the ignition stage of an ignition system of an internal combustion engine, not shown here. The microprocessor 1 of the device is shown. This microprocessor 1 is connected It is connected to the base of the ignition transistor 3 via a line. The ignition truck The collector side of the register 3 is connected via the primary winding of the ignition coil 4 (not shown here). It is not connected to the battery voltage U, for example of the vehicle battery.

The secondary side of the ignition coil is connected on the one hand to the battery voltage U, and on the other hand to the spark plug 5. It is connected. The emitter side of the ignition transistor 3 is the inverted input of the comparator 6. connected to the power side, and further connected to ground through measuring resistor 7 in parallel with this. There is. The non-inverting input side of comparator 6 is formed on the one hand by resistor 8.9. It is connected to ground via a voltage divider and on the other hand to the supply voltage U.

This supply voltage U is supplied by a regulated voltage power supply, not shown here.

The comparison voltage Uv at the non-inverting input of the comparator 6 is adjusted via a voltage divider. child In this case one comparator can be connected to several separate ones, e.g. as shown in Figure 1. It is also possible to use it with voltage dividers 8a, 8b or 9a, 9b. in this case are different comparison voltages U1. do not have U7. is adjusted in the comparator 6 via the switching elements 11a and llb. It will be arranged. What is at stake for the comparator, i.e. the comparison value that should be reached? What percentage of U (e.g. 90%...95%) when the comparator The period from the start of the closing time to the end of the closing time, depending on whether the is detected for a part of the predetermined period. only suggested here The further power stage of the ignition device is integrated with the emitters of the individual ignition transistors. connected so that In internal combustion engines where the closing angles overlap, Another evaluation with cylinders with components 6 to 9 with overlapping mutual closing angles Should be evaluated separately by the circuit. The output level IP of comparator 6 is is supplied to the microprocessor 1.

Figure 2 shows the temporal signal course evaluated by the microprocessor. Ru. The signal curve in the upper part of FIG. 2 is caused by the microprocessor 1 via the connection line 2. The signals for controlling the ignition power stage 3 are shown.

At time T1, the microprocessor switches the signal ts from 0 to 1. This closes The starting point of the creation time is determined.

The microprocessor 1 measures (calculates) this time T1 and determines the starting point (base). (times for various events are measured from this starting point) ). The microprocessor 1 also controls the end point T2 of the closing time (this end ignition is performed at this point in time), and this closing time 5Z (=71 to T2) is during the ignition cycle or the microprocessor, e.g. during a restart. fixedly set depending on e.g. engine temperature or another operating parameter It is something that will be done. It is shown between the closing time start point T1 and the M closing time end point T2. The period TDIA represents the minimum closing time. This minimum closing time is constant. This is used to identify short circuits.

The lower signal string in FIG. 2 shows the output level IP of the comparator 6. here When the predetermined ignition coil current is reached via the comparison voltage Uv, the control is switched on. The output of the comparator switches from 0 to 1.

If the ignition coil target current is reached at time T3, period t4 starts. start. At the end of this period t4, the upper microprocessor 1 The closing time ends.

Figure 3 shows a flowchart for processing the detected time as shown in Figure 2. It is shown. The microprocessor 1 processes the measured parameters (e.g. rotation speed, Calculate the ignition point based on the temperature, pressure, etc. For each ignition cycle of an internal combustion engine In processing step 20, the microprocessor 1 determines that the signal train ts corresponds to the ignition stage. Monitored for control of comparator output level IP.

Subsequently, in the timing step 21, it is checked whether there is a start T1 of the closing time. . If there is a start, Yes in the timing step 21 - the processing step is started from the output side. Proceed to step 22. In this processing step 22, the closing time start point T1 is used for subsequent calculations. It is intermediately stored as the base time for. Opening time start T1 not detected If so, proceed to the adjustment step 23 from the No-output side of the adjustment step 21. Here, the presence or absence of an ignition event, that is, the presence or absence of the end of the closing time T2 is detected. be done. Yes-output of the relevant timing step 23 if an ignition event is detected. Proceed to step 33 from the side. Here, the output level IP of comparator 6 is , after ignition (in this case switching time and discharge time are taken into account in Uni) response state It is checked whether it has an output level corresponding to the state (IP-1). have If not, that is, if the predetermined period after ignition (IF) = 0, then N o - Proceeds from the output side to the alignment step 24, in which the comparator It is checked whether the controller 6 has responded completely. In other words, the response of comparator 6 is It is determined whether or not the period T3 has been reached. The response of the comparator is This is carried out at the moment when the signal has stored energy corresponding to a predetermined comparison value Uv. makeshift station Depending on the Yes-output of step 24 (=when the comparator responds), the subsequent processing In processing step 25, the intermediate stored value T1 and the comparator for the start of the closing time are the subsequent point in the ignition coil in question based on the time T3 for the response of the The closing time SZ for the fire cycle is determined. In this case SZ,=T3-Tl It is.

No-output of timing step 24 (= when comparator 6 is ignited or closed) If there is no response at the end of the time interval T2), the process advances to the time adjustment step 26.

In this alignment step 26, the measured actual closing time (T2-TI) precedes The optimum closing time calculated by the microprocessor 1 in the engine cycle of It is checked whether it is greater than (SZ). Measured actual closing time (T2 -Tl) was calculated by the microprocessor 1 in the previous engine cycle. If it is not larger than the optimal closing time (SZ), e.g. after calculation or closing time If the engine is heavily loaded after delivery and the ignition timing shifts forward in time In this case, the process proceeds to processing step 27 from the No-output side of the timing adjustment step 26. child Similarly, in the timing step 27, the desired optimal closing time SZ is determined for the subsequent ignition. (SZ,=SZ). Case like this (SZ,=SZ) is, for example, when the internal combustion engine is idling and is not actually required. The ignition coil energy applied is less in the part load range or in the full load range. Occurs when If the timing step 26 is Yes-output, that is, the actual If the closing time (T2-Tl) of is larger than the desired opening time (SZ), In process step 28, the subsequent desired optimal closing time SZ is determined as follows: It will be done. That is, adding the correction value K to the sent closing time (T2-TI) (SZ,=T2-T1+K). This is the response of comparator 6. It's to get it. In this case, the correction value shall be determined by applying it to each engine type. This is the value given. This correction value determines the ignition coil current by the closing time of subsequent ignitions. It is ensured that a predetermined value of flow is achieved. In this case, the relevant amendment IIK shall be made at once. It is not added all at once (the actual closing time of the sidewalk is divided into multiple will be added accordingly.

If the interval 23 for the period T2 is a No-output, that is, an ignition event is detected. If not, then in an alignment step 29 the signal sequence IP is also It is checked whether a rising edge (i.e. comparator response) is occurring. . If a rising edge has occurred, in processing step 30 the comparator 6 The response time T3 is temporarily stored. In the subsequent adjustment step 31, the comparator The response time T3 of the regulator 6 is the minimum closing time T. It is checked whether it is smaller than 1A. Ru.

If the result of this adjustment step 31 is Yes, the process proceeds to processing step 32. This process In step 32, the fact is determined as the occurrence of a short circuit in the ignition device, and Accordingly, ignition and fuel injection are interrupted in the corresponding cylinder. If the timing step 33 outputs Yes after the response of the comparator 6 when If the comparator is still responsive after ignition, the subsequent A defect in the comparator is identified in process step 34 and process step 35 , the closing time is determined by a microprocessor, e.g. It is sent out based on the battery voltage. In the adjustment step 29, the comparator output A rising edge is identified in the signal sequence IP after a change in the signal on the power side. If so, in a subsequent alignment step 36 the signal sequence IP=1 is It is checked whether this is true, ie whether the comparator has already reacted. this If the output of the adjustment step 36 is Yes, the process proceeds to an adjustment step 37. this In the adjustment step 37, the period t4 (which is Maximum allowable closing time SZ, .

) has elapsed. If the The corresponding closing time is terminated by the microprocessor 1 at time T4 in step 38. forced ignition is triggered. This eliminates unnecessary loads on the high voltage guide. Avoidance is guaranteed.

Arrangement step 36, arrangement step 37.31, and processing steps 38, 32 , 35, 25, 28. In the case of No- output of 27, go to processing step 39, respectively. You can proceed. In this processing step 39, the times stored for the ignition cycle in question are Intervals TI and T3 are erased. Subsequently, in process step 4o, the next ignition signal is Closing time detection for the cycle is newly started.

According to the method described above, it is possible to detect the closing time very accurately. because Measured times are directly mapped instead of unnecessary conversions to angular levels. This is because it is used by the microprocessor to detect the opening time.

Furthermore, the method allows for a very good response to dynamic characteristics. . Thereby, the dynamometer that occurs after the start of the closing time, e.g. by a microprocessor. The difference between the desired closing time SZ and the actual closing time is Detected as a difference between the observed closing time (T2-Tl) and the subsequent ignition The closing time s28 of the cycle is adjusted accordingly to the measured period. closing time Errors in detection can occur due to dynamic characteristics even under changing operating conditions. to be avoided.

FIG. 4 shows the temperature dependence of the increase in ignition coil current. In this case, the characteristic Curve A shows the rise in current in the original ignition coil at relatively low temperatures. . Furthermore, in contrast, due to characteristic curve B, the ignition coil at the end of the relatively high temperature An increase in current is shown. An increase in temperature from a relatively low temperature to a relatively high temperature or when the temperature decreases from a relatively high temperature to a relatively low temperature. The ohmic resistance inside the coil changes. This also changes the rate of increase in the ignition coil current. do. If the internal combustion engine comes to a standstill here, the engine temperature will normally be Since it is relatively high, the closing time determined for characteristic curve B is memorized. Enji When the engine is restarted, the period t2 is first used as a basis for the detection of the closing time. However, The ignition coil current increases when the engine cools down and the ohmic resistance decreases. Due to the increasing steepness, the comparator reacts at a significantly earlier point in time, e.g. at time t1. Ru. This results in a relatively long closing time for the first closing time after restarting the engine. time (which is shown by the characteristic curve C) is sent out, but the subsequent closure Under the formation time, the instantaneous value of the closing time occurs immediately.

international search report ρCT/DE 92101047

Claims (9)

[Claims] 1. Internal combustion engine with a microprocessor for control of at least one ignition stage A method for controlling the closing time of an ignition device in Seki, detecting the current flowing through the ignition coil and supplying it to a first input side of the comparator; A predetermined comparison voltage is applied to the second input side of the comparator, Closing time control that supplies the output level of the comparator to the microprocessor In the method, the microprocessor (1) determines whether the closing time starts (T1) or not. The period from the time to the response time (T3) of the comparator and the closing time when ignition occurs Measure the period up to the end of the period (T2), Measured period from the start of the closing time (T1) to the comparator response time (T3) (T3-T1) is the closing time (SZa) or the measurement period (T3-T1) is the closing time (SZa). Perform an evaluation such that a part of the period determined from 1) is the closing time (SZn), The relevant closing time (SZ■) is calculated as the optimum closing time for the subsequent ignition (SZ■=T3- T1) is sent by the microprocessor (1) to the ignition stage by a corresponding signal. A method for controlling closing time, characterized in that: 2. At least one comparison voltage (Uv) applied to the comparator (6) adjustable to a predetermined current value in the charging characteristic curve of each ignition coil; The method according to claim 1. 3. Using the response time (T3) of the comparator (6), the closing time end time (T The period (t4) for monitoring 2) is started by the microprocessor (1). and the closing time end point (T2) is missing after the relevant period (t4) has elapsed. Forced ignition is triggered by the microprocessor (1) if the The method according to item 1 or 2 of the scope. 4. When restarting the engine, the measured engine temperature at the time of restart (T■■■■ ) deviates from the engine temperature (T■■■■) at the end of operation by a predetermined value. The opening time (SZn) determined in the last engine cycle is used only if 4. A method as claimed in any one of claims 1 to 3, in which a start-up is initiated. 5. Measurement from the start of the closing time (T1) to the comparator response time (T3) If the period is shorter than the predetermined minimum closing time (TDIA), then It is determined that this has occurred, and ignition and fuel injection are interrupted for the corresponding cylinder. , the method according to any one of claims 1 to 4. 6. The microprocessor (1) executes the command at the end of the closing time (T2). Regarding the presence or absence of a response from the comparator (6), the output level (I P) is queried, At this point, there is no response from the comparator and the signal is reset based on the sent closing time (SZ). If the actual closing time (T2-T1) is longer or the same, then the delivered closing time At subsequent closing by adding the correction value (K) (SZn = T2 - T10K) The method according to any one of claims 1 to 5, wherein the distance (SZn) is set. . 7. The correction value (K) is determined by the comparator when the correction value (K) is applied. as set forth in claim 6, which is a value that can be set to ensure that the Method. 8. The correction value (K) is added stepwise to the actual closing time (T2-T1). , the method according to claim 6 or 7. 9. There is no response from the comparator (6) and the actual closing time (T2-T1) is shorter than the relevant sent closing time (SZ), then the subsequent closing time (SZ) In the claims, the previous delivered closure time (SZ) is sent out again as Zn) The method according to any one of Items 1 to 6.