JPS60230564A - Ignition timing controller for multicylinder engine - Google Patents

Abstract

PURPOSE:To prevent the occurrence of knocking so effectively, by dividing such a cylinder group that knocking is estimated among all cylinders into subgroups, while compensating the ignition timing of some cylinders alone in the same group in which the knocking happened to the timing lag side simultaneously. CONSTITUTION:This controller is provided with a knocking detection circuit 13 which detects the occurrence of knocking from output of a vibration sensor 9 for detecting an engine vibration. On the basis of output of a crank angle sensor 8, those cylinders under an explosion stroke are discriminated, and with the discrimination result and the output of the knocking detection circuit 13, it is also provided with an MPU10 compensating the ignition timing of these cylinders concerned. The MPU10 is constituted to compensate the ignition timing of other cylinders being correlative as to the occurrence of knocking to the timing lag side as far as the specified value on the basis of the comparative discrimination result between the detected knocking level and the reference level and the cylinder discrimination result. With this constitution, the knocking of the other cylinders where knocking occurrence is estimated is made so as to be preventable before it happens.

Description

[Detailed description of the invention] [Industrial application field] The present invention detects engine knocking.

The present invention also relates to an ignition timing control device for a multi-cylinder engine for correcting the ignition timing to an optimal state where knocking does not occur.

[Prior art]

When knocking occurs in an engine, it causes overheating and a decrease in output and efficiency. Therefore, preventing knocking from occurring is very important in improving the durability, output, fuel efficiency, etc. of the engine.

In general, the engine's ignition timing is advanced to the knock limit so that it is the optimal timing for the operating condition, but if the ignition timing is advanced too much, knocking is likely to occur, and to prevent this, the ignition timing must be retarded. It is necessary to do so.

In a multi-cylinder engine, as a conventional example of a device that controls ignition timing, a knocking detection circuit detects a knocking condition for each cylinder, and the ignition timing of each cylinder is delayed depending on the detected knock level. A type with an angular shape (Japanese Patent Publication No. 56-50114) is known.

However, in operating ranges where knocking is likely to occur, such as when the engine is running at high load and low speed, the knock level is relatively large, and when a high level of non-king occurs, knocking tends to occur in other cylinders as well. In the above conventional example, even though it is possible to predict the occurrence of non-king in other cylinders based on the non-king occurring in one cylinder, ignition is only performed in the cylinder in which non-king has actually occurred. Since it is configured to perform timing correction, the correction tends to be delayed as a whole, and there is a drawback that knocking occurring in other cylinders cannot be prevented.

As an alternative to such conventional examples, the applicant of the present application has proposed that when knocking is less than a predetermined level, the ignition timing is corrected for each cylinder in which non-king occurs, as in the conventional example; When knocking occurs, the ignition timing is corrected not only for the cylinder where knocking occurred but also for all other cylinders (Japanese Patent Laid-Open No. 58
-166574) was proposed earlier.

However, the phenomenon that when knocking occurs in one cylinder at a predetermined level or higher, knocking also occurs in other cylinders does not hold true among all cylinders, but actually only among cylinders with almost equal intake conditions. It is true.

In other words, when looking at a 4-cylinder engine, for example.

The cooling conditions of each cylinder are not necessarily the same.

Since the cylinders on both sides (1st and 4th cylinders) have better cooling performance than the middle part (2nd and 3rd cylinders), their knocking limit is higher than that of the middle part. or.

The amount of air-fuel mixture and air-fuel ratio taken into each cylinder differs depending on the shape of the intake manifold and other factors. From this, in the above proposed example, when knocking at a predetermined level occurs in one cylinder.

Regarding the occurrence of non-king, the ignition timing must be corrected even for cylinders that are not related to each other, which has the drawback of unnecessarily correcting the ignition timing, which was originally in an optimal state.

[Purpose of the invention]

The present invention solves the above-mentioned inconveniences by dividing the cylinders in which non-king is expected to occur out of all the cylinders into groups in advance, and simultaneously timing the ignition timing of only the cylinders in the same group where non-king has occurred. An object of the present invention is to provide an ignition timing control device for a multi-cylinder engine configured to correct the ignition timing to the retarded side.

[Structure of the invention]

The ignition timing control device for a multi-cylinder engine according to the present invention includes: a knocking detection means for detecting knocking from engine vibration; a cylinder discrimination means for discriminating which cylinder is in an explosion stroke among the plurality of cylinders from the crank angle of the engine; first ignition timing correction means for correcting the ignition timing of the cylinder corresponding to the output based on the output of the means and the output of the cylinder discrimination means;

Non-king level determining means compares the knocking level obtained by the knocking detecting means with a predetermined reference level, and the non-king level is determined to be at the reference level by the output of the non-king level determining means and the output of the cylinder determining means. In the above case, a second ignition timing correction means is provided which retards the ignition timing of another cylinder by a predetermined amount in advance, the intake condition of which is almost the same as that of the cylinder in which the non-king has occurred, that is, which is in a mutual correlation with respect to the occurrence of knocking, The first ignition timing correction means prevents the cylinder in which knocking has occurred from causing non-king at the next ignition timing, and
The second ignition timing correction means can quickly control the ignition timing of each cylinder to the optimum state by preventing knocking in other cylinders where knocking is predicted to occur based on the cylinder in which knocking has occurred. It is characterized by the following.

〔Example〕

An embodiment of the present invention will be described in detail below with reference to FIGS. 1 to 6.

In this embodiment, as shown in FIG. 1, the first to fourth cylinders 1a
This is applied to a four-cylinder engine 2 having a diameter of ~1d. In Fig. 1, the controller 3 of the 2 ignition timing control device
Based on the ignition timing control signal output from the ignition timing control signal, a high voltage from the ignition coil 5 is sequentially applied via the distributor 6 to the spark plugs 4a to 4d provided corresponding to the cylinders la to 1d, respectively. It is configured as follows.

An air flow sensor 7 provided in the middle of the intake passage is configured to detect the amount of intake air into the engine 2 and input this to the controller 3.

The crank angle sensor 8 is configured to detect the crank angle of the engine 2 and input it to the controller 3. Further, the vibration sensor 9 detects vibrations of the engine 2. 'Figure 2 shows the controller 3 in Figure 1.
The configuration is shown in more detail in a block diagram,
An MPU (microprocessing unit) 10 performs various arithmetic operations.

A signal regarding the amount of intake air taken out from the air flow sensor 7 is converted into a digital signal by an A/D converter 11 and input to the MPU 10. The output of the crank angle sensor 8 is shaped by a waveform shaping circuit 12 into three waveform pulse signals shown as A, B, and C in FIG. 3, and each of the pulse signals is input to the MPU10.

In FIG. 3, the signals to the waveforms are the four cylinders la to 1d.
Among them, the signal has a pulse width corresponding to a predetermined section in which the first cylinder 1a is in the explosion stroke. Further, the signal of waveform B is a pulse signal corresponding to the top dead center (TDC) of each cylinder 1a to 1d. The signal of waveform C is a signal delayed in phase by 60 degrees from the signal at the top dead center (TDC).

A signal indicating the magnitude of engine vibration taken out from the vibration sensor 9 is input to a knock detection circuit 13 consisting of an integrator, etc., and is configured to detect the magnitude of knocking based on the level of the integrated value. This knock detection circuit 13 is reset by the signal B of the top dead center TDC, receives the output of the vibration sensor 9, and is 60 degrees A after the top dead center.
The input is blocked by the signal C of TDC 60°, and the integral value at that time is held. Therefore, the output of the knock detection circuit 13 has the waveform shown by D in FIG. The output of the knock detection circuit 13 is converted into a digital signal by the A/D converter 14 at the secondary stage, and then sent to the MPU.
This is input to l0.

In addition, a timer 115 consisting of a free running counter
．． ROM (read-only memory) 16° and RAM (
random access memory) 17.

Each is input to the MPU10.

Based on the input of each of the above signals, the MPU
The signals regarding the ignition timing of each cylinder 1a to 1d calculated in l0 are sequentially output from MPU l0 to timer 18 so that the primary stage drive circuit 19 is driven at every set time of timer I [18]. It is configured.

FIGS. 4 to 6 are flowcharts of the arithmetic processing performed in the MPU10, and the operation will be explained below based on these figures.

FIG. 4 shows the main routine of the arithmetic processing described above, which is constantly repeated while the engine 2 is in operation.

In this main routine, the R
There is a step 2o for setting AM17 and other states to initial states, including included routine 1 in FIG. 5, which will be described later.
Step 21 of calculating the rotational speed ne of the engine 2 based on the top dead center period TO calculated in Step 22 of inputting the signal QA regarding the intake air amount converted into a digital signal by the A/D converter 11, Basic ignition timing (ATDC60) corresponding to signal QA and engine 2 rotation speed ne
Step 23 of reading out T1 corresponding to QA and ne from the ROM 16 which stores a map in which T1 (time from ' to next ignition) is made into a table and related to each other is sequentially and repeatedly executed.

Included routine 1 shown in FIG. 5 is executed once every time the TDC signal is input to MPU10. In this routine, the time t1 at which the TDC signal is input is read from the timer 115 in step 24, and the previous TDC time t2 is subtracted from the TIC time t1 in step 25, and the difference is calculated as TDC.
It is temporarily stored as the period T'O. The TDC period TO determined in step '25 is used in step 21 of the main routine. In addition, in step 26, the previous TDC time t is rewritten to the currently read TDC time t1, and in step 27, the above TDC time t is rewritten to the currently read TDC time t1.
It is determined whether the DC signal corresponds to the fifth first cylinder 1a, and whether it corresponds to the first cylinder 1a is determined by whether or not the signal of waveform A is input to MPU10 at this time. be done. Then, the TDC signal at this time is the first
When it corresponds to the first cylinder 1a, the cylinder identification number NC for identifying the cylinder is set to 0 in the first step 28, and when it does not correspond to the first cylinder 1a (there is no signal input of waveform A), another step 29 sets the cylinder identification number NC to 0. 1 is added to the previous value.

That is, when the first cylinder 1a reaches the TDC point, NC-03
When the next cylinder to be fired reaches the TDC point, NO-2,
When the next cylinder reaches the TDC point, it becomes NO-2, and when the next cylinder reaches the TDC point, it becomes NO-2, and when the first cylinder 1a reaches the TDC point again, it returns to NO-2. In this embodiment, the firing order of the cylinders 1a to 1d is 1st → 3rd → 4th.
→The second order, therefore, the NC value and each cylinder are related as shown in Table 1.

Table 1 Figure 3 shows the level of the NC size.

The relationship with other signals A, B, C, and D is shown.

The included routine 2 shown in FIG. 6 is ATDC6
0'' signal is input to MPU10. In this routine, the knock detection signal [[
)-t-Accepted to MPUIO 5 In the next step 31, it is determined whether or not there is knocking. When it is determined that the knock detection signal is at O level, that is, there is no knocking, the retard amount TR (NC) of the corresponding cylinder, that is, the basic ignition timing TI (determined in the main routine) is determined in step 32.
The correction amount that determines how much to delay is the predetermined amount △
Only TR is rewritten to be smaller than the previous time. As a result, the ignition timing is corrected to the advanced side, but the correction to the advanced side is limited so as not to exceed the basic ignition timing TI.

On the other hand, if it is determined in step 31 that there is knocking, the retard amount TR (NC) of the corresponding cylinder is rewritten to be larger by a predetermined amount ΔTR in another step 33.
The ignition timing when this cylinder next ignites is delayed by the above correction amount, thereby preventing knocking from occurring.

If it is determined in step 31 that there is knocking, the knock detection signal is further compared with a predetermined reference level KN (0) in step 34. At this time, if it is determined that the non-king level is smaller than the reference level KN(0), the process proceeds to the first step 35. Conversely, in step 34, the knocking level is set to the reference level KN (0
) or more, the retard MTR (NC+
2) is corrected to the retard side by a predetermined amount ΔTR in the next step 36.

This embodiment shows a case where the first cylinder 1a and the fourth cylinder 1d are made into one group, and the second cylinder lb and the third cylinder 1c are made into another group, as cylinder groups with almost equal intake conditions. Ori.

As is clear from Table 1 above, 9, for example, the first cylinder [retard angle J
iTR('0))I A's non-king is specified and the bell KN
(0) or more, the retard amount TR(2) of the fourth cylinder 1d corresponding to NC+2, that is, NO-2 is also corrected, and the non-king of the second cylinder (retard amount TR(1)) is set to a predetermined level KN. (0) or more, NC+2 or NO-
The retardation amount TR(3) of the second cylinder lb corresponding to 2 is also corrected. Incidentally, in step 36, when NC+2>3.

It is executed by replacing NC+2 with NC-2, and between the first cylinder 1a and the fourth cylinder 1d, and the second cylinder l.
The correction of the retard amount is reflected between the cylinder b and the third cylinder IC.

When the above retardation amount rewriting processing is completed, in the first step 35, the ignition timing TI of the next cylinder to be ignited following the cylinder in which non-king has been detected is calculated. In other words, if the retard amount TR(NC) is corrected first, then the retard amount TR(NC+1
) is read out, this retard amount is added to the basic ignition timing TI determined in the main routine, and the added value is set as the ignition timing TI of the next cylinder.

The ignition timing T'I calculated in this way is written to the timer I[18 in the secondary step 37, and energization is started.
When TI elapses after the start of energization, the drive circuit 19 is activated and the high ft pressure of the ignition coil 5 is transferred to the distributor 6.
The signal is then applied to the corresponding spark plug to cause ignition.

In this embodiment, a cylinder discriminating means for identifying a cylinder in an explosion stroke; Although a case has been shown in which part of the configuration of the ignition timing control device, such as the second ignition timing correction means and the knocking level determination means, is configured by software, it goes without saying that these may be configured by hardware.

Furthermore, the number of cylinders is not limited to the four-cylinder engine 2 as described above, but can also be applied to other multi-cylinder engines. In this case, 9, for example, in a 6-cylinder engine.

1st. It is preferable to group the cylinder into the sixth cylinder and the second to fourth cylinders, and in the case of a three-cylinder engine,
1st. It is preferable to group them into a third cylinder and a second cylinder.

C Effects of the Invention As described above, according to the ignition timing control device for a multi-cylinder engine according to the present invention, not only the ignition timing is corrected for each cylinder in which non-king detection is performed by the first ignition timing correction means; Since the second ignition timing correction means can reflect the ignition timing correction in advance to other cylinders in the same group whose intake conditions are almost the same as that cylinder, it is possible to predict the occurrence of non-king among all cylinders. The ignition timing can be corrected to the retarded side by selecting in advance the cylinder that will be used. Therefore, it is possible to avoid delays in correction as a whole, and it is also possible to prevent wasteful correction even for cylinders that do not require correction of one ignition timing, thereby extremely efficiently preventing the occurrence of knocking. There are possible advantages.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention. FIG. 2 is a detailed block diagram of the constituent parts of the controller, FIG. 3 is a waveform diagram of each part, and FIGS. 4 to 6 are flowcharts showing the calculation processing of the MPU. 3 is a controller, 7 is an air flow sensor. 9 is a vibration sensor, 10 is an MPU, 12 is a waveform shaping circuit,
13 is a knock detection circuit, and 15 is a timer I. 16 is ROM, 17 is RAM, 18 is tie? I[. It is. Figure 3 Figure 6

Claims (1)

[Claims] 1. A knocking detection means for detecting knocking, a cylinder discrimination means for discriminating a cylinder in an explosion stroke, and correcting the ignition timing of the cylinder corresponding to the output from the output of the knocking detection means and the output of the cylinder discrimination means. a first ignition timing correction means; a non-king level determining means for receiving the output of the knocking detecting means and comparing the knocking level with a predetermined level; A second ignition timing correction means for correcting the ignition timing of other cylinders in the group to which the cylinder in which knocking has occurred belongs, which are grouped into groups of cylinders having substantially the same condition. Ignition timing control device for multi-cylinder engines.