JPS59201975A - Ignition timing control device in internal-combustion engine - Google Patents

Abstract

PURPOSE:To enhance the output and as well fuel consumption performances of an engine, by providing such an arrangement that a crank angle at which the internal pressure of a cylinder is maximum is obtained, an actual ignition timing is obtained by searching a map which is beforehand stored in a memory means, in accordance with the thus obtained crank angle, and the ignition timing is controlled in dependence upon whether the firing is made at a first ignition or not. CONSTITUTION:An angle detecting means 3 detects a crank angle at which the internal pressure of a cylinder is maximum, in accordance with the outputs of a crank angle sensor 1 and a cylinder pressure sensor 2. Further, in accordance with the output of the angle detecting means 3 and as well the output of a memory means 4 that stores therein the relation between the crank angle at which the internal pressure of the cylinder is maximum and the firing timing, an actual firing timing is determined by a firing judging means 5. When the firing is normally made at a first ignition, an ignition timing estimating means 6 estimates the ignition timing to set the ignition timing at a predetermined position. On the contrary, when the firing is missed at the first ignition, the ignition timing estimating means 6 estimates the ignition timing to retard the latter. Then, in accordance with the estimated ignition timing, an ignition device 8 is controlled by means of an ignition timing control means 7.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Application of the Invention) The present invention relates to a spark timing control device for an internal combustion engine, and more particularly to ignition timing detection and ignition timing feedback control technology.

(Prior art) As a conventional ignition timing control technology, for example, 2 patent applications
-74866, JP-A-57-191530, etc.

Furthermore, as prior art to the present invention, the present applicant has disclosed the patent application filed in Japanese Patent Application No. 57-
No. 122200, Japanese Patent Application No. 129008/1986, etc. have been filed.

The prior art described in 2 above detects a misfire from fluctuations in the rotational speed or rotational acceleration of the engine, immediately re-ignites if a misfire occurs, and further controls the ignition timing by feedback to adjust the ignition advance angle to MET (minimum 5parka-). dva
, nce for beSt torque) to improve exhaust purification performance, fuel efficiency, and 5-revolution stability performance.

However, in the prior art described in '2, the sensitivity of rotational speed or rotational acceleration to the ignition timing is essentially not very good, so it is difficult to determine at what number of ignitions the second ignition has occurred, and therefore it is difficult to determine the exact number of ignitions. There was a problem in that ignition timing control could not be performed and sufficient control performance could not be obtained.

(LJ aspect of the invention) The present invention has been made to solve the above problem, and aims to provide an ignition timing control device that can accurately determine the ignition timing and perform optimal feedback control. purpose.

(Summary of the invention) In order to achieve the above object, the present invention has the following features.

The crank angle at which the cylinder pressure is maximized is determined from the outputs of the sensor that detects the cylinder pressure and the crank angle. Memorize the relationship, find the actual ignition timing from the detected crank angle, and calculate the first ignition timing based on the value of that and the first lit point of 1!J! Determine whether the ignition has been interrupted or not, and adjust the ignition timing to MBT based on the result.
It is configured to provide feedback control.

FIG. 1 is a diagram showing the overall configuration of the present invention.

In FIG. 1, ■ is a crank angle sensor that detects the crank angle between the holes, and 2 is a pressure sensor that detects the cylinder pressure.

Further, the angle detecting means 3 detects the crank angle at which the cylinder pressure becomes maximum based on the signals from both of the sensors.

Furthermore, the storage means 4 stores in advance the relationship between the crank angle at which the cylinder pressure becomes maximum and the ignition timing (see FIG. 7, which will be described later).

Next, the ignition determination means 5 determines the actual ignition timing from the stored value in the storage means 4 and the value determined by the angle detection means 3, and determines the first ignition timing based on the correspondence with the first ignition timing at that time. 0 In other words, if the actual ignition timing matches the first ignition timing, it means that the ignition occurred in the first ignition, and if they do not match, the ignition occurs in the first ignition. The second and subsequent ignitions are considered to have ignited the flame.

The ignition method may be one in which ignition is always performed multiple times at every - ignition timing, or a method in which misfire is detected and re-ignition is performed only when a misfire occurs (for example, Japanese Patent Application No. 57-77
536) is also acceptable.

Next, the ignition timing calculation means 6 calculates the angle detection means 3. The next ignition timing is calculated according to the signals from the storage means 4 and the ignition determination means 5.

How to calculate the above ignition timing? ] Nasaru.

For example, if the ignition occurs normally on the first ignition, the 7 ignition timing should be set to MBT, that is, the crank angle that produces the maximum pressure should be set at a predetermined position after top dead center (for example, 12° ATDC).
) Calculate the ignition timing so that

In addition, if ignition does not occur on the first ignition, the ignition timing is delayed by 7 seconds.

Specifically, the basic ignition timing value (special deviation in Figure 11 below) is calculated according to the operating condition at that time (for example, rotational speed and load), and the feedback coefficient for setting the ignition timing to MBi'' is calculated. Then, the actual ignition timing value is calculated by adding that value to the basic ignition timing value.

Next, the ignition timing control means 7 sends out an ignition signal at a time point corresponding to the ignition timing 4 (fi) calculated by the above-mentioned ignition timing τ9 determining means 6, and thereby operates the ignition device 8 to perform ignition.

(Example) FIG. 2 is a diagram showing an embodiment of the present invention.

In FIG. 2, the crank angle sensor I outputs a unit angle signal S, (for example, S in FIG. 5) every time the crankshaft rotates by a predetermined unit angle (1° or 2'), Standard angle (180° for 4-cylinder engines, 120' for 6-cylinder engines)
) Every time the rotation is made, the reference angle signal S2 (for example, Fig. 5 82) is generated.
Output.

The pressure sensor 2 outputs a pressure signal S3 corresponding to the cylinder pressure.For example, as shown in FIG. I: IE? It is possible to use the IL element 20 for /Tl.

Microcomputer 9 is MPU], 0. R.A.
M]], ROM +2, input/output device 113, and the like. Then, each of the above-mentioned signals 81 to S3 is inputted, predetermined calculations are performed, and an ignition signal S4 is output.

The ignition device 8 includes a transistor 15. Distributor] 62 spark plugs 17A to 171i', 182 point large carp /
l/]ri, etc.

When the ignition signal S4 is applied (becomes low level), the transistor 15 is turned off, so that a high voltage is generated in the secondary winding of the ignition coil (l≦).

The voltage is applied to the spark plug (any one of 17A to 17F) in the order of ignition through the power distributor 16, and a spark discharge is generated in the gap between the large spark plugs and ignition is performed. .

Next, the operation of the microcomputer 9 will be explained, but before explaining the overall operation, the free run counter provided in the input/output device 13 will be explained first.

FIG. 4 is a block diagram of an example of a free run counter.

In FIG. 4, the edge detector 50 receives a manually inputted pulse signal S. Detects the rising edge of , detects the rising edge of
Output.

A 16-bit free-running counter 51.

It is incremented by KJ every time a predetermined clock pulse (for example, a 16 μs clock) is counted.

If the expression overflows, the overflow detector 52 outputs a timer overflow interrupt signal S12, and at the same time it is reset to the initial value (ie, $0000).

The input capture register 53 holds the value of the free running counter 5J at the time when the detection signal S11 of the edge detector 50 is input manually.

In addition, the above detection signal “I+” is sent to the MASK register 54.
If the EICI bit is ``■'', the input capture signal ``+8'' is sent to the MPU (10 in Figure 2) via the intertool bus 55, and the input capture signal is Generates a capture interrupt.

Here the pulse signal S, which is powered by 7 people. Finally, use the funeral position S1 shown in Figure 2. 1, the negative signal S1 is 2. For example, as shown at 81 in FIG. 5, two cycles are 2 degrees in crank angle and the duty is 50%.

Since Zunawaji 1° is a high level and 1° is a low level signal, the input capture interrupt described above is generated every 2° of crank angle, and the input capture at this time is
By reading the value of the capture register 53, the MPU 10 can read the value of the free running counter 51 when the unit angle signal S1 is input manually.

Therefore, by finding the difference between the previous value of the free running counter 51 and the current value, the unit angle signal S1
It is possible to detect the period of

In the present invention, the above-mentioned tortoise angle 13. Perform the treatment described below on Sl at month ■ (1), and reduce the internal pressure of 15 <J■
Find the crank angle θm that is the maximum (1/j I)m.
/ The relationship between cylinder pressure and ignition timing is
11 planes are completed.

FIG. 6 is a general cylinder pressure waveform diagram, and the crank angle θm at which the zero cylinder pressure reaches the maximum value Pm is determined.

The force that is closely related to the engine's maximum torque and fuel efficiency is
ll is a predetermined value determined by the characteristics of the engine (A'l'DC
10" to 20 degrees), the most efficient pz luck 11 (< can be achieved.The ignition timing at this time is M
It is Bi.

Furthermore, there is a nearly linear relationship between 0m and ignition time 1 (JJ) as shown in Figure 7, and 0m can be changed by changing the ignition timing.

Therefore, 0m is always the desired value.

Optimal operation can be achieved by controlling the ignition timing and changing the ignition timing.

Note that the characteristics shown in FIG. 7 have an air-fuel ratio of stoichiometric air-fuel J, t (buttocks).

-14, 8).
It is known that the tendency is almost the same over a wide range of about 2 to 20.

Also, from the characteristics shown in Figure 7, if θm is determined, it is possible to calculate the brightness at two ignition times0.Then, the ratio of the first ignition timing at that time and the above 7r' to the fire one waiting time is calculated. Accordingly, it is possible to determine whether or not ignition occurred during the first ignition.

The present invention has been made based on the above phenomenon.

Next, detection of θI11 will be explained.

The reference angle signal S2 in FIG. 2 is set to be generated at 70' before the top dead center (TDC) of each cylinder, for example, as shown in FIG. 582.

In addition, a predetermined value between 1 and 60 (corresponding to 2° to 12σ) is stored in the angle register in the input/output device 13 in Fig. 2, and the reference angle signal S2 is manually input. By counting the number of angle signals S1 as the number of words.

When the crank angle reaches a crank angle corresponding to the value written in the angle register (O is the generation point of the reference angle signal S2), the angle-gender information is sent to MPU10.

If the value of the side light angle register is set to 34 (corresponding to 58 degrees), the angle-to-gender combination will be performed at 2 degrees before top dead center (BTDC2'').

FIG. 8 is a flowchart of the program including the angle and gender described above.

In this interrupt routine, as shown in FIG.

The mask of EXTIRQZ, that is, the free-run counter timer word measurement interrupt (hereinafter referred to as input capture interrupt) is released.

Specifically, the 1st RQZ bit (EICI bit) of the MASK register 54 in FIG.
/ Make it.

Also clear AGLCNT (Memo 1.!OSCAM location) for pressure signal processing described below.

As mentioned above, this angle including gender is ETDC2°
Therefore, by canceling the input capture interrupt (ENABJ, E) in the interrupt routine shown in FIG. 8, the input capture interrupt will occur when the secondary unit angle signal sI is input manually.

Every time the unit angle signal S1 is input, that is, the crank angle f
1. , an input capture interrupt occurs.

Therefore, the input capture interrupt occurs when the value of the angle register reaches 35 (equivalent to 70').

It first occurs at TDC, and thereafter at crank angle 2°f.
! It occurs at j.

In this input capture interrupt, the θm and feedback coefficient calculation program shown in FIG. 9 is executed.

The following explanation will be given based on FIG. 9, but first, the data names in FIG. 9 will be explained.

AGLCNT is a memory used as a vignetting count allocated to RAM and SCA a, and is cleared with the angle and gender described above, and is incremented every time an input/capture interrupt occurs.

PIMAX is assigned to the SCB address of the RAM, and stores the maximum value of the converted cylinder pressure A1].

'I'lTPMX U: , It is allocated to the sca address of RAM, and A and GL in the case of PIRuX above.
The value of CN'l'', that is, the angle in z units starting from T1)C is memorized.

TLIPMX +I ~ THPMX +6 is the 6 consecutive THPMXO values, that is, the TI of the gold cylinder (in this case, 6 cylinders)
M17)! l1CI), SCE.

SCE, $FO, $F1. , $F2 address.''

ADVFBK is assigned to addresses $1-3 of RAM and increases the 1 point major advance angle by +1. This is the data area in which feedback control is performed so that either O or -1 is changed and becomes NET.

Next, FIG. 9 will be explained.

First, J)1 determines whether AGLCN'l' is 0 or not.

When AGLCNT = O, the crank angle is 11D.
This shows the case where cK is reached and an input capture interrupt is entered for the first time. Therefore, in this case, after clearing 137l)] mAX of the subsequent processing, P
8 hate.

When AGLCNT # is O, A and J of pressure signal s8 have already been input capture interrupts [)q times.
) Since the conversion has started (P1o described later), go to P2, read the AD value (value converted from analog to digital) of the pressure signal s3 that has already been completed, and set that value as A.

3) Compare your A with PIMAX, the maximum value so far.

l) If A≧PIMA, X, ie the new value is not less than the previous maximum, go to P4 and store A as the new IMAX.

Also, with Pl and P6, the value of AGLCNT is TI-
After storing to IPMX, go to IN.

f) If A is smaller than PIMAX at 8, immediately go to P8.

Next, in 1) 8, AGLCNT is incremented by 1.

Next, if 1) (details will be explained later) is NO, go to Plo.

After starting AD conversion of the IE force signal S8, immediately proceed to "End".

By repeating the above process, PIMAX always has
The AD value of the maximum value of the cylinder pressure up to now is stored, and THPMX contains the AGLCN value at the time when the maximum value was reached.
The value of T, that is, the crank angle at 2° intervals starting from TDC is stored.

Note that the completion of AD conversion is not specifically checked here, but the reason for this is that the engine rotation speed is 60° when the crank angle is 2°.
Even at 00 rpm, it corresponds to about 57 Its, AD
The conversion speed is approximately 30μ with a general successive approximation type AD converter.
s and outside, the two programs are configured to always read the AD conversion value at the next interrupt, A, I)
This eliminates the waiting time during conversion.

Next, in P9, it is determined whether AGLCNT is 26 or not.

AGLCNT is 26, which means the crank angle is A, TI.
) C5 (corresponds to 1'), but at this point, the combustion of the air-fuel mixture in the cylinder has almost finished. By this point, the cylinder pressure must have reached R Daibutsu. Become.

Therefore, l) the value of I'MAX at this point and '
The value of I゛HPMX indicates the maximum value J)m of the cylinder pressure in one combustion cycle and the crank angle θm at that time.

If P9 is YES, ie, AGLCNT' = 26, go to Pll.

After masking EXTIRQZ in P1□, go to P1□.

At Pl2, THPMX +1 to THPMX +6
After softening 1 byte at a time, THPMX + 1
~THPMX + 6K store.

By doing this, THPMX + I~T
HPMX-4-6 always holds the latest six values of θm.

In other words, θm of the gold cylinder of a 6-cylinder engine is TI-TPMX
+1 to 'l'llPMX+6.

, then calculate the feedback coefficient ADVF13K for the next ignition using p, 3-1) 2o.

As shown in the characteristics of Fig. 7, in the case of the engine of this example, 9 When the ignition timing is BTDC 20°, θm is approximately ATDC 18.
°, 13TDC: Approximately ATDC at 30°! 12
°. Therefore, the values of i'HI)MX correspond to 9 and 6, respectively.

1) As stated in 1j < , TI (PMX + 1 ~ TH
PMX + 6 is the total value of θ1n of the cylinder to be ignited the second time because the value of θm of the segment is stored in the temporal order.
is stored in THPMX + 6.

Therefore, first in P18, the value of THPMX + 6 is read and this value is set as A.

Next, P, 4, is a part in which it is determined whether or not ignition occurred during the first ignition.

In other words, the first ignition timing is set to, for example, J31”DC25°.
When set to , as can be seen from the characteristics in Figure 7.

If ignition occurs at the first ignition, θ+n is A'rD
It should be C14°.

ATDC14@ corresponds to 7 in THPMX.

Therefore, if P14 and A are 8 or more, it can be determined that the ignition did not occur during the first ignition.

In addition, the value used as the standard for comparison on page 14 (8) is 2.
Varies depending on ignition timing value. That is, assuming that ignition occurred in the first ignition, θm may be determined from θm using the characteristics shown in FIG. 7, and 7+1 may be used as the reference value.

In this example, if A is 8 or more in P14, the ignition did not occur during the first ignition.In such a case, the ignition timing needs to be delayed overall, so go to P15 and set the feedback coefficient ADVFBK. Let be - engineering.

■) If 14 and A is less than 8, 1 at the first ignition.
1: This is the case where it is always enlarged, and in that case, 216 ~
and determine the size of A and 6.

In general, there is a close correlation between θm and maximum torque (best fuel efficiency), and it differs depending on the two engines, but generally θm is A'I'I
) It is known that maximum torque (and hence good fuel efficiency) is generated when a specific value within the range of C10' to 20' is generated.

In the case of this example, it is assumed that the maximum torque θm, that is, MBT θm, is, for example, ATDC 12°.

A, T1) CI2° corresponds to 6 in THPMX, so in the case of two engines, the ignition timing should be controlled so that THPM, X is always 6.

Therefore, if P+6 is 6, this indicates that the previous high point timing was appropriate, so go to P18 and set the feedback coefficient ADVFI3K to O.

If A<6 at P+6, this indicates that the 2nd ignition timing is too advanced than the appropriate value, so the process goes to P17, where the feedback coefficient ADVFBK is set to -1, and the 7th ignition timing is controlled to be delayed.

If A>6 at P+6, this indicates that the 8 ignition timing is delayed from the appropriate value, so go to JP+9, set the feedback coefficient ADVFBK to +1, and control to advance the 5 ignition timing.

Next, at P2o, after shifting the values of 6 ADVI"Bl (for 6 cylinders) by 1 byte, AI)VJi"Bl
< +l ~ADVFI (store in K+6.

By doing this, ADVFBK + 1~A
In DVF, BK+6, the values of six feedback coefficients are held while being circulated sequentially according to the ignition order of each '1Cff7J (for example, 5th, 6th, 2nd, 4th cylinder). It turns out.

Therefore, it always indicates the value held in ADVFBK +6 or the feedback coefficient of the next ignition.

Therefore, the value of ADV]i″BK + 6 is read out as the feed bank coefficient ADVFBK.

Next, FIG. 10 is a flowchart 1 for calculating two ignition timings.

In Fig. 10, first, at P2, the basic ignition timing value ■ is determined from the engine rotational speed N and load measurement. Calculate.

This procedure is similar to conventional ignition timing control; for example, ignition timing values (advanced angle values) corresponding to the rotational speed and load amount as shown in Fig. 11 are stored in memory in advance as a data table. , a method is used in which a value corresponding to the rotational speed and load ht at that time is read out.

Note that as the load hi:, intake air amount, intake negative pressure, fuel injection pulse +4JTp (calculated from intake air amount and rotational speed), etc. can be used.

In addition, the basic ignition timing value ■. In addition to the calculation method described above, there is also a method of calculating only from two rotational speeds or only from suction negative pressure. There is also a method in which control is performed using different characteristics when the throttle valve is fully closed (idling) and at other times.

Next, at I) 2°, the feedback coefficient ADVFBK is added to the basic ignition timing value (■) to calculate the actual ignition timing value IR.

Next, in step 1] 23, the above-mentioned ignition timing control is output, and ignition timing control is performed according to the output value.

The ignition timing control method is the same as before.

For example, if the reference angle signal S2 is generated at B'I'l)C70°, store the values of u, 70 - rice in a register,
The configuration is shifted so that the ignition signal S4 is output when the integrated value of the signal S1 for single 0" f, which is manually input after the reference angle signal S2 is input, matches the above value (-Δ- in the case of a 2° signal). Good.

(Effects of the Invention) As explained above, in the present invention, the crank angle at which the cylinder internal pressure is maximum is determined from the outputs of the sensor that detects the air pressure and the sensor that detects the crank angle. The relationship between the crank angle at which the internal pressure is maximum and the ignition timing is memorized in advance, and the actual ignition timing is determined from that relationship and the detected crank angle, and that value and the first ignition timing at that time are calculated.
Based on the correspondence with the ignition timing of -1, it is determined whether the ignition was ignited or not at the first ignition, and based on the result, feedback control is performed to set the ignition timing to MET. Therefore, the ignition timing can be determined accurately. Therefore, since the ignition timing can be precisely controlled, output performance and fuel efficiency can be improved.

For example, according to experiments, the fuel consumption when idling is 5 to 18
% could be reduced.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the overall configuration of the present invention, FIG. 2 is a diagram of an embodiment of the present invention, FIG. 3 is a diagram of an example of a pressure sensor, and FIG. 4 is a block diagram of an example of a free run counter. Figure 5 is an example of the output waveform of the crank angle sensor, Figure 6 is a characteristic diagram of cylinder pressure, Figure 7 is a relationship diagram with ignition timing θm, and Figure 8 is a diagram of the program executed with angle-spreading. 9 is a flowchart of θm and feedback coefficient calculation, and FIG. 10 is a flowchart of ignition timing calculation. FIG. 11 is an example of the characteristics of the basic ignition timing value. Explanation of symbols] Crank angle sensor 2 Pressure sensor 3 Angle detection means 4 Memory means 5 Ignition determination means 6 Ignition timing calculation means 7 Ignition timing control Means 8... Ignition device agent Junnosuke Nakamura 11 Figure JP2 Figure ■ L -J
1P3 figure Ijp5 figure'r-2°-: j=-+20°□: T'DC

Claims (1)

[Scope of Claims] An ignition timing control device having a function of performing multiple ignitions every 11 ignition strokes or multiple times of ignition when a misfire is detected. A means for detecting the crank angle of the engine, a means for detecting the cylinder pressure, an angle detection memory value for detecting the crank angle at which the cylinder pressure is maximum from the signals of both of the above means, and a value obtained by the above angle detecting means. ignition determining means for determining the actual ignition timing from the above and determining whether or not the first ignition ignited from the correspondence between the value and the first ignition timing at that time, and the angle detection 11-) ignition timing calculation means for calculating ignition timing so that the crank angle at which the cylinder pressure is maximum is at a predetermined position after top dead center, based on signals from the storage means and the ignition determination means; and ignition timing control means for controlling ignition timing according to a calculation result of the means. 2. The ignition timing calculation means calculates a feedback coefficient based on the signals of the angle detection means, storage means, and ignition determination means, and calculates a basic ignition timing stored in advance as a value corresponding to the operating variables of the engine. 2. The illumination device according to claim 1, wherein the IUJ at the time of ignition is calculated by reading out the value and adding the feedback coefficient to that value.