JPS5915676A - Ignition-timing controller for internal combustion engine - Google Patents

Abstract

PURPOSE:To permit engine operation in the vicinity of MBT (Minimum advance for best torque) in idling by detecting ignition and miss-fire of the engine from the crank angle position where the number of revolution of engine becomes max. and advancing the ignition timing when ignition is realized and delaying the ignition timing when miss-fire is generated. CONSTITUTION:A throttle-valve switch is read-out in step 51, and steps 53-57 are executed only in idling. The crank angle RPMDEG with which the acceleration speed in engine revolution in the preceding ignition cycle becomes max. is compared with, for example, 70 deg. (step 53). When RPMDEG is larger than 70 deg., ignition is judged, and the ignition timing is advanced. When RPMDEG is equal to or less than 70 deg. miss-fire is judged, and the ignition timing is delayed. Thus, the ignition timing can be set always in the vicinity of MBT in idling.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to an ignition timing control device during idling of an internal combustion engine.

(Prior Art) Examples of conventional ignition timing control devices for internal combustion engines include the following.

It is checked whether the internal combustion engine is in idle-link operation, and when the engine is in idle-link operation, the ignition timing, that is, the ignition advance value A I) is determined based on the engine rotational speed N (rpm) according to the characteristics shown in FIG. Determine V(0Bi'Dc).

In addition, when not in idle-link operation, according to the characteristics shown in Fig. 2, engine rotation speed N and intake air flow rate Q (or suction negative pressure, or engine rotation speed N and intake air flow rate Q and constant K to T, = KQ Determine the basic ignition advance value AI)V based on the basic fuel injection amount Tp) calculated as /N,
This is corrected according to the cooling water temperature Tw and whether or not cranking (starting) is in progress to determine the ignition advance value ADV.

Furthermore, according to the magnitude of the battery voltage, the ignition coil's energization time is determined by taking into account the time it takes for the ignition coil's primary current to reach a predetermined value. The time to start energization is determined. In addition, the energization angle can be determined from the engine rotation speed N and the energization time, and the ignition cycle angle of the engine (1 for a 4-cylinder engine)
The de-energized angle DWELL is determined by subtracting the energized angle from the 800.6-cylinder engine (1200). In other words, regarding the rotation angle of the engine, the energization start time D W E L
The supply of primary current to the ignition coil starts at L, h, the ignition timing rotated by the conduction angle, that is, the ignition advance angle Al) V (01(11)C) , - The mixture of fuel and air is ignited.

As shown in FIG. 1, especially when the engine speed N is approximately 100 rpm or less during idling, the ignition advance values A, J
) V is almost constant and is usually set around 20013T DC.

In general, the ignition advance value A J) V and the engine generated torque (
kg...) The relationship is as shown in Figure 3, and the ignition advance value A
[) When V is 30 to 40 (013TDC), the generated torque is maximum, and such ignition advance value A, I) V
Set to 30~/1σ so that the engine outputs maximum torque? 1ill Ill, M 13T
(Minimum dvancc for Best T
orque) lIJ*, 1. l, mame embroidery advance angle value 3f)
~40011TJ)C is called the M131' point.

Furthermore, the ignition advance value A[)V and the fuel consumption rate (g/I)s
-h) In other words, the relationship with fuel consumption is as shown in Figure 4, and as is clear from comparing Figures 3 and 4, when the ignition advance value ADV is near the M131' point , M 13
In the T control state, fuel efficiency is minimized. Therefore, the ignition advance value A1) V l 30~40' 13TJ)C
It is preferable to set near (7) M 13 T point K G .

However, as shown in Fig. 1, especially when the engine speed N is about 1000 rpm or less during idling, the ignition advance value is almost constant and is set close to about 20'J3TDC (=J.The reason for this is When idling, the intake air flow rate is small, so the effective compression ratio is small. Therefore, if the ignition timing is set to AL13'F, aK, misfires may occur due to individual engine differences and conditions such as intake air temperature and humidity. This is because the stability of engine rotation is easily impaired, and 200HT
This is because if ignition is performed near DC, the cylinder pressure has increased to some extent, and even under such conditions, reliable and stable ignition performance cannot be obtained.

Therefore, with conventional equipment, idling operation is used to prevent misfires.
The problem was that fuel efficiency was sacrificed in order to obtain stable ignition performance.

(Purpose of the Invention) This invention was made by focusing on such conventional problems, and it is possible to prevent misfires and ensure stable ignition performance, exhaust performance, and rotational stability when the engine is idling. The purpose is to perform feedback control to keep the ignition timing close to MI3T to improve engine output and fuel efficiency.

(Structure and operation of the invention) Therefore, the features of the present invention are to set the ignition timing during idling near the MrJT point, and to set the ignition timing at the engine rotation speed N
Depending on the size of the crank angular position θ(dN/dt)max at which the engine rotational acceleration dN/dt obtained from
By adding 1,11 to the number of ignitions or misfires, increasing the ignition advance value if ignition occurs, and decreasing the ignition advance value if misfire occurs, the ignition timing can be adjusted to MBT while preventing misfires. This is feedback control as shown in the figure.

Hereinafter, embodiments will be described based on the drawings, taking a four-cylinder engine as an example.

FIG. 5 shows the configuration of an ignition timing control device according to the present invention. In the figure, reference numeral 1 is a crank angle sensor built into the distributor 2;
290°, 470°, 650°, . . ., the reference RI' indicating 70° before the compression top dead center of each cylinder;
It emits the F signal and 10PO8 signals for every 1° of crank angle.

Among the standard REF signals, the reference REF multiplied signal corresponding to 700BTDC of a specific cylinder (usually cylinder 1), and the reference 1 (EF multiplied signal of other cylinders) have a large pulse width, and the cylinders are discriminated based on this. 3 is a cylinder pressure sensor consisting of a piezoelectric element configured with a spark plug 40 and a washer, which generates a cylinder pressure P signal.

5 is an air flow meter that emits an intake air flow rate Q signal.
Ru. Reference numeral 6 denotes a throttle valve switch, which indicates whether the throttle valve 7 is closed (in other words, when idling) or open (when not idling).
Emit a signal. 8 is a neutral switch, which indicates whether the gear position of tranosminosis 9 is in neutral or not 1
-Nietraral N E [J 71' Signal is emitted.

10 is bayateri, 11 is ignition switch, 12
When the ignition switch 11 is turned on and the control unit relay 11 is turned on, a battery power signal V11, which also serves as the main power source for the battery 10, is issued via the control unit relay 12. Also, when the ignition switch 11 star] terminal is connected, the star terminal
-1 Stark S l' A ]t, T signal is generated through the motor relay 1;3 to indicate that cranking is in progress. Numeral 14 is a water temperature sensor which issues a signal indicating the engine cooling water temperature.

Each of these signals is input to the control unit 15.
111, the calculation is processed and the ignition timing control LGN OgeI
A signal is output and this ignition timing control IQN OUT
The power transistor 16 is driven by the signal Y, and the primary current of the ignition coil 17 is turned on and off, thereby controlling the ignition timing of the engine.

FIG. 6 shows the configuration of the control unit 15-4-
o In the figure, the control unit 15 includes a signal shaping circuit 18, an input interface circuit 151, and a CPU 2.
0, memory 21, calculation timer circuit 22, output interface circuit 23, backup circuit 2/1, switching circuit 5,
It is composed of a drive circuit 26, a power supply circuit 27, and others.

The memory 21 also includes a memory 29, a mask ROM 30, a PR, and an OM31.

FIG. 7 is a block diagram showing the internal structure of the main part of the IC of the input/output interface arithmetic timer circuit including the input interface circuit 1, the arithmetic timer circuit 22, and the output interface circuit 23 shown in FIG. In the same figure, 32 is a multiplexer which outputs an analog cylinder pressure P signal,
The intake air flow report Q signal, battery voltage VB signal, and cooling water temperature signal 1 are input, and one of them is selected and output. ; U3 is the AIJ conversion circuit, multiplexer 3
Convert the analog signal selected in 2 to a digital signal 1
-ru. 34 is a digital input/output circuit, which inputs digital signals (idling month) LE double signal neutral NI UT signal, starter S 'J' AltT signal.
-ru. :35 is the rotation angle counter circuit, crank angle 1
Standard 1st every 800) is reset by the I-pa signal,
1°L) It has an angle timer that is non-assigned by the O8 signal and an ANGLE register, and generates an angle coincidence interrupt signal S synchronized with the rotation angle. And this A,
N ('+LE) By reading the E register, the crank angular position θ can be detected.

3G is a rotational speed measurement circuit that counts the number of 1°I) O8 signals during a predetermined measurement time, stores the count value in the R, P M registers at the end of the measurement time, and records the rotational speed. A measurement end interrupt signal S2 is generated. This method 1) By reading the M register, the engine rotation speed N (rpm) can be read. This reading is performed immediately after receiving the rotational speed measurement end interrupt signal S2.

Note that the above-mentioned measurement time, that is, the measurement period, is normally set to the QmSeC prerecording, taking into account the resolution at low rotations and the counter overflow at high rotations.

At this open period of 10 m5ec, 600 rr
) In idle link, 10 times per revolution of the engine.
The rotational speed opening side will be performed once.

37 is an interrupt control circuit which receives the rotation angle counter circuit, the angle coincidence interrupt signal S from 35, the rotation speed measurement circuit, the rotation speed measurement end interrupt signal S2 from 6, and various other interrupts for control. and issues an interrupt request to CPU 2f).

3s is the LGN pulse circuit, AJ) ■ register, I) W
l(;LL register has two counters and a comparator, and emits an ignition timing control IGNO[J'l' pulse signal.

A I) V register contains CP (operated with J20)
In addition, the ignition advance value A I) V is temporarily stored, and the DWEJ
,, the transistor has a non-conducting angle IJW 1 calculated by the CPU 20! ]L ]· value is temporarily stored. Ignition timing control 1. [, iN OL river pulse is standard H,E
One counter is l'PO8 from the time the l'' signal is input.
Count the signals, A.1. ) When the value of the V register and the count value match, it becomes 0", and from when it reaches ll0I+, another counter counts the 1°POS signal, and when the value of the DWELL register and the count value match, it becomes "1". The two counters are reference n, g F signal and ignition timing control L <-; N 0U71' signal is ll0
It is cleared when it becomes I+, and this operation is repeated 1-0
Therefore, when the ignition timing control IGNOUT signal is "1pa", the primary current of the ignition coil 170 is energized, and when it becomes ``0'', the primary current is cut off and the ignition spark flies, and the primary current only changes by the non-energizing angle. becomes de-energized.

Next, the operation will be explained.

The relationship between cylinder pressure P and crank angle position θ is shown as 1-P-θ
The waveform, the N-θ waveform showing the relationship between the engine rotational speed N and the crank angular position θ, and the engine rotational acceleration (IN / rJ t
The relationship between the dN/dt-θ waveform and the crank angular position θ is shown in FIG. 8(a) (l]Hc). As is clear from the figure, combustion takes place in the cylinder and effective torque is generated.
Then, due to the inertia of the engine, the engine rotational speed N becomes slightly slower and begins to rise, and continues to rise until the end of the combustion stroke, after which the engine rotational speed N begins to fall due to the effect of compression in the next cylinder. Then, a little later than the next combustion, the ``Nisho'' starts again, and the cycle repeats.

The engine rotational acceleration is dN/dt, and the engine rotational speed N
It is found by differentiating .

The crank angle position θ(d
Between N/dt)may and the ignition advance value ADV, there is a 9th
It has already been confirmed that there is a relationship as shown in the figure.

Based on the value of θ(dN/dt)max, it can be determined whether the engine has ignited or misfired. When the engine ignites, θ(dN/dt)max is located after top dead center, and when it misfires, the engine rotation speed N since the previous ignition
After decreasing monotonically (showing an almost constant value of -1),
θ(dN/dt)max is located before the second dead center.

This invention focuses on this point, and determines whether ignition has occurred or misfired based on the magnitude of θ(dN/dt)max, and also sets the ignition advance value ADV to the M B l' point in advance,
In the case of ignition, the ignition advance value ADV is increased (advanced) by a predetermined angle α, and in the case of misfire, it is decreased (advanced) by a predetermined angle β.
By feeding back the ignition advance value so as to retard the ignition timing, an ignition timing control system with excellent fuel efficiency, exhaust performance, and rotational stability under all conditions during idling is realized.

That is, the reference IMO EF signal from the crank angle sensor 1 (Fig. 10(a) and 1°l), the OS signal (Fig. 10(a))
From 1))), the crank angle position θ is determined by the rotation angle counter circuit 35K. In addition, as described above, the number of 1° P OS signals is determined by the rotational speed measurement circuit 36 for each measurement cycle (that is, every approximately Qmsec) having a preset measurement interval (Fig. 10 (C)). (frequency) is counted (Fig. 10(d)), and the engine rotation speed i
N asks. Then, by finding the difference (FIG. 10(e)) over the measurement interval of the engine rotational speed N, the engine rotational acceleration dN/dt can be obtained.

In addition, in FIG. 10, (fl is the crank angle position, (
gl is the rotation angle counter circuit 35.
The value of the register is the engine rotational speed N in the same measurement interval as (d) when one car's engine misfires, and as shown in the figure, it has decreased almost monotonically since the previous ignition, and ( The engine rotational acceleration at the time of a misfire (I
It shows N/di, and has shown a nearly constant (@ value (or O) since the previous ignition.

The feedback control of the ignition timing according to the present invention is executed at 700 degrees before the top dead center of each cylinder by the reference i(,E L" signal) every 180 degrees by the angle coincidence interrupt signal S from the rotation angle counter circuit 35. will be started.

First, by using the rotational variation open side program shown in FIG. 11, the crank angle position 0 (dN
/dt)max is found. That is, at the beginning of the program, the crank angle position θ at the end of rotation speed measurement, which is stored in the ANGLIS register of the rotation angle counter circuit 35, is loaded into the general-purpose register AK (step 41 in FIG. 11). Next, R and P of the rotational speed measuring circuit 36
Load the engine rotational speed N within the measurement interval stored in the M register into the general-purpose register B (step 42);
The difference between the values of R and PMOLD representing the engine rotational speed N in the previous measurement section assigned to a predetermined location in the RAM 280 is calculated (step 43), and this difference is stored in the RAM 28.
I(l)MDI representing the past maximum difference within the same cycle of ignition timing control assigned to a predetermined location of
It is compared with the value of 'I' (step 44). As a result of the comparison,
If the current difference is larger than the past maximum difference, store the current difference in 1(,PMl,)LT (Step 45)
At the same time, set the current crank angle position θ to 1 (P1\November) in the specified location of RAM 28 (Step 11G). than the difference/]Sake Jl, do nothing ℃・.Next ℃・te, 1(, P 4. Set the value of register Z, that is, the value of the current engine rotational speed N, to general register 13 ■ 2) − de(7 (Step/I7), and then set the values of register 1) to H, PM(
month) 1) (step 48), and the process ends in preparation for the next processing. R, PMI) LT's difference 1-Nawa C, ((IN / (It) max value and 11,
Since the value of θ (dN/dL) max of i is cleared at the end of each cycle of the ignition timing noise back control program described below, therefore, such a Through the process, the crank f6 position θ(dN/di)max at which the engine rotational acceleration within one cycle (one ignition period) of ignition timing control is maximized is determined.

Next item, 3j, figure 12 [z, +, knee 4-70f ya 1-
ici>ttsu-c, ignition 11. A program will be executed for one period of time. Rabbit, O in Figure 12
First, the engine determines whether it is an idle link or not by turning the valve switch 6 (and 2, -1-Ralsu switch 82 and clutch switch (not shown) at 6). satr,ru (step 51).

Next, the engine rotation speed is set to a predetermined value (for example, Hl(1(l
rpm ) or less (step 5).
2).

This is because, as described above, the measurement cycle of the engine rotational speed N in the present invention is 10 m5ec g degrees, so the control 1111 is limited to a range where rotational fluctuations can be sufficiently measured. If the engine is not in the idle link state, or if the engine rotational speed N is equal to or higher than a predetermined value even in the idle link state, conventional ignition timing control is performed.

If the engine rotation speed is idling and the engine rotation speed is low (current N is less than a predetermined value), the engine rotation speed is measured using the above-mentioned rotation fluctuation measurement program. H, PMI CC representing the position θ(dN/d+,) may: Compare with wo70' (step 5
;3).

This value of 700 represents the top dead center; in other words, the rotation angle counter circuit 35 is reset by the reference H, DI signal that is generated every 700 seconds before the top dead center, and then the rotation angle counter circuit 35 is reset by the reference H, D I. Since the rotation angle is increased by the rotation angle counter circuit: A, N of 35 at the top dead center.
, i l·[゛] This is because the value of the register indicates 1-'zO.

If θ(dN/dt)max is 70, it is determined that ignition has occurred, and the correction value of the ignition advance angle of I(,, A +M predetermined value jl) is added to step 5.・1), θ
(dN/dj,)max <"', it is determined that there is a misfire, and the correction value A I)V
Step 55).

1141 rotational fluctuation measurement program (Fig. 11) at ℃
Now the open side is 1 +, in a cycle of 1ijl ( dI'J
/ di ) max to ILL' November,
Clear the value of T and the value of No. 41JJ G to +(,1) indicating θ (dN/dt) max (step 56.57)
.

Next, in step 58), the basic value TA[)V of the ignition advance calculated in advance according to the engine speed NVC shown in FIG. 1 is loaded into the general-purpose register A. Value A, 1) Vi'13K wo7Jl Ete, find the ignition advance angle (ii AJ)V (step 59), and further find the energization start angle 'lI'DW corresponding to the basic value 'l'AI)V
Step 60: Load EL and L into the general-purpose register 13.
), also add the correction value AJ, )VJpaB1〈,
Energization start angle 1. ) WjCL ■ Imprison J (step (i
f) Set the values of general-purpose registers A and B to 'lI'.
AJJV.

TI)~A/E L L (step 62.6
3) Prepare for the next cycle.

Basics of ignition advance angle 1 shift TAIJV ii approx. 2001+TI
) C", tlti + JE value AI) V FBK is about 10 to 20°I3']" D C, and the ignition advance value A1. ,)■Ha approx. 30~4 (10B
'l'D('') If the ignition occurs, increase the ignition angle by α and move the ignition timing toward the MBT point to improve the ignition and fuel efficiency, and prevent misfires. In this case, reduce the ignition advance value by β (retard) to prevent misfire, stabilize rotation, and improve exhaust performance.3 In this case, β is made larger than α to prevent misfire. In this case, ensure ignition next time.α and β are, for example, about β−3α, and specifically, it is preferable to set α==J0.β−:3°.In this way, The ignition advance value AI)V is feedback-controlled so that it is always near the MBT point during idling.

The above-mentioned ignition advance value AJ, )V and energization start angle 1)\■1
=; According to L I, from the ION pulse circuit 38,
An ignition M1' timing control IGN 0tJT signal is output, which is 1'' at the energization start timing and 0 at the ignition timing.

(Effects of the Invention) As explained above, according to the present invention, A7. For example, the cycle is determined by the magnitude of the crank angular position θ (dN/dt)max at which the engine rotational acceleration obtained from the engine rotational speed within one ignition cycle of the engine during idling operation is maximum. It is determined whether there is gradual ignition or misfire, and if ignition occurs, the next ignition advance value is advanced, and if misfire is caused, it is delayed, and feedback is applied so that the ignition timing is near M 13 T. Since the configuration is set to 5, the engine is M 13 'I' when idling.
Therefore, the effect of realizing idle link operation that is superior in output, fuel efficiency, rotational stability, etc. can be obtained.

According to experiments conducted by the present inventor, under the conditions of the same intake air flow and the same air-fuel ratio, a remarkable effect was obtained in which the engine rotation speed during idle link was approximately 50 to 100 rpm. .

[Brief explanation of the drawing]

Figure 1 is a diagram with percentages of ignition advance value during idle link in a conventional ignition timing control system for an internal combustion engine, and Figure 2 is a diagram with 11f of the same.
Figure 3 is a characteristic diagram showing the general relationship between the ignition advance value and generated torque, and Figure 4 is a characteristic diagram showing the general relationship between the ignition advance value and the fuel consumption rate. A characteristic diagram showing the relationship, FIG. 5 is a block diagram of the ignition timing control device for an internal combustion engine according to the present invention, FIG. 6 is a block diagram of the control unit I shown in FIG. 5, and FIG. 7 is a block diagram of the control unit I shown in FIG. A configuration diagram showing the main parts of the output interface calculation timer circuit. Figure 8 is a waveform diagram of cylinder pressure, engine rotation speed, and engine rotation acceleration.
Fig. 9 is a characteristic diagram showing the relationship between the ignition advance value and θ (dN/dt) max, Fig. 10 is a time chart of the main signals of the device of the present invention, and Fig. 11 is the operation of the rotational fluctuation measurement program. FIG. 12 is a flowchart explaining the operation of the ignition timing feedback control program. ■・・・Crank angle sensor, 2°゛・・・Distributor, 4°・°“・Spark plug, 6・・・Throttle valve switch, ]0
...Battery, 15...Control unit 1ゝ, 16...Power transistor, 1
7...Ignition coil, 19...Input interface circuit, 20...ct' (J, 2
1. Memory, 22... Arithmetic timer circuit, 2; 3... Output interface circuit, 28...
...RAM, :32...Multiplexer, 33
・・・・・・A 1. ) Conversion circuit; 3/I...
Digital input/output circuit: 35...Rotation angle j variation counter circuit; 36...Rotation speed measurement circuit; 37...Interrupt control circuit; 38...IU
N pulse circuit, ■・)1゛...Reference signal,
POS...1° signal, IJ) LD... Idling word/Vll...Battery voltage signal, 1, (iN O[-] 'I"... ...Ignition timing control signal, N...Engine rotation speed tw, AD
V...Ignition advance angle value, θ...Crank angle position, Special Applicant Nissan Motor Co., Ltd. Patent Attorney Sato Megumi Yamamoto - Earth/[D Act 2 figure! 3 ward, ignition line angle ('arrrc) Act 4 Figure ignition line 'l j'li Avv to8rDc) Bō7
Diagram a mouth clan 7 angle @: 1 θ 9 diagram, valve, enter*mii,! Aov carvc) L/7
Floor of mouth 12 diagram

Claims (1)

[Claims] Means for detecting whether or not the engine is in an idle link state, means for detecting the crank angular position θ, means for measuring the engine rotational speed N at every predetermined period, and every ignition synchronization training period. Crank angle position θ (dN
/dt)max, and the θ(dN/dt)
Based on the magnitude of max, it is determined whether the engine has ignited or misfired, and the ignition advance value is set so that when ignition occurs, the ignition advance value ADV is advanced, and when a misfire occurs, the ignition advance value ADV is retarded. An ignition timing control device for an internal combustion engine which performs feedbank control so that the ignition timing during idle link is near the point KAHE=1131', comprising means for calculating and outputting a value ADV.