JPH02169875A - Ignition timing control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To correctly suppress the error of the ignition timing caused by the angular acceleration by correcting the ignition timing at the time of acceleration based on the difference value between the time measured value between the preset angles at this time and the previous time and the time measured value between the preset angles at the previous time and the time before the previous time, the ignition spark advance value, and the angular acceleration correction coefficient. CONSTITUTION:An arithmetic means 200 calculates the engine rotating speed based on the reference position pulse in response to the number of cylinders for every preset crank angle generated by a crank angle detecting means 100, and a determining means 500 determines the angular acceleration correction coefficient. The arithmetic means 300 determines the difference value between the time measured value between the preset angles at this time and the previous time and the time measure value between the preset angles at the previous time and the time before the previous time. An ignition timing correcting means 600 calculates the determined difference value, angular speed correction value, and the ignition spark advance value calculated by a calculating means 400 and calculates the ignition timing at the time of acceleration. The drift of the ignition timing caused by the angular acceleration is correctly suppressed, and the optimum ignition timing control at the time of acceleration can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an ignition timing control device for electronically controlling the ignition timing of an internal combustion engine.

BACKGROUND OF THE INVENTION Various types of electronic ignition timing control devices have been provided in the past.
Some of these are described in Japanese Patent No. 193768 and the like. This is configured so that the ignition timing correction time corresponding to angular acceleration is zero at the boundary of the acceleration/deceleration dead zone, and outside the dead zone, the correction time changes continuously according to the angular acceleration with this zero as the base point. This is designed to suppress variations in the ignition advance angle that occur when the rotational speed is unstable, such as during idling, and to correct the ignition timing in accordance with the angular acceleration.

Problem to be Solved by the Invention By the way, as a control method for correcting the ignition timing error caused by the angular acceleration of the rank axis as described above, a correction coefficient is obtained by linear interpolation and extrapolation of the period described below, and this Predetermined advance angle control is performed based on the correction coefficient. In other words, the time required for the crank angle sensor to rotate between the reference position pulses generated is measured and stored, and the previous value T is stored.

The difference value Td between the current value T1 and the current value T1 is calculated, and the next cycle is predicted and the correction coefficient is calculated only from the difference value, so high accuracy during acceleration is achieved over a wide range from low speed to high speed Ignition timing control was difficult.

To describe a specific example in detail, first, FIGS. 13 to 15 show the relationship between the target ignition timing during dry cooking and the actual ignition timing. That is, if there is no angular acceleration correction, the actual ignition timing (broken line) will be significantly retarded from the target ignition timing (solid line) during a series of accelerations, as shown in FIG.

On the other hand, if the angular acceleration is corrected using the method described above, and the correction coefficient is selected so that the target ignition timing and the actual ignition timing match on the low rotation side, the Although the accuracy is improved, as shown in FIG. 14, as the engine speed increases, the actual ignition timing (broken line) retards the target ignition timing (solid line).

On the other hand, if the correction coefficient is selected so that the target ignition timing and the actual ignition timing match on the high speed side, as shown in Fig. (dashed line) is advanced. When the correction coefficient is a constant value as described above, it is difficult to perform highly accurate ignition timing during acceleration.

Means and Function for Solving the Problems The present invention was devised in view of the above-mentioned conventional problems, and as shown in FIG. 1, a reference position pulse is generated according to the number of cylinders at a predetermined crank angle. a crank angle detecting means 100 that measures the ON and OFF pulse widths of the reference position pulse to calculate the engine rotation speed; means 300 for calculating the difference value between the measured value and the time measured value between the previous and previous predetermined angles; means 400 for calculating the ignition advance value in accordance with the engine operating state; and angular acceleration as a function of the engine speed. Means 500 for determining a correction coefficient; Means 600 for correcting the ignition timing during acceleration; the difference between the time measurement values, the ignition advance value, and the angular acceleration correction coefficient;
It is characterized by having the following. In this way, since the ignition timing correction coefficient is determined as a function of the engine speed, it is possible to accurately suppress errors in ignition timing caused by angular acceleration.

Example Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 3 shows the mechanical configuration of a 4-cycle, 4-cylinder, electronically controlled internal combustion engine l to which the present invention is applied, and 2 indicates a CPU 3. ROM4. A microcomputer equipped with a RAM 5°110 board 6, this microcomputer 2 is equipped with an air flow meter 8 provided in an intake pipe 7.
The intake air amount signal Qa from the throttle valve 9, the opening amount signal TVO from the opening detection sensor 10 of the throttle valve 9, and the water temperature sensor 1.
In addition to the cooling water temperature signal T from 1, O provided in the exhaust pipe 12, the reference voltage V from the sensor 13, and the photoelectric crank angle sensor 21 built into the distributor 14.
The current engine operating state is detected by inputting the engine speed signal N, etc. from the engine, and the ignition timing is controlled and the signal is output to the spark plug 15, while the injected fuel amount is controlled and the signal is output to the spark plug 15. It is output to the fuel injection valve 16.

The crank angle sensor 21 is connected to a rotor plate 2 connected to the disshaft 17 as shown in FIG.
2, a light emitting diode and a light receiving diode (not shown) installed above and below the rotor plate 22, and a signal processing section.
, #2. #3. Four signal slits 23, 24, 25, 26 corresponding to the #4 cylinder and one cylinder discrimination reference signal slit 27 are provided on the same circumference.

The four signal slits 23, 24.25° 26 are set to have the same length in the circumferential direction, and are arranged at symmetrical positions with respect to the disshaft 17, that is, at equal intervals of 180°. In addition, each signal slit 23,
24.25.26 is the ON signal (HL/Bell Po) at crank angle 180″ which is the reference position pulse signal for each cylinder.
As shown in Fig. 3a, the compression top dead center (TDC) of the crank rotation angle is 1. Rising from around 75 degrees, TD
The width from the H level edge to the L level edge is set so that it falls at about 5 degrees before C.

On the other hand, the length of the cylinder discrimination reference signal slit 27 in the circumferential direction is set shorter than the length of each signal slit 23, 24, 25° 26, and the #1 cylinder signal slit 23
H
The level edge (OH) is set at approximately 5° after TDC.

And each of the above slits 23, 24.25, 26.27
As shown in FIG. 2A, an ON-OFF pulse signal consisting of an H level signal PH with a rank angle of 180° and a cylinder discrimination reference signal P8 is outputted by the light passing through the cylinder. and,
The microcomputer 2 that manually inputs each of these pulse signals measures the time between the crank angle 180' signals to detect the engine rotation speed N, and the engine rotation speed N, the intake air amount signal Qa from the air flow meter 8, and the water temperature sensor. Variable ignition timing control is performed using ignition timing value data that is obtained as a function of the cooling water temperature Tw from 11 and stored in advance (see Figure 3C), and the ignition timing value data is used during idling and deceleration. Fixed ignition timing control is performed according to the engine speed N that is not used (see Figure 3).

Incidentally, the above crank angle is 180@H level p of the pulse signal,
(.

N) Width is 70″, L level P, (OFF) width is 110°
The energization time in the fixed ignition timing control is the same as the H level pulse width at the crank angle of 180°, and the ignition timing is the same as the L level edge. The time is determined by calculating the energization time stored in the microcomputer 2 into the energization angle, and the ignition timing is set to an advance timing of a predetermined angle based on the H level PM of the 180° crank angle signal. In this variable ignition timing control, an error in ignition timing caused by angular acceleration during vehicle acceleration is also controlled by a predetermined means, which will be described later.

The microcomputer 2 also performs fuel injection control depending on the engine operating state, for example, at the initial stage of startup, performs simultaneous injection in all cylinders based on the crank angle position detection signal, while under predetermined conditions, the crank angle position detection signal So-called sequential injection is performed in which the fuel is injected in order before the compression top dead center of each cylinder based on the cylinder discrimination signal P.

Hereinafter, the control action of the microcomputer 2 will be explained based on the flowchart shown in FIG.

This basic routine is interrupted at the rising or falling edge of the reference position pulse (H level pH...) output from the crank angle sensor 21. First, in section 1, read the time between each pulse (Fig. 3 aDT, -DTn),
In Section 2, the time ratio (DDT) is calculated as D T , , / D
It is determined by the formula of Tn. Next, in section 3, after turning on the start switch, it is determined whether the input pulse is equal to or greater than a predetermined number of times. Here, if NOl, that is, if the crankshaft rotates less than two times and generates less than five pulses, as at the beginning of startup, the process proceeds to section 4 because cylinder discrimination is not performed. Here, fuel injection is performed once every two times of the H level signal, and ignition is
Control flag (FL
G) and proceed to the routine described later (FLGA=0).

On the other hand, if YES in section 3 above, section 5
It is determined whether the 180° pulse signal is at H level or not, and if it is not at H level, the process proceeds to the next routine by interrupting with a rising edge. If it is determined in section 5 that the signal is at the H level, the process proceeds to section 6, where it is determined whether the time ratio calculated in section 2 is greater than or equal to a predetermined value. That is, here, the current L level angle θ of the 180° pulse signal. It is determined whether the ratio 00N10oFF (see FIG. 3) between FF and the previous H level angle θ is greater than 3, for example. The reason why "3 or more" is selected here is to set the value within a range where pulse width resolution can be achieved and a fixed advance angle range (5° to 10°) of the ignition timing can be obtained. Here, if it is determined to be 3 or more (if the cylinder discrimination reference signal is OH once every five times), the cylinder recognition signal FLGB is set to 1 in section 7, and the cylinder is simply recognized. Next, in section 8, the engine rotational speed N during a measurement period of 180° angle, which will be described later, is calculated. Next, in section 9, it is determined whether or not the starting switch is OFF, and if it is OFF, in section 10, the engine speed N is set to 400 rpm, for example.
It is determined whether or not it is equal to or greater than 400 r"p"m, and if it is equal to or greater than 400 r"p"m, it is determined in section 11 whether FLGC is set to 1 or not. In other words, here, it is determined whether all conditions such as the starting switch and engine speed satisfy the conditions for sequential control, and if YES, section 1
At step 2, a flag for performing sequential injection 2-ignition advance is set, and the process moves to a routine (FLGA=2) to be described later.

On the other hand, if any one of the above sections 9, 10. The routine described below (FLGA
=1).

On the other hand, if the determination is No in section 6 (other than the case where the cylinder determination reference signal is OH), then in section 14
It is determined whether LGB is set to 1, that is, whether or not the cylinder recognition signal is set. If YES, the M cylinder (CYL) is set to 0 in section 15 to set a reference. Here, MCYL means 0. 1. 2. 3 is used as a variable, and when it is 0, it is the first cylinder, and when it is 2, it is the second cylinder. When FLGB=1, MCYL is set to 0. Next, in section 16, FLG
C is set to 1, and in section 17, the time T1° for 180° is used as an element for determining the engine speed N as described above. is measured by 'EDT.

That is, here, since MCYL=0 in section 15, the four times of DT, +DT, +DT, and +DT6 are added and measured. Next, in section 18, the current and previous H levels P, 1, which are the standards for ignition timing, are explained.
That is, the time DT between the L level angle (110°) and the interval θ.
In this case, since there is a cylinder discrimination reference signal P8, "EDT," which includes this signal Ps.
Measured by. That is, D T 3+ D T ,
+DTS is measured by adding up the three times.

Subsequently, in section 19, as shown in FIG. 3a, the time DTB between 110° θ8 is sequentially updated, and a new reference value is measured and stored. This is used to calculate the angular acceleration component described later, and becomes a control element for each acceleration correction ignition timing control added to the variable ignition timing control (FIG. 3C). Next, in section 20, set FLGB to 0
Make it.

In other words, when FLGB is O, the cylinder discrimination reference signal P is not set, and at this time MCYL=Q in section 15, so next time it will be 0+1 for the first cylinder, then for the second cylinder. It is recognized as a cylinder, and the process moves to section 8, whereupon the determination and processing described above are performed.

If 1 is not set in FLGB in the section 14, the cylinder identification signal P8 is not outputted, so the process of adding MCYL one cylinder at a time is performed in the section 21, and the next section is performed. Then section 2
3, measure the time DTB of 110°θ1 from DTfi,
The process moves to the above-mentioned section 19 to perform subsequent processing.

Hereinafter, the above FLGA=O, FLGA=1. FLGA=
The second routine will be explained. First, the routine for FLGA=O from section 4 where cylinder identification is not possible is as follows.
Section 730teTt[l 80°
It is determined whether the pulse signal includes the I level cylinder discrimination reference signal Ps, and if YES, the ignition primary coil is energized at about 75 degrees before compression top dead center in section 31, and the previous Pulse I] Determine whether or not fuel injection has been performed based on the level Pl+ signal, and select YE.
If it is S, it returns without any processing.

If the answer is No in Section 32, Section 3
3 performs simultaneous injection in all cylinders. That is, in this section 33, simultaneous injection is performed in all cylinders at a rate of once every two times of the H level signal, so three simultaneous injections are performed in two revolutions of the crankshaft. Therefore, starting performance is improved and engine rotation can be stabilized. Further, in the section 30, the 180'' pulse signal is at L level Pt.

If it is determined that this is the case, section 34 cuts off the current to the ignition primary coil. That is, it ignites at about 5 degrees before compression top dead center and returns. Note that in a state where such cylinder discrimination is not performed, the cylinder discrimination reference signal is ignited at the time of the cylinder discrimination reference signal in addition to the above-mentioned crank angle position signal, but the cylinder discrimination reference signal is generated at 5 degrees after the compression top dead center, and the combustion stroke Since the ignition occurs immediately after, there is no adverse effect on the combustion action of the engine, and on the contrary, a good combustion action can be obtained.

Next, in the routine <FLGΔ-1 following section 13, cylinder identification has already been performed and the engine is under operating conditions such as starting, so the control is as shown in FIG. 7.

First, in section 40 it is determined whether or not the 180° pulse signal is at H level PH, and if it is at H level PI+, in section 41 it is determined whether or not the time ratio is greater than a predetermined value, that is, greater than "3". If it is determined that it is 3 or more, a cylinder identification flag is set in section 42 and the process returns directly. Also, if it is determined No in section 40, that is, the L level, the process proceeds to section 43, where it is determined whether or not the cylinder identification flag is set. If it is set, the process returns, but if it is not set, In section 44, the current to the ignition primary coil is cut off and ignition is started based on the fixed ignition timing control. On the other hand, if the time ratio is determined to be "3" or less in the section 41, that is, the 180
When the level P11 of the pulse signal is reached, the primary coil is energized in section 45, and then in section 46 it is determined whether or not the injection was performed at the previous level P1. If YES here, proceed to section 48 and NO
If so, in section 47 simultaneous injection is performed in all cylinders twice per crankshaft revolution, and the process proceeds to section 48. In this section 48, processing is performed to lower the cylinder identification flag, and the process returns directly.

Next, in the routine continued from section 12 <FLGA=2, as shown in FIG. 8, in section 50 it is determined whether the 180° pulse signal is at the H level P, and if it is No, the routine returns directly. If YES, section 51
It is determined whether the time ratio is "3" or more. YES here
If so, clear the signal, but if no, section 5
At step 2, ignition and energization are performed by variable ignition timing control in each cylinder corresponding to MCYL based on sequential control, fuel injection is performed for each cylinder, and the process returns as is.

Next, the ignition timing correction control for the angular acceleration described above will be explained based on the flowchart of FIG. That is, first, in section 60, the engine speed N, basic injection m''rP+engine cooling water temperature T1 and throttle opening amount T■O are read, and then in section 61, the above-mentioned N is read.

A predetermined ignition advance value (θADv) is determined from TDC using the above-mentioned ignition timing value data obtained from the function of T, ,T. In section 62, as shown in FIG. 3, the current pulse time D T Bn for 110° θ1 is read, and then in section 63 it is determined whether the opening degree 1TVo of throttle valve 9 is greater than a predetermined value. If YES here, that is, if it is determined that the opening amount is greater than the idle rotation, the previous pulse time DTBn□ between 110'01 is read in section 64, and the process proceeds to section 65. In this section 65, the angular acceleration correction coefficient K is read from a table map obtained in advance from a function of the engine speed N shown in FIG. Next, in section 66, the ignition energization time t. is calculated using the formula. Here, θ is the T of #2CYL which is the 3H level edge of the subsequent ON pulse signal.
It is a 75° angle to DC. Then, in section 67, a timer is set so that the spark plug 15 ignites after the energization time (t□as) corrected as described above.

On the other hand, if it is determined in the section 63 that the throttle opening degree m (TVO) is less than the idle rotation, the energization time is determined in the section 68 using the following formula. That is, when the engine speed is below the idle speed, the correction coefficient K is set to zero to perform no ignition timing correction based on angular acceleration, and the energization time is set based on the above-described fixed ignition timing control.

Here, the meaning of the angular acceleration correction coefficient and its setting method will be explained based on FIGS. 11A-D and FIG. 12.

That is, it is obvious that when the rotational speed of the engine is constant, there is no need to perform angular acceleration correction, and the larger the variation in rotational speed is, the more accurate correction is required. Therefore, if we consider as an example the case where the throttle valve 9 is fully opened and sudden acceleration is performed, where the variation in rotational speed is maximum, first of all, the torque generated by the engine when the throttle valve 9 is fully opened is Therefore, the angular acceleration θ of the engine is substantially constant as shown in FIG. 11C. As a result, the engine rotational speed θ, which is the first-order integral of the angular acceleration O, becomes a linear function as shown in FIG. 11B, and the engine rotational position θ, which is the second-order integral of the angular acceleration θ, becomes a linear function as shown in FIG. 11A. It becomes a quadratic function.

Here, since it was found that θ is a quadratic function of time t, 1. General formula % Formula % Also, when considering the subsequent state change with θ-O0 as a reference, the formula (2) becomes 0='4 at' + bt...■゛. 01+f) for every predetermined crank angle θd (for example, 180°)
,.

A crank angle reference signal is generated at θ3, and its time is t, .
If t,,tn..., 'J aLi + bt+ (7d =O...■''
−a at2 + btt−2”θd = O・=■ given at20 bto−3・0d−0...■.

From the formula ■, find (,, from the formula ■, 1., and the difference 1,,
-1. , that is, the time from time t until the next crank angle reference signal is generated is tn l, -FT1]
Kaju subordinate E seal possible 1. ,■On the other hand, if we apply the above correction formula χ to the above formula, ,Ly-(tz t,)+K[
(t, t+) (t, to) l-・■, substitute L+ and Lx obtained from formulas ■ and ■ to the right-hand side of formula ■, and calculate K by setting the right-hand side of formula ■ - the right-hand side of formula ■. Now, if we consider the physical meaning of equation (2), a is the angular acceleration, which is approximately constant, and b is the engine rotation speed, which changes from moment to moment. θd is a predetermined value. Therefore, when K is determined by substituting a, b, and θd, it is determined as shown by the solid line in FIG. 12. When the engine rotation speed is low, the value is smaller than when the engine rotation speed is high, and the correction coefficient is a function that depends on the rotation speed.

In this way, by predetermining K and storing it in the table map shown in FIG. 12, the equation
Alternatively, the ignition timing can be corrected with high accuracy in a short period of time from low speed rotation to high speed rotation of the engine using the formula χ.

As shown in FIG. 12, the table map shows the engine output based on the throttle valve opening or fuel injection amount, or the engagement of the clutch.

It goes without saying that different values may be selected depending on the equivalent moment due to cutting.

In this manner, in this embodiment, the correction coefficient K is determined from a function of the engine speed N, so that errors in ignition timing caused by angular acceleration can be appropriately suppressed. In addition, crank angle sensor 2
One rotor plate 22 has signal slits 23 to 26 corresponding to the number of cylinders and one cylinder discrimination reference signal slit 2.
Since rotor plate 22 and 7 are arranged on the same circumference, rotor plate 22
The structure can be simplified. Furthermore, cylinder discrimination reference signal pickpocket.

27 is formed within 30' after compression top dead center, even if the cylinder is ignited based on the cylinder discrimination signal in addition to the crank angle position signal, even if cylinder discrimination is impossible such as at the beginning of startup, the compression top dead center will always be detected. It will be ignited before and immediately after dead center. Therefore, a situation where the fuel is ignited during the suction stroke is reliably avoided.

Note that the present invention is not limited to four-cylinder engines.

Effects of the Invention As is clear from the above explanation, according to the ignition timing control device for an internal combustion engine according to the present invention, in particular, each time between the current and previous reference position pulses, and between the previous and the previous reference position pulses generated from the crank angle detection means. The ignition timing during acceleration is corrected by calculating the difference between the measured values, the ignition advance value calculated according to the engine operating state, and the angular acceleration correction coefficient calculated as a function of the engine speed. Therefore, errors in ignition timing caused by angular acceleration can be appropriately suppressed, and optimal ignition timing control during acceleration can be obtained.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a diagram corresponding to the claims of the ignition timing control device according to the present invention, Fig. 2 is an enlarged view of the main parts of a crank angle sensor used in an embodiment of the present invention, and Fig. 3 is FIG. 4 is an overall configuration diagram showing the control elements of the internal combustion engine to which this embodiment is applied. FIG. 5 is a flowchart showing the basic control of this embodiment. FIG. F shown in Figure 5
The flowchart of LGA=O, FIG. 7 is the flowchart of FLGA=1 shown in FIG. 5, and FIG. 8 is the flowchart of FLGA=1 shown in FIG.
FIG. 9 is a flowchart of FLGA=2 shown in the figure, FIG. 9 is a flowchart of ignition timing correction control of this embodiment, and FIG.
The figure shows a table map used for this ignition timing correction control.
FIGS. 11A to 11D are characteristic diagrams explaining the meaning of angular acceleration,
Fig. 12 is a table map shown in Fig. 10 in which different values are stored depending on the throttle valve opening and the equivalent moment of inertia due to clutch disengagement, Fig. 13 is a characteristic diagram showing the ignition timing of a conventional example without angular acceleration correction, FIGS. 14 and 15 are characteristic diagrams when angular acceleration correction is performed by linear interpolation and extrapolation. 100... Crank angle detection means, 200... Engine rotation speed calculation means, 300... Difference value calculation means, 400...
- Ignition advance angle value calculation means, 500... Angular acceleration correction value determination means, 600... Ignition timing correction means. Figure 1 Figure 2 Figure 9 Figure 12 Time Figure 13 Time Figure 14 Time Figure 15

Claims (1)

[Claims] (1) crank angle detection means for generating a reference position pulse for each cylinder at a predetermined crank angle; and means for calculating the engine rotational speed by measuring the duration of each ON and OFF pulse of the reference position pulse; Above ON pulse or OFF
means for calculating the difference value between the time measurement value between the current and previous predetermined angles and the time measurement value between the previous and the two previous predetermined angles using a pulse, and means for calculating an ignition advance value according to the engine operating state; The apparatus further comprises means for determining an angular acceleration correction coefficient as a function of the engine speed, and means for correcting the ignition timing during acceleration from the difference value of the time measurement value, the ignition advance value, and the angular acceleration correction coefficient. Characteristics of the ignition timing control device for internal combustion engines.