JPH01142267A - Control device for ignition timing - Google Patents

Abstract

PURPOSE:To properly carry out an ignition timing control in an ignition timing control signal which includes a first timing and a second timing which is later than the first timing in one period and which commands the ignition timing of a cylinder corresponding to a second period in the second period, by setting each timing to the optimum. CONSTITUTION:An ignition timing control device 1 receives various detected signals from a sensor group 3 for detecting various operating conditions of an engine while, on the other hand, outputs an ignition timing control signal which includes a first timing and a second timing which is later than the first timing in one period and which commands the ignition timing of a cylinder corresponding to a second timing in the second timing, to an igniter 5. In this case, a means for obtaining the optimum ignition timing to determine the second timing for each cylinder is provided on the ignition timing control device 1. Also, a means for operating the period of the determined second timing is provided. Further, a means for determining the first timing in accordance with the period of the next ignition timing is provided. Thereby, an ignition energy can be controlled to be the maximum in accordance with an operating condition.

Description

[Detailed description of the invention] [Industrial application field]

The present invention provides ignition timing control in which the energization time of the ignition coil of each cylinder in an internal combustion engine is set to a constant value regardless of a certain operating state, or conversely controlled to an optimum value depending on a certain operating state. Regarding equipment.

[Prior art]

゛Conventionally, electronically controlled ignition systems detect engine operating conditions such as engine speed, engine load, engine coolant temperature, and knocking, and detect the top dead center habit of each cylinder detected by a crank angle sensor. A device that has an ignition timing control device that determines the advance angle for the number and instructs the igniter to determine the optimum ignition timing from the advance angle, and an igniter that controls the energization timing of the ignition coil and controls the energization and cutoff of the ignition coil. It has been known. The ignition timing control signal output from the ignition timing control device to the igniter is the first timing (hereinafter, ``timing'' is ``timing'').
(used in the sense of ``timing'') and a second period that is delayed by a time corresponding to a constant rotation angle of the engine from the first period and commands the ignition timing of the spark plug of each cylinder. Usually, the first period is given by the rising edge of the pulse and the second period is given by the falling edge of the pulse, or vice versa. The igniter to which the ignition timing control signal is input determines the timing of energizing the ignition coil according to the time interval between the first period and the second period, that is, the pulse width of the ignition timing control signal. That is, as shown in FIG. 9(a), the ignition timing control signal is given in the form of a pulse waveform with a constant duty ratio.
．． t22. The falling edge of the pulse waveform, such as t32, is the second timing, and indicates the optimum ignition timing for the first to third cylinders, etc. Also, the first period preceding the second period is t
ll, t21. It is given at the rising edge of the pulse waveform such as t31. The ignition cycles of the first to third cylinders, such as T, T, and T3, are also shown. The igniter that inputs such an ignition timing control signal is
The ignition timing control signal is integrated with respect to time to generate an integral signal shown in FIGS. That is, the integral signal is transmitted from the first time tll of the first ignition cycle T to the second time t12 of the period T.
At d+, it increases linearly in the positive direction from the initial value 0,
Subsequently, the value decreases linearly from the value at the second time t12 until the first time t21 in the next second ignition cycle T2. Then, the igniter detects a time tlo, t20 when the above-mentioned integral signal that linearly decreases becomes lower than a predetermined threshold value Eth.
．． t30 etc. is the time to start energizing the ignition coil, and the second time t12. t22. An ignition control signal having a pulse waveform shown in FIG. 9(C) with the ignition coil cut-off timing at t32 or the like is output to the control terminal of the power transistor that controls the ignition coil. As a result, the current flowing through the ignition coil, which is energized and cut off by the power transistor, has the waveform shown in FIG. t22. It is ignited at t32 etc. Incidentally, the ignition timing t12. The energization start timing t20. in the next ignition cycle from t22 etc. Time 02 until t30 etc.
03 depends on the pulse width Td+ of the ignition timing control signal in the previous ignition cycle and the slope of the straight line of the integral signal. Now, if the slope of the increasing straight line of the integral signal is a1 and the slope of the decreasing straight line is b, then D*=(a-Td +-Bth)/b
−・(1) Mouth a=(a −Td2−Eth)/
b - (2
). Also, the ignition timing control signal has a duty ratio r = Td+/T+=Td*/Tz =Tds/Ts
"-" (3) is assumed to be constant. Therefore, the energization time 'llx, Ws is 112=T
2-T+ ・r-a/b+[! th/b
-(4) Ws=Ts-Ti + r-a/b+Bt
h/b - (5), and if the advance angle of each cylinder is equal and the engine speed is constant without fluctuation, each ignition period is equal T + = T z = T a = Tc
``''(6), so the duty ratio is r=b/a...
...If you set it to (7), L=! ! th/b・
・-(8) Wa=[! th/b
...(9), and it becomes possible to keep the energization time of the ignition coil constant regardless of the engine speed. In this way, by keeping the energization time constant regardless of the rotational speed of the engine, optimal ignition and prevention of heating of the ignition coil are achieved. Furthermore, it is well known that such an integral signal can be generated using an integral circuit, and controlling the timing of starting energization of the ignition coil using this integral signal is disclosed in Japanese Patent Laid-Open No. 50-83.
This method is known from Japanese Patent Application Laid-open No. 643, Japanese Patent Application Laid-Open No. 55-23394, and the like.

[Problems to be solved by the invention]

However, in reality, the advance angle of each cylinder differs for each cylinder when knocking prevention control is performed, so the above-mentioned ignition period is not constant, and Equation (6) does not hold. Also, when the engine speed changes rapidly,
The same thing can be said. Therefore, if the duty ratio of the ignition timing control signal is constant as in the past, the energization time will not be constant during knock prevention control or when the engine speed is changing significantly. That is, as shown in FIG. 8, when the duty ratio r is constant,
Ignition period T1. 2. If the 73rd etc. are different, the energization time W,
, W2. W, the shade is not constant but changes irregularly, and the timing of starting energization is hunting. This has caused deterioration in ignition performance and heating of the ignition coil. Also, the energization time of the ignition coil determines the ignition energy of the ignition plug, but the optimal ignition energy of the ignition plug varies depending on the operating conditions such as the engine temperature, the mixture ratio of fuel and air, and the advance angle. . For this reason, if the duty ratio of the ignition timing control signal is kept constant as in the past, it is possible to keep the energization time constant regardless of the rotation speed in a steady rotation state, but the above-mentioned changes in engine temperature, fuel and air, etc. Since it is not possible to variably control the constant energization time to an optimal value that does not depend on the engine speed depending on certain operating conditions such as mixture ratio and advance angle, it is not possible to obtain the optimum ignition energy according to the operating condition. The problem was that it was not possible. The present invention was made to solve the above problems, and its purpose is to control the energization time of the ignition coil so as to obtain the optimum ignition energy.

[Means to solve the problem]

The structure of the invention to solve the above problems is that there is a first period in one cycle and the! An ignition timing control signal that includes a second period delayed from the first period and instructs the ignition timing of the cylinder corresponding to the period at the second period, according to the time difference between the first period and the second period, In an ignition timing control device that outputs an output to an igniter that controls the energization timing of the ignition coil in the next ignition cycle, an ignition timing determining means that determines the optimal ignition timing for each cylinder from various operating conditions and determines the second timing; ignition period calculation means for calculating the cycle of the second timing determined by the ignition timing determination means; and first timing determination means for determining the first timing according to the period of the next ignition cycle. It is characterized by With the above configuration, the present invention makes the energization time of the ignition coil a constant value regardless of the ignition cycle, that is, the anti-knocking control that operates mainly for each cylinder, the engine rotation speed, etc., and also sets the constant value to a certain value. This can be set variably depending on the operating condition of the vehicle.

[Effect]

In order to easily understand the operation of the present invention, a description will be given with reference to FIG. 'M2 which embodies a signal waveform. The advance angle is determined for each cylinder according to various operating conditions, and the optimum ignition timing is determined from the advance angle and the engine rotation speed.
The second period will be decided. As a result, the ignition cycle commanded by the second timing of the ignition timing control signal becomes irregular as shown in FIG. 2(a). Note that the first ignition period TI, second ignition period Ta, third ignition period T1, etc. are the second timing t02°t12. of the previous ignition period.
Starting from the time when t22 etc. is exceeded, the first period is determined 1゜t
21. t31 etc. and then the second period t12. t22
．． It is defined as ending at t32 or the like. Also, the period between the first period and the second period indulged in each ignition cycle (
Hereinafter, this period will be referred to as "control period") is Td +,
Defined as Tdz and Tds, the period during which no current flows through the ignition coil in each ignition cycle (hereinafter referred to as "cutoff period") is 0. , Da, and the period during which current is flowing through the ignition coil (hereinafter referred to as "current-carrying period") is defined as W, , W.
, , W, is defined. Further, the timing at which the igniter starts energizing the ignition coil is determined by the control period in the previous ignition cycle. Therefore, the cutoff period of the second ignition cycle and the third ignition cycle is 0.
2. DI is a function of control periods Td+ and Td*, so D 2 = P (Td, )
-α0[13=I' (Td,)
-(It can be written as Jυ. Also, the energization period W2, L of the second ignition cycle and the third ignition cycle is W2=T2-D2=Tff-F (Td +)=c (
T2. Tdl) -α of W3=T3-D3
=T3-P (Td2)=G (T3.Td2)
-03- In boat fishing, the energization period 111+1 in the i+1st ignition cycle is the period TI in the 1+1st ignition cycle.
+1 and the control period Td+ in the i-th ignition cycle,
Wt, + = G(T+++, Tdl)
It can be expressed as αa. Therefore, in order to set the energization period V4I in each ignition cycle to a constant value W regardless of the ignition cycle TI, the control period Td+ indulging in the first ignition cycle should be changed to the i+1st ignition cycle T,
+1 and constant value W, Tdl-K(T1.1.W)
-45), W,+,=G(T1.,, K(T1.,,W))=W
−αe. Further, the constant value W may be variably set depending on the operating state X, such as the temperature of the coolant, the mixture ratio, and the advance angle. That is, W=II(X,, -,X,)
As −α1, Tdt−K(T+++, 1l(X+, −, X,
,))=R(T1.,,X,, -,X,)
-(ie, the control period Td can be determined. As described above, by setting the control period Td in the i-th ignition cycle according to the period TI+1 of the next ignition cycle, the control period Td can be determined according to the period TI+1. It is possible to obtain a constant energization period that does not depend on the voltage.The signal waveform in Fig. 2 referred to in the above explanation shows one example, and the signal waveform is not limited to the waveform in Fig. 2. Moreover, the integral waveform of the igniter is just one example.

[Examples] The present invention will be described below based on specific examples. FIG. 1 is a block diagram showing the configuration of an ignition system using an ignition timing control device according to a specific embodiment of the present invention. 3 is a sensor group for detecting various operating conditions;
A vacuum sensor 31 for detecting the engine load condition based on the engine intake pressure, a water temperature sensor 32 for detecting the coolant temperature, a throttle position sensor 33 for detecting the throttle position, and a crank angle of 30° in synchronization with the rotation of the crankshaft. Crank angle sensor 34 that generates a signal every time
, a cylinder discrimination sensor 35 that outputs a top dead center signal for each cylinder;
Consisting of a knock sensor 36 that detects the occurrence of knocking for each cylinder, a starter operation sensor 37 that detects the activation period of the starter, an air conditioner operation sensor 38 that detects the operation period of the air conditioner, and a vehicle speed sensor 39 that detects the vehicle speed. . 1 is an ignition timing control device, which controls engine load, rotation speed,
This device calculates the advance angle according to the knocking occurrence situation, determines the optimal ignition timing, that is, the second timing, for each cylinder, determines the first timing, and outputs an ignition timing control signal. The ignition timing control device 1 has an input interface circuit 11 and an input interface circuit 12 that input analog signals and digital signals indicating various operating states from the sensor group 3.
The analog signal inputted via the A/D converter 13 is inputted to the CPU 15, and the digital signal is inputted directly to the CPU 15 via the input interface circuit 12. The CPU 15 also includes a ROM 16 that stores a control program for outputting an ignition timing control signal, a table for determining the advance angle from the operating state of each cylinder, constants, etc., a RAM 17 for temporarily storing numerical values,
An output interface circuit 14 is connected. The RAM 17 includes an advance angle memory 171 that stores the advance angle determined for each cylinder, an ignition cycle memory 172 that stores the determined ignition period, a control period memory 173 that stores the determined control period, and a control period memory 173 that stores the determined control period. 1st to remember the 1st period
A timing memory 174, a second timing memory 175 for storing the determined second timing, and a control signal flag 176 for storing whether the ignition timing signal is at a high level or a low level are provided. Further, 5 is an igniter, which is a device for controlling the energization period of the ignition coil 60 by the power transistor 50 based on the above-mentioned ignition timing control signal, and causing the ignition plug 7 of each cylinder to spark via the distributor 2. 9
is a battery, which is connected to the ignition coil 6 via the ignition switch 8. The igniter 5 is realized by a combination of known integral circuits, receives the ignition timing control signal shown in FIG. 2(a), generates the integral signal shown in FIG. 2(b), and generates the integral signal shown in FIG. 2(c). This device outputs the ignition control signal shown in FIG. 1 to the power transistor 50, and its circuit configuration is known. To explain the effect using FIG. 2, first, at the first time tll of the first ignition cycle, the capacity is charged from the initial value 0 using a charging circuit having a constant long time constant, and an increasing straight line Ll with a slope a is charged. An integral signal shown is generated. Next, the second
At time t12, the capacitance is discharged by a discharge circuit with a constant long time constant, and an integral signal shown by a decreasing straight line L2 with a slope b is generated. Then, at a time t20 when the decreasing straight line L2 exceeds a preset constant threshold value Eth, another discharge circuit with a short time constant is operated, and its capacity is rapidly reset to the initial value O, and the next first discharge circuit is operated. By repeating the above-described charging and discharging operations from time t21, the integral signal shown in FIG. 2(b) is generated. Then, an ignition control signal is generated as shown in FIG. 2(C) based on the ignition timing control signal and its integral signal. That is, at time t12. At a second period such as t22, it falls to a low level and a decreasing straight line L2 is a preset constant threshold value E.
Time t20 when exceeding th. An ignition control signal that rises to a high level at t30 or the like is output to the base terminal of the power transistor 50. As a result, the primary winding of the ignition coil 6 is energized while the ignition control signal is at a high level, and the current waveform flowing through the ignition coil becomes as shown in FIG. 2(a). Next, the operation of the ignition timing control device 1 will be explained based on a flowchart showing the processing procedure of the CPU 15. This embodiment relates to control of a four-cylinder, four-cycle engine. When the main key of the automobile is turned on, the main program shown in FIG. 3 is executed. In step 100, the current ignition cycle number i and the next ignition cycle number j are determined based on the top dead center signal TDC output from the cylinder discrimination sensor 35. l and j repeat the values 1 to 4, and j is a number that precedes i by one cycle. In this way, in addition to the initial setting of the ignition cycle number, necessary initial value settings are performed. Next, in step 102, various signals are input from the sensor group 3 and the operating state is determined. Then, a lead angle table set in the ROM 16 is searched based on the engine speed and engine load, and the optimum lead angle for the current operating condition is determined. Further, the knock state of each cylinder is determined based on the output signal from the knock sensor 36, and if a knock state is detected, the advance angle is delayed to an angle at which knock is no longer detected. In this way, the advance angles θ1 to θ4 at that time are determined for each cylinder, and the values are stored in the advance angle memory 171. The process then proceeds to step 106, where various other processes are executed, and the process returns to step 102, where the above processes are repeatedly executed. As a result, the constantly changing driving conditions are detected, and the optimum advance angle corresponding to the conditions is updated every moment. While the above main program is being executed, the cylinder discrimination sensor 35
When the top dead center signal TDC is output from the top dead center signal TDC, the program shown in FIG. 4 is activated by the top dead center signal TDC interruption. In step 200, the above-mentioned top dead center signal TDC is generated every 180 degrees of crank angle, and by measuring the elapsed time since the previous interruption,
The time TM required for 0° rotation is calculated, and the time T14
The rotational speed V of the crank angle is calculated from . Next, the advance angle θ corresponding to the ignition cycle is read from the advance angle memory 171.
1. θj is read out, and the ignition period T in the j-th ignition period is calculated using the following equation and stored in the ignition period memory 172. T, = (180+θ1-θJ)/V
“” α [Yes] Next, in step 204, the i-th
The control period Tdl in the ignition cycle is calculated by the following equation. Td+-a/b+TJ
'-'elHere, since the igniter 5 controls the energization period with the characteristics shown in FIG. 2(C), the above aa formula and 05
Equation 1 is concretely expressed as follows. Wj=Tt-a/b-Tdt+Bth/b
-”12DTdt-b/a
-(Tj+[!th/b-11)
− becomes @. In particular, when keeping the energization period constant at W = 8th/b, Ttlt-b/a -TJ
-...(c). Therefore, in step 204, the control period Td+in the i-th ignition cycle is calculated based on the formula, that is, as a value obtained by multiplying the period T in the next ignition cycle by a constant ratio,
The value of the calculated control period Tdt is stored in the control period memory 1.
73. Next, the process moves to step 206, where the advance angle θ is calculated as θl/v.
is converted into time Tal. Then, in the next step 208, a second timing Tfi based on the input of the top dead center signal TDC in the i-th ignition cycle is calculated by the following formula, and the second timing Tf is stored in the second timing memory 175. be done. rr l-TM-ra t
, -l+) Next, the process moves to step 210, and the first time Ts, which is based on the time when the top dead center signal TDC is input, is calculated by the following formula, and the first time Tst is calculated from the first time memory 1.
74. Tst-Tfi-Td+
- The first ignition timing control signal is
This means that the first timing Ts and second timing Tfr in the ignition cycle have been calculated. Next, the process moves to step 212, where the ignition cycle numbers i and J are
are updated by 1, respectively, and if it is determined in step 214 that the value of i is equal to 5, then step 216
The value of i is set to the initial value 1. If it is determined in step 218 that the value of `` is equal to 5, the value of j is set to the initial value 1 in step 220. That is, since this embodiment assumes a four-cylinder engine, the ignition cycle number 1. j is repeatedly updated in the range of 1 to 4 every time the top dead center signal TDC is input. Next, in step 222, the first period memory 174
Then, the first period Ts is successively outputted, and the first period Ts is set in the timer, and the present interrupt program ends and returns to the main program shown in FIG. 3. Then, while the main program is being executed, a timer interrupt occurs when the time set in step 222 has elapsed, and the timer interrupt starts the timer interrupt program shown in FIG. 5. In FIG. 5, in step 300, the control signal flag 1
It is determined whether or not 76 is on, and the control signal flag 17
If 6 is not on, proceed to step 302,
The ignition timing control signal is brought to a high level via the output interface circuit 14. Next, proceeding to step 304, the control period memory 17
3, the control period Tdt is read out, and its value is set in the timer. Then, in step 306, the control signal flag 1
76 is set to ON, this timer interrupt program ends and returns to the main program. Next, while the main program is being executed, a timer interrupt occurs when the time set in step 304 has elapsed, and the timer interrupt restarts the program shown in FIG. 5. In step 300, it is determined whether the control signal flag 176 is on, but since the control signal flag 176 has already been set to on in step 306, step 300
The determination becomes YC3, and the process moves to step 308, where the ignition timing control signal is set to a low level via the output interface circuit 14. Then, in the next step 310, the control signal flag 176 is set to OFF, the timer interrupt program ends, and the program returns to the main program. Through the above processing, an ignition timing control signal that sets the control period TdI to a high level is output. FIG. 6 is a timing chart showing the relationship between the above processing procedure and output signals. Current ignition cycle, i.e. 1st
One cycle TM of the top dead center signal and the rotational speed V are measured from the detection timing of the top dead center signal TDC+ in the ignition cycle and the detection timing of the top dead center signal TDCI-1 in the previous ignition cycle. Then, assuming that the opening speed for at least two periods remains unchanged, the detection timing of the next and subsequent top dead center signals TDC, , TDCj◆1 is predicted from the current rotational speed V. Then, the current rotational speed V and advance angle θ1. θ,
From this, the next ignition cycle, that is, the j-th ignition cycle TJ is determined. From the period TJ, the current ignition period, that is, the control period Tdl of the ignition timing control signal of the i-th ignition period is determined. Then, the time Tar s corresponding to the advance angle θ1, that is, the time measured from the predicted top dead center signal TDC, is calculated, and then the first period measured from the top dead center signal TDC in the current ignition cycle. Determination, is calculated. Further, the first timing determination I in the i-th ignition cycle is determined from the second timing Tft and the control period TdI, a timer is set according to the value, and a predetermined first timing determination I is determined by the timer interrupt. At the second timing Tf, an ignition timing control signal whose signal level changes is output. In addition, in the above program description, the time from when the top dead center signal interrupt program or the timer interrupt program is started until the predetermined value is set in the timer in step 222 or steps 3 and 4 is ignored. However, in reality, there is a slight time delay as shown in the timing chart of FIG. 6, and the value actually set in the timer is corrected by that time delay. Furthermore, in the above embodiment, the first timing is determined using the top dead center signal TD.
The setting is based on the time when CI occurs, but as shown in Figure 7, the crank angle signal 30°CA is output every 30°.
It may be set based on. That is, the interrupt processing in Fig. 4 is performed using the crank angle signal 30° CA to which the first period belongs (in the example shown in Fig. 7, 4X30''CA=
120' C8) may be executed in synchronization with the detection. In this case, the rotational speed is determined by the crank angle signal 30.
The calculation may be performed every time °CA occurs. Then, in the process shown in Fig. 4, the first period is calculated from the crank angle signal used as the reference, the value is set in the timer, and when the set time has elapsed, the timer interrupt program shown in Fig. 5 is executed. You may also start it. In the above embodiment, a 4-cylinder 4-stroke engine was described, but the present invention can also be applied to a 6-cylinder engine or the like. Effects of the Invention The present invention provides ignition timing determining means for determining the second timing by determining the optimum ignition timing for each cylinder from various operating conditions, ignition period calculating means for calculating the cycle of the second timing, Since it has a first timing determining means that determines the timing according to the period of the next ignition cycle, the first timing of the ignition timing control signal can be appropriately set, and the first timing and the second timing can be set appropriately. It is possible to optimally set the period between the ignition coil and the ignition coil to make the energization time of the ignition coil constant regardless of the ignition cycle, or to change the constant value depending on a certain operating state. Therefore, the ignition energy can be controlled to an optimal value in accordance with the operating state, and ignition failure, heating of the ignition coil, etc. can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an ignition system using an ignition timing control device according to a specific embodiment of the present invention. FIG. 2 is a timing chart illustrating the operation of the device of the embodiment. FIG. 3, FIG. 4, and FIG. 5 are flowcharts showing the processing procedure of the CPU of the device. FIG. 6 is a timing chart showing the effect. FIG. 7 is a timing chart showing the operation of an ignition timing control device according to another embodiment. FIGS. 8 and 9 are timing charts showing the operation of a conventional ignition device. 1°・Ignition timing control device 3-・-Sensor group 5-Igniter 6゛・・Ignition coil 7・・Spark plug 8-
...Ignition switch 9P battery Patent applicant Nippondenso Co., Ltd. Agent Patent attorney Osamu Fujitani Figure 2 Figure 3 Figure 4 Figure 5 Discussion

Claims (3)

[Claims] (1) An ignition timing control signal that includes a first period and a second period delayed from the first period in one period and instructs the ignition timing of the cylinder corresponding to the period at the second period, the first period. In the ignition timing control device, which outputs an output to an igniter that controls the energization timing of the ignition coil in the next ignition cycle according to the time difference between the timing and the second timing, the optimum ignition timing is determined for each cylinder from various operating conditions. ignition timing determining means for determining a second timing; ignition cycle calculating means for calculating the cycle of the second timing determined by the ignition timing determining means; 1. An ignition timing control device comprising: first timing determining means for determining an ignition timing. (2) The first timing determining means determines the first timing such that a ratio of the period between the first timing and the second timing to the next ignition cycle becomes a predetermined constant value. An ignition timing control device according to claim 1, characterized in that: (3) The first timing determining means determines the period between the first timing and the second timing depending on the period of the next ignition cycle and the operating state. The ignition timing control device described in .