JPS6231189B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an ignition timing control method that performs feedback control of ignition timing in order to improve engine output and fuel consumption. Unless there are special reasons such as knocking or problems with exhaust gas characteristics, the engine's ignition timing should be adjusted to the operating conditions of the engine so that the engine's output can be maximized and fuel consumption can be minimized at the same time. It is adjusted by the rotation speed, intake pipe pressure, etc. Generally, when controlling engine ignition timing with a microcomputer, engine speed, intake pipe pressure, intake air amount, throttle opening, etc. are expressed as digital quantities and calculated by arithmetic operations according to algebraic functions. The optimal ignition timing corresponding to the engine speed, intake pipe pressure, intake air amount, etc. is determined by interpolation and synthesis from stored maps. However, these conventional methods have limitations and some loss in power and fuel consumption. For example, problems such as variations in individual engines, changes in environmental conditions, variations in sensors such as intake pipe pressure sensors or intake air amount sensors, and deterioration cannot be addressed by this method alone. In order to eliminate these losses and maximize engine output, methods have been devised to feedback control the ignition timing.
It is known from the specification of No. 3142967. According to this, the engine was operated at two different ignition timing points near the target ignition timing, and among these two points, the rotation speed Nr when operating at the delayed ignition timing, and then the engine speed Nr when operating at the advanced ignition timing. Detects the rotational speed Na at the time, compares the magnitude of both rotational speeds, and when Nr<Na, the target ignition timing is advanced by a predetermined value, and when Nr<Na, it is corrected to be delayed by a predetermined value. Then,
The engine is controlled to the optimum ignition timing to provide maximum torque. However, when determining changes in output based on rotational speed, this method determines whether the change in rotational speed is due to ignition timing or whether it is due to external factors (acceleration, Because there is no ability to determine whether the cause is due to accelerator operation during deceleration, etc., the ignition timing is corrected in the opposite direction to the ignition timing that provides maximum torque during acceleration/deceleration or when going up or down a slope, resulting in a decrease in rotation speed and output. In some cases, this caused deterioration of fuel efficiency. In addition, corrective control is always required in response to changes in engine operating conditions (rotational speed and intake pipe pressure).
Even when returning to the same operating conditions, the feedback control had to be restarted from the beginning. The present invention has been made in view of the above problems, and uses a two-dimensional map that calculates the target ignition timing based on the first operating state (rotational speed, etc.) and the second operating state (intake pipe pressure, etc.) of the engine. at least two different ignition timings near the target ignition timing and different from each other.
The engine is operated alternately for a predetermined period at at least two selected ignition timing points, and the engine rotation speed signal and torque signal are obtained when operating at each of these ignition timing points. Detect signals or operating status signals related to these,
The target ignition timing is determined to maximize the engine output by comparing the operating state signals of at least three consecutive points among the operating state signals obtained when the engine is operated with the at least two ignition timing points. It is characterized by determining whether the ignition timing is advanced or delayed from the optimum ignition timing, and corrects the value of the two-dimensional map according to the result of this determination. Identify whether the engine speed, torque, etc. have changed, or whether the engine speed, torque, etc. have changed due to changes in the ignition timing at at least two different points, and correct the target ignition timing to the optimal ignition timing to maximize engine output. The aim is to maximize fuel efficiency while minimizing fuel consumption. Further, the present invention provides a means for using the two-dimensional map when the frequency of use of the most frequently used area of the two-dimensional map is equal to or higher than a predetermined ratio during the period for determining whether or not the ignition timing is at the optimum ignition timing. By correcting the area with the highest frequency or its vicinity, errors can be avoided when the usage area of the 2D map spans a wide range and the main usage area cannot be determined while detecting the three-point driving status signal. Prevents modification of ivy areas,
Furthermore, if the value used in the two-dimensional map deviates from a predetermined area, detection of the driving status signal is interrupted and new detection is started from the deviated area, thereby preventing erroneous corrections in transient conditions. The purpose is to make it possible. The method of the present invention will be explained below with reference to examples shown in the drawings. FIG. 1 is a block diagram of a control system in which the present invention is applied to a 4-cylinder engine, where 1 is a 4-cylinder, 4-cycle engine, and 2 is a water temperature sensor that detects the temperature of the engine's cooling water. 3 is a starter, and 31 is a starter switch. 5 is a rotation sensor that measures the rotation angle position of the engine 1, which generates a top dead center signal when the engine 1 rotates and reaches the top dead center position, and equally divides one revolution of the engine from the top dead center position. A rotation angle signal is generated each time the motor rotates by a certain angle (in this embodiment, the crank angle is 30 degrees; all angle units hereinafter are crank rotation angles). 10 is a carburetor, and 8 is a pressure sensor built into the control computer 6. Pressure is transmitted from the intake manifold 9 of the engine 1 to a pressure input port through a pipe 11, and measures the intake manifold pressure. 4 and 7 are ignition actuators of this system. In this embodiment, a dayless double coil system using two coils is adopted, where 4 is an ignition coil and 7 is an igniter. The control computer 6 determines the engine speed from the time interval of the rotation angle signal generated by the rotation sensor 5, calculates the intake manifold pressure from the output voltage of the pressure sensor 8, measures the engine operating state, and starts the ignition. Control the timing. Furthermore, in order to control the ignition timing to a specific value when starting the engine, the voltage supplied from the starter switch 31 to the starter 3 is inputted to the control computer 6 as a starter signal. Further, in order to change the energization time of the ignition coil 4 in accordance with the battery voltage, the battery voltage is taken into the control computer 6 as a battery voltage signal. Reference numeral 12 denotes a power source that generates the voltage required by the control computer 5 from the voltage of a battery 13 mounted on the vehicle. FIG. 2 shows a block diagram for explaining the control computer 6 in detail. 60 is a central processing unit (CPU) that calculates ignition timing and is made by Texas Instruments (TI) with a 16-bit configuration.
TMS9900 is used. Reference numeral 70 indicates a read-only memory unit (ROM) that stores control programs and control constants, and 69 indicates a temporary memory unit (RAM) that is used to store control data while the CPU 60 is operating according to the control program. Reference numeral 71 is a non-volatile RAM that stores a two-dimensional map of the optimal ignition timing that provides maximum torque, and has an auxiliary power source so that the contents of the RAM remain even after the ignition switch is turned off. 61 is an interrupt control unit which notifies the CPU 60 of the occurrence of an interrupt with three levels of priority. The interrupt factors in this embodiment include an interrupt caused by the generation of a rotation angle signal from the engine rotation sensor 5, and an interrupt caused by the CPU
There are three types of interrupts: a program interrupt which is caused by the program interrupt output port 60 itself setting the level of the program interrupt output port of the digital input/output port 64 to "0", and a timer interrupt which is caused by the timer every 8 ms. The timer section 62 is composed of a 16-bit counter that counts an 8 μs clock signal and a latch that stores and holds the counter value every time the rotation angle signal of the rotation sensor 5 is generated. Therefore, in the interrupt processing for generating the rotation angle signal, the CPU 60 reads the value of the crank angle counter section 63 to know the rotation angle position of the engine, reads the latch value of the timer section 62, and performs this operation for two rotations. By determining the difference between the latch values at each angular position, it is possible to measure the time it takes the engine to rotate between two rotational angular positions, and also to measure the engine speed. The crank angle counter section 63 has a lower digit in hexadecimal.
This is a high-order digit 4-digit counter, which counts up based on the rotation angle signal of the rotation sensor 5. When the rotation angle signal next to the top dead center signal is generated, this counter is reset to the value "0" and the engine rotation is increased. can be synchronized with. Therefore, the value of the crank angle counter is
By reading it out by the CPU 60, the engine rotational angular position can be known in units of 30 degrees crank angle. The digital input/output port 64 is a port used for inputting and outputting logic signals, and inputs a signal from the starter switch 31 indicating that the starter 3 for starting the engine is in operation, and also inputs a program interrupt signal to the interrupt control section. 61. Signals from the engine coolant temperature sensor 2, intake pipe pressure sensor 8, and battery 13 are converted into analog-to-digital (A/D) signals at the analog input port 65, and then stored in the RAM 69 by the DMA control unit 66.
DMA transfer is performed. Therefore, in this example, CPU6
0 is not directly involved in A/D conversion, and the latest A/D conversion data required can be used by accessing a predetermined address in the RAM 69 when necessary for calculation. In addition, in this system
By connecting the operation panel 67 as necessary using the DMA control unit 66, data can be written to the RAM 69, ROM 70, RAM 69, non-volatile
Data in the RAM 71 can now be read. Further, the state (RUN, HOLD) of the CPU 60 can be controlled from the operation panel 67. More detailed contents of each of the above circuit sections will be sequentially explained below. A detailed circuit diagram of the crank angle counter section 63 is shown in FIG. The crank angle counter section 63 includes two sensors 50 and 51 of the rotation sensor 5 attached to the shaft of a normal distributor that rotates once every two revolutions of the engine crankshaft.
This signal indicates the current position of the crankshaft in decimal notation. Sensor 51 of rotation sensor 5
The crank angle signal 5b (FIG. 3b) is passed through low-pass filters 106, 107 and transistors 109,
A D-type flip-flop 114 (for example, manufactured by TI
SN74LS74). flipflop 1
14 is for preventing the contents of the counter 125 from changing due to count-up during data transfer by the crank angle READ command from the CPU 60. During the crank angle READ (signal terminal 401 is logic "0"), the crank angle signal is 5b's input clock 400 is stopped by the AND element 113. The Q output of the flip-flop 114 is a synchronous 4-bit counter 125 (for example, manufactured by RCA).
CD4520B) is input to the CK (clock) terminal. This counter 125 is a 2-bit counter in the ternary part and a 2-bit counter in the quaternary part by the NAND gate 1.
28 and 124 are connected in series, and the whole operates as a (3×4=) decimal counter.
The contents of the counter 125 correspond to the position of the crankshaft and are counted up at every trailing edge of the crank angle signal 5b. The counter 125 is set by the crank angle READ command from the CPU 60.
The contents of Batsuhua 126 (for example, manufactured by TI)
SN74LS244) is output to the data bus 404. The TDC signal 5a (Fig. 3a) of the sensor 50 of the rotation sensor 5 is transmitted to #1 and #4 of the crankshaft.
This is a signal that indicates the TDC position of the cylinder, and every time the crankshaft passes the top dead center of #1 and #4 cylinders, 1
Outputting pulses. Similar to the crank angle signal 5b, this TDC signal 5a is waveform-shaped by a resistor 100, a capacitor 101, a transistor 103, and a Schmitt input NAND element 105.
CD4013B) is input to the D (data input) terminal. A crank angle signal is input to the CK terminal of the flip-flop 118, and the Q output is connected to the D terminal of the D-type flip-flop 119. Therefore, at the trailing edge of the first crank angle signal after the TDC signal 5a is inverted to logic "1", the flip-flops 119, 120 and the NAND element 121 generate one pulse (the pulse width is determined by the frequency of the CK2 signal 407). generate the counter 125.
RESET (counter contents = “0000”). In other words, TDC corresponds to “0000” and crank angle is 90°.
CA corresponds to “0100”. counter 125
RESET is the T.RESET signal 402, which is the system initialization signal, and the T.RESET signal 402 from the CPU 60.
It is also performed from the RESET instruction 406. Furthermore, the fourth
The circuit diagrams from Figure to Figure 12 are marked with 〓.
The TTL logic element and other logic elements use C-MOS logic elements. This is because the CPU 60 operates at high speed, so it is impossible to use a C-MOS interface in terms of time. Next, the timer section 62 will be explained with reference to FIG. A clock CKI having a frequency of 3 MHz supplied from the CPU 60 via a terminal 400 is divided by three by D-type flip-flops 200 and 201.
This clock (CK2) also has a 4-bit counter of 20
2, and after being divided by 8, the 8bit counter 2
08 as a clock. The 8-bit counters 207 and 208 constitute a 16-bit real-time timer, and count the time from 0 to 524280 μs. This timer is activated by the 8-bit latch 209, 21 by the leading edge of the crank angle pulse of the crank angle counter section 63 through the terminal 403.
The current time is latched to 0 (for example, CD4508B manufactured by RCA). The latched time is
In response to the timer READ command sent from the CPU 60 through the terminal 408, the buffers 211 and 212 are further transferred to the CPU 60 through the data bus 404. Flip-flops 204 and 205 output a 2 μs wide latch strobe pulse at the leading edge of the signal at terminal 403. 3 inputs
AND206 is to prevent the count up time of the 16bit timers 207 and 208 from overlapping with the time latch time, and when the LSB output of the counter 202 is "0", the latch timing is set to a maximum of 1 μs.
It's delayed. Next, the interrupt control section 61 will be explained with reference to FIG. First, every time a crank angle signal is input from terminal 403, a gear interrupt flag (D-type flip-flop)
302 is set to "1", and an interrupt request signal is sent to the CPU 60 via the inverter buffer 306 and the terminal 444. When this interrupt is accepted, the gear interrupt flag is sent from the CPU 60 through the terminal 440 by the gear interrupt processing program described later.
will be reset. Similarly, when the program interrupt port is set to "1" during the gear interrupt program, the program interrupt flag (D flip-flop) 301 is set through the terminal 441, and an interrupt request is sent to the CPU 60. This flag is also reset through the terminal 442 by a command from the CPU 60.
Furthermore, the 16-bit timer (20 bits) of the timer section 62
7,208) through terminal 415.
8.192ms clock causes 8ms interrupt flag (D
(type flip-flop) is set, and an interrupt request is transmitted to the CPU 60 via a terminal 446. That is, this interrupt occurs every 8.192ms and is used as a time base for the software. This interrupt is also reset by an instruction from the CPU 60. Next, the DMA control unit 66 is shown in FIGS.
Shown in Figure 0. Terminals 409, 410, 411, 41
Reference numeral 2,413 is for generating a HOLD request signal (terminal 437) for causing the CPU 60 to temporarily stop the execution of the program, and the output signal from the timer unit 62 in FIG. 5 is input thereto. Timer section 6
2 16bit real time timer 207,208
bit 2 (terminal 413) and bit 3 (terminal 4)
12) are both “1”, AND gate 603
The output of is "1". In other words, the waveform is as shown in FIG. 8o. Similarly, the output of the 3-input AND 605 is as shown in FIG. 8P. In addition, 61
8 to 622 and 644 to 646 are resistors for CMOS input protection. The DMA shown in this example has 8 channels, and all channels are connected every 1 ms.
Transfers data between RAM69. The first 7 channels out of 8 channels (CHO in Figure 8 o)
-6) are for transferring A/D converted data, and the last channel CH7 is used for data transfer with the operation panel 67. In the case of A/D converted data, as shown in FIG. AND gate 608
When becomes "1", if there is no external HOLD request signal from the operation panel 67 to the computer (terminal 427 is "1"), the output of AND gate 605 becomes "0" (therefore, the output of 608 becomes "1"). ”), register 624 (for example, 74LS175 manufactured by TI)
The D input of becomes "1". CK of register 624
For input, 3MHz clock from CPU60 is connected to terminal 4.
26. (Figure 8r). Immediately after the D input of the register 624 changes to “1”, the Q output of the register 624 is “0”, so the AND
Output of gate 642 is “0”, NAND gate 60
1 becomes “1” and the CK of register 624
The 3MHz clock is directly applied to the input, and at the next clock after the D input of the register 624 changes to "1", "1" is taken into the register 624, and the Q output becomes "1" as shown in FIG. 8q. When the Q output of 624 becomes "1", the output of AND gate 642 changes to "1", and the tri-state output
The output of the NAND gate 643 (for example, 74LS38 manufactured by TI) becomes "0", and a HOLD request signal ("0") for starting DMA is output to the CPU 60 (see t in FIG. 8). The CPU 60 receives this HOLD request signal from the terminal 431 and sends it to the receiving terminal 425 after the currently executing machine cycle ends.
FIG. 8 u which outputs the HOLDA signal "1". terminal 4
37 is “0” and the HOLD request signal is output.
Since the output of the NAND gate 601 is “0” until the HOLDA (terminal 425) signal becomes “1”, 3M
The Hz clock (terminal 426) is connected to register 625.
Not supplied to CK pin. When HOLDA becomes “1”, a clock is input to the CK terminal of register 625, “1” is taken into register 625, and Q
The output becomes "1". Further, at the next clock, the Q output of the register 626 becomes "1", and at the next clock, the output of the register 627 becomes "0". When the output of the register 627 becomes “0”, the output of the NAND gate 643 becomes high impedance.
The HOLD request is released and the DMA cycle is completed. When the HOLDA signal becomes "1", the AND gate 638 becomes "1" and the tri-state output
The output of the NAND gate 641 becomes "0" only during the period when the HOLD request signal () is "0" and the HOLDA signal is "1", and the RAM 6
9 is a memory use selection signal (,436)
issue. Furthermore, only when the Q output of the register 625 is "1" and the output of the register 626 is "1", the AND gate 639 becomes "1", and CHO~
While CH6 is selected, 3-input AND gate 6
Since the output of 05 is "0", the inverter 61
The output of 2 is “1”, and the tri-state NAND
The gate 640 has a memory as shown in FIG.
WRITE signal to RAM69 (, terminal 435)
is output. Furthermore, while the memory use selection signal is “0”, the output of the NAND gate 628, that is, the READ signal to the memory (DBiN, terminal 4
31) is “0”. While the HOLDA signal is “1” (during a DMA cycle), the CPU 60 is stopped, and the control lines such as , DBiN, , etc.
Drives from the CPU side of the address bus and data bus are in a "high impedance" state. Therefore, during this period, data is transferred directly from the DMA control unit 66 to the RAM 69. In the case of transferring A/D conversion data of CH0 to CH6, the inverter 60
The output of 6 is "1", and the output of terminal 420, i.e.
The NAND gate 629 outputs a signal similar to that shown in FIG.
A/D conversion address registers 530, 53 in Figure 0
1 strobe input. In other words, during the period when CH0 is "0", A/D converted data is output on the data bus 404, and CH0
The address corresponding to .about.6 is output on address bus 440. The data output on these buses is written into the RAM 69 by signals.
When there is an external HOLD request signal (terminal 427) from the operation panel 67 (“1”), the A/D conversion DMA cycle of CH0 to CH6 is not performed. In other words, the output of the NAND gate 607 becomes "0",
Even if the output of the AND gate 603 becomes "1", the D input of the register 624 remains in the "0" state, so the DMA cycle is not started. Next, the DMA cycle of CH7, which transfers data between the operation panel 67 and the RAM 69, will be explained. terminal 428
The terminal 429 receives the R/ signal from the operation panel, the terminal 430 receives the continuous READ signal, and the terminal 414 receives the approximately 128 ms clock signal supplied from the timer section 62. First, when a data write request is issued from the operation panel 67 to the RAM 69, the terminals 428, 429, and 430 become "0". The outputs of AND gates 605 and 603 become “1” (o, p in Figure 8) and the DMA of CH7
The cycle begins. Registers 615, 616
As a result, when the terminal 429 falls from “1” to “0”, a positive pulse with a width of 1.0 ms is sent to the AND gate 6.
One occurs at the output of 17. This pulse becomes a 128 μs negative polarity pulse at the NAND gate 609,
It passes through the NAND gate 608 and the AND gate 604 and is input to the D input of the register 624 as a 32 μs positive pulse. RAM6 from operation panel 67
For a WRITE request to 9, ,HOLDA,
, , DBiN control lines are driven in exactly the same way as in the DMA data transfer of the A/D conversion data. (FIG. 8 t to w) Furthermore, the signal terminals 434 and 432 that cause the operation panel 67 to output the address to be transferred to the RAM 69 and the contents of the register storing the data onto the address bus and the data bus, respectively, are set to "0'' period, a positive pulse is output as shown in FIG. 8x. RAM69, ROM70 from operation panel 67
When a data read request is made to the terminal, terminals 429 and 430 become "0" and terminal 428 becomes "1". In this case, in the DMA cycle, the signal (terminal 435) on the computer control line remains "1" even during the period when the memory use selection signal (terminal 436) is "0", but the output of the AND gate 611 is Since it is "1", the DBiN signal (terminal 431) is "1".
Other control lines HOLD, HOLDA,
This is the same as the A/D conversion data transfer cycle and the data write cycle from the operation panel 67. When the continuous READ signal (terminal 430) is "1", the output of the NAND 613 generates a 128 ms clock. This is caused by the NAND gate 614, and the RAN6 is sent from the operation panel 67 every 128ms.
9. Since this is equivalent to a data read request to the ROM 70, a DMA data transfer cycle occurs once every 128 ms from the RAM 69 and ROM 70 to the operation panel 67 as described above. In addition, from the operation panel 67
The DMA cycle is triggered by an external HOLD request signal (terminal 42).
7) will be executed even if there is. Next, the analog input port 65 will be explained with reference to FIG. Filters 500 to 506 of resistors and capacitors connected immediately after the input terminal of each sensor are for removing noise components superimposed on the signal line. Three sensor inputs are 8 channel multiplexer 514
(for example, CD4051B), and one of the inputs is selected by the level of address inputs A, B, and C. That is, for example, when A, B, and C are "0", "0", "0", the CO input is selected, and when they are "1", "0", "0", the CO input is selected.
C1 input is selected. Address inputs A, B, and C of the multiplexer 514 are connected to real-time timers 207 and 208 of the timer section 62 via a level converter (for example, CD40109B) 515. Therefore, CO→C1→C2 every 128μs
The channels to be selected are switched as →...→C0, and one channel is selected once every 1 ms.
Terminal 412 also has real time timer 207, 20
8 and generates a 64μs clock. That is, at the same time as the address of multiplexer 514 is switched, terminal 412 rises from "0" to "1". At that time, the inverter 52
0,524,NANO523, resistor 521, and capacitor 522 generate an A/D start pulse of several μs, and successive approximation type A/D converter 517
(e.g. Bur Brown ADC80AG) CONV,
It is input to the CMD terminal and A/D conversion starts. The output of multiplexer 514 is address input A,
One input selected according to the values of B and C is output as is, and after current amplification by an operational amplifier 516 (for example, μPC151A manufactured by NEC Corporation), is input to an analog input terminal of an A/D converter 517.
After the conversion start signal is applied to the CONV and CMD terminals, the A/D converter 517 converts the analog input into 12-bit digital data in about 40 μs and outputs it to B0 to B11. The converted digital data is written by the DMA control unit 66 as 12-bit data B0 to B11 through buffers 518 and 519 to the address corresponding to the selected channel of the RAM 69 in a DMA data transfer cycle that starts 96 μs after application of the conversion start signal. It can be done. Next, the energization ignition control section 68 will be explained in detail with reference to FIGS. 11, 12, and 3. The CPU 60 calculates the current position of the crankshaft by 360÷12=30 using information from the crank angle counter section 63 and an interrupt (gear interrupt) that occurs every time a crank angle signal is input.
It is recognized with an accuracy of (℃A). How to achieve the optimum energization timing and ignition timing calculated by the program will be explained for cylinders #1 and 4. The same explanation can be given for #2 and #3 cylinders. First, regarding energization, the optimum energization angle θ is decomposed as shown in the following equation. θ = θ ₁ + θ ₂ τ = τ (θ ₂ , N) (1) θ: Current conduction angle θ ₁ : Current conduction start crank angle that can be recognized by the CPU in 30℃A units (0 to 11 × 30℃A), that is, rotation angle Corresponding to each gear position of sensor 5 θ ₂ : Fraction below 30°C τ : Fraction below 30°C θ ₂ is converted into time in units of 8 μs based on the rotational speed N at that time. Then, in the gear interrupt that occurs at a gear position (θ ₁ -1) one position before the gear position θ ₁ calculated by the above formula, the CPU 60 issues a #1 and 4 coil energization command (terminal 453) as shown in FIG. 3c. ) and an energization down counter value set command (terminal 450). Further, by the pulse applied to the terminal 450, the contents of τ output from the CPU to the data bus 404 at the same time are set in the 16-bit energization down counters 900 and 901. 900,90
1 is an 8-bit down counter (for example, RCA
A 16-bit down counter is constructed by connecting them in series with CD40103B (manufactured by MITSUMI CORPORATION). This 16-bit down count value can have a value of 0 to 0.52428 seconds with an accuracy of 8 μs. Therefore, it is possible to down-count down to a rotation speed of about 3 rpm without overflow. When the flip-flop 909 is set, the output becomes "0" and the output of the NAND gate 910, that is, the D of the D-type flip-flop 911.
The input becomes "1". flipflop 911
Since the CK (clock) input is connected to the crank angle signal through the terminal 403, the flip-flop 911 is set at the next crank angle pulse after the #1 and #4 coil energization command and the energization down counter value set command are output. FIG. 3d shows the signal waveform of the Q output of flip-flop 911. When the flip-flop 911 is set, the output becomes "0", so the down counters 900 and 901
becomes capable of down-counting, and the reset input of the 4-bit frequency divider 925 is released, so that the down-counting clock is supplied to the CK inputs of the down counters 900 and 901, and down-counting is started.
The frequency divider 925 (for example, CD4520B manufactured by RCA) receives a 2 μs clock from the 4-bit down counter 202 of the timer section 62 through the terminal 455.
This frequency is divided by 4 to generate an 8 μs down count clock. real time timer 20
The reason why the 8 .mu.s clock is not used directly from the 7,208 is to ensure accuracy, especially when .tau.=0,1. Now, when the 16-bit down counters 900 and 901 finish counting down, the end signal is "0" and the down counter 90
Output from CO/ZD terminal of 0 and inverter 90
4, AND gate 906, NAND gate 907,
Through NAND gate 915, flip-flop 9
09, 911 (see FIG. 3d), and further passes through the inverter 914 to the down counter 90.
Since 0,901 is reset, the CO/ZD terminal returns to "1" again. Therefore, AND gate 90
6, that is, to the terminal 456, a pulse as shown in FIG. 3e is outputted. Also, since the Q output of the flip-flop 911 becomes "1", the down counters 900 and 901 stop counting, and the supply of the count down clock is also stopped.
Note that the down count clock inverted by the inverter 905 is applied to the other input of the AND gate 906.
The output becomes "1" with a delay of 4 μs from the down count end signal. This is to prevent malfunction due to a negative pulse (about 200 ns) that may occur at the CO/ZD terminal of the down count 900 immediately after the count down clock is applied.
The output pulse of AND gate 906 is applied through terminal 456 to AND gates 933 and 935 in FIG. Now, the output of flip-flop 909 in FIG. 11 is "1" until the R (reset) input is inverted to "1", and the output of flip-flop 909 in FIG.
Since the input of No. 3 is connected to the Q output of the flip-flop 909 through the terminal 457, the pulse applied to the terminal 456 is directly generated at the output of the AND gate 933, and the pulses applied to the #1 and #4 coils (coil B)
Control flip-flop 938 is set. When the Q output of flip-flop 938 changes to "1", the output of inverter buffer 939 becomes "0", so transistors 942 and 947 change to "1".
OFF, the transistor 952 turns ON, current flows between the input terminal of the first igniter 80 and the GND terminal 82, and the coils for the #1 and #4 cylinders start energizing. Note that diodes 948 and 953 are for transistor protection, and resistors 940, 941, 943 to 9
46,949 to 951,954 are solid resistors for damping ignition noise. Figure 11
One input of NAND gate 907 is frequency divider 925
It is connected to a terminal that supplies a 2 μs clock. Therefore, even if the output of the AND gate 906 changes to "1", the down counters 900, 9
01, flip-flops 909 and 911 are reset with a delay of 2 μs. This is to ensure the pulse width of the set pulse of flip-flop 938. Ignition angle (timing) θBX is also decomposed in the same way as equation (1). θBX = θBX ₁ + θBX ₂ τx = τx (θBX ₂ , N) θBX: Ignition angle of #1 and 4 coils (coil B) θBX ₁ : Ignition crank angle that can be recognized by the CPU in 30℃A units, (0 to 11× 30℃A) θBX ₂ : Fraction below 30℃ τx : Fraction below 30℃ A θBX ₂ is converted into time in units of 8 μs based on the rotational speed N at that time. Rotation sensor 5 that occurs when the engine crankshaft reaches the gear position (θBX ₁ -1) one position before the gear position (θBX ₁ ) calculated by equation (2)
When the gear interrupt occurs due to the rise of the crank angle signal 5b of the sensor 51, the CPU 60 outputs an ignition command (terminal 454, f in Figure 3) and sets τx in the 16-bit ignition down counters 902 and 903.When the crankshaft position is θBX ₁ When the count reaches , the flip-flop 922 is set.The 16-bit down counters 902 and 903 start counting down with an 8 μs clock, and at the same time as the down counting ends, a positive pulse as shown in FIG. 3h is generated at the terminal 459. .Figure 3g is a flip-flop

【table】

[Table] Each program process will be explained in sequence below. FIG. 13 shows a flowchart of the gear interrupt processing routine. Gear interrupts have the highest priority and are processed with the highest priority. Activation of this gear interrupt is performed by the interrupt control unit 6 shown in FIG.
This is done by a crank angle pulse from terminal 444 of 1. Therefore, a gear interrupt occurs every 30 degrees of crank angle, with the top dead center position of #1 cylinder or #4 cylinder being 0 degrees. When activated, the gear interrupt is reset in step 1100 (resetting the flip-flop 302 in FIG. 6), and the crank angle counter section 6 shown in FIG. 4 is reset in step 1200.
3, the CPU 60 reads the current crank position and learns the rotational angular position of the engine. Step 1
In the energization ignition process 300, data is set in the energization ignition control section 68 to perform energization ignition control in accordance with energization ignition control data calculated at step 2140 of the program interrupt described later. Next step 1
In the fixed position processing 400, processing is performed at a determined fixed crank position. FIG. 14 shows a detailed flowchart of the energization ignition processing step 1300. In step 1305, of the two ignition coils, the angle at which to start the down count for starting energization of coil A, determined in step 2140 of the program interrupt described later, is compared with the current crank angle position determined in step 1200, and it is determined that they match. If so, in step 1310 the first
At the same time as setting an initial value to the down counter 900 for energizing coil A shown in FIG. 1, a command for energizing coil A is output. This down counter counts down with a clock signal of 8 .mu.sec, and when it reaches "0", the energization signal of the coil A is set to "0" to start energization. In step 1315, the angle at which to start counting down for ignition of coil A and step 1 are determined.
The current crank angle position determined in step 200 is compared, and if they match, the 11th position is determined in step 1320.
At the same time as the initial value is set in the coil A ignition down counter 902 shown in the figure, a coil A ignition command is output. This down counter 902 counts down with an 8 μsec clock signal and when it reaches "0", stopping the energization of the ignition coil corresponds to ignition, so the coil A energization signal is set to logic "1" and the coil A energization is stopped. Note that steps 1325, 1330, and 13 are also performed for coil B.
35, 1340, energization ignition control is similarly performed. Next, FIG. 15 shows at which rotational angular position the fixed position processing step 1400 is performed. In contrast to the angular position at which the process is effectively performed in the energization ignition processing step 1300, which varies depending on the value calculated at the program interrupt, the fixed position processing step 14
00, processing is performed at a predetermined angular position. At crank angles of 0 degrees and 180 degrees, measure the rotation time required to rotate the crank angle 180 degrees, measure the intake pipe pressure, and generate a program interrupt, and at other angles, complete the process without doing anything. . To explain this process in detail, the rotation angle is determined in step 1410, and when it is 0 degrees or 180 degrees, the rotation angle is determined in step 141.
Proceed to step 1 and measure the 180 degree rotation time. In step 1411, the real-time timer value latched using the timer section 62 in _FIG .
Tm=Tp ₂ −Tp ₁ ...(3). Step 1
In step 413, the value of Tp ₂ is transferred to Tp ₁ . In step 1414, an A/D converted value of intake pipe pressure is taken in order to prevent intake pulsation. Also, step 141
5, the program interrupt output port of the digital input/output port 64 is set to level "0" and then set to level "1" again to generate a program interrupt signal and start a program interrupt processing routine. Next, FIG. 16 shows a program interrupt processing routine. First, in step 2100, a reset signal is applied to the terminal 442 of the interrupt control section 61 shown in FIG. 6 to reset the flip-flop 301.
The program interrupt request signal terminal 445 is returned to "1". Next, the process advances to step 2111, where the 180 degree rotation time stopped in the gear interrupt processing routine is
Convert to rotation speed N using equation (4). N (rpm) = 10 ⁷ × 3 / Tm (μs) ... (4) In step 2112, the A/D conversion value Vpm of the intake pipe pressure taken in at crank angles of 0 degrees and 180 degrees in the gear interrupt processing routine is calculated. Using formula (5), intake pipe pressure Pm (in mmHg) Pm = A ₁ × Vpm + A ₂ ... (5) A ₁ , A ₂ : Convert to conversion coefficient. In step 2120, the signal from the starter switch 31 shown in FIG. conduct. If the starter is not operating, the process proceeds to step 2130 to obtain the final ignition timing θx, and similarly proceeds to step 214.
0, the output value to the energization ignition timing control section 68 is calculated. Here, FIG. 17 shows the relationship between the ignition timing and engine speed at a certain accelerator opening degree. Ignition timing is expressed as the angle before top dead center (・BTDC), and the larger the value, the more advanced it is. The accelerator opening degree α ₁ indicates a state close to the fully open accelerator, and θ _M1 is the optimum ignition timing (MBT) that maximizes the engine output at the accelerator opening degree α ₁ . This optimal ignition timing is the best in terms of torque and fuel consumption. α ₂
is a graph when the accelerator opening is small. FIG. 18 shows a two-dimensional map (MBT advance angle map;
Tmap) has the following configuration. The horizontal axis is the engine speed N, and in the low speed range below 1000r.pm, the increment of the engine speed N is small with respect to the column number I haven't gotten used to it. The vertical axis of Tmap is the intake pipe pressure Pm, which is proportional to the row number Y corresponding to the vertical axis. This Tmap is constantly rewritten by the feedback learning process described below.
The ignition timing is the lowest for fuel consumption from maximum torque. First, the details of the ignition timing calculation in step 2130 will be explained with reference to FIG. Step 2131
Now convert from rotation speed N to column number X according to equation (6). Here, Nxi is the maximum rotation number specified on the map horizontal axis that does not exceed N, Xi is an integer column number corresponding to Nxi, and the decimal point part of Indicates the number of rotations. Further, in step 2132, the intake pipe pressure Pm is converted into the row number Y according to equation (7). Here, Pm _Y i is the intake pipe pressure specified on the maximum vertical axis of the map that does not exceed Pm, Yi is the line number corresponding to Pm _Y i and is an integer, Y
The decimal point indicates the pressure in the middle of the intake pipe pressure specified on the vertical axis of the map. In step 2133, MBT is set corresponding to X and Y.
Find the MBT advance angle θmap from the advance angle map (Tmap) by interpolating four points using equation (8). In step 2134, the delay in the ignition signal caused by the igniter or the like is converted into a crank angle, which is defined as the ignition delay angle (θ _DLY ). The relational expression is as shown in equation (9). θ _DLY = t _DLY × 180 (degrees CA) / Tm (μs) (9) t _DLY : Delay time of ignition signal by igniter (40 to 100 μs) Tm: 180 degree rotation time (μs) Next, in step 2135, MBT feedback is Take control. First, control of MBT feedback will be explained. In this example, optimum ignition timing (MBT)
If the vehicle is operated in the vicinity of
Point ignition timing (base, advance, retard)
The engine speed is compared to control the engine speed to bring it closer to the optimal ignition timing. Here, among the three ignition timing points, the base is the ignition timing determined in step 2133, and the ignition timing has a difference of Δθ (usually 2° to 3°).
Advance is when the angle is advanced by ゜), and retard is when it is retarded by Δθ. The use of base, advance, retard, and lead angle values is called dither. At each of these three points, the rotation speed when operating at a constant ignition (for example, 40 to 60 ignitions) is N _B
Let _A , _NAD , _NRT (expressed in number of clock pulses). That is, a/N _BA , a/N _AD , a/
N _RT (a is a constant) is the rotation speed. For example, the second
When the target ignition timing θ ₀ is on the retarded side of the optimum ignition timing (MBT) that can maximize the engine torque, as in state I in Figure 0, N _AD <N _BA.
<N _RT holds true, and it becomes necessary to control the ignition timing toward the advance side. Also, like the state
When existing on the advance side of MBT, N _RT <N _BA
<N _AD Since the relationship holds true, it becomes necessary to control to the retarded side. One cycle of base ignition timing, advance ignition timing, and retard ignition timing each having a fixed number of ignitions is one feedback cycle. A part of the MBT advance angle map in Figure 18 is shown in Figure 21.
As shown in the figure. For example, a certain operating condition (2000r.pm,
400mmHg) point rotation speed from 1750r.pm to 2250r.pm, intake pipe pressure
Defined as 377.5mmHg to 422.5mmHg. In this embodiment, it is assumed that the operating state during one feedback period begins at point A and ends at point B. During this time, eight feedback areas (revolutions
1250r.pm to 2750r.pm, intake pipe pressure
If there is a change in operating conditions within the range of 332.5mmHg to 467.5mmHg), it is considered steady. In addition, if the operating state (point C) deviates from the feedback area even once, it is determined to be unsteady. , intake pipe pressure
232.5mmHg to 377.5mmHg) is the new steady range and the control is restarted from the beginning (base). If the operating condition is steady during one feedback cycle,
The feedback area that is operated the most (most frequently used) is calculated, and the ignition timing of these eight areas is advanced or retarded to be corrected during feedback, which will be described later. Also, if the frequency of use of the most frequently operated feedback area is not greater than 60% in one feedback cycle, no correction will be made.
The optimum ignition timing for the maximum shaft output of a certain engine with respect to the rotational speed and intake pipe pressure has the characteristics as shown in Fig. 22, and there are 8 points around the ignition timing of the determined representative point E (for example, 2000r in Fig. 23). pm, 400mmHg
Assuming that is the representative point, a ₁ (1500r.pm, 355mmHg), a ₂ (1500r.p,
m, 400mmHg), A ₃ (1500r.pm), A ₄ (2000r.p.
m, 355mmHg), a ₅ (2000r.pm, 445mmHg),
a ₆ (2500r.pm, 355mmHg), a ₇ (2500r.pm,
400mmHg), a ₈ (2500r.pm, 445mmHg) 8 each
point} is modified and brought closer using equation (10). In this way, the ignition timing for each operating state can be quickly corrected to the optimum value. In addition, in the idle range, misfires may occur if the ignition timing is controlled to the optimal level, and in the high load range, knocking may occur, which may have a negative effect on the engine, or the knocking noise may cause noise to the driver and make him or her feel uncomfortable. , feedback control is not performed in these areas. Next, a detailed explanation of step 2135 of MBT feedback in FIG. 19 is shown in FIG. In step 2141, the column number X corresponding to the rotational speed N and the intake pipe pressure are used to determine which feedback area corresponds to the map in FIG. 18, as explained in FIG. 21.
Calculate the line number Y corresponding to Pm. Step 2
142, step 42 of the main routine, which will be described later.
If the water temperature determined by 00 is higher than 70°C, proceed to step 2143; if it is low, proceed to step 2180. In step 2143, it is determined whether the area of the map determined in step 2141 is within the feedback range. For example, if the advance angle is set to match MBT, it may cause a misfire in the idle range, and in the high load range, the engine may enter the knock zone and have a negative impact on the engine. In order to prevent this, first
Prepare a feedback judgment table with the same increments as the map in Figure 8, and set the areas for feedback to 0 and the areas for non-feedback to a number other than 0. Feedback will be performed in areas with 0, and feedback will be stopped in areas that are not 0. controlled to do so. In step 2143, it is determined whether or not the X and Y areas found in step 2141 are feedback areas. If they are, the process branches to step 2144, and if not, the process branches to step 2180. Step 2144 is a step for determining whether the state is stationary or unsteady as described above. If it is determined that it is within the steady range as explained in FIG. 21, steps 2145 to 2148 are skipped and the process moves to step 2149. If it is determined to be unsteady, steps 2145 to 214 are performed.
It is initialized to 8. In step 2145, the values of column number X and row number Y at that time are transferred to Xi and Yi, respectively. From next time onwards, Xi and Yi will play a central role in determining whether the situation is steady or unsteady. In step 2146, the number of ignitions is counted. Counter _n1 is set to 0, and in step 2147, the dither flag F _DSR is set.
F _DSR = -1, dither advance angle θ _DSR is 0° CA
(θ _DSR = 0), and control starts again from the base ignition timing. In step 2148, the timer count values N _BA , N _AD , and N _RT for base, advance, and retard are set to 0, respectively.
Next, in step 2149, step 2, which will be described later, is executed.
In order to detect the most frequently used region of the two-dimensional map during one feedback period at step 190,
Count the number of times X and Y are used.
Counting is around 8 around Xi and Yi.
Area {(Xi− ₁ , Yi− ₁ ), (Xi− ₁ , Yi), (Xi−
₁ , Yi+ ₁ ), (Xi, Yi- ₁ ), (Xi, Yi+ ₁ ),
(Xi+ ₁ , Yi− ₁ ), (Xi+ ₁ , Yi), (Xi+ ₁ , Yi
+ ₁ )}. In steps 2180 to 2182, which are branched from steps 2142 and 2143, initialization is performed based on control, as in steps 2146 to 2148. Then, this MBT feedback processing is ended without performing any feedback. Next, steps after step 2149 are shown in FIG.
In step 2150, it is determined whether the current state is base, advance, or retard, and the clock pulses in each state are counted. First, when F _DSR =-1, that is, base, the process goes to step 2151; when F _DSR = 0, that is, advance, go to step ₂₁₆₁ ;
1, that is, when it is in retard, step 2171
Proceed to. First, the base from step 2151 will be explained. Add the 180° rotation time Tm and the base K ignition timer count value N _BA to N _BA . In step 2152, the dither advance angle is set to 0°.
Set CA (θ _DSR = 0) and step 2153
The counter counts up until the specified number of ignitions K is reached. In other words, the formula n ₁ =n ₁ +1 is executed. This is for K ignitions (for example, 40 to 60 ignitions)
repeat. In step 2154, n ₁ =K, that is,
Once the clock pulses for K ignitions have been counted, the counter value is returned to 0 in step 2155, and in step 2156, F _DSR is set to 0 (advance) in order to transfer control to the next advance, and the dither advance angle θ _DSR is set. In order to advance the angle by Δθ, set θ _DSR =Δθ. In other cases, steps 2155 and 2156 are skipped. If it is determined in step 2150 that F _DSR =0, the process advances to step 2161. Step 216
In step 1, as in step 2151, the 180° rotation time Tm is added to the advance K ignition timer count value N _AD and set to N _AD again. Step 2162
Now, in order to advance the dither advance angle by Δθ, θ _DS
Set _R = △θ. In step 2163, as in step 2153, _n1 is counted up,
In step 2164, it is determined whether n ₁ =K, that is, clock pulses for K ignitions have been counted.
In step 2165, the counter value is returned to 0.
In step 2166, F _DSR is set to 1 (retard) in order to transfer control to the next retard state, and θ _DSR =-Δθ is set to retard the dither advance angle θ _DSR by Δθ. In other cases, the processing in steps 2165 and 2166 is skipped. If the retard is F _DSR =1 in step 2150, the process advances to step 2171. In step 2171, as in step 2151, the 180° rotation time Tm
is added to the retard K ignition timer count value N _RT and set as N _RT . In step 2172, θ _DSR =-Δθ is set to retard the dither advance angle by Δθ. In step 2173, step 21
63, count up _n1 . If n ₁ =K, that is, clock pulses for K ignitions have been counted in step 2174, the counter value is returned to 0 in step 2175. Step 2176
Now, in order to transfer control to the next base state, F _DSR
= -1 (base) and dither advance angle θ
_DSR is also set to 0. At other times, step 2
Processes 175 and 2176 are skipped. The process then proceeds to step 2190 in FIG. 26, and calculates the area of the two-dimensional map that is most frequently used in one feedback cycle (base, advance, retard) based on step 2149, and sets the column number to X _M . Let the line number be _YM . Step 219
In step 1, it is determined whether this most frequently used area exists for, for example, 60% or more of one feedback cycle, and if it does exist, the process advances to step 2192.
If it is less than 60%, proceed to step 2198 and do not make any corrections. For example, as in state I in Fig. 20, when the ignition timing is on the retarded side of the optimum ignition timing that can maximize the torque in the engine state at that time, and when there is no change in the engine operating state, As described above, when ignition is first performed with dither advance angle θ _DSR = 0, the number of revolutions per K ignition number is a/N _BA (where a is a constant), and then the ignition timing on the advance side from the base is The rotation speed when ignited at θ _DSR = Δθ is a/N _A
D , then the retard side ignition timing θ _DSR = -Δ
The rotation speed when igniting at θ is a/N _RT , and comparing the rotation speeds, a/N _RT < a/N _BA < a/N _AD
In other words, N _AD < N _BA < N _RT . Therefore, N _AD <N
When the relationship _BA <N _RT is established, this is determined in step 2192, and the process proceeds to step 2193, where the corrected advance angle T=ΔT (for example, 1° to 2° C.A.) is established. Note that if N _AD <N _BA <N _RT does not hold, the process advances to step 2194. For example, when the ignition timing is advanced from the optimum ignition timing that can maximize torque, as in the situation shown in Fig. 20, conversely, a/N _AD < a/N _BA < a/N _RT , that is, N _RT ＜N
_BA < N _AD . Therefore, when N _RT <N _BA <N _AD is established, it is determined in step 2194 and the process proceeds to step 2195, where the corrected advance angle T is set to -ΔT.
If the relationships N _AD < N _BA < N _RT and N _RT < N _BA < N _AD do not hold, the process advances to step 2198 and no correction is made. N _AD <N _BA <N _RT or N _RT <N _BA <
When the relationship N _AD is established, step 2196
Then, the X _M and Y _M lead angle values of the most frequently used map area obtained in step 2190 are set as N.
When _AD <N _BA <N _RT , advance the angle by ΔT, and when N _RT <N _BA
<N _AD, as shown in Figure 18, to retard ΔT.
Rewrite Tmap. In step 2197, _eight points around this area (points _a1 to a in FIG. 23) are corrected as follows. Amount of correction for a ₁ ΔT ₁ =0.15×ΔT a ₂ 〃 ΔT ₂ =0.10×ΔT a ₃ 〃 ΔT ₃ =0.05×ΔT a ₄ 〃 ΔT ₄ =0.20×ΔT a ₅ 〃 ΔT ₅ =0.10×ΔT a ₆ 〃 ΔT ₆ =0.40×ΔT a ₇ 〃 ΔT ₇ =0.20×ΔT a ₈ 〃 ΔT ₈ =0.15×ΔT Next, in step 2198, each clock pulse number (N _BA , N _AD , N _RT ) is set to 0. This completes the MBT feedback calculation in step 2135 in FIG. And step 2 in Figure 19
At step 136, the final ignition timing θx is calculated using equation (11). θx = θmap + θ _DLY + θ _DSR ...(11) The calculation of the ignition timing is completed above, and in step 2140 of Fig. 16, the coil energization time _T Calculate the energization angle. Also, find the energization start angle θ _ON from the final ignition timing θx,
For the coils A and B, a down count value of the energization start crank angle and a down count value of the ignition crank angle are determined and used for the energization and ignition processing in step 1300 of the gear interrupt routine described above.
The steps when the starter is activated are also processed in a similar manner. This completes the program interrupt processing. FIG. 27 shows a flowchart of the 8ms interrupt processing routine. At step 3100, a reset signal is applied to the terminal 443 of the interrupt control section 61 shown in FIG. 6 to reset the flip-flop 300.
Return the 8ms interrupt request signal terminal 446 to "1". In step 3110, analog input port 6
5, and calculate the coil energization time T _ON using the energization time characteristics shown in FIG. 29. FIG. 28 shows a flowchart of the main routine. In step 4100, initialization processing is performed.
Clears the RAM area, inputs various initial parameters, and enables interrupts. Step 4200 is a process of calculating an A/D converted value of water temperature. This step is executed whenever there is no interrupt processing. As explained in detail above, the present invention identifies whether the rotational speed, torque, etc. have changed due to external factors, or whether the rotational speed, torque, etc. have changed due to changes in the ignition timing at at least two different points. This has the excellent effect of correcting the target ignition timing to the optimum ignition timing, maximizing engine output, and minimizing fuel consumption. Furthermore, if the most frequently used area of the 2D map is used more than a predetermined percentage, the most frequently used area or its vicinity is corrected, so the 2D map's used area can be expanded over a wide range. This has an excellent effect in that the two-dimensional map can be corrected with high precision even if the map is jagged. Furthermore, according to the present invention, when the values used in the two-dimensional map deviate from a predetermined area, detection of signals such as rotation speed and torque is interrupted, and new detection is started from the deviated area. This has the excellent effect of preventing erroneous corrections during engine transient conditions.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a control system showing an embodiment of the present invention, Fig. 2 is a block diagram of a control computer in Fig. 1, and Figs. 3 and 8 are diagrams for explaining each part of Fig. 2. The waveform diagrams, Figures 4 to 7, and Figures 9 to 12 are electrical circuit diagrams of various parts in Figure 2, and Figure 1.
Figures 3 to 16, Figure 19, Figure 24 to 2
Figure 8 is a flowchart showing the arithmetic processing procedure of the control computer shown in Figure 1, Figures 17 and 20.
22 and 29 are characteristic diagrams for explaining the operation of the present invention, and FIGS. 18, 21, and 23 are two-dimensional map schematic diagrams for explaining the operation of the present invention. 1... Engine, 2... Water temperature sensor, 3... Starter, 4... Ignition coil, 5... Rotation sensor,
6...Control computer, 7...Igniter, 8
...Pressure sensor, 60 ...Central processing unit, 7
1...Nonvolatile RAM that makes up a two-dimensional map.

Claims (1)

[Claims] 1. Construct a two-dimensional map for calculating the target ignition timing based on two states of the engine, a first operating state and a second operating state, and at least two points near the target ignition timing and different from each other. select an ignition timing, operate the engine alternately for a predetermined period at at least two selected ignition timings, and generate a signal of the engine rotational speed when operating at each of these ignition timings;
Torque signals or operating state signals related thereto are detected, and at least three of the operating state signals when operating at the at least two ignition timing points are operated continuously. By comparing the signals, it is determined whether the target ignition timing is ahead or behind the optimal ignition timing that maximizes the engine output, and the value of the two-dimensional map is determined according to the result of this determination. An ignition timing control method characterized by correcting. 2. The value of the two-dimensional map is corrected when the frequency of use of the most frequently used area of the two-dimensional map is at least a predetermined percentage during the period for determining whether the ignition timing is at the optimum ignition timing. In this case, the above 2
2. The ignition timing control method according to claim 1, wherein the most frequently used region of the dimensional map or its vicinity is corrected. 3. According to claim 2, the amount of correction in the vicinity of the most frequently used area in the two-dimensional map is smaller than that of the most frequently used area and is not uniform. ignition timing control method. 4. Constructing a two-dimensional map for calculating a target ignition timing based on two states, a first operating state and a second operating state, of the engine, and selecting at least two ignition timing points near the target ignition timing and different from each other; The engine is operated alternately for a predetermined period at the selected at least two ignition timing points, and the engine rotation speed signal, torque signal, or operating state related to these when the engine is operated at each of these ignition timing points. The target ignition timing is determined by detecting a signal of the operating state at at least three consecutive points among the signals of the operating state when operating at the at least two points of ignition timing. It is determined whether the ignition timing is on the advanced or delayed side of the optimal ignition timing that maximizes the engine output, and the most When the frequency of use of the frequently used area is equal to or higher than a predetermined ratio, the most frequently used area of the two-dimensional map or its vicinity is modified, and the target ignition timing and at least two ignition timings are further adjusted. An ignition timing control method characterized in that when the corresponding value of the two-dimensional map deviates from a predetermined range, detection of the operating state signal is interrupted and new detection is started from the deviated range.