JPS61244870A - Ignition timing control device for internal-combustion engine - Google Patents

Abstract

PURPOSE:To provide an internal-combustion engine having high efficiency, by a method wherein torque is controlled to a maximum value under a state in that no knock occurs. CONSTITUTION:A CPU 12 inputs signals from various sensors, e.g., an inner pressure detecting device 30, a crank angle sensor 40, a load sensor 50, through an input output interface circuit 20. Based on the signals, an ignition timing is calculated according to a program stored in a ROM 14, and an ignition signal IGN is outputted through the input output interface circuit 20. By means of the ignition signal IGN, a power transistor 74 is driven and an ignition current is generated to the secondary coil of an ignition coil 76. An igniton timing is controlled so that a crank angle (an angle from a top dead centre), at which a pressure in a cylinder right before production of knock shows a peak, is stored, and in following crank angles, a crank angle, at which the pressure in the cylinder indicates a peak, is adjusted to a crank angle stored.

Description

Detailed Description of the Invention [Field of Application of the Invention] The present invention relates to an ignition timing control system for an internal combustion engine.
The present invention relates to an ignition timing control device for an internal combustion engine that detects cylinder pressure and controls a function related to torque to a maximum value.

[Background of the invention]

A basic system for controlling the ignition timing of an internal combustion engine by detecting the cylinder pressure is disclosed in Japanese Patent Laid-Open No. 47-4903 and Japanese Patent Laid-Open No. 53-56429.

Although these control the ignition timing based on internal pressure, they have not reached the level of controlling the torque of the internal combustion engine.

Although the cylinder pressure does not represent the torque itself, it represents a function related to torque, and the cylinder pressure can be used to control the torque.

By controlling the torque to the maximum value when no knock occurs, a highly efficient internal combustion engine can be provided, and
Drivability can also be improved.

[Purpose of the invention]

An object of the present invention is to provide an ignition timing control device that can improve the efficiency of an internal combustion engine.

[Summary of the invention]

The output of the cylinder pressure detection sensor is input, and the output of the mixer circuit is used as the knock detection circuit and the cylinder pressure detection circuit.
Divide into systems. The ignition timing of an internal combustion engine is advanced at a specific timing, and the pressure inside the cylinder is taken in at a specific timing. (For example, the cylinder pressure is A/D converted at a fixed angle from top dead center.) When the ignition timing is advanced, the peak of the cylinder pressure also moves toward the top dead center side, and the ignition timing is further advanced. and knocking occurs. If knocking occurs, the previous ignition timing is used without advancing the ignition timing. Store the crank angle (angle from top dead center) at which the cylinder pressure peaks just before knocking occurs.

From the next cycle onwards, the ignition timing is controlled so that the crank angle at which the cylinder pressure peaks becomes the stored crank angle. Cylinder internal pressure does not directly represent torque, but it shows a function related to torque, and by controlling the internal pressure to the angle that has the maximum value just before knocking occurs, the cylinder pressure is controlled to the angle where the torque is highest. It is possible to increase the efficiency of internal combustion engines.

[Embodiments of the invention]

Examples of the present invention will be described below.

FIG. 1 shows an ignition timing control section of an internal combustion engine control device to which the present invention is applied. The Centra Processing Unit (hereinafter referred to as CPU) K performs digital calculation processing of various data including the ignition timing of the internal combustion engine. ROMI It stores ignition timing control and other control programs and fixed data. The RAM 16 is a readable and writable storage element. Backup R, AM17
R and AM retain their memory even when the Fi internal combustion engine is stopped.

The CPU 2 connects various sensors (in this embodiment, a knocking detection device 30
．． Crank angle sensor 40. A load sensor 50 is used. ), and based on this signal, I'
(The ignition timing is calculated according to the program stored in the 0M14, and the ignition signal IGN is outputted via the input/output interface circuit 20.

The ignition signal IGN is applied to the base of the power transistor 74 via an amplifier 72, and
to drive. By shutting off the power transistor 74, an ignition current is generated in the secondary coil of the ignition coil 76.

FIG. 2 shows a specific configuration of a portion of the input/output interface circuit 20vC that contributes to ignition timing control. A position pulse signal (denoted as POS) from crank angle sensor 40 is applied to 771 circuits 216 and 220. Further, the reference crank angle signal (denoted as R, EF) from the crank angle sensor 40 is sent to the first counter register 21.
0 reset terminal and the set terminal of R8 flip-flop 218. First counter register 21
0 key AND circuit 216 and RS flip 70 knob 21
8, POS counting is started based on the rise of REF, and the counted value is output to the comparator 206. The comparator 206 compares the count value of the 10th counter register with the ignition timing data θ,1 calculated by the CPU 12 and stored in the advance register 202, and when the two match, R87! The BS flip-flop 218 is reset at the same time as the J flip-flop 214 is output from the Vc set pulse. When a set pulse is input to the BS flip-flop 214, the Q output is cut off, the power transistor 74 of the ignition system is cut off, and a discharge current is output to the secondary coil of the ignition coil 76.

Next, the timing of starting energization of the ignition coil will be explained. Second
counter register 212I/'i, comparator 2
R8 flip-flop 22 determined by Q6Vc
Based on the set pulse for turning on PO2, counting of position pulses PO8 is started via the AND circuit 220, and the counted value is output to the comparator 208. The comparator 208 compares this count value with the value calculated by the CPU 12Vc and stored in the dwell register 204,
When the two match, a reset pulse is output to the R,8 flip-flop 214 and the BS flip-flop 2 is output.
Reset 22. The RS flip-flop 214 generates an output at the Q terminal based on the reset pulse, turns on the power transistor 74, and turns one of the ignition coils 76 on.
Start energizing the next coil.

Next, the introduction of the knocking signal KNCKP to the CPUI 2 will be explained.

The output pulses KNCKP of the internal pressure detection device 30 are input to a counter register 234, and the number of KNCKPs is counted in proportion to the intensity of knocking that has occurred.

The CPU 12 registers the counter register 23 with a rotation synchronization interrupt.
The count value of 4 is input to the CPU 12 via the path 18, and the count value of the counter register 234 is cleared by the reset register 238 in preparation for the next occurrence of knocking. The number of pulses NF taken into the CPU 12 is
This data corresponds to the intensity of knocking and is used to calculate ignition timing correction.

FIG. 3 is a timing chart showing the operation of the circuit shown in FIG. 2 described above. In the figure, A is a reference crank angle signal and B is a position pulse signal. C indicates the counting status of the first counter register 210, and C1 is the setting value of the advance register 202. D indicates the output signal of the comparator 206, and indicates that an output is generated when the count value of the first counter register 210 reaches the setting [of the advance register 202].

E indicates the counting status of the 20th counter register 212, and El is the set value of the dwell register 204. Ft
ri, the output of the comparator 208, the comparator 20
The operation is similar to No. 6. G is the comparator 206,2
08, that is, the Q output of the R, S flip-flop 214 in response to the D, F. H indicates the current flowing through the ignition coil 66 in response to this calculated power, and H indicates the ignition timing.

FIG. 4 shows a block diagram of a cylinder pressure detection circuit 30 that responds to cylinder pressure and detects cylinder pressure peaks and knocking.

In the figure, cylinder internal pressure sensors 401 to 404 are installed in the engine/engine for each cylinder (the block diagram in Figure 4 shows an example of a four-cylinder engine), and are connected to a mixer 412 through amplifier circuits 405 to 408. is input to. The output of mixer 412 is separated into two systems. One system is input to a half-wave rectifier circuit 414 through a 4 (D"t' band-pass filter 413) which extracts a signal superimposed on the cylinder internal pressure sensor when a knock occurs. Output Fi2 system of the half-wave rectifier circuit 414 One is for creating a reference voltage for comparison, and includes a smoothing circuit 415 and an amplifier circuit 416.
The signal is input to one side of the comparator 4090 through.

The other side of the half-wave rectifier circuit 414 is input to the other side of the comparator 409 through the amplifier circuit 417. Comparator 40
9, the signals of the amplifiers 416 and 417 are compared, and the output of the comparator 409 is input to Ilo, where the number of pulses when knocking occurs is counted.

The other output of the mixer 412 is a low pass filter 418,
The signal is input through the amplifier circuit 419 to the A/D converter of Ilo. The output of the amplifier 419 is for detecting the peak of the cylinder pressure, and is 2/.

The A/D converter captures the data at specific timing and for a specific period (for example, at a constant crank angle).

FIG. 5 VC shows a waveform diagram of the block diagram shown in FIG. 4. Figure 1M5 shows the output of the mixer 412 and shows the peak of the cylinder pressure for each cylinder. Knock has occurred in the cylinder C in Figure 5, and the output waveform of the amplifier 417 in Figure 4 and the output waveform of the water amplifier 419 in Figure 4 are shown.

Top Dead Center (TDC)
The output of the amplifier 419 is taken in at a constant crank angle Δθ. (In this embodiment, the output of the internal pressure sensor is taken from top dead center, but it may be taken from 10 degrees after top dead center.) In the example of Fig. 6, θ4 crank angle θ is the peak of the internal pressure waveform. corresponds to

7 and 8 show circuit diagrams corresponding to the water amplifiers 405-408 and mixer 412 in FIG. 4.

Figure 7 shows an example using a positive phase amplifier (buffer with amplification factor 1), with resistors 501 to 512, capacitor 521,
522, 523, 524, operational amplifier 529, 530,
Amplifiers 405 to 408-1 at 531 and 532! It's hugely structured. Resistors 513 to 520, capacitor 525,
526, 527° 528, mixer 4 with operational amplifier 533
12 is ripe for composition.

Figure '8' shows an example using an inverting amplifier. amplifier 40
5 to 408, resistor 551 to 562, capacitor 569
, 570, 571, 572, operational amplifier 577, ri 78
, 579, 580. The mixer 412 is
Resistors 563-568, capacitors 573, 574, 57
5,576 and an operational amplifier 581.

FIG. 9 shows the general flow of the ignition timing control device in this embodiment. In the figure, when an interrupt request 600 occurs, the interrupt request analysis process in step 602 determines whether it is an angle (ANOLE), a reference (R, EF), etc.
) The timer interrupt (TIMER) is determined. In the case of a timer interrupt (TIMER), the VC performs A/D conversion of the input signal (excluding A/D conversion of the internal pressure sensor output), input 606 of engine speed, ignition timing, and Calculation of total time 608
Each task of digital input signal processing 610 and correction processing 612 is executed.

As a result of the interrupt request analysis in step 602, if it is a constant angle interrupt request, an angle processing routine is executed in step 615. In step 620 shown in FIG. 10, A/D conversion of the cylinder internal pressure is performed, and in step 621, the A/D converted value is converted to R and AM. In step 622, the angle for performing the next angle interruption is updated. In step 623, it is determined whether or not the A/D conversion of the cylinder internal pressure has been completed.If the constant angle interrupt is performed up to 04 in FIG. (Angle interrupt prohibition) is performed.

Further, as a result of the interrupt request analysis process in step 602, if the interrupt request is based on a reference signal, step 616
A rotation synchronization processing routine is executed in .

FIG. 11 shows the rotation synchronization processing routine. In step 701, the peak of the cylinder pressure is searched from the A/D conversion value of the cylinder pressure stored in the constant angle interrupt step 621, and in step 702, the crank angle at this time is determined by R, AM (random access).・In step 703, the peak value of the cylinder internal pressure is stored. In step 704, CNTR23
4Vc Read the number of knock pulses taken in. Step 7
In step 05, it is determined whether or not knock control is currently being performed. If a report that knock control is in progress (flag set) has been made, the process advances to step 712 and knock control is performed. Step 70
If knock control is not in progress at step 5, the process advances to step 706.

In step 706, it is determined whether the current mode is a mode (check mode) in which the ignition timing is advanced and the peak of the cylinder pressure is maximized in a state where no knocking occurs. If it is the check mode in step 706, the process advances to step 707. In step 707,
In step 704, it is determined whether the number N of knock pulses taken in is equal to or higher than the knock detection level Ns. Step 7
If the number N of knock pulses is equal to or less than the knock detection pulse N8 in step 07, the process advances to step 713.

In step 713, the current peak value of the cylinder internal pressure is compared with the maximum value of the cylinder internal pressure up to the previous time, and if the current peak value is larger as a result of the comparison, step 714
- Proceed to \, otherwise proceed to step 715. In step 714, the maximum value of the peak value of the cylinder internal pressure and the crank angle at that time are stored. In step 715, the ignition timing is advanced. In other words, in the check mode, the ignition timing is advanced until knock occurs (N in step 707, >N@), and the maximum value of the cylinder pressure peak during that time and the crank position at which the cylinder pressure peak is maximum. Store angle. Proceed to step 722.

If the knocking pulse N is equal to or greater than the number of knock detection pulses N8 in step 707, it is determined that knocking has occurred in the engine, and the process proceeds to step 708. Step 708
Now, because knocking occurred as a result of advancing the ignition timing, reset the check mode. Step 709
Now, set the maximum value of the ignition timing to the ignition timing immediately before the knock occurs. In step 710, the crank angle at which the peak of the cylinder pressure is maximum is set as θT. In step 711, a knock report is made.

In step 712, knock control is performed. Step 722
Proceed to.

If it is not the check mode in step 706, the process advances to step 716. In step 716, 0T set in step 710 multiplied by Kl (coefficient) is compared with the crank angle θ, which indicates the peak of the cylinder pressure taken in step 702. (K, <1) 1θ at step 716! If θ, step 718
If not, proceed to step 717. In step 717, the ignition timing is delayed because the crank angle is too advanced. Proceed to step 720. Step 718
If θ<K, θ〒, the process proceeds to step 720; otherwise, the process proceeds to step 719. (Kt>1) In step 719, the ignition timing is advanced. In step 720, the ignition timing is set to the maximum value (ignition timing immediately before knocking occurs).
Determine if it does not exceed. Maximum ignition timing ADV
If it exceeds max, the ignition timing is set to ADVm in step 721.
Make it ax. Otherwise, proceed to step 722.

In step 722, a comparison is made to update the counter and move to check mode at a specific timing. If the comparison result is N1 or more in step 722, step 723
The counter is set and the check mode is set. In this embodiment, the mode is changed to the check mode according to the number of rotation synchronization processing routines, but the mode may be changed to the check mode at a specific time.

Also, knock detection pulse number Ns + maximum value A of ignition timing
D Vmax + crank angle θ↑ and the peak value of the cylinder internal pressure are a map of rotation speed and load.

As mentioned above, there are 6 modes in 1 check mode.

The crank angle 0 is determined at which the peak of the cylinder pressure immediately before the cylinder pressure occurs is the maximum value, and after that, the crank angle θ, which indicates the peak of the cylinder pressure, is controlled so that the crank angle is θ, θ, θ, θ, and θ. be done.

Although the cylinder pressure does not represent the torque itself, it represents a function related to the torque.

〔Effect of the invention〕

As explained above, according to the present invention, the efficiency of an internal combustion engine can be improved.

[Brief explanation of drawings]

Figure 1 is a configuration diagram, Figure 2 is a specific configuration of the input/output interface, Figure 3 is a timing chart, Figure 4 is the configuration of the knocking detection device, Figure 5 is a waveform diagram, and Figure 6 is a cylinder internal pressure waveform. 7 and 8 show the specific configuration of the internal pressure sensor amplifier circuit and mixer, FIG. 9 shows the general flow, FIG. 10 shows the angle interrupt processing routine, and FIG. 11 shows the rotation synchronization processing routine. 12...CPU, 14...ROM, 16...R,
AM, 30th 2nd/2J Is 4 y C (C) '#8th 549th F! vt Kayao figure ApJerL6

Claims (1)

[Claims] 1. An internal combustion engine having an internal cylinder pressure sensor that detects the internal cylinder pressure of the internal combustion engine, a peak value detection circuit that detects the peak value of the output value of the sensor, and a knock detection circuit that detects knocking when knocking occurs. In the ignition timing control device, the pressure inside the cylinder is detected at a specific timing, and the ignition timing is advanced from the ignition timing at that timing until just before a knock occurs, and the crank angle is determined at which the peak of the pressure inside the cylinder immediately before the knock occurs is maximized. An ignition timing control device for an internal combustion engine, comprising means for correcting ignition timing.