JPS63280856A - Ignition timing controller - Google Patents

Abstract

PURPOSE:To correctly control the ignition timing of an engine even in the transient state of the engine by correcting the output of a means for detecting the intake quantity per intake cycle (A/N) of the engine, after smoothing, in the transient state of the engine. CONSTITUTION:A Karman's vortex type air flow sensor 13 outputs pulse signals according to the air quantity inhaled into an engine 1, and a crank angle sensor 17 outputs pulse signals according to the revolution of the engine 1. An A/N detecting means 20 counts the output pulse quantity of the air flow sensor which is inputted at each prescribed crank angle of the engine 1. Further, an A/N calculating means 21 calculates the pulse quantity corresponding to the output of the air flow sensor 13 which corresponds to the air quantity inhaled by the engine 1, and AN is made smooth and correct. A control means 22 controls an injector 14 and an ignition coil 19 according to the output of the AN calculating means 21 and each output of the crank angle sensor 17 and a water temperature sensor 18.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an internal combustion engine that detects the intake air amount of the internal combustion engine using an intake air amount sensor, and controls the ignition timing of the internal combustion engine based on the detected output and the engine rotation speed. The present invention relates to an ignition timing control device.

[Conventional technology]

Tips when controlling the ignition timing of an internal combustion engine) - Place a Karman vortex type intake air sensor (hereinafter abbreviated as AFS) upstream of the valve, and calculate the amount of air per intake air of the engine calculated from the output of this AFS. Intake iA/N (also abbreviated as AN) and engine speed [based on this, m8! ! It has been established that the ignition timing of the engine can be controlled.

[Problem that the invention seeks to solve]

However, with the above-mentioned conventional device, during transient special acceleration of the engine, there is a delay in processing the A/N calculation, or the AFS detects the engine intake air amount to be lower than the actual amount, so the ignition timing is lower than the engine's request. There was a problem in that the angle shifted toward the advance side, causing knocking.

[Means for Resolving Problems] The ignition timing control device according to the present invention is provided with a correction means for correcting the output of the smoothing means for smoothing the A/N ratio during engine transients.

(Function) The correction means in this invention corrects the output of the smoothing means for smoothing the A/N output during engine transients, and the A/N output that causes an error during engine transients is corrected by the smoothing means. The error is corrected by the smoothing by the correction means and the correction by the correction means, and the optimum ignition timing is obtained.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

Fig. 3 shows a model of the intake system of an internal combustion engine, where 1 is the engine, which has a volume of VC per stroke, and is connected via an AFS 13, which is a Karman vortex flowmeter, a throttle valve 12, a surge tank 11, and an intake pipe 15. Air is sucked in by the injector 14, and fuel is supplied by the injector 14. Also, here, the volume from the throttle valve 12 to the engine 1 is assumed to be . 16 is an exhaust pipe.

FIG. 4 shows the relationship between the intake air amount and a predetermined crank angle in the engine 1, and (,) indicates the predetermined crank angle (hereinafter referred to as SGT) of the engine 1. (b) is the air amount Q1 passing through AFS13, (c) is the engine 1
The amount of air Q, , Td) taken in by the AFS 13 indicates the output pulse f of the AFS 13. Further, the period of the n-2 to n-1 rises of SGT is tn-1, the period of the n-1 to n-th rises is t, and the period is t. -, and t. to AFS1
The amount of intake air passing through 3 is Q, respectively. −〇 and Q,
,. 2. Let Qll(I+-11 and Qe(n
Let it be l. Furthermore, the average pressure in the surge tank 11 and the average intake air temperature during periods tn-1 and t, respectively are P
and Pa(nl and T, i-0, and mushi1n-11 bi'r, , , where, for example, Q, , .-1,
corresponds to the number of output pulses of the AFS 13 during trl-1. Also, since the rate of change in intake air temperature is small, Ta (1,1
-11" Ta lnl and the charging efficiency of engine 1 is constant, P a (n-11"Vc""Qa(n-11'R")
r,,,,...-[11P,,,,,Ve=
Qa lnl・R-T...
...(2) becomes. However, R is a constant. and,
If the amount of air accumulated in the surge tank 11 and intake pipe 15 during period t is ΔQa+n+, then x(p −p) ...(3)
s (nl Hatake (n-11), and equations (1) to (3) are obtained. Therefore, the air iQ that the engine 1 takes in during period 1 is converted to the air amount m (n
It can be calculated using equation (4) based on lQ.

Kokote, V = 0.54', V, = 2.51, and Qml. ,=0.83XQ,,. −,,+0.1
7XQ, ......(5).

Figure 1 shows the configuration of an engine ignition timing control device, 1
0 is an air cleaner disposed upstream of the AFS 13, and the AFS 13 outputs a pulse as shown in FIG. 4(d) according to the amount of air taken into the engine 1. 4 (al) (for example, the crank angle is 180'' from the rising edge of the pulse to the next rising edge).

20 is an AN detection means, which calculates the number of output pulses of the AFS 13 that fall between a predetermined crank angle of the engine 1 based on the output of the AFS 13 and the output of the crank angle sensor 17, and calculates the intake air amount A/N per predetermined crank angle. calculate.

Reference numeral 21 denotes an AN calculation means including a smoothing means and a correction means, which performs calculations similar to equation (5) from the output of the AN detection means 20, and calculates the AFS corresponding to the amount of air considered to be taken in by the engine 1. Calculate the number of pulses equivalent to the output of 13. That is, A/N smoothing is performed. Further, after smoothing, further correction is performed. The control means 22 also controls the engine 1 based on the output of the AN calculation means 21, the output of the water temperature sensor 18 (for example, a thermistor) that detects the cooling water temperature of the engine 1, and the output of the crank angle sensor 17 that detects the rotation speed of the engine 1. Injector 14 corresponds to the amount of air taken in by
The drive time and energization of the ignition coil 19 are controlled, thereby controlling the amount of fuel supplied to the engine 1. or,
The ignition coil 19 supplies its output voltage to the ignition plug 24 via the power distributor 23 for ignition.

FIG. 2 shows a more specific configuration of this embodiment, and 30 is A.
FS 13, water temperature sensor 18 and crank angle sensor 1
7 is a control device that receives an output signal from A in FIG.
It corresponds to the N detection means 20 to the control means 22, and the ROM 41.
A microcomputer with RAM42 (hereinafter referred to as C
Abbreviated as PU. ) 40. Also, 31 is A
The 2 frequency divider 32 connected to the output of the FS13 uses the output of the 2 frequency divider 31 as one input, and the other input terminal is connected to the CPU 4.
It is an exclusive OR gate connected to input P1 of 0, and its output terminal is connected to counter 33 and input P3 of CPU 40. 34 is the water temperature sensor 18 and the A/D converter 3
A waveform shaping circuit 36 is connected to the interface 36 and receives the output of the crank angle sensor 17, and the output is input to the interrupt input P4 of the CPtJ40, the timer 47, and the counter 37. Further, 38 is a timer connected to the interrupt input P5, and 39 is a timer connected to the interrupt input P5.
An A/D converter that performs /D conversion and outputs it to the CPU 40,
43 is a timer provided between the CPU 40 and the driver 44, and the output of the driver 44 is connected to each injector 14. Reference numeral 45 denotes an interface to which the output of the crank angle sensor 17 is input, and inputs a 1 degree signal of the crank angle to timers 46 and 47. The output of timer 47 is output from timer 46
and input to the reset terminal of DF/F48. or,
The output of the timer 46 is input to the set terminal of the DF/F 48, and the output of the DF/F 48 is input to the ignition coil 19 via the driver 49. Furthermore, timers 46 and 47
is inputted with the output of the CPU 40.

Next, the operation of the above configuration will be explained. The output of the AFS 13 is divided by a frequency divider 31 and input to a counter 33 via an exclusive OR gate 32 controlled by the CPU 40. Counter 33 measures the period between falling edges of gate 32's output. The CPU 40 inputs the falling edge of the gate 32 to the interrupt input P3 fi, performs an interrupt process every time the output pulse period of the AFS 13 or this frequency is divided by two, and measures the period of the counter 33. The output of the water temperature sensor 18 is converted to voltage by the interface 34, and the output is converted to voltage by the A/D
It is converted into a digital value by the converter 35 at predetermined time intervals and is taken into the CPU 40. Crank angle sensor 17
The output is inputted to the interrupt input P4 of the CPU 40, the timer 47, and the counter 37 via the waveform shaping circuit 36.

The CPU 40 performs an interrupt process every time the crank angle sensor 17 rises, and detects the period between the rises of the crank angle sensor 17 from the output of the counter 37. The timer 38 generates an interrupt signal to the interrupt input P5 of the CPU 40 at predetermined intervals.

The A/D converter 39 converts the battery voltage (not shown) into an A/D converter.
D conversion is performed, and the CPU 40 takes in data of this battery voltage at predetermined time intervals. The timer 43 is preset in the CPU 40 and is triggered by the output capo-1-P2 of the CPU 40 to output a predetermined pulse width, and this output drives the injector 14 via the driver 44. Also, CPU40L
The energizing angle T is applied to the t timer 46. , and also sets the ignition timing in the timer 47. Timers 46 and 47 are the 10th
As shown in the figure, 1 is output from the crank angle sensor 17.
° Counts the signal and outputs the signal to DF/F 48 when it reaches 0. The timer 47 starts counting at the rise of the crank angle, and when it reaches 0, resets the DF/F 48 and cuts off the current of the ignition coil 19. The timer 46 starts counting down when the timer 47 reaches 0, and when it reaches 0, sets the D-F/F 48 and turns on the ignition coil 1.
9 is energized.

Next, the operation of the CPU 40 will be explained using flowcharts shown in FIG. 5 and FIGS. 7-8. First, Figure 5 shows the CPU 40
When a reset signal is input to the CPU 40, the RAM 42, input/output ports, etc. are initialized in step 100, and the output of the water temperature sensor 18 is A/D converted in step 101, and is stored in the RAM 42 as WT. . In step 102, the battery voltage is A/D converted and stored in the RAM 42 as VB. Step 10
3, then 30/T from the period TFl of the crank angle sensor 17
Calculate Fl and calculate the rotation speed N. Step 1
From load data AN and rotation speed N, which will be described later in 04, AN・
N/30 is calculated to calculate the output frequency F of AFSI3. In step 105, the output frequency F.

As shown in FIG. 6, the dynamic basic drive time conversion coefficient K is calculated based on fL set for F. Step 106
Then, the conversion coefficient K is corrected using the water temperature data WT, and the drive time conversion coefficient is set to 1 and stored in the RAM 42. In step 107, the data is stored in the ROM 41 in advance from the battery voltage data VB.
Map the data table /L, f, stored in , and waste time T. is calculated and stored in the RAM 42. In step 108, the energization angle T of the ignition coil 19 is determined at the rotational speed N.

,,l, and in step 109 T'=180-T
is calculated, and T'o1. is sent to the timer 46 in step 110. l
Set. After processing step 110, step 1 is performed again.
Repeat the process of 01.

FIG. 7 shows the interrupt processing for the interrupt input P3, that is, the output signal of AFSI3. In step 201, the output T of the counter 33 is detected and the counter 33 is cleared. This T
F is the period between the rises of gate 32; Step 20
In step 203, the period) is stored in the RAM 42 as the output pulse period 1 of the AFS 13, and in step 203, the remaining pulse data P is added to the integrated pulse data P8. , and make the new integrated pulse data 8. This integrated pulse data PR is obtained by integrating the number of pulses of the AFSI 3 output during the rise of the crank angle sensor 17, and is treated as one pulse of the AFSI 3 multiplied by 156 for convenience of processing.

In step 204, the remaining pulse data P is set to 156, and in step 205, Pl is inverted, and the interrupt processing is completed.

FIG. 8 shows the CPU 40 using the output of the crank angle sensor 17.
The interrupt processing when an interrupt signal is generated at the interrupt input P4 is shown. In step 301, the cycle between the rises of the crank angle sensor 17 is read from the counter 37, and the cycle is divided by R.
It is stored in AM42 and the counter 37 is cleared. If in step 302 there is an output pulse of AFSI 3 within the period -, then in step 303 the time difference Δt between the time tot of the immediately preceding output pulse of AFS 13 and the current interrupt time t02 of the crank angle sensor 17 is calculated as Δt=t02-tOf. Calculate this and set it as the period T8. If there is no output pulse of AFSI3 within the period TFl, set the period TR as the period - in step 304. In the subtub 305, 156XT, /'r
From the calculation of A, the time difference ΔtltAF813 is converted into output pulse data ΔP. That is, the pulse data ΔP is calculated assuming that the previous output pulse period of the AFSI 3 and the current output pulse period of the AFS 13 are the same.

In step 306, if the pulse data ΔP is smaller than 156, the process proceeds to step 308; if it is larger, ΔP is clipped to 156 in step 307. In step 308, the pulse data ΔP is subtracted from the remaining pulse data P to obtain new remaining pulse data ΔP. In step 309, if the remaining pulse data P0 is positive, the process goes to step 313; otherwise, since the calculated value of the pulse data ΔP is too larger than the output pulse of AFSI3, the process goes to step 310, where the pulse data Δpji! p, and the remaining pulse data is set to zero in step 312. In step 313, the pulse data ΔP is added to the integrated pulse data a to obtain new integrated pulse data P8. This data corresponds to the number of pulses that the AFSI 3 is thought to have output during the current rise of the crank angle sensor 17. In step 314 (
5) Perform the calculation corresponding to the formula. That is, from the load data AN calculated up to the previous rise of the crank angle sensor 17 and the integrated pulse data P7, K, AN+ (to 1-)
P, is calculated and the result is used as the new load data A.
Let it be N.

In step 315, if this load data AN is larger than a predetermined value a, it is clipped to a in step 316 to prevent the load data AN from becoming too large than the actual value even when the engine 1 is fully opened.

In step 317, the integrated pulse data PFl is cleared. In step 318, the load data AN and the drive time conversion coefficient are converted into □, and the wasted time is calculated as the drive time data T, =AN -
By calculating K1+-, setting drive time data T2 in the timer 43 in step 319, and triggering the timer 43 in step 320, the injector 14 is driven in accordance with the data T1 when the amount of ice reaches four. In step 321, the rotation speed N9 is calculated from the TPI described above. In step 322, the deviation (rate of change) ΔAN between the current value of AN and the previous value of AN is calculated, in step 323 ΔAN is added to the current AN to obtain AN, and in step 324, AN is calculated by β1 and β2. Clip between. Step 32
In step 5, the ignition timing A is determined from AN, N, and by mapping from the data table f5 shown in FIG.
7, and the interrupt processing is completed.

FIG. 9 shows the timing of clearing the flag in the processing of FIGS. 5, 7, and 8, in which (a) shows the output of the branching device 31, and (b) shows the output of the crank angle sensor 17.
shows the output of (C) is the remaining 9 pulse data P. shows,
Po, = Po-156
The calculation result is changed to T, /TA (this corresponds to the processing in steps 305 to 312). (dl indicates a change in the accumulated pulse data, and shows how the remaining pulse data P is accumulated each time the output of the branching unit 31 rises or falls.

In the above embodiment, the output pulses of the AFS 13 during the rise of the crank angle sensor 17 are counted, but this may also be during the fall of the crank angle sensor 17, or the number of output pulses of the AFS 13 during several cycles of the crank angle sensor 17 may be counted. Also good. Also, A
Although the output pulses of the FS 13 are counted, the number of output pulses multiplied by a constant corresponding to the output frequency of the AFS 13 may be counted.

〔Effect of the invention〕

As described above, according to the present invention, the intake air amount A/N per intake of the engine is detected by the AN detection means, and the A/N of the engine is detected.
After smoothing N using a smoothing means, correct A/
N is calculated and the ignition timing is controlled based on the A/N and engine speed, and the ignition timing is controlled accurately by correcting deviations of the A/N from the actual value during engine transients. Can be done.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an ignition timing control device according to the present invention, FIG. 2 is a block diagram showing a specific example of the ignition timing control device for the same internal combustion engine, and FIG. 3 is a block diagram of an ignition timing control device according to the present invention. FIG. 4 is a diagram showing the relationship between the intake air amount and the crank angle, and FIGS. 5, 7, and 8 are diagrams showing a model of an engine intake system. Flowchart showing the operation of the ignition timing control device, No. 6
The figure shows the relationship between the basic drive time conversion coefficient and the AFS output frequency. Figure 1 is a timing chart showing the timing of the flows in Figures 7 and 8. Figure 10 is a timing chart showing the on/off operation of the ignition coil. Figure 11 is an ignition timing map stored in the ROM. 1... Engine, 12... Throttle valve, ゛13
°°Air flow sensor (Karman i flow mg+), 15
...Intake pipe, 17...Crank angle sensor, 19...
Ignition coil, 20...AN detection means, 21...AN calculation means, 22...control means. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (2)

[Claims] (1) The intake air amount detection means, which is arranged upstream of the throttle valve, detects the intake air amount of the engine, the engine rotation speed detection means detects the engine rotation speed, and the output of the intake air amount detection means is detected between predetermined crank angles of the engine. AN detecting means for detecting, a smoothing means for smoothing the output of the AN detecting means, a correcting means for correcting the output of the smoothing means during engine transients, and an engine ignition based on the output of the engine rotation speed detecting means and the correcting means. An ignition timing control device comprising a control means for controlling timing. (2) The ignition timing control device according to claim 1, wherein the correction means performs the correction according to a change in the output of the AN detection means.