JPS61275582A - Internal combustion engine ignition timing control device - Google Patents

Abstract

PURPOSE:To perform ignition timing control suitable to engine characteristics by changing the increasing or decreasing ratio of an ignition angle depending on the feedback direction to the deviation between the measured manometric peak position of the cylinder inner pressure and its target position. CONSTITUTION:An ignition angle setting circuit 8 setting an ignition angle based on a manometric peak position data signal from a peak holding circuit 4 fed with output signals of a manometric signal generating circuit 1 generating a manometric signal indicating the cylinder inner pressure and a reference position signal generating circuit 3 is provided. An ignition switch SW is controlled to be closed by an ignition directing circuit 9 when the set ignition angle coincides with the present crank angle obtained by counting clock pulses from a clock generating circuit 2. The said ignition angle setting circuit 8 adjusts to advance or delay the set ignition angle in response to the deviation between the manometric peak position data value and its target data and changes the advance or dealy angle quantity against the same deviation quantity.

Description

[Detailed description of the invention] 15±1 The present invention relates to an ignition timing control device for an internal combustion engine.

115j A structure in which a through hole communicating with the combustion chamber is bored in a member constituting the combustion chamber such as the cylinder head of an internal combustion engine, and a pressure sensor using a piezoelectric element or the like is inserted into the hole to detect changes in cylinder internal pressure as a so-called finger pressure signal. You can get it. It is also conceivable to provide a pressure gauge in the joint between the cylinder head and the cylinder block to obtain a finger pressure signal.

It can be seen that the engine cylinder internal pressure changes during the operating state of the internal combustion engine as shown by the curve in FIG. When the ignition system is triggered at the ignition angle θI, the air-fuel mixture is ignited with an ignition delay θd, and the cylinder internal pressure then rapidly rises, reaches a maximum pressure peak P (hereinafter referred to as the shiatsu pressure peak), and then drops.

By the way, it is known that the crank angle position of the shiatsu peak is related to the state in which the engine exerts its maximum output, and the crank angular position of the shiatsu peak that can give this maximum output is the top dead center as shown in the figure. invasion (hereinafter referred to as ATDC)
) was experimentally confirmed to be between 12° and 13°. Therefore, this ATDol is set to an ideal crank angle position of 2° to 13°. Therefore, the acupressure peak is A
It is desirable to determine the ignition timing θIG so that the ideal crank angle position is between 12° and 13° TDC.

However, even if the ignition timing θIG is kept constant, the shiatsu peak changes from moment to moment depending on the engine operating condition.
Ignition timing & 1lIll that maintains the shiatsu peak at the optimum position
equipment is desired.

Therefore, an acupressure signal representing the cylinder internal pressure is obtained, the peak position of this acupressure signal on the crank angle is detected as the acupressure peak position, and this is used as an actual acupressure beep value to reduce the amount of deviation from the target acupressure peak value. A finger pressure signal response and ignition 118 period control device that adjusts the point-large angle as shown in FIG.

In such a finger pressure signal response type ignition timing control device, when the ignition angle is adjusted by the absolute value of the deviation of the actual measured finger pressure peak value from the target finger pressure peak value, that is, the angle corresponding to the amount of deviation, depending on the engine, the ignition angle changes, The peak value fluctuation may differ depending on the positive and negative directions. In such a case, if advance or retard control is performed at a constant angle regardless of the direction of fluctuation of the peak pressure value, ignition timing control that is suitable for the engine characteristics cannot be achieved.

Therefore, an object of the present invention is to provide good ignition timing control for an engine in which the amount of variation in the shiatsu peak position differs depending on the direction of the engine's ignition timing variation even if the amount of variation in the ignition timing is the same. An object of the present invention is to provide an ignition timing control device responsive to a finger pressure signal.

In the ignition timing control device according to the present invention, the amount of rIJ for controlling the ignition timing is made different depending on the direction of fluctuation of the acupressure peak value.

Support-1-1 FIG. 2 shows an ignition timing control system according to the present invention. In this system, an internal combustion engine (not shown)
Acupressure signal generating circuit 1 is obtained by drilling a through hole in a member such as a cylinder head forming a combustion chamber, and inserting a pressure sensor such as a piezoelectric element tightly into the through hole so that its detection head is exposed inside the combustion chamber. include. The clock generation circuit 2 generates clock pulses having a predetermined period or synchronized with engine rotation. The means for obtaining clock pulses synchronized with engine rotation is a disk that rotates in response to the rotation of the crankshaft, and a photocoupler is combined with a slit disk that has many slits at equal intervals, and the output signal of the photocoupler is used. Means for obtaining clock pulses are known.

The reference position generation circuit 3 generates a reference position signal, such as TDC (Top Dead Center
) generates a pulse. This TOC pulse can be obtained by providing a TDC pulse slit in the slit disk used in the clock generation circuit 2 and a photocoupler for TDC pulse generation. Peak hold circuit 4
is cleared by the reference position signal and then holds the maximum value in the acupressure signal, and the comparator circuit 5 issues an acupressure signal when the acupressure signal itself falls below the maximum value. A counter 6 for measuring the crank angle position counts clock pulses and is cleared by a reference position signal, and the count value of the counter 6 is, for example, 8-bit data and indicates the current value of the crank angle. The latch circuit 10 starts the counter 6 every time the peak detection signal from the comparator circuit 5 is supplied to its gate terminal 9.
On the other hand, the decoder 11 supplies the ignition angle setting circuit 8 with a read command signal when the count value of the counter 6 becomes, for example, 63.

The count value 63 corresponds to a crank angle that is larger than the crank angle at which the acupressure peak value is predicted to occur, and the reading timing is such that it will not be affected even if the valve seating noise of the exhaust valve mixes into the acupressure signal. It has gained.

In response, the ignition angle setting circuit 8 reads the contents of the latch circuit 10 and determines the latch contents as peak position information θpx on the crank angle. Note that a configuration is also conceivable in which the read command signal from the decoder 11 is used to input the latch contents to the ignition angle setting circuit 8 via the gate circuit. peak position information (data) θ
Based on px, desired ignition angle θIG data is supplied to the ignition command circuit 9 according to a program to be described later. The ignition command circuit 9 counts clock pulses using the reference position signal as a reference to know the current crank angle value θt9, and when the current value θi9 and the input θIG match, the ignition switch SW is turned on, thereby starting the ignition. The ignition current 'IIi flows through the primary coil of the transformer T, and ignition is performed by a spark plug (not shown). Note that the ignition angle setting circuit 8 and the ignition command circuit 9 form an ignition command means. Further, the ignition angle setting circuit 8 receives various engine parameters from the engine parameter sensor 12, that is, the engine rotation speed Ne.
There is also a mode that operates based on 1 suction negative pressure Pa, throttle bias θth, etc.

FIGS. 3A to 3F are signal waveform diagrams illustrating the operation of the circuit of the above embodiment. That is, the reference position signal and clock pulse are as shown in FIGS. 3(A) and 3(B), respectively. The acupressure signal changes as shown by the solid line in FIG. 3(C), and therefore the output of the peak hold circuit 4 changes as shown by the dotted line in FIG. 4(C). The comparison circuit 5 generates a peak detection pulse signal as shown in FIG. 3(D) at each maximum point of the acupressure signal. FIG. 3(E) shows numerically how the count value of the counter changes.

FIG. 3(F) shows numerically how the latched contents of the latch circuit 10 change. Figure 4 (G) shows the decoder 11
In this case, the level is the read command signal.

4th vJ shows an example of a program related to ignition control of the ignition angle setting circuit 8 of the device shown in FIG.

That is, in performing the ignition control operation, the ignition angle setting circuit 8 first sets the ignition angle θIG to the initial mmθ summer Go, waits for a read command signal from the decoder 11, and receives the read command signal. The contents latched by the latch circuit 10 are taken in as peak position information θP× (steps S1., S2).

Next, this peak position information θpx is the top dead center angle θTDC
For example, the ignition angle θ! G as Δθ
If the ignition angle is smaller, the ignition angle θtC is retarded by Δθ (step Ss). Steps S+ or Ss from the above start to end
One cycle of operation is sequentially executed in response to a clock pulse, and the cycle operation is repeated. The following programs are also similar in this regard.

FIG. 5 shows an example of an operating program when the ignition command circuit 9 is formed by a microprocessor. That is, when the ignition command circuit 9 detects the reference device signal, in step Sue, it sets the current crank angle value θ in the built-in register to θtoe (or a predetermined value) (step 5I2). Next, the ignition angle data θTG from the ignition angle setting circuit 8 is loaded (step +2) and used as the current crank angle value θi? Compare θ with r and set θ as −〇IG
Immediately when the condition is satisfied, an ignition command is issued (step SI4, 51s), and the ignition switch SW is turned on. On the other hand, when Ot')≠θIG, the unit crank angle δθ is added to θXt in preparation for the next program cycle (step S's), and in step S14, 01g=θ
The difference between 01g and θic is δ, not the judgment of IG or not.
It is also conceivable to make a determination as to whether or not it is smaller than θ.

In the above example, peak position data θP× is obtained for each engine cycle, and the ignition angle for the next cycle is determined by θP× in each cycle.

FIG. 6 shows an example of an operating program for the ignition angle setting circuit 8 in the ignition timing control device according to the present invention. In this program, acupressure peak data θP× is read when there is a reading command signal from the decoder 11 (step S+, 82 a), and θP× and (oTDC+α
) and advances or retards the angle (step S3a*S4a).

5sa) The basic flow is the same as the program shown in the flowchart of FIG.

However, in this example, θP× is understood as a data group that occurs in time series, and the acupressure peak position data obtained in the Nth engine cycle is defined as θpx (N).
(step 32a).

By the way, in the case of engine misfire, combustion within the cylinder does not occur and the acupressure peak position occurs near 0 TDC.

Further, since the acupressure peak position data in the cycle in which the engine misfire occurred is not based on normal combustion, it is not appropriate to use it as the basis for the acupressure peak position control in the next cycle. Therefore, first, θpx (N) is compared with 0TDC, and only when the difference exceeds Δθ, the process moves to the calculation of θpx (N) (step 320.21). This calculation step 8
In 21, the past engine cycle (N-1),
The stability of the feedback system is increased by correcting the current data value based on the acupressure peak position data value in the (N-2), . . . (N-n)th engine cycle.

As a specific example of ωn in the above formula, ω0=ω1=ω2fω
3iω4=115. It is also possible to set the average value of the past four data and the current data as the current data by setting ω5±ω6=...=ωlow0.

The averaging method is not limited to this, but the average of data an appropriate number of times is taken. Also, ωn-(1/L)n (L
>1, n>0).

θpx (N) obtained in this way and (θT D C+α
), advance angle and retard angle control is performed depending on the magnitude of the advance angle amount Δθ1 and retard angle amount Δ
θ2 is not necessarily set to the same value, but can be set to Δθ1>Δθ2 or Δθ1 minus Δ02 depending on the characteristics of the feedback system. Also, Δθ1. Δθ2 is θρ×(N
) and (OTDC+2).

On the other hand, when the difference between θpx (N> and θTDC is less than θ), as long as + <K+ 1, 1 is set to +1 (step S22.523) and the retard control is 0 (step 5s
a), and if misfires occur continuously and 1≧+tl, the ignition timing is initialized to be reset (step 52).
4). In addition, when 1θP×−θTDcl>Δθ, 1
is set to O and enters the next step (step 525). Incidentally, as shown in 1i1Q+, when the engine misfires, the retard control may not be performed and the next program cycle may be directly entered. This is due to the ignition timing 1. It is also possible to ignore the exhaust stroke data when using the II control device. This eliminates the need for an exhaust process discrimination sensor.

FIG. 7 shows yet another example of an operation program for the ignition angle setting circuit 8. In other words, in this program, the target value θP×i of θpx(N) is set to (OTDc
+α) is not set as a single angle, but the control target area is set as ΔθPxi±β(×) (step 530). By doing this, the stability of the entire feedback system is improved. Note that × in β(X) is the engine rotation speed Ne,
The throttle opening degree θTl-1 or the engine suction negative pressure Pa can be set to 1. It is also conceivable to change the value of β using a combination of these engine parameters as a variable. The other points are the same as the program shown in FIG. Note that β(X) can also be a constant β.

FIG. 8 shows another example of an operation program for the ignition angle setting circuit 8. That is, in this program, θp
x (N) without fixing the control target value θpxi
), the difference between the average value θpx (N) (-n+A 1/Δ・Σθpx(N)) and θpxi is added to the θpxi of the element N=n, and (2θpxi-θpx(N)) is set as the new θpxi. (Step 831).

The other parts are the same as the example program shown in the flowchart of FIG.

FIG. 9 shows another operating program of the ignition angle setting circuit 8. That is, in this program example, θp
Set the control target value θpxi of x (N) to 0 without making it a single angle.
The program is similar to the program shown in FIG. 7 in terms of feedback $ control so that θpx(N) falls within the target range of pxi±β(x). However, in this program, the correction amount of θIG is an odd-order function value F(θpx(N)−〇pxi) where the deviation amount of θpx(N) from θpxi (θpx(N)−〇pxi) is used as a variable. ). This odd-order l number F(Z) is, for example, Z.

It is an odd-order function having a single inflection point expressed by the general formula (Z-γ)0 such as Z* and ZS. In particular, when n≧3, the amount of feedback increases in accordance with the increase in the amount of deviation of θpx(N) from the target −〇pxi, and quick feedback control can be expected. On the other hand, if the amount of feedback becomes too large, there is a risk that the feedback system will go into a hunting state, so the maximum amount of feedback is limited. The above operations are performed by steps 832, 333, and 3γ in the flowchart of FIG.

Further, in this case, the broken line Q2 indicates that the step Ssa for retarding the engine by a predetermined angle of zero if a misfire occurs may be left in place, but may be omitted.

FIG. 10 shows yet another example of an operation program for the ignition angle setting circuit 8. That is, in this program, first, among various engine parameters, the engine speed Ne and the throttle opening θth are determined.

The suction negative pressure Ps is compared with predetermined reference values Nr, θr, and Pr, and the ignition angle θIG is fixed at the fixed ignition angle θrer within a range that does not exceed these reference values (step 84
0,841, Su, So), 14 quasi-ignition angle θIGr
It is also conceivable that the value may be varied depending on engine parameters such as engine speed, or may be selected from map values based on the engine parameters. Also, Ne, θth, Pa
When any one of them exceeds the reference value Nr, θr, pr, respectively, a feedback control operation is started. To explain the reason for switching between θIG determination by feedback control and fixed θIG according to engine parameters, firstly, when the engine speed is low, the pressure peak due to air compression due to explosion in the cylinder is This is because the acupressure peak near top dead center appears larger. The change in acupressure in this case is shown by the dashed line in FIG.

In addition, a small throttle opening or a low suction negative pressure indicates a low load or extremely low throttle opening, and the change in finger pressure in such a case is shown by the solid line curve in Figure 11. Shown in In this case as well, the maximum acupressure peak position is near TDC, which is not suitable for feedback control of the ignition angle. Note that the dotted line curve in FIG. 11 shows how the finger pressure changes under normal operation. Note that either steps 841 or 342 can be omitted.

The engine operating state is either low engine speed, extremely low throttle opening, or light load (if it is determined that the engine is in normal operating state, the shiatsu peak position θpx (N)
You can also start reading.

However, in this program, the difference 〇 + c (N-1) between the set ignition angle θ■c (N-1) in the previous cycle and the set ignition angle θTG (N-2) in the cycle before the previous cycle is calculated. (step 544).

Next, when the presence of the reading command signal is detected, the acupressure peak data θpx (N) is taken in (step S+, 5
za). After this, the contents of step 344 may be executed.

Next, in step S6) to calculate the difference Δθpx (N) between the current θpx (N) and the previous θpx (N-1), t
Δθpx (N) for Δθ+c(N-1)
Obtain the ratio K(N) (step Ss) o Then, step 820.321.822.323°824,82
5.83 a) Tweet Execute in the same manner as in Figure 6.

Then, when advancing or retarding the previous θIG (N-1) according to the comparison result with the target value of θpx (N), only K(H)・Δθ1 or K(N)・Δθ2 is required. The previous time θIe(N-1) is decreased or increased (step Sa, S hammer).

This is because the current peak position θpx(N) is due to the previous set ignition angle θ+c(N-1), and the previous peak position θpx(N-1) is due to the previous set ignition angle θ+c(N-2).
Therefore, from θ-1c(N-2) to θIG(
θpx( by the change Δθrc(N-1) to N-1>
Change amount Δθpx (N) from N-1) to θpx (N)
The degree of influence on the current setting ignition angle θIc for the next engine cycle is expressed by K(N).
This is reflected in the advance angle or retard angle control of (N).

FIG. 12 shows a useful subroutine for the ignition angle setting circuit 8 (used in the ignition angle setting circuit 8) when an oscillator such as a crystal oscillator is used as the clock generation circuit 2 to generate a clock pulse signal of a constant frequency independent of the engine speed. It is a program.

The ignition angle setting circuit 8 including this subroutine program determines whether a reference position signal such as a TDC pulse exists or not (step Sso), and if it does not exist, the period of absence of the reference position signal is determined (K2 period)
It is determined whether the value exceeds the value (step 551), and if it does not, 1 is added to the constant 2 and the process ends (step S5□). Reference signal absent I]ll5I is (K2 lx
When the set ignition angle θ [G is returned to the initial value θIGO, K2 is set to zero, and a cancel flag that ignores the θP × data at this time is added to this θP × data (step 553). Note that when the presence of the reference position signal is detected, 2 is set to zero (step 554).
.

This is because if the reference position signal is not obtained for a predetermined period of time or longer, it is determined that the engine has stopped and preparations are made for the next engine start.

1 and 11 As is clear from the above, according to the ignition timing control device responsive to the finger pressure signal according to the present invention, the rate of increase/decrease in the ignition angle is made different depending on the direction of feedback with respect to the deviation of the finger pressure peak position, which improves the engine characteristics. This is preferable because it is possible to achieve an ignition timing υIm that matches the ignition timing υIm.

[Brief explanation of the drawing]

Fig. 1 is a graph illustrating internal pressure changes in the engine cylinder, Fig. 2 is a circuit diagram showing an embodiment of the present invention, Fig. 3 is a signal waveform diagram showing the operation of the device shown in Fig. 2, and Figs. FIG. 5 is a flowchart showing the operation program of the portion constituted by the microprocessor of the device shown in FIG. 2.FIGS. 6 to 10 and 12 are flowcharts showing the operation mode program of the ignition angle setting circuit of FIG. Char 1-1 No. 11
The figure is a graph showing that the acupressure change curve depends on driving conditions. Explanation of symbols of main parts 8...Ignition angle setting circuit 9...Ignition command circuit 10...Latch circuit 11...Decoder SW...・Ignition switch T...Ignition transformer Applicant: Honda Motor Co., Ltd. Agent Patent attorney: Motohiko Fujimura Figure 4 Figure 5 End Figure 11 Figure 12 Entrance procedure...Original document (spontaneous) 1985 October 29th

Claims (1)

[Claims] a reference position signal generating means for generating a reference position signal each time the engine rotational angular position of the internal combustion engine reaches a reference angular position; a finger pressure signal generating means for generating a finger pressure signal representing the engine cylinder internal pressure; peak position detection means for sequentially generating acupressure peak position data signals representing the maximum peak position of the acupressure signal up to the next reference position pulse; and ignition angle setting means for sequentially setting an ignition angle based on the acupressure peak position data signals. An ignition timing control device for an internal combustion engine, comprising ignition command means for commanding engine ignition at an ignition angle set by the ignition angle setting means, wherein the ignition angle setting means is configured to control the target data value of the shiatsu peak position data signal. An internal combustion engine characterized in that when advancing or retarding a set ignition angle in accordance with the amount of deviation with respect to shiatsu peak position data, the amount of advance and the amount of retardation are made different for the same amount of deviation. Ignition timing control device.