JPS6270663A - Ignition timing control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent an engine operating condition from being seriously affected because of lack of an optimum ignition timing by allowing an ignition to be effected based on an approximate engine speed corresponding to a space between indicator signal maximum peaks or based on a specified ignition angle when a reference position generating circuit is judged to be abnormal. CONSTITUTION:An abnormal condition detection signal is generated unless the following signal is not outputted beyond a specified period of time since one reference position signal has been outputted. And a reference position generating circuit 3 is determined to be abnormal by detecting a space from the maximum peak position to the next maximum peak position by means of a counting means when the abnormal condition signal is presented. Then an ignition angle corresponding to an approximate engine speed is detected by the counting means, or a specified ignition angle is retrieved from a data map, which stores the information for the angle in advance in its ROM and the like contained, so as to be set in an ignition angle setting circuit 8 for commanding an ignition. Accordingly, this configuration is capable of preventing an engine operating condition from being seriously affected, because the reference position signal is not generated, besides an indicator peak position data is not provided when the reference position generating circuit 3 is out of order.

Description

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

Five holes communicating with the combustion chamber are bored in the cylinder head and other components of the combustion chamber of the back JJL internal combustion engine, and an acupressure sensor using a piezoelectric element is inserted into these holes to detect changes in the cylinder internal pressure as a so-called acupressure signal. can be obtained as It is also conceivable that a pressure gauge is interposed in the joint between the cylinder head and the cylinder block to provide acupressure signals.

Inside the engine cylinder during internal combustion engine operating conditions.
It can be seen that the pressure change is as shown by curve A in FIG. When the ignition system is triggered at the ignition angle e■a, the ignition delay θ
The air-fuel mixture is ignited at d, and the cylinder internal pressure then rises rapidly to the maximum pressure peak P (hereinafter referred to as shiatsu peak).
The process of descent is followed.

It is known that the crank angle position of this 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 provide this maximum output is at top dead center as shown in the figure. 1!2 (hereinafter referred to as ATDC
It was experimentally confirmed that the angle is between 12° and 13°. Therefore, assuming this ATDC'12° to 13° as the ideal crank angle position, the acupressure peak is set at ATDC12°.
An ignition timing control device using a finger pressure detection method has been proposed, which controls the ignition timing θIG to an ideal crank angle position of ~13 degrees.

Such an ignition timing control device directly detects the cylinder internal pressure using a finger pressure sensor or the like, generates a finger pressure signal representing the cylinder internal pressure, obtains finger peak position data for each engine cycle from the finger pressure signal, and compares it with crank reference position data. The ignition timing is advanced or retarded for each engine cycle. Incidentally, in such a finger pressure detection type ignition timing control device, a reference position generation circuit is provided which generates a reference position signal every time the crank rotation angle reaches a predetermined reference position. If an abnormality occurs in the position generation circuit and the reference position signal is no longer generated, accurate shiatsu peak position gutter will not be obtained, and proper ignition timing will not be achieved, which will adversely affect the engine operating condition. Therefore, it is desirable to take measures in case of emergency.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an ignition timing control device using a finger pressure detection method that can prevent deterioration of the engine operating condition when the reference position generation circuit is abnormal.

The ignition timing control device according to the first invention of the present application has the following j! Generates an abnormality detection signal that does not generate a quasi-level double signal, detects the interval from one maximum peak position of the acupressure signal to the next maximum peak position by a counting means, and when an abnormality detection signal exists, a reference position generation circuit is activated. It is characterized by determining that there is an abnormality and instructing engine ignition at an ignition angle according to the output signal of the counting means. Further, the ignition timing control device according to the second invention of the present application generates an abnormality detection signal when the next reference position signal is not generated for a predetermined period or more after the generation of the first reference position signal, and when the abnormality detection signal exists, the reference position generation circuit is activated. It is characterized by determining that there is an abnormality and commanding engine ignition at a predetermined ignition angle.

Example E Fig. 2 shows an ignition timing control device according to the present invention, in which a through hole is bored in a member such as a cylinder head that forms a combustion chamber of an internal combustion engine (not shown). An acupressure sensor 1 made of a piezoelectric element is closely inserted into the
The tip of the finger pressure sensor 1 is exposed inside the combustion chamber. Clock generation circuit 2 generates clock pulses synchronized with engine rotation. As a means for obtaining clock pulses synchronized with engine rotation, a photocoupler is combined with a slit disk that rotates in response to the rotation of the crankshaft and has many slits at equal intervals, and the output signal of the photocoupler is used to obtain clock pulses synchronized with engine rotation. Means for reducing the number of black pulses by 1q are known. The reference position generation circuit 3 generates a reference position signal, such as TDC (Top
DeadCenter) pulse is generated. This TDC
The pulse is passed through the slit disk used for clock generation circuit 2.
This can be obtained by providing a slit for DC pulses and a photocoupler for generating TI)C pulses. The peak hold circuit 4 holds the maximum value of the acupressure signal after being cleared by the reference position signal, and the comparator circuit 5 generates a peak detection signal when the acupressure signal itself falls below the maximum value.

The counter 6 for measuring the crank angle position counts clock pulses and is cleared by the reference position signal supplied to the C[, RDa. It shows the value. Further, when the count value of clock pulses reaches an upper limit value that is larger than the number of clock pulses generated by the clock generation circuit 2 during one engine cycle, the counter 6 enters an overflow state.
Raise the level of FQ child to high level. OVF of counter 6
The terminal is connected to the S (set) terminal of the RS flip-flop 15, and the R (reset 1~) terminal of the Noritsubu flop 15 is connected to the output end of the reference position generation circuit 3. The latch circuit 1o is configured to latch the count value of the counter 6 every time the peak detection signal from the comparison circuit 5 is supplied to its gate terminal 9. On the other hand, the decoder 11 supplies a read command signal to the ignition angle setting circuit 8 when the count value of the counter 6 reaches, for example, 64. count 1
The a64 corresponds to a crank angle that is larger than the crank angle at which the acupressure peak value is predicted to occur, and has obtained a reading timing that is not affected even if the valve seating noise of the exhaust valve mixes into the acupressure signal. There is. In response, the ignition angle setting circuit 8 reads the contents of the latch circuit 10 and determines the latch contents as peak position data θpx on the crank angle. It is also possible to consider a configuration in which the latched contents are supplied to the ignition angle setting circuit 8 via a gate circuit that listens to the gate in response to a read command signal from the decoder 11.

The ignition angle setting circuit 8 is constituted by a microprocessor or the like, and supplies desired ignition angle θ[G data to the ignition command circuit 9 based on the supplied peak position data θp× according to a program described later. The ignition command circuit 9 knows the current crank angle value θ19 by counting clock pulses using the reference position signal as a reference, and when this current value θig and the input θIG match, opens the ignition switch SW, thereby opening the ignition transformer T. Ignition current flows through the primary coil of the spark plug (not shown) to ignite the spark plug. Note that the ignition angle setting circuit 8 and the ignition command circuit 9 form an ignition command means.

Further, a differentiation circuit 13 is connected to the output end of the acupressure sensor 1 via a low-pass filter 12.

A reset signal is generated from the differentiating circuit 13, and the reset signal is sent to the CLR of the counter 6 via the gate circuit 14.
Supplied to the terminal. The gate circuit 14 is the OV of the counter 6.
When a high level signal is supplied from the F terminal, it turns on. A clock generation circuit 16 generates clock pulses at a predetermined period. This clock pulse is supplied to a counter 17 and counted. The output signal of the differentiating circuit 13 is supplied to the CL F< terminal of the counter 17, and when the output signal of the differentiating circuit 13 is at a high level, the count value OC of the counter 17 is reset to the initial value, that is, O, and counting starts again. do. The count value θC of the counter 17 immediately before resetting is the latch circuit 1
8 and is supplied to the ignition angle setting circuit 8.

FIGS. 3A to 3F are signal waveform diagrams illustrating the operation of the circuit of the above embodiment. That's right! The three quasi-position signals and clock pulses are as shown in FIGS. 3A and 3B, 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. 3(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 3 (G) shows the decoder 11
In this case, the high level is the read command signal.

On the other hand, when an acupressure signal as shown in FIG. 4(a) is supplied to the low-pass filter 12, the high-frequency component of the acupressure signal is removed by the low-pass filter 12, and the acupressure signal as shown in FIG. 4(b) is supplied from the low-pass filter 12. An output signal as shown is supplied to the differentiating circuit 13.

The differentiating circuit 13 differentiates the output signal of the low-pass filter 12 to obtain a pulse signal representing the maximum peak position of the acupressure signal as shown in FIG. 4(C). Since this pulse signal contains a high level, when it is supplied to the CLRCa terminal of the counter 17, the count value θC of the counter 17 is reset to O, and the clock pulse output from the clock generation circuit 16 is again processed by the counter 17. It begins to be counted. The count value θC of the counter 17 immediately before resetting represents the period from the maximum peak position of the shiatsu signal in one engine cycle to the maximum peak position of the shiatsu signal in the next engine cycle, and the count value θC is held by the latch circuit 18. Ru.

Now, if an abnormality occurs in the reference position generation circuit 3 and the generation of the reference position signal stops, the count value of the counter 6 will reach the upper limit value, and the counter 6 will be in an overflow state, so ○V
The level of the F terminal becomes high level. This high level is supplied as an abnormality detection signal to the S Pa terminal of the flip 70 knob 15 and held until a reference position signal is generated, and is also supplied to the gate circuit 14 to make the gate circuit 14 conductive. Differentiating circuit 1 depending on the conduction state of gate circuit 14
The pulse signal outputted from the counter 3 is supplied to the CLR terminal of the counter 6 via the gate circuit 14, and the count value of the counter 6 is reset to O. Therefore, the counter 6 starts counting, but repeats this operation until the reference position signal is generated. Further, when the reference position generating circuit 3 is abnormal, the value held in the latch circuit 10 does not change.

FIG. 5 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 an initial value (71G0) and determines whether or not a read command signal is generated from the decoder 11 (step S+).

Upon receiving the reading command signal, it is determined whether or not an abnormality detection signal is supplied from the flip-flop 15 (step S2). If it is determined that the abnormality detection signal is not supplied, the contents held in the latch circuit 10 are taken in as peak position data θpx (step S3). This peak position data θpx is the top dead center angle θTDC (here, θTD
C=O°. ) and, for example, an angle α of 12°, it is determined whether the sum is greater than or equal to (step S4), and if so, the ignition angle θIC is advanced by Δθ (step S4).
s) If it is smaller, the ignition angle θIG is retarded by Δθ (step Ss). On the other hand, if it is determined in step S2 that the abnormality detection signal is held and output by the flip-flop 15, the contents held in the latch circuit 18 are taken in (step S). The content held by the latch circuit 18, ie, the period from the maximum peak position of the finger pressure signal in one engine cycle to the maximum peak position of the finger pressure signal in the next engine cycle, approximately corresponds to the reciprocal of the engine speed at that time. The ignition angle θIG' corresponding to the captured contents held in the latch circuit 18 is retrieved from a data map stored in the internal ROM or the like and set (step Sa). Therefore, the ignition angle θI G ' is set according to the engine speed at that time. One cycle of operations from steps S1 to S8 from the above-mentioned start to enj: are sequentially executed in response to the zero clock pulse, and the cycle operations are repeated. The following programs are also similar in this regard.

In such an operation, the peak position data θpx is θTD
Feedback control is performed so that the peak position data θpx is equal to C+α, but the peak position data θpx is θT[)C+α±β(X
) may be controlled to be a value within the range.

Here, β(X) can be set by any one of engine speed Ne, throttle opening θth, engine suction negative pressure P, and by doing so, it is possible to improve the stability of the entire feedback system. can.

Note that when it is determined that the reference position generating circuit 3 is abnormal, the ignition angle θ1G- is not limited to being set approximately in accordance with the engine rotation speed, but may simply be fixed to a constant value.

FIG. 6 shows an example of an operating program when the ignition command circuit 9 is formed by a microprocessor. That is, the ignition command circuit 9 first determines whether or not an abnormality detection signal is generated (step 511). If the abnormality detection signal is not generated, it is determined whether the reference position signal is generated or not (step 812). When the reference position signal is detected, the current crank angle value θig in the built-in register is changed to θTDC.
(or a predetermined value) (step $13).

Next, the ignition angle data θIG from the ignition angle setting circuit 8 is taken in (step 814) and is compared with the current crank angle value θig, and when the condition θig=θ[G is satisfied, an ignition command is immediately issued (step 815). 816>, the ignition switch SW is opened. If 01g≠θIG, the unit crank angle δθ is added to Oig to prepare for the next program cycle (step 517). In step S+s, it is determined whether θ1g=θIG. No, 01
It is also possible to determine whether the difference between g and θIG is smaller than δO.

On the other hand, if the abnormality detection signal is generated, the reference position detection circuit 3 is abnormal, so it takes in the ignition angle data θIG' from the ignition angle setting circuit 8 (step 5ea), and also inputs the count value θC of the counter 17. Import (step 519
). Then, it is determined whether the ignition angle data θIG- and the count value θC match or not (step S20), 0+
When a-=DC, an ignition command is immediately issued to open the ignition switch SW. Incidentally, instead of reading the 31 value θC of the counter 17, the count value of the counter 6 may be read and it may be determined whether or not it matches the ignition angle data θ]G', and when they match, the ignition command may be generated. .

As is clear from the above, according to the ignition timing control device according to the present invention, when it is determined that the reference position generation circuit is abnormal, the engine rotation speed is approximately equal to that determined by the maximum peak interval of the finger pressure signal. The engine ignites at the appropriate ignition angle or at a predetermined ignition angle, so even if the ignition angle is not optimal depending on the cylinder internal pressure, the engine operating condition can be improved.
This can be prevented.

[Brief explanation of drawings]

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, Figs. 3 and 4 are signal waveform diagrams showing the operation of the device in Fig. 2, and Fig. 5 Flowchart 1 and FIG. 6 show the operation program of the part constituted by the microprocessor of the device shown in FIG.
It is. Explanation of symbols of main parts 8...Ignition angle setting circuit 9...Ignition command circuit 10...Wrap circuit 11...Decoder SW...・Ignition switch■・・・・・・Ignition transformer Figure 1 S “Submitted by the author of the series hE” December 24, 1985 II Licensed Office Aimiya OR Japanese Patent Application No. 211253 2, Invention Name of Internal Combustion Engine Ignition Timing Control Device 3, Relationship with each incident involving cuff S Patent Applicant Address: 2-1-1 Minami-Aoyama, Minato-ku, Tokyo Name:
(532) Honda Motor Co., Ltd. 4, Agent 104 Address Kyodo Building, 3-10-9 Ginza, Chuo-ku, Tokyo (Gengai 3-chome) Telephone: 543-7369 Name (79)
11) Patent attorney Motohiko Jutomura 5, date of amendment order Voluntary action

Claims (2)

[Claims] (1) A reference position signal generating means that generates a reference position signal every time the crank rotation angular position of the internal combustion engine reaches the reference angular position, a finger pressure sensor that generates a finger pressure signal representing the engine combustion chamber pressure, and a reference position of 1. peak position detection means for generating a shiatsu peak data signal representing the maximum peak position of the shiatsu signal from generation of the signal to generation of the next reference position signal; and ignition for commanding engine ignition at an ignition angle according to the shiatsu peak data signal. an ignition timing control device comprising a command means, an abnormality detection means for generating an abnormality detection signal when the next reference position signal is not generated for a predetermined period or more after generation of the first reference position signal; and one maximum of the acupressure signal. and counting means for detecting an interval from a peak position to the next maximum peak position, and the ignition command means commands engine ignition at an ignition angle according to an output signal of the counting means when the abnormality detection signal is present. An ignition timing control device for an internal combustion engine, characterized in that: (2) a reference position signal generating means that generates a reference position signal every time the crank rotation angular position of the internal combustion engine reaches the reference angular position; a finger pressure sensor that generates a finger pressure signal representing the engine combustion chamber pressure; and a reference position of 1. peak position detection means for generating a shiatsu peak data signal representing the maximum peak position of the shiatsu signal from generation of the signal to generation of the next reference position signal; and ignition for commanding engine ignition at an ignition angle according to the shiatsu peak data signal. an ignition timing control device comprising a command means, the ignition timing control device comprising an abnormality detection means for generating an abnormality detection signal when the next reference position signal is not generated for a predetermined period or more after generation of the first reference position signal; An ignition timing control device for an internal combustion engine, characterized in that it commands engine ignition at a predetermined ignition angle when an abnormality detection signal exists.