JPS6235073A - Ignition timing control device in internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent engine stalls and to aim at promoting engine warm-up with the use of an instruction pressure detection type ignition control device, by retarding the ignition angle during fast idle operation. CONSTITUTION:An ignition angle setting circuit 8 receives a read-out instruction signal from a decoder 11 and takes in the latch content of a latch circuit 10 as an instruction pressure peak position data. Then, it is determined whether the instruction pressure peak position data is greater than the sum of the top dead center angle and a predetermined angle, and if it is greater, a spark advance is made while if it is less, a spark retardation is made to set an ignition angle. At this time when it is determined that the rotational speed of the engine is lower than a predetermined fast idle rotational speed and the temperature of engine cooling water is lower than a predetermined value in accordance with a signal from an engine parameter sensor 12, the ignition angle is retarded by a predetermined angle.

Description

[Detailed description of the invention] Ryookatate 1 The present invention relates to an eight position ignition timing control for an internal combustion engine.

11. A through hole communicating with the combustion chamber is drilled 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 through hole to detect changes in the 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 curve A in FIG. When the ignition system is triggered at the ignition angle θIG, the ignition delay θd
The air-fuel mixture is then ignited, and the cylinder internal pressure then rises rapidly, reaches a maximum pressure peak P (hereinafter referred to as the shiatsu pressure peak), and then drops.

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. It was experimentally confirmed that the ATDC is between 12° and 13°. Therefore, assuming that this ATDCI 2° to 13° is the ideal crank angle position, the acupressure peak is set to ATDCI 2° to 1
Adjust the ignition timing θ to achieve the ideal crank angle position of 3°.
An ignition timing control device using a finger pressure detection method has been proposed.

Such an ignition timing control device directly detects the cylinder internal pressure, obtains shiatsu peak position data for each engine cycle using a shiatsu signal representing the cylinder internal pressure, and advances the ignition timing for each engine cycle by comparing it with crank reference position data. Or it is designed to be delayed.

By the way, during the first idle after the cold start of the engine, the engine oil is cold and has a high viscosity, and the engine wears a lot of horsepower, so a large starting horsepower is required.

Therefore, it is desirable to appropriately control the ignition angle in the above-mentioned finger pressure detection type ignition timing control device during the first idle to prevent engine stall and promote engine speed.

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 engine stalling during fast idling and promote warm-up.

The ignition timing control device according to the present invention is characterized by retarding the ignition angle when the engine is at first idle.

Figure 2 of the backyard diagram shows an ignition timing control 11 device according to the present invention. It includes an acupressure signal generating circuit 1 obtained by closely inserting a pressure sensor such as a piezoelectric element into the combustion chamber so that its detection head is exposed inside the combustion chamber. 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 a large number of slits at equal intervals to output the photocoupler. Means for obtaining clock pulses by signals are known.

The reference position generation circuit 3 generates a reference position signal such as TDC (Top Dead Center) indicating that the crank angular position, that is, the engine rotational angular position has reached the reference position.
r) Generate a pulse. This TDC 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. 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 issues a peak detection 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 is designed to latch the count of 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 latches the count of the counter 6
When the count value reaches 64, for example, a read command signal is supplied to the ignition angle setting circuit 8. The count value 64 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 the acupressure signal is not affected by valve seating noise of the exhaust valve. 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. 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 opens the gate in response to a reading command signal from the decoder 11.

The ignition angle setting circuit 8 is configured by a microprocessor or the like, and sets a desired ignition angle θ based on the supplied peak position information (data) θpx according to a program described later.
The IG data is supplied to the ignition command circuit 9.

The ignition command circuit 9 counts clock pulses based on the reference position signal to know the current crank angle value θig, and when this current value θig and the input θ[G match, the ignition/switch SW is opened. Ignition current flows through the primary coil of the ignition 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 is connected to an engine parameter sensor 12.
Various engine parameters, that is, engine speed N
A mode in which the engine operates based on the intake pressure P8, the throttle opening θth, the engine cooling water ffiTw, etc. may also be provided.

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 the clock pulse are as shown in FIGS. 3A and 3B, respectively. The acupressure signal changes as shown by the solid line in FIG. The output of the hold circuit 4 is as shown by the dotted line in FIG. 3(C).The comparator 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.

FIG. 4 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 carrying out the ignition control operation, the ignition angle setting circuit 8 first sets the ignition angle θIC to the initial value θl-C0 and waits for a reading command signal from the decoder 11.
When receiving the read command signal, the contents latched by the latch circuit 10 are taken in as peak position information θp× (step S+, 82). Next, this peak position information θp×
Determine whether the angle is greater than or less than the sum of the top dead center angle θTDC (here, θroc=0°) and the angle α of, for example, 12° (Step S3). If it is, advance the ignition angle θrc by Δθ. (Step Sa) Also, if the ignition angle θ is smaller, the ignition angle θ
The TG is retarded by 80 degrees (step Ss). After setting the ignition angle θIG, it is determined whether the engine speed Ne is smaller than a predetermined fast idle speed Ner (step Ss). Ne
In the case of <Ner, it is further determined whether or not the engine cooling water W T w is lower than a predetermined low temperature T Wr (step SA). If Tw<Twr, the ignition angle θIG is set to a predetermined angle Δ
The angle is retarded by θr (step Ss). On the other hand, Ne≧
If Ner or 7w≧7wr, no retardation is performed by the predetermined angle Δθr. The operations of one cycle of steps S1 to S8 from the start to the end described above are sequentially executed in response to clock pulses, and the cycle operations are 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 (step 511), the current crank angle value θig of the built-in register is
is set to θtoe (or a predetermined value) (step 512). Next, the ignition angle data θrG from the ignition angle setting circuit 8 is taken in (step SI4), and this is compared with the current crank angle value θig, and when the condition θig−0IG is satisfied, an ignition command is immediately issued (step SI4.
8I5), open the ignition switch SW. On the other hand, θ
ig≠θ! In the case of G, the unit crank angle δθ is added to θia in preparation for the next program cycle (step 816).
. In step S14, instead of determining whether θ1g=θrG, it may be possible to determine whether the difference between 61g and θIG is smaller than δθ.

In the above example, peak position data θp× is obtained for each engine cycle, θpx in each cycle determines the ignition angle θrG for the next cycle, and during fast idle, the ignition angle θIG is retarded by a predetermined angle Δθr. This is the reason.

FIG. 6 shows another example of an operation program for the ignition angle setting circuit 8. In this program, the ignition angle setting circuit 8 first starts at step S as in the above program.
+, 82 is executed, and then it is determined whether the engine speed Ne is smaller than the predetermined idle speed Net (
Step 521).

If Ne≧Ner, the read peak position information θp
It is determined whether x is larger or smaller than the sum of the top dead center angle θTDC and the angle α of, for example, 12° (step 522), and if it is, the ignition angle θIG is advanced by Δθ1 (step 523). If so, the ignition angle θIG is retarded by Δθ1 (step 524). On the other hand, if Ne<Ner, it is determined whether the engine cooling water temperature TW is smaller than the predetermined temperature Twr (step S25). TW≧TW
If r, execute step S22, and if TW<TWr, the read peak position information θpx is the top dead center angle θT.
Determine whether it is greater or less than the sum of DC and angle β (β>α) in step S2[i]. If it is, advance the ignition angle θIG by Δθ2 (step 527); if it is smaller, ignition The angle θIG is retarded by Δθ2 (step 5
28).

In the above example, during fast idle, the ignition angle is retarded by controlling the engine so that the start position is greater than the sum of the top dead center angle θTC)C and the angle α.

In each of the above-described embodiments of the present invention, the idle state of the engine is detected from the engine rotation speed and the cooling water temperature, but the present invention is not limited to this. For example, it may be detected from the throttle opening, the vehicle speed, and the cooling water temperature. It is clear that it is also good.

As is clear from the above, the ignition timing control device according to the present invention retards the ignition angle when the engine is at first idle, so that appropriate engine output can be obtained, engine stall can be prevented, and the engine can be warmed up. It is possible to promote the development of seashores.

[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, 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 an operating program of a portion constituted by the microprocessor of the device shown in FIG. 2, and FIG. 6 is a flowchart showing another operating mode program of the ignition angle setting circuit of FIG. 2. Explanation of symbols of main parts 8...Ignition angle setting circuit 9...Ignition command circuit 10...Latch circuit 11...Decoder SW...・Ignition switch■・・・・・・Ignition transformer Applicant: Honda Motor Co., Ltd. Agent Patent attorney: Motohiko Fujimura Proposed city official letter (voluntary) October 29, 1985

Claims (1)

[Claims] Reference position signal generating means for generating a reference position signal each time the crank rotation angular position of the internal combustion engine reaches the reference angular position; Shiatsu signal generating means for generating a finger pressure signal representing engine combustion chamber pressure; and 1. Reference position signal generating means. peak position detection means for generating an acupressure peak data signal representing the maximum peak position of the acupressure signal from to generation of the next reference position signal; and ignition command means for instructing engine ignition at an ignition angle according to the acupressure peak data signal. 1. An ignition timing control device for an internal combustion engine, characterized in that the ignition timing control device retards the ignition angle when the engine is in a fast idle state.