JPS6235072A - Ignition timing control device in internal combustion engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ignition timing control device for a vehicle-mounted internal combustion engine.

1. A through hole communicating with the combustion chamber is drilled in a member constituting the combustion chamber such as the cylinder head of an on-vehicle internal combustion engine, and a pressure sensor using a piezoelectric element or the like is inserted into the through hole to detect changes in cylinder internal pressure using so-called finger pressure. It can be obtained as a signal.

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 θIC, 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 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. After (hereinafter referred to as ATDC)
) was experimentally confirmed to be between 12° and 13°. Therefore, this ATDCl is set to an ideal crank angle position of 2° to 13°. Therefore, the acupressure peak is A
The ignition timing θ is set to the ideal crank angle position of 12° to 13° TDC. It is desirable to define the IC.

However, even if the ignition timing θI is kept constant, the finger pressure peak changes from moment to moment depending on the engine operating condition, and an ignition timing control device that maintains the finger pressure peak at an optimal position 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 value, and this is used as the actual acupressure peak value to reduce the deviation from the target acupressure peak value. A finger pressure signal response type ignition timing control device that adjusts the ignition angle is considered.

Incidentally, when a vehicle is going down a slope, so-called engine braking is sometimes applied, and it has been found that it is desirable to control the ignition timing so that the engine braking is more effective during such engine braking.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an ignition timing control device responsive to a finger pressure signal that can control the ignition timing so that the engine brake acts more effectively during the engine braking operation.

In the ignition timing control device according to the present invention, when the engine speed is detected and a light load is detected when the engine is rotating at high speed, the ignition timing control device retards the ignition angle by changing the target peak position or cuts the ignition. being done.

Support-1 Figure 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). This includes an acupressure signal generating circuit 1 obtained by closely inserting a pressure sensor such as a piezoelectric element 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 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 Cent
er) 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 acupressure signal at the maximum value after being cleared by the reference position signal, and the comparison 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 latches the count value of the counter 6 every time the peak detection signal from the comparator circuit 5 is supplied to its gate terminal q, while the decoder 11 latches the count value of the counter 6, for example, when the count value of the counter 6 is 63. When this happens, a read command signal is supplied to the ignition angle setting circuit 8. 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 launch contents as peak position information θp× 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 read command signal from the decoder 11. The ignition angle setting circuit 8 is configured by a microprocessor, etc., and receives 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 based on the reference position signal to know the current crank angle value 067, and when this current value θi and the human power θIG match, the ignition switch SW is opened, thereby starting the ignition. transformer T
An ignition current flows through the primary coil of the spark plug (not shown) to ignite the spark plug (not shown).The circuit configurations of the ignition switch SW and the ignition transformer T are merely examples, and various types of ignition can be performed using a trigger signal. The ignition system is well known and will not be described in detail here. Also, the ignition angle setting circuit 8 and the ignition command circuit form an ignition command means. Engine parameters, i.e. engine speed N
e, suction negative pressure Pa, throttle opening degree θtF+, 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 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 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 performing the ignition control operation, the ignition angle setting circuit 8 first sets the ignition angle θIG to the initial value θ! Go is set to wait for a read command signal from the decoder 11, and when the read command signal is received, the lunch contents of the latch circuit 10 are taken in as peak position information θP× (step S+, 82).

Then, this peak position information θpx is the top dead center angle θTl)
In step S3), it is determined whether the sum of c and the angle α of, for example, 12° is greater than or less than, and if it is, the ignition angle θ! G as Δ
Advance the ignition angle by θ (step S4), and if it is smaller, the ignition angle θ! G is retarded by Δθ (step Ss).

Steps S1 to S from the above start to end
The operations of one cycle of No. 5 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 θt in the built-in register is
g is set to θTDC (or a predetermined value) (step 512). Next, the ignition angle data θIG from the ignition angle setting circuit 8 is fetched (step +2) and compared with the current crank angle value θt2, and when the condition of θ = θIC is established, an ignition command is immediately issued (step S++). ,
515), closing the ignition switch SW. On the other hand, θ
If i9≠θIG, add the unit crank angle δθ to θi to prepare for the next program cycle (step 516).
. In step SI4, instead of determining whether θig=θIG, the determination may be made as to whether the difference between 01g and θrc is smaller than δθ.

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.

By the way, in the case of an in-vehicle internal combustion engine, when the vehicle is going down a slope, a situation occurs where torque is transmitted from the wheels to the engine, resulting in so-called engine braking. One idea is to make the engine brake more effective.

FIG. 6 is a flowchart showing an operation program of the ignition angle setting circuit 8 which sets the ignition angle so as to have the function of performing the above operation.

In this operation program, first, engine rotation speed data Ne(
N) with a predetermined threshold Nr (step 520). N
For example, r is 300 Qrpm. Ne (N
) is less than Nr, the crank angle α that determines the target peak position is set to a normal value of, for example, 12° to 16° (step 82+); on the other hand, when Ne (N) exceeds Nr, the throttle angle Compare the degree data H(N) with the threshold value θr (step 522), and θTH(N) is θ
If it is smaller than r, it is determined that the engine is in a braking state, and the crank angle α that determines the target peak position is set to α2, which is larger than α1 (step 523). Ma, Ta, θT)−
If 1(N) is greater than θr, it is determined that the operating state is normal, and α is set to α1 (step 521). Furthermore, in step S22, the engine braking state is detected by comparing θTH(N) and θr, but the absolute value IPs of the intake pipe negative pressure data Pa(N)
It is also possible to compare (H)1 with the pa value pr (step 524). In this case, when lPe (N)l>Pr, it is determined that the engine is in a braking state and α is set to α2 (step 823), and when lPe (N)l<pr, α is set to α1 (step 521).

Next, steps S+ to S5, which are similar to steps S1 to S5 shown in FIG. Since they are exactly the same except for the point that it is made clear that they are sample data values, a detailed explanation will not be given here.

On the other hand, it is also conceivable to fix the set ignition angle θrc to θIGr when an engine brake state is detected (step 525). In this case, steps S2+ and 823 will be omitted. Also, set ignition angle θIG−〇+c
It is also conceivable to set the ignition angle according to the map data value θrG(Ne) corresponding to the engine rotational speed Ne as (Ne).

Furthermore, when an engine braking condition is detected, an ignition prohibition flag is set and supplied to the ignition command circuit 9, and as a function of the ignition command circuit 9, the ignition prohibition flag is set immediately before step S's in the flow of FIG. When a prohibition flag exists, it is also possible to insert a step that bypasses step S+s.

Furthermore, even if the measured peak position θpx (, N) is set to fall within a region including the area before and after the target peak position, a method may also be considered in which the entire area is shifted around the target peak position under engine braking conditions.

As is clear from the above, according to the present invention, the engine braking state is detected by comparing engine parameters with a threshold value, and in that case, the engine ignition angle is adjusted by moving the target peak position, etc. Since the engine brake is delayed or the ignition is cut, the engine brake works better and is preferable.

[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 an operating program of the portion constituted by the microprocessor of the apparatus shown in FIG. 2. FIG. 6 is a flowchart showing an operating mode program of the ignition angle setting circuit according to the present invention. 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 , Indication of the case 1985 Patent Application No. 175178 2 Title of the invention Ignition timing control device for in-vehicle internal combustion engine 3 Person making the amendment Relationship to the case Patent applicant Address 6-27-8 Jingumae, Shibuya-ku, Tokyo Issue name
Name (532) Honda Motor Co. Ltd. 4, Agent 104 5, Date of amendment order Voluntary 6, Number of inventions increased by amendment None-11-\ Proceeding party 11 Seibun) (Spontaneous) 1986 October 30th

Claims (1)

[Claims] (1) A reference position signal generating means that generates a reference position signal every time the engine rotational angular position of the in-vehicle internal combustion engine reaches a reference angular position, a finger pressure signal generating means that generates a finger pressure signal representing the engine cylinder internal pressure, and the criterion of 1. peak position detection means for sequentially generating acupressure peak position data signals representing the maximum peak position of the acupressure signal from the generation of the position pulse to the next reference position pulse; An ignition timing control device for an internal combustion engine, comprising an ignition angle setting means for sequentially setting the ignition angle so as to approach the ignition angle, and an ignition command means for commanding engine ignition at the ignition angle set by the ignition angle setting means, the ignition timing control device comprising: The ignition angle setting means includes a light load state detection means for detecting a light load state of the engine, and an engine high speed rotation detection means for detecting that the engine speed exceeds a predetermined threshold value. An ignition timing control device for an internal combustion engine, characterized in that when the high-speed rotation detecting means detects high-speed engine rotation when detecting a load condition, the ignition angle is further retarded or the ignition is cut.