JPH0419386B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an ignition angle control device for a non-contact ignition device for an internal combustion engine, and in particular to a high-speed rotation ignition control device for stable ignition timing control even when the rotational speed of the internal combustion engine fluctuates. The present invention relates to an ignition angle control device that provides desired high-speed retardation characteristics in the range.

In the above description, the internal combustion engine is abbreviated as an engine, and the device of the above type is called a high-speed retarded ignition angle control device.

An example of an ignition angle control device for a non-contact ignition device for an engine according to the prior art is a device whose configuration and operation are outlined with reference to FIGS. 1 to 3 of the accompanying drawings.

When actually operating an engine, the engine rotational speed may drop suddenly at a rotation angle near compression top dead center, and as a result, the detection timing of the detection signal at the fixed angle position set for the rotating part of the engine may be different from the above. There is a sudden delay in the vicinity of compression top dead center, and in such cases, the ignition angle control device of the non-contact ignition system according to the prior art has a problem in that the actual ignition timing is too advanced from the desired ignition timing. Ta. The present invention has been made with the intention of solving these problems in conventional devices.

An object of the present invention is to replace the use of a single constant current charging circuit in a constant current charging circuit for a capacitor for retardation calculation of an ignition retardation angle signal generation circuit in an ignition angle control device for a non-contact ignition device according to the prior art.
By simultaneously using a second constant current charging circuit that supplies a larger constant current in synchronization with the detection of a predetermined fixed angle position signal during the constant current charging process by the first constant current charging circuit, The transition width in the advance direction of the high-speed retarded ignition timing determined by the terminal voltage of the capacitor being equal to the reference voltage level when the engine rotational speed fluctuates and decreases in the case of the same prior art device. It is an object of the present invention to provide an improved ignition angle control device that can significantly reduce the large transition width in the advancing direction that occurs in the ignition angle.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of a conventional non-contact ignition device for an engine and an ignition advance angle and retard angle control device used therein will be briefly described below with reference to FIGS. 1 to 3 of the accompanying drawings.

FIG. 1 is a schematic diagram of the overall configuration 100 of a known non-contact ignition device for an engine. Reference number 101
is a generator coil of an engine-driven generator, and the AC voltage generated therein is passed through a rectifying element 102 and a primary winding of an ignition coil 105 to a main capacitor 104.
The thyristor 103 is triggered by the output signal from the ignition angle control device 200 generated at the required ignition timing, and the charge in the main capacitor 104 is rapidly discharged through the primary winding of the ignition coil 105. By making the ignition coil 105 2
A high voltage is induced in the next winding, and this high voltage is guided through the spark gap 106 of the engine's spark plug to generate an ignition spark.

FIG. 2 shows the ignition angle control device 20 in FIG.
The specific circuit of 0 is shown in the double-dashed line,
FIG. 3 shows signal waveforms at various parts of the electric circuit shown in FIG. Further, the ignition advance characteristic obtained by the circuit shown in FIG. 2 is represented by the characteristic curve shown in FIG. The engine rotation speed N ₁ shown in FIG. 7 indicates the engine rotation speed at which the signal waveform of FIG. 3 occurs.

1 in Fig. 2 indicates that the rotation of the engine is controlled in order to generate two signals (a set signal and a reset signal) indicating the first fixed angular position θ _H and the second fixed angular position θ _L of the engine, respectively. This is an electromagnetic pickup coil for an angular position sensor that is used in combination with a permanent magnet piece, which is disposed at a position facing a long protrusion provided on the part. A signal generated once per engine revolution in the electromagnetic pickup coil 1 of the angular position sensor (Fig. 3a) is superimposed on the bias voltage provided by the constant voltage power supply V _cc and resistors 2, 3, and 4 and is sent to the comparator. 5 and 6. The positive voltage waveform of this signal waveform is compared with the reference voltage V _a in the comparator 5, and a positive pulse set signal b (FIG. 3b) is generated at the output terminal of the comparator 5, which is applied to the set input terminal s of the flip-flop 7. Sent. On the other hand, the negative direction voltage waveform is the reference voltage V _b in the comparator 6
A positive pulse reset signal c (FIG. 3c) is generated at its output terminal and sent to the reset input terminal R of the flip-flop 7.

A part indicated by the reference number 300, which is a part of the ignition angle control device 200 shown in FIG. 2, is an ignition advance angle signal generation circuit that utilizes the constant current charging and discharging action of the advance angle calculation capacitor 11. The period during which the switch 8 driven by the Q output signal d of the flip-flop 7 (FIG. 3 d) and the switch 12 driven by the output signal of the ignition angle control device 200 (trigger signal of the thyristor 103) are open is as follows. , is a charging period of the capacitor 11 by the constant current i _c1 supplied from the constant voltage power supply V _cc via the constant current charging circuit 10, and the capacitor 11 shown in FIG.
This is shown by the upper right waveform portion of the terminal voltage waveform f. When the Q output signal shown in FIG. 3D is outputted from the flip-flop 7 by the set signal shown in FIG. 3B generated at the first fixed angular position θ _H , the switch 8
The constant current discharge circuit 9 is thereby closed. In the ignition advance angle signal generation circuit 300, circuit constants are selected such that when the switch 12 is open and the switch 8 is closed, the charge in the capacitor 11 is discharged at a discharge rate of a constant current i _d −i _c1 . The discharge voltage waveform of the capacitor 11 at this time is shown by the waveform portion downward to the right in FIG. 3f. The terminal voltage of the capacitor 11 is led to the comparator 13 and compared with the reference voltage V _TH1 , and the output terminal is
The output signal g shown in FIG.

Engine rotation speed at which the signal waveform shown in Figure 3 occurs
N ₁ is in the high-speed retardation region as shown in Figure 7,
At this time, the terminal voltage waveform f of the capacitor 11 does not reach the reference voltage level V _TH1 , so the output signal g of the comparator 13 shown in FIG. 3g remains at a high level continuously. The output signal g of the comparator 13 is applied to the AND circuit 14 together with the output signal m (m in FIG. 3) of the comparator 504 of the ignition retard angle signal generating circuit 500 (described later) and the Q output signal d of the flip-flop 7. At the end, a rectangular wave signal j shown in FIG. 3j is generated. The output signal j of the AND circuit 14 is sent to the OR circuit 1 together with the output reset signal c of the comparator 6 mentioned above.
5 and produces at its output the final output signal k shown in FIG. 3k. output signal k
is the thyristor 1 at its rising angle position θ _F
03, a spark discharge is generated between the sparks 106 in FIG. instantaneously falls to zero volts as shown in FIG. It will be done.
When the engine speed N is in the low speed advance range, the terminal voltage waveform f of the capacitor 11 is the reference voltage V _TH1
, the ignition angle determined by the intersection of the downward-sloping constant current discharge waveform portion of the capacitor 11 and the reference voltage V _TH1 in FIG. So,
The ignition advance characteristic shown in the upper right portion of the characteristic curve in FIG. 7 is obtained.

Next, the ignition retard angle signal generation circuit indicated by the reference number 500 includes a charge/discharge capacitor 50 for retard angle calculation.
3. Power is supplied from a constant voltage power supply V _cc , connected to a charging/discharging capacitor 503, and a constant charging current is supplied to it.
Constant current charging circuit 501 that supplies i _c2 , terminal voltage of capacitor 503 (Fig. 3 l) and reference voltage V _TH2
The comparator 504 receives the input signal c, and the switch 502 is driven by the output signal c of the comparator 6 to short-circuit both ends of the capacitor 503.
When the output signal c of the comparator 6 falls, the switch 502
is opened, and the completely discharged capacitor 503 due to the short circuit between both ends is charged by the constant current i _c2 and its terminal voltage gradually rises to the reference voltage level V _TH2
When the value exceeds , the output m of the comparator 504 becomes high level. As mentioned above, the signal waveform in FIG. 3 indicates a state in which the engine rotational speed is within the high speed retardation region in FIG. 7 (here N ₁ ). In this state, as the engine rotational speed N increases, the slope angle of the charging voltage curve shown in Figure 3 l gradually decreases, so the ignition angle θ _F determined by the intersection between it and the reference voltage level V _TH2 is in the direction of θ _L. to give the required high-speed retardation characteristic (the downward-sloping portion of the characteristic curve in FIG. 7 to the right).

A case will be considered in which the engine rotational speed fluctuates and suddenly decreases near compression top dead center of the engine while the above-described conventional ignition angle control device 200 is operating in the high speed retard operation region. If there is no variation in the engine speed in Figure 4, then the first
The fixed angular position and the second fixed angular position should occupy the positions θ _H and θ _L of the set signal and reset signal shown in broken lines in b and c, respectively, but they shift to the right due to the decrease in engine speed. , to the positions of the set signal and reset signal (θ _H and θ _L ) shown by solid lines in b and c, respectively. At this time, capacitor charging voltage curve l and reference voltage level V _TH2
The ignition angle θ _F determined by the intersection with
approaches the fixed angular position θ _H , resulting in an excessively advanced angle and adversely affecting the engine operating state.

Next, the structure and operation of an ignition angle control device for a non-contact ignition device using the ignition retard angle signal generating circuit according to the present invention will be explained with reference to FIGS. 5 to 8.

FIG. 5 shows a circuit configuration of an ignition angle control device 200 including an ignition retard angle signal generation circuit 400 according to the present invention. In FIG. 5, the circuit configuration of the ignition angle control device 200 according to the prior art including the ignition advance angle signal generation circuit 300 is the same as the circuit configuration of the corresponding portion of the device shown in FIG. The signal waveforms from a to g in FIG. 6 showing the signal waveforms at each part are the same as those from a to g in FIG. 3, so their explanation will be omitted.

FIG. 6 shows a case where the device shown in FIG. 5 is used as an ignition angle control device for a non-contact ignition device of a two-stroke engine, and shows the advance and retard characteristics of the device shown in FIG. It shows signal waveforms of various parts of the circuit operating at engine speed _N1 within the high-speed retardation region of the curve.

Comparing the configuration of the ignition retard angle signal generation circuit 400 according to the present invention in FIG. 5 with the configuration of the ignition retard angle signal generation circuit 500 in FIG. The charging circuit 503 is a constant current charging circuit 5 connected to a constant voltage power supply.
01, but in the circuit of FIG. 5, in addition to the first constant current charging circuit 410 connected between the constant voltage power supply and the retard angle calculation capacitor 403,
Furthermore, it has a second constant current charging circuit 420 connected to the constant voltage power supply, and is connected to the Q output of the flip-flop 7, and is driven when the output signal becomes a high potential to charge the second constant current. The difference is that a switch 401 is provided which operates to connect the output terminal of the charging circuit 420 to the charging terminal of the capacitor 403.

The operation of the ignition retard angle signal generation circuit 400 according to the present invention will now be described with reference to FIGS. 6 through 8, and important differences from the operation of the circuit shown in FIG. 2 will be clarified.

In FIG. 5, the reset signal c sent from the output terminal of the comparator 6 to the reset input terminal R of the flip-flop 7 at the second fixed angular position θ _L is
It is sent in parallel as a drive signal to the switch 402 in the ignition retard angle signal generation circuit 400.
02 is closed to short-circuit both ends of the capacitor 403, and the charge is completely discharged. Reset signal c
falls, the switch 402 opens, and the constant current supplied from the first constant current charging circuit 410
Constant current charging of the capacitor 403 by i _c3 is started, and the terminal voltage of the capacitor 403 rises relatively slowly as shown in FIG. 6h. When the first fixed angular position θ _H is reached, the flip-flop 7 inputs the set signal b and outputs the Q output signal d.
Switch 40 in ignition retard angle signal generation circuit 400
1 is driven by the Q output signal d to close the circuit while it is at a high level, and the first constant current charging circuit 4
In parallel with charging by constant current i _c3 from 10, the second
Constant current from the output terminal of the constant current charging circuit 420 of
i _c4 is supplied to the charging terminal of capacitor 403.
Since the magnitude of the constant current i _c4 is set to be sufficiently larger than the magnitude of the constant current i _c3 , the terminal voltage of the capacitor 403 increases after passing the first fixed angular position θ _H , as shown in FIG. 6h. rises with a large angle of inclination. At the next second fixed angular position θ _L , the Q output signal d from the flip-flop 7 falls to the zero level, and the switch 401 is opened to disconnect the second constant current charging circuit 420 . At the same time, as described above, the reset signal c output by the comparator 6 closes the switch 402, completely discharging the capacitor 403, and initialization is performed.

The terminal voltage of the retard angle calculation capacitor 403 is sent to the input terminal of the comparator 404 together with the reference voltage V _TH2 , and the comparison output signal i shown in FIG.
The comparison output signal i is sent to the input of the AND circuit 14 of the ignition angle control device 200 in FIG.
In the AND circuit 14, the output signal g of the comparator 13, which is another input signal, and the flip-flop 7
An AND operation is performed with the Q output signal d of . The following operation is performed by the ignition angle control device 2 in Fig. 2.
This is as explained for 00.

The overall ignition advance and retard characteristics of the device shown in FIG. 5 described above are expressed by the characteristic curve shown in FIG.

Figure 8 shows that when the engine speed changes within the high speed retardation region, the lower engine speed N ₀
The retardation _{of the} ignition retard angle signal generation circuit 400 of FIG. It shows how the waveform of the charging terminal voltage h of the calculation capacitor 403 and the ignition angle θ _F change.

FIG. 4 shows the charging terminal voltage l of the retard angle calculation capacitor 503 of the ignition retard angle signal generation circuit 500 of the prior art and the charging terminal of the retard angle calculation capacitor 403 of the ignition retard angle signal generation circuit 400 according to the present invention. The voltage h is shown in comparison, and the ignition angle position θ _F based on each is shown to be the same at the steady rotational speed of the engine. Ignition angle θ _F based on charging terminal voltage l of capacitor 503 shown in FIG.
As already explained, an excessive advance angle occurs due to a decrease in engine rotational speed near the compression top dead center. On the other hand, the ignition angle θ _F based on the terminal voltage h of the capacitor 403 in the present invention
When the engine speed decreases and the first fixed angular position θ _H and the second fixed angular position θ _L move from the dashed line position to the solid line position, the ignition angular position θ _F
is also delayed and moves to the right, so (θ _L −θ _F ): (θ _F −
The ratio of θ _H ) does not change significantly before and after the engine speed decreases, that is, the ratio of the ignition angle position θ _F shifting toward the advance direction due to the engine speed decrease can be significantly reduced. Recognize.

FIG. 9 shows another embodiment of an ignition angle control device to which an ignition retard signal generation circuit 400 according to the present invention is applied. The device shown in FIG. 9 does not include the ignition advance angle signal generation circuit 300 shown in FIGS. 2 and 5,
It has a simple configuration as an ignition retard angle control device having only high-speed retard characteristics, and its ignition retard characteristics are represented by the characteristic curve shown in FIG. The device of FIG. 9 can also prevent the adverse effect of a reduction in engine speed on its ignition retard characteristics, as described with reference to FIG. 4.

As clarified by the above explanation, in the ignition angle control device for a non-contact ignition device for an engine to which the ignition retard angle signal generation circuit according to the present invention is applied, the second fixed Charging with the first constant current is started in synchronization with the falling of the angular position, and charging with a second constant current superimposed is further performed in synchronization with the rising of the first fixed angular position signal, and the charging is performed for retard calculation. It is configured to provide desired high-speed retard characteristics by detecting the angular position where the capacitor's charging terminal voltage becomes equal to a predetermined reference voltage and determining the ignition angle, so that the engine rotational speed fluctuates and decreases. Even in such a case, the excellent effect of preventing harmful advances in the ignition angle from occurring can be obtained.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the overall configuration of a known non-contact ignition device for an engine. FIG. 2 is a schematic circuit diagram of the prior art ignition angle control device shown in block form in FIG. FIG. 3 is a signal waveform diagram of each part of the electric circuit of the prior art ignition angle control device shown in FIG. FIG. 4 shows the ignition retard angle signal generation circuit according to the prior art and the ignition retard angle signal generation circuit according to the present invention, each of which is determined by comparing the voltage at the charging terminal of the retard calculation capacitor with a predetermined reference voltage. FIG. 3 is a signal waveform diagram illustrating the influence of a decrease in engine speed on the ignition angle. FIG. 5 is a schematic circuit diagram of an ignition angle control device including an ignition retard angle signal generation circuit according to the present invention. FIG. 6 is a signal waveform diagram of each part of the electric circuit of the ignition angle control device shown in FIG. FIG. 7 is an ignition advance and retard characteristic diagram showing the ignition advance and retard characteristics obtained by the devices shown in FIGS. 2 and 5. FIG. FIG. 8 is a signal waveform diagram showing changes in the charging terminal voltage waveform of the retard angle calculation capacitor of the ignition retard angle signal generating circuit according to the present invention depending on the engine rotation speed. FIG. 9 is a schematic circuit diagram of another embodiment of an ignition angle control device including an ignition retard angle signal generation circuit according to the present invention. FIG. 10 is an ignition retard characteristic diagram showing the ignition retard characteristic obtained by the device shown in FIG. (Explanation of symbols), 1... Electromagnetic pickup coil of angular position sensor, 5, 6, 13, 404, 50
4... Comparator, 7... Flip-flop, 9... Constant current discharging circuit, 10, 410, 420, 501... Constant current charging circuit, 11... Lead angle calculation capacitor, 40
3,503... Capacitor for retard angle calculation, 14...
AND circuit, 15...OR circuit, 100...non-contact ignition device for engine, 101...generator coil of engine drive generator, 103...thyristor, 104...main capacitor, 105...ignition coil, 106...spark gap, 200...ignition angle Control device, 300... Ignition advance angle signal generation circuit, 400, 500... Ignition retard angle signal generation circuit.

Claims (1)

[Scope of Claims] 1. An ignition angle control device for a non-contact ignition device for an internal combustion engine, which detects a first fixed angular position of the internal combustion engine and a second fixed angular position delayed in phase from the first fixed angular position. an angular position sensor that outputs a first fixed angular position signal and a second fixed angular position signal, respectively; a waveform shaping circuit that generates a rectangular wave signal that is displaced from one potential to another potential and then returns to the original one potential at the second fixed angular position; a first constant current charging circuit; a retard calculation capacitor, one end of which is connected to the output end of a constant current charging circuit, and charging is started from the second fixed angle position by the first constant current charging circuit; a second constant current charging circuit; , driven by the output rectangular wave signal of the waveform shaping circuit, electrically conducting between the output terminal of the second constant current charging circuit and the one terminal of the retard angle calculation capacitor, and In parallel with the charging of the retard calculation capacitor by the current charging circuit, the second
a switch circuit for charging the retard calculation capacitor from the first fixed angular position to the second fixed angular position by a constant current charging circuit; a reset circuit that discharges the charged charge; a comparison circuit that compares the terminal voltage of the retard calculation capacitor with the voltage of a predetermined reference signal and generates a rectangular wave signal representing the comparison result; and an output rectangular wave of the comparison circuit. An ignition angle control device for a non-contact ignition device for an internal combustion engine, comprising: a logic circuit that receives a signal and an output rectangular wave signal of the waveform shaping circuit and generates an ignition retard angle signal.