JPH02230911A - Apparatus for controlling opening/closing timing of suction and exhaust valves of internal combustion engine - Google Patents

Abstract

PURPOSE:To eliminate the necessity of a reducing gear or the like to compact a structure by a method wherein opening/closing timing of suction and exhaust valves is advanced and delayed by an electrical means with signals of a crank shaft rotation speed detecting part and a crank pin position detecting part. CONSTITUTION:Signals of a first sensor 10 for generating pulse signals as per specific angle of a rotation of a crank shaft 6 and those of a second sensor 12 for generating a signal as per rotation are shaped so that the position of a crank pin 6a is detected by a counting circuit 13 and an FF circuit 21 and the rotation speed is detected by a counting circuit 15, the counting circuit 14, a memory 22 and a signal holding circuit 23 respectively. Then with signals for opening/closing suction and exhaust valves maintained in a memory unit comprising a second memory 24, decoders 25, 53 and FF circuits 26a to 26h via a third memory 27, first switching circuits 28a to 28d and a second switching circuit 30, current in an open or close direction is flowed from a power supply 33 to valve driving electromagnetic coils 31, 32 to control opening/closing timing of a suction value 2 and an exhaust valve 3.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to an intake and exhaust valve timing control device for controlling an intake and exhaust valve timing control device for an internal combustion engine in accordance with the rotational speed of the internal combustion engine. .

[Prior Art] Conventionally, the opening/closing timing of the intake and exhaust valves of an internal combustion engine is controlled by a cam attached to a rotating shaft driven by the internal combustion engine, and the opening/closing timing of the intake and exhaust valves is determined by the shape of the cam.

At high speeds, there is a large inertial force in the intake and exhaust, so the intake valve is opened from before passing through top dead center to after passing through bottom dead center to lengthen the intake period and increase intake of intake air-fuel mixture. Before passing the bottom dead center, that is, during the explosion process, it opens to allow exhaust gas to be exhausted by its own pressure, and after passing through the top dead center, it opens to some extent to allow exhaust to be exhausted by inertial force.

On the other hand, at low engine speeds, the inertia of the intake and exhaust gases is small, and the combustion and exhaust temperatures are low, so when the intake valve is opened, the exhaust process is still in progress, and the exhaust gas passes through the open intake passage. The intake air mixture enters the intake pipe and exits to the exhaust tube through the open exhaust passage. Therefore, the idling rotation becomes unstable, and the amount of unburned gas (HC) and incompletely combusted gas (Co) in the exhaust gas increases.

Furthermore, since there is no inertia force in the intake air after the bottom dead center and the intake valve is still open even in the compression process, there is a risk that the intake air will flow back into the intake pipe.

Moreover, the maximum combustion temperature is low at low speeds, and the combustion temperature is too low.
When the exhaust valve is opened, a large amount of the unburned gas and the like is also exhausted.

In other words, if the cam shape is determined with emphasis on low-speed rotation, the idle link will be stable, less unburned gas will be emitted, and the output at low-speed rotation will increase, but the output at high-speed rotation will decrease. Also, if you decide on the shape of the cam with emphasis on high-speed rotation,
The output at high speeds increases, but the output at low speeds decreases, the idle link becomes unstable, and emissions of unburned gas, etc. increase. [Problems to be Solved by the Invention] Conventional intake/exhaust valve opening/closing timing control is performed using a cam, so if the shape of the cam is determined with emphasis on low-speed rotation, the output during high-speed rotation will decrease. Furthermore, if the decision was made with emphasis on high-speed rotation, there were problems such as a decrease in output at low-speed rotation, unstable idling, and increased emissions of unburned gas, etc. This invention has been made to solve the above problems, and it controls the opening and closing timing of intake and exhaust valves according to the rotational speed of the internal combustion engine, so that there is no decrease in output from low to high speed rotation, and To provide a compact and inexpensive intake/exhaust valve opening/closing timing control device using electric means, which has a stable idle link during rotation and can reduce the emission of unburned gas.

[Means for Solving the Problems] An intake/exhaust valve opening/closing timing control device for an internal combustion engine according to the present invention includes: a first sensor that generates a large number of signals with one rotation of a signal generating rotary body driven by a crankshaft; a second sensor that generates one signal with one rotation of the signal generating rotating body;
a crank pin position detection section that detects the position of the crank pin based on signals from the sensor and the second sensor and generates an output signal; and a crank pin position detection section that detects the rotational speed of the crankshaft based on the signals from the first sensor and the second sensor. a crankshaft rotational speed detection section that generates an output signal; and a memory section for intake and exhaust valve opening/closing signals that outputs the output timing of the output signal of the crank pin position detection section that is adapted to the output signal of the crankshaft rotational speed detection section. and a switching circuit that receives the intake/exhaust valve opening/closing signal read from the memory section and closes the circuit of the valve drive electromagnetic coil.

[Function] The intake and exhaust valves of the present invention have a compact structure that does not require any reduction gears, etc., since the opening and closing timings thereof are controlled by electrical means in accordance with the rotational speed of the internal combustion engine, and the intake and exhaust valves of the present invention have a compact structure that does not require any reduction gears, There is no reduction in output up to high speed rotation. In addition, the idle link can be stabilized during low-speed rotation, and emissions of unburned gas and the like can be reduced.

[Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic diagram of an intake/exhaust valve opening/closing timing control device according to the present invention, and will be explained using the first cylinder among four cylinders as an example.

In this figure, reference numeral 1 indicates a cylinder constituting one cylinder; 2 and 3 indicate an intake valve and an exhaust valve provided at the top of cylinder 1; 4 indicates a piston that moves up and down within cylinder 1;
is a link mechanism that rotates the crankshaft 6 by the vertical movement of the piston 4, and a connecting pin 6a between the link mechanism 5 and the crankshaft 6 is a crank pin.

Reference numeral 7 denotes a signal generating rotor having, for example, 512 convex portions 8 at approximately equal intervals on its circumferential surface and one convex portion 9 on the side surface, and is driven clockwise with respect to the crankshaft 6; 10 denotes a movement locus of the convex portions 8; The first sensor 10 is disposed at the top dead center opposite to the first sensor 10 , and this first sensor 10 generates 512 pulse signals in one rotation of the signal generating rotating body 7 and supplies them to the waveform amplification shaping circuit 11 . 12
is a second sensor disposed close to the moving locus of the convex portion 9, and this second sensor 12
Waveform amplification shaping circuit 1 generates one pulse signal by rotation
The second sensor 12 is arranged so that the signal from the second sensor 12 is generated on the advance side of the top dead center by 60 pulse signals.

14 is a counting circuit that counts the number of output pulses of the waveform amplification shaping circuit 11 based on the output signal of the first sensor 10, and the illustrated example is composed of three counters 14a to 14c.

Reference numeral 15 denotes a timing circuit that starts a timing operation using the output pulse of the waveform amplification shaping circuit 13 as a reference signal based on the output signal of the second sensor 12, and outputs a signal at each specific clock time. A flip-flop 16 which is set by the output pulse of the amplifier circuit 13 and a 100K
A crystal oscillation circuit 17 that oscillates at Hz, and three counters 19 that input the Q signal of the flip-flop 16 as a reset signal and count the output pulses of the crystal oscillation circuit 17.
a to 19c, and an AND circuit 2o which outputs a signal at specific time intervals based on the AND of the output signals of the counters 19a to 19c.

2l is a flip-flop as a frequency dividing circuit that divides the output pulse of the waveform amplification shaping circuit 13 into 1/2, and when the output of this flip-flop 2l is "0", it is the first rotation of the crankshaft 6. When the output is "1", it indicates the second rotation of the crankshaft 6, and the crank pin position is indicated by the output of the counting circuit 14 and both outputs.

Reference numeral 22 denotes a first memory which inputs the counted values of the counters 14a to 14c and sequentially reads out output signals of 32 stages stored in advance. The AND circuit constant is 640 counts, that is, the clock time is 0. FIG. 2 shows part of the stored contents of the first memory 22 when the time is 0064 seconds.

Reference numeral 23 denotes a signal holding circuit that holds an output signal corresponding to the rotational speed of the crankshaft 6 read from the first memory 22 based on the output signal of the AND circuit 20 output at specific time intervals, and outputs the held signal. The illustrated example is composed of two latch circuits 23a and 23b. 24 is a crank pin position detection signal consisting of the crankshaft rotational speed detection signal outputted from the signal holding circuit 23, the output of the counting circuit 14, and the "0" or "1" output signal of the frequency dividing circuit 21. This is a second memory that outputs intake/exhaust valve opening/closing signals stored in advance based on the angle and retard characteristic switching signals.

A decoder 25 inputs the output signal of the second memory 24, and a total of 16 output terminals are provided on the output side of the decoder 25 to connect the set terminals and reset terminals of the eight flip-flops 26a to 26h. ing.

27 is a third memory 28a which inputs the output signal of the signal holding circuit 23 corresponding to the rotational speed of the crankshaft 6 and selectively outputs a four-stage signal stored in advance;
~28d receives the output signal of the third memory 27 and becomes conductive;
Resistors 29a to 29d with different resistance values in the power supply circuit
30 is a second switching circuit that conducts in response to the output signals of the flip-flops 268 to 26h and causes current to flow in the closing or opening direction to the valve drive electromagnetic coils 31 and 32. The switching circuit 30 includes a large number of transistors Tri to Trio.
and a resistor R.

A power source 33 is composed of a battery 34 and an electromagnetic coil 37 that receives power from the battery 34 via a key switch 35 and a backflow prevention diode 38 and closes a power switch 36 when the engine is started.

In addition, the waveform amplification shaping circuit 11.13 and the counting circuit 14
, the flip-flop 2l constitutes a crank pin position detection section that detects the position of the crank pin 6a. Further, the waveform amplification and shaping circuits 11 and 13, the counting circuit 14, the clock circuit 15, the first memory 22, and the signal holding circuit 23 constitute a crankshaft rotational speed detection section. In addition, the second
Memory 24, decoders 25, 53, flip-flop 2
6a to 26h constitute a memory section for intake/exhaust valve opening/closing signals.

FIG. 3 shows the configuration of the intake valve 2. A magnet 42 is attached to one end of a valve shaft 41, a yoke 43 is provided to surround this magnet 42, and a valve driving electromagnetic valve coil 31 is attached to the outer periphery of this yoke 43. is wrapped around it. Further, a stopper 45 made of an elastic material such as rubber is provided in the middle of the valve shaft 41 in contact with the bearing 44 to regulate the opening amount of the intake valve 2 . The exhaust valve 3 has the same configuration as the intake valve 2, so a description thereof will be omitted.

Next, a description will be given of how the crankshaft rotational speed signal is stored in the second memory 24. The explosion order is 1-3-
The rotational speed of the crankshaft 6 of the 4-cylinder engine 4-2 is 1
Divided into 30 stages, with 1 stage below 000 and 30 stages from 1000 to 7000, changing the stage every time the number of revolutions increases by 200.
There are 32 levels, including one level of 7,000 or more.

As mentioned above, the signal of the second sensor 12 is arranged so that it is generated on the advance side by the amount of 60 pulse signals generated by the first sensor from the top dead center. The value obtained by subtracting the above number of stages is used as the advance angle and retard angle amount, and 3 of the above number of stages is added to the 60 pulse signals mentioned above.
The second memory 24 uses the added value as the retard angle and advance angle amount.
It is something to remember.

In other words, when the rotational speed of the crankshaft 6 is too low or less, the minimum advance amount of the first cylinder's intake valve opening is 60-11=59. The minimum retard amount for closing the intake valve is 256+60+3=3 19. The reason why 256 is added here is that the intake valve closes after the crankshaft 6 has rotated half a revolution after the intake valve opens.

In addition, the maximum advance angle of the intake valve is 60-32=28, and the maximum retardation amount of the intake valve is 256+60+96=4 1 2, and for each case, the minimum advance angle, minimum retard angle, maximum advance angle of the intake and exhaust valve opening/closing, The maximum retard angle is summarized as shown in Fig. 4.

In addition, in Figure 4, "0" and "l" placed before the count number
Since a 4-cycle engine completes one cycle with two rotations of the crankshaft 6, the numerical value ``'' is used to distinguish between those that operate during the first rotation and those that operate during the second rotation. , these "0" and rlJ signals utilize the "0" and "1" output signals of the frequency dividing circuit 21.

Next, the memory section for the intake and exhaust valve opening/closing signals will be explained. The lower nine address terminals of the second memory 24 are connected to the crank pin position detection signal, that is, the output terminal of the counting circuit 14, and the lower 11th to IS address terminals are connected to the crankshaft rotation speed detection signal, that is, the latch circuit 23. output terminal is connected. When these signals are present, the second memory 24
outputs a pre-stored signal. This signal becomes an intake/exhaust valve opening/closing signal, and the decoders 53, 25 actuate the flop flips 26a to 26h to open/close a predetermined intake/exhaust valve.

Now, if the crankshaft rotational speed is less than 100 orpm, the first stage of the crankshaft rotational speed detection signal is input to the address terminal of the second memory 24, and when the crankpin position detection signal reaches 59 counts of the first rotation, the first stage of the crankshaft rotational speed detection signal is inputted to the address terminal of the second memory 24. The intake valve open signal for one cylinder is output to the output terminal of the second memory 24.

In addition, the closing signal of the intake valve of the first cylinder is 319 counts of the first rotation, the opening signal of the exhaust valve of the first cylinder is 313 counts of the second rotation, and the closing signal is the count of 319 of the first rotation of the next cycle. The count is 61, and this first stage is the minimum advance/retard angle.

Next, when the speed reaches 1000rpa+, the opening signal of the intake valve of the first cylinder is 58 counts of the first rotation, and the closing signal is 1
This is a count of 322 rotations. The open signal for the exhaust valve of the first cylinder is 310 counts in the second rotation, and the close signal is 62 counts in the first rotation of the next cycle, which is a count that has changed by one step.

Note that when the count number decreases, the angle is advanced, and when it increases, the angle is retarded.

In this way, each time the intake/exhaust valve opening/closing signal changes by one step, the crank pin position can be changed and output to match the crankshaft rotation speed, and the crankshaft rotation speed can be changed in 32 steps from less than 1000 rpm to more than 700 rpm. can be varied over a period of time.

The change in the intake valve open signal and the exhaust valve close signal is one count in one step, and the change in the intake valve close signal and the exhaust valve open signal is three counts in one step.

Next, the operation will be explained. The crankshaft 6 is driven by a drive source (not shown) started by operating the key switch 35.
When the crankshaft 6 is driven to rotate, the signal generating rotating body 7 also rotates together with the crankshaft 6.

Therefore, the first sensor 10
Outputs a signal each time it passes. This signal is shaped into a pulse signal by the waveform amplification shaping circuit 11, counted by the counting circuit 14, and the counted circle is supplied to the first memory 22 as soon as it is completed.

On the other hand, the second sensor 12 outputs a signal when the convex portion 9 passes each rotation of the signal generating rotating body 7. This signal is shaped into a pulse signal by the waveform amplification shaping circuit 13, and this pulse signal resets the counting circuit 14 and sets the flip-flop 16. Therefore, the counting circuit 14 is cleared to the count value "0" every revolution of the signal generating rotating body 7, and starts a new counting operation.

The clock circuit 15 counts the output pulses of the crystal oscillator circuit 17 with counters 19a to 19c, and when a specific time comes, the AND circuit 20 inputting the outputs of the counters 19a to 19c performs a logical product and generates an output signal.

This output signal resets the flip-flop l6,
The Q output of the flip-flop 16 resets the timer circuit 15 to stop the timer operation.

The first memory 22 receives the output of the counting circuit 14 as an input.
The latch circuit 23 holds the outputs sequentially read from the AND circuit 20 using the output signal of the AND circuit 20, and this holding signal becomes the rotational speed of the crankshaft at that time.

Then, when the signal generating rotating body 7, which has rotated once together with the crankshaft 6, enters the second rotation, and the convex portion 9 again passes the position opposite to the second sensor 12, based on the output signal of the second sensor 12, the waveform The output pulse of the amplification shaping circuit 13 inverts the Q terminal output of the frequency dividing circuit 21 from "0" to "1" and resets the counting circuit 14 again.

Now, if the rotational speed of the crankshaft 6 is 1000 or less, when the count value of the counting circuit 14 becomes "59",
An intake valve opening signal for the first cylinder is output from the second memory.

Then, the output of the second memory 24 is determined by the decoder 25 and the decoder 53, and a determination signal is supplied to the set terminal S of the flip-flop 26a that opens the intake valve 2 of the first cylinder. Therefore, an output is generated at the terminal of the flip-flop 26a, and this output signal makes the transistor Tri of the second switch circuit 30 conductive.

On the other hand, when the key switch 35 is operated, the diode 3
The electromagnet coil 37 is energized and excited by the battery 34 via the crankshaft 6, and the power switch 36 is closed. coil 3
7 is energized and kept the power switch 36 closed. Therefore, when the transistor Tri becomes conductive,
Battery 34 - Key switch 35 - Power switch 36 - First switching circuit 28 - Resistor 29 - Transistors Tr1 to Tr3 of the second switching circuit 30 - Diode 38 - Valve drive electromagnetic coil 31 that controls the intake valve 2 of the first cylinder. A current flows in the direction of the solid line arrow in the path of the transistors Tr4 and Tr5 of the circuit 30, and the intake valve 2 is opened.

Further, when the count value of the counting circuit l4, which is the crank pin position detection signal, reaches r3 1 9 J and the intake valve closing signal for the first cylinder is read out from the second memory 24, the output of the second memory 24 is The determined signal from the decoder 25 to close the intake valve 2 of the first cylinder is supplied to the reset terminal R of the flip-flop 26a and held. The transistor Tr6 of the second switch circuit 30 is made conductive by the output signal of the Q terminal of the flip-flop 26a.

Due to the conduction of this transistor Tr6, the battery 34
- Key switch 35 - Power switch 36 - First switching circuit 28 - Resistor 29 - Transistors Tr6 to Tr8 of second switching circuit 30 - Diode 38 - Valve drive electromagnetic coil 3l All transistors Tr9, T of circuit 30
A current flows in the direction of the dotted line arrow through the r 1 0 path, and the intake valve 2 is closed.

Hereinafter, based on the crank pin position detection signal consisting of the output signal of the frequency dividing circuit 21 and the output signal of the counting circuit 14, which change according to the first and second rotations of the crankshaft 600, the intake and exhaust valves of the first to fourth cylinders are The opening/closing signal is output via the second memory 24 and decoder 25 every time the crank pin reaches a predetermined position, and sequentially operates the flip-flops 26a to 26h to open and close the intake and exhaust valves of each cylinder.

In addition, if the second sensor 12 is also provided at the symmetrical chain line position 12a and is switched to the one provided at the solid line position using a changeover switch (not shown), the reverse rotation of the crankshaft 6 can be easily controlled. It can be carried out.

In FIG. 1, reference numeral 39 denotes a lead angle/retard angle characteristic changeover switch, and by opening or closing this switch, the lead angle/retard angle characteristic of the contents stored in the second memory 24 is changed into two stages via a resistor 40. be.

FIG. 5 shows another embodiment of the present invention, in which the first embodiment described above is shown.
In the embodiment shown in the figure, the rotational speed of the crankshaft is determined based on the number of counts of the counting circuit 14 between the signals output from the clock circuit 15 at fixed time intervals, but this embodiment is the opposite. This is what I did.

In other words, the counters 14a to 14 forming the counting circuit 14
The output of c is input to the AND circuit 47, and the rotational speed of the crankshaft is determined based on the time required for the logical product of the AND circuit 47 to reach a predetermined count value, which is similar to the above embodiment. It has the action and effect of

In addition, in this example in FIG. 5, the first sensor 10, the second
As the sensor 12, a photocoupler 48 consisting of a light emitting source and a light receiving element arranged opposite to each other on both sides of the signal generating rotating body 7 is used.
, 49, and the signal generating body 7 is provided with holes 50 at regular intervals and one hole 51 instead of the convex portion 8.9, and the signal generating body 7 is provided with holes 50 at regular intervals and one hole 51, and the signal is generated according to the rotation of the signal generating rotary body 7, as in the above embodiment. can occur.

FIG. 6 shows an example in which a counting circuit 52 is used in place of the frequency dividing circuit 2l in each of the above embodiments. The same effect as the case using the circumferential circuit 21 is achieved.

Each of the above embodiments shows the case of a four-cylinder engine, but in the case of four or more cylinders, decoders 25a to 25d corresponding to the decoder 25 are added depending on the number of cylinders, and a second
Which decoder 25, 25 is selected depending on the output signal of the memory 24?
If a decoder 53 is provided to select whether to operate a to 25d, the same effects as in each of the embodiments described above can be achieved.

[Effects of the Invention] As described above, according to the present invention, the intake valve and the The opening/closing timing of the exhaust valve is electrically advanced or retarded according to the rotational speed of the internal combustion engine, resulting in a compact configuration that does not require any reduction gears, etc., and improves output. You can expect improved fuel efficiency. By switching the advance angle and retard angle characteristics to emphasize fuel efficiency and output, it is possible to easily perform control that emphasizes fuel efficiency and output.

Gasoline engines can reduce Co and HC.

HO. Even if the output is reduced by lowering the compression ratio as a countermeasure, the output can be easily increased by that amount, so that effects such as easier NOx countermeasures can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing an intake/exhaust valve opening/closing control device according to an embodiment of the present invention, Fig. 2 is a diagram of the contents stored in the first memory, Fig. 3 is a configuration diagram of the intake valve, and Fig. 4 is an advance angle diagram. 5 and 6 are partial block diagrams showing other embodiments of the device of the present invention. 2... Intake valve, 3... Exhaust valve, 6... Crankshaft, 7... Signal generating rotating body, 8, 9... Convex portion, 10...
...First sensor, 12...Second sensor, l4...Counting circuit, 15...Clock circuit, 21...Frequency dividing circuit, 2
2... first memory, 23... signal holding circuit, 24...
...Second memory, 25...Decoder, 26a to 26h
...Flip-flop, 30...Switching circuit. (a) Figure (b)

Claims (6)

[Claims] (1) A first sensor that generates a large number of signals with one revolution of a signal-generating rotary body driven by a crankshaft; a second sensor that generates one signal with one revolution of the signal-generating rotary body; a crank pin position detection section that detects the position of the crank pin based on signals from the sensor and the second sensor and generates an output signal; and a crank pin position detection section that detects the rotational speed of the crankshaft based on the signals from the first sensor and the second sensor. a crankshaft rotational speed detection section that generates an output signal; and a memory section for intake and exhaust valve opening/closing signals that outputs the output timing of the output signal of the crank pin position detection section that is adapted to the output signal of the crankshaft rotational speed detection section. An intake/exhaust valve opening/closing timing control device for an internal combustion engine, comprising: a switching circuit that receives an intake/exhaust valve opening/closing signal read from the memory section and closes a circuit of a valve drive electromagnetic coil. (2) A means for generating a signal according to the rotation of the signal generating rotary body is provided by a plurality of convex portions formed at approximately equal intervals on the circumferential surface of the signal generating rotary body, one convex portion formed on the side surface, and the convex portion. 2. The intake/exhaust valve opening/closing timing control device according to claim 1, wherein the control is performed by a sensor installed opposite to the movement locus of the intake/exhaust valve opening/closing timing. (3) A photocoupler in which a means for generating a signal according to the rotation of the signal-generating rotary body is disposed on both sides of the signal-generating rotary body, a plurality of holes formed at regular intervals, and one other hole. 2. The intake/exhaust valve opening/closing timing control device according to claim 1, wherein the control is performed by:. (4) The intake/exhaust valve opening/closing timing control according to claim 1, wherein the rotational speed of the crankshaft is determined based on how many counts the counting circuit has between signals output from the timing circuit at fixed time intervals. Device. (5) The rotational speed of the crankshaft is determined by using the output of the counter constituting the counting circuit as the input of the AND circuit, and the time required for the logical product of the AND circuit to reach a predetermined count value. The intake/exhaust valve opening/closing timing control device according to claim 1. (6) The intake/exhaust valve opening/closing timing control device according to claim 1, wherein the crank pin position detection signal is detected at the first or second rotation of the crankshaft using only a counting circuit.