JPH10111144A - Detecting device of reference position of rotation of crankshaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the precise discrimination of the reference position of a crankshaft by differentiating a plurality of spaces of deformable part with the rest of the spaces, generating positive and negative pulses corresponding to the changes in positive and negative directions in the detection signals of a detecting sensor at the deformable part over separate signal lines, and detecting the space between the positive and negative pulses. SOLUTION: When protrusions 13a to 13c where the spaces between deformable parts are shorter and a protrusion 14 corresponding to the reference position of a crankshaft pass in the vicinity of an electromagnetic pickup 1, detection signals which changes in a positive or negative direction are outputted from the electromagnetic pickup 1. A waveform shaping circuit 6 generates positive or negative pulse signals on the basis of the detection signals and separately supplies them for the input ports PA and PB of a microprocessor 3 via a positive pulse signal line or a negative pulse signal line. The reference position of the crankshaft is discriminated in the microprocessor 3, control signals are outputted from an output port PO to control an ignition device 5, etc., via an output interface 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for detecting a reference rotation position of a crankshaft of an internal combustion engine.

[0002]

2. Description of the Related Art In an internal combustion engine such as an automobile engine,
A rotation reference position of the crankshaft is detected based on a pulse waveform from an electromagnetic pickup cooperating with a signal rotor that rotates in response to the crankshaft, and based on the detection result, an operation stroke of each cylinder is detected. A technique for electronically controlling the fuel injection timing is known.

FIGS. 1 and 2 show an apparatus similar to the apparatus disclosed in Japanese Patent Publication No. 62-20384. In FIG. 1, a rotating member 11 rotates around a rotating shaft 12 in response to a crankshaft (not shown). For example, in the case of a four-cylinder four-cycle engine, the rotating member 11 rotates 360 degrees with respect to 720 degrees of rotation of the crankshaft. Further, in this specification, a portion where the shape changes (rises or falls) in the radial direction of the outer peripheral portion of the rotating member 11 is referred to as a shape change portion. Therefore, the shape change portion in the rotating member 11 refers to the front edge and the rear edge of the protrusions 13a, 13b, 13c, and 14. In this example, the protrusions 13a, 1
The trailing edges of 3b, 13c and 14 are provided at equal angular intervals with respect to the circumferential direction of the rotating member 11. Further, the interval between the two shape changing portions of one protruding portion 14 is different from that of the other 13a,
The protrusions 13b and 13c are longer than the intervals between the shape changing portions, and the protrusions 14 correspond to the reference rotation positions of the crankshaft. The electromagnetic pickup 1 includes these protrusions 13.
a, 13b, 13c, and 14 are fixed so as to be close to and opposite to the rotation trajectory. As the rotating member 11 rotates, the protrusions 13a, 13b, 13c, and 14 pass near the electromagnetic pickup 1. Each time the signal passes, a voltage is generated in the electromagnetic pickup 1 by an electromagnetic induction action, and this voltage becomes a detection signal.

In the waveform shaping circuit 2 shown in FIG. 2, the waveform of this detection signal is shaped into a pulse signal in which the interval between the shape changing portions of the protrusions 13a, 13b, 13c and 14 corresponds to the time interval of the pulse signal. In other words, this pulse signal indicates that the shape change portions of the protrusions 13a, 13b, 13c, and 14 are 2
It is a pulse signal corresponding to the level change part of the pulse signal which is a logical signal of the value. Therefore, by measuring the pulse interval T (N) of the pulse signal, the protrusions 13a, 13
The time when b, 13c, and 14 pass through the electromagnetic pickup 1 can be measured. This pulse signal is input to the input port PI of the microprocessor 3, and a control signal is output from the output port PO of the microprocessor 3 via the output interface 4 to control the ignition device 5 and the like.

[0005] Inside the microprocessor 3, a determination routine shown by a flowchart of FIG. 3 is executed. That is, the microprocessor 3 samples the pulse signal and measures the pulse interval T (N) of the pulse signal (step S21). Next, the current pulse interval T
The ratio of (N) to the previously measured pulse interval T (N-1) is compared with a predetermined value A (step S22). When the value of the ratio is larger than the predetermined value A, it is determined that the protrusion 14 has passed near the magnetic pickup 1 and a reference position has been detected (step S23), and thereafter, the determination routine ends. To return to the main routine (not shown). If the value of the ratio is smaller than the predetermined value A in step S22, it is determined that the protruding portion 13a, 13b or 13c has passed near the electromagnetic pickup 1, and the determination routine ends, and the main routine (FIG. (Not shown).

In the above-described conventional crankshaft rotation reference position detecting device, for example, when rotation unevenness occurs on the crankshaft such as when starting the engine, the rotation unevenness affects the pulse interval of the pulse signal. This makes it impossible to correctly determine the reference rotation position of the crankshaft.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and has as its object the following:
It is an object of the present invention to provide a crankshaft rotation reference position detection device capable of correctly detecting the crankshaft rotation reference position regardless of rotation unevenness.

[0008]

According to the present invention, there is provided a crankshaft rotation reference position detecting device, comprising: a rotating body having a plurality of shape changing portions provided in a rotation direction in response to rotation of a crankshaft; Detection signal generating means provided in the vicinity of the rotation locus of the portion for generating a detection signal that changes in the positive or negative direction each time the shape changing portion passes through the vicinity, and a rotation reference position of the crankshaft based on the detection signal Determining means for determining a rotation reference position of the crankshaft, wherein at least two of the shape change portions correspond to the reference positions and the distance in the rotation direction between the shape change portions corresponds to the shape change. The distance is larger than the distance between the remaining portions of the detection signal, and the determination means outputs a positive pulse and a negative pulse corresponding to a positive change and a negative change of the detection signal to a positive pulse signal line and a negative pulse, respectively. Pulse generating means for separately generating a pulse signal line, and a reference for generating a reference position signal when an interval between the positive pulse and the negative pulse generated on the positive pulse signal line and the negative pulse signal line becomes larger than a predetermined time. And a position signal generating means.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS. FIG. 4 shows a crankshaft rotation reference position detecting device according to an embodiment of the present invention. In addition,
Components corresponding to those of the conventional example shown in FIG. 2 are denoted by the same reference numerals. Projecting portions 13a, 13b, 13
When c and 14 pass near the electromagnetic pickup 1, a detection signal that changes in the positive or negative direction is emitted from the electromagnetic pickup 1. The waveform shaping circuit 6 generates a positive pulse signal or a negative pulse signal based on the detection signal,
These signals are input to the input port PA of the microprocessor 3 via a positive pulse signal line or a negative pulse signal line.
Feed separately to PB. In the microprocessor 3, the reference position of the crankshaft is determined, a control signal is output from the output port PO, and the ignition device 5 and the like are controlled via the output interface 4.

The positive pulse and the negative pulse described above do not mean that the polarity is positive and negative, but indicate that they correspond to the positive change direction and the negative change direction of the detection signal. Furthermore, although the above-mentioned shape change part showed the example formed as the edge of the projection part which turned to the radial direction outside in the direction perpendicular to the rotation direction of the rotating member, the notch which turned to the inside may be sufficient, In short, it is only necessary that the shape change portion is formed so as to extend in a direction different from the rotation direction.

Next, signal generation in the waveform shaping circuit 6 will be described with reference to FIGS. First, when the protrusions 13a, 13b, 13c, and 14 shown in FIG. 7A pass near the electromagnetic pickup 1, a detection signal is issued from the electromagnetic pickup 1 (FIG. 7B). The emitted detection signal is supplied to the waveform shaping circuit 6 shown in FIG. In the waveform shaping circuit 6, only the positive potential portion of the detection signal is extracted by the diode 61 and the resistor R 1 and supplied to the comparator circuit 62. Comparator circuit 6
2 so as to convert the positive potential portion of the detection signal as an analog signal to a logic signal level of the pulse is compared with the input signal level reference level V _r1 (for example, a ground level), when higher than the reference level V _r1 is the high level A signal is output, and a signal of a low level is output when the signal is equal to or lower than the reference level _Vr1 (hereinafter, this logic signal is referred to as a positive pulse (FIG. 7C)).
On the other hand, only the negative potential portion of the detection signal is extracted by the diode 63 and the resistor R2, and the comparator circuit 6
4 is supplied. The comparator circuit 64 outputs a positive potential output only while the level of the negative potential portion of the extracted detection signal is lower than the reference level _Vr2 , and converts the negative potential portion of the detection signal into a logic signal (FIG. 7 (D )). This logic signal is hereinafter referred to as a negative pulse. The negative pulse triggers the one-shot multivibrator 65. The one-shot multivibrator 65 operates to generate a single pulse signal having a predetermined pulse width by using the rising of the supplied negative pulse as a trigger. One-shot multivibrator 65
The pulse signal generated by the above is referred to as an extended pulse (FIG. 7E). The positive pulse and the extension pulse are supplied to each of the input ports PA and PB of the microprocessor 3.

Next, a method of determining the reference position of the crankshaft will be described with reference to FIG. When the protruding portions 13A, 13B, and 13C having a short interval between the shape changing portions shown in FIG. 7A pass near the electromagnetic pickup 1, at the time of the rising edge of the positive pulse shown in FIG. It is understood that the extended pulse shown in E) always exists. However, protrusion 1
When the positive pulse 4 passes, the extension pulse has already disappeared at the rise of the positive pulse (FIGS. 7C and 7E).
reference). Therefore, the extension pulse does not exist when the positive pulse rises only when the shape change portion of the protrusion 14 corresponding to the reference position of the crankshaft passes near the electromagnetic pickup 1. From this, it is possible to determine the reference position of the crankshaft by monitoring the rising of the positive pulse and confirming the signal level of the extension pulse at the time of the rising.

FIG. 8 shows a routine for determining the reference position of the crankshaft in the microprocessor 3. In this routine, first, the rising time of the positive pulse supplied to the PA is detected (step S71). If the positive pulse is not rising, the determination routine ends and the process returns to the main routine (not shown). If the positive pulse is at the rise, move to the next step,
The signal level of the extension pulse supplied to the PB is checked (step S72). If the extension pulse exists, the determination routine ends. If the extension pulse does not exist, it is determined that the crankshaft is at the reference position (step S73), and the determination routine ends and returns to the main routine (not shown). .

In the above-described example, an extended pulse is generated for a negative pulse. However, as another example, an extended pulse is not generated and a delay circuit 66 shown in FIG. A delayed pulse obtained by delaying a negative pulse may be used. That is, as shown in FIG. 7F, the level of PA and PB to which the delay pulse and the positive pulse are supplied can be monitored by using the determination routine of FIG. 8 to know the reference position of the crankshaft.

Further, it is also possible to adopt a configuration using a photoelectric conversion means as shown in FIG. 9 as the detection signal generating means. In FIG. 9, a light beam is emitted from the light emitting element 81 toward the vicinity of the outer periphery of the rotating member 82. The rotating member 82 is made of a material that does not transmit light, and rotates around the rotating shaft 12 that rotates in response to the rotation of the crankshaft. Along the circumference of the rotary member 82 at the radial position where the light beam is irradiated near the outer periphery, the light-passing window 8 for passing the light beam is provided.
3a, 83b, 83c and 84 are provided. The light beams are transmitted through the passing windows 83a, 83b, 8
Only when 3c and 84 pass through the irradiation position of the light beam,
The light is received by the light receiving element 85. The length of the passage window 84 in the circumferential direction is the same as that of the other passage windows 83a, 83b, 83c.
And the time when the light beam passes through the passing window 84 and is received by the light receiving element 85 is longer than the time when the light beam passes through the other passing windows 83a, 83b, and 83c and is received. Becomes The light receiving element 85 generates a signal having a level proportional to the intensity of the incident light, and this signal is differentiated by a differentiating circuit 86 to become a detection signal, which is supplied to the waveform shaping circuit 6.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an electromagnetic pickup and a rotating member.

FIG. 2 is a block diagram showing a conventional example of a crankshaft rotation reference position detecting device.

FIG. 3 is a flowchart showing a conventional determination routine for detecting a rotation reference position of a crankshaft.

FIG. 4 is a block diagram showing a crankshaft rotation reference position detecting device according to the present invention.

FIG. 5 is a block diagram showing a circuit using a one-shot multivibrator in a waveform shaping circuit in the crankshaft rotation reference position detecting device according to the present invention.

FIG. 6 is a block diagram showing a circuit using a delay circuit in a waveform shaping circuit in the crankshaft rotation reference position detecting device according to the present invention.

FIG. 7 is a time chart showing signals in the crankshaft rotation reference position detecting device according to the present invention.

FIG. 8 is a flowchart illustrating a determination routine for determining a rotation reference position of a crankshaft according to the present invention.

FIG. 9 is a perspective view showing a detection signal generating means when an optical means and a differentiating circuit are used in the crankshaft rotation reference position determining apparatus according to the present invention.

[Description of Signs of Main Parts]

 Reference Signs List 1 electromagnetic pickup 6 waveform shaping circuit 13a, 13b, 13c, 14 projecting part and shape changing part 62, 64 comparator circuit for outputting a logic signal 66 one-shot multivibrator 67 delay circuit

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI G01P 3/481 G01P 3/481 D 3/486 3/486 D 3/488 3/488 M

Claims (6)

[Claims] A rotating body responsive to rotation of a crankshaft and having a plurality of shape changing portions provided in the rotation direction;
A detection signal generating unit that is provided in the vicinity of the rotation locus of the shape changing unit and generates a detection signal that changes in a positive or negative direction each time the shape changing unit passes by the vicinity, and a crankshaft based on the detection signal. Discriminating means for discriminating a rotation reference position, comprising: a rotation reference position detection device for a crankshaft, wherein at least two of the shape change portions correspond to the reference position and a distance in the rotation direction between them is: It is larger than the distance between the rest of the shape change portion, the discriminating means, the positive pulse and the negative pulse corresponding to the positive direction change and the negative direction change of the detection signal, the positive pulse signal line and the negative pulse A pulse generating means for separately generating the signal line, and an interval between the positive pulse and the negative pulse generated on the positive pulse signal line and the negative pulse signal line is larger than a predetermined time. And a reference position signal generating means for generating a reference position signal when the crankshaft rotation is detected. 2. The pulse generating means makes pulse widths of the positive pulse and the negative pulse different, and the reference position generating means makes a pulse at an edge of a shorter pulse width of the positive pulse and the negative pulse. 2. The crankshaft rotation reference position detecting device according to claim 1, wherein the reference signal is generated when the other pulse signal level is low. 3. The pulse generation means delays a generation time of any one of the positive pulse and the negative pulse with respect to a change in a positive direction and a change in a negative direction of the detection signal. 2. The crankshaft rotation reference position detection according to claim 1, wherein the reference signal is generated when the other pulse signal level at the edge of the shorter pulse of the positive pulse and the negative pulse is low. apparatus. 4. The shape changing portion is made of a magnetic material,
2. The crankshaft rotation reference position detecting device according to claim 1, wherein said detection signal generating means comprises a coil. 5. The microprocessor according to claim 1, wherein said reference signal generating means has two ports respectively connected to said positive pulse signal line and said negative pulse signal line, and said microprocessor generates said reference signal detection signal in accordance with a potential change of said port. The crankshaft rotation reference position detecting device according to claim 1, wherein: 6. The rotator has an opening for forming the shape change portion, and the detection signal generating means optically detects the opening to generate a corresponding electric signal waveform. 2. The crankshaft rotation reference position detecting device according to claim 1, further comprising a differentiating means for differentiating the electric signal waveform to generate the detection signal.