JPH0252966B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotational position detection device for an internal combustion engine for an automobile.

BACKGROUND ART Conventionally, in response to various demands for internal combustion engines for automobiles, proposals have been made to electrically control internal combustion engines. For this purpose, various sensors are required to constantly detect the state of the internal combustion engine. Among these, the rotational position detection device is an important sensor for determining the ignition timing, operating speed, etc. of the internal combustion engine. To this end, the present invention provides a rotational position detection device that operates accurately and reliably.

Therefore, the present invention provides a method for detecting reference position information by detecting each information of a rotating body using a plurality of sensors, which forms a large number of angle information and rotation reference position information obtained by omitting part of the angle information. A periodic signal representing a tooth gap is generated by shifting the position of the tooth gap, and the position of the tooth gap is detected to generate a reference position output, and the sum of the output signals of each sensor is calculated. By generating a perfect angular position output, by using only a rotating body with some of the angular information missing, it is possible to achieve a perfect angular position output and a reference position output. The purpose is to obtain it with high accuracy.

The present invention will be described below with reference to embodiments shown in the drawings. In Figures 1 to 3, Figure 2 shows the mechanical configuration of the rotation detection part, in which a large number of magnetic poles corresponding to angle information are magnetized, and the part corresponding to reference information is shown in Figure 3. As shown, a missing disc 30 constituting a rotating body is fixed to the shaft 24 with screws via the fixing disc 22. This shaft 24 is driven by an internal combustion engine in synchronization with the rotation of the internal combustion engine. Further, first and second angle sensors 40 and 50 each made of a magnetoresistive element are arranged facing each other on the outer periphery of the disk 30. Also,
Each sensor 40, 50 is arranged within the detection head H at a position shifted by a predetermined angle on substantially the same plane.
As shown by a and b in the figure, alternating current outputs are generated that are substantially in phase and are shifted in position. In addition, FIG. 1 shows the circuit configuration, in which resistors 61 to 64,
A first waveform shaping circuit 60 consisting of an adjustment resistor 65 and a comparator 66, an AND circuit 700, an inverter 701, a NAND circuit 702, and NAND circuits 703 and 70 forming a flip-flop circuit.
4, a second waveform shaping circuit 80 consisting of resistors 81 to 84, an adjustment resistor 85, and a comparator 86, a capacitor 121, and a resistor 122.
The angle differential circuit 12 includes a diode 123, and the reference differential circuit 13 includes a capacitor 131, a resistor 132, and a diode 133. 9a is a reference signal output terminal, 11
a is an angle signal output terminal. In the figure, + is connected to the positive terminal of the constant voltage power supply. and,
The input operation level of the first waveform shaping circuit 60 is the fourth
The resistance value of the adjustment resistor 65 is adjusted so that La shown in FIG. 4 is obtained, and the a waveform of the first angle sensor 40 shown in FIG. Shape the waveform into a rectangular wave. Further, the resistance value of the adjustment resistor 85 is adjusted so that the input operation level of the second waveform shaping circuit 80 becomes a positive value slightly higher than the Lb level shown in FIG.
The waveform b of the second angle sensor 50 shown in FIG. 4 is shaped into a rectangular wave having gaps at predetermined positions, such as the waveform d shown in FIG. The outputs of the waveform shaping circuits 60 and 80 are input to an AND circuit 700, and the output thereof becomes a perfectly square wave as shown in FIG. 4e. Therefore, the NAND circuit 70
The output waveform of the second waveform shaping circuit 80 is as shown in f in FIG. It is reset by the fall of the signal, and the NAND circuit 703 generates an output as shown by g in FIG. And AND circuit 70
The rising edge of the output signal of 0 is differentiated by the angle differentiating circuit 12, and a differential signal is generated at the angle signal output terminal 11a as shown by h in FIG. 4, and the point in time at which each differential signal is generated becomes an angular position. Further, the rising edge of the output signal of the flip-flop circuit is differentiated by the reference differentiating circuit 13, and the reference signal output terminal 9
A differential signal is generated at point a as indicated by i in FIG. 4, and the time point at which this differential signal is generated becomes the reference position.
In the circuit shown in FIG. 1, it goes without saying that the differentiating circuits 12 and 13 can be omitted by using a subsequent circuit that is triggered by the rise of the output signal.

In the embodiment described above, the angle sensors 40 and 50 are configured to generate AC outputs having approximately the same phase, but AC outputs having approximately the opposite phase may be generated.

Furthermore, in the above-described embodiment, the rising edge of the first waveform shaping circuit was defined as the angular position, and the falling edge of the first waveform shaping circuit was defined as the reference position. Of course, the falling edge of the first waveform shaping circuit is the angular position, and the rising edge of the second waveform shaping circuit is the reference position.

As described above, in the present invention, a plurality of sensors detect each piece of information about a rotating body, which forms a large amount of angle information and rotation reference position information obtained by omitting some of the angle information, and then position the rotation body at the reference position. When information is detected, a periodic signal that is missing is generated by shifting the position where the missing tooth occurs, and the position where the missing tooth is detected is generated to generate a reference position output, and the output signal of each sensor is Since a perfect angular position output is generated by calculating the sum of It has the excellent effect of being able to obtain the following in a good manner and with high precision.

[Brief explanation of the drawing]

Fig. 1 is an electric circuit diagram showing one embodiment of the device of the present invention, Fig. 2 is a perspective view schematically showing the mechanical configuration of the rotation detecting part in the device shown in Fig. 1, and Fig. 3 is the diagram shown in Fig. 2. FIG. 4 is a magnetization state diagram of the rotation detecting portion, and FIG. 4 is a waveform diagram of each part for explaining the operation of the apparatus shown in FIG. 30... Disc constituting the rotating body, 40... First
angle sensor, 50... second angle sensor, 6
0, 80, 700...first and second waveform shaping circuits constituting the angular position detection circuit, AND circuit, 70
1 to 704...Inverters and NAND circuits forming the reference position detection circuit.

Claims (1)

[Claims] 1 A rotating body in which a large number of angle information representing rotation angles are formed at equal intervals on the circumference, some of which are omitted to serve as rotation reference position information, and an integer of the angle information is formed along the circumference of the rotating body. They are lined up at twice the arrangement spacing, and when the presence of the angle information and the reference information are detected, and the reference position information is detected, periodic signals that are missing are generated. An angle sensor, first and second waveform shaping circuits that shape the synchronous signals of each of these angle sensors into binary signals according to the presence of the angle information and reference information, and these first and second waveform shaping circuits.
The binary signals from the first and second waveform shaping circuits are input, and the position where one of the binary signals from the first and second waveform shaping circuits continues to be output and the other is missing is detected and set as a reference. A reference position detection circuit including a NAND circuit and a flip-flop that generates a signal, and a logic circuit that generates a perfect angular position output by summing the output signals of the first and second waveform shaping circuits. Rotational angle position detection device for internal combustion engines.