JPH0658114A - Phase difference sensor for internal combustion engine - Google Patents

Abstract

PURPOSE:To provide a phase difference sensor for internal combustion engine which is used to control the intake/discharge air valve timing that drastically decreases the frequency of mis-sensing of phase difference caused by noise. CONSTITUTION:A crank shaft rotational sensor 18 and a cam shaft rotational sensor 19 are respectively connected to input parts 23, 24 of an RS flip-flop circuit 26 through waveform processing units 21, 22 respectively. An output part 25 of the RS flip-flop circuit 26 is connected to the input side of a timing measuring unit 27 for detecting pulse signal intervals, while the output side of the timing measuring unit 27 is connected to a valve timing control unit 28. Accordingly, even if a noise signal caused by noise is generated just after a normal pulse signal is generated from the crank shaft rotational sensor 18, an adjusting signal to be input into the timing measuring unit 27 from the RS flip-flop circuit 26 can not be reversed between high level and low level. Therefore, the pulse signal intervals can not be erroneously detected owing to this noise signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting a rotational phase difference between a crankshaft and a camshaft of an internal combustion engine, and more specifically, an internal combustion engine suitable for controlling intake / exhaust valve timing. The present invention relates to an engine phase difference detection device.

[0002]

2. Description of the Related Art Conventionally, as this type of technique, for example, one disclosed in Japanese Patent Laid-Open No. 59-105911 is known. In this technique, as shown in FIG. 5, a crankshaft rotation sensor 41 that generates a pulse signal for each rotation of the crankshaft and a camshaft rotation sensor 42 that generates a pulse signal for each rotation of the camshaft are respectively provided. It is provided. Then, the two pulse signals generated from the respective sensors 41 and 42 are independently input to different waveform processing units 43 and 44. In each of the waveform processing units 43 and 44, each of the input pulse signals is converted into a digital signal as shown in FIG. 6, and then each of the digital signals is alternately input to the timing measuring unit 45. Then, the timing measuring unit 45
At, the interval between the front and rear pulse signals is captured based on the digital signals alternately input to the timing measurement unit 45. Therefore, the pulse signal interval t3 between the pulse signal P3 from the waveform processing unit 43 and the pulse signal P4 from the waveform processing unit 44 and the pulse signal between the pulse signal P4 and the next pulse signal P3 of the pulse signal P4. Interval t4
Is measured. Further, the timing measuring unit 45 detects the rotational phase difference Δt between the crankshaft and the camshaft based on these pulse signal intervals t3 and t4. That is, the ratio of the pulse signal interval t3 to the sum of the pulse signal interval t3 and the pulse signal interval t4 is detected as the phase difference Δt. Then, the data signal of the phase difference Δt thus detected is output from the timing measuring unit 45 to the valve timing control processing unit. In addition, the valve timing control processing unit is configured to perform control for varying the valve timing of intake and exhaust based on the data signal of the phase difference Δt.

[0003]

However, in the above-mentioned prior art, after the two pulse signals are input into the respective waveform processing sections 43 and 44 and converted into digital signals,
Each digital signal is independent of the timing measurement unit 4
5 is input. That is, signals other than the regular pulse signal such as a noise signal are input to the timing measuring unit 45. Then, the timing measuring section 45 measures the pulse signal intervals of the respective input digital signals.

For example, when the crankshaft rotation sensor 41 picks up noise due to ignition, the crankshaft rotation sensor 41 may generate a noise signal before and after the regular pulse signal. Along with this, as shown in FIG. 6, the timing measurement unit 45 converts the noise signal N digitally converted by the waveform processing unit 43 into a regular pulse signal P.
3 and the pulse signal P4. That is, from the crankshaft rotation sensor 41, the two digital signals of the regular pulse signal P3 and the noise signal N are continuously input.

Therefore, when the control setting is such that all the input signals are regular pulse signals and are alternately input from the respective sensors 41, 42, the pulse signals input later are set. The (noise signal N) may be erroneously recognized as being input from the sensor 42 different from the previous regular pulse signal P3. And, in the case of such erroneous recognition, the pulse signal interval may be detected differently from the regular one.
That is, assuming that the pulse signal interval between the noise signal N and the pulse signal P4 is tN, the phase difference Δt is equal to the pulse signal interval t.
3 and the pulse signal interval tN and the pulse signal interval tN
It is detected based on. Therefore, the phase difference Δt becomes inaccurate, and as a result, the valve timing control may be hindered.

In addition, when signals are continuously input from the same sensors 41 and 42, when the control setting is such that only the pulse signal input later is adopted and the previous pulse signal is canceled. , There is a possibility that only the noise signal N is adopted and the previously input regular signal P3 is canceled. Then, when only the noise signal N is adopted, the phase difference Δt is detected based on the pulse signal intervals tN and t4, and the phase difference Δt becomes inaccurate as in the above case, which in turn leads to the valve timing. There was a risk that control could be hindered.

The present invention has been made in view of the above-mentioned circumstances, and its object is to detect the frequency of erroneous detection due to noise in detecting the rotational phase difference between the crankshaft and the camshaft of the internal combustion engine. An object of the present invention is to provide a phase difference detection device for an internal combustion engine that can be significantly reduced.

[0008]

In order to achieve the above object, according to the present invention, there is provided a phase difference detecting device for an internal combustion engine for detecting a rotational phase difference between a crank shaft and a cam shaft of an internal combustion engine, comprising: First pulse signal generating means for generating a pulse signal for each predetermined rotation of the shaft, and second pulse signal generating means for generating a pulse signal for each predetermined rotation of the cam shaft,
It has one input section for inputting the pulse signal from the first pulse signal generating means and the other input section for inputting the pulse signal from the second pulse signal generating means, and the pulse signal is supplied to each input section. Based on the adjustment signal output from the output adjustment unit that outputs an adjustment signal that is inverted between a high level and a low level each time it is alternately input from one output unit, and the adjustment signal that is output from the output unit of the output adjustment unit, A phase difference detecting device for an internal combustion engine, comprising: an interval measuring means for measuring an interval between a pulse signal from the first pulse signal generating means and a pulse signal from the second pulse signal generating means. It is a summary.

[0009]

According to the above construction, the pulse signal is generated by the first pulse signal generating means every predetermined rotation of the crankshaft, so that the pulse signal is inputted to one input portion of the output adjusting means. . On the other hand, the pulse signal is generated by the second pulse signal generating means at every predetermined rotation of the cam shaft, so that the pulse signal is input to the other input portion of the output adjusting means. At this time, in the output adjusting means, each time the pulse signal is alternately input to each input section, that is,
When the pulse signal from the pulse signal generating means different from the previously input pulse signal is input, the adjustment signal inverted between the high level and the low level is output from one output unit. Then, the interval measuring means measures the interval between the pulse signal of the first pulse signal generating means and the pulse signal of the second pulse signal generating means based on the adjustment signal.

Therefore, even if a noise signal continuous to the pulse signal from the same pulse signal generating means as the previously input pulse signal is input to the same input section of the output adjusting means, the output adjusting means The adjustment signal output from the output section of the is not inverted between the high level and the low level. Therefore, the noise signal is continuously input to the same input unit of the output adjusting unit, so that the interval measuring unit does not erroneously measure the pulse signal interval.

[0011]

【Example】

(First Embodiment) A first embodiment of the phase difference detecting device for an internal combustion engine according to the present invention will be described in detail below with reference to FIGS.

FIG. 1 is a schematic configuration diagram showing a phase difference detecting device used in a variable valve timing device of a V-type engine mounted on a vehicle in this embodiment. Each of the plurality of cylinders of the engine 1 is divided into two left and right positions with the crankshaft 2 as a center, and thereby the left and right banks 3 and 4 are formed. Cam pulleys 7 and 8 are provided at one ends of cam shafts 5 and 6 provided in the banks 3 and 4, respectively. By driving the cam pulley assemblies 7 and 8, the opening / closing timing (valve timing) of an intake valve and an exhaust valve (not shown) that are driven to open / close by the cam shafts 5 and 6 is made variable. .

Each cam pulley assembly 7, 8 has an actuator (not shown) driven by hydraulic pressure built therein. Since the configurations of the cam pulley assemblies 7 and 8 are already known, detailed description thereof will be omitted here.

Further, in this embodiment, a hydraulic circuit 9 for adjusting the supply of hydraulic pressure to each cam pulley assembly 7, 8 is provided. The hydraulic circuit 9 includes oil passages 10A and 10B communicating with the cam pulley assemblies 7 and 8, and an oil tank 1
Hydraulic pump 12 and electromagnetic valve 13 for pressure-feeding hydraulic fluid No. 1
And a pump unit 14 including the above.
The hydraulic pump 12 in this embodiment is the engine 1
It is shared with the so-called oil pump that is installed in advance. As described above, the cam pulley assemblies 7 and 8 and the hydraulic circuit 9 constitute a variable valve timing mechanism (VVT) for varying the valve timing of the banks 3 and 4. Then, the electromagnetic valve 13 drives the pump unit 14, and thereby the cam pulley assemblies 7 and 8 are hydraulically driven. By this drive, a twist is applied between the cam pulley assemblies 7 and 8 and the cam shafts 5 and 6, and the valve timing is adjusted.

A crank pulley 1 is attached to one end of the crank shaft 2.
5 is fixed. A timing belt 16 is mounted between the cam pulley assemblies 7 and 8 and the crank pulley 15, and the cam shafts 5 and 6 are drivingly connected to the crank shaft 2. Further, the engine 1 is provided with idlers 17A, 17B and a tension pulley 17 for applying a required tension to the timing belt 16 mounted thereon.
C is provided.

The engine 1 is provided with a crankshaft rotation sensor 18 as a first pulse signal generating means for generating a pulse signal for each revolution of the crankshaft 2. Further, the right bank 3 of the engine 1 is provided with a cam shaft rotation sensor 19 as second pulse signal generating means for generating a pulse signal for each rotation of the cam shaft 5.

The crankshaft rotation sensor 18 and the camshaft rotation sensor 19 described above are connected to the input side of the controller 20. Further, the electromagnetic valve of the pump unit 14 described above is connected to the output side of the controller 20.

As shown in FIGS. 2 and 3, the controller 20
Are two waveform processing units 21, 22 and two input units 23,
An RS-flip-flop circuit 26 as an output adjusting unit having 24 and one output unit 25, a timing measuring unit 27 as an interval measuring unit, and a valve timing control processing unit 28 are provided. That is, each waveform processing unit 2
A crankshaft rotation sensor 18 and a camshaft rotation sensor 19 are electrically connected to the input sides of 1 and 22, respectively. Further, the output side of each waveform processing unit 21, 22 has two N
The two input sections 23 and 24 of the RS-flip-flop circuit 26 including the AND circuits 26a and 26b are respectively connected. Further, the RS-flip-flop circuit 26
The output unit 25 of is connected to the input side of the timing measuring unit 27. The output side of the timing measuring unit 27 is connected to the input side of the valve timing control processing unit 28. The electromagnetic valve 13 of the pump unit 14 described above is connected to the output side of the valve timing control processing unit 28.

The waveform processing units 21 and 22 are both sensors 18, 1.
The pulse signals input from 9 are shown in FIG.
The digital signal is converted into two types of digital signals of high level and low level as shown in (b).
In addition, the RS-flip-flop circuit 26 includes
Each time a pulse signal is alternately input to 3 and 24, an adjustment signal that is inverted between two levels of high level and low level is output. More specifically, the crankshaft rotation sensor 18 generates a pulse signal each time the crankshaft 2 rotates once. With the generation of this pulse signal, the waveform processing unit 21, which normally outputs a high level signal, outputs a low level signal P1 for a moment as shown in FIG. 3 (a). Further, a pulse signal is generated from the cam shaft rotation sensor 18 every time the cam shaft 5 makes one rotation. With the generation of this pulse signal, the waveform processing unit 22 that normally outputs a high-level signal outputs the signal shown in FIG.
As shown in (b), the low-level signal P2 is output for a moment. Then, from both waveform processing units 21 and 22, RS
-When the alternating low-level signals P1 and P2 are input to the input units 23 and 24 of the flip-flop circuit 26, the output unit 25 of the RS-flip-flop circuit 26 outputs the signals P1 and P2 based on the signals P1 and P2. As shown in FIG. 3C, the adjustment signal that is inverted between the high level and the low level is output. That is, when a signal is input from an input section different from the previously input signal, the output adjustment signal is inverted between a high level and a low level.

Further, the timing measuring section 27 measures the interval between the high level and the low level, ie, the pulse signal intervals t1 and t2, based on the adjustment signal output from the RS-flip-flop circuit 26. It is like this.

In the timing measuring section 27, the ratio of the pulse signal interval t1 to the sum of the pulse signal interval t1 and the pulse signal interval t2 is detected as the phase difference Δt based on the measured pulse signal intervals t1 and t2. . afterwards,
Data regarding the phase difference Δt is sent to the valve timing control processing unit 28. Further, the valve timing control processing unit 28 is adapted to suitably control the electromagnetic valve 13 in order to adjust the valve timing based on the data.

Next, the operation of the phase difference detecting device for an internal combustion engine configured as described above will be described. Each sensor 1
When no noise signal is generated from 8 and 19, both pulse signals from the sensors 18 and 19 are generated alternately. When the alternating low-level signals P1 and P2 are input from the waveform processing sections 21 and 22 to the input sections 23 and 24 of the RS-flip-flop circuit 26, the signals P1 and P1 are input.
Based on P2, the output section 25 of the RS-flip-flop circuit 26 outputs an adjustment signal which is inverted between a high level and a low level. Then, based on the adjustment signal output from the output unit 25 of the RS-flip-flop circuit 26, the pulse signal interval t1,
t2 is measured, and the phase difference Δt is detected based on the intervals t1 and t2. Then, the data regarding the phase difference Δt is sent to the valve timing control processing unit 28.

When a noise signal is generated from the crankshaft rotation sensor 18 due to the ignition noise generated when the ignition plug is ignited, the above-mentioned regular pulse is generated as shown by a broken line in FIG. 3 (a). Signals N1 and N2 equivalent to the signal P1 are input from the waveform processing section 21 to the input section 23 of the RS-flip-flop circuit 26. However, RS
The flip-flop circuit 26 is configured to output an adjustment signal that inverts its adjustment signal between a high level and a low level only when there is an input signal at the input section 24 different from the previous one. ing. Here, since these signals N1 and N2 are input to the same input unit 23 as the input unit 23 of the signal P1 input last time, two adjustment signals are output from the RS-flip-flop circuit 26. Never flip between levels. Therefore, due to the noise-based signals N1 and N2, the pulse signal interval t
1 and t2 cannot be mistakenly captured.

Alternatively, when a noise signal is generated from the camshaft rotation sensor 19 due to ignition noise or the like, it is equivalent to the above-mentioned regular pulse signal P1 as indicated by the broken line in FIG. 3 (b). Signals N3 and N4 from the waveform processing unit 22 to the input unit 2 of the RS-flip-flop circuit 26.
4 is input. However, also in this case, the adjustment signal output from the RS-flip-flop circuit 26 is not inverted between the two levels for the above-mentioned reason. Therefore, even if the signals N3 and N4 caused by noise are input, the pulse signal interval t
1 and t2 cannot be mistakenly captured.

As described above, in this embodiment, even if the signals N1 and N2 and the signals N3 and N4 based on the noise signal are input to the input unit 23 of the RS-flip-flop circuit 26, the timing measuring unit 26 outputs pulses. Signal interval t1,
There is no case where t2 is erroneously measured. Therefore, the frequency of erroneous detection of the phase difference can be significantly reduced as a whole.

Further, in the installation adjustment stage of this phase difference detection device, it is possible to detect in advance the timing of occurrence of the maximum noise among ignition noises that may occur in a plurality of cylinders. Therefore, if it is found that a noise signal due to the maximum ignition noise is generated from the crankshaft rotation sensor 18 in the installation adjustment stage, the timing at which the ignition noise is generated is set to, for example, the signal N1 in FIG. It may be adjusted so that it is equal to the timing. That is, the pulse signal generation timing may be adjusted so that the normal pulse signal from the crankshaft rotation sensor 18 is generated immediately before the maximum ignition noise is generated. By doing so, even if the regular pulse signal and the noise signal resulting from the maximum noise thereof are continuously input to one input unit 23 (or input unit 24) of the RS-flip-flop circuit 26, the output unit It is possible to prevent the adjustment signal output from 25 from being inverted. Therefore, the timing measuring unit 27 does not erroneously detect the pulse signal intervals t1 and t2 based on the maximum ignition noise, and as a result, it is possible to reliably prevent the timing measuring unit 27 from erroneously detecting the phase difference. By the way,
It is possible to further reduce the frequency of occurrence of problems in valve timing control.

In addition, two sensors 1 are used in this embodiment.
The RS-flip-flop circuit 26 having one output section 25 is used in spite of the inputs from 8 and 19. For this reason, in this embodiment, the number of types of signals input to the timing measuring unit 27 can be set to one, and the timing measuring unit 27 includes the waveform processing units 43 and 44.
Different from the conventional technique in which two signals are input from, the number of input ports used in the timing measuring unit 27 is set to 1
You can have only one. Therefore, it is possible to use the timing measuring unit 27 having a small number of input ports, and eventually reduce the cost. Alternatively, a surplus input port provided in advance in the timing measuring unit 27 can be used as another signal input port.

(Second Embodiment) Next, a second embodiment of the phase difference detecting apparatus for an internal combustion engine according to the present invention will be described with reference to FIG. In this embodiment, the same members as those in the first embodiment described above are designated by the same reference numerals, and the description thereof will be omitted. Differences will be mainly described.

In FIG. 4, a first analog switch 31 is provided between the output section 25 of the RS-flip-flop circuit 26 and the timing measuring section 27 in the controller 30. The output side of the waveform processing unit 21 connected to the crankshaft rotation sensor 18 is connected to the input unit 23 of the RS-flip-flop circuit 26, and the second side
It is connected to the input side of the analog switch 32. The output side of the second analog switch 32 is connected between the output side of the first analog switch 31 and the input side of the timing measuring section 27. Further, the output side of the waveform processing section 22 connected to the camshaft rotation sensor 19 is connected to the input section 24 of the RS-flip-flop circuit 26 and the input side of the pulse detection circuit 33. The output side of the pulse detection circuit 33 is connected to the inversion control terminal 31a of the first analog switch 31, and
It is connected to the non-inverting control terminal 32a of the analog switch 32.

The above-mentioned pulse detection circuit 33 is a circuit for detecting the presence / absence of a pulse signal input from the waveform processing section 22. When a pulse signal is input, it outputs a low level signal to input a pulse signal. If there is no signal, it outputs a high level signal. The first analog switch 31 is turned “on” when the signal input from the pulse detection circuit 33 to the inversion control terminal 31 a is at low level, and the signal is transmitted from the RS-flip-flop circuit 26 to the timing measurement unit 27. Is tolerated. Furthermore, the second analog switch 32 is turned “on” when the signal input from the pulse detection circuit 33 to the non-inversion control terminal 32 a is at a high level, and the signal is transmitted from the waveform processing unit 21 to the timing measuring unit 27. It's designed to tolerate.

Further, in this embodiment, the controller 30
Is provided with an EFI control unit 34. A signal equivalent to the signal input to the timing measuring unit 27 is input to the EFI control unit 34, and various fuel injection controls are performed based on this input signal.

Next, the operation of the phase difference detecting device for an internal combustion engine configured as described above will be described. When the crankshaft rotation sensor 18 and the camshaft rotation sensor 19 both operate normally and pulse signals are alternately generated, the pulse detection circuit 33 outputs a low level signal.
Then, the inversion control terminal 31 of the first analog switch 31
a and the non-inverting control terminal 32 of the second analog switch 32
A level signal is input to each a. For this reason,
The second analog switch 32 is turned off, and the signal transmission from the waveform processing section 21 to the timing measuring section 27 is cut off. In addition, the first analog switch 31 is turned “on”, and the signal transmission from the RS-flip-flop circuit 26 to the timing measuring unit 27 is permitted. Therefore, in this case, the timing measuring unit 27 performs the same operation as that of the first embodiment described above, and the phase difference is detected.

When the camshaft rotation sensor 19 fails for some reason and a pulse signal is no longer generated from the camshaft rotation sensor 19, the pulse detection circuit 33 detects this and the pulse detection circuit 33. Outputs a high level signal. Then, a high-level signal is input to each of the inverting control terminal 31a of the first analog switch 31 and the non-inverting control terminal 32a of the second analog switch 32. Therefore, the first analog switch 31 is turned off, and the signal transmission from the RS-flip-flop circuit 26 to the timing measuring unit 27 is cut off. In addition, the second analog switch 32 is turned “on” and the waveform processing unit 2
Signal transmission from 1 to the timing measuring unit 27 is permitted. That is, in this case, the crankshaft rotation sensor 18
Only the pulse signal from is surely input to the EFI control unit 34. Then, in the EFI control unit 34,
The rotation speed of the crankshaft rotation sensor 18 is detected based on the input pulse signal, and fuel injection control is performed according to the speed data.

As described above, in this embodiment, even if the camshaft rotation sensor 19 fails for some reason, only the rotation information of the crankshaft 2 based on the pulse signal from the crankshaft rotation sensor 18 can be reliably obtained. it can. Therefore, based on this rotation information, the EFI control unit 34 can detect the rotation speed of the crankshaft rotation sensor 18, and the fuel injection control can be reliably executed without stopping.

The present invention is not limited to the above-described embodiments, but a part of the structure can be appropriately modified without departing from the gist of the invention and can be carried out as follows. (1) In each of the above-described embodiments, the RS-flip-flop circuit 26 is specifically adopted as the output adjusting means.
A circuit other than the RS-flip-flop may be used as long as it has the same effect as the S-flip-flop circuit 26. Further, although the RS-flip-flop circuit 26 is composed of the two NAND circuits 26a and 26b, it goes without saying that it may be composed of a NOR circuit.

(2) In each of the embodiments described above, the present invention is embodied in the V-type engine 1 and the cam shaft rotation sensor 19 is provided in the right bank 3 of the engine 1. May be provided in the left bank 4. Also,
The present invention may be embodied in an in-line engine.

(3) In each of the above embodiments, each sensor 18,
Although 19 is configured to generate the pulse signal for each rotation of the crankshaft 2 or the camshaft 5, it may be configured to generate the pulse signal for each predetermined rotation angle.

(4) In each of the above embodiments, each sensor 18,
Waveform processing unit 2 for digitizing the signal from 19
1 and 22 are provided, the waveform processing unit 2
A configuration in which 1 and 22 are omitted may be adopted.

[0039]

As described above in detail, according to the present invention, when detecting the rotational phase difference between the crankshaft and the camshaft of the internal combustion engine, the pulse signal generated by the rotation of the crankshaft and the cam crankshaft are detected. The pulse signal generated by the rotation of the output signal is alternately input to the output adjusting means to output the adjusting signal which is inverted between the high level and the low level from the output adjusting means, and the interval measuring means outputs the pulse signal interval. Since this is detected, the excellent effect that the frequency of erroneous detection of the phase difference can be significantly reduced is obtained.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an engine and its phase difference detection device in a first embodiment embodying the present invention.

FIG. 2 is a block diagram showing an electrical configuration of the phase difference detection device in the first embodiment.

FIG. 3 is a timing chart showing a generation state of digital signals output from the waveform processing unit and the RS-flip-flop in the first embodiment.

FIG. 4 is a block diagram showing an electrical configuration of a phase difference detection device according to a second embodiment of the present invention.

FIG. 5 is a block diagram showing an electrical configuration of a phase difference detection device in a conventional example.

FIG. 6 is a timing chart showing a generation state of a digital signal output from the waveform processing unit in the conventional example.

[Explanation of symbols]

1 ... Engine as internal combustion engine, 2 ... Crankshaft, 5,
6 ... Cam shaft, 18 ... Crankshaft rotation sensor as first pulse signal generating means, 19 ... Camshaft rotation sensor as second pulse signal generating means, 23, 24 ... Input section, 2
5 ... Output section, 26 ... RS-flip-flop circuit as output adjusting means, 27 ... Timing measuring section as interval measuring means.

Claims (1)

[Claims] 1. A phase difference detection device for an internal combustion engine for detecting a rotational phase difference between a crankshaft and a camshaft of an internal combustion engine, the first pulse signal generating a pulse signal every predetermined rotation of the crankshaft. Generating means, second pulse signal generating means for generating a pulse signal every predetermined rotation of the cam shaft, one input portion for receiving the pulse signal from the first pulse signal generating means, and the second The other input section for receiving the pulse signal from the pulse signal generating means, and the adjustment signal is inverted between a high level and a low level each time the pulse signal is alternately input to each of the input sections. A pulse signal from the first pulse signal generator based on the adjustment signal output from the output unit of the output adjusting unit, and the second pulse signal. Phase difference detecting apparatus for an internal combustion engine, characterized in that a distance measuring means for measuring the interval between the pulse signals from the raw device.