JPH01280663A - Crank position detecting device - Google Patents

Abstract

PURPOSE:To increase a subsequent output on the delay angle side and to improve detecting precision without being influenced by a noise, by a method wherein the clearance of a pulse detecting member on the delay angle side responding to a magnetic sensor is increased to a value higher than that of a pulse detecting member on the advance angle side. CONSTITUTION:With a rotor 1 mounted on the crank shaft of an engine rotated, a magnetic sensor 2 generates a crank position detecting signal in synchronism with the rotation to input it to a control means 3. In which case, since an ignition coil 11 is controlled through a power transistor 10 by a control means 3, an ignition plug 13 of a given cylinder is selectively controlled through a distributor 12. In this case, regarding protrusions E and D on the advance angle side and the delay angle side formed on a crank position detecting part 1a of the rotor 1 at a given angle theta, the protrusion D on the delay angle side is set to a value a height (t) higher than that of the protrusion E on the advance angle side. This constitution increases a preceding output on the advance angle side to a value higher than a subsequent output on the delay angle side.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention detects crank position, which is input information necessary for engine ignition timing control or fuel injection control, etc.
The present invention relates to a crank position detection device that outputs a signal.

[Prior Art and Problems to be Solved by the Invention] Conventionally, as a crank position detection device for an automobile engine, a device in which a protrusion is provided on a disk-shaped rotor to detect the crank position is known. The protrusions are arranged at equal or unequal pitches around the circumference of the rotor.

A rotor with such unequal pitch protrusions is, for example,
This is disclosed in Japanese Patent Application Laid-Open No. 61-23875 as an ignition device for an automobile engine.

FIG. 8 shows a conventional example of a rotor having such protrusions at uneven pitches. FIG. 8 is a block diagram of an ignition timing control device using a crank position detection device, and is a conventional rotor '101
Here, the heights of the protrusions on the circumference are all approximately the same height, and the protrusions are detected by the electromagnetic pickup 102, which is an example of a magnetic sensor, and input to the control circuit 103. The control circuit 103 converts the output from the electromagnetic pickup 102 into a crank pulse using a waveform shaping circuit, and further takes in a signal from a load sensor 104 such as a suction pipe pressure sensor, and adjusts the ignition timing based on the crank pulse. It calculates engine speed, etc. and controls ignition timing.

Here, the output voltage of the electromagnetic pickup 102 is generated by a change in magnetic flux φ when the protrusion of the rotor 102 passes through the ML pickup 102 through a predetermined clearance due to the rotation of the rotor, and this magnetic flux change dφ
A voltage (AC'\i pressure) e proportional to /di- is output from the electromagnetic pickup 102. The output of the electromagnetic pickup 102 has a signal waveform as shown in F in FIG. 7, and this signal F is input to a waveform shaping circuit to generate a slice level signal that determines the voltage level for converting the AC output of the electromagnetic pickup 102 into pulses. G and the above-mentioned signal F are ratio-scaled, and the waveform is shaped and output as a crank pulse.

Normally, with respect to the output of such an electromagnetic pickup 102, in order to prevent crank pulse output errors due to variations in the output of each electromagnetic pickup 102, the slice level is not kept constant but is changed according to the input to the waveform shaping circuit. It looks like this.

However, this slice level depends, for example, on the charging and discharging voltage of the capacitor 32 of the waveform shaping circuit as shown in FIG. The level will drop. Therefore, if noise gets into the electromagnetic pickup system, the noise will be output as crank pulses as shown in Figure 7, making it impossible to calculate the proper ignition timing and engine speed, and causing the ignition system or fuel This has caused malfunctions in the injection system, resulting in a reduction in engine output, a reduction in exhaust gas purification rate, and a worsening of fuel consumption.

[Object of the Invention] The present invention has been made in view of the two circumstances described in -1. It is an object of the present invention to provide a crank position detection device that can prevent malfunctions in control.

[Means and operations for solving the problems] The engine crank position detection device according to the present invention comprises a crank position detection unit that includes an advance side pulse detection unit (A and a retard side pulse detection member). a plurality of rotors arranged at intervals larger than the interval between the pulse detection members, and a magnetic sensor provided opposite to the pulse detection member with a predetermined clearance therebetween, the pulse detection member on the retard side; is provided with a clearance such that the output corresponding to the magnetic sensor is larger than the output corresponding to the pulse detection member on the advance side, and the pulse detection member on the advance side and the pulse detection member on the retard side are provided with a clearance. 2 from the magnetic sensor corresponding to the pulse detection member.
Of the two outputs, the output on the retard side that occurs later is larger than the output on the advance side that occurs earlier, and this becomes an output string that is continuously repeated. In the output train from the magnetic sensor, the output J is generated first in the narrow output interval, and the output generated later is larger.

[Embodiments of the invention] Hereinafter, the present invention will be described in detail with reference to the drawings.

1 to 4 show a first embodiment of the present invention, FIG. 1 is a block diagram in which the crank position detection device according to the present invention is used for ignition timing control, and FIG. 2 is a functional block diagram of ignition timing control. ,
FIG. 3 is a circuit diagram of a waveform shaping circuit, and FIG. 4 is a time foot diagram of waveforms in the circuit of FIG.

(Configuration) Reference numeral 1 in the figure indicates the engine crankshaft (not shown) as an example of a rotor that rotates in conjunction with engine rotation.
2 is an electromagnetic pickup which is an example of a magnetic sensor installed opposite to the crank rotor 1. As shown in the figure, a rectangular advance side projection E and a rectangular retardation side projection E, which are an example of a pulse detection member, are integrally formed on the circumference of the crank rotor 1 at a predetermined angle θ in the crank position detection unit 1a. Roughly speaking, the crank position detection section 1a is hung at two locations at the target position when the angle is greater than 0.Here, the protrusion on the retard side is the The height of the protrusion is higher than that of the protrusion E on the corner side.

Further, reference numeral 3 indicates a control means, and the suction pipe pressure sensor 41
Which load variable 9 and the output of the electromagnetic pickup 2 are input).

Furthermore, the control means 3 includes a central processing unit (CPU) 5, a ROM 6,
RAM 7, input/output <l10) interface 8 are provided.

The ROM 6 stores control programs and fixed data, and the RΔM 7 stores temporary parameters after processing the output signals of the electromagnetic pickup 2 and load sensor 9. .

The CPU 5 calculates the ignition time according to the programmer 11 stored in the ROM 6, and outputs an ignition signal to the base of the power transistor 10 via the I10 ink file 8.

Further, the collector of the power transistor 10 is connected to the primary side of the ignition coil 11 via a power source BV, and the emitter of the power transistor 10 is grounded. On the other hand, the secondary side of the ignition engine 11 is connected to a distributor 12, and further connected to a spark plug 1 provided in each cylinder of the engine from the distributor 1 to the distributor 12.
Connected to 3.

With the above configuration, when the ignition signal from the control means 3 is input to the power transistor 10 and the primary current of the ignition coil 11 is energized or cut off, a high voltage is generated on the secondary side of the ignition coil 11 and is passed through the detripulator 12 to a predetermined level. Spark plugs 13 of cylinders are selectively sparked.

(Functional configuration of electronic control system) The control means 3, the waveform shaping circuit 14, and the load calculation means 1
5, switch means 16, engine rotation speed calculation means 17,
Ignition angle search means 18, timer means 19, cycle calculation means 20. It is composed of an ignition time calculation means 21, which takes in output signals from the electromagnetic pickup 2, load sensor 9, etc., performs arithmetic processing, and outputs the processed signals to the ignition means 22.

Here, the output signal from the electromagnetic pickup 2 is input to the waveform shaping circuit 14, converted into a crank pulse, and output to the switch means 16.

The switch means 16 selectively switches between the signal from the protrusion E on the advance side and the signal from the protrusion on the retard side of the crank position detection section 1a, so that the timer means 19, the engine speed calculation means 17, and the I? ; They each appear in the first term calculation means 20.

In the period calculation means 20, the crank position detection unit 1
The difference between the time when the protrusion on the retard side of a is detected and the time when the next protrusion E on the advance side of the crank position detector 1a is detected is the period length of the crankshaft. Obtain angular velocity information. This angular velocity information is calculated as the engine rotation speed by the engine rotation speed calculation means 17.

On the other hand, the output signal from the load sensor 9 is input to the load calculation means 15, and engine negative values such as intake pipe pressure are calculated and input to the ignition angle search means 18.

In the ignition angle search means 18, the load calculation means 15
The basic ignition angle is determined by a map search or the like using the engine load such as the intake pipe pressure and the engine rotation speed calculated in , as parameters, and is output to the ignition time calculation means 21 .

The ignition time calculation means 21 uses the input basic ignition angle and the crank angular velocity information from the period calculation means 20 to determine the timing from when the protrusion E on the advance side indicating the reference position of the crank position detection section 1a is detected. The timer means 19 calculates the time, that is, the ignition time, and sets it in the timer means 19.The timer means 19 starts the M hour in response to the signal detected by the protrusion on the advance side, and sets the ignition time at the set ignition time. When the temperature reaches 1, an ignition signal is output to the ignition means 22.

The ignition means 22 includes the power 1 to the transistor 10 described above.
, an ignition coil 11, a destroyer 12, a spark plug 13, etc., and turns on and off the power transistor 10 in response to an ignition signal from one of the timer means, and ignites the corresponding cylinder as described above. Plug 13
sparks.

Here, as shown in FIG. 3, the waveform shaping circuit 14 is connected to the cathode of the diode 30, the anode of the diode 31, and the inverting input terminal of the comparator 36 as input terminals, and the diode 30 The anode of is grounded. The cathode of the diode 31 is connected to one terminal of a capacitor 32, and the other terminal of the capacitor 32 is grounded. Furthermore, the positive terminal of the capacitor 32 is connected to a resistor 33°3.
5 to the non-inverting input terminal of the comparator 36, while the connection end of the resistor 33 and the resistor 35 is grounded through the resistor 3/l.

Further, the comparator 36 has an output terminal and a non-inverting input q1 (child) connected through a feedback resistor 37, and is configured as a Schmitt comparator with hysteresis.

With the above configuration, the output signal (AC voltage) of the electromagnetic pickup 2 is waveform-shaped and output as a crank pulse.

(Operation) Next, the operation of the embodiment according to Nikki Kansei will be explained.

(Output from the electromagnetic pickup) When the crank rotor 1 rotates due to engine operation, the protrusion E on the advance side provided on the crank position detection part 1a
The protrusion on the retard side interrupts the magnetic field generated in the head of the electromagnetic pickup 2, and generates a voltage (alternating current voltage). This voltage is output from the electromagnetic pickup 2,
The signal is input to the waveform shaping circuit 14 as a signal shown at A in FIG.

Here, since the protrusion on the retard side of the crank position detection section 1a has a higher height than the protrusion E on the advance side, the clearance with the head of the electromagnetic pickup 2 is smaller than the clearance at the protrusion E. Above crank rotor 1
The clearance change due to rotation is too large. Therefore, the change in the magnetic flux passing through the clearance on the protrusion on the retard side is greater than the change J in the magnetic flux passing through the clearance on the protrusion E on the advance side. Therefore, as described above, since the voltage (AC voltage) generated in the electromagnetic pickup 2 is proportional to the change in magnetic flux, as shown by △ in FIG.
The voltage generated when the protrusion on the retard side passes the electromagnetic pickup 2 is larger than the voltage generated when the protrusion passes through the electromagnetic pickup 2.

(Waveform Shaping) The output signal of the N-magnetic pickup 2 is waveform-shaped by a single waveform shaping circuit 14 shown in FIG. 3, and is output as a crank pulse. This operation will be explained according to time chart 1- in FIG.

First, when the output voltage of the electromagnetic pickup 2 corresponding to the protrusion E on the advance side of the crank position detection section 1a is extremely small, the diode 31 does not conduct and the charge remaining in the capacitor 32 is discharged through the resistor 33 and 34. ing. At this time, the voltage input to the inverting input terminal of the comparator 3 is smaller than the voltage input from the capacitor 32 to the non-inverting input terminal of the comparator 36 via the resistor 33.35. Therefore, the output of the comparator 36 is at a high level.

Next, when the output voltage of the electromagnetic pickup 2 increases and the voltage at the inverting input terminal of the comparator 36 becomes larger than the voltage at the non-inverting input terminal, that is, the voltage at the cathode side of the diode 31, the output of the comparator 36 increases. At the same time, the diode 31 becomes conductive and the capacitor 32 begins to be charged.

Further, the voltage input to the non-inverting input terminal of the comparator 36 continues to rise, and finally passes the peak and falls below the charging voltage of the capacitor 32, that is, the voltage at the non-inverting input terminal of the comparator 36. The output of the comparator 36 is inverted from low level to high level again, and is shaped as a crank pulse.

Note that the comparator 36 has hysteresis due to the feedback resistor 37, and the output level of the electromagnetic pickup 2 changes relatively slowly near the inversion level of the comparator 36, even if there is output fluctuation or minute noise. Due to this influence, the output of the comparator 36 is prevented from being turned on and off unnecessarily.

Also, at this time, charging of the capacitor 32 is stopped, and discharging is started through the resistors 33 and 34.

Further, when the output voltage of the electromagnetic pickup 2 decreases, the negative component is cut off by the diode 30, and the output voltage of the electromagnetic pickup 2 is rectified. The voltage waveform at the non-inverting input terminal of comparator 36 is shown as a slice level in FIG. 4B.

Next, when the output voltage of the electromagnetic pickup 2 corresponding to the protrusion on the retard side of the crank position detection section 1a is input, the same process is repeated. Since the output voltage corresponding to the protrusion on the retard side is larger than the output voltage corresponding to the protrusion E on the advance side, the amount of charge to the capacitor 32 also increases.

Therefore, the n-angle control of the crank position detection section 1a 1
The voltage drop due to the discharge of the capacitor 32 is reduced between the output voltage corresponding to the protrusion 5- and the output voltage corresponding to the next protrusion E on the advance side, and the slice level is increased. Therefore, even if a lot of noise enters the electromagnetic pickup system, it does not reach the slice level, so that abnormal signal output from the waveform shaping circuit 14 due to noise is prevented.

In other words, for the conventional unequal pitch rotor having approximately the same protrusion height, the output generated later in the narrow part of the output interval of the electromagnetic pickup 2 is larger than the output generated earlier. Therefore, the slice level of the waveform shaping circuit 14 in the portion where the output interval is wide is increased, the noise margin is increased, and the noise resistance is significantly improved.

In this embodiment, the load sensor 9 is described as a suction pipe pressure sensor, but a throttle position sensor or an air flow meter may be used to detect the engine load. The fuel injection pulse width may also be used.

Roughly speaking, the difference t in the clearance between the protrusion E on the advance side and the protrusion on the retard side with respect to the electromagnetic pickup 2 described in - is 0.
An effect can be obtained with a thickness of 2 to 2.0 mm, and a thickness of approximately 0.5 mm is desirable.

(Second Embodiment) Next, a second embodiment of the present invention will be described. In the second embodiment, - [Members similar to those in the first embodiment described above are denoted by the same reference numerals, and explanations and illustrations thereof are omitted.

FIG. 5 shows a second embodiment of the present invention, and is a configuration diagram of a crank position detection device, in which a disc-shaped crank rotor 50 made of a magnetic material is attached to a crankshaft (not shown) of an engine. It consists of an electromagnetic pickup 2 which is an example of a magnetic sensor.

As shown in FIG. 5, the crank 1-tor 50 has a slit E2 on the advance side and a slit D2 on the retard side as an example of a pulse detection member in the crank position detection section 50a. It is placed on the circumference at an angle of 0.Furthermore,
Two of the crank position detection sections 50a are newly installed (pushed) at target positions at intervals larger than the angle θ.

Here, the notch depth of the slit 1-D2 on the retard side is also deeper than the notch depth of the slit E2 on the advance side, and the clearance with the head of the electromagnetic pickup 2 is different. Since the change in clearance accompanying the rotation of the crankshaft 50 is larger at the retard side slit D2 than at the advance side slit E2, the first
The same effects as in the example can be obtained.

At this time, the output waveform of the electromagnetic pickup 2 is the fourth
A waveform in which the sign of waveform A in the figure is reversed is output.

(Modification) FIG. 6 is a configuration diagram of a crank position detection device according to a modification of the first embodiment of the present invention. Magnetic pieces E3 and D3 are attached as pulse detection members. Exactly the same effects can be obtained in this modification as well.

[Effect of the Invention 1] As explained above, according to the present invention, the output signal train from the magnetic sensor corresponding to the pulse detection member provided in the crank position detection section of the rotor is first output at the narrow output interval. Since the output that is generated later is larger than the output that is generated, the detection level of the magnetic reno 1 no output can be increased. Therefore, the noise margin is increased in the portion where the output interval of the magnetic sensor is wide, and the noise resistance is greatly improved with a simple configuration and without any increase in cost. Therefore, even if an abnormal signal such as noise mixes into the output signal from the magnetic sensor, it will not be affected by it and will always output an appropriate rank pulse, allowing accurate ignition timing control or fuel@sword control. Excellent effects such as improved purification rate of exhaust gas and significant improvement in fuel consumption rate can be achieved.

[Brief explanation of the drawing]

1 to 4 show a first embodiment of the present invention, FIG. 1 is a block diagram in which the crank position detection device according to the present invention is used for point = 19- ignition timing control, and FIG. 2 is a configuration diagram for ignition timing control. 3 is a circuit diagram of a waveform shaping circuit, FIG. 4 is a timing chart of waveforms in the circuit of FIG. 3, and FIG. 5 shows a second embodiment of the present invention. FIG. 6 is a configuration diagram of a crank position detection device according to a modification of the first embodiment according to the present invention, FIGS. 7 to 8 show a conventional example, and FIG. 7 shows waveforms. Timetable diagram, No. 8
The figure is a configuration diagram of ignition timing control using a crank position detection device. 1.50.200... Rotor, 2... Magnetic sensor 1, 1a, 50a, 200a... Crank position detection section,
E, E2. E3... Pulse detection member on the advance side, D. D2. D3... Pulse detection section on the retard side is removed.

Claims (1)

[Scope of Claims] A rotor in which a plurality of sets of crank position detection units each including a pulse detection member on the advance side and a pulse detection member on the retard side are arranged at intervals larger than the interval between the pulse detection members. , a magnetic sensor provided opposite to the pulse detection member through a predetermined clearance, and the retard side pulse detection member has an output corresponding to the magnetic sensor, and an output corresponding to the advance side pulse detection member. A crank position detection device characterized by providing a clearance that is larger than the output corresponding to the member.