DE2228985A1 - Method for the numerical calculation of the speed of a motor and device for carrying out this method - Google Patents

Description

2220985

DIpI-I ... H. MITSCHERIICH ΪΑΚ *

Dipl.-Ing. K. GUNSCHMANN τθΜρπ: ιοβπ) 2? Ί6 Dr. rer. not. W. KORBER

PATENTANWÄLTE / if- £ _f -

DIRECTED BY NATIONALE DES USINES RENAULT

8/10, avenue Emile Zola

Billancourt (Hauts de Seine) France

and

AUTOMOBILE PEUGEOT

75, avenue de la Grande Army

Paris, France

Patent application

Method for numerical calculation of the speed
a motor and device for implementation
this procedure

The invention relates to a method for electronic measurement of the speed of an internal combustion engine and a
Apparatus for carrying out this process. The invention is particularly applicable to a method in which this measurement takes place in numerical form and which can be applied as such by a simple code conversion in an automatic system or by analog-digital conversion, which as a variable into a

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Computing system is entered that the operating conditions of the engine controls.

The ignition of the engine is one of the most important factors affecting the operating conditions and the timing of ignition must be determined with ever increasing precision. The same applies to injection engines the injection timing. These factors make one high precision in the measurement of the speed of the motor and thus the setting of the Liiimer control is necessary. at In the known methods, the interruptions in the electrical control of the ignition coil occur with an inadequate Sensitivity and moreover means the inclusion of this Impulses a considerable disturbance of the ignition conditions of the Motors, besides, these procedures are applied to positive-ignition engines limited.

Measuring the speed of the engine with precision and with extremely small delays is the task of the invention Procedure.

The inventive method differs in essentially through the absorption of electrical impulses emitted by the rotating organs of the engine and can be recorded by a combination of pickups that emit asynchronous pulse numbers, which per rotation of the motor are different for each transducer, which transducers correspond to the same number of rows of display elements, those by teeth at equal intervals and / or over the circumference of the corresponding revolving organ unevenly distributed approaches are formed, where if η is the number of display elements in the largest row is which is the highest pulse frequency per motor revolution for the corresponding transducer, and q is the

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is the total number of transducers, one obtains a sensitivity the angle measurement of -, and where the pulse frequencies obtained are brought into shape, then with a fixed reference frequency can be compared and counted.

According to a further feature of the invention, the device for measuring the speed of a motor differs essentially according to the method described above in that a pulse generator of high frequency is provided which is controlled by an oscillating circuit is, and a gear that is driven by the motor and coupled to the inductance of the resonant circuit so that the pulse generator is synchronous with the passage the teeth are alternately excited and blocked in front of the inductance mentioned.

At a reference frequency, vas] before with reference to the pulse frequency the pickup is high, the number of reference pulses with respect to a given pickup pulse count becomes counted. In this way there is a speed information which is inversely related to the speed of the engine is proportional.

It can also be the time of passage of a given number of pulses can be measured according to the aforementioned reference method. Information is also received here, which is inversely proportional to the speed.

With a reference frequency that is low in relation to the pulse frequency the number of pulses during fixed times is measured and the information obtained in this way is proportional to the speed of the motor.

The precision of the measurements depends on the difference between

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ignore the pulse frequency and the reference frequency. the The precision of the angle measurement is proportional to the number of transducers and the maximum number of pulses per motor revolution one of the transducers.

After counting the pulses, the result is treated by a divider, for example a dynamic shift register can be what the achievement of the appropriate format of the binary value at the output of the computing cell of the reciprocal of the angular velocity of the motor allows · This result is then either in a converter with analog-digital conversion for use as a calculation variable or with code conversion for direct application treated on an automatic control.

The electronic elements used to carry out the method, such as counters and shift registers as well as the monostable flip-flops and the analog-to-digital converters are currently commercially available in the form of integrated circuits obtainable, which allow an economical implementation of the process according to the invention. Solutions with separate components would generally be more cumbersome.

For a better understanding of the invention, it will be explained below with reference to an application of the method and a Embodiment of the device for carrying out the method, for example 'in connection with the enclosed Drawings described in more detail and show:

1 shows a schematic representation of an inventive device Device for an internal combustion engine;

Fig. 2 shows a sequence diagram of the operation in the case of a hyper-

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Bolic coding of the speed according to a high reference frequency;

FIG. 3 is a sequence chart showing the operation in the case of a direct numeric coding when the reference frequency is low;

4 generated in the circuits according to the invention Signals;

5 further generated in the circuits according to the invention Signals;

6 shows a circuit according to the invention for generating a Square wave signal according to FIG. 4;

7 shows an HF pulse generator according to the invention;

Fig, 8 a circuit according to the invention, which a Clock pulse generated which is synchronous with the output signal of the generator of FIG. 7;

9 shows a circuit according to the invention which has a pulsating Signal generated which is derived from the output signal of the circuit of FIG. 8 and its ■ Frequency allows the engine speed to be determined;

FIGS. 10 and 11 show signals which provide a better understanding of the Enable the operation of the circuit according to FIG.

In Fig. 1, a motor 1 is shown with a diagrammatic representation, one of which is advantageously as a pulsing rotating

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Organ of the starter ring gear 2a used is adjacent which proximity sensors 3 and 4 are arranged · These Pickups are preferably of the electromagnetic or electrostatic type,

The transducer 3 is arranged directly above the teeth of the ring gear 2a, whereby as many pulses each Rotation are guaranteed than the ring gear has teeth. The transducers 4 for angle measurement are by approaches 5 activated, which are mounted on the flywheel 2b of the engine 1 and ensure the angle measurement of the engine. These approaches are angularly offset with respect to the teeth of the starter ring gear 2a in order to provide any pulse synchronism of the various transducers. The proximity sensors can either be attached to the lower housing of the Engine blocks or clutch housing to be attached to their proper location with respect to the teeth of the starter ring gear and to allow the approaches 5 for angle measurement.

The number of proximity sensors of type 3 and type M- is not limited. In fact, when η is the number of teeth of the ring gear 2a, it becomes the real angle measurement

q CA

determined to the nearest degree by a Type 5 approach.

If there are two type 5 transducers which are offset by (p + _) teeth, the angle measurement that can be obtained from a type 5 approach is accurate to 360 degrees, and generally occurs when q transducers

are provided that are offset by (p + -) teeth, the Angle measurement obtained from a Type 5 approach

O CA

accurate to -—- degrees. Interest in such an arrangement is obvious if you look very precisely at the ignition timing or the optimal amount of gasoline that is most favorable Time to be injected tries to calculate.

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The pulses obtained in this way are shaped by a monostable flip-flop 6. It can also a Schmitt trigger circuit can be used. The shaped pulses are then referenced processed on the pulses of a clock in a counter 8, then by a divider 9, for example through a dynamic shift register, and finally in a converter 10, which does the analog-to-digital conversion or a code conversion to use the information "speed" obtained in this way is guaranteed.

Depending on the frequency of the clock generator 7, this speed measurement can be done in several different ways:

a) the cycle time of the interval is measured, which separates two or more teeth of the ring gear 2a. A clock generator 7 of high frequency (of a frequency which is high compared to that of the passing of the teeth of the ring gear) and the number of pulses to count during the passage of two or more consecutive teeth of the ring gear 2a. Through this information is obtained which is inversely proportional to the speed of rotation of the ring gear.

b) it becomes the throughput time of two or more batches of type 5 according to the method identified above measured. Information is then obtained which is inversely proportional to the speed of rotation of the flywheel 2b is·

c) it is also possible to measure the number of teeth of the ring gear 2a which are in front of a type 3 sensor fixed times. It is enough in this Trap, a clock of low frequency (very low with respect to that of the passing of the teeth of the ring gear 2 (in order to obtain adequate precision,

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This results in a speed of rotation of the Ring gear 2a proportional information.

The following diagram in FIG. 2 shows the mode of operation of the device for numerical hyperbolic coding of the Speed corresponding to the method according to a) and b).

The Zeife 6 -. > 8 shows the profile of the flip-flop 6

emitted and the counter 8 feeding pulses. Line 7 ^ 8 shows the counting periods for the clock pulses of high frequency. The line RAZ 8 represents the zeroing pulses of the counter 8, which by the leading edge the pulses emitted by the monostable flip-flop 6 are triggered. Finally, line H shows the pulses of the time axis of the clock 7.

As can be seen, the zeroing of the counter is a very short process compared to the duration of the pulses 15. The error brought in by the lack of counting during the zero setting is therefore insignificant and can be disregarded with full justification: it is sufficient that the frequency F of the clock 7 is ^{very high compared to that F 1 of} the signals 15. If F = KF ¹ , the zero setting takes place during a pulse of the clock generator 7, so that the relative error committed is therefore equal to 1 / K of the height of the counter

In the same way, the following diagram in FIG. 3, which corresponds to the measuring method according to c), shows the output of the shaping flip-flop 6 can be obtained in the row 6> 8 shown. Line 7 ^ shows the counting pulses of the clock 7, this time a clock of low frequency, which gives very wide pulse profiles 11.

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The line RAZ 8 shows the zero setting signals of the counter 8, which are caused by the trailing edge of the pulses 11 of the clock 7 are triggered. Finally, line 12 shows the concatenation of the pulse counting phases 13 and the zeroing phases 14 of the counter 8.

According to the invention, a synchronizing pulse generator or clock generator of stabilized high frequency provides a Pulse train that is 100% modulated by a gear wheel that is driven by the shaft of motor 1 and that for example the ring gear 2afles starter (Fig.l) can. This clock generator blocks itself when a tooth of the mentioned wheel is in front of one to switch the clock generator belonging coil moves past.

4 shows, as a function of time, the signal A obtained in this way, which comprises pulse trains T., T ₂ , which are separated from one another by rectilinear parts A ₁ , A ₂ . The square-wave signal B represents a signal derived from signal A by a suitable circuit, which replaces the pulse trains T ₁ , T ₂ ... with individual pulses I., I ₂ ... The lower pulse tops of signals A and B preferably correspond to the potential 0, ie the ground potential * For example, the clock generator can have a frequency of 1 MHz and the ring gear of the starter can have 139 teeth. At an engine speed of 6000 rpm, for example, the number of pulses of the pulse train T _{1 is} about 20 and the period of the pulse train B is about 72 microseconds, which corresponds to a frequency of 13,900 Hz.

In FIG. 5, in which the arrow pointing downwards on the left-hand side denotes the release threshold, the superimposition of the pulse trains T ₁ and I ₁ of FIG. 4 is shown on an enlarged scale. To ensure good precision

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To measure the speed of the motor, it is necessary that the pulse I _{1 is} triggered when the first clock pulse arrives, has steep leading edges and falls back immediately after,; at the end of the cycle of the last clock pulse.

In FIG. 6, which shows a circuit according to the invention which corresponds to the conditions mentioned, it can be seen that the signal A arrives via the line 16. It is generated by a transducer described in more detail below. The signal is then amplified by a circuit with the resistors R. to Rj-, the capacitor C. and the transistor Tr. And then stabilized to a constant level with the aid of the Zener diode D. The signal amplified and stabilized in this way is fed to terminal U of a monostable flip-flop with automatic reverse triggering. Functionally, this flip-flop is triggered back by any signal with an amplitude that is greater than a certain value. Under the condition that such successive signals are generated at time intervals less than a threshold value, the output level of the flip-flop is constant. One example is the T 118 flip-flop, which is marketed by the American company SGS F Fairchild. For example, this threshold can be about 1.1 microseconds, while the clock pulses, as mentioned, have a period of one microsecond, which corresponds to the diagram of FIG. The signal B is therefore obtained at the output 8 on the line 17. This circuit is fed by the vehicle battery, which has a nominal voltage of 12 volts, for example, and the positive pole of which is connected to the terminal I ^ of the flip-flop via a resistor R-, the terminal 7 of which is connected to ground.

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stabilized, which is connected in parallel to a capacitor C _2.

7 shows an oscillator that can serve as a clock generator according to the invention. It is a quartz-stabilized oscillator.It has a quartz Q, a field-effect transistor Tc, an LC-type resonant circuit with a self-induction coil Lo ₉ which is arranged near the starter ring gear and a capacitor Co, a variable capacitor Cv, resistors R ₇ , R_ and a filter capacitor Cg * The output of the switches is received on line 19. The supply voltage Vo is supplied by the vehicle battery. The quartz Q is connected between the base Bc of the transistor Tc and the source Sc, which is connected to ground, while the resonant circuit 18 is supplemented by a feedback capacitor C ¹ which is connected to the drain Dc of the transistor Tc. For example, with a crystal of 1 MHz for Co = H7O picofarad, L β 90 microhenry, Vo = 5 volts, an alternating signal with a frequency of 1 MHz is obtained, the amplitude of which is 5 volts from maximum value to maximum value. The capacitor Cv enables this frequency to be changed by - SO Hz »

Such an oscillator has the advantage that it is a very has little frequency fluctuating depending on the temperature

FIG. 8 shows a clock generator which is a circuit which is derived from the circuit according to FIG. 7 and which enables the generation of a pulse train of the same frequency, but of rectangular shape and positive, the lower level being the potential of the Ground is · In addition to the switching elements of FIG. 7, the circuit has a Schmitt trigger circuit Bs, fixed resistors Rg, R ₁₁ , ^R t2 * ^R 13 * ^e * a ^variable resistor

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Capacitors Cg, Cg and C ~, a transistor amplifier TTo · The output signal H is transmitted to conductor 20 « The flip-flop Bs receives the output signal of the field effect transistor Tc at its input 13 and delivers it its output signal at its terminal 8. The two terminals m and 7 are connected to the positive supply voltage Vo or connected to the ground. The output voltage on the conductor 20 fluctuates between 0 volts and + Vo volts,

FIG. 9 shows a circuit which enables the generation of a pulsating signal S which is formed by a square pulse which is synchronous with a clock pulse after each trailing edge of the signal B of FIG. 4, which is supplied by the circuit of FIG will. The circuit according to FIG. 9 is a combination of the circuit according to FIG. 8 and a circuit which is controlled by the clock and is described below. The pulsating signal applied to the conductor 20 is fed to a counter Cm of a known type which produces three output signals A ", B ₂ , C _{1 is} generated on three separate outputs and has a counter input CP and a zero position input RAZ. The signal B originating from the output line 17 in FIG. 3 is fed to the input RAZ. This circuit also has two circuits P ₁ and P ₂ of the NO-AND type and four non-circuits K ₁ , K ₂ , K ₃ , K ₁₊ . The clock signal H is the counter input CP. supplied via the circuits P ₁ and K _2. The circuit P ₁ receives the signal H at its first input and the signal C ₁ at its second input. The signals A ₂ , B ₂ and H are fed to the circuit P ₂ , "the output of which is connected to the input of the circuit K ₁₊ , which supplies the signal S sought at its output.

The operation of the circuit can be better understood in connection with FIGS. The clock signal is at

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H (Fig. 10). The counter Cm has three stages for division by 2 and has a conventional circuit (not shown) and internally generates the signals A ₁ , B ₁ and C ₁ of FIG. 10, the frequencies of which are half, a quarter and 1/8 of the repetition frequency of the signal H. The signal that is fed to the input Cp is a signal Cp, which is the same in the logic of Boole:

C ₁ + H ... so that
Cp = "C7 + H

The signals A ₂ and B ₂ are synchronous signals to the signals A ₁ and B ₁ , but are conditioned by the signals B and C ₁ and have the following logical values:

A ₂ = A ₁ + B +
and B ₂ = B ₁ + "B +

In other words, the counter Cm counts the pulses Cp to two and two, but it is also by the signal B conditioned.

The output signal S is as follows:

S = H + A ₂ "+ I ₂

This signal, which is shown in FIG. 11, corresponds well to the definition given above, since it appears only once before the upper level or level "1" of the signal C ₁ .

This signal S enables the measurement of the instantaneous

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speed of the motor, for example by counting the number of pulses of this signal that are generated in a given time, or by determining the instantaneous frequency ^ of these impulses.

In practice, the non-circuit K ^ can be a transistor operating between two voltage levels, for example between 0 volts (i.e. ground) and 5 volts.

Claims;

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Claims (1)

Patent claims 1 »Method for the numerical calculation of the speed of a motor using the electrical impulses generated by the rotating parts of the motor, characterized by a combination of sensors that emit asynchronous numbers of pulses that are different for each motor revolution, which sensors have the same number of rows of display elements which are formed by teeth at regular intervals and / or approaches, the latter being unevenly distributed over the circumference of the respective revolving organ, and in such a way that, if η is the number of display elements in the largest row, which has the highest pulse frequency per revolution for the corresponding transducer and q is the total number of transducers, one is a Q C QO Sensitivity of the angle measurement from —_ ■ - receives that received pulse frequencies are brought into shape, counted and then compared with a fixed reference frequency, then divided and for use either in analog form or directly by appropriate coding in a automatic control device can be implemented " 2 «Method according to claim 1, characterized in that the highest pulse frequency per revolution is obtained by the teeth of the starter ring gear of the engine is used as the largest set of display elements. 209853/0779 222898S 3, method according to claims 1 and 2, characterized in that the pulses for angle measurement by display attachments which are placed on the flywheel of the engine and which refer to the teeth of the starter ring gear are staggered * H. The method according to claims 1, 2 and 3, characterized in that that the fixed reference frequency is obtained by a clock of high frequency, the number of pulses with respect to a given number of pulses the transducer is high « 5 «method according to claims 1, 2, 3 and f, thereby ge * indicates that the lead time is a given Number of pulses as a function of reference pulses is measured. 6, method according to claims 2 or 3, characterized in, that when the fixed reference frequency is low with respect to the pulse frequency, the number of Pulses are measured during fixed times depending on the reference frequency « 7. Device for measuring the instantaneous speed of a motor vehicle engine, gekennaeichnet by a pulse generator of high frequency, which is caused by an oscillating 209853/0779 circle and a gear (2a) is controlled, which is driven by the motor (1) and with the inductance of the oscillating circuit is coupled in such a way that the pulse generator alternates and synchronizes with the passage of the mentioned teeth on the inductance is excited and blocked * Device according to Claim 7, characterized in that the pulse generator has a field effect transistor (T), the source (S) of which has a ground connection via a resistor (Rg), and also a quartz (Q) which is connected between the base (B _c ) and the ground and an oscillating circuit (18) connected between a continuous voltage (V) supplied by the vehicle battery and the drain (D _Q ) of the transistor. 9, device according to claim 7 with a circuit for Conversion of the output signal of the mentioned generator into a square-wave signal which forms the envelope of the output signal, characterized in that this circuit has a special monostable flip-flop (B) connected to the output of the generator, which maintains its initial level as long as the period of the pulses supplied to it is less than has a certain time value. 10, device according to claims 7 and 9, characterized by a pulse counter (Cm) with two stages sue »division 209853/0779 by . iei and a counter input (CP) as well as with a zero position input (RAZ) to which the output signal (B) of the circuit for generating the square-wave signal is supplied, with two output signals of the counter, which are conditioned by the square-wave signal, an AND circuit (P ") simultaneously with a pulsating clock signal (H) are supplied, which is synchronous with the output signal of the high-frequency generator is which AND circuit supplies the measurement signal (S) at its output. 11, device according to claims 7 and 10, characterized in that the counter input (CP) is connected to the output of an AND circuit (Pj), the input signals of which are followed by the clock signal (H) and a third output signal (C ₁ ) of the counter are the inversion. The patent attorney 209853/0779 Lee side