JPH0454241B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is based on an adjustment device for setting the rotation angle of a throttle valve, which is an operating section, in a control or adjustment device for an internal combustion engine. Such a regulating device is designed in a known configuration as a reversible motor that includes a subsequent transmission and a voltage divider that detects the travel angle as a feedback variable for a follow-up amplifier, which follow-up amplifier for the motor. Provides operating voltage. Although such devices have many applications, they are relatively expensive.

In the pointer drive circuit of an indicating instrument described in Japanese Utility Model Application Publication No. 48-45671, which is a known technique, the frequency of the pulse width modulated voltage signal is selected such that the rotatable part oscillates around its adjustment point. Rather, on the contrary, the movement of the pointer is made very slow so that the pointer's response characteristics are very slow so that the pointer is accurately positioned in response to the measurement signal without over-vibration or micro-vibration. must be strongly damped and damped (this is a basic principle known in the field of technology for indicating instruments).
It is nothing more than a completely different and unrelated known technique in any respect.

On the other hand, in the case of an adjustment device for setting the rotation angle of a throttle valve, which is an operating part in a control device for an internal combustion engine, as in the present invention, the control amount or operating amount of the internal combustion engine is generally set by: This is done as a function of a control signal formed from at least one control variable. Since in internal combustion engines the operating conditions change rapidly and therefore the control signals change rapidly, such a regulating device must be able to follow changing signals as quickly as possible and, nevertheless, Must be set and adjusted accurately to the desired position. This means that in order to avoid undesirable dynamic behavior, the actuating part of the control device, the regulating device of the throttle valve, must produce only very low resistance moments.

An adjusting device which generates only a small moment of resistance when operating the throttle valve is a two-phase synchronous motor as defined in claim 1 of the present invention.

The present invention provides for such an adjustment device the requirements in internal combustion engines, i.e. the adjustment for the precise setting of the angle of the actuating throttle valve, requires only a small torque and avoids the interference of static friction. It is an object of the present invention to provide an adjustment device which satisfies the requirements of being able to precisely adjust the angle except for effects, providing a large number of variations with respect to the various control variables, and being inexpensive.

When performing pulse width control (timing control) in such a regulating device, it generally has an advantage in terms of circuit cost compared to continuous control of signal characteristics, but it also reduces the overload of the throttle valve. Vibrations and micro-vibrations, and therefore, in some cases, can lead to inaccurate position adjustments.However, according to the present invention, excessive vibrations and micro-vibrations of the throttle valve, which is the operating part, can be prevented by the indication instrument. Unlike the situation/state, it is acceptable in an internal combustion engine,
On the contrary, based on the recognition that it is desirable to minimize the moment of resistance of the throttle valve, which is the operating part, we have improved the dynamic characteristics and controllability of the throttle valve by eliminating the hindrance effect of static friction. A regulating device can be provided that performs pulse width control (timing control).

In the device according to the invention, the voltage signal (pulse signal) obtained from the control signal is on the one hand directly supplied to the first winding of the two-phase synchronous motor, and on the other hand the inversion of the voltage signal, e.g. Supplied to the other winding of the phase synchronous motor. In contrast to the prior art described above, this special connection of the two windings of a two-phase synchronous motor does not require additional switching circuit means ( transistors Q1 and Q2) are not required.

In the adjustment device for an internal combustion engine such as the present invention, it is desirable to have the throttle valve, which is the operating part, have excessive vibration or slight vibration in order to generate only a very small moment of resistance. For adjustment devices in indicating devices such as technology, excessive vibration or micro-vibration of the pointer is completely inconvenient, and differences in device configuration based on such contrasting requirements, i.e., pulse width control (timing control). The frequency of the voltage signal is selected in such a way that the rotatable part oscillates about its adjustment point, and that a complementary The present invention is quite different from the prior art in the application of voltage signals.

On the other hand, the regulating device according to the invention having the features recited in the claims provides that this regulating device can be produced in a particularly favorable manner and that a large number of control variables (exhaust gas sensor (or throttle valve position) can be applied simultaneously and in a superimposed manner. Many variants are available, and when operating the throttle valve, which is the operating part, control is carried out by means of complementary pulse signals, so that sometimes no current flows in the corresponding windings of the two-phase synchronous motor. No adjustment of the throttle valve takes place during this current pause period.
Therefore, when using the adjusting device according to the invention, the mechanical torque in the reverse direction (or in the forward direction) is small compared to the torque generated by the magnetic field, only a small moment of resistance occurs when operating the throttle valve. There are no advantages.

A variable voltage signal can be supplied to one of the windings, a first winding, used to generate both magnetic fields of variable strength, and the other winding can be supplied with a variable voltage signal depending on a controlled variable; A complementary voltage signal obtained by inversion from the voltage signal can be supplied, and the winding can be controlled by a timing-controlled voltage signal, and the impulse coefficient of this voltage signal can be varied depending on the controlled variable. It is particularly advantageous that

According to the pulse width control (timing control) of the present invention, it is possible to eliminate the effect of restraint friction that may cause errors in the rotation angle position to be set. Depending on the frequency used, the pulse width is controlled (timing controlled) so that it transiently overshoots around the desired adjustment point, then falls below in the opposite direction, and is controlled to the adjustment point while damping oscillation. The frequency of the voltage signal is selected.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows schematically an internal combustion engine 1 having an exhaust system 5 and an intake system 3, which intake system comprises:
It has a mixture generator 4 for creating and metering a fuel-air mixture for combustion within the internal combustion engine. An oxygen measuring sensor 7 of a known structure is installed in the exhaust system, and this sensor is used to detect the oxygen content in the exhaust gas and to generate a control variable, and according to this control variable, The mixture composition can be controlled. The output signal of the oxygen measuring sensor 7 is shown in an idealized form in FIG. 2A. This signal is
A known control device 8 connected after the oxygen measuring sensor is fed. This control device has, for example, an integral controller, which integrates the output signal of the oxygen measurement sensor 7, so that the output signal of the control device has a reversal point as shown in FIG. 2B. It has a saw-toothed course. These reversal points are
Determined by the control signal of the oxygen measurement (lambda) sensor. Such control devices are known which operate with oxygen measuring sensors which produce abrupt changes in the output voltage at approximately lambda 1. The output of the control device 8 is fed to a pressure divider 9 whose adjustable tap can be adjusted by a rotational movement of the throttle valve shaft 11. The throttle valve shaft 11 is used to rotate a main throttle valve 12 in the intake system 3 of the internal combustion engine. This main throttle valve is a main part of the mixture generator 4, which may be a normal carburetor, for example, and is used for controlling the mixture quantity. The therefore important parts of the intake system 3 are shown enlarged for clarity.
A constant voltage value corresponding to the position of the throttle valve 12 is added to the output signal of the control device 8 in the voltage divider 9,
The signal shown in solid line in FIG. 2C is delivered to the output of the voltage divider.

FIG. 2A shows the course of the output signal of the oxygen measuring sensor 7 in an ideal state when the oxygen measuring sensor is used for exhaust gas regulation. The oxygen measuring sensor delivers a low output signal under oxygen content in the exhaust gas (fuel-lean mixture) and a high output signal when there is no oxygen in the exhaust gas (fuel-rich mixture). mixture).

Since the embodiment shown in FIG. 1 is used to maintain a desired exhaust gas component, the position of the throttle valve is adjusted by the illustrated control device 8 to achieve the desired exhaust gas component. Since the output signal U _A of the oxygen measurement sensor changes dramatically depending on the oxygen content, it must be accurately adjusted so that the exhaust gas does not contain harmful substances and has the desired exhaust gas content. Instead, the output signal of the oxygen measurement sensor oscillates with a period determined by the engine air intake, which is schematically illustrated in FIG. 2A. Such λ control using an oxygen measurement sensor is a known technique, and its signal characteristics are also well known to those skilled in the art.

The signal curve in FIG. 2B shows the output signal of the control device 8. The control device 8 has an integral controller. The output signal of the lambda sensor 7 changes abruptly at λ=1. If the output signal of FIG. 2A has a high signal level, i.e. if the fuel mixture is too rich, the measured value of the exhaust gas composition will be λ=1.
It's off. The integral controller thereby integrates the output signal of this lambda sensor 7, and the output signal of the controller changes as shown in FIG. 2B by a straight line with a positive slope. If, by corresponding control of the throttle valve, the air/fuel mixture changes in such a way that it changes to the leaner side, the output signal of the lambda sensor 7 jumps to a lower signal level. As a result, deviations from λ=1 (with other polarities) occur again. An integral controller of control device 8 integrates this output signal, the output signal varying in the opposite direction. This is illustrated in FIG. 2B by the negative slope straight line.

The taps of the voltage divider 9 lead to a pulse width modulator 14, which, as shown in FIG. It includes a comparator that compares the tap voltage with the sawtooth voltage (e.g. 100Hz). The output terminal of the pulse width modulator has a second
As shown in Figure D, a pulse train of variable pulse width with a fixed frequency is generated in response to the signal of the oximetry sensor. This pulse train is fed on the one hand to the first winding 16 of the two-phase synchronous motor 17 . On the other hand, the output terminal of the pulse width modulator is connected to the second winding 2 of the two-phase synchronous motor 17 via an inverter 19.
Connected to 0. The other ends of both windings are grounded.

A two-phase synchronous motor is shown schematically in the figure.
The motor has a rotor 22, which is a permanent magnet and has north and south poles. The first winding 16 and the second winding 20 are wound on the stator and, when in the same direction of current flow, generate magnetic fields that are phase shifted by 90° relative to each other. This is indicated by the position of windings 16 and 20.

The rotor is connected via a shaft 23 to a bypass throttle valve 24
The bypass throttle valve is coupled to the bypass conduit 25 and is disposed within the bypass conduit 25. This bypass line bypasses the mixture generator 4 or the carburetor and the main throttle valve 12 in a known manner.

The device described above operates as follows.

In the pulse width modulator, a pulse train of variable pulse width is generated from the control signal at a constant frequency and in accordance with the input control voltage. This pulse train is on the one hand directly connected to the first winding 1 of the two-phase synchronous motor 17.
6 and inverted on the other hand the second winding 20
given to. Thereby different strengths of each other
A magnetic field rotated by 90° is created. At a duty factor of 0 or 100%, the current accordingly flows only in one winding, and at intermediate values of the duty coefficient, the current is distributed in complementary pulse trains to both windings. A resultant magnetic field is thereby generated, which can occupy a position between 90° and 0°. At this time, the rotor 22 moves to a corresponding rotational position in response to the composite magnetic field. Therefore, it is possible to realize a device that easily adjusts the shaft 23 of the throttle valve 24, which is the operating section to be adjusted, with a small resistance moment. Control by a timed pulse train provides timing control of the pulsed magnetic field and the rotor accordingly, so that the rotor can perform slight oscillatory movements depending on the pulse frequency. This acts against static friction, so that the resulting large braking moments are reduced.

It is advantageous to configure the synchronous motor in such a way that there is a magnetic field that is as uniform as possible for the movement of the rotor. For this purpose, the motor typically has, for example, a spirally extending winding groove, the pitch of the winding groove corresponding to the groove spacing.

Instead of what has been described here in the exemplary embodiments, the windings may be arranged on the rotor and the stator may be constructed as a permanent magnet. Furthermore, instead of a permanent magnet, it is likewise possible to use a winding, which is supplied with a constant direct current and thus generates a constant magnetic field.

The control voltage input to the pulse width modulator in the exemplary embodiment is generated by the control device 8 and is in the form of a sawtooth voltage. The slope of the sawtooth voltage or the time constant of the integrator that generates this voltage is
It is variable depending on the rotational speed of the internal combustion engine. For this purpose, the control device 8 is coupled to a rotational speed signal generator 27 .

Depending on the position of the throttle valve 12, the amount of fuel-air mixture supplied is determined taking into account the current rotational speed. This air-fuel mixture is usually formed, for example, in a carburetor in the air-fuel mixture generator 4, with metering of the fuel amount taking place as a function of the air amount. In order to produce exhaust gases that are as free from harmful substances as possible during operation of the internal combustion engine, the exhaust gases are fed to an oxygen measuring sensor 7.
Some air can be added to the fuel-air mixture which can be monitored for composition and pre-controlled in terms of composition via the bypass conduit 25, so that an operating mixture resulting in the desired exhaust gas composition is obtained.

Furthermore, in order to achieve as rapid a control as possible in the entire operating range of the internal combustion engine, known measures can be applied, in which the throttle valve is pre-controlled when forming the control signal fed to the pulse width modulator 14. , and the output control variable of the control device 8 is superimposed on the control signal.

However, the device can also be used for other control purposes. Instead of an air bypass, a fuel-air mixture bypass may also be used, so that the rotational speed can be controlled overall or in selected operating ranges. The metering of other active substances that take part in combustion in the combustion chamber of an internal combustion engine is also possible with the arrangement according to the invention, such as, for example, fuel, special supplementary fuel or inert gases. Instead of applying a pulsed current to the windings of a synchronous motor as described here, the coils may be supplied with a constant current of variable strength in a suitable alternative configuration, where the current strength in both coils is are complementary to each other, i.e. when the current reaches a maximum value in one winding, a minimum current flows in the other winding, and vice versa. These currents may be additionally modulated to account for further operating parameters.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a waveform diagram for explaining FIG. 1, and FIG. It is a figure provided for explanation. 1... Internal combustion engine, 3... Intake system, 4... Mixture generator, 5... Exhaust system, 7... Oxygen measurement sensor,
8...Fuel air ratio control device, 9...Adjustable resistance,
14... Pulse width modulator, 16, 20... Winding wire,
17...2-phase synchronous motor, 24...throttle valve, 25
...Bypass conduit.

Claims (1)

[Scope of Claims] 1. An adjusting device for precisely setting the rotation angle of a throttle valve in an internal combustion engine, wherein the adjusting device is provided with a two-phase synchronous motor having a fixed part and a rotatable part connected to the throttle valve. and two magnetic fields having different angular orientations and variable strengths with respect to the axis of rotation of the motor in either the fixed part or the rotatable part.
two windings are provided, the other of said fixed part or rotatable part generating a constant magnetic field, and a voltage signal pulse-width modulated by a control signal formed from at least one controlled variable is applied to said two periods. A complementary pulse width modulated voltage is applied directly to the first of the two windings 16, 20 of the synchronous motor, and at the same time to the other winding, obtained by inversion of said voltage signal. a signal is applied, the frequency of the pulse-width modulated voltage signal being selected such that said rotatable part oscillates about its adjustment point; Adjustment device to perform. 2. Adjustment device according to claim 1, wherein the rotational angular spacing of both magnetic fields of variable strength corresponds to the desired rotational range of the adjustment device. 3. Adjusting device according to claim 2, wherein the windings 16, 20 are constructed in such a way as to obtain as homogeneous a magnetic field as possible between the rotatable part and the stationary part of the synchronous motor, respectively. 4 A throttle valve 24 is connected to the rotatable part 22 of the synchronous motor 17, which throttle valve guides the at least one fuel combusted in the internal combustion engine bypassing the mixture generator 4 into a bypass conduit 25.
2. Adjusting device according to claim 1, wherein the adjusting device is arranged within the interior and is operable with force balancing. 5. The regulating device according to claim 1, wherein a pulse width modulator 14 is provided for controlling the winding, and the input control signal of this modulator is the control signal of the fuel-air ratio control device 8. . 6. Adjustment device according to claim 1, wherein the control signal is accessible via the adjustable resistor 9 and the resistance value is adjustable as a function of the second control signal. 7. Adjustment device according to claim 6, characterized in that the second control signal is the rotational position of the main throttle valve in the intake pipe of the internal combustion engine.