EP1607589A1 - Adjustment device for adjusting the relative rotational engle position of a camshaft in relation to a crankshaft of an internal combustion engine - Google Patents

Abstract

The adjusting device (1) has limit stops (4,5) for limiting the torsional angle between a camshaft (3) and a crankshaft. A control circuit is connected to a servo motor and configured to control the phase velocity of the torsional angle between the camshaft and the crankshaft.

Description

The invention relates to an adjusting device for the rotational angular position of the camshaft Reciprocating internal combustion engine relative to the crankshaft, with an adjusting that as Three-shaft transmission with a crankshaft-fixed drive shaft, a camshaft-fixed output shaft and an adjusting shaft is formed, which is non-rotatably connected to the rotor of a variable displacement motor is connected, wherein the adjusting stops for limiting the angle of rotation between the camshaft and the crankshaft.

An adjusting device of the type mentioned with an epicyclic gear as adjusting and an EC motor as the variable displacement motor is known in practice. The device has a camshaft gear, which via a drive chain with a rotationally fixed on the Crankshaft of the internal combustion engine arranged gear is drivingly connected. The camshaft gear is rotatably mounted on the camshaft and rotatably with the drive shaft of the variable speed connected. The output shaft of the variable speed is rotatably mounted on the camshaft and the adjusting shaft is connected to the rotor of the adjusting motor in drive connection. The stator of the adjustment motor is fixed to the engine block bolted to the reciprocating internal combustion engine. When stationary drive shaft is between the adjusting shaft and the output shaft predetermined by the adjusting Gear ratio before, the so-called stationary gear ratio. When the adjusting shaft turns, increases or decreases depending on the direction of rotation of the adjusting relative To the camshaft gear, the gear ratio between the input and the output shaft. This results in a change in the angular position of the camshaft relative to the crankshaft. The camshaft adjusting allow in comparison to a corresponding Reciprocating internal combustion engine without a camshaft adjusting device a better cylinder filling of the internal combustion engine, which saves fuel, the Reduces emissions and / or increases the output line of the internal combustion engine can be.

So that even when a possible incident occurs in the adjustment the Engine function of the internal combustion engine can be maintained, is with the crankshaft Drive shaft connected to a stop element in the use position with camshaft rotationally fixed Counter-stop elements cooperates. Due to the attacks, the Angle of rotation of the camshaft relative to the crankshaft to a meaningful in practice range of values limited. The stop and counter-stop elements are arranged such that a defined phase position results when a counter-stop element against the stop element is positioned. The adjusting motor is connected to a drive device, which in certain situations, such as after starting the internal combustion engine, the stopper element is positioned against a counter-stop element to provide phasing perform. The variable displacement motor is pulse width modulated via an output stage controlled with a predetermined pulse-pause ratio. However, this has the disadvantage the variable displacement motor varies depending on the battery voltage and the engine temperature is energized and therefore reaches different torques and speeds. When positioning the stop element against the counter-stop element, it can therefore to wear or even damage the stopper element and / or Counter stop element come.

The object of the invention is to provide an adjusting device of the type mentioned, which allows a long service life or life.

This object is achieved in that the adjusting motor is connected in a control loop, which is designed to control the phase velocity of the rotation angle.

Advantageously, the phase velocity of the rotation angle is independent thereby from the respective operating conditions of the adjusting motor, so that with the crankshaft fixed Drive shaft connected stop element always about the same speed against the connected to the camshaft fixed output shaft of the variable speed Counter stop element is positioned. In this case, the phase velocity preferably corresponds the maximum twisting speed, at which the stop certainly does not damage becomes.

In a preferred embodiment of the invention, there is a stationary gear ratio between the adjusting shaft and the output shaft when the drive shaft is stationary, wherein the adjusting device has a device for outputting a crankshaft speed signal and a device for outputting a rotational speed signal for the rotor speed ω _{Em of} the adjusting motor, these devices are connected to a signal processing device, which is designed to form a desired value signal for the rotor speed from the crankshaft speed signal, the stationary gear ratio and a target value for the phase velocity, and wherein the setpoint signal is connected to a rotor speed setpoint input of the control loop. The phase velocity ν can be calculated according to the formula ν = (ω cnk - 2 · ω em ) / i G where ω _{Cnk is} the speed of the crankshaft, ω _{Em is} the rotor speed of the variable motor rotor, and i _{g is} the stationary gear ratio. From the desired phase velocity ν _Tgt is at any time the necessary target speed ω Em Tgt = (ω cnk - i G · ν tgt ) / 2 calculated. Thus, in a reciprocating internal combustion engine with an adjusting device for the rotational angle position of the camshaft usually anyway existing sensors for measuring the crankshaft speed and the rotor speed of the adjusting motor for the control of the phase velocity can be shared.

In an advantageous embodiment of the invention, the control loop is by means of a mode selector switch switchable at least between a first and a second operating mode, wherein in the first mode, the phase velocity of the rotation angle and in the second mode, the rotor speed of the adjusting motor is controlled. It can the second mode in an internal combustion engine, wherein the crankshaft speed with a inductive sensor that measures the teeth of one on the crankshaft, for example detected on a flywheel arranged sprocket, during the starting process of the internal combustion engine be used as long as the sensor is not a tooth of the ring gear has detected and / or the measurement signal for the crankshaft speed due to the low Speed of the crankshaft is still relatively disturbed.

It is advantageous if the control loop with the help of the operating mode switch in at least one another operating mode is switchable, in which the rotor speed of the adjusting motor with at least a control parameter deviating from a control parameter of the second operating mode, is regulated. The control parameters for the regulation of the rotor speed of the variable displacement motor can thereby be adapted to the respective operating state of the adjusting motor so that the rotor speed is largely independent of the operating conditions the adjusting device and in particular largely independent of the temperature of the Transmission oil of the variable speed can be controlled.

In an expedient embodiment of the invention, the adjusting motor is an electric motor and the control loop is in at least one mode by means of the mode selector switch is switchable, in which the operating voltage and / or the operating current of the adjusting motor is regulated. The regulation can then even better to the respective operating conditions adapted to the adjusting motor.

In a preferred embodiment of the invention, the mode selector switch at least one input for one of the operating state of the reciprocating internal combustion engine dependent operating state signal, said input having means for Determining the operating state of the reciprocating internal combustion engine is connected, and wherein the mode switch is designed such that the operating mode of the control loop is set in dependence on the at least one operating state signal. It can the operating mode of the control loop, for example, depending on the operating temperature of the Combustion engine are set, assuming that the operating temperature the adjusting motor and thus the electrical resistance of the motor winding and the transmission oil temperature of the variable speed drive from the operating temperature of the internal combustion engine is dependent.

It is advantageous if the control loop has a limiting device for the torque of Servomotor has, and if the limiting device preferably on the when adjusting the adjusting shaft occurring torque values is tuned that a Limitation of the torque occurs only when positioning against a stop. By This measure is the power consumption and thus the heating of the adjusting motor limited when the adjusting shaft is positioned against the stop. In one in a motor vehicle built-in internal combustion engine is also the battery of the motor vehicle spared. The limitation of the torque can be done, for example, in the manner that the operating current and / or the operating voltage of the adjusting motor to a predetermined maximum value is (are) limited.

In an advantageous embodiment of the invention, the adjusting device has a stop detection device which provides a first input for the phase velocity signal and a second input for a torque limiting signal connected to the limiting means has, wherein the stop detection device is formed is that when limiting the torque of the adjusting motor and a simultaneous decrease in the phase velocity, positioning the camshaft against a stop is detected. The stop detection device makes it easy to Way to detect the positioning of the adjusting against the stop and with help a known, the stop associated reference position a phase adjustment perform.

Fig. 1

eine Verstellvorrichtung zum Verstellen der Drehwinkellage der Nockenwelle einer Hubkolben-Verbrennungsmaschine relativ zu deren Kurbelwelle,

Fig. 2

einen Regelkreis zur Regelung der Phasengeschwindigkeit des Verdrehwinkels zwischen der Nockenwelle und der Kurbelwelle sowie zur Regelung der Drehzahl eines elektrischen Verstellmotors der Verstellvorrichtung,

Fig. 3

eine graphische Darstellung des Verlaufs des Phasenwinkels, wobei auf der Abszisse die Zeit in Sekunden und auf der Ordinate der Phasenwinkel in Grad Kurbelwelle aufgetragen ist,

Fig. 4

eine graphische Darstellung des Verlaufs eines Sollwertsignals und eines Istwertsignals für die Drehzahl des Verstellmotors, wobei auf der Abszisse die Zeit in Sekunden und auf der Ordinate die Drehzahl in Umdrehungen pro Minute aufgetragen ist,

Fig.5

eine graphische Darstellung des Verlaufs der Drehzahl der Eingangswelle (durchgezogene Linie) und des Verlaufs der Nockenwellendrehzahl (strichlinierte Linie) eines Verstellgetriebes der Verstellvorrichtung, wobei auf der Abszisse die Zeit in Sekunden und auf der Ordinate die Drehzahl in Umdrehungen pro Minute aufgetragen ist,

Fig. 6

eine graphische Darstellung des Wicklungsstroms des Verstellmotors, wobei auf der Abszisse die Zeit in Sekunden und auf der Ordinate die Stromstärke in Ampère aufgetragen ist, und

Fig. 7

eine graphische Darstellung der Wicklungsspannung des Verstellmotors, wobei auf der Abszisse die Zeit in Sekunden und auf der Ordinate die Spannung in Volt aufgetragen ist.

An exemplary embodiment of the invention is explained in more detail below with reference to the drawing. Show it:

Fig. 1

an adjusting device for adjusting the rotational angle position of the camshaft of a reciprocating internal combustion engine relative to the crankshaft thereof,

Fig. 2

a control circuit for controlling the phase velocity of the angle of rotation between the camshaft and the crankshaft and for controlling the rotational speed of an electric adjusting motor of the adjusting device,

Fig. 3

a graph of the course of the phase angle, wherein the abscissa represents the time in seconds and the ordinate of the phase angle in degrees crankshaft,

Fig. 4

a graphical representation of the course of a setpoint signal and an actual value signal for the speed of the variable displacement motor, wherein the abscissa represents the time in seconds and the ordinate the speed in revolutions per minute,

Figure 5

a graph of the course of the rotational speed of the input shaft (solid line) and the curve of the camshaft speed (dashed line) of a variable displacement of the adjusting device, wherein the abscissa time in seconds and the ordinate the speed in revolutions per minute is plotted

Fig. 6

a graph of the winding current of the variable displacement motor, wherein the abscissa is the time in seconds and on the ordinate the current in amperes, and

Fig. 7

a graph of the winding voltage of Verstellmotors, wherein the abscissa in seconds and the ordinate in the voltage in volts is plotted.

A generally designated 1 adjusting device for the rotational angle position of the camshaft relative to the crankshaft of a reciprocating internal combustion engine not shown in detail in the drawing has an adjusting gear, as a three-shaft transmission with a crankshaft fixed Drive shaft, a camshaft fixed output shaft and an adjusting shaft formed is. The adjusting mechanism may be a planetary gear, preferably a planetary gear.

The drive shaft is rotatably connected to a camshaft gear 2, which in in itself known manner via a chain or a toothed belt with a on the crankshaft of the Internal combustion engine rotatably arranged crankshaft gear in drive connection stands. The output shaft is rotatably connected to the camshaft 3, which in Fig. 1 only partially is shown. The adjusting shaft is rotatably connected to the rotor of an adjusting motor, which is arranged in Fig. 1 at the back of the adjusting device 1. The adjusting is integrated in the hub of the camshaft gear 2.

To limit the angle of rotation between the camshaft and the crankshaft, the Adjustment device stops on, by a fixedly connected to the drive shaft stop element 4 and counter-stop elements 5 are formed. The counter-stop elements 5 are firmly connected to the camshaft 3 and act in the use position with the stop element 4 together.

As an adjustment motor, an EC motor is provided, which controls the phase velocity the angle of rotation is connected in a control circuit 6 shown schematically in Fig. 2. The control circuit 6 is designed such that during normal operation of the reciprocating internal combustion engine the phase velocity during positioning of the stop element 4 against one of the counter-stop elements 5 is set in each case such that the stop safely not damaged.

For controlling the phase velocity, the rotational speed ω _{Cnk of} the crankshaft and the rotor rotational speed ω _{Em of} the adjusting _{motor are} measured by means of sensors. From the measuring signals thus determined and the known stationary gear ratio i _{g of} the adjusting gear, a setpoint value for the rotor speed ω _{Em, Tgt of} the adjusting _{motor is} calculated with the aid of a signal processing device 7: ω Em Tgt = (ω cnk - i G · ν tgt ) / 2

The rotational speed ω _{Cnk of} the crankshaft is expediently measured with the aid of an inductive sensor which detects the passage of the teeth of a toothed ring arranged on the crankshaft, for example on a flywheel. The rotor speed ω _{Em of} the variable displacement motor is preferably measured by means of magnetic field sensors arranged on the stator of the EC motor, which detects the passage of magnetic segments which are arranged on the circumference of the permanent magnet rotor of the EC motor.

In FIG. 2 it can be seen that the signal processing _device 7 has an output 8 for the rotor speed setpoint signal ω _{Em, Tgt} , which is connected to a rotor speed setpoint _input 9 of a controller 10. The controller 10 also has an actual value input 11 connected to the magnetic field sensors of the EC motor, to which a speed measuring signal ω _{Em, Act of} the adjusting motor is applied. In the controller 10 rotor speed setpoint _signal ω _{Em, Tgt} and the speed _{measurement signal} ω _{Em, Act} a control deviation is formed. Depending on the control deviation, a signal I _{Ctrl is formed} for the winding current of the adjusting motor in such a way that the control deviation is reduced when the corresponding winding current is output to the adjusting motor. The signal I _Ctrl for the winding current is limited by means of a current-limiting device 12 to a permissible value range.

An output of the current limiting device 12 is connected to an input of an I / U converter 13, which converts the limited winding current signal into a corresponding signal deformed for an applied to the winding of the adjusting electric voltage. These is set to a permissible value range by means of a voltage limiting device 14 limited and then on an unspecified in the drawing power amplifier the winding of the adjusting motor applied.

The control loop is by means of a mode switch 15 between a first and a second mode switchable. In the first mode, the phase velocity the angle of rotation and in the second mode, the rotor speed of the adjusting motor regulated. The mode switch 15 has an input 16 for one of the operating state the reciprocating internal combustion engine dependent operating state signal. The mode selector 15 is designed such that the operating mode of the control loop in dependence is adjusted by the operating condition signal. The second mode in which the rotor speed the adjusting motor is controlled, comes during the starting phase of the internal combustion engine for use when the crankshaft speed measurement signal is not yet available or is still subject to relatively large disturbances. Once the speed of the internal combustion engine exceeds a predetermined limit, is switched to the first mode to to control the phase velocity of the twist angle.

FIGS. 3 to 7 show an actual value signal for the phase angle (FIG. 3), the signals for the rotational speeds of the three shafts of the variable speed gear (FIGS. 4 and 5), the signals for the winding current (FIG. 6) and the winding voltage (FIG. 7) using an example of a stop travel shown graphically. As can be seen in Fig. 3, the phase angle before beginning the stop travel (t≤0.7s) about 280 degrees crankshaft (Fig. 3). The rotor speed is thereby the adjusting motor and the rotational speeds of the camshaft and the drive shaft of the adjusting motor at about 2500 rpm.

During stop travel, a target phase velocity of 300 degrees crankshaft is required. From this desired phase velocity of the setpoint value for the rotor speed ω _{Em, Tgt of} the adjustment _{motor is} determined and the variable motor is energized accordingly. It can clearly be seen from the dashed line in FIG. 4 that the rotor speed of the adjusting motor increases from t = 0.7 s. As a result, the camshaft 3 no longer rotates at the speed of the camshaft gear 2 but at a lower speed, which is shown in Fig. 5 by dashed lines. This results in an increase in the actual phase angle from 280 degrees crankshaft at t = 0.7s to about 290 degrees crankshaft at t≥0.747s.

When reaching the stop, the phase angle can no longer be reduced. Therefore, the rotor speed (shown in dashed lines in Fig. 4) of the adjusting motor goes back at about 2500 rpm at t≥0.753s. Here are the current consumption and thus the torque limited by the adjusting motor.

To make this possible, the adjusting device 1 has a stop detection device 17, which has a first input for the phase velocity signal and one with the Voltage limiting device 14 connected second input for a torque limiting signal Has. The stop detection device is designed such that at a limiting of the torque or the winding voltage of the adjusting motor and a simultaneous decrease in the phase velocity positioning of the camshaft third is detected against a stop.

In Fig. 2 it can be seen that the stop detection device 17 for reducing the Current consumption of the adjusting motor during positioning of the stop element 4 against the counter-stop element 5 is connected to the current-limiting device 12.

It should also be mentioned that the control circuit 6, the mode switch 15 and the Stop detection device 17 also in the form of a computer program in a microcontroller can be implemented.

LIST OF REFERENCE NUMBERS

1

adjustment

2

camshaft gear

3

camshaft

4

stop element

5

Counter-stop element

6

loop

7

Signal processing device

8th

Output for angular velocity command signal

9

Rotor speed setpoint input

10

regulator

11

Actual value input

12

Current limiter

13

I / V converter

14

Voltage limiting device

15

Mode switch

16

entrance

17

Stop detection device

Claims (8)

Adjusting device (1) for the rotational angle position of the camshaft (3) of a reciprocating internal combustion engine relative to the crankshaft, with a variable, which is designed as a three-shaft gear with a crankshaft fixed drive shaft, a camshaft fixed output shaft and an adjusting shaft which is rotatably connected to the rotor of a variable displacement motor wherein the adjusting device comprises stops for limiting the angle of rotation between the camshaft and the crankshaft, characterized in that the adjusting motor is connected in a control circuit (6) which is designed to control the phase velocity of the angle of rotation. Adjusting device (1) according to claim 1, characterized in that there is a stationary gear ratio between the adjusting shaft and the output shaft when the drive shaft is stationary, that the adjusting device (1) comprises means for outputting a crankshaft speed signal and means for outputting a speed signal for the rotor speed ω _{Em of} the variable displacement motor comprises that these means are connected to a signal processing means (7) adapted to form a rotor speed reference signal from the crankshaft speed signal, the idle gear ratio and a phase velocity setpoint, and that the setpoint signal is connected to a rotor speed setpoint input (9) of the control loop (7). Adjusting device (1) according to claim 1 or 2, characterized in that the control circuit (6) by means of a mode selector switch (15) is switchable at least between a first and a second mode that in the first mode, the phase velocity of the rotation angle and in the second Operating mode, the rotor speed of the adjusting motor is controlled. Adjusting device (1) according to one of claims 1 to 3, characterized in that the control circuit (6) by means of the operating mode switch (15) in at least one further operating mode is switchable, in which the rotor speed of the adjusting motor with at least one of a control parameter of the second Operating mode deviating control parameters is regulated. Adjusting device (1) according to one of claims 1 to 4, characterized in that the adjusting motor is an electric motor, and that the control circuit by means of the mode selector switch (15) is switchable in at least one operating mode in which the operating voltage and / or the operating current of Adjusting motor is regulated. Adjusting device (1) according to one of claims 1 to 5, characterized in that the operating mode switch (15) has at least one input (16) for an operating state of the reciprocating internal combustion engine dependent operating state signal that this input with a device for determining the operating state of Reciprocating internal combustion engine is connected, and that the mode selector switch (15) is designed such that the operating mode of the control loop in response to the at least one operating state signal is set. Adjusting device (1) according to one of claims 1 to 6, characterized in that the control circuit (6) has a limiting device (12, 14) for the torque of the adjusting motor, and that the limiting means (12, 14) preferably in such a manner during the adjustment the adjusting shaft occurring torque values is matched, that a limitation of the torque occurs only when positioning against a stop. Adjusting device (1) according to one of claims 1 to 7, characterized in that it comprises a stop detection device (17) having a first input for the phase velocity signal and a limiting means (12, 14) connected to the second input for a torque limiting signal in that the stop detection device (17) is designed in such a way that, when limiting the torque of the adjusting motor and a simultaneous decrease in the phase velocity, positioning against a stop is detected.

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