WO2006122665A1 - Apparatus comprising an electric camshaft adjuster, a control unit, and a central control device - Google Patents

Abstract

The invention relates to a topology for generating an actuating signal for an electrically actuated camshaft adjuster. According to the invention, an actuating signal (28) is regulated in a regulation unit (25) which is disposed in a central control device (19a), particularly the engine control device. The actuating signal (28) is transmitted to an actuating unit (10a) allocated to the camshaft adjuster via an adequate interface or a bus system and is converted into an adequate electric signal by means of the commutation logic (30) and the power electronics (31) in order to trigger the servomotor (32). Compared to prior art, the regulation unit (25) is thus transferred from the control unit (10a) to the central control device (19a). The invention is used for camshaft adjusters of internal combustion engines of motor vehicles.

Description

 Name of the invention

Device with an electric camshaft adjuster, a control unit and a central control unit

description

Field of the invention

The invention relates to a device for adjusting a rotational angle of a camshaft relative to a crankshaft of an internal combustion engine with an electric camshaft adjuster, a control unit and a central control device according to the preamble of patent claim 1.

Background of the invention

Known camshaft adjusters are usually associated with a control unit which is arranged in the housing of the camshaft adjuster or screwed to it. In the control unit, a control signal is generated via a suitable control, which correlates with a desired angular position of the camshaft adjuster.

Document DE 102 29 029 A1 shows a hydraulic camshaft adjuster, in which a control signal is generated in a control unit, in accordance with which hydraulic chambers of the camshaft adjuster are subjected to the hydraulic medium. The control unit is in signal communication with a central engine control unit, wherein the control unit can transmit to the central engine control unit a signal which influences the specification of the idle speed and is adapted to raise the idle speed from a predetermined target speed to an intermediate value.

Further prior art is known from the publications DE 101 01 678 A1 and DE 103 15 317 A1. Object of the invention

The invention has for its object to provide a device with a camshaft adjuster, in which a control of the camshaft adjuster using a camshaft adjuster associated with the control unit with special consideration

the existing signal connections, - the construction cost for the control unit, the use of existing components and / or the space requirements

he follows.

Summary of the invention

According to the invention the object is solved by the features of independent claim 1.

The ideal requirement for a camshaft adjuster is exact compliance with the setpoint course. In reality, there are deviations between a desired angular course and an actual angular course. To minimize this deviation, regulations are used that are based on a highly dynamic detection of position information. In addition to the signals of the crankshaft sensor and the signals of the camshaft or the sensors and the position information is evaluated, which is needed for electronic commutation of a brushless servo motor. This can be done sensor-based as well as sensorless by a software. For this purpose, one or more arithmetic processors are necessary, which are costly.

The present invention is based on the recognition that motor vehicles, on the one hand, have a high-performance motor control unit on the one hand anyway. seen and on the other hand additionally memory elements, logic elements, processors u. Ä. In the range of the camshaft adjuster associated control unit are present, which serve to carry out the control of the camshaft adjuster.

Based on this knowledge, the invention proposes to shift sub-functions of the control unit from this to the central control unit. This results in a multifunctional use of the central control unit, which can be used in addition to the use of the camshaft adjuster, for example, a motor control and / or a transmission control.

According to the invention, the central control unit is configured in such a way that an actuating signal can be determined in the control unit by evaluating signals and operating variables present by the central control unit. The actuating signal correlates with a desired position of the camshaft adjuster. In this context, the term "desired position" means any possible generalized coordinate of the camshaft adjuster or a drive element thereof, for example a rotational angle, a rotational speed, a rotational direction, an actuation of an actuating element or the like. This means that the components required for determining the actuating signal and / or control or regulation algorithms can be omitted in the control unit associated with the camshaft adjuster, whereby the construction costs and the costs for the control unit and thus the camshaft adjuster decrease. Accordingly, it is sufficient for the control unit to be suitable for converting the actuating signal into an adjusting movement of the camshaft adjuster, whereby, of course, additional functions may also be taken into account in the control unit. For example, the control unit has only one supply unit, a control / commutation logic and power electronics. Furthermore, a sensor device with suitable supply, in particular Hall sensors, can be taken into account in the control unit.

Furthermore, the invention makes use of the fact that a large number of signals, In particular, operating parameters of the internal combustion engine, environmental parameters, power control signals of the driver and / or monitoring signals, anyway in the range of the central control unit so that they do not need to be unnecessarily fed to the control unit of the camshaft adjuster. This can u. U. lines and connections that are prone to failure and installation consuming, can be saved. In the event that there are special signals required for determining the actuating signal in the control unit, for example the measuring signals from sensors for the adjusting movement of the camshaft adjuster, these can be supplied by the control unit of the camshaft adjuster to the central control unit.

The inventive design results in u. U. a cost shift from the control unit away to the central control unit. Furthermore, as a result of the more favorable infrastructure in the central control unit, a cost reduction can result. Furthermore, according to the invention, the documentability of possible system errors can be improved since signals correlating with the system errors can be stored in the central control unit with all relevant error data. In addition, the efficiency of the device can be increased if the power electronics are arranged in the immediate vicinity of the electric servomotor. This is due to a reduction of electromagnetic interference (improved electromagnetic compatibility) and in a loss of power losses at the leads and connectors between power electronics and electric servomotor. Since cable lines and plug connections according to the invention can be dispensed with and u. U. the size of a housing of the camshaft adjuster and / or the control unit can be reduced, according to the invention also results in a reduced weight. Another advantage of the embodiment of the invention is to call that u. U. temperature-sensitive electrical components for controlling the Stellellsig- signal from the internal combustion engine, which generates high temperatures, are shifted away. Also, the number of interference-prone connectors can be reduced, which is given a further reduction of error sources. According to a preferred embodiment of the device according to the invention the camshaft adjuster is designed as an electric camshaft adjuster, so that the electrical control signal does not have to be converted into a hydraulic manipulated variable, but the electrical control signal can be converted into electrical signals without a change of the "medium", with which electric camshaft adjuster is electrically applied. For this purpose, the control unit on controls that are configured so that the electrical signals cause an adjustment movement of the camshaft adjuster in the desired position of the camshaft adjuster. Between the central control unit and the control unit, a signal connection is provided, via which at least the control signal is transmitted from the central control unit to the control unit - the supplementary transmission of further signals in both directions is also possible. After a u. U. remote installation of the central controller on the one hand and the camshaft adjuster on the other hand (and the associated control unit) according to the invention, only a signal connection between the controller and the control unit must be made, for this purpose, a separate, additional signal connection can be used or anyway in the vehicle provided signal connection such as a bus system, which thus can also be used multifunctional.

According to one embodiment of the invention, the central control unit is connected to the control unit via a plurality of separate lines, are transmitted via the position and / or speed information from multiple sensors of a camshaft adjuster. Such a configuration is used, for example, when Hall sensors are used to acquire the position and / or speed information. For multi-phase brushless electric motors, where the number of Hall sensors correlates with the number of phases of the electric motor, the signal of each Hall sensor is transmitted via a separate line. For example, four lines are thus required for a four-phase motor. The transmitted position or rotational speed information may be, in particular, those of one, two or, for V-type engines, four camshaft adjuster (s). Since actuators in conjunction with camshaft adjusters have speeds of up to 10,000 revolutions per minute and, for example, per revolution of a camshaft adjuster 42 Sensorbzw. Sensorless signals must be processed (in a brushless AC motor with seven pole pairs), offers a line connection with separate lines for each Hall sensor information.

For an alternative embodiment of the invention takes place to reduce the system overhead a summary of multiple lines. A variant of the invention is that the signals of several sensors of a camshaft adjuster are combined and sent via a line. This is u. U. possible because switching points of the individual sensors offset from each other. However, this may mean that a directional information of the signal is lost. For this reason, a direction signal is determined in the control unit on the basis of the individual sensors of the camshaft adjuster which, in addition to the combined sensor signals sent via a line, is transmitted to the central control unit via a second, separate line. Thus, regardless of the number of phases of the engine, only two lines are required between the phaser or control unit and the central control unit-for a three-phase motor this means a reduction in the number of lines from three lines for the sensors assigned to each phase to two Lines for the combined signal and the direction signal.

A further simplification can be brought about according to the invention in that rotational angle, rotational speed and rotational direction information of two or more camshaft adjusters are placed together on the aforementioned two lines. For this purpose, for example, be carried out a coding of the signals in the control unit, for which the known methods, such as an amplitude modulation, can be used. According to a development of the invention, signals are exchanged between the central control unit and the control unit via a bus system. Such bus systems are characterized by a sufficiently large transmission bandwidth and low latency fluctuations. The requirements for the dynamics of the control loop determine the appropriate bus systems. For low requirements, soft real-time bus systems, such as a CAN bus system, which can be used exclusively or alternatively as a "shared medium", suffice. For highly dynamic control processes, hard real-time bus systems are to be preferred. As X-by-Wire technologies continue to evolve, they will increasingly be used in automobiles. Examples of applicable bus systems are TTCAN, FlexRay and TTP / C. These bus systems are also characterized by a deterministic behavior. Preferably, the associated bus controller is integrated directly in the microprocessor or in the application-specific integrated circuit of the control unit of the camshaft adjuster. Mixed forms to the described forms are also conceivable.

According to a further proposal of the invention, the control signal generated in the central control unit includes a position and / or speed signal and a direction of rotation signal, which are transmitted via separate lines. The position and / or speed signal can be transmitted, for example pulse-width modulated and is particularly proportional to the idle speed of the electric motor.

However, it is also possible that the position and / or speed signal and the direction of rotation signal are transmitted via a common line. For this purpose, the direction of rotation signal can be encoded to the speed signal. For example, such a coding takes place via the duty cycle. Preferably, a duty cycle between 0% and 50% corresponds to a clockwise rotation while a duty cycle between 51% and 100% corresponds to a counterclockwise rotation. The duty cycle 0% and 100% corresponds to the maximum engine speed. According to the invention, the diagnosis can be improved if a signal exchange takes place between the central control unit and the control unit for diagnostic functionalities via a line or a bus system.

Instead of using Hall sensors or other sensorless detections of states of motion of the camshaft adjuster, it is also possible to detect position information of the rotor of an electric motor used in the camshaft adjuster via a separate sensor system. This is, for example, an optical sensor with a slotted disk or an encoder. The advantage of such embodiments is that u. U. a line sufficient for the transmission of the position signal to the central control unit.

Advantageous developments emerge from the subclaims, the description and the drawings. Further features of the drawing, in particular the illustrated geometries of the components, the relative dimensions of several illustrated dimensions of the same or different components, the relative arrangement of the components to each other and their operative connections with each other, refer. The combination of features of different embodiments shown in different figures, features of different claims different from the selected relationships and features of the claims with single or multiple features of the description is also possible and is hereby stimulated.

Brief description of the drawings

Preferred embodiments of the device according to the invention will be explained in more detail with reference to the drawing. In the drawing shows:

Figure 1 shows a device with a control unit in which determines the control signals for several camshaft adjuster by a scheme becomes;

Figure 2 shows an inventive device in which a control of the control signal for at least one camshaft adjuster via a central control unit takes place; and

Figure 3 shows another device according to the invention, in which the signal connection between a control unit and a central control unit via a bus system.

Detailed description of the invention

In the following figures with different embodiments of the invention, components with a corresponding function or corresponding structure are provided with the same reference character, wherein components according to the embodiment shown in Figure 2 with the letter a and components according to the embodiment shown in Figure 3 with the letter b Marked are.

The figures show a topology for the electrical control of at least one camshaft adjuster 1, 2, with which the angular relationship between a camshaft 3, 4 and a crankshaft 5 with a flywheel 6 is variable. As camshaft adjuster 1, 2 camshaft adjuster of any type can be used. In the following, reference will be made to a camshaft adjuster for simplicity, in which the adjusting unit of the camshaft adjuster is designed as a multi-phase brushless DC motor. The camshaft adjuster 1, 2 is connected via lines 7, 8, 9 in signal communication with a control unit 10. The lines 7, 8, 9 can serve:

a) to supply the camshaft adjuster 1, 2 with different phases of the electrical power, b) to transmit sensor signals from a sensor of the camshaft adjuster, in particular a Hall sensor, to the control unit 10 and / or

c) provide a basic power supply for a sensor of the camshaft adjuster 1, 2 available.

The control unit 10 is further in signal communication with a bus system 11 (CAN) and terminals 12-14 (designation in the vehicle: "terminal 15", "terminal 30", "terminal 31"). The camshafts 3, 4 each have a transmitter wheel 15, which cooperates with a sensor 16, and a Mehrfingergeberrad 17, which cooperates with a sensor 18. The measuring signal of the sensor 15 is fed to a central or further control unit 19, which takes over, for example, control functions for the internal combustion engine and / or the vehicle transmission and possibly includes further functions. In the region of a ring gear of the flywheel 6, a sensor 20 detects a crankshaft signal. The signals of the sensors 16, 20 may be looped through the central control unit 19 to the control unit 10. If all required signals and variables are present in the control unit 10, a determination of the actuating signal for the camshaft adjusters 1, 2 in the area of the control unit 10 is carried out for this embodiment.

A different topology is shown in FIG. The central control unit 19a signals 21, 22, in particular a sensor 20 of a crankshaft and / or a camshaft associated sensor 16, 18, and / or signals for detecting further operating variables of the internal combustion engine, environmental parameters and / or a power requirement of the driver fed. Other signals may be received and transmitted by the central controller 19a via the bus system 11a. In the central control unit 19a further a map 23 is stored. From the map 23, at least one control variable 24 can be determined from available signals 21, 22 and other variables, which may be, for example, a desired angle, an angular change, an angular velocity, a Limit value, a control parameter or the like.

Furthermore, in the central control unit 19a, a control unit 25 is provided, which on the one hand, the control variable 24 and on the other hand, a position information 26 of a camshaft adjuster 1, 2 is supplied. The position information is in particular a rotation angle, an angular velocity and / or a direction of rotation. The position information may also include encoded data. In the control unit 25, a control algorithm 27 is stored, which essentially corresponds to the known control algorithms for camshaft adjuster. By means of the control 25, a control signal 28 is determined.

The control unit 10a has a supply unit 29 for supplying the components involved with electrical power. The supply unit 29 is supplied by the battery of the motor vehicle with electric power. The supply unit 29 supplies a control / commutation logic 30 and a power electronics 31 with electrical power. From the control signal, the control of the electrical servomotor 32 is generated by means of the control commutation logic 30 and the power electronics 31, here a line 33 with the phase U, a line 34 with the phase V and a line 35 with the phase W.

Hall sensors 36, 37, 38 are provided in the region of the servomotor 32, which are provided by the supply unit 29 with an electrical supply and whose output signals are fed to the control commutation logic via a signal path, a line 39 or several lines. The signals of the Hall sensors 36, 37, 38 are transferred directly or indirectly under conversion, superimposition and / or coding as position information 26 to the central control unit 19a.

According to FIG. 2, an exchange of information takes place between the control unit 10a and the central control unit 19a in the form of the position information via suitable interfaces and intermediate signal connections. In addition, the control unit 10a can transmit diagnostic function signals 40 to the central control unit 19a.

Preferably, a control unit 10a and a camshaft adjuster module 41 are provided, wherein, as shown in FIG. 2, the supply unit 29, the control commutation logic 30 and the power electronics 31 are provided in the control unit 10a, while the electric servomotor 32 and the reverberation Sensors 36-38 are arranged in the camshaft adjuster module 41. The control unit 10a and the camshaft adjuster module 41 communicate with each other via a supply line between the supply unit 29 and the Hall sensors 36-38, the lines 39 and the lines 33-35. The control unit 10a and the camshaft adjuster module 41 may be housed in a common housing or in separate housings, which are preferably mounted on each other.

In contrast to the embodiment shown in FIG. 2, the diagnostic function signal (s) 40 or information, the actuating signal 28 and the position information 26 are not transmitted via separate lines between the central control unit 19b and the control unit 10a, but via the Bus system 11 b.

LIST OF REFERENCE NUMBERS

1 Camshaft adjuster 31 Power electronics

2 cams Wel I enve rstel I e r 32 Actuator

3 camshaft 33 line

4 camshaft 34 line

5 crankshaft 35 line

6 flywheel 36 Hall sensor

7 line 37 Hall sensor

8 line 38 Hall sensor

9 line 39 line position information

10 control unit 40 diagnostic function signal (s)

11 Bus system 41 Camshaft adjuster module

12 clamp

13 clamp

14 clamp

15 donor wheel

16 sensor

17 multi-finger wheel

18 sensor

19 additional control unit

20 sensor

21 signal

22 signal

23 map

24 control variable

25 control unit

26 position information

27 control algorithm

28 control signal

29 supply unit

30 control commutation logic

Claims

claims 1. A device for adjusting a rotational angle of at least one camshaft (3, 4) relative to a crankshaft (5) of an internal combustion engine with - a camshaft adjuster (1, 2), a camshaft adjuster (1, 2) associated control unit (10) and a control unit ( 19), characterized in that in the control unit (19) a control unit (25) is provided with which an actuating signal (28) is determined, which correlates with a desired position of the camshaft adjuster (1, 2). 2. Device according to claim 1, characterized in that a) the camshaft adjuster (1, 2) is designed as an electric camshaft adjuster, b) the control device (19) has a control unit (25), by means of which the actuating signal (28) is determined, which correlates with a desired position of the camshaft adjuster (1, 2), c) there is a signal connection between the control unit (19) and the control unit (10) via which the actuating signal (28) from the central control unit (19) to the Control unit (10) is transmitted and d) the control unit (10) control elements (control commutation logic 30, power electronics 31), by means of which the control signal (28) is convertible into electrical signals, with which a servomotor (32) of the camshaft adjuster (1, 2) is electrically applied, wherein the control elements (control commutation logic 30, power electronics 31) are configured such that the electrical signals e Ine adjusting movement of the camshaft adjuster (1, 2) in the desired position of the camshaft adjuster (1, 2) cause. 3. Device according to claim 1 or 2, characterized in that the central control unit (19) position and / or rotational speed information of one or more sensors (36, 37, 38) of a camshaft adjuster is supplied via one or more separate lines / become. 4. Apparatus according to claim 1 or 2, characterized in that the central control unit (19) position and / or rotational speed information of a sensor or a plurality of sensors (36, 37, 38) of a camshaft adjuster via a common line (39, 26) are supplied and a direction of rotation information is supplied via another line. 5. The device according to claim 4, characterized in that the central control unit (19) position, speed and / or direction of rotation information from sensors of multiple camshaft adjuster (1, 2) are supplied via a common line. 6. Device according to one of the preceding claims, character- ized in that an exchange of signals between the central Control unit (19b) and the control unit (10b) via a bus system (11 b) takes place. 7. Device according to one of the preceding claims, character- ized in that in the central control unit (19) generated actuating signal (28) includes a position and / or speed signal and / or a direction of rotation signal. 8. The device according to claim 7, characterized in that the position ons- and / or speed signal and the direction of rotation signal via separate Lines from the central controller (19) to the control unit (10) are transmitted. 9. Apparatus according to claim 7, characterized in that the positi- Ons and / or speed signal and the direction of rotation signal via a common line from the central control unit (19) to the control unit (10) are transmitted. 10. Device according to one of the preceding claims, characterized in that via a line (40) or a bus system (11b), a signal exchange between the central control unit (19) and the control unit (10) for diagnostic functionalities.