Assembly with control device for a compressor, and compressor, in particular in an automobile

Abstract

Assembly for a compressor, in particular a variable reciprocating piston compressor, for example a refrigerant compressor, in particular in an automobile, which regulates a fluid flow between a high-pressure region and a crankcase pressure region, as well as between the crankcase pressure region and a suction pressure region of the compressor, comprising: a first electric control valve (102) having a valve housing (108) provided with connections for the high-pressure region (104) and for the crankcase pressure region (106), and having a valve body (110) arranged within the valve housing and movable between two positions, the valve body either connecting or separating the two regions depending on the position; a second electric control valve (116) having a valve housing provided with connections for the crank chamber pressure region (118) and for the suction pressure region (120), and having a valve body arranged within the valve housing and movable between two positions, the valve body either connecting or separating the two regions depending on the position; a first temperature sensor (126) that detects a value of a temperature of the refrigerant in the high-pressure region; and a second temperature sensor (128) that detects a value of a temperature of the refrigerant in the suction-pressure region; a first pressure sensor (122) that determines a value of the high pressure in the high pressure region; and a second pressure sensor (124) that determines a value of the suction pressure in the suction pressure region; and an electrical control device, which, during operation of the refrigerant compressor, regulates a fluid flow between the high-pressure area and a crankcase pressure area by means of the position of the valve body of the first control valve, which, depending on the control of the first control valve, regulates the fluid flow between the crank chamber pressure area and a suction pressure area by means of the position of the valve body of the second control valve, wherein at least one of the first and second electric control valves comprises an electric actuator (114) which moves the corresponding valve body between the two positions, wherein the electrical control device is adapted such that the first and second control valves are controlled depending on the determined temperature value of the refrigerant in the high-pressure region and / or the suction pressure region, wherein the electrical control device is adapted such that the first and second control valves are controlled as a function of the determined value of the high pressure and / or the suction pressure.

Description

The present invention relates to an assembly for a compressor, in particular a variable reciprocating piston compressor, for example a refrigerant compressor, in particular in an automobile, which regulates a fluid flow between a high-pressure region and a crankcase pressure region, and between the crankcase pressure region and a suction pressure region of the compressor.Both the design and the mode of operation of refrigerant compressors, in particular of variable reciprocating piston compressors, are known to the person skilled in the art, for example from: DE 10 2011 117 354 A1. In a crankcase of a refrigerant compressor, a plurality of pistons are disposed to pump refrigerant from a suction pressure chamber to a high pressure chamber. The movement of the pistons is thereby guided by a rotating swashplate, as will become apparent from the description which follows.If the swashplate, which is set in rotation, for example, via a belt drive, has a non-zero angle of inclination, this leads to an axial lifting movement of the pistons during a rotation of the swashplate about its axis of rotation. In this case, refrigerant is drawn in from the suction pressure chamber of the refrigerant compressor and pumped into the high-pressure chamber.The suction pressure chamber is connected to the suction-pressure-side connection of the refrigerant compressor, which in turn is connected, in the mounted state in the motor vehicle, to the suction pressure region of the air conditioning circuit, i.e. in particular to the outlet of the evaporator. The high-pressure chamber is connected to the high-pressure-side outlet of the refrigerant compressor, which in turn is connected to the high-pressure region of the air conditioning system, in particular via a heat exchanger (condenser) and an expansion valve, to the inlet of the evaporator.For adapting the delivery volume, in particular for controlling the refrigerant flow, it is already known to vary the angle of inclination of the swashplate in the refrigerant compressor. If, for example, the refrigerant compressor is preset for a maximum delivery volume, a reduction in the angle of inclination of the swashplate causes a reduction in the axial stroke movement of the pistons of the refrigerant compressor and thus a reduction in the delivery volume.It is also known to control the flow of refrigerant in this way by means of a control valve. In this case, the refrigerant flow between the high-pressure region and the crankcase pressure region is controlled by the control valve.The valve is provided with two ports in the valve housing which are connected to the high pressure region and the crank chamber pressure region of the refrigerant compressor. The valve controls the flow of refrigerant between the high pressure region and the crankcase pressure region.If, for example, the valve opens the connection between the high-pressure region and the crank chamber pressure region of the refrigerant compressor, in a first position, refrigerant flows through the control valve from the high-pressure region into the crank chamber pressure region; a pressure increase occurs in the crank chamber pressure region.The valve-controlled increase in pressure in the crank chamber pressure range causes the swash plate to pivot back. The axial stroke movement of the pistons of the refrigerant compressor is thus reduced and the delivery volume of the refrigerant compressor is reduced. Consequently, the pressure in the high pressure region of the air conditioning system does not increase any further.If the valve closes the connection between the high-pressure region and the crank chamber pressure region of the refrigerant compressor, in a further, second position, refrigerant flows from the crank chamber pressure region into the suction pressure region through the permanently open passage (a so-called "bleedport") present in the refrigerant compressor; a pressure drop occurs in the crank chamber pressure region.The valve-controlled pressure drop in the crank chamber pressure range causes the swash plate to pivot out (i.e. tilt). The axial stroke movement of the pistons of the refrigerant compressor is thus increased, and the delivery volume of the refrigerant compressor is increased.The swashplate is usually held in the tilted starting position by spring tension, so that, in the event of a later pressure drop in the crank chamber pressure range, the swashplate pivots back into the starting position and ensures a starting position with respect to the delivery volume in the refrigerant compressor.For reducing the delivery volume of the refrigerant compressor, refrigerant with sufficiently high pressure in the high-pressure region is required in the usual refrigerant compressor. Only at a sufficiently high pressure does this refrigerant flow from the high-pressure region into the crank chamber pressure region by opening the valve and ensures there the reduction of the delivery volume.However, refrigerant with sufficiently high pressure is only available in the high-pressure region when the refrigerant compressor is conveying refrigerant at least temporarily, i.e. the refrigerant compressor has to be operated in the meantime in conveying operation, i.e. with the swashplate pivoted out (i.e. tilted), so that refrigerant is conveyed from the suction pressure region into the high-pressure region and causes a pressure increase there.In other words, such a refrigerant compressor can be operated only for a limited time in a state in which the discharge volume of refrigerant is reduced or the discharge of refrigerant is completely prohibited. Rather, an intermediate delivery operation is required in order subsequently to operate the refrigerant compressor in idle operation, i.e. without delivery volume.Accordingly, the operation of the refrigerant compressor is inefficient even in the idle mode.DE 699 25 653 T2 relates to a method and a device for controlling a variable displacement compressor. A variable displacement compressor in a refrigeration cycle using carbon dioxide as the refrigerant. The compressor changes the inclination of a swash plate located in a control chamber according to the difference between the pressure in the control chamber and the pressure in a suction chamber, thereby varying the displacement of the compressor. The compressor includes a control valve that adjusts the difference between the pressure in the control chamber and the pressure in the suction chamber. The control valve controls the flow rate of the refrigerant supplied from the discharge chamber to the control chamber, thereby adjusting the pressure difference. A controller receives information from outside the cooling circuit. The information from the outside includes the outside temperature, the temperature of a passenger compartment, and a target compartment temperature set by a temperature controller. The controller sets a target value for the pressure of the refrigerant discharged from the compressor according to the information from the outside. The controller then regulates the current supplied to the control valve so that the desired outlet pressure is quickly reached. The compressor reduces unnecessary operations, thereby reducing power consumption and load.DE 10 2012 109 206 A1 discloses a valve-sensor arrangement having an electrically operable valve body and an electric drive configured for this purpose, a local control and regulating device and a communication interface, wherein the electrically operable valve body, the electric drive, the local control and regulating device and the communication interface are arranged within a valve housing, and that sensors can be placed in sensor slots and can be connected to the local control and regulating device of the valve-sensor arrangement via electrical connections arranged on the valve housing, wherein the sensor slots are integrated in the housing wall of the valve housing or are arranged within the valve housing, wherein the sensors are configured as pressure, temperature or combined pressure-temperature sensors.U.S. Pat. No. 6,390,782 B1 discloses a control valve for a variable displacement compressor. A variable control valve for a gas compression system is disclosed for a gas compressor having a variable displacement piston within a compression chamber of the gas compressor. A pressure in a crankcase chamber of the gas compressor acts on the piston. A diaphragm in the control valve controls a flow of high and low pressure gas into and out of the pressure chamber, thereby controlling the displacement of the piston. A predetermined reference pressure in a reference chamber of the control valve acts on the diaphragm. The predetermined reference pressure in the reference chamber is generated by a high and low pressure gas flow into and out of the reference chamber. The predetermined reference pressure may be changed to optimize compressor performance. This gas flow is controlled by reference chamber valve means connected to the reference chamber, the reference chamber valve means being responsive to electrical signals.D4: US 2004 0 018 097 A1 discloses variable displacement compressors that estimate the inclination angle of a plate of the compressor. A variable displacement compressor includes a plate having a variable inclination angle and a piston engaged with the plate. The piston reciprocates in a bore of the compressor in accordance with the rotation of the plate, and the piston has a stroke length determined by the inclination angle of the plate. The compressor also includes a sensor positioned adjacent the piston. The sensor generates an output signal when a predetermined portion of the piston is aligned with the sensor. The compressor also includes a processing unit connected to the sensor. The processing unit estimates the inclination angle of the plate based on the output signal of the sensor.The underlying invention is based on the object of improving the operation of a compressor with an assembly in such a way that the compressor can be operated efficiently, even in a part-load range, that is to say, for example, in a state in which the delivery volume is reduced or the delivery of refrigerant is completely prevented.Furthermore, the object of the invention is to specify a simple and cost-effective possibility for determining the delivery volume, and / or that of a piston stroke and / or the rotational speed and / or the angle of inclination of the swashplate of the refrigerant compressor.The two above objects can be combined, advantageously, with each other in a compressor and are achieved with the invention. However, the two objects can also be achieved independently of one another; they are then based on different inventions which both lead, independently of one another, to a corresponding improvement of a conventional refrigerant compressor.For a better understanding of the present invention, it is explained in more detail with reference to the exemplary embodiments shown in the following figures. Identical parts are provided with identical reference numerals and identical component names. Furthermore, some features or combinations of features from the different embodiments shown and described can also represent independent, inventive or inventive solutions per se. The following are shown: FIGS. 1 a, 1 band 1 c show different perspective views or sectional views of an assembly according to the invention for a refrigerant compressor according to a first exemplary embodiment; FIGS. 2 a, 2 band 2 c show different perspective views or sectional views of a further assembly 200 according to the invention for a refrigerant compressor according to a second exemplary embodiment; FIGS. 3 aand 3 b show different sectional views of a sensor system for a refrigerant compressor; FIGS. 4 aand 4 b show different sectional views of a sensor system for a refrigerant compressor; and FIGS. 5 aand 5 b show different sectional views of a sensor system for a refrigerant compressor.With reference to FIGS. 1 a, 1 band 1 c, the general inventive principle of the assembly 100 for a refrigerant compressor, in particular in an automobile, for optimizing a refrigerant flow from a high-pressure region via a crank chamber pressure region into a suction pressure region during the operation of the refrigerant compressor, will first be explained in more detail below.FIGS. 1 a, 1 band 1 c show different perspective views or sectional views of an assembly 100 according to the invention for a refrigerant compressor according to a first exemplary embodiment. Further developments of the assembly and exemplary embodiments of the individual components of the assembly are explained in more detail in connection with the description.The assembly 100 controls a flow of refrigerant from a high pressure region Pd to a crankcase pressure region Pc of a refrigerant compressor (only a housing portion shown). For this purpose, the assembly comprises a first electric control valve 102.The first electric control valve 102 has a valve housing 108 provided with connections 104, 106 for the high-pressure region Pd and for the crankcase pressure region Pc. The connections 104, 106 of the first control valve 102 communicate in the installed state with the high-pressure region Pd or crankcase pressure region Pc of the refrigerant compressor.In one exemplary embodiment, the valve housing 108 of the control valve 102 already provides the corresponding connections 104, 106 in the uninstalled state. Alternatively, these connections 104, 106 are designed in the form of bores in the section of the housing of the refrigerant compressor which receives as the first regulating valve 102 in the installed state. The valve housing 108 is also formed by the section of the refrigerant compressor housing.Furthermore, the first control valve 102 has a valve body 110 arranged within the valve housing 108 and movable between two end positions. Depending on the position, the valve body 110 connects, disconnects, or partially connects the two regions, namely the high pressure region Pd and the crankcase pressure region Pc.Consequently, in a first maximum open position of the valve body 110 of the first regulator valve 102, a maximum amount of refrigerant flows from the high pressure region Pd into the crankcase pressure region Pc. In a closed, second end position of the valve body 110, any refrigerant flow between the two regions of the first control valve 102 is prevented. The control valve 102 can also assume any desired positions between the two end positions in which the refrigerant flow is then correspondingly metered or regulated.In an advantageous development of the control valve 102, the valve body 110 can also assume further positions lying between the end positions within the valve housing 108.Consequently, the valve body 110 occupies not only the two positions in which the high pressure region Pd and the crankcase pressure region Pc are connected or disconnected from each other, but also other positions in which the high pressure region Pd and the crankcase pressure region Pc are connected to each other, but the flow rate of refrigerant is restricted.In one exemplary embodiment, the valve body 110 comprises a shut-off body (or sealing body) 112 which is configured to be needle-shaped, plate-shaped, piston-shaped, conical or spherical. In the illustrated embodiment, the shut-off body is formed in the shape of a needle.The assembly 100 according to the invention furthermore controls a refrigerant flow from the crank chamber pressure region Pc into a suction pressure region Ps of the refrigerant compressor. For this purpose, the assembly 100 additionally comprises a second electric control valve 116The second electric control valve 116 is provided with ports 118, 120 for the crank chamber pressure region Pc and for the suction pressure region Ps. The connections 118, 120 of the second control valve 116 communicate in the installed state with the crankcase pressure region Pc or the suction pressure region of the refrigerant compressor.The above explanations regarding the first control valve 102 also apply in a corresponding application to the second control valve 116, so that depending on the position of a valve body arranged within a valve housing and movable between two positions, the latter either connects the crank chamber pressure range Pc and the suction pressure range Ps to one another or separates them from one another or partially separates them from one another.Furthermore, the assembly 100 according to the invention comprises an electrical regulating device (not shown). This control device controls the first electrical control valve 102 and the second electrical control valve 116 and can be formed in the form of a processor, a microcontroller, a field-programmable gate array (FPGA), or a different type of arithmetic unit. The control device can also comprise further parts, such as a driver for the actuator, etc.During operation of the refrigerant compressor, the electrical control device controls a refrigerant flow between high-pressure region Pd and a crank chamber pressure region Pc via the position of the valve body 110 of the first control valve 102. For this purpose, the electrical control device transmits an (electrical) signal to the first electrical control valve 102 that specifies the corresponding position of the valve body 110.Furthermore, during operation of the refrigerant compressor, the electrical control device controls the refrigerant flow between the crank chamber pressure range Pc and the suction pressure range Ps via the position of the valve body of the second control valve. For this purpose, the electrical control device transmits an (electrical) signal to the first electrical control valve 116 that specifies the corresponding position of the valve body.Advantageously, the control of the second valve body 116 is carried out by the electrical control device according to the invention as a function of the control of the first control valve 102, i.e. the position of the valve body of the second control valve is matched to the position of the valve body of the first control valve.This dependent control of the second control valve 116 takes place during the operation of the refrigerant compressor, i.e. both during the conveying operation and during the idling operation of the refrigerant compressor.In the delivery operation, the refrigerant compressor delivers refrigerant from the suction pressure region Ps into the high pressure region Pd.For this purpose, the control device controls the position of the first control valve 102 such that the high-pressure region Pd is separated from the crankcase pressure region Pc. Refrigerant does not flow into the crank chamber pressure region Pc in this position.At the same time, the control device controls the position of the second control valve 116 such that the crankcase pressure range Pc is connected to the suction pressure range Ps. The refrigerant still located in the crank chamber pressure region flows in this position into the suction pressure region Ps.For this purpose, the control device controls the position of the first control valve 102 such that the high-pressure region Pd is connected to the crankcase pressure region Pc. Refrigerant flows into the crank chamber pressure region Pc in this position, so that the swash plate pivots back to a non-tilted position.At the same time, the control device controls the position of the second control valve 116 such that the crankcase pressure range Pc is separated from the suction pressure range Ps. The refrigerant in the crank chamber pressure region does not flow into the suction pressure region Ps in this position; at the same time, however, the swash plate cannot pivot out into the tilted starting position and remains in the non-tilted position.Thus, by means of the regulation according to the invention with the regulating device, an efficiency gain is realized during operation of the refrigerant compressor. The design-related disadvantages of a conventional refrigerant compressor are compensated for by the invention.In an advantageous development, the assembly comprises a first electrical interface (not shown), via which a cooling capacity for the refrigerant is predefined during operation (i.e. delivery operation or idling operation) of the refrigerant compressor. The electrical regulating device is adapted in such a way that the first and second regulating valves 102, 116 are regulated as a function of the cooling power predefined via the first electrical interface.In an exemplary embodiment of the assembly 100 according to the preceding development, the first electrical communication interface is provided, via which the cooling power is predefined, is designed as a controller area network, CAN, data bus.Further exemplary embodiments of the first electrical interface comprise a configuration by means of which the cooling power is predefined, as a serial peripheral interface (SPI) data bus, as an inter-integrated circuit (I2C) data bus, as a local interconnect network (LIN) data bus.In a further advantageous refinement, the assembly 100 comprises a second electrical interface via which the assembly is supplied with voltage. The second electrical interface can be separate or integrated into the first electrical interface.In the embodiment of the assembly 100 according to the invention, at least one of the first and second electrical control valves 102, 116 comprises an actuating drive 114, which moves the corresponding valve body between the two positions. Embodiments of the electric actuator 114 include a stepper motor, a DC motor, a servo motor, electric lifting solenoids, and a piezoelectric actuator.According to the invention, the assembly 100 comprises a first pressure sensor 122, which determines a value of the high pressure in the high-pressure region Pd; and / or a second pressure sensor 124, which determines a value of the suction pressure in the suction pressure region Ps.The electrical regulating device is adapted in such a way that the first and second regulating valves 102, 116 are actuated as a function of the ascertained value of the high pressure and / or of the suction pressure.According to the present invention, the assembly 100 includes a first temperature sensor 126 that determines a value of a temperature of the refrigerant in the high pressure region Pd; and / or a second temperature sensor 128 that determines a value of a temperature of the refrigerant in the suction pressure region. The electrical control device is adapted in such a way that the first and second control valves 102, 116 are controlled as a function of the determined temperature value of the refrigerant in the high-pressure region Pd and / or the suction pressure region Ps.The sensors 122, 124, 126, and 128 provide the value of the suction pressure, the value of the high pressure, the value of the temperature in the suction pressure range, and the value of the temperature in the high pressure range. These values can be used by the electrical control device to determine the mass flow in the refrigerant circuit.The following advantages can be mentioned for a calculation of the mass flow: the torque of the refrigerant compressor can be calculated with the aid of the mass flow. If the current or future torque of the refrigerant compressor is known, the injection quantity in the automobile can be matched more precisely, which leads to fuel savings and thus to CO2 reductions.Furthermore, in controlled belt tensioning devices in the automobile, the belt tension at known torque can be adjusted according to requirements. This is advantageous because frictional forces are reduced and the service life of the belt bearings is increased.In a possible embodiment of the assembly 100, the electrical regulating device is adapted in such a way that, when the refrigerant compressor is out of operation (i.e. is neither in the delivery mode nor in the idling mode), the first and the second regulating valves 102, 116 are each actuated in such a way that the valve body of the first 110 and of the second regulating valves 102, 116 simultaneously assume a position in which the corresponding high-pressure and suction pressure ranges are connected to one another via the crank chamber pressure range.More efficient operation of the refrigerant compressor is possible. The design-related disadvantages of a conventional refrigerant compressor are compensated for by the invention.FIGS. 2 a, 2 band 2 c show different perspective views or sectional views of a further exemplary assembly 200 for a refrigerant compressor. As already explained in connection with FIGS. 1 a, 1 band 1 c, this assembly 200 likewise comprises a first control valve 102, a second control valve 116 and an electrical control device (not shown). Reference is made at this point only to corresponding detailed explanations in this respect.The assembly 200 differs solely in its arrangement with respect to the portion of the refrigerant compressor housing. Here, a vertical arrangement of the assembly 200 with respect to the selected refrigerant compressor housing is a horizontal arrangement, rather than as shown in connection with assembly 100. In this case, the construction depth of the refrigerant compressor with the assembly 200 can be reduced in an advantageous manner in the installed state.With reference to FIGS. 3 aand 3 b, the general principle of a sensor system 300 for determining a rotational speed and a tilt angle of a swash plate in a refrigerant compressor, in particular in an automobile, will first be explained in more detail below.FIGS. 3 aand 3 b show a sensor system 300 in connection with a refrigerant compressor. Further developments of the sensor system and exemplary embodiments of the individual components of the sensor system are explained in more detail in connection with the description.The underlying refrigerant compressor comprises a swashplate which is mounted in a tiltable manner on a drive shaft and is driven by the latter and is thus set in rotation.In an exemplary embodiment of the refrigerant compressor, the drive force is transmitted from the drive shaft of the refrigerant compressor to a rotatable driver disk. A driver arm arranged on the driver disk, which runs axially parallel to the drive shaft, transmits the drive force via a pivotably mounted connecting element to the swashplate of the compressor.The swash plate of the refrigerant compressor is in turn connected to a plurality of pistons via plain bearings. Thus, a swash plate pivoted out at a non-zero angle of inclination moves the connected pistons in an axial stroke movement during a revolution about the axis of rotation. The angle of inclination of the swash plate thus determines the stroke of the pistons and thus the delivery volume of the refrigerant compressor.The sensor system 300 includes a position transducer 302 that is mechanically coupled to the swashplate such that the position transducer 302 performs a cyclical movement within a housing of the refrigerant compressor that is dependent on and guided by the rotational and tilting movement of the swashplate.Cyclical movement of the position transducer 302 describes, in the context of the invention, a movement which repeats as a function of a revolution of the swashplate about its axis of rotation.In this case, the position transmitter 302 can either be guided in a recurring wobbling or tilting movement about the axis of rotation, guided on a recurring circular path about the axis of rotation, or else guided in a recurring lifting movement parallel to the axis of rotation. The cyclical movement of the position transducer 302 merely needs to be dependent on the rotational movement of the swashplate and allow conclusions to be drawn about the angle of inclination of the latter.According to one example, the locator is mechanically connected to the swashplate and performs a motion corresponding to the rotational and tilting motion of the swashplate.In this case, the position transducer 302 can be mechanically connected to a pivotably mounted connecting element, via which the swashplate is driven (as shown in FIGS. 3 aand 3 b ). Alternatively, the locator 402 may also be integrated into the swashplate (as shown in FIGS. 4 aand 4 b ).According to an alternative exemplary embodiment, the position transducer is mechanically connected to a piston of the refrigerant compressor coupled to the swashplate, and executes a translatory (or stroke) movement which is dependent on the rotational and tilting movement of the swashplate and runs substantially parallel to the drive shaft.In this case, the position transducer can be mechanically connected to a connecting element via which the piston is connected to the swashplate (not shown). Alternatively, the position transducer 502 may also be integrated in the piston (as shown in FIGS. 5 a, b).The sensor system 300 further includes a position sensor 304 mechanically coupled to the housing of the refrigerant compressor. The position sensor 304 thus represents a fixed reference point for a distance determination, with respect to which the movement of the position transmitter 302 can be tracked, i.e. determined.The position sensor 304 is advantageously arranged in such a way that at at least one time this position sensor 304 is at a small distance from the position transducer 302 with respect to its guided cyclical movement.If it is assumed according to an exemplary embodiment that the position transmitter 302 is guided about the axis of rotation in a recurring wobbling or tilting movement-as shown in FIGS. 3 aand 3 b-the required small distance from the position transmitter corresponds to an arrangement of the position sensor 304 in an extension (i.e. aligned) with at least one point of the axis of rotation.If, according to another exemplary embodiment, it is assumed that the position transmitter 302 is guided around the axis of rotation on a recurrent circular path, as shown in FIGS. 4 aand 4 b, the small distance from the position transmitter corresponds to an arrangement of the position sensor 404 in the extension (i.e. aligned) with at least one point on the axis of rotation.If, according to a further exemplary embodiment, it is assumed that the position transmitter 502 is guided substantially parallel to the drive shaft in a repeated translatory (or stroke) movement, as shown in FIGS. 5 aand 5 b, that is to say the small distance from the position transmitter of an aligned arrangement of the position sensor 504 alongside at least one position of the movement.The position sensor 304 of the sensor system 300 according to the invention continuously determines a distance between position transducer 302 and position sensor 304.Furthermore, the position sensor 304 of the sensor system 300 according to the invention comprises an evaluation device (not shown). The evaluation device can be formed in the form of a processor, a microcontroller, a field-programmable gate array, FPGA, or a different type of arithmetic unit.The evaluation device selects a minimum distance between position transmitter and position sensor from a plurality of the continuously determined distances. This selected minimum distance is then used to determine a tilt angle from its amplitude and a rotational speed of the swashplate from the time intervals between two successive selected minimum distances.In other words, the expansion device determines the angle of inclination and the rotational speed of the swash plate of the refrigerant compressor from the distance signal between position sensor 302 and position sensor 304 determined by the position sensor 304.For this purpose, the evaluation device selects those distance values in the distance signal which correspond to a minimum distance with respect to a time horizon. The time horizon referred to can advantageously be selected as the time duration of a revolution of the swashplate about its axis of rotation, and is thus dependent on the rotational speed. This requires an estimate which can also take into account, for example, the history of earlier rotational speeds. Consequently, the time horizon is continuously adjusted.The distance values selected in the evaluation device correspond to that (single) position of the position transmitter 302 which the position transmitter 302 assumes on its cyclically guided movement with the smallest distance from the position sensor 304. In the cyclical movement, the position transducer 302 does not move away from the position sensor 304 until it approaches the position sensor 304 again, corresponding to the rotational movement of the swashplate.Thus, the time duration between two successive selected minimum distance values allows the rotational speed of the swashplate to be determined. Furthermore, the evaluation device determines the angle of inclination of the swashplate via the amplitude of a selected minimum distance value.Advantageously, the position sensor 304 is disposed at the position where the displacement due to the tilting motion of the swash plate is the largest. In other words, the locator 302 is mechanically coupled to the swashplate such that the locator experiences a maximum deflection due to the tilting motion of the swashplate.According to an advantageous exemplary embodiment, the position sensor 302 of the sensor system 300 according to the invention is designed as a magnet and the position sensor 304 of the sensor system 300 according to the invention is designed as a Hall effect sensor. Other configurations of the sensors are possible.In an advantageous development of the sensor system 300, the position sensor 304 is formed with a housing having a screw thread and is screwed into a threaded bore formed in the housing of the refrigerant compressor. In this case, the threaded bore formed in the housing can be formed as a through bore or a blind bore.Advantageously, the speed and the compression volume can be determined by the corresponding sensor system 300. If the angle of inclination and the rotational speed are determined, an electrical control device provided in the refrigerant compressor or the above-described electrical control device of the assembly 100 or 200 can use the latter in order to determine the mass flow in the refrigerant circuit.For such a calculation of the mass flow, the following advantages can be mentioned: the torque of the refrigerant compressor can be calculated with the aid of the mass flow. If the current or future torque of the refrigerant compressor is known, the injection quantity in the automobile can be matched more precisely, which leads to fuel savings and thus to CO2 reductions.Furthermore, in controlled belt tensioning devices in the automobile, the belt tension at known torque can be adjusted according to requirements. This is advantageous because frictional forces are reduced and the service life of the belt bearings is increased.FIGS. 4 aand 4 b show a sensor system 400 according to the invention in conjunction with a refrigerant compressor. The sensor system includes a position transducer 402 and a position sensor 404 that provide the same functionality as the corresponding position transducer 302 and position sensor 304. Reference is made at this point only to corresponding detailed explanations in this respect.The sensor system 400 differs from the sensor system 300 solely in the arrangement of the position sensor 402 and the position sensor 404 in / on the refrigerant compressor. In particular, position transducer 402 is integrated in swashplate in sensor system 400. Correspondingly, in this example, the position sensor 404 is arranged in the sensor system at a small distance from the position transducer 402, namely in the extension (i.e. aligned) with at least one point on the axis of rotation on the refrigerant compressor housing wall.The advantages set out above are also realized in this way, since the rotational speed and the angle of inclination of a swashplate in a refrigerant compressor is determined sufficiently precisely also in this arrangement of the sensor system 400 in / on the refrigerant compressor.FIGS. 5 aand 5 b show a sensor system 500 according to the invention in conjunction with a refrigerant compressor. The sensor system includes a position transducer 502 and a position sensor 504 that provide the same functionality as the corresponding position transducer 302 and position sensor 304. Reference is made at this point only to corresponding detailed explanations in this respect.The sensor system 500 differs from the sensor system 300 solely in the arrangement of the position sensor 502 and the position sensor 504 in / on the refrigerant compressor. In particular, in the sensor system 500, the position sensor 502 is integrated into the piston of the refrigerant compressor. Correspondingly, the position sensor 504 in the sensor system is arranged at a small distance from the position transmitter, namely in an aligned arrangement alongside at least one position of the movement on the refrigerant compressor housing wall.The advantages set out above are likewise realized in this way, since the rotational speed and the angle of inclination of a swashplate in a refrigerant compressor is determined sufficiently precisely also in this arrangement of the sensor system 500 in / on the refrigerant compressor.List of reference numbers:100, 200 Assembly 102 First control valve 104 Connection for the high-pressure region 106 Connection for the crankcase pressure region 108 Valve housing 110 Valve body 112 Shut-off body 114 Electrical actuating drive 116 Second control valve 118 Connection for the crankcase pressure region 120 Connection for the suction pressure region 122 First pressure sensor for the high-pressure region 124 Second pressure sensor for the suction pressure region 126 First temperature sensor for the high-pressure region 128 Second temperature sensor for the suction pressure region 300, 400, 500 Sensor system 302, 402, 502 Position sensors 304, 404, 504 Position sensor

Claims

Assembly for a compressor, in particular a variable reciprocating piston compressor, for example a refrigerant compressor, in particular in an automobile, which regulates a fluid flow between a high-pressure region and a crank chamber pressure region, and between the crank chamber pressure region and a suction pressure region of the compressor, comprising: a first electrical regulating valve (102), which has a valve housing (108) provided with connections for the high-pressure region (104) and for the crank chamber pressure region (106), and which has a valve body (110) arranged within the valve housing and movable between two positions, wherein the valve body either connects the two regions to one another or disconnects them from one another depending on the position; a second electric control valve (116) comprising a valve housing provided with connections for the crank chamber pressure region (118) and for the suction pressure region (120), and a valve body arranged within the valve housing and movable between two positions, the valve body either connecting or disconnecting the two regions to one another depending on the position; a first temperature sensor (126) which determines a value of a temperature of the refrigerant in the high pressure region; and a second temperature sensor (128) which determines a value of a temperature of the refrigerant in the suction pressure region; a first pressure sensor (122) which determines a value of the high pressure in the high pressure region; and a second pressure sensor (124) which determines a value of the suction pressure in the suction pressure region; and an electric control device, which during operation of the refrigerant compressor regulates a fluid flow between high-pressure region and a crankcase pressure region by means of the position of the valve body of the first regulating valve, said fluid flow regulating the fluid flow between the crankcase pressure region and a suction pressure region by means of the position of the valve body of the second regulating valve as a function of the actuation of the first regulating valve, wherein at least one of the first and second electrical regulating valves comprises an electrical actuating drive (114) which moves the corresponding valve body between the two positions, wherein the electrical regulating device is adapted in such a way that the first and second regulating valves are actuated as a function of the determined temperature value of the refrigerant in the high-pressure region and / or the suction pressure region, wherein the electrical regulating device is adapted in such a way, the first and second control valves being controlled as a function of the determined value of the high pressure and / or of the suction pressure.Assembly according to claim 1, wherein it further comprises: a first electrical interface via which a cooling power for the fluid, in particular refrigerant, is predetermined during operation of the compressor, and / or a second electrical interface via which the assembly is supplied with voltage; and wherein the electrical control device is adapted such that the first and second control valves are controlled as a function of the cooling power predetermined via the first electrical interface.The assembly according to claim 2, wherein: the first electrical interface is configured as a data bus.The assembly of claim 1, wherein: the first and / or second control valve comprises a valve body; and the position of the valve body is determined with an electrical position sensor.Assembly according to claim 1, wherein: the first and / or second control valve has a valve body and the position of the valve body is determined as a function of one or more control variables present at the electric actuating drive.The assembly according to claim 1, wherein: the high pressure region is hermetically sealed by means of: - a bellows seal and / or - an encapsulation provided in the electric actuator (114) and / or - a sealing device for the electric interface.The assembly of claim 1, wherein: the electric actuator (114) displaces the valve body of the first or second control valve in the increments predetermined by the actuator.Compressor, in particular for an automobile, comprising: an assembly which controls a refrigerant flow between a high-pressure region and a crankcase pressure region and between the crankcase pressure region and a suction pressure region of the refrigerant compressor, wherein the assembly is configured according to one of Claims 1 to 7.

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