DE102017102645B4 - Refrigerant Scroll Compressor for use inside a heat pump - Google Patents

Abstract

Refrigerant scroll compressor (1) for use within a heat pump with CO's refrigerant, comprising • a compressor housing (2), • two spirals (3; 7) nested within the compressor housing (2), one spiral (3) of which is stationary and the other scroll (7) is eccentrically movable in a circular path, whereby the volume of a plurality of different compression chambers (8, 9, 10) formed between the scrolls (3; 7) changes cyclically, the individual scrolls (3; ) each have a total winding angle in the range of 440 ° to 900 ° and between the spirals (3; 7) the following compression chambers (8, 9, 10) are formed: ➢a compression chamber as a suction pressure chamber (8) for the suction of refrigerant , which is divided into an inner suction chamber (8.1) and an outer suction chamber (8.2), ➢a central compression chamber (9), in an inner middle compression chamber (9.1) and an eu is divided ere average compression chamber (9.2), ➢eine refrigerant outlet chamber (10), in which the two inner end portions (3a; 7a) of the spirals (3; 7) are opposite each other, • two or more refrigerant outlets (4.1; 4.2) in a wall (2a) of the compressor housing (2) facing the spirals (3; 7), • one or more valves ( 6) for the opening and closing of the two refrigerant outlets (4.1; 4.2) and • a main refrigerant outlet (5) in the wall (2a) of the compressor housing (2) in the center of the stationary housing (2) facing the spirals (3; Spiral (3), which is always open and has no valve.

Description

The invention relates to a refrigerant scroll compressor for use within a heat pump with CO ₂ as the refrigerant. Furthermore, the invention relates to the use of this refrigerant scroll compressor in a refrigerant circuit with CO ₂ as refrigerant, which is operable in the air conditioning mode and / or in the heat pump mode. Field of application of the invention are in particular electric refrigerant compressors in motor vehicles.

The term scroll compressor is the common name in the jargon for a type of compressor, which is known, inter alia, under the names gear worm compressor, scroll compressor or scroll compressor. A scroll compressor works on the displacement principle. It consists of two nested spirals, one of which is stationary and the other is moved eccentrically on a circular path. The spirals keep a minimum distance from each other and form ever smaller compression chambers with each revolution. As a result, the gas to be pumped is sucked in from the outside, compressed within the scroll compressor in the compression chambers and ejected via a connection in the center of the coil.

Refrigerant scroll compressors for air conditioning refrigerant circuits currently in use are designed to operate with high efficiency in air conditioning mode. The goal is the lowest possible energy consumption with a simultaneously high refrigerant mass flow. This leads to low discharge temperatures at a certain pressure and speed.

In a heat pump cycle, it is necessary to reach high outlet temperatures to heat the passenger compartment. In this case, a scroll compressor is required, which is as effective as possible at high pressure conditions in order to achieve a high outlet temperature. At higher pressures, the isentropic efficiency decreases, causing the compressors to operate less efficiently. Also, the bearing load increases.

Conventional scroll compressors with a wrap angle in the range of 440 ° to 900 ° require two outlets and one main outlet to work efficiently. Each outlet closes with a valve after the pressure in the compression chamber drops under high pressure. This prevents hot gas from flowing back into the compression chamber and causing the compressor to lose efficiency. Air conditioning compressors usually have three exhaust valves, so-called three-finger valves on.

When an air conditioning compressor is designed to operate efficiently under air conditioning conditions, this is often associated with the disadvantage that this compressor is significantly less effective under heat pump conditions. Thus, for a scroll compressor operating in heat pump mode, where high exit temperatures are needed, it is very advantageous for hot gas to flow back into the compression chamber.

In the JP 2002-070765 A a scroll compressor with a bypass mechanism is described, which is intended to avoid overpressure in the scroll compressor. The mechanism requires an open spiral geometry with a large dead space volume in the middle of the scoll. Because of the open scroll geometry in the scroll center only low compression ratios can be achieved. Therefore, high-pressure conditions with a high compression ratio, that is, a ratio of high pressure / suction pressure> 3.7, for heat pump conditions are not possible.

From the DE 10 2014 211 123 A1 For example, there is disclosed a method of manufacturing a rotation preventing ring of a scroll compressor, wherein the rotation preventing ring is made of a metal and provided in a rotation preventing mechanism for preventing the rotation of a movable scroll about its own axis. The method includes the steps of: drawing a steel plate by pressing to produce a first intermediate body having a bottomed cylindrical shape; Punching the bottom of the first intermediate body to produce a second intermediate body; and ring forming the second intermediate body. Furthermore, disclosed is a rotation preventing mechanism of a scroll compressor with the rotation preventing ring, which is manufactured by said method for producing the rotation preventing ring of the scroll compressor; and a pin which is inserted into the rotation preventing ring and in sliding contact with the inner peripheral surface of the rotation preventing ring. At this time, a ridge line is formed in the circumferential direction in the inner peripheral surface of the rotation preventing ring in the manufacturing process, the outer peripheral surface of the pin being inserted in the axial direction thereof at a position where the outer peripheral surface of the pin crosses the ridge line in the rotation preventing ring.

In the DE 603 00 376 T2 describes a scroll compressor whose elastic member can be manufactured at a relatively low cost. The scroll compressor includes a housing. A fixed scroll member is mounted in the housing and has a fixed base plate and a fixed spiral wall extending from the stationary base plate. The movable scroll member is placed in the housing and has a movable base plate and a movable spiral wall extending from the movable base plate. The movable spiral wall is in abutment with the fixed spiral wall. A compression chamber is defined between the movable spiral wall and the fixed spiral wall. The compression chamber is gradually reduced in volume as refrigerant in the compression chamber is gradually compressed and moved by an orbital motion of the movable scroll member relative to the fixed scroll member toward a center side of the spiral walls. An elastic member is formed in an annular and planar shape and is fixed in the housing on one side of a rear surface of the movable base plate to slidably contact the rear surface of the movable base plate in a sliding portion of the elastic member. A front wall is provided on a side opposite to one side of the movable scroll member with respect to the elastic member. A first space is formed between the elastic member and the front wall to allow the elastic member to be elastically deformed. The elastic member is elastically deformed by pressure-contacting the movable scroll member toward the front wall, thereby pushing the movable scroll member toward the fixed scroll member.

The EP 2 618 000 B1 discloses a motor-driven compressor having a differential pressure control valve disposed in a fluid passage for fluid flowing through a compressor. The differential pressure regulating valve is provided with a valve chamber formed in the fluid passage and having a cylindrical shape; a valve hole formed in the fluid passage as an opening communicating with the valve chamber; a valve body disposed in the valve chamber and adapted to open and close the valve hole; a support member fixedly mounted to the valve chamber and extending transversely to a flow direction of the fluid in the valve chamber, the support member having a connection passage for fluid communication between a first valve chamber formed on the side of the valve body of the support member in the valve body; and a second valve chamber formed on the opposite side of the support member in the valve chamber, wherein at least a part of the connection passage is opened at evenly spaced intervals to the outer periphery of the support member on the side of the first valve chamber; and a driving member disposed between the support member and the valve chamber for driving the valve body in the direction of the valve hole, wherein the driving member is extendable. The support member has a projection extending in the same direction as the extension and compression direction of the driving member and with which the valve body can contact when the driving member is compressed, the connection passage opening at the center of a contact portion of the projection to which the valve body may contact, and has a plurality of recesses extending radially to the protrusion from the opening.

From the EP 2 218 914 A2 discloses a scroll-type fluid machine comprising: a fixed scroll and a movable scroll engaged with each other; an anti-rotation mechanism for preventing rotation of the movable scroll about its own axis; and a drive mechanism for driving the movable scroll in an orbital motion relative to the fixed scroll. In this case, the drive mechanism comprises: a drive shaft which is rotatable on a first axis; an eccentric pin rotating with rotation of the drive shaft about the first axis, the eccentric pin having an outer peripheral surface centered on a second axis parallel to and eccentric to the first axis; and a bearing attached to the movable scroll, the bearing having an inner peripheral surface centered on a third axis parallel and eccentric to the first and second axes, the inner peripheral surface being in contact with the outer peripheral surface of the eccentric pin wherein, due to the arrangement of the first, second and third axes, a compressive force is exerted by the eccentric pin on the bearing to urge the movable scroll onto the fixed scroll.

In the EP 2 012 016 A1 there is described a scroll-type fluid machine having a movable scroll having pressure chambers between the movable scroll and a fixed scroll and revolving with respect to the fixed scroll. Furthermore, the fluid machine has a support wall provided for the housing and supporting the thrust load transmitted from the movable scroll. In addition, the fluid machine comprises a thrust bearing, which is placed between the movable scroll and the support wall. The thrust bearing includes an annular support surface formed in the support wall, a holding plate fixed to the support surface, a holding hole formed in the holding plate opened in both sides of the holding plate, and a pressure receiving piece held in the holding hole and in surface contact with both the support surface as well as with the movable spiral is brought.

In the EP 1 464 840 A1 there is disclosed a scroll compressor having a suction chamber, a stationary scroll and a movable scroll. The stationary scroll includes a peripheral wall and a stationary scroll section. The movable scroll has a movable base plate and a movable spiral section. A peripheral surface of the movable base plate and an inner surface of the peripheral wall form a sealing portion at portions closely spaced close to each other. The seal portion moves along the inner surface of the peripheral wall as the movable scroll rotates. In a bottom portion of a suction chamber, lubricating oil is supplied to a compression chamber defined by the spiral portions of the suction chamber. Thus, lubricating oil can be used, which is retained in the bottom of the suction chamber

The object of the invention is to provide a scroll compressor which has high efficiency in both heat pump and air conditioning modes.

The object is achieved by a refrigerant scroll compressor with the features of claim 1. Further developments are specified in the dependent claims.

• • ein Verdichtergehäuse,
• • zwei innerhalb des Verdichtergehäuses ineinander verschachtelte Spiralen, von denen eine Spirale stationär ist und die andere Spirale auf einer kreisförmigen Bahn exzentrisch bewegbar ist, wodurch sich das Volumen von mehreren verschiedenen zwischen den Spiralen ausgebildeten Verdichtungskammern zyklisch ändert, wobei die einzelnen Spiralen jeweils einen Gesamt-Umwicklungswinkel im Bereich von 440° bis 900°, vorzugsweise 580° bis 700°, aufweisen und zwischen den Spiralen die folgenden Verdichtungskammern ausgebildet sind:
  • ➢eine Verdichtungskammer als Saugdruckkammer für das Ansaugen von Kältemittel, die in eine innere Ansaugkammer und eine äußere Ansaugkammer, je nach Position der jeweiligen Ansaugkammer bezüglich der beweglichen Spirale, aufgeteilt ist,
  • ➢eine mit der Saugdruckkammer verbundene mittlere Verdichtungskammer, die in eine innere mittlere Verdichtungskammer und eine äußere mittlere Verdichtungskammer, je nach Position der jeweiligen Verdichtungskammer bezüglich der beweglichen Spirale, aufgeteilt ist,
  • ➢eine Kältemittelaustrittskammer, die mit der mindestens einen mittleren Verdichtungskammer verbunden ist und in der sich die beiden inneren Endbereiche der Spiralen gegenüberliegen,
• • zwei oder mehrere Kältemittel-Vorauslässe in einer zu den Spiralen stirnseitigen Wand des Verdichtergehäuses,
• • ein oder mehrere Vorauslassventile für das Öffnen und Schließen der beiden Kältemittel-Vorauslässe, und
• • einen Kältemittel-Hauptauslass in der zu den Spiralen stirnseitigen Wand des Verdichtergehäuses am Zentrum der stationären Spirale, der stets geöffnet ist und kein Ventil aufweist.

The scroll compressor according to the invention is suitable for use within a heat pump with CO ₂ as a refrigerant. Refrigerant scroll compressor for use within a heat pump with CO ₂ as the refrigerant, comprising

• A compressor housing,
• Two spirals interleaved within the compressor housing, one spiral being stationary and the other spiral being eccentrically movable on a circular path, whereby the volume of several different compression chambers formed between the spirals changes cyclically, the individual spirals each having a total Winding angle in the range of 440 ° to 900 °, preferably 580 ° to 700 °, and between the spirals, the following compression chambers are formed:
  • ➢a compression chamber as a suction pressure chamber for the suction of refrigerant, which is divided into an inner suction chamber and an outer suction chamber, depending on the position of the respective suction chamber with respect to the movable spiral,
  • ➢an intermediate compression chamber connected to the suction pressure chamber divided into an inner middle compression chamber and an outer middle compression chamber, depending on the position of the respective compression chamber with respect to the movable spiral,
  • ➢a refrigerant discharge chamber which is connected to the at least one middle compression chamber and in which the two inner end regions of the spirals face each other,
• Two or more refrigerant outlets in a wall of the compressor housing facing the spirals,
• • one or more blow-off valves for opening and closing the two refrigerant outlets, and
• • a main refrigerant outlet in the spiral wall of the compressor housing at the center of the stationary scroll, which is always open and has no valve.

The invention also relates to the use of the above-mentioned refrigerant scroll compressor in a refrigerant circuit with CO ₂ as the refrigerant, which is operable in the air conditioning mode and / or in the heat pump mode.

With the inventive design of the refrigerant scroll compressor high pressure is achieved under air conditioning conditions, even before the refrigerant can escape through the main outlet. Therefore, no valve is required at the refrigerant main outlet. In particular, the shape of the spirals has the consequence that the main outlet valve is dispensable. In a particularly preferred embodiment of the invention, the individual spirals each have a total winding angle of 660 °. Preferably, the spirals are formed with respect to their spiral geometry such that they allow a reduction of the volume of the refrigerant outlet chamber to a dead space volume which is ≦ 9% of the suction volume or stroke volume of the scroll compressor. In a particularly preferred embodiment, the spirals are formed with respect to their spiral geometry such that they allow a reduction in the volume of the refrigerant outlet chamber to a dead space volume corresponding to a volume of ≤ 5.0% of the intake volume, for example to 4.9% of the intake volume. With a suction volume of 6 cm ³ , this would correspond to a dead space volume of about 0.3 cm ³ .

In heat pump mode, the refrigerant outlets remain mostly closed and all refrigerant exits through the main refrigerant outlet. The backflow from the high pressure side leads at low pressure conditions to a deteriorated compression and high Austrittstem peratu ren.

In an advantageous embodiment of the invention, the bores of the refrigerant Inlets and the refrigerant main outlet arranged substantially linearly and equidistantly from each other, with the main outlet in the middle and the refrigerant outlets are placed symmetrically thereto. The middle compression chamber is divided into two middle compression sub-chambers, which are advantageously positioned symmetrically to each other. Depending on the position with respect to the movable spiral, there are always an outer and an inner compression chamber. That is, the outer compression chamber is adjacent to the convex side and the inner compression chamber is adjacent to the concave side of the movable scroll. The bores of the refrigerant outlets are at least temporarily in the region of the middle compression chamber, wherein at least one bore in the region of the outer compression chamber and the same number of bores in the region of the inner compression chamber. Linear and symmetrical arrangement of the refrigerant spool holes and the main outlet allow the internal and external compression chamber bleed valves to open or close together at the same compression pressure and to provide transfer to the main refrigerant outlet.

As a valve for opening and closing the two refrigerant outlets is particularly suitable a U-shaped or V-shaped valve, with the U- or V-legs, the refrigerant feeds can be closed, while the opened refrigerant main outlet preferably between the U- or V-legs is positioned.

Another advantage of the invention is that the compressor can be operated in heat pump mode at low pressure and at lower compressor speeds. This results in an improved NVH, that is, a reduction in vehicle vibration perceivable as noise or vibration, as well as lower energy consumption and lower bearing loads, resulting in longer bearing life or the possibility of reducing bearing size. Also, the required exhaust valve is cheaper.

• 1A: einen Ausschnitt aus einem Scrollverdichter mit der stationären Spirale und Kältemittel-Auslassbohrungen in der zur Spirale stirnseitigen Wand des Scrollverdichter-Gehäuses als Innenansicht,
• 1B: die stirnseitige Wand des Scrollverdichter-Gehäuses mit den Kältemittel-Auslassbohrungen als Außenansicht,
• 2A: die stirnseitige Wand eines Scrollverdichter-Gehäuses mit drei Auslassbohrungen und einem Dreifingerventil, Stand der Technik,
• 2B: die stirnseitige Wand eines Scrollverdichter-Gehäuses mit drei Auslassbohrungen und einem Zweifingerventil,
• 3: eine schematische Darstellung der ineinander verschachtelten Spiralen eines Scrollverdichters,
• 4A: eine schematische Darstellung der ineinander verschachtelten Spiralen eines Scrollverdichters bei einem Rotationswinkel der Kurbelwelle von 0° /360°,
• 4B: eine schematische Darstellung der ineinander verschachtelten Spiralen eines Scrollverdichters bei einem Rotationswinkel der Kurbelwelle von 90°,
• 4C: eine schematische Darstellung der ineinander verschachtelten Spiralen eines Scrollverdichters bei einem Rotationswinkel der Kurbelwelle von 180°,
• 4D: eine schematische Darstellung der ineinander verschachtelten Spiralen eines Scrollverdichters bei einem Rotationswinkel der Kurbelwelle von 270°,
• 5: eine grafische Darstellung des isentropen Drucks des Kältemittels in Abhängigkeit vom Rotationswinkel der Kurbelwelle bei der isentropen Verdichtung im Kältemittel-Scrollverdichter im Klimaanlagenmodus,
• 6: eine grafische Darstellung des isentropen Drucks des Kältemittels in Abhängigkeit vom Rotationswinkel der Kurbelwelle bei der isentropen Verdichtung im Scrollverdichter im Wärmepumpenmodus.

Further details, features and advantages of embodiments of the invention will become apparent from the following description of exemplary embodiments with reference to the accompanying drawings. Show it:

• 1A : a section of a scroll compressor with the stationary scroll and refrigerant outlet holes in the spiral frontal wall of the scroll compressor housing as an interior view,
• 1B : the front wall of the scroll compressor housing with the refrigerant outlet holes as an external view,
• 2A : the frontal wall of a Scrollverdichter housing with three outlet holes and a three-finger valve, prior art,
• 2 B : the front wall of a scroll compressor housing with three outlet holes and a two-finger valve,
• 3 : a schematic representation of the nested spirals of a scroll compressor,
• 4A : a schematic representation of the nested spirals of a scroll compressor at a rotation angle of the crankshaft of 0 ° / 360 °,
• 4B : a schematic representation of the nested spirals of a scroll compressor with a rotation angle of the crankshaft of 90 °,
• 4C FIG. 2: a schematic representation of the nested spirals of a scroll compressor with a rotation angle of the crankshaft of 180 °, FIG.
• 4D : a schematic representation of the nested spirals of a scroll compressor with a rotation angle of the crankshaft of 270 °,
• 5 FIG. 2: a graphical representation of the isentropic pressure of the refrigerant as a function of the angle of rotation of the crankshaft during the isentropic compression in the refrigerant scroll compressor in air conditioning mode, FIG.
• 6 : A graphical representation of the isentropic pressure of the refrigerant as a function of the angle of rotation of the crankshaft in the isentropic compression in the scroll compressor in heat pump mode.

The 1A shows a section of a scroll compressor 1 with a part of the scroll compressor housing 2 on which a stationary spiral 3 is attached, as an interior view. This part is a stationary spiral frontal wall 2a the scroll compressor housing 2 , The stationary spiral 3 has a total winding angle of 660 °. Scroll compressors with a wrapping angle in the range of 440 ° to 900 ° require two outlets 4.1 ; 4.2 and a main outlet 5 to work efficiently. According to 1A There are two presets 4.1 ; 4.2 in the form of pre-drilled holes 4.1 ; 4.2 in the to the stationary spiral 3 frontal wall 2a the Scrollverdichtergehäuses 2 , Furthermore, there is a main outlet 5 in the form of a main outlet hole 5 also in the stationary spiral 3 frontal wall 2a of compressor housing 2 in the center of the stationary spiral 3 at the inner end region 3a , A first pilot hole 4.1 is in front of the inside of the spiral 3 positioned so that the pilot hole 4.1 the main outlet hole 5 from the stationary spiral 3 are enclosed without a wall of the stationary spiral 3 between the first pilot hole 4.1 and the main outlet hole 5 is placed. The second pilot hole 4.2 is in front of the outside of the stationary spiral 3 positioned so that the wall of the stationary spiral 3 between the main outlet hole 5 and the second pilot hole 4.2 is placed.

The 1B shows an external view of the scroll compressor 1 with a view of the frontal wall 2a the scroll compressor housing 2 with the pilot holes 4.1 ; 4.2 as well as the main outlet hole 5 , Here is the main outlet hole 5 essentially in the middle between the two pilot holes 4.1 ; 4.2 placed, with the main outlet hole 5 and the pilot hole 4.1 ; 4.1 are arranged substantially linearly.

The 2A shows the front wall of a Scrollverdichter housing with three outlet holes and a three-finger valve, as is known in the prior art. Thus all outlets can be closed after the pressure in the compression chamber drops below the high pressure area. This is to prevent that hot gas flows back into the compression chamber and the compressor loses its effectiveness.

The 2 B shows an exterior view of a scroll compressor 1 similar to in 1B , with a view of the spiral to the frontal wall 2a the scroll compressor housing 2 with the pilot holes 4.1 ; 4.2 as well as the main outlet hole 5 , Here is the main outlet hole 5 essentially in the middle between the two pilot holes 4.1 ; 4.2 placed, with the main outlet hole 5 and the pilot hole 4.1 ; 4.1 are arranged substantially linearly. As a valve for opening and closing the two pilot holes 4.1 ; 4.2 is a U-shaped or V-shaped valve 6 provided, with its U or V-legs 6.1 ; 6.2 the pre-drilling holes 4.1 ; 4.2 can be closed at the same time, while the main outlet hole 5 open in the free space between the U- or V-legs 6.1 . 6.2 located. This valve can also be referred to as a two-finger valve analogous to the three-finger valve.

• ➢eine nach außen geöffnete/öffenbare Verdichtungskammer als Saugdruckkammer 8 für das Ansaugen von Kältemittel, die in eine innere Ansaugkammer 8.1 und eine äußere Ansaugkammer 8.2, je nach Position der jeweiligen Ansaugkammer 8.1, 8.2 bezüglich der beweglichen Spirale, aufgeteilt ist,
• ➢eine mit der Saugdruckkammer 8 verbundene mittlere Verdichtungskammer 9, wobei je nach Position zur beweglichen Spirale immer eine innere mittlere Verdichtungskammer 9.1 und eine äußere mittlere Verdichtungskammer 9.2 vorliegt,
• ➢eine Kältemittelaustrittskammer 10, die mit der mittleren Verdichtungskammer 9 verbunden ist und in der sich die beiden inneren Endbereiche 3a; 7a der Spiralen 3; 7 gegenüberliegen.

The 3 schematically shows a cross section of the scroll compressor 1 with the stationary spiral 3 and a movable spiral 7 that are nested inside each other. Both spirals each have a total wrap angle of 660 ° with a total wrap angle of the spirals. The moving spiral 7 is eccentrically movable on a circular path, causing the volume of several different, between the spirals 3 ; 7 trained compression chambers 8th . 9 . 10 changes cyclically. Because the total wrap angle is 660 °, three different types of compression chambers are always formed. Like from the 3 recognizable, the following compression chambers are formed:

• ➢a compression chamber open to the outside / openable as a suction pressure chamber 8th for sucking refrigerant into an inner suction chamber 8.1 and an outer suction chamber 8.2 , depending on the position of the respective suction chamber 8.1 . 8.2 with respect to the movable spiral, is divided
• ➢one with the suction pressure chamber 8th connected middle compression chamber 9 , Wherein, depending on the position of the movable spiral always an inner middle compression chamber 9.1 and an outer medium compression chamber 9.2 is present,
• ➢a refrigerant outlet chamber 10 that with the middle compression chamber 9 is connected and in which the two inner end portions 3a ; 7a the spirals 3 ; 7 are opposite.

The 3 schematically shows two refrigerant outlets 4.1 ; 4.2 in the to the spirals 3 ; 7 frontal wall of the compressor housing. These two refrigerant outlets 4.1 ; 4.2 are closed by one or more Vorlassventile. Furthermore, as also in the 3 shown a refrigerant main outlet 5 in the to the spirals 3 ; 7 end wall of the compressor housing in the center of the stationary spiral 3 which is always open and has no valve.

Due to the special properties of the refrigerant (CO _2), the necessary high-pressure in all air-conditioning test points within the intermediate compression chambers 9.1 . 9.2 achieved at 360 ° rotation angle.

The spiral geometry, which is partly due to the winding angle of the spirals 3 ; 7 of 660 ° results in that the achievable dead volume is at a volume which is ≤ 9%, preferably ≤ 5%, of the intake volume or displacement. The 3 shows this position of the maximum compression of the refrigerant discharge chamber 10 in the center of the spirals 3 ; 7 ,

At values for the pressure ratio of ≤ 3.7 between the high pressure and the low pressure in the suction chambers 8.1 . 8.2 is present, has the missing valve at the main outlet 5 no negative Effect on the performance of the scroll compressor 1 , This applies to all air conditioning conditions.

At pressure ratios of> 3.7, the missing valve will lead to the main outlet 5 to a reflux of the refrigerant in the compression chamber. Such pressure conditions are present under heat pump conditions.

The figures 4A to 4D show schematic representations of the nested spirals 3 ; 7 a refrigerant scroll compressor 1 in air conditioning mode at different angles of rotation of the crankshaft, with which the moving spiral 7 is coupled. For the air conditioning mode is the maximum pressure ratio of 3.7 between the high pressure in the refrigerant discharge chamber 10 and the low pressure in the suction chambers 8.1 . 8.2 in front.

The 4A shows a schematic representation of the nested spirals 3 ; 7 a refrigerant scroll compressor 1 at a rotation angle of the crankshaft of 0 ° or 360 °. It is in the intake chambers 8.1 . 8.2 the internal pressure 35 bar. The internal pressure is in both the middle compression chambers 9.1 . 9.2 as well as in the refrigerant outlet chamber 10 each 130 bar. That is, the necessary high pressure is already in the middle compression chambers at a rotation angle of 360 ° - under all test conditions of the air conditioner 9.1 . 9.2 reached. Therefore, the main outlet 5 stay open and a valve is not necessary. Only the two refrigerant outlets 4.1 and 4.2 be opened or closed by means of Vorlassventilen.

In the 4B are nested spirals 3 ; 7 of the refrigerant scroll compressor 1 shown schematically at a rotation angle of the crankshaft of 90 °. The internal pressure of the suction chambers 8.1 . 8.2 is 35 bar. The internal pressure of the middle compression chambers 9.1 . 9.2 is 45 bar. The pressure in the refrigerant outlet chamber 10 is 130 bar.

The 4C shows a schematic representation of the nested spirals 3 ; 7 of the scroll compressor 1 at a rotation angle 180 ° of the crankshaft of 180 °. In this case, the internal pressure of the suction chambers 8.1 . 8.2 unchanged at 35 bar, the internal pressure of the middle compression chambers 9.1 . 9.2 rises to 57 bar. The pressure in the refrigerant outlet chamber 10 is - also unchanged - at 130 bar.

The 4D contains a schematic representation of the nested spirals 3 ; 7 at a rotation angle of the crankshaft of 270 °. The internal pressure of the suction chambers 8.1 . 8.2 is 35 bar. The internal pressure of the middle compression chambers 9.1 . 9.2 has risen to 79 bar. The pressure in the refrigerant outlet chamber (DC) is still 130 bar.

As from the related to the figures 4A to 4D high pressure is reached under air conditioning conditions, even before the refrigerant through the main outlet or main outlet 5 can escape. Therefore, no valve is required at the refrigerant main outlet.

The 5 shows one of the figures 4A to 4D corresponding graphical representation of the isentropic pressure of the refrigerant as a function of the angle of rotation of the crankshaft in the isentropic compression in the refrigerant scroll compressor in air conditioning mode. The pressure of the suctioned refrigerant is in the low pressure range (LP) at 35 bar. The refrigerant is compressed and reaches the area of the pilot holes. The pressure of the refrigerant increases exponentially simultaneously with the rotation of the crankshaft and finally reaches high pressure level (HP), with which the refrigerant then also reaches the area of the main outlet bore.

Only the pilot holes are equipped with blow-off valves that open and close the valves. Although there is no main exhaust valve, no backflow of the refrigerant into the combined internal compression chamber of the scroll compressor from the high pressure region occurs because the compression chamber and the cavity are at the same pressure level behind the refrigerant main outlet. The refrigerant scroll compressor has low outlet temperatures in air conditioning mode.

The 6 shows a graphical representation of the isentropic pressure of the refrigerant as a function of the angle of rotation of the crankshaft in the isentropic compression in the scroll compressor in heat pump mode.

The pressure of the sucked refrigerant is initially in the low pressure range at 20 bar and thus much lower compared to the air conditioning mode. The refrigerant is compressed, initially entering the area of the pilot holes. The pressure of the refrigerant increases exponentially with the rotation of the crankshaft, but is still well below the high pressure level (HP) when it reaches the area of the refrigerant outlet bore. Therefore, the refrigerant flows back from the high-pressure side into the combined inner compression chamber because the main outlet is always open and the compression chamber has a lower pressure level than the cavity behind the refrigerant outlet. The backflow of the refrigerant into the inner combined compression chamber is in 6 indicated schematically by means of vertical arrows. The backflow of hot refrigerant gas is advantageous for the heat pump mode, in which high outlet temperatures of the scroll compressor are sought.

LIST OF REFERENCE NUMBERS

1

Refrigerant scroll compressors

2

compressor housing

2a

front wall of the compressor housing

3

stationary spiral

3a

inner end region of the stationary spiral

4.1

Refrigerant delivery, pilot hole

4.2

Refrigerant delivery, pilot hole

5

Main refrigerant outlet, main outlet hole

6

Valve, pre-discharge valve

6.1

first leg of a U-shaped or V-shaped valve 6

6.2

second leg of a U- or V-shaped valve 6

7

movable spiral

7a

inner end region of the movable spiral

8th

Suction pressure chamber, compression chamber

8.1

inner suction chamber

8.2

outer suction chamber

9

middle compression chamber

9.1

inner middle compression chamber

9.2

outer middle compression chamber

10

Refrigerant outlet chamber, compression chamber

Claims (8)

Refrigerant scroll compressor (1) for use within a heat pump with CO ₂ as refrigerant, comprising • a compressor housing (2), • two spirals (3; 7) nested within the compressor housing (2), one of which (3) is stationary and the other scroll (7) is eccentrically movable in a circular path, whereby the volume of a plurality of different compression chambers (8, 9, 10) formed between the scrolls (3; 7) changes cyclically, the individual scrolls (3 7) each have a total winding angle in the range of 440 ° to 900 ° and between the spirals (3; 7) the following compression chambers (8, 9, 10) are formed: ➢a compression chamber as a suction pressure chamber (8) for the suction of refrigerant, which is divided into an inner suction chamber (8.1) and an outer suction chamber (8.2), ➢a central compression chamber (9), in an inner central compression chamber (9.1) and ei ne outer middle compression chamber (9.2) is divided, ➢eine refrigerant discharge chamber (10), in which the two inner end portions (3a; 7a) of the spirals (3; 7) are opposite each other, • two or more refrigerant outlets (4.1; 4.2) in a wall (2a) of the compressor housing (2) facing the spirals (3; 7), • one or more valves ( 6) for the opening and closing of the two refrigerant outlets (4.1; 4.2) and • a main refrigerant outlet (5) in the wall (2a) of the compressor housing (2) in the center of the stationary housing (2) facing the spirals (3; Spiral (3), which is always open and has no valve. Refrigerant Scroll Compressor (1) after Claim 1 Characterized in that the individual coils (3; 7) each have a total wrap angle in the range of 580 ° to 700 °. Refrigerant Scroll Compressor (1) after Claim 2 , characterized in that the individual spirals (3; 7) each have a total winding angle of 660 °. Refrigerant scroll compressor (1) according to one of Claims 1 to 3 , characterized in that the spirals (3; 7) are formed in terms of their spiral geometry such that they allow a reduction of the volume of the refrigerant discharge chamber to a dead space volume which is ≤ 9% of the suction volume of the scroll compressor (1). Refrigerant Scroll Compressor (1) after Claim 4 , characterized in that the spirals are formed in terms of their spiral geometry such that they allow a reduction in the volume of the refrigerant discharge chamber to a dead space volume, which is ≤ 5% of the intake volume of the scroll compressor (1). Refrigerant scroll compressor (1) according to one of Claims 1 to 5 , characterized in that a U-shaped or V-shaped valve (6) is provided as a valve for opening and closing the two refrigerant outlets (4.1, 4.2), with whose U or V legs (6.1, 6.2) the refrigerant outlets ( 4.1; 4.2) can be closed while the opened refrigerant main outlet (5) is positioned between the U- or V-legs (6.1, 6.2). Use of a refrigerant Scroll compressor (1) according to one of Claims 1 to 6 in a refrigerant circuit with CO ₂ as refrigerant, which is operable in the air conditioning mode and / or in the heat pump mode. Use after Claim 7 , characterized in that the refrigerant circuit is operated in heat pump mode, wherein the refrigerant outlets (4.1, 4.2) remain predominantly closed.

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