DE102004041251A1 - Compressor used as a fixed displacement compressor for an air conditioning system for vehicles comprises a suction gas throttle - Google Patents

Abstract

Compressor comprises a suction gas throttle (1-6). An independent claim is also included for a process for operating the compressor. Preferred Features: Super-critically operating coolant gases, such as carbon dioxide, are used. The suction gas throttle regulates the power or limits the power of the compressor or air conditioning system. The suction gas throttle has a fixed or adjustable cross-section which can be externally controlled, preferably in a mechanical or electrical manner. The suction gas throttle has a pressure-sensitive component.

Description

The invention relates to a compressor for air conditioners or a compressor air conditioning system, in particular for motor vehicles, preferably for supercritically operated refrigerant gases, such as CO ₂ .

Such compressors or air conditioning systems are known. In this case, a power control in CO ₂ systems is realized via a variable capacity of the compressor. For air conditioners with subcritically operated refrigerants are also power control over a bypass and. a fluid buffer in the condenser in conjunction with a cycled via a switchable coupling compressor known.

However, these power regulations have certain disadvantages. Thus, the displacement control requires complex adjustment mechanisms. The power control via a bypass is energetically disadvantageous. In addition, no fluid buffer can be exploited, for example, when operated with the refrigerant CO ₂ plants, since in the gas cooler, the refrigerant CO ₂ can not always be liquefied (supercritical operation).

It is therefore an object of the invention, a compressor or air conditioning that does not have these disadvantages.

The object is achieved by a compressor for air conditioners or a compressor air conditioning system, in particular for motor vehicles, wherein the compressor or the air conditioning in Saugdruckbereich has a Sauggasdrosseleinrichtung and the compressor is a fixed-stroke compressor. According to the invention, the compressor or the air conditioning system can be used for supercritically operated refrigerant gases, such as CO ₂ . Preferably, the Sauggasdrosseleinrichtung is used for power control or power limitation of the fixed-lift air conditioning compressor or air conditioning.

One inventive compressor or an air conditioning system according to the invention is characterized in that the Sauggasdrosseleinrichtung a having fixed or adjustable throttle cross-section, wherein the adjustable throttle cross-section externally controlled, for example mechanically or electrically, or by other equally acting adjustment can be adjusted.

Prefers will continue a compressor or air conditioning, in which or wherein the Sauggasdrosseleinrichtung a pressure-sensitive component having. According to the invention can the pressure-sensitive component, for example, the outlet pressure PD or the pressure difference PD - P atmosphere or the suction pressure PS or the pressure difference PD - PS or a pressure difference be effective on a throttle.

Also a compressor or air conditioning is preferred in which or which the Sauggasdrosseleinrichtung a by an external signal actuated Actuating device such. B. an electromagnet, if necessary additionally to the pressure-sensitive component. Furthermore, a compressor or an air conditioner preferred, in which or which the external Signal by evaluating a pressure difference of a throttle body or the outlet pressure PD over a pressure sensor and / or the evaporator temperature or by a Setpoint change is generated, or by evaluating, for example, the suction pressure PS or the pressure difference PD - P atmosphere or PD - PS. Also, a compressor or an air conditioner is preferred in which or which the external signal by an electronic control device is generated and possibly be the electric current for an electromagnet can.

One inventive compressor or an air conditioning system according to the invention are characterized by the fact that the adjusting device infinitely adjustable or is controllable. Furthermore, by the adjusting device or Regulating the evaporator temperature stepless or sliding be adjustable or adjustable, for example between 1 ° Celsius and 12 ° Celsius. According to the invention can thereby the mass flow sliding or continuously to the power requirement the air conditioning or compressor (sliding Power control).

Preferably the compressor or the air conditioning system has a Sauggasdrosseleinrichtung, which by an electronic control device by means of an inter nal or external regulation, which z. B. pressures or temperatures as an input signal used, can be adjusted.

Preferably, the compressor or the air conditioning system has a Sauggasdrosseleinrichtung, which can be arranged in an assembly with evaporator and expansion valve or at the evaporator outlet or at the receiver outlet or in the suction line or in the inner heat exchanger suction or suction port (intake) of the compressor or in Kompressoransaugbereich (Sauglamellenbereich) , Furthermore, a compressor or an air-conditioning system in which the suction gas throttle device passes through is preferred a bottleneck in Saugkanalquerschnitt can be displayed. Also, a compressor or an air conditioner is preferred, in which / which the Sauggasdrosseleinrichtung is represented by reduced suction lamellae or a reduced inlet cross-section to the working space of the cylinder block.

A compressor according to the invention or an air conditioning system according to the invention is characterized in that a drop in the density of the refrigerant is generated by the pressure drop across the Sauggasdrosseleinrichtung, so that the mass flow can be reduced at a given volumetric flow rate of the air conditioning compressor. This has the advantage that the pressure peaks to be expected in CO ₂ plants, for example, can be avoided as a result of high uncontrolled mass flows on the pressure side. Also, the system of the invention has the advantage of being less expensive than engine displacement controlled and energetically cheaper to be bypass controls. Furthermore, it is advantageous that all today common types of compressors can be used with the invention.

The The invention will now be described with reference to the figures.

1 shows an air conditioner with possible throttle points.

2 shows a part of an air conditioning compressor with a narrowed suction channel.

3 shows an air compressor with narrowed inlet cross section to the working space.

4 shows a Saugdrosseleinrichtung with a pressure-sensitive component in a schematic representation.

5 shows a Sauggasdrosseleinrichtung with pressure-sensitive component and additional external setpoint specification.

6 shows a Sauggasdrosseleinrichtung without pressure-sensitive component, but with an external control.

In 1 the cycle of an air conditioner for the refrigerant CO _{2 is} shown. An air conditioning compressor 10 compresses the refrigerant to a high pressure, for example, 135 bar and pushes this refrigerant under high pressure in a line section 12 , which becomes a gas cooler 14 leads. In the gas cooler 14 the highly compressed refrigerant is cooled by a corresponding cooling air flow, for example from 180 ° C to 45 ° C, which is due to the cooling and the pressure losses in the gas cooler, the pressure of 135 bar in front of the gas cooler to a pressure of, for example, 133 bar behind the gas cooler in the line section 16 lowers. The pipe section 16 leads the high-pressure coolant to an internal heat exchanger 18 in which the high-pressure gas in the region by the counter-current of the low-pressure gas 20 the internal heat exchanger is cooled further. This decreases in the subsequent line section 22 the temperature of the refrigerant down to, for example, 30 ° C at a pressure of about 130 bar. In an expansion valve 24 Then, the high-pressure refrigerant is lowered to a low pressure of, for example, 35 bar, wherein the refrigerant to a temperature of about 1 to 2 ° C drops. The now under low pressure standing cold refrigerant in the line section 26 is through an evaporator 28 guided where it is reheated by a cooling air flow for the passenger compartment of the motor vehicle and thereby in the line section 30 with a temperature of about 3 ° C and a pressure of, for example, 33 bar to a receiver 32 arrives. The receiver is intended as a reservoir for the corresponding amounts of coolant. From the receiver 32 is over the line 34 the refrigerant in the low pressure side 20 passed to the internal heat exchanger, where it is heated by the heat exchange with the refrigerant of the high pressure side to about 30 ° C and then with a pressure of for example 35 bar in the line area 36 to the intake area 40 of the compressor 10 arrives.

For the arrangement of a Sauggasdrosseleinrichtung offer itself preferably in the low pressure region of the air conditioning, the following installation locations. The Sauggasdrosseleinrichtung can be integrated in the low pressure line, for example in the area 1 be arranged. This is a preferred installation site, since the cooling of the refrigerant by the Sauggasdrosselung even further, for example below 0 ° C, optionally to -10 ° C, and by the higher density and the temperature difference of the inner heat exchanger 18 can be made smaller. The pressure can drop to 15 bar. Furthermore, the Sauggasdrosseleinrichtung in the low pressure region 20 of the heat exchanger 18 So in the area 2 to be ordered. Another possibility is the arrangement of the Sauggasdrosseleinrichtung in an assembly with evaporator and expansion valve or at the output 3 of the receiver 32 , An arrangement of the Sauggasdrosseleinrichtung in the area is also conceivable 4 , ie in the low-pressure suction line 36 between the internal heat exchanger 18 and the intake area 40 of the compressor 10 , Furthermore, an arrangement of the Sauggasdrosseleinrichtung in the intake at the suction port 5 the compressor possible. Also possible is an arrangement the Sauggasdrosseleinrichtung within the compressor in the intake 6 ,

In 2 a compressor is shown, which should be designed as a fixed-stroke compressor and in which the cylinder head 52 can be seen in section. The compressor has a housing 50 on which by a cylinder head 52 is completed. The housing has, not shown here, a compressor engine, which z. B. by a pulley 54 is driven within a belt drive of an internal combustion engine. In the cylinder head itself are separated spaces and thus pressure areas for the intake 56 and for the ejection area 58 intended. In the intake area 56 It is now advantageous, a bottleneck in Saugkanalbereich 60 to install, so as to realize the Sauggasdrosseleinrichtung. In this case, the Sauggasdrosseleinrichtung in the area 60 cut both by a narrowed suction channel with a constant throttle cross-section as well as by a narrowed suction channel with adjustable Drosselquer, for example in the form of an electromagnetically controllable or electric motor adjustable throttle cross section, are shown. The throttle cross-section can also be realized by a mechanical adjusting device, which reacts, for example, to pressures or temperatures.

In 3 Another possibility for the arrangement of a Sauggasdrosseleinrichtung is shown. A cross section through a fixed lift air conditioning compressor shows a compressor housing 70 passing through a cylinder head 72 is completed. In the case 70 is a cylinder block 74 arranged, which within cylinder bores 76 reciprocating pistons 78 having. The pistons 78 are here for example via connecting rods 80 with receiving pans 82 a swash plate 84 connected. The swash plate device 84 is by means of a pulley 86 over a wave 88 rotated and thus generates the reciprocating motion of the pistons 78 , The pistons suck 78 from the intake area 90 the refrigerant on and push it in the area 92 via outlet openings 94 , which with exhaust valves 96 are provided, off. In the intake area 90 are in a valve plate 102 suction ports 98 attached, which by Ansauglamellenventile 100 can be opened and closed. In the area of these intake openings 98 or the suction lamellae 100 it is now possible, Sauggasdrosseleinrichtungen 104 , For example in the form of narrowed cross sections, which can be designed both as fixed suction throttles and as adjustable suction throttles to realize.

In 4 a Sauggasdrosseleinrichtung with a pressure-sensitive component is shown schematically. In a compressor housing part 110 is in an opening 112 a pressure-sensitive component 114 , here in the form of a schematic piston arranged. The piston 114 will be on the piston side 116 from the force of a schematically illustrated spring 118 applied. On the opposite side 120 of the piston 114 is another spring 122 in the opposite direction effective. Additionally is in the opening 112 a set screw 124 arranged, with which the biasing force of the spring 122 can be adjusted. The piston 114 sticks out with a part 126 out of the opening 112 into a canal 128 in, which is acted upon by the suction pressure PS, while blocking the part 126 of the piston 114 a part of the passage cross section of the channel 128 , That means the channel 128 for the suction pressure PS through the valve piston 114 is narrowed in the position shown here. On the other side of the piston 114 becomes the piston guide hole 112 from a channel 130 cut, which is acted as a channel for the discharged refrigerant with the outlet pressure PD of the compressor. Thus acting on the piston 114 , So on the pressure-sensitive component, on the one hand, the outlet pressure PD on the piston surface 116 and on the other hand, the suction pressure PS on the piston surface 120 , The higher pressure PD in the outlet channel 130 acts against the lower suction pressure PS in the channel 128 and against the biasing force of the spring 122 when the force of the spring 118 can be considered negligible. This is especially the case when this spring actually only for basic positioning of the piston 114 in the unpressurized state against the actual setting spring 122 is used. By the biasing force of the spring 122 can then by means of the adjustment 124 be determined at which pressure difference of outlet pressure PD and suction pressure PS of the intake passage 128 to be closed. According to the pressure changes occurring in operation in the outlet area as well as in the suction area of the piston 114 infinitely different positions can take.

In 5 is a throttle device with a comparable pressure-sensitive component 114 shown, but with the spring 122 and the set screw 124 by an electromagnetic actuator 131 are replaced. The electromagnet 131 consists in principle of a magnet armature 132 that's about a pushrod 138 with the piston 114 is connected and in the pressureless and possibly de-energized state by a spring 134 , which against the spring 118 acts, is brought into a desired basic position. The electromagnet basically also contains a coil 136 , which when excited, depending on the design of the magnet anchor 132 in the coil 136 can pull in or push out. In addition to the pressure influences on the pressure-sensitive component 114 , So the pressure difference between the outlet pressure in the channel 130 and the suction pressure in the intake passage 128 , via the electromagnet, the position of the throttling part 126 , So the throttle cross-section, remotely controlled and changed. The version shown here corresponds to a so-called set-point control, ie the controlled variable DP = PD - PS is measured directly at the valve. The magnetic force acts in addition to the controlled variable on the adjustment 114 ,

In 6 another throttle device is shown, but not to the outlet pressure PD in direct form on the valve element is effective. The piston 140 the throttle valve is here in a blind hole 142 housed, which has no connection to the outlet pressure channel 130 Has. On the piston 140 of the throttle valve so only the suction pressure in the channel acts 128 , A part of the piston 140 , the part 144 , protrudes into the suction channel 128 into it and thus again generates a throttle point. With the electromagnet 131 is the piston 140 over the pushrod 138 connected, and the other elements of the electromagnet 131 are identical to the description in the 5 , Unlike in 5 but the outlet pressure is detected by a pressure sensor and the pressure signal 146 in a control device 148 , in principle in the form of an electronic control introduced. Another input for the control device 148 For example, the signal 150 the evaporator temperature in order to realize a corresponding sliding evaporator temperature control. Other or other input signals from the air conditioning circuit are conceivable depending on the desired control strategy. The control device 148 in turn generates an output signal 152 , For example, in the form of a magnetic current, with which the electromagnet 131 is pressed. In this case, both pulse width modulated currents and currents for a proportional valve use, ie for the use of a proportional solenoid, as an output of the climate control 148 be generated. At the here in 6 illustrated control is clearly shown an evaporator temperature control, which can be realized in this way, even with a fixed-stroke compressor in a simple manner. In this embodiment, the Sauggasdrosseleinrichtung the controlled variable, so the outlet pressure PD, processed externally. On the adjusting element 140 can also act only the magnetic force, if one eliminates the influence of the suction pressure by diverting to both piston surfaces.

All Sauggasdrosseleinrichtungen proposed here has in common that can be designed as a fixed or adjustable throttle to limit the mass flow at high speeds of the fixed-lift air conditioning compressor of the intake. This causes a pressure drop and thus a density drop of the refrigerant. The compressor sucks during the intake phase in the working cylinder. Due to the reduced density, the mass flow is reduced in accordance with the equation of state for a given volumetric delivery rate (volume flow), and the torque of the compressor also reduces and leads to energy savings. Also, the compressor is much more cooled, which has a positive effect on lubrication and wear reduction. The invention avoids the pressure peaks otherwise to be expected in the case of CO ₂ plants, which would occur as a result of high uncontrolled mass flows and due to the absence of a liquid buffer on the pressure side. It can be used for the invention all today conventional compressor designs. The advantage according to the invention is also reflected in more favorable energy balances than in the bypass arrangements used today. The invention can preferably be applied to automotive air conditioning systems which are operated with CO ₂ . In general, however, the invention is valuable for all refrigerant gases which are operated in an air conditioning supercritical, ie with non-liquefied phases. Compared with displacement-controlled machines with adjustable swashplates or swash plates, the invention with a Fixhubmaschine and a Sauggasdrosseleinrichtung is cheaper. Thus, the invention is especially advantageous for so-called low-cost air conditioning systems.

1-6

installation locations Sauggasdrosseleinrichtung

10

air compressor

12

line section

14

gas cooler

16

line section

18

High pressure side internal heat exchanger

20

Low pressure side internal heat exchanger

22

line section

24

expansion valve

26

line section

28

Evaporator

30

line section

32

receiver

34

line section

36

management area

40

suction compressor

50

Housing compressor

52

cylinder head compressor

54

pulley

56

suction

58

discharge area

60

Saugkanalbereich

70

compressor housing

72

cylinder head

74

cylinder block

76

cylinder bores

78

piston

80

pleuel

82

Recording Kugelpfannen

84

swash plate

86

pulley

88

wave

90

suction

92

outlet

94

outlet

96

exhaust

98

suction ports

100

Ansauglamellenventile

102

valve plate

104

Sauggasdrosseleinrichtungen

110

Compressor housing part

112

opening

114

piston

116

piston side

118

feather

120

other side piston

122

feather

124

screw

126

piston part

128

suction pressure

130

discharge pressure passage

131

electromagnet

132

armature

134

feather

136

Kitchen sink

138

pushrod

140

piston

142

blind hole

144

piston part

146

pressure signal

148

control device

150

Evaporator temperature signal

152

output control device

Claims (19)

Compressor for air conditioning or air conditioning with compressor, especially for motor vehicles, characterized in that the compressor or the air conditioning in Saugdruckbereich has a Sauggasdrosseleinrichtung and the compressor is a fixed-stroke compressor. Compressor or air conditioning system according to claim 1, characterized in that supercritically operated refrigerant gases, such as CO ₂ , can be used. Compressor or air conditioning system according to claim 1 or 2, characterized in that the Sauggasdrosseleinrichtung for Power control or power limitation of the fixed-stroke compressor or the air conditioning is used. Compressor or air conditioning system according to claim 1 to claim 3, characterized in that the Sauggasdrosseleinrichtung a fixed or adjustable throttle cross-section, wherein the adjustable Throttle cross section controlled externally, for example mechanically or electrically, can be adjusted. Compressor or air conditioning system according to claim 4, characterized characterized in that the Sauggasdrosseleinrichtung a pressure-sensitive Component has. Compressor or air conditioning system according to claim 5, characterized characterized in that the pressure-sensitive component, for example the outlet pressure PD or the pressure difference PD - P atmosphere or the suction pressure PS or the pressure difference PD - PS or a pressure difference, which is generated at a throttle, can be effective. Compressor or air conditioning system according to claim 4 to 6, characterized in that the Sauggasdrosseleinrichtung a operable by an external signal Actuating device, such as an electromagnet, if necessary in addition to the pressure-sensitive component Compressor or air conditioning system according to claim 7, characterized characterized in that the external signal by evaluation of the pressure difference at a throttle device and / or the outlet pressure by means of a Pressure sensor and / or the evaporator temperature and / or by a Setpoint change is generated, possibly also by evaluation of the pressure signals Claim 6. Compressor or air conditioning system according to claim 7 or Claim 8, characterized in that the external signal by an electronic Regeleinrrrung is generated and possibly the power for one Electromagnet can be. Compressor or air conditioning system according to claim 7 to 9, characterized in that the adjusting device continuously adjustable or is controllable. Compressor or air conditioning system according to claim 10, characterized characterized in that by the adjusting device or control device the evaporator temperature infinitely or slidably adjustable or adjustable is, for example, between 1 ° Celsius and 12 ° Celsius. Compressor or air conditioning system according to claim 10 or 11, characterized in that thereby the mass flow sliding or continuously adapted to the power requirement of the air conditioning can be (sliding power control). Compressor or air conditioning system according to claim 4 to 12, characterized in that the Sauggasdrosseleinrichtung by an electronic control device by means of an internal or external control can be adjusted. Compressor or air conditioning system according to one of the preceding claims, characterized records that the Sauggasdrosseleinrichtung can be arranged in an assembly with evaporator and expansion valve or at the evaporator outlet or at the receiver outlet or in the suction line or in the heat exchanger inner suction or suction port (intake) of the compressor or in Kompressoransaugbereich (Sauglamellenbereich). Compressor or air conditioning after one of the previous ones Claims, characterized in that the Sauggasdrosseleinrichtung by a Bottleneck in Saugkanalquerschnitt can be displayed. Compressor or air conditioning after one of the previous ones Claims, characterized in that the Sauggasdrosseleinrichtung by downsized Suction lamella or by a reduced inlet cross section to Working space of the cylinder block can be displayed. Compressor or air conditioning after one of the previous ones Claims, characterized in that by the pressure drop across the Sauggasdrosseleinrichtung a density drop of the refrigerant is generated, so that at a given volumetric flow rate the compressor of the mass flow can be reduced. Compressor or air conditioning after one of the previous ones Claims, characterized in that by the Sauggasdrosseleinrichtung pressure peaks can be avoided on the pressure side. Method for operating a device according to claim 1 to 18.