WO2005022053A1

WO2005022053A1 - Compressor or air-conditioning system

Info

Publication number: WO2005022053A1
Application number: PCT/DE2004/001883
Authority: WO
Inventors: Willi Parsch; Tilo SCHÄFER
Original assignee: Luk Fahrzeug-Hydraulik Gmbh & Co. Kg
Priority date: 2003-09-02
Filing date: 2004-08-26
Publication date: 2005-03-10
Also published as: DE112004002149D2; DE102004041251A1

Abstract

The invention relates to a compressor (10) for use in an air-conditioning system or to an air-conditioning system comprising such a compressor (10), especially for motor vehicles. The invention is characterized in that the compressor or the air-conditioning system, in the suction pressure area (1, 2, 3, 4, 5, 6), comprises a suction gas throttle and the compressor (10) is a fixed displacement compressor.

Description

Compressor or air conditioning

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

Such compressors or air conditioning systems are known. Power control in CO ₂ systems is implemented via a variable displacement of the compressor. In air conditioning systems with subcritically operated refrigerants, power controls via a bypass and a liquid buffer in the condenser in conjunction with a compressor cycled via a switchable clutch are also known.

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

It is therefore an object of the invention to present a compressor or an air conditioning system which does not have these disadvantages.

The object is achieved by a compressor for air conditioning systems or an air conditioning system with a compressor, in particular for motor vehicles, the compressor or the air conditioning system having a suction gas throttle device in the suction pressure region and the compressor being 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 . The suction gas throttle device is preferably used to regulate or limit the capacity of the fixed-stroke air conditioning compressor or the air conditioning system.

A compressor according to the invention or an air conditioning system according to the invention is characterized in that the suction gas throttle device has a fixed or adjustable one Throttle cross-section, wherein the adjustable throttle cross-section can be controlled externally, for example mechanically or electrically, or by other adjusting devices having the same effect.

Also preferred is a compressor or an air conditioning system in which or in which the suction gas throttle device has a pressure-sensitive component. According to the invention, 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 at a throttle can act on the pressure-sensitive component.

A compressor or air conditioning system is also preferred, in which the suction gas throttle device has an actuating device that can be actuated by an external signal, such as, for. B. an electromagnet, possibly in addition to the pressure-sensitive component. Furthermore, a compressor or air conditioning system is preferred, in which the external signal is generated by evaluating a pressure difference of a throttle element or the outlet pressure PD via a pressure sensor and / or the evaporator temperature or by changing the setpoint value, or by evaluating, for example, the suction pressure PS or the Pressure difference PD - P atmosphere or PD - PS. A compressor or air conditioning system is also preferred, in which the external signal is generated by an electronic control device and the electrical current for an electromagnet may be.

A compressor according to the invention or an air conditioning system according to the invention are characterized in that the actuating device is infinitely adjustable or controllable. Furthermore, the evaporator temperature can be continuously or slidably adjustable or controllable, for example between 1 ° Celsius and 12 ° Celsius, by means of the adjusting device or control device. According to the invention, the mass flow can thereby be smoothly or continuously adapted to the power requirement of the air conditioning system or the compressor (sliding power control).

The compressor or the air conditioning system preferably has a suction gas throttle device which is controlled by an electronic control device by means of an internal NEN or external regulation, which z. B. pressures or temperatures used as input signal can be adjusted.

The compressor or the air conditioning system preferably has a suction gas throttle device which is arranged in a module with an 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 area or on the suction connection (intake tract) of the compressor or in the compressor intake area (suction lamella area) can be. Also preferred is a compressor or an air conditioning system in which the suction gas throttle device can be represented by a constriction in the suction channel cross section. A compressor or air conditioning system is also preferred, in which the suction gas throttle device can be 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 the pressure drop at the suction gas throttle device produces a density drop in the refrigerant, so that the mass flow can be reduced for a given volumetric delivery rate of the air conditioning compressor. This has the advantage that the pressure peaks to be expected in CO ₂ systems, for example, as a result of high unregulated mass flows on the pressure side, can be avoided. The system according to the invention also has the advantage of being less expensive than displacement-controlled machines and of being more energy-efficient than bypass controls. It is also advantageous that all types of compressors customary today can be used with the invention.

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

Figure 1 shows an air conditioning system with possible throttling points.

Figure 2 shows part of an air conditioning compressor with a narrowed suction channel. Figure 3 shows an air conditioning compressor with a narrowed inlet cross-section to the work area.

Figure 4 shows a suction throttle device with a pressure-sensitive component in a schematic representation.

FIG. 5 shows a suction gas throttle device with a pressure-sensitive component and an additional external setpoint.

Figure 6 shows a suction gas throttle device without a pressure-sensitive component, but with an external control.

In Figure 1, the circuit of an air conditioning system for the refrigerant CO _{2 is} shown. An air conditioning compressor 10 compresses the refrigerant to a high pressure of, for example, 135 bar and pushes this refrigerant under high pressure into a line section 12, which leads to a gas cooler 14. 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, with the cooling and pressure losses in the gas cooler causing the pressure from 135 bar upstream of the gas cooler to a pressure of, for example, 133 bar behind the gas cooler in line section 16. The line section 16 leads the high-pressure coolant to an internal heat exchanger 18, in which the high-pressure gas is further cooled by the counterflow of the low-pressure gas in the region 20 of the internal heat exchanger. As a result, the temperature of the refrigerant in the subsequent line section 22 drops to, for example, 30 ° C. at a pressure of approximately 130 bar. In an expansion valve 24, the high-pressure refrigerant is then lowered to a low pressure of, for example, 35 bar, the refrigerant dropping to a temperature of approximately 1 to 2 ° C. The cold refrigerant in the line section 26, which is now under low pressure, is passed through an evaporator 28, where it is reheated by an air stream to be cooled for the passenger compartment of the motor vehicle and thereby in the line section 30 with a temperature of approximately 3 ° C. and a pressure of for example 33 bar reaches a receiver 32. The receiver is intended as an expansion tank for the corresponding coolant quantities. From the receiver 32 the refrigerant is passed via line 34 into the low-pressure side 20 of the internal heat exchanger, where it is heated to about 30 ° C. by the heat exchange with the refrigerant on the high-pressure side and then with a pressure of, for example, 35 bar in the line area 36 to the suction area 40 of the Compressor 10 arrives.

For the arrangement of a suction gas throttle device, the following installation locations are preferred in the low-pressure area of the air conditioning system. The suction gas throttle device can be integrated in the low-pressure line, for example in area 1. This is a preferred installation location because the refrigerant cools even further through the suction gas throttling, for example below 0 ° C., possibly down to -10 ° C., and the inner heat exchanger 18 can be made smaller due to the higher density and the temperature difference. The pressure can drop to 15 bar. Furthermore, the suction gas throttle device can be arranged in the low pressure region 20 of the heat exchanger 18, that is to say in region 2. Another possibility is the arrangement of the suction gas throttle device in a module with evaporator and expansion valve or at the outlet 3 of the receiver 32. An arrangement of the suction gas throttle device in the area 4, ie. H. in the low-pressure suction line 36 between the internal heat exchanger 18 and the suction area 40 of the compressor 10. Furthermore, an arrangement of the suction gas throttle device in the suction area at the suction connection 5 of the compressor is possible. An arrangement of the suction gas throttle device within the compressor in the suction area 6 is also possible.

FIG. 2 shows a compressor which is to 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 which is closed off by a cylinder head 52. The housing has, not shown here, a compressor engine, which, for. B. is driven by a pulley 54 within a belt drive of an internal combustion engine. Separate spaces and thus pressure areas for the intake area 56 and for the exhaust area 58 are provided in the cylinder head itself. In the suction area 56, it is now advantageous to provide a constriction in the suction channel area 60 in order to implement the suction gas throttle device. In this case, the suction gas throttle device in the region 60 can be both through a narrowed suction channel with a constant throttle cross section and through a narrowed suction channel with an adjustable throttle cross section. section, for example in the form of an electromagnetically controllable or electromotively controllable throttle cross section. The throttle cross section can also be realized by a mechanical adjusting device which reacts, for example, to pressures or temperatures.

FIG. 3 shows another possibility for arranging a suction gas throttle device. A cross section through a fixed-stroke air conditioning compressor shows a compressor housing 70, which is closed off by a cylinder head 72. A cylinder block 74 is arranged in the housing 70 and has pistons 78 that can move back and forth within cylinder bores 76. The pistons 78 are connected here, for example via connecting rods 80, to receiving ball sockets 82 of a swash plate 84. The swashplate device 84 is rotated by means of a belt pulley 86 via a shaft 88 and thus generates the reciprocating movement of the pistons 78. The pistons 78 suck in the refrigerant from the suction area 90 and push it in the area 92 via outlet openings 94, which are provided with outlet valves 96. In the suction area 90, suction openings 98 are provided in a valve plate 102, which can be opened and closed by suction lamella valves 100. In the area of these suction openings 98 or the suction lamellae 100, it is now possible to implement suction gas throttle devices 104, for example in the form of narrowed cross sections, which can be designed both as fixed suction throttles and as adjustable suction throttles.

A suction gas throttle device with a pressure-sensitive component is shown schematically in FIG. A pressure-sensitive component 114, here in the form of a schematic piston, is arranged in an opening 112 in a compressor housing part 110. The piston 114 is acted upon on the piston side 116 by the force of a schematically illustrated spring 118. On the opposite side 120 of the piston 114, a further spring 122 is effective in the opposite direction. In addition, an adjusting screw 124 is arranged in the opening 112, with which the prestressing force of the spring 122 can be adjusted. The piston 114 protrudes with a part 126 from the opening 112 into a channel 128 which is subjected to the suction pressure PS, and the part 126 of the piston 114 blocks part of the passage cross section of the channel 128. This means that the channel 128 for the suction pressure PS through the valve piston 114 in the position shown here is narrowed. On the other side of the piston 114 the

Piston guide opening 112 cut by a channel 130, which is acted upon as a channel for the expelled refrigerant with the outlet pressure PD of the compressor. Thus, the outlet pressure PD on the piston surface 116 and the suction pressure PS on the piston surface 120 act on the piston 114, that is to say on the pressure-sensitive component. The higher pressure PD in the outlet duct 130 acts against the lower suction pressure PS in the duct 128 and against the biasing force of the spring 122 when the force of the spring 118 can be assumed to be negligible. This is particularly the case when this spring is actually only used for the basic positioning of the piston 114 in the depressurized state against the actual adjusting spring 122. The prestressing force of the spring 122 can then be used by means of the adjusting device 124 to determine at which pressure difference between the outlet pressure PD and the suction pressure PS the intake duct 128 is to be closed. Depending on the pressure changes occurring in operation in the outlet area as well as in the suction area, the piston 114 will be able to assume various positions in a stepless manner.

FIG. 5 shows a throttle device with a comparable pressure-sensitive component 114, but the spring 122 and the adjusting screw 124 are replaced by an electromagnetic adjusting device 131. The electromagnet 131 basically consists of a magnet armature 132 which is connected to the piston 114 via a push rod 138 and is brought into a desired basic position in the depressurized and possibly de-energized state by a spring 134 which acts against the spring 118. In principle, the electromagnet also contains a coil 136 which, when excited, depending on the design of the magnet, can pull the armature 132 into the coil 136 or push it out. In addition to the pressure influences on the pressure-sensitive component 114, i.e. the pressure difference between the outlet pressure in the channel 130 and the intake pressure in the intake channel 128, the position of the throttling part 126, i.e. the throttle cross-section, can be set and changed remotely via the electromagnet. 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. In addition to the controlled variable, the magnetic force acts on the adjusting element 114. A further throttle device is shown in FIG. 6, but the outlet pressure PD does not act directly on the valve element. The piston 140 of the throttle valve is accommodated here in a blind bore 142, which has no connection to the outlet pressure channel 130. Only the suction pressure in the channel 128 acts on the piston 140 of the throttle valve. A part of the piston 140, the part 144, projects into the suction channel 128 and thus again creates a throttle point. The piston 140 is connected to the electromagnet 131 via the push rod 138, and the other elements of the electromagnet 131 are identical to the description in FIG. 5. Unlike in FIG. 5, however, the outlet pressure is detected via a pressure sensor and the pressure signal 146 into a pressure sensor Control device 148, in principle in the form of an electronic control. A further input variable for the control device 148 can be the signal 150 of the evaporator temperature, for example, in order to implement a smooth evaporator temperature control accordingly. Depending on the desired control strategy, further or different input signals from the air conditioning circuit are conceivable. 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 actuated. Both pulse width modulated currents and currents for a proportional valve insert, ie for the use of a proportional magnet, can be generated as the output signal of the climate control 148. In the control system shown here in FIG. 6, an evaporator temperature control system is clearly shown, which in this way can also be implemented in a simple manner with a fixed stroke compressor. In this embodiment of the suction gas throttle device, the controlled variable, ie the outlet pressure PD, is processed externally. Only the magnetic force can act on the adjusting element 140 if the influence of the suction pressure is eliminated by redirection to both piston surfaces.

All suction gas throttle devices proposed here have in common that in order to limit the mass flows at high speeds of the fixed-stroke air conditioning compressor, the intake cross section can be designed as a fixed or adjustable throttle. This causes a drop in pressure and thus a decrease in the density of the refrigerant. The compressor sucks into the working cylinders during the suction phase. Due to the reduced density, the mass flow and the torque of the compressor are reduced in accordance with the state equation for a given volumetric flow rate (volume flow) reduces and leads to energy savings. The compressor is also cooled considerably more, which has a positive effect on lubrication and wear reduction. The invention avoids the pressure peaks that would otherwise be expected in CO ₂ systems, which would occur as a result of high unregulated mass flows and due to the lack of a liquid buffer on the pressure side. All types of compressor that are common today can be used for the invention. The advantage according to the invention is also reflected in cheaper energy balances than in the bypass controls used today. The invention can preferably be used in automotive air conditioning systems that are operated with CO ₂ . In general, however, the invention is valuable for all refrigerant gases which are operated supercritically in an air conditioning system, ie with non-liquefied phases. Compared to displacement-controlled machines with adjustable swivel plates or swash plates, the invention with a fixed lifting machine and a suction gas throttle device is more cost-effective. The invention is therefore particularly advantageous for so-called low-cost air conditioning systems.

LIST OF REFERENCE NUMERALS

Installation locations of suction gas throttle device

air compressor

line section

gas cooler

line section

High pressure side of internal heat exchanger

Low pressure side of internal heat exchanger

line section

expansion valve

line section

Evaporator

line section

receiver

line section

management area

Intake area compressor

Housing compressor

Cylinder head compressor

pulley

suction

discharge area

Saugkanalbereich

compressor housing

cylinder head

cylinder block

cylinder bores

piston

pleuel

Recording Kugelpfannen

swash plate

pulley 88 wave

90 suction area

92 outlet area

94 outlet openings

96 exhaust valves

98 suction openings

100 intake louvre valves

102 valve plate

104 suction gas throttling devices

110 compressor housing part

112 opening

114 pistons

116 piston side

118 spring

120 opposite piston

122 spring

124 set screw

126 piston part

128 suction pressure channel

130 outlet pressure channel

131 electromagnet

132 magnetic armature

134 spring

136 coil

138 push rod

140 pistons

142 blind hole

144 piston part

146 pressure signal

148 control device

150 evaporator temperature signal

152 Control device output signal

Claims

claims

1. Compressor for air conditioning or air conditioning with a compressor, in particular for motor vehicles, characterized in that the compressor or air conditioning has a suction gas throttle device in the suction pressure region and the compressor is a fixed stroke compressor.

2. Compressor or air conditioning system according to claim 1, characterized in that supercritically operated refrigerant gases, such as CO ₂ , can be used.

3. Compressor or air conditioning system according to claim 1 or 2, characterized in that the suction gas throttle device is used for power control or power limitation of the fixed stroke compressor or the air conditioning system.

Compressor or air conditioning system according to claim 1 to claim 3, characterized in that the suction gas throttle device has a fixed or adjustable throttle cross-section, the adjustable throttle cross-section being externally controlled, for example mechanically or electrically.

Compressor or air conditioning system according to claim 4, characterized in that the suction gas throttle device has a pressure-sensitive component.

6. Compressor or air conditioning system according to claim 5, characterized in that on 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.

7. Compressor or air conditioning system according to claim 4 to 6, characterized in that the suction gas throttle device has an actuating device which can be actuated by an external signal, such as an electromagnet, possibly in addition to the pressure-sensitive component

8. Compressor or air conditioning system according to claim 7, characterized in that the external signal is generated by evaluating 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, possibly also by evaluation of the pressure signals from claim 6.

9. Compressor or air conditioning system according to claim 7 or claim 8, characterized in that the external signal is generated by an electronic control device and, if appropriate, the current can be for an electromagnet.

10. compressor or air conditioning system according to claim 7 to 9, characterized in that the actuating device is infinitely adjustable or controllable.

11. Compressor or air conditioning system according to claim 10, characterized in that the evaporator temperature is infinitely or slidably adjustable or controllable by the adjusting device or control device, for example between 1 ° Celsius and 12 ° Celsius.

12. Compressor or air conditioning system according to claim 10 or 11, characterized in that the mass flow can be adjusted smoothly or continuously to the power requirement of the air conditioning system (sliding power control).

13. Compressor or air conditioning system according to claim 4 to 12, characterized in that the suction gas throttle device can be adjusted by means of an electronic control device by means of an internal or external control.

14. Compressor or air conditioning system according to one of the preceding claims, characterized in that the suction gas throttle device in a module with an 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 area or on the suction connection (intake tract) of the compressor or in Compressor suction area (suction lamella area) can be arranged.

15. Compressor or air conditioning system according to one of the preceding claims, characterized in that the suction gas throttle device can be represented by a constriction in the suction channel cross section.

16. Compressor or air conditioning system according to one of the preceding claims, characterized in that the suction gas throttle device can be represented by reduced suction lamellae or by a reduced inlet cross section to the working space of the cylinder block.

17. Compressor or air conditioning system according to one of the preceding claims, characterized in that a drop in density of the refrigerant is generated by the pressure drop at the suction gas throttle device, so that the mass flow can be reduced for a given volumetric delivery rate of the compressor.

18. Compressor or air conditioning system according to one of the preceding claims, characterized in that pressure peaks on the pressure side can be avoided by the suction gas throttle device.

19. A method of operating a device according to claim 1 to 18.