DE102017124814A1 - An air conditioning system for conditioning the air of a passenger compartment of a motor vehicle and method for operating the air conditioning system - Google Patents

Abstract

The invention relates to an air conditioning system (1a, 1b) for conditioning the air of a passenger compartment of a motor vehicle with a refrigerant circuit (2a, 2b) and an air conditioner (20). The refrigerant circuit (2a, 2b) has a compressor (4), a first refrigerant-air heat exchanger (5) for heat transfer between the refrigerant and ambient air, an expansion element (7) and a second refrigerant-air heat exchanger (8) for conditioning the supply air for the passenger compartment. The refrigerant circuit (2a, 2b) is also formed with a flow path (10) extending from a branch point (12) to an outlet point (13) with a heat exchanger (11). The branch point (12) is at an outlet of the compressor (4) and the discharge point (13) is arranged between the first refrigerant-air heat exchanger (5) and the expansion element (7). The air conditioner (20) has a housing for conducting and distributing the supply air for the passenger compartment with a first flow channel (21), in which the second refrigerant-air heat exchanger (8) is arranged, and a second flow channel (22), which as a bypass to the second refrigerant-air heat exchanger (8) is formed on. The air conditioner (20) is also formed with a flow guide (29) for closing and opening the first flow channel (21). The invention also relates to a method for operating the air conditioning system.

Description

The invention relates to an air conditioning system for conditioning the air of a passenger compartment of a motor vehicle with a refrigerant circuit and an air conditioner. The refrigerant circuit has a compressor, a first refrigerant-air heat exchanger for heat transfer between the refrigerant and ambient air, an expansion element and a second refrigerant-air heat exchanger for conditioning the supply air for the passenger compartment and a flow path with an additional heat exchanger. The air conditioner has a housing for conducting and distributing the supply air for the passenger compartment with a first flow channel for receiving the second refrigerant-air heat exchanger and a second flow channel formed as a bypass of the second refrigerant-air heat exchanger.

Furthermore, the invention relates to a method for operating the air conditioning system.

In known from the prior art motor vehicles, the waste heat of the engine is used to heat the supply air for the passenger compartment. The waste heat is transported to the air conditioner by means of the coolant circulated in the engine coolant circuit and transmitted there via the heater heat exchanger to the air flowing into the passenger compartment. Known systems with coolant-air heat exchanger, which relate the heating power from the coolant circuit of an efficient internal combustion engine of the vehicle drive, do not generate enough waste heat to heat in particular at low ambient temperatures, the air of the passenger compartment according to the requirements of thermal comfort or that for a comfortable heating reach the required level of the passenger compartment and cover the overall heat demand of the passenger compartment. The same applies to systems in motor vehicles with hybrid drive, that is motor vehicles with both electric motor and internal combustion engine drive.

If the total heat demand of the passenger compartment can not be covered by the heat from the engine coolant circuit, additional heating measures, such as electrical resistance heaters, briefly referred to as PTC resistor for "Positive Temperature Coefficient - Thermistor" or fuel heater, are required. The same applies to systems in purely electric motor driven vehicles or fuel cell vehicles. A more efficient way to heat the air for the passenger compartment is an air conditioning system with a refrigerant circuit with heat pump function, also referred to as a heat pump, with air as the heat source, in which the refrigerant circuit serves both as a single heating and Zuheizmaßnahme.

An air conditioning system with downstream electrical resistance heating is to produce a cost-effective and is to use in any motor vehicles, but has a very large demand for electrical energy, since the supply air for the passenger compartment when overflowing an evaporator of the refrigerant circuit initially cooled and / or dehumidified and then is heated by the electrical resistance heating, which transfers the heat directly to the supply air or a coolant circuit.

From the JP 2016 107979 A shows an air conditioning system for a motor vehicle with a refrigerant circuit and a coolant circuit for controlling the temperature of a drive motor. The coolant circuit also has a heating heat exchanger for conditioning the supply air for the passenger compartment. The refrigerant cycle is formed with a compressor, an evaporator-operable refrigerant-refrigerant heat exchanger for transferring heat from the refrigerant to the refrigerant, a condenser-operable refrigerant-refrigerant heat exchanger for transferring heat from the refrigerant to the refrigerant, and an expansion member. The refrigerant circuit also has a refrigerant-air heat exchanger operable as an evaporator for transferring heat from the supply air for the passenger compartment to the refrigerant. The refrigerant-air heat exchanger and the heat exchanger are arranged within an air conditioner.

Prior art air conditioning systems, which are designed for the combined refrigeration system mode and reheat mode, also referred to as reheat mode, receive the heat from the supply air for the passenger compartment. In this case, the refrigerant is evaporated by absorbing heat from the supply air, which is transmitted for example in a refrigerant-air heat exchanger directly to the refrigerant. The supply air for the passenger compartment thus serves as a heat source for the evaporation of the refrigerant. The refrigerant-air heat exchanger is arranged inside an air conditioner, in particular for conditioning, conducting and distributing the air.

In the so-called "reheat" or post-heating mode, the air to be supplied to the passenger compartment is cooled, dehumidified and then at least slightly reheated. In this operating mode, the required reheating power is usually less than the required cooling capacity for cooling and dehumidifying the air.

Especially with a cold start of the motor vehicle, it is possible, even at very low temperatures of the ambient air to heat the supply air by the operation of the refrigerant circuit in a so-called triangular process, also called hot gas mode. In this case, essentially only three components of the refrigerant circuit are supplied with refrigerant to the compressor, a heat exchanger for heating the supply air for the passenger compartment as a condenser / gas cooler and an expansion element. 1 shows the state changes of the refrigerant during operation of the refrigerant circuit in the triangular process in a logarithmic pressure (p) - enthalpy (h) - diagram. With the recirculation of the refrigerant in the refrigerant cycle compressor, the pressure level of the refrigerant is increased A, and the refrigerant absorbs the heat generated in the compressor. When flowing through the following in the flow direction of the compressor arranged as a condenser / gas cooler heat exchanger, the heat at a high pressure level to a coolant of a coolant circuit and then in a coolant-air heat exchanger from the coolant to the supply air for the passenger compartment or directly to the supply air for the Transfer passenger compartment B. The refrigerant-air-heat exchanger is, as the operated as an evaporator refrigerant-air heat exchanger disposed within an air conditioner.

After exiting the condenser / gas cooler, the refrigerant is expanded in the expansion device to a low pressure level C and sucked by the compressor.

With the operation of the refrigerant circuit in the triangular process or in the hot gas mode, the supply air of the passenger compartment can be heated with a similar efficiency as with an electrical resistance heater, but without relying on additional components.

If the refrigerant is liquefied with subcritical operation of the refrigerant circuit, such as with the refrigerant R134a or under certain environmental conditions with carbon dioxide, the heat exchanger is referred to as a capacitor. Part of the heat transfer takes place at a constant temperature. In supercritical operation or supercritical heat in the heat exchanger, the temperature of the refrigerant steadily decreases. In this case, the heat exchanger is also referred to as a gas cooler. Supercritical operation may occur under certain environmental conditions or operations of the refrigerant cycle with, for example, the refrigerant carbon dioxide.

In the known from the prior art operating modes of a refrigerant circuit in a triangular process is applied to the low pressure side, either no heat exchanger or operated as an evaporator for the refrigerant refrigerant air heat exchanger for conditioning the supply air for the passenger compartment with refrigerant, so that the suction side either no defined Temperature level is specified or the temperature level of the evaporator acting on the supply air, such as the ambient air is defined, which determines the suction pressure of the present in the two-phase region refrigerant.

If, on the one hand during the operation of the refrigerant circuit in the triangular process on the low pressure side no temperature level and thus no pressure level is specified or if on the other hand, the temperature level and thus the pressure level of the refrigerant by the temperature of the supply air for the passenger compartment, especially the ambient air at low temperature is determined , the suction pressure p _s decreases in each case in particular during the cold start of the motor vehicle 1 very high, which increases the risk of damage to the compressor, for example due to liquid shocks. For this reason, the power of the compressor is to be limited, but this leads to a reduced overall performance of the air conditioning system. In addition, very low temperatures of the ambient air, for example - 20 ° C and less, lead to such a reduction of the suction pressure p _s , that the compressor does not work due to a planned Saugdruckbegrenzung, for example, at R134a with 1.34 bar and a Saugdruckbegrenzung of about 1 bar.

In addition, conventional air conditioners are designed such that the operated as an evaporator refrigerant-air heat exchanger can not be shut off on the air side. The evaporator of the refrigerant is therefore always supplied with air. Air conditioners known from the prior art merely offer the possibility of passing a partial air mass flow through a so-called bypass on the evaporator.

Furthermore, refrigerant circuits of air conditioning systems are known in which the evaporator can be shut off on the refrigerant side. The refrigerant circuits in this case have a bypass formed around the evaporator flow path, through which the entire mass flow of the refrigerant is conductive. However, with the bypass and associated peripherals, such as valves and refrigerant lines, the refrigerant circuit has additional components, particularly to ensure operation in the hot gas mode. The additional components require additional space and cause additional costs, especially in the production and installation.

The object of the invention is now to provide an air conditioning system for a motor vehicle, which can be operated efficiently both in the refrigeration system mode, in the heat pump mode, especially in Nachheizmodus, as well as in the hot gas mode. The air conditioning system, in particular the refrigerant circuit, should be constructed structurally simple with a minimum necessary number of components, for example without Zuheizmaßnahmen to cause only minimal operating costs, manufacturing costs and maintenance costs and have a minimal space requirement. The refrigerant circuit should also be designed such that during the cold start of the motor vehicle with maximum power, especially when operating in hot gas mode, especially to heat the supply air for the passenger compartment efficiently.

The object is achieved by the subject matter and the method having the features of the independent claims. Further developments are specified in the dependent claims.

The object is achieved by an inventive air conditioning system for conditioning the air of a passenger compartment of a motor vehicle with a refrigerant circuit and an air conditioner.

The refrigerant circuit has a compressor, a first refrigerant-air heat exchanger for heat transfer between the refrigerant and ambient air, an expansion element and a second refrigerant-air heat exchanger for conditioning the supply air for the passenger compartment. The refrigerant circuit also has a flow path which extends from a branch point formed at an outlet of the compressor to a discharge point formed between the first refrigerant-air heat exchanger and the expansion element. Within the flow path another heat exchanger is arranged.

The air conditioner has a housing for conducting and distributing the supply air for the passenger compartment with a first flow channel and a second flow channel. Within the first flow channel, the second refrigerant-air heat exchanger of the refrigerant circuit is arranged. The second flow passage is formed as a bypass around the second refrigerant-air heat exchanger.

According to the concept of the invention, the air conditioner on a flow guide for closing and opening of the first flow channel, so that the second refrigerant-air heat exchanger of the refrigerant circuit for conditioning the supply air for the passenger compartment on the air side is completely shut off.

The cross-sectional area of the first flow channel of the air conditioning unit is preferably completely covered by the first refrigerant-air heat exchanger of the refrigerant circuit in order to avoid disturbing flows.

According to a development of the invention, the flow-guiding device is arranged in the flow direction of the supply air for the passenger compartment in front of the second refrigerant-air heat exchanger. The flow-guiding device is advantageously designed as an air flap. The flow guide is also preferably continuously adjustable between two end positions "fully open" and "fully closed".

According to a first alternative embodiment of the invention, the heat exchanger arranged within the branching point formed at the outlet of the compressor up to the flow path of the refrigerant circuit extending between the first refrigerant-air heat exchanger and the expansion element is used as a refrigerant-air heat exchanger for heating the supply air formed. The heat exchanger is arranged within the air conditioner in the flow direction of the supply air to the second refrigerant-air heat exchanger, in particular after an exit of the first flow channel.

According to a second alternative embodiment of the invention, the heat exchanger arranged within the branching point formed at the outlet of the compressor up to the flow path of the refrigerant circuit extending between the first refrigerant-air heat exchanger and the expansion element is a refrigerant-coolant heat exchanger of a coolant circuit educated. In this case, the coolant circuit also has a coolant-air heat exchanger, which is arranged within the air-conditioning unit for the passenger compartment with air to flow through. The coolant-air heat exchanger of the coolant circuit is arranged within the air conditioner in the flow direction of the supply air to the second refrigerant-air heat exchanger of the refrigerant circuit, in particular after the exit of the first flow channel.

The heat exchanger arranged within the flow path is advantageously parallel to the first refrigerant-air heat exchanger for heat transfer between the refrigerant and ambient air or instead of the first refrigerant-air heat exchanger. Heat exchanger flowed through by refrigerant. According to a first alternative embodiment of the invention, the branch point of the flow path of the refrigerant circuit is formed as a three-way valve.

According to a second alternative embodiment of the invention, the branch point of the flow path of the refrigerant circuit is formed as a valve arrangement with a T-piece, a first valve and a second valve. In this case, the first valve is disposed upstream of the first refrigerant-air heat exchanger in the flow direction of the refrigerant, in particular between the T-piece and the refrigerant-air heat exchanger. The second valve is arranged upstream of the flow path, in particular the heat exchanger formed inside the flow path.

According to a development of the invention, an accumulator is provided as a refrigerant reservoir within the refrigerant circuit in the flow direction of the refrigerant upstream of the compressor. In addition or alternatively, downstream of the first refrigerant-air heat exchanger downstream of a collector may be formed in the flow direction of the refrigerant. Likewise, a design of the refrigerant circuit without collector and accumulator is possible.

An advantage of the invention is that the air conditioner has a flow guide for closing and opening the second flow channel formed as a bypass around the second refrigerant-air heat exchanger. The flow guide of the second flow channel is advantageously designed as an air flap and is also preferably continuously adjustable between two end positions "fully open" and "fully closed".

The object of the invention is also achieved by a method according to the invention for operating an air conditioning system of a motor vehicle having a refrigerant circuit and an air conditioner for operation in a refrigeration system mode, in a heat pump mode, in particular in a reheating mode, and in a hot gas mode for the supply air to be conditioned of the passenger compartment ,

The refrigeration system mode is mainly used for cooling, the heat pump mode and the hot gas mode, the heating and Nachheizmodus the cooling and / or dehumidifying and reheating the supply air of the passenger compartment.

• - Leiten eines aus einem Verdichter ausströmenden Kältemittels auf einem Hochdruckniveau durch einen Strömungspfad und einen als Kondensator/Gaskühler betriebenen Wärmeübertrager, wobei Wärme vom Kältemittel abgegeben wird,
• - Leiten des aus dem Wärmeübertrager austretenden Kältemittels durch ein Expansionsorgan, wobei das Kältemittel auf ein Niederdruckniveau entspannt wird,
• - Leiten des aus dem Expansionsorgan austretenden Kältemittels durch einen in einem ersten Strömungskanal des Klimagerätes angeordneten Kältemittel-Luft-Wärmeübertrager und
• - Ansaugen des Kältemittels durch den Verdichter.

The method for operating the air conditioning system has the following steps during operation of the refrigerant circuit in the hot gas mode for heating the supply air of the passenger compartment:

• - Passing a refrigerant flowing out of a compressor at a high pressure level through a flow path and a heat exchanger operated as a condenser / gas cooler, wherein heat is released from the refrigerant,
• Passing the refrigerant exiting the heat exchanger through an expansion element, the refrigerant being expanded to a low pressure level,
• - Guiding the exiting the expansion element refrigerant by a arranged in a first flow channel of the air conditioner refrigerant-air heat exchanger and
• - Suction of the refrigerant by the compressor.

In this case, arranged in the flow direction of the supply air in the first flow channel in front of the refrigerant-air heat exchanger Strömungsleiteinrichtung is completely closed and the supply air is completely guided around an open second flow channel to the refrigerant-air heat exchanger, so that transmitted in the refrigerant-air heat exchanger heat Is zero.

According to a first alternative embodiment of the invention is in the condenser / gas cooler operated and designed as a refrigerant-air heat exchanger heat exchanger, which is arranged inside the air conditioner for conducting and distributing the supply air for the passenger compartment, heat transferred from the refrigerant to the supply air of the passenger compartment ,

According to a second alternative embodiment of the invention, in the condenser / gas cooler operated and designed as a refrigerant-refrigerant heat exchanger heat transfer heat from the refrigerant to a coolant of a coolant circuit. The heat absorbed by the coolant is then transferred from the coolant to the supply air of the passenger compartment in a coolant-air heat exchanger, which is arranged inside the air conditioner for conducting and distributing the supply air for the passenger compartment.

The air conditioning system according to the invention offers the possibility of heating the supply air of the passenger compartment via operation of the refrigerant circuit in a triangular process, in which the second refrigerant-air heat exchanger operated during operation in other modes as an evaporator can be completely shut off on the air side, so that the refrigerant air Heat exchanger is not acted upon or overflowed with air. By the air-side shut-off of the refrigerant-air heat exchanger, the suction pressure of the refrigerant circuit during operation in the triangular process not dependent on the temperature of the otherwise the refrigerant-air heat exchanger overflowing air, in particular the ambient air. Consequently, the suction pressure level of the refrigerant circuit can be raised, resulting in an increase in the heat output for heating the supply air for the passenger compartment and the risk of damaging the compressor due to low suction pressures can be reduced.

• - Klimatisieren, insbesondere Kühlen, Entfeuchten und/oder Heizen der Zuluft des Fahrgastraums mit minimalem Energieeinsatz,
• - Bereitstellen eines ausreichenden Komforts innerhalb des Fahrgastraums, insbesondere beim Betrieb im Heißgasmodus bei geringen Temperaturen der Umgebungsluft, durch Steigerung der Heizleistung und damit Aufheizen der Luft in sehr kurzer Zeit,
• - erhöhte Lebensdauer, da auch eine Schädigung des Verdichters durch einen zu geringen Saugdruck vermieden wird,
• - Kältemittelkreislauf, welcher zum Einsatz in bekannten Schemata und vorhandenen Bauräumen bestehender Kraftfahrzeuge integrierbar ist, sowie
• - minimale Anzahl von Komponenten im Kältemittelkreislauf, dadurch minimaler Bauraum, minimale Herstellungskosten und Wartungskosten auch durch Verzicht auf zusätzliche Komponenten im Klimatisierungssystem, wie elektrische Widerstandsheizungen.

The air conditioning system according to the invention for conditioning the air of a passenger compartment of motor vehicles has in summary various advantages:

• Air conditioning, in particular cooling, dehumidifying and / or heating the supply air of the passenger compartment with minimum energy input,
• Providing sufficient comfort within the passenger compartment, in particular when operating in the hot gas mode at low ambient air temperatures, by increasing the heating power and thus heating the air in a very short time,
• - Increased life, as well as damage to the compressor is avoided by a too low suction pressure,
• - Refrigerant circuit, which can be integrated for use in known schemes and existing space existing vehicles, as well as
• - Minimal number of components in the refrigerant circuit, thereby minimal space, minimum manufacturing costs and maintenance costs also by eliminating additional components in the air conditioning system, such as electrical resistance heaters.

• 2: ein Klimagerät mit dem zweiten Kältemittel-Luft-Wärmeübertrager des Kältemittelkreislaufs und einem Heizwärmeübertrager des Kühlmittelkreislaufs aus dem Stand der Technik sowie
• 3a und 3b: ein erfindungsgemäßes Klimagerät mit dem zweiten Kältemittel-Luft-Wärmeübertrager des Kältemittelkreislaufs und dem Heizwärmeübertrager des Kühlmittelkreislaufs mit alternativen Ausführungsformen des Kältemittelkreislaufs.

Further details, features and advantages of embodiments of the invention will become apparent from the following description of embodiments with reference to the accompanying drawings, in which air conditioning systems each having an air conditioner, a refrigerant circuit and a refrigerant circuit, comprising a compressor, a first and a second refrigerant. Air heat exchanger and an expansion element are shown. Show it

• 2 an air conditioner with the second refrigerant-air heat exchanger of the refrigerant circuit and a heating heat exchanger of the refrigerant circuit of the prior art and
• 3a and 3b : An inventive air conditioner with the second refrigerant-air heat exchanger of the refrigerant circuit and the heat exchanger of the refrigerant circuit with alternative embodiments of the refrigerant circuit.

Out 2 goes an air conditioning system 1' with a refrigerant circuit 2 ' and a coolant circuit 3 and an air conditioner 20 ' from the prior art.

The refrigerant circuit 2 ' has a compressor 4 , a first, in particular as Kondendsator / gas cooler operable refrigerant-air heat exchanger 5 for heat transfer between the refrigerant and ambient air with a collector 6 for separating and collecting refrigerant liquid, an expansion organ 7 and a second, in particular operable as an evaporator refrigerant-air heat exchanger 8th for conditioning the supply air for the passenger compartment. The collector 6 is on the high pressure side after the first refrigerant-air heat exchanger 5 and thus between the refrigerant-air heat exchanger 5 and the expansion organ 7 arranged.

The refrigerant circuit 2 ' is also with an accumulator 9 formed for the separation and collection of refrigerant liquid, which in the flow direction of the refrigerant in front of the compressor 4 and thus low-pressure side between the second refrigerant-air heat exchanger 8th and the compressor 4 is arranged. The compressor 4 sucks gaseous refrigerant from the accumulator 9 on. The refrigerant circuit 2 ' can alternatively either with the high pressure side arranged collector 6 or the low pressure side arranged accumulator 9 be educated.

The refrigerant circuit 2 ' has a first flow path 10 on, which starting from a branch point 12 up to an estuarine site 13 extends. The branch point 12 is in the flow direction of the refrigerant at or after exiting the compressor 4 arranged. The estuary 13 of the first flow path 10 is between the first refrigerant-air heat exchanger 5 and the expansion organ 7 , especially between the collector 6 and the expansion organ 7 , educated. Within the first flow path 10 is a particular designed as a refrigerant-refrigerant heat exchanger heat exchanger 11 for transferring heat from the refrigerant to a coolant of the coolant circuit 3 arranged. The branch point 12 is as a three-way valve 14 , in particular as a 3/2-way shut-off valve, designed so that the refrigerant as needed by the first refrigerant-air heat exchanger 5 for transferring heat from the refrigerant to ambient air and / or through the first flow path 10 with the refrigerant Coolant heat exchanger 11 for transferring heat from the refrigerant to the coolant into partial mass flows can be divided. The mass flow of the refrigerant can be between 0 and 100% on the heat exchanger 5 . 11 to be shared. The partial mass flows of the refrigerant are at the discharge point 13 mixed again.

The refrigerant circuit 2 ' is also with a second flow path 15 formed, which starting from a branch point 16 up to an estuarine site 17 extends. The branch point 16 is between the expansion organ 7 and the second refrigerant-air heat exchanger 8th arranged and advantageous as a three-way valve 16 , in particular as a 3/2-way shut-off valve formed. The estuary 17 of the second flow path 15 is between the second refrigerant-air heat exchanger 8th and the accumulator 9 arranged. The second flow path 15 Depending on your needs, it will be used as a bypass around the evaporator 8th operated, wherein the refrigerant at least in a partial mass flow around the evaporator 8th is divisible. The refrigerant can through the second refrigerant-air heat exchanger 8th for transferring heat from the supply air for the passenger compartment to the refrigerant and / or through the second flow path 15 be divided into sub-mass flows. The mass flow of the refrigerant can be divided between 0 and 100%. The partial mass flows of the refrigerant are at the discharge point 17 mixed again.

The coolant circuit 3 points next to the refrigerant-refrigerant heat exchanger 11 , which serves as a thermal connection to the refrigerant circuit 2 ' is formed, a coolant-air heat exchanger 18 for heating the supply air for the passenger compartment, hereinafter also as a heating heat exchanger 18 referred to. In addition, within the coolant circuit 3 a conveyor 19 , in particular a pump, for conveying the coolant through the coolant circuit 3 intended.

The air conditioner 20 ' of the air conditioning system 1' for conditioning, guiding and distributing the supply air for the passenger compartment has a housing with a first flow channel 21 on. Within the first flow channel 21 is operated as the evaporator for the refrigerant second refrigerant-air heat exchanger 8th arranged to transfer heat from the supply air to the refrigerant. The coolant-air heat exchanger 18 for heating the supply air is inside the housing of the air conditioner 20 ' in the flow direction 24 . 25 the supply air after the evaporator 8th for cooling and / or dehumidifying the supply air, in particular after the outlet of the first flow channel 21 arranged. The supply air is in the flow direction 26 initiated into the passenger compartment.

Because the first flow channel 21 with the refrigerant-air heat exchanger 8th inside the air conditioner 20 ' on the air side is not shut off, the heat exchanger 8th always with in the direction of flow 24 flowing air, in particular ambient air, against.

The air conditioner 20 ' also has a second flow channel 22 which acts as a bypass to the first flow channel 21 is designed to receive a partial air mass flow. One through the bypass 22 Guided first partial air mass flow is the air side of the evaporator 8th bypassed, wherein a second partial air mass flow through the first flow channel 21 to the evaporator 8th is directed. The trained as a bypass second flow channel 22 of the air conditioner 20 ' is by means of a particular designed as an air flap flow guide 23 completely lockable, so with the air damper open 23 a partial air mass flow through the bypass 22 and a partial air mass flow over the heat transfer surface of the evaporator 8th be directed. With closed air damper 23 and thus closed second flow channel 23 the total air mass flow through the first flow channel 21 and over the heat transfer surface of the evaporator 8th guided.

During operation of the refrigerant circuit 2 ' In the refrigeration system mode for cooling the supply air of the passenger compartment is in the evaporator 8th heat absorbed by the refrigerant and in the compressor 4 absorbed power when flowing through the condenser / gas cooler operated first refrigerant-air heat exchanger 5 to the ambient air and / or in the condenser / gas cooler operated refrigerant-coolant heat exchanger 11 to the coolant of the coolant circuit 3 transfer. In a coolant-air heat exchanger, not shown, the heat can then be released from the coolant to the ambient air or another heat sink. The heating heat exchanger 18 is not supplied with coolant or with supply air for the passenger compartment, so in the heating heat exchanger 18 no heat is transferred. The bypass 15 of the refrigerant circuit 2 ' is not charged with refrigerant.

During operation of the refrigerant circuit 2 ' in Nachheizmodus for cooling and / or dehumidifying and reheating the supply air of the passenger compartment is in the evaporator 8th heat absorbed by the refrigerant and in the compressor 4 absorbed power when flowing through the operated as a condenser / gas cooler refrigerant-coolant heat exchanger 11 to the coolant of the coolant circuit 3 transfer. The first refrigerant-air heat exchanger 5 does not flow through with refrigerant. The heat absorbed by the coolant is then in the heating heat exchanger 18 to the Supply air for the passenger compartment discharged, so that previously when overflowing the heat transfer surface of the evaporator 8th Cooled and / or dehumidified supply air when overflowing the heat transfer surface of Heizwärmeübertragers 18 is heated again.

The bypass 22 around the evaporator 8th can be open.

During operation of the refrigerant circuit 2 ' in the hot gas mode, in particular for rapidly heating the supply air of the passenger compartment at very low ambient air temperatures, the refrigerant in the compressor 4 from the low pressure level to the high pressure level A , according to 1 , Compresses, the refrigerant also absorbs heat. Subsequently, the refrigerant flows through the first flow path 10 for operated as a condenser / gas cooler refrigerant-refrigerant heat exchanger 11 , wherein in the refrigerant-refrigerant heat exchanger 11 at the high pressure level, heat from the refrigerant to the coolant of the coolant circuit 3 B. The heat is then transferred to the heat exchanger 18 discharged from the coolant to the supply air for the passenger compartment. The first refrigerant air heat exchanger 5 is not charged with refrigerant.

After exiting the first flow path 10 the refrigerant flows through the expansion element 7 and is relaxed to low pressure level and thus the suction pressure in the two-phase region of liquid and vapor C , The low pressure side from the heat exchanger 8th or from the bypass 15 escaping refrigerant is in the accumulator 9 passed and then in the gaseous state from the compressor 4 sucked. The refrigerant circuit 2 ' is closed.

The refrigerant circuit 2 ' is operated at very low temperatures of the ambient air in the hot gas mode to provide a high heating power and thus to heat the passenger compartment in a very short time to a comfortable temperature level.

When flowing through the refrigerant through the bypass 15 around the refrigerant-air heat exchanger 8th No heat exchanger is acted upon on the low-pressure side of the refrigerant, so that no defined temperature level is predetermined on the suction side, which determines the suction pressure of the refrigerant present in the two-phase region. However, if no temperature level and thus also no pressure level is predetermined on the low-pressure side, in particular during the cold start of the motor vehicle the suction pressure p _s decreases, according to FIG 1 , very strong.

When flowing through the refrigerant through the refrigerant-air heat exchanger 8th is the temperature level of the refrigerant from the heat exchanger 8th acting supply air, such as the ambient air defined, which also determines the suction pressure of the refrigerant present in the two-phase region. If the temperature level and thus the pressure level of the refrigerant is determined by the low temperature of the ambient air as supply air for the passenger compartment, also decreases, in particular during the cold start of the motor vehicle, the suction pressure p _s , according to 1 , very strong. For example, the risk of damaging the compressor due to the strong drop in suction pressure p _s 4 , especially by liquid shocks, increased. To counter this will be the performance of the compressor 4 limited, but also the overall performance of the air conditioning system 1' reduced.

In the 3a and 3b in each case an air conditioning system according to the invention 1a . 1b with a refrigerant circuit 2a . 2 B in alternative embodiments and a coolant circuit 3 and an air conditioner 20 shown.

The refrigerant circuit 2a . 2 B indicates how the refrigerant circuit 2 ' out 2 , a compressor 4 , a first refrigerant-air heat exchanger which can be operated, in particular, as a conditioner / gas cooler 5 for heat transfer between the refrigerant and ambient air with a collector 6 , an expansion organ 7 and a particular operable as an evaporator second refrigerant-air heat exchanger 8th for conditioning the supply air for the passenger compartment. The compressor 4 sucks gaseous refrigerant from the accumulator 9 on.

The refrigerant circuit 2a . 2 B again indicates a branch point 12 up to an estuarine site 13 extending flow path 10 on, being within the flow path 10 in particular designed as a refrigerant-coolant heat exchanger heat exchanger 11 for transferring heat from the refrigerant to the coolant of the coolant circuit 3 is arranged.

In the first embodiment of the air conditioning system 1a to 3a is the branch point 12 of the refrigerant circuit 2a as a three-way valve 14 , in particular as a 3/2-way shut-off valve formed.

In the first alternative second embodiment of the air conditioning system 1b to 3b is the branch point 12 of the refrigerant circuit 2 B from a tee in combination with a first valve 27 and a second valve 28 formed as a valve assembly. In this case, the first, in particular designed as a shut-off valve 27 in the flow direction of the refrigerant first refrigerant-air heat exchanger 5 preferably upstream and thus between the tee of the branch point 12 and the heat exchanger 5 arranged. The second, in particular designed as a shut-off valve 28 is inside the flow path 10 in the flow direction of the refrigerant to the refrigerant-refrigerant heat exchanger 11 advantageously upstream and thus between the tee of the branch point 12 and the heat exchanger 11 arranged.

With the training of the branch office 12 as a three-way valve 14 to 3a or as a valve assembly according to 3b The refrigerant can be supplied as needed by the first refrigerant-air heat exchanger 5 for transferring heat from the refrigerant to ambient air and / or through the flow path 10 with the refrigerant-refrigerant heat exchanger 11 for transferring heat from the refrigerant to the refrigerant in sub-mass flows are divided. The mass flow of the refrigerant is between 0 and 100% on the heat exchanger 5 . 11 divisible.

In contrast to the refrigerant circuit 2 ' out 2 indicates the refrigerant circuit 2a . 2 B from the 3a and 3b no refrigerant line formed as a bypass around the second refrigerant-air heat exchanger operated as an evaporator 8th on. This will make the refrigerant circuit 2a . 2 B even without a three-way valve as a branch point and as an inlet to the bypass and the flow path to the heat exchanger 8th educated. The at the confluence 13 from the partial mass flows mixed total mass flow of the refrigerant is completely through the heat exchanger 8th directed.

The coolant circuit 3 the embodiments of the air conditioning systems 1a . 1b according to the 3a and 3b corresponds in each case to the coolant circuit 3 of the air conditioning system 1' to 3 ,

The air conditioner 20 of the air conditioning system 1a . 1b for conditioning, guiding and distributing the supply air for the passenger compartment points within the first flow channel 21 the operated as an evaporator for the refrigerant second refrigerant-air heat exchanger 8th for cooling and / or dehumidifying the supply air and thus for transferring heat from the supply air to the refrigerant and in the flow direction 24 . 26 the supply air after the evaporator 8th , in particular after the exit of the first flow channel 21 , the coolant-air heat exchanger 18 for heating the supply air. After passing the heating heat exchanger 18 the supply air is in the flow direction 26 directed into the passenger compartment.

Compared to the air conditioner 20 ' of the air conditioning system 1' out 2 has the air conditioning system 1a . 1b the 3a and 3b in each case a flow-guiding device 29 on, which is designed as a flap in the flow direction 24 the air in front of the heat exchanger 8th , in particular within the first flow channel 21 , is arranged. With the in the flow of the heat exchanger 8th arranged air damper 29 is the first flow channel 21 completely closable and thus the refrigerant-air heat exchanger 8th completely shut off on the air side. The first flow channel 21 in which the heat exchanger 8th is arranged, by means of the air damper 29 fully open or fully closed. The air damper 29 is infinitely adjustable between the end positions "fully open" and "fully closed".

As the air conditioner 20 also a second flow channel 22 which acts as a bypass for conducting an air mass flow around the heat exchanger 8th is formed around, the whole through the air conditioner 20 directed mass air flow through the bypass 22 and thus on the heat exchanger 8th over and to the heating heat exchanger 18 be guided. The second refrigerant-air heat exchanger 8th is then not charged with air, especially with supply air.

Also within the second flow channel 22 is a formed in particular as an air damper flow guide 23 provided, with which the second flow channel 22 completely open or completely closed.

For the operating modes of the refrigerant circuit 2a . 2 B in the cooling system mode for cooling the supply air of the passenger compartment and in Nachheizmodus for cooling and / or dehumidifying and reheating the supply air of the passenger compartment is to the comments too 2 directed.

During operation of the refrigerant circuit 2a . 2 B in the hot gas mode, in particular for rapidly heating the supply air of the passenger compartment at very low ambient air temperatures, the refrigerant in the compressor 4 from the low pressure level to the high pressure level A , according to 1 , condensed. The refrigerant also absorbs heat. Subsequently, the refrigerant passes through the flow path 10 and operated as a condenser / gas cooler refrigerant-refrigerant heat exchanger 11 conducted, being in the refrigerant-refrigerant heat exchanger 11 at the high pressure level, heat from the refrigerant to the coolant of the coolant circuit 3 B. The transferred to the coolant heat is subsequently in the heat exchanger 18 transferred from the coolant to the supply air for the passenger compartment. The first refrigerant air heat exchanger 5 is not flowed through by the refrigerant.

After exiting the flow path 10 the refrigerant flows through the expansion element 7 and is at low pressure level and thus the suction pressure in the two-phase region of liquid and steam relaxed C. That at the low pressure level from the expansion organ 7 escaping refrigerant is completely through the heat exchanger 8th in the accumulator 9 passed and then in the gaseous state from the compressor 4 sucked. The refrigerant circuit 2a . 2 B , which is operated in particular at very low temperatures of the ambient air in the hot gas mode in order to provide a high heating power and thus to heat the passenger compartment in a very short time to a comfortable temperature level is closed.

During operation of the refrigerant circuit 2a . 2 B in hot gas mode are in the direction of flow 24 in front of the heat exchanger 8th arranged air damper 29 and thus the first flow channel 21 closed. The supply air is completely through the opened second flow channel 22 around the heat exchanger 8th led around. This is in the heat exchanger 8th no heat is transferred from the refrigerant to the supply air through the heat exchanger 8th Guided refrigerant is not cooled, which would lower the suction pressure of the refrigerant. The refrigerant points at the inlet and outlet of the heat exchanger 8th the same temperature level and thus the same pressure level. The at the heat exchanger 8th Passing supply air for the passenger compartment is transferred directly to the heating heat exchanger 18 guided and in the heating heat exchanger 18 heated.

The air-side shut-off of the heat exchanger 8th It also allows the suction pressure level of the refrigerant compared to the operation of the air conditioning system 1' to 2 to increase. This can also be achieved a higher high pressure level, which is off 1 with the different state progressions emerges. The arrow indicates the raising of the low pressure level. The course shown by the dotted line illustrates the process of the refrigerant without air-side shut-off of the heat exchanger 8th During the course shown with the dashed line, the process of the refrigerant with air-side shut-off of the heat exchanger 8th clarified.

During operation of the refrigerant circuit 2a . 2 B at higher pressure levels, especially at higher high pressure levels, a greater amount of heat is used to heat the refrigerant in the refrigerant-refrigerant heat exchanger 11 provided, so that a larger amount of heat for heating the supply air in the heating heat exchanger 18 is available and the supply air can be warmed up in a shorter time to a certain temperature.

With the operation of the air conditioning system 1a . 1b In the hot gas mode, it is possible in addition to stabilizing the Saugdruckniveaus and setting a certain low temperature levels and thus a defined suction pressure, even at very low ambient air temperatures during cold start of the motor vehicle to provide a sufficiently high power for heating the supply air for the passenger compartment and thus the requirements of thermal comfort without having to meet additional electrical resistance heating.

With the operation of the refrigerant cycle in the hot gas mode, the supply air of the passenger compartment can be heated with similar efficiency as with an electrical resistance heater, without, however, relying on additional components. At the same time, the risk of damaging the compressor due to low suction pressures is minimized.

The refrigerant circuit and the operating modes can be used for any refrigerant which passes through a phase transition from liquid to gaseous on the low pressure side. On the high pressure side, the medium releases the absorbed heat to a heat sink through gas cooling / condensation and subcooling. Suitable refrigerants are natural substances such as R744, R717 and similar combustible substances such as R290, R600, R600a and similar chemical substances such as R134a, R152a, HFO-1234yf, as well as various mixtures of refrigerants.

LIST OF REFERENCE NUMBERS

1 ', 1a, 1b

Cooling system

2 ', 2a, 2b

Refrigerant circulation

3

Coolant circuit

4

compressor

5

Heat exchanger, first refrigerant-air heat exchanger, condenser / gas cooler

6

collector

7

expansion element

8th

Heat exchanger, second refrigerant-air heat exchanger, evaporator

9

accumulator

10

(first) flow path

11

Heat exchanger, refrigerant-refrigerant heat exchanger

12

branching point

13

opening point

14

Three-way valve

15

second flow path, bypass

16

Branch point, three-way valve

17

opening point

18

Coolant-air heat exchanger, heating heat exchanger

19

Conveying device, pump

20 ', 20

air conditioning

21

first flow channel

22

second flow channel, bypass

23

Flow guiding device, air flap flow channel 22

24

Flow direction Supply air Flow evaporator 8th

25

Flow direction Supply air Flow Heating heat exchanger 18

26

Flow direction of incoming air passenger compartment

27

first valve, shut-off valve branch 12

28

second valve, shut-off valve branch 12

29

Flow guiding device, air flap Flow evaporator 8th

A, B, C

State change refrigerant

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• JP 2016107979 A [0006]

Claims (11)

An air conditioning system (1a, 1b) for conditioning the air of a passenger compartment of a motor vehicle having a refrigerant circuit (2a, 2b), comprising: - a compressor (4), a first refrigerant-air heat exchanger (5) for heat transfer between the refrigerant and ambient air, an expansion device (7) and a second refrigerant-air heat exchanger (8) for conditioning the supply air for the passenger compartment, - A flow path (10) extending from a branch point (12) to an outlet point (13) and formed with a heat exchanger (11), wherein the branch point (12) at an outlet of the compressor (4) and the discharge point (13) between the first refrigerant-air heat exchanger (5) and the expansion device (7) are formed, and an air conditioner (20), comprising a housing for conducting and distributing the supply air for the passenger compartment - A first flow channel (21) in which the second refrigerant-air heat exchanger (8) is arranged, and - A second flow channel (22) which is formed as a bypass around the second refrigerant-air heat exchanger (8), wherein the air conditioner (20) has a flow guide (29) for closing and opening the first flow channel (21). Air conditioning system (1a, 1b) according to Claim 1 , characterized in that the flow guide (29) in the flow direction (24) of the supply air for the passenger compartment in front of the second refrigerant-air heat exchanger (8) is arranged. Air conditioning system (1a, 1b) according to Claim 1 or 2 , characterized in that the flow-guiding device (29) is designed as an air flap. Air conditioning system (1a, 1b) according to one of Claims 1 to 3 , characterized in that the flow guide (29) between two end positions "fully open" and "fully closed" is continuously adjustable. Air conditioning system (1a, 1b) according to one of Claims 1 to 4 , characterized in that the heat exchanger (11) is designed as a refrigerant-air heat exchanger for heating the supply air and within the air conditioner (20) in the flow direction (24) of the supply air to the second refrigerant-air heat exchanger (8). Air conditioning system (1a, 1b) according to one of Claims 1 to 5 , characterized in that the heat exchanger (11) as a refrigerant-refrigerant heat exchanger (11) of a coolant circuit (3) is formed, wherein the coolant circuit (3) comprises a coolant-air heat exchanger (18) for heating the supply air, which inside the air conditioner (20) in the flow direction (24) of the supply air to the second refrigerant-air heat exchanger (8) is arranged. Air conditioning system (1a) according to one of Claims 1 to 6 , characterized in that the branching point (12) of the flow path (10) as a three-way valve (14) is formed. Air conditioning system (1b) according to one of Claims 1 to 6 characterized in that the branching point (12) of the flow path (10) is formed as a valve assembly having a T-piece, a first valve (27) and a second valve (28), wherein - the first valve (27) is the first Refrigerant-air heat exchanger (5) is arranged upstream in the flow direction of the refrigerant and - the second valve (28) within the flow path (10) is arranged. Method for operating an air conditioning system (1a, 1b) of a motor vehicle with a refrigerant circuit (2a, 2b) and an air conditioner (20) for operation in a refrigeration system mode, in a heat pump mode, in particular in a postheating mode, and in a hot gas mode for the to be conditioned Supply air of the passenger compartment according to one of Claims 2 to 8th in the operation of the hot gas mode for heating the supply air of the passenger compartment comprising the following steps: - passing a compressor (4) effluent refrigerant at a high pressure level through a flow path (10) and operated as a condenser / gas cooler heat exchanger (11), wherein heat discharging the refrigerant leaving the heat exchanger (11) by an expansion element (7), the refrigerant being expanded to a low pressure level, passing the refrigerant exiting the expansion element (7) through a refrigerant in a first flow channel ( 21) of the air conditioner (20) arranged refrigerant-air heat exchanger (8) and - suction of the refrigerant through the compressor (4), wherein in the flow direction (24) of the supply air in the first flow channel (21) in front of the refrigerant-air heat exchanger (8) arranged flow guide (29) is closed and the supply air through an open second flow channel (22) is guided around the refrigerant-air heat exchanger (8), so that in the refrigerant-air heat exchanger (8) transmitted heat is zero. Method for operating an air conditioning system (1a, 1b) of a motor vehicle Claim 9 with a refrigerant circuit (2a, 2b) according to one of Claims 2 to 5 and 7 and 8, characterized in that in the formed as a refrigerant-air heat exchanger heat exchanger (11) which is disposed within the air conditioner (20) for conducting and distributing the supply air for the passenger compartment, heat from the refrigerant to the supply air of the passenger compartment is transmitted. Method for operating an air conditioning system (1a, 1b) of a motor vehicle Claim 9 with a refrigerant circuit (2a, 2b) according to one of Claims 2 to 4 and 6 to 8th characterized in that in the formed as a refrigerant-refrigerant heat exchanger heat exchanger (11) heat from the refrigerant to a coolant of a coolant circuit (3) and in a coolant-air heat exchanger (18), which within the air conditioner (20) for conducting and distributing the supply air for the passenger compartment is arranged, heat is transferred from the coolant to the supply air of the passenger compartment.

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