DE102017208296B4 - Method for limiting a refrigerant escaping from a refrigerant circuit of a vehicle air conditioning system, as well as a vehicle air conditioning system - Google Patents

Abstract

The invention relates to a method for limiting a refrigerant escaping from a refrigerant circuit (2) of a vehicle air conditioning system (1), the refrigerant circuit (2) being an assembly (2.0) comprising an indirect evaporator (2.2) with an associated expansion element (2.3) and an indirect refrigerant condenser (2.4), a refrigerant compressor (2.1), which on the low pressure side by means of a first valve element (2.5) arranged at the refrigerant outlet of the assembly (2.0) with the indirect evaporator (2.2) and on the high pressure side by means of a second valve element (2.6 ) is fluidly connectable, comprises a suction pressure side pressure-temperature sensor (2.7) and a high-pressure side pressure-temperature sensor (2.8). In order to ensure that in all operating states of the refrigerant circuit (2) there is as little refrigerant as possible in the refrigerant lines between the assembly (2.0) and the refrigerant compressor (2.1), both in the case of decommissioning, commissioning and in the case of refrigerant filling of the refrigerant circuit, the two valve elements (2.5) and (2.6) and the refrigerant compressor (2.1) controlled or operated in a certain way. The invention also relates to a vehicle air conditioning system for carrying out the method according to the invention.

Description

The invention relates to a method for limiting a refrigerant escaping from a refrigerant circuit of a vehicle air conditioning system in the event of a collision. The invention also relates to a vehicle air conditioning system with a refrigerant circuit for carrying out the method according to the invention.

Air conditioning systems are currently operated with the refrigerants R134a (Frigen) and R1234yf. In the future, however, it is planned to switch to R744 (carbon dioxide, CO2) as the refrigerant. Since high CO2 concentrations in the refrigerant can have harmful effects on health, uncontrolled leakage of the refrigerant into the passenger compartment, especially in the event of a vehicle crash (collision), must be prevented. Even with an arrangement of lines carrying refrigerant in the engine compartment, a vehicle crash can lead to refrigerant escaping into the engine compartment, so that it cannot be ruled out that refrigerant could get into the passenger compartment, for example via the fan of the ventilation or air conditioning system can.

the DE 10 2012 108 731 A1 describes a method for operating a refrigerant circuit of a vehicle air conditioning system for conditioning the supply air flow of a passenger compartment of the vehicle, the refrigerant circuit having a refrigerant compressor, a heat exchanger for heat transfer between the refrigerant and the environment and a heat exchanger for supplying heat from refrigerant to the supply air flow to be conditioned. In this method, in the event of an emergency being detected, the refrigerant compressor is switched off by means of a vehicle environment sensor system and / or vehicle communication.

With this known method from the DE 10 2012 108 731 A1 However, it is not ensured in all operating states of the vehicle air conditioning system that the amount of refrigerant flowing out is so small that the risk of endangering vehicle occupants is significantly reduced.

From the DE 10 2014 206 392 A1 a vehicle air conditioning system is known whose refrigerant circuit is constructed in such a way that no refrigerant or as little refrigerant as possible can enter the passenger compartment in the event of a crash. This known refrigerant circuit has a refrigerant compressor, a gas cooler, an expansion element and an evaporator. A first shut-off element is connected downstream of the evaporator and is arranged at a location in the vehicle at which the probability that the first shut-off element will be damaged and fail in a crash is comparatively low. Such a location is, for example, behind the front wall of the vehicle when viewed in the direction of travel. Furthermore, a second shut-off device is provided, which is connected upstream of the evaporator and is also arranged at a location in the vehicle at which the probability of damage or failure is low. If a crash is detected, the first and second shut-off devices are closed.

the US 2016/0 129 757 A1 describes a vehicle air conditioning system with a refrigerant circuit which has a refrigerant compressor, an external condenser and an evaporator which is arranged in an air conditioning unit and to which an expansion element is assigned. Furthermore, this refrigerant circuit comprises a refrigerant-coolant heat exchanger as an indirect condenser, which is arranged on the coolant side in a coolant circuit of a vehicle engine. Furthermore, a further refrigerant-coolant heat exchanger is provided as an indirect evaporator, which can be switched into the refrigerant circuit instead of the external condenser and which is also fluidly connected to the coolant circuit of the vehicle engine on the coolant side. This coolant circuit also has a heating register arranged in the air conditioning unit. Furthermore, a temperature sensor for detecting the temperature of the coolant is provided in the coolant circuit, the start-up of the refrigerant compressor being permitted when the temperature of the coolant reaches a threshold value. If, after the refrigerant compressor has started, the high pressure detected by means of a pressure sensor at the outlet of the refrigerant compressor does not rise to a predetermined pressure, it is assumed that the refrigerant has escaped from the refrigerant circuit.

the DE 10 2013 021 360 A1 describes a thermal management system for a motor vehicle with a refrigerant circuit, which enables efficient and active battery cooling and a heat pump process for heating the interior or the battery and whose primary reference variable is a required cooling temperature difference of the cooling medium water-glycol. In the pure cooling mode of the vehicle battery, a refrigerant quality, which corresponds to a certain vapor content, is set at the outlet of a chiller via a position of the expansion element assigned to it close to the dew line of the refrigerant used with minimal power consumption of a refrigerant compressor.

From the DE 100 52 898 A1 a vehicle air conditioning system is known in which the performance of a variable-performance refrigerant compressor can be estimated as a function of a state at a specific point in time. For this purpose, the suction pressure is derived, for example, from the refrigerant temperature at the Detected input side of an evaporator by means of a temperature sensor.

In the case of a refrigerant circuit with a heat pump function, according to DE 10 2011 118 162 A1 Valve elements designed as shut-off elements.

From the U.S. 5,632,156 A a vehicle air conditioning system with a refrigerant circuit having a heat pump function is known. For this known refrigerant circuit, an electrically driven and speed-controlled refrigerant compressor is provided, the high pressure output of which is connected to a four-way valve in order to set line connections for AC operation or heating operation. Check valves are also used here in order to prevent undesired backflows into certain line sections of the refrigerant circuit in a certain operating state.

Also the DE 101 63 607 A1 describes a vehicle air conditioning system with a refrigerant circuit that can be used both for AC operation and heating operation. In order to connect line sections of this refrigerant circuit in a corresponding manner to carry out the different operating states, check valves and shut-off valves are provided.

The object of the invention is to specify a method for limiting a refrigerant escaping from a refrigerant circuit of a vehicle air conditioning system in the event of a collision, with which a higher level of security against the risk to vehicle occupants is achieved than with previously known refrigerant circuits. Another object of the invention is to provide a vehicle air conditioning system with a refrigerant circuit for carrying out the method according to the invention.

The first-mentioned object is achieved by a method having the features of claim 1, claim 2 and claim 5.

1. 1. den Kältemittelkreislauf, welcher
   • 1.1. eine Baugruppe aus einem indirekten Verdampfer mit zugeordnetem Expansionsorgan und einem indirekten Kältemittelkondensator,
   • 1.2 einen Kältemittelverdichter, welcher niederdruckseitig mittels eines am Kältemittelausgang der Baugruppe angeordneten ersten Ventilorgans mit dem indirekten Verdampfer und hochdruckseitig mittels eines am Kältemitteleingang der Baugruppe angeordneten zweiten Ventilorgans fluidverbindbar ist,
   • 1.3 einen saugdruckseitigen Druck-Temperatur-Sensor, und
   • 1.4 einen hochdruckseitigen Druck-Temperatur-Sensor umfasst, und
2. 2. ein Mehrwegeventil, mit welchem der indirekte Verdampfer und der indirekte Kältemittelkondensator kühlmittelseitig mit Innenraum-Wärmetauscher und einem Umgebung-Wärmeübertrager fluidverbindbar sind,

und zur Außerbetriebnahme des Kältemittelkreislaufs folgende Verfahrensschritte durchgeführt werden:

• - Schließen des ersten Ventilorgans,
• - Erfassen der Temperatur- und Druckwerte des saugdruckseitigen Druck-Temperatur-Sensors,
• - Abschalten des Kältemittelverdichters und Schließen des zweiten Ventilorgans, wenn die Temperatur- und Druckwerte des saugdruck-seitigen Druck-Temperatur-Sensors eine Überhitzung des Kältemittels anzeigen.

In this method, corresponding to the first-mentioned solution, for limiting a refrigerant escaping from a refrigerant circuit of a vehicle air conditioning system, the vehicle air conditioning system comprises the following components:

1. 1. the refrigerant circuit, which
   • 1.1. an assembly consisting of an indirect evaporator with an associated expansion element and an indirect refrigerant condenser,
   • 1.2 a refrigerant compressor which can be fluidly connected on the low-pressure side by means of a first valve element arranged at the refrigerant outlet of the assembly to the indirect evaporator and on the high-pressure side by means of a second valve element arranged at the refrigerant inlet of the assembly,
   • 1.3 a pressure-temperature sensor on the suction pressure side, and
   • 1.4 comprises a high-pressure side pressure-temperature sensor, and
2. 2. a multi-way valve with which the indirect evaporator and the indirect refrigerant condenser can be fluidly connected to the interior heat exchanger and an ambient heat exchanger on the coolant side,

and the following process steps are carried out to shut down the refrigerant circuit:

• - closing the first valve member,
• - Acquisition of the temperature and pressure values of the pressure-temperature sensor on the suction pressure side,
• - Switching off the refrigerant compressor and closing the second valve member when the temperature and pressure values of the suction pressure-side pressure-temperature sensor indicate overheating of the refrigerant.

This ensures that after the refrigerant circuit has been switched off, there is only a small amount of refrigerant in the refrigerant lines connecting the refrigerant compressor to the assembly, which could be released into the engine compartment in the event of a crash. Shutting down the refrigerant circuit naturally requires that the refrigerant compressor has been operated at at least the lowest possible speed.

1. 1. den Kältemittelkreislauf, welcher
   • 1.1. eine Baugruppe aus einem indirekten Verdampfer mit zugeordnetem Expansionsorgan und einem indirekten Kältemittelkondensator,
   • 1.2 einen Kältemittelverdichter, welcher niederdruckseitig mittels eines am Kältemittelausgang der Baugruppe angeordneten ersten Ventilorgans mit dem indirekten Verdampfer und hochdruckseitig mittels eines am Kältemitteleingang der Baugruppe angeordneten zweiten Ventilorgans fluidverbindbar ist,
   • 1.3 einen saugdruckseitigen Druck-Temperatur-Sensor, und
   • 1.4 einen hochdruckseitigen Druck-Temperatur-Sensor umfasst, und
2. 2. ein Mehrwegeventil, mit welchem der indirekte Verdampfer und der indirekte Kältemittelkondensator kühlmittelseitig mit Innenraum-Wärmetauscher und einem Umgebung-Wärmeübertrager fluidverbindbar sind,

und zur Inbetriebnahme des Kältemittelkreislaufs folgende Verfahrensschritte durchgeführt werden:

• - Starten des Kältemittelverdichters,
• - Erfassen der Temperatur- und Druckwerte des saugdruckseitigen Druck-Temperatur-Sensors,
• - Erfassen des Druckwertes des hochdruckseitigen Druck-Temperatur-Sensors,
• - Öffnen des ersten Ventilorgans, wenn die Temperatur- und Druckwerte des saugdruckseitigen Druck-Temperatur-Sensors eine Überhitzung des Kältemittels anzeigen, und
• - Öffnen des zweiten Ventilorgans, wenn der Druckwert des hochdruckseitigen Druck-Temperatur-Sensors größer ist als der Druckwert des Kältemittels in dessen Strömungsrichtung nach dem zweiten Ventilorgan.

In the method corresponding to the second-mentioned solution for limiting a refrigerant escaping from a refrigerant circuit of a vehicle air conditioning system, the vehicle air conditioning system comprises the following components:

1. 1. the refrigerant circuit, which
   • 1.1. an assembly consisting of an indirect evaporator with an associated expansion element and an indirect refrigerant condenser,
   • 1.2 a refrigerant compressor which can be fluidly connected on the low-pressure side by means of a first valve element arranged at the refrigerant outlet of the assembly to the indirect evaporator and on the high-pressure side by means of a second valve element arranged at the refrigerant inlet of the assembly,
   • 1.3 a pressure-temperature sensor on the suction pressure side, and
   • 1.4 comprises a high-pressure side pressure-temperature sensor, and
2. 2. a multi-way valve with which the indirect evaporator and the indirect refrigerant condenser can be fluidly connected to the interior heat exchanger and an ambient heat exchanger on the coolant side,

and the following process steps are carried out to start up the refrigerant circuit:

• - starting the refrigerant compressor,
• - Acquisition of the temperature and pressure values of the pressure-temperature sensor on the suction pressure side,
• - Acquisition of the pressure value of the high-pressure side pressure-temperature sensor,
• - Opening the first valve member when the temperature and pressure values of the pressure-temperature sensor on the suction pressure side indicate overheating of the refrigerant, and
• - Opening the second valve member when the pressure value of the high-pressure side pressure-temperature sensor is greater than the pressure value of the refrigerant in its flow direction after the second valve member.

This second solution prevents liquid refrigerant from flowing onto the suction side of the refrigerant compressor when the refrigerant compressor is started and the first valve member is opened at the same time. This second solution therefore ensures that when the refrigerant circuit is started up, only a small amount of refrigerant is present in the refrigerant lines connecting the refrigerant compressor to the assembly, which could be released into the engine compartment in the event of a crash.

The pressure value of the refrigerant is preferably determined in its flow direction after the second valve element by means of a pressure sensor. Alternatively, it is also possible to determine the pressure value of the refrigerant in its flow direction after the second valve element by means of a model calculation on the basis of a temperature value of the refrigerant. This temperature value is detected by means of an existing temperature sensor.

1. 1. den Kältemittelkreislauf, welcher
   • 1.1 eine Baugruppe aus einem indirekten Verdampfer mit zugeordnetem Expansionsorgan und einem indirekten Kältemittelkondensator,
   • 1.2 einen Kältemittelverdichter, welcher niederdruckseitig mittels eines am Kältemittelausgang der Baugruppe angeordneten ersten Ventilorgans mit dem indirekten Verdampfer und hochdruckseitig mittels eines am Kältemitteleingang der Baugruppe angeordneten zweiten Ventilorgans fluidverbindbar ist,
   • 1.3 einen saugdruckseitigen Druck-Temperatur-Sensor, und
   • 1.4 einen hochdruckseitigen Druck-Temperatur-Sensor, und
2. 2. ein Mehrwegeventil, mit welchem der indirekte Verdampfer und der indirekte Kältemittelkondensator kühlmittelseitig mit Innenraum-Wärmetauscher und einem Umgebung-Wärmeübertrager fluidverbindbar sind,

und nach einem Befüllen des Kältemittelkreislaufs mit Kältemittel folgende Verfahrensschritte durchgeführt werden:

• - Öffnen des ersten und zweiten Ventilorgans
• - Erfassen der Temperatur- und Druckwerte des saugdruckseitigen Druck-Temperatur-Sensors,
• - Erfassen der Temperatur- und Druckwerte des hochdruckseitigen Druck-Temperatur-Sensors,
• - Starten des Kältemittelverdichters, und
• - Außerbetriebnehmen des Kältemittelkreislaufs, wenn die Temperatur- und Druckwerte des saugdruckseitigen und hochdruckseitigen Druck-Temperatur-Sensors ein gasförmiges Kältemittel anzeigen, indem zunächst das erste Ventilorgan geschlossen wird und anschließend der Kältemittelverdichter abgeschaltet sowie das zweite Ventilorgan geschlossen werden, wenn die Temperatur- und Druckwerte des saugdruckseitigen Druck-Temperatur-Sensors eine Überhitzung des Kältemittels anzeigen.

In the case of the method corresponding to the third-mentioned solution for limiting a refrigerant escaping from a refrigerant circuit of a vehicle air conditioning system, the vehicle air conditioning system comprises the following components:

1. 1. the refrigerant circuit, which
   • 1.1 an assembly consisting of an indirect evaporator with an associated expansion element and an indirect refrigerant condenser,
   • 1.2 a refrigerant compressor which can be fluidly connected on the low-pressure side by means of a first valve element arranged at the refrigerant outlet of the assembly to the indirect evaporator and on the high-pressure side by means of a second valve element arranged at the refrigerant inlet of the assembly,
   • 1.3 a pressure-temperature sensor on the suction pressure side, and
   • 1.4 a high-pressure side pressure-temperature sensor, and
2. 2. a multi-way valve with which the indirect evaporator and the indirect refrigerant condenser can be fluidly connected to the interior heat exchanger and an ambient heat exchanger on the coolant side,

and after the refrigerant circuit has been filled with refrigerant, the following process steps are carried out:

• - Opening the first and second valve members
• - Acquisition of the temperature and pressure values of the pressure-temperature sensor on the suction pressure side,
• - Acquisition of the temperature and pressure values of the high-pressure side pressure-temperature sensor,
• - Starting the refrigerant compressor, and
• - Shutting down the refrigerant circuit when the temperature and pressure values of the suction pressure side and high pressure side pressure-temperature sensor indicate a gaseous refrigerant by first closing the first valve element and then switching off the refrigerant compressor and closing the second valve element when the temperature and pressure values of the pressure-temperature sensor on the suction pressure side indicate overheating of the refrigerant.

Since after the refrigerant circuit has been filled with refrigerant as part of a vehicle customer service or the assembly of the vehicle at the end of the line, it is evenly distributed in the circuit and, in extreme cases, almost the entire refrigerant charge can be in the refrigerant compressor and the refrigerant lines connecting it to the assembly by means of this third-mentioned solution according to the invention, the refrigerant compressor is operated before the start of the journey in such a way that the refrigerant lines connecting the refrigerant compressor to the assembly also only have a small amount of refrigerant that could be released into the engine compartment in the event of a crash.

An advantageous development of the invention according to the second-mentioned and third-mentioned solution provides that the refrigerant compressor is started with a minimum possible speed. The speed can then be increased.

According to a further preferred embodiment of the invention, the first and the second valve member are each designed as shut-off valves, which are each actively controlled in their blocking state. Alternatively, it is also possible to design the first valve element as a shut-off valve and the second valve element as a check valve. Such a check valve represents a passive valve element and prevents the backflow of refrigerant into the refrigerant line leading to the refrigerant compressor.

If a collision or an impending collision is detected by means of corresponding sensors, the first and the second valve element are closed. This means that only the small amount of refrigerant remaining in the refrigerant lines connecting the refrigerant compressor to the assembly can escape as the maximum possible amount.

The second-mentioned object is achieved by a vehicle air conditioning system with the features of patent claim 10.

1. 1. den Kältemittelkreislauf, welcher
   • 1.1. eine im Vorderwagen des Fahrzeugs angeordnete Baugruppe aus einem indirekten Verdampfer mit zugeordnetem Expansionsorgan und einem indirekten Kältemittelkondensator,
   • 1.2. einen mit einer Antriebseinheit des Fahrzeugs mechanisch verbundener Kältemittelverdichter, welcher zur Herstellung einer niederdruckseitigen Fluidverbindung mit dem indirekten Verdampfer mittels einer Kältemittelleitung mit einem am Kältemittelausgang der Baugruppe angeordneten ersten Ventilorgan fluidverbindbar ist und zur Herstellung einer hochdruckseitigen Fluidverbindung mit dem indirekten Kältemittelkondensatorüber eine Kältemittelleitung mit einem am Kältemitteleingang der Baugruppe angeordneten zweiten Ventilorgan fluidverbindbar ist,
   • 1.3 einen saugdruckseitigen Druck-Temperatur-Sensor, und
   • 1.4 einen hochdruckseitigen Druck-Temperatur-Sensor aufweist, und
2. 2. ein Mehrwegeventil, mit welchem der indirekte Verdampfer und der indirekte Kältemittelkondensator kühlmittelseitig mit Innenraum-Wärmetauscher und einem Umgebung-Wärmeübertrager fluidverbindbar sind.

Such a vehicle air conditioning system with a refrigerant circuit for carrying out the method according to the invention comprises the following components:

1. 1. the refrigerant circuit, which
   • 1.1. an assembly in the front end of the vehicle consisting of an indirect evaporator with an associated expansion element and an indirect refrigerant condenser,
   • 1.2. a refrigerant compressor mechanically connected to a drive unit of the vehicle, which can be fluidly connected to a low-pressure side fluid connection with the indirect evaporator by means of a refrigerant line with a first valve element arranged at the refrigerant outlet of the assembly and to produce a high-pressure side fluid connection with the indirect refrigerant condenser via a refrigerant line with one at the refrigerant inlet the assembly arranged second valve member is fluidly connectable,
   • 1.3 a pressure-temperature sensor on the suction pressure side, and
   • 1.4 has a high-pressure side pressure-temperature sensor, and
2. 2. A multi-way valve with which the indirect evaporator and the indirect refrigerant condenser can be fluidly connected to the interior heat exchanger and an ambient heat exchanger on the coolant side.

The ambient heat exchanger is preferably arranged in the front area of the vehicle, while the interior heat exchangers are arranged as heating heat exchangers and as cooling heat exchangers in an air conditioning unit of the vehicle. The multi-way valve is preferably designed for the optional fluid-conducting connection of the ambient heat exchanger, the heating heat exchanger and the cooling heat exchanger to the assembly.

If the assembly has an indirect evaporator with an associated expansion element and an indirect refrigerant condenser, which are connected via lines carrying coolant to indoor heat exchangers arranged in an air conditioning unit, all refrigerant lines carrying refrigerant are located in the engine compartment. This means that in the event of a vehicle crash, refrigerant cannot flow directly into the passenger compartment. Mounting the refrigerant compressor on a large mass, namely on a drive unit of the vehicle designed as an electrical machine or an internal combustion engine, leads to an acoustic decoupling of the refrigerant compressor from the vehicle body, since such a drive unit itself is a mass that is well decoupled from the vehicle body.

In the event of a collision, damage to the refrigerant compressor and its connected refrigerant lines can therefore occur, but due to the method according to the invention, the amount of refrigerant that escapes is limited to an extremely small amount.

• 1 ein Schaltbild einer Fahrzeugklimaanlage als Ausführungsbeispiel zur Durchführung des erfindungsgemäßen Verfahrens, und
• 2 eine schematische Darstellung eines Vorderwagens eines Fahrzeugs mit den Komponenten der Fahrzeugklimaanlage nach 1.

The invention is described in detail below using an exemplary embodiment with reference to the accompanying figures. Show it:

• 1 a circuit diagram of a vehicle air conditioning system as an embodiment for carrying out the method according to the invention, and
• 2 a schematic representation of a front end of a vehicle with the components of the vehicle air conditioning system according to 1 .

First, the components of a vehicle air conditioning system 1 and their arrangement in Front end 11th of a vehicle 10 based on 1 and 2 and then that with this vehicle air conditioning system 1 feasible method according to the invention explained.

• - eine im Vorderwagen 11 des Fahrzeugs 10 angeordnete Baugruppe 2.0, welche einen indirekten Verdampfer 2.2 mit zugeordnetem Expansionsorgan 2.3 und einen indirekten Kältemittelkondensator 3 aufweist,
• - einen Kältemittelverdichter 2.1, welcher niederdruckseitig mittels einer Kältemittelleitung 2.9 mit einem am Kältemittelausgang 2.01 der Baugruppe 2.0 angeordneten ersten Ventilorgan 2.5 und hochdruckseitig mittels einer weiteren Kältemittelleitung 2.10 mit einem am Kältemitteleingang 2.02 der Baugruppe 2.0 angeordneten zweiten Ventilorgans 2.6 fluidverbunden ist,
• - einen saugdruckseitigen Druck-Temperatur-Sensor 2.7, und
• - einen hochdruckseitigen Druck-Temperatur-Sensor 2.8.

The refrigerant circuit 2 this vehicle air conditioner 1 has the following components for generating hot or cold coolant:

• - one in the front of the car 11th of the vehicle 10 arranged assembly 2.0 , which is an indirect evaporator 2.2 with associated expansion device 2.3 and an indirect refrigerant condenser 3,
• - a refrigerant compressor 2.1 , which on the low pressure side by means of a refrigerant line 2.9 with one at the refrigerant outlet 2.01 the assembly 2.0 arranged first valve member 2.5 and on the high pressure side by means of a further refrigerant line 2.10 with one at the refrigerant inlet 2.02 the assembly 2.0 arranged second valve member 2.6 is fluid-connected,
• - a pressure-temperature sensor on the suction pressure side 2.7 , and
• - a high-pressure side pressure-temperature sensor 2.8 .

With the first valve member 2.5 becomes a low-pressure side fluid connection of the indirect evaporator 2.2 to the refrigerant compressor 2.1 and with the second valve member 2.6 becomes a high-pressure side fluid connection of the refrigerant compressor 2.1 to the indirect refrigerant condenser 2.4 manufactured.

For the distribution of coolant to heat exchangers, namely to an ambient heat exchanger 4th , a heating heat exchanger 5.1 as well as a cooling heat exchanger 5.2 is a multi-way valve 3 provided with the assembly 2.0 is fluid-connected. This becomes the indirect evaporator 2.2 as well as the indirect refrigerant condenser 2.4 each coolant side with this multi-way valve 3 fluid-connected, with which depending on the operating state of the vehicle air conditioning system 1 this heat exchanger with the assembly 2.0 get connected.

The ambient heat exchanger 4th is with a fan 4.1 (also called cooler) as a front end in the front area 13th of the vehicle 10 to form a first coolant circuit K1 arranged. The heating heat exchanger 5.1 as well as the cooling heat exchanger 5.2 are forming a second coolant circuit K2 or a third coolant circuit K3 in an air conditioner 5 arranged, which is according to 2 in the area of an instrument panel 14th of the vehicle 10 is located. Via these coolant circuits K2 and K3 are the two heat exchangers 5.1 and 5.2 likewise with the multi-way valve 3 fluid-connected.

Furthermore, the air conditioner 5 an air damper 5.3 on, with which, for example, an air conditioner 5 supplied air flow L1 after cooling on the cooling heat exchanger 5.2 at least partially also on the heating heat exchanger 5.1 can be passed by for heating in order to then be passed into the vehicle interior with the unheated air flow as supply air flow L2.

A fourth coolant circuit K4 is the same with the multi-way valve 3 connected by one with a drive unit 12th the vehicle's thermally connected cooling heat exchanger 6th is formed. The electrical energy for the electrically operated components is from an energy store 7th made available.

The assembly 2.0 is as a compact unit with the indirect evaporator 2.2 , the associated expansion device 2.3 as well as the indirect condenser and if necessary with a refrigerant collector constructed to be crash-proof and in the area in front of an end wall 15th of the vehicle 10 assembled. In order to achieve the highest possible acoustic decoupling, the refrigerant compressor is 2.1 with the drive unit 12th mechanically connected (cf. 2 ), since this drive unit designed as an internal combustion engine or as an electrical machine 12th itself acoustically good from the vehicle body of the vehicle 10 is well decoupled. Hence the refrigerant compressor 2.1 suction side via the refrigerant line 2.9 with the first valve member 2.5 connected, which at the refrigerant outlet 2.01 the assembly 2.0 is arranged, and via the refrigerant line 2.10 on the high pressure side with the second valve member 2.6 connected, which at the refrigerant inlet 2.02 the assembly 2.0 is arranged. It is also in the refrigerant line 2.9 , i.e. on the suction pressure side of the refrigerant compressor 2.1 a pressure-temperature sensor 2.7 and in the refrigerant line 2.10 , i.e. on the high pressure side of the refrigerant compressor 2.1 another pressure-temperature sensor 2.8 arranged.

In the event of a collision with the vehicle 10 with a vehicle or other obstacle, the two shut-off valves 2.5 and 2.6 locked so that in the event of damage to the refrigerant compressor 2.1 and / or the connected refrigerant lines 2.9 and 2.10 only that in these refrigerant lines 2.9 and 2.10 existing refrigerant in the engine compartment of the vehicle 10 can emerge.

In order to ensure that only a small amount of refrigerant escapes in the event of a crash, the vehicle air conditioning system should be installed at the time of the crash 1 to be in operation. However, is the vehicle air conditioning 1 out of order, it can occur due to unfavorable temperature distributions between the refrigerant compressor 2.1 and the assembly 2.0 a large part of the refrigerant in the refrigerant compressor 2.1 and the refrigerant lines 2.9 (Flow line) and 2.10 (return line) and in the worst case if the refrigerant compressor is damaged by a crash 2.1 and the refrigerant lines 2.9 and 2.10 in the engine compartment of the vehicle 10 step out.

To ensure that regardless of the operating state of the vehicle air conditioning system 1 in the event of a collision, only a minimal amount of refrigerant in the area of the refrigerant compressor at all times 2.1 and its connected refrigerant lines 2.9 and 2.10 is present in the event of damage to the refrigerant compressor 2.1 and / or these refrigerant lines 2.9 and 2.10 The valve elements are likely to leak into the engine compartment 2.5 and 2.6 together with the refrigerant compressor 2.1 to control or operate in a certain way. This applies in the event that the refrigerant circuit is decommissioned 2 , for the case of the commissioning of the refrigerant circuit and for the case of a refrigerant filling, e.g. as part of a customer service or on the production line as part of the assembly of the vehicle.

In the event of the refrigerant circuit being taken out of service 2 the following procedure is carried out.

Before the refrigerant compressor 2.1 is switched off, the first valve member, which is designed as a shut-off valve, is switched off 2.5 closed to any liquid fractions of the refrigerant in the refrigerant line 2.9 and within the refrigerant compressor due to the operation of the refrigerant compressor 2.1 to evaporate. The refrigerant compressor is used to achieve this state 2.1 only switched off when the refrigerant is in the refrigerant line 2.9 is in an overheated state. This state of overheating is detected by means of the pressure-temperature sensor 2.7 The pressure and temperature values generated are determined by evaluating these values by a climate control unit. Will such overheating of the refrigerant in the refrigerant line 2.9 detected by the air conditioning control unit, the refrigerant compressor is 2.1 switched off. At the same time, the second valve element, which is also designed as an active shut-off valve, is also activated 2.6 closed by the climate control unit. This second valve member 2.6 can also be designed as a passive check valve, which is activated after the refrigerant compressor has been switched off 2.1 is automatically closed, ie a backflow of refrigerant into the refrigerant line 2.10 is prevented. With the overheating of the refrigerant in the refrigerant line 2.9 to the refrigerant compressor 2.1 ensures that the refrigerant is in an overheated state.

This ensures that after the refrigerant circuit has been switched off 2 while the vehicle is in motion 10 only a small amount of refrigerant in the refrigerant compressor 2.1 with the assembly 2.0 connecting refrigerant lines 2.9 and 2.10 is present that could be released into the engine compartment in the event of a crash.

In the case of commissioning the refrigerant circuit 2 the following procedure is carried out.

Used when starting the refrigerant compressor 2.1 at the same time the first valve member 2.5 open, it cannot be ruled out that, under certain operating conditions, liquid refrigerant on the suction side of the refrigerant compressor 2.1 , i.e. in the refrigerant line 2.9 flows.

To such an influx of liquid refrigerant into the refrigerant line 2.9 avoid the refrigerant compressor 2.1 started with its minimum possible speed without the suction-side valve element 2.5 is opened. This first valve member 2.5 is only opened when the refrigerant is in the refrigerant line 2.9 to the refrigerant compressor 2.1 is in an overheated state. This state of overheating is detected by means of the pressure-temperature sensor 2.7 generated pressure and temperature values determined by these values are also evaluated by the climate control unit. Will such overheating of the refrigerant in the refrigerant line 2.9 determined by the climate control unit, the first valve element 2.5 opened.

The second valve member designed as a shut-off valve 2.6 is only opened when the value of the high pressure in that of the refrigerant compressor 2.1 outgoing refrigerant line 2.10 via the high pressure within the assembly 2.0 , so in the direction of flow to the second valve member 2.6 connected refrigerant lines has increased. This is in this assembly 2.0 a pressure sensor is arranged, the pressure value of which is fed to the climate control unit for evaluation. Alternatively, this high pressure can occur within the assembly 2.0 also from a temperature value in the module 2.0 arranged temperature sensor can be determined on the basis of a model calculation taking into account a safety margin.

Used as a second valve element 2.6 If a check valve is used, it opens automatically after the refrigerant compressor has started 2.1 as soon as it is in the refrigerant line 2.10 the necessary overpressure has been set.

This ensures that when the refrigerant circuit is commissioned 2 only a small amount of refrigerant in the refrigerant compressor 2.1 with the assembly 2.0 connecting refrigerant lines 2.9 and 2.10 is present that could be released into the engine compartment in the event of a crash.

Finally, it must also be ensured that after the refrigerant circuit has been filled 2 with refrigerant as part of a customer service or as part of the assembly of the vehicle at the end of the line and the subsequent occurrence of a crash, the amount of refrigerant that may escape is reduced to a minimum. The following procedure is carried out for this purpose.

After the refrigerant has been filled, it is usually distributed evenly in the refrigerant circuit 2 , but in extreme cases it can happen that almost the complete refrigerant charge is in the refrigerant compressor 2.1 and the two connected refrigerant lines 2.9 and 2.10 can be located. This is prevented by the fact that the two valve organs, which are designed as shut-off valves, first 2.5 and 2.6 be opened before the refrigerant compressor 2.1 is started. After opening these two valve organs 2.5 and 2.6 becomes the refrigerant compressor 2.1 started with a minimum possible speed, which can then be increased. The refrigerant compressor 2.1 is operated until the refrigerant is in both the refrigerant lines 2.9 and 2.10 as well as in the refrigerant compressor 2.1 is in an overheated state. For this purpose, the pressure and temperature values of the two pressure-temperature sensors 2.7 and 2.8 fed to the climate control unit for evaluation. If these pressure and temperature values indicate an overheated state of the refrigerant, the refrigerant compressor is activated 2.1 switched off by taking the refrigerant circuit out of operation in accordance with the method described above 2 is proceeded. The first valve element is accordingly first 2.5 closed and then the refrigerant compressor 2.1 switched off as well as the second valve element 2.6 closed when the temperature and pressure values of the pressure-temperature sensor on the suction pressure side 2.7 indicate overheating of the refrigerant.

This is in all possible operating cases in which the refrigerant circuit due to a crash 2 in the area of the refrigerant lines 2.9 and 2.10 as well as the refrigerant compressor 2.1 could be opened and thus refrigerant would escape, the maximum amount of refrigerant escaping is limited to a minimum. This is only the one in the refrigerant compressor 2.1 and the associated refrigerant lines 2.9 and 2.10 there are refrigerants, since the refrigerant lines in the event of a crash 2.9 and 2.10 of the two valve organs 2.5 and 2.6 are closed and thus a post-flow of refrigerant from the assembly 2.0 in these refrigerant lines 2.9 and 2.10 is prevented.

Are the valve organs 2.5 and 2.6 each designed as a shut-off valve, NO (normally open) valves can be used for this.

List of reference symbols

1

Vehicle air conditioning

2

Refrigerant circulation

2.0

Refrigerant circuit assembly 2

2.01

Refrigerant outlet of assembly 2.0

2.02

Refrigerant inlet of assembly 2.0

2.1

Refrigerant compressor

2.2

indirect evaporator of the refrigerant circuit 2

2.3

Expansion device of the refrigerant circuit 2

2.4

indirect condenser of the refrigerant circuit 2

2.5

first valve element of the refrigerant circuit 2

2.6

second valve element of the refrigerant circuit 2

2.7

Pressure-temperature sensor of the refrigerant circuit 2

2.8

Pressure-temperature sensor of the refrigerant circuit 2

2.9

Refrigerant line

2.10

Refrigerant line

3

Multi-way valve

4th

Ambient heat exchanger

4.1

fan

5

Air conditioner

5.1

Heating heat exchanger

5.2

Cooling heat exchanger

5.3

Air flap of the air conditioner 5

6th

Cooling heat exchanger

7th

Energy storage

10

vehicle

11

Front end of the vehicle 10

12th

Drive unit of the vehicle 10

13th

Front area of the vehicle 10

14th

Vehicle instrument panel 10

15th

Front wall of the vehicle 10

K1

Coolant circuit

K2

Coolant circuit

K3

Coolant circuit

K4

Coolant circuit

L1

Airflow

Claims (11)

Method for limiting a refrigerant escaping from a refrigerant circuit (2) of a vehicle air conditioning system (1), the vehicle air conditioning system (1) comprising the following components: 1. the refrigerant circuit (2), which 1.1. an assembly (2.0) consisting of an indirect evaporator (2.2) with an associated expansion element (2.3) and an indirect refrigerant condenser (2.4), 1.2. a refrigerant compressor (2.1), which is arranged on the low pressure side by means of a first valve element (2.5) with the indirect evaporator (2.2) arranged at a refrigerant outlet (2.01) of the assembly (2.0) and on the high pressure side by means of a valve element arranged at a refrigerant inlet (2.02) of the assembly (2.0) second valve member (2.6) can be fluidly connected to the indirect refrigerant condenser (2.4), 1.3. a pressure-temperature sensor (2.7) on the suction pressure side, and 1.4. A high-pressure side pressure-temperature sensor (2.8) comprises, and 2. a multi-way valve (3) with which the indirect evaporator (2.2) and the indirect refrigerant condenser (2.4) can be fluidly connected to the interior heat exchangers (5.1, 5.2) and an ambient heat exchanger (4) on the coolant side, and to shut down the refrigerant circuit (2) the following procedural steps are carried out: - closing the first valve member (2.5), - Acquisition of the temperature and pressure values of the pressure-temperature sensor on the suction pressure side (2.7), - Switching off the refrigerant compressor (2.1) and closing the second valve element (2.6) when the temperature and pressure values of the pressure-temperature sensor (2.7) on the suction pressure side indicate overheating of the refrigerant. Method for limiting a refrigerant escaping from a refrigerant circuit (2) of a vehicle air conditioning system (1), the vehicle air conditioning system (1) comprising the following components: 1. the refrigerant circuit (2), which 1.1. an assembly (2.0) consisting of an indirect evaporator (2.2) with an associated expansion element (2.3) and an indirect refrigerant condenser (2.4), 1.2. a refrigerant compressor (2.1), which on the low pressure side by means of a first valve element (2.5) arranged at the refrigerant outlet (2.01) of the assembly (2.0) with the indirect evaporator (2.2) and on the high pressure side by means of a second valve element arranged at the refrigerant inlet (2.02) of the assembly (2.0) (2.6) can be fluidly connected to the indirect refrigerant condenser (2.4), 1.3. a pressure-temperature sensor (2.7) on the suction pressure side, and 1.4. comprises a high-pressure side pressure-temperature sensor (2.8), and 2. a multi-way valve (3), with which the indirect evaporator (2.2) and the indirect refrigerant condenser (2.4) can be fluidly connected to the interior heat exchangers (5.1, 5.2) and an ambient heat exchanger (4) on the coolant side, and for starting up the refrigerant circuit ( 2) the following process steps are carried out: - starting the refrigerant compressor (2.1), - Acquisition of the temperature and pressure values of the pressure-temperature sensor on the suction pressure side (2.7), - Acquisition of the pressure value of the high-pressure side pressure-temperature sensor (2.8), - Opening the first valve member (2.5) when the temperature and pressure values of the pressure-temperature sensor (2.7) on the suction pressure side indicate overheating of the refrigerant, and - Opening the second valve element (2.6) when the pressure value of the high-pressure side pressure-temperature sensor (2.8) is greater than the pressure value of the refrigerant in its flow direction after the second valve element (2.6). Procedure according to Claim 2 , at which the pressure value of the refrigerant in its flow direction after the second valve element (2.6) is determined by means of a pressure sensor. Procedure according to Claim 2 , at which the pressure value of the refrigerant in its flow direction after the second valve element (2.6) is determined by means of a model calculation on the basis of a temperature value of the refrigerant. A method for limiting a refrigerant escaping from a refrigerant circuit (2) of a vehicle air conditioning system (1), the vehicle air conditioning system (1) comprising the following components: 1. the refrigerant circuit (2), which 1.1. an assembly (2.0) consisting of an indirect evaporator (2.2) with an associated expansion element (2.3) and an indirect refrigerant condenser (2.4), 1.2. a refrigerant compressor (2.1), which is arranged on the low pressure side by means of a first valve element (2.5) with the indirect evaporator (2.2) arranged at the refrigerant outlet (2.01) of the assembly (2.0) and on the high pressure side by means of a valve element arranged at the refrigerant inlet (2.02) of the assembly (2.0) second valve member (2.6) can be fluidly connected to the indirect refrigerant condenser (2.4), 1.3. a pressure-temperature sensor (2.7) on the suction pressure side, and 1.4. a high-pressure side pressure-temperature sensor (2.8), and 2. a multi-way valve (3), with which the indirect evaporator (2.2) and the indirect refrigerant condenser (2.4) coolant side with interior heat exchangers (5.1, 5.2) and an ambient Heat exchangers (4) can be fluidly connected, and after the refrigerant circuit (2.) has been filled with refrigerant, the following process steps are carried out: - opening the first and second valve members (2.5, 2.6) - recording the temperature and pressure values of the pressure-temperature sensor on the suction pressure side (2.7), - Recording the temperature and pressure values of the high-pressure side pressure-temperature sensor (2.8), - Starting the refrigerant compressor (2.1), and - Shutting down the refrigerant circuit (2) when the temperature and pressure values of the suction pressure side and high pressure side pressure -Temperature sensor (2.7, 2.8) indicate a gaseous refrigerant by first closing the first valve element (2.5) and connecting it d the refrigerant compressor (2.1) switched off and the second valve element (2.6) closed when the temperature and pressure values of the pressure-temperature sensor (2.7) on the suction pressure side indicate overheating of the refrigerant. Method according to one of the Claims 2 until 5 , in which the refrigerant compressor (2.1) is started with a minimum possible speed. Method according to one of the preceding claims, in which the first and second valve members (2.5, 2.6) are each designed as a shut-off valve. Method according to one of the Claims 1 until 6th , in which the first valve element (2.5) is designed as a shut-off valve and the second valve element (2.6) is designed as a check valve. Method according to one of the preceding claims, in which the first and second valve members (2.5, 2.6) are closed when a collision or an impending collision is detected. Vehicle air conditioning system (1) with a refrigerant circuit (2) for performing the method according to one of the preceding claims, wherein the vehicle air conditioning system (1) comprises the following components: 1. the refrigerant circuit (2), which 1.1. an assembly (2.0) which is arranged in the front end (11) of a vehicle (10) and consists of an indirect evaporator (2.2) with an associated expansion element (2.3) and an indirect refrigerant condenser (2.4), 1.2 a refrigerant compressor (2.1) mechanically connected to a drive unit (12) of the vehicle (10), which is used to establish a low-pressure side fluid connection with the indirect evaporator (2.2) by means of a refrigerant line (2.9) with a refrigerant outlet (2.01) of the assembly (2.0 ) arranged first valve element (2.5) can be fluidly connected and to establish a high-pressure side fluid connection with the indirect refrigerant condenser (2.4) via a refrigerant line (2.10) with a second valve element (2.6) arranged at the refrigerant inlet (2.02) of the assembly (2.0), 1.3 a pressure-temperature sensor (2.7) on the suction pressure side, and 1.4 comprises a high-pressure side pressure-temperature sensor (2.8), and 2. a multi-way valve (3) with which the indirect evaporator (2.2) and the indirect refrigerant condenser (2.4) can be fluidly connected to the interior heat exchangers (5.1, 5.2) and an ambient heat exchanger (4) on the coolant side. Vehicle air conditioning system (1) according to Claim 10 , in which - the ambient heat exchanger (4) is arranged in a front area (13) of the vehicle (10), - the interior heat exchanger as a heating heat exchanger (5.1) and as a cooling heat exchanger (5.2) in an air conditioning unit (5 ) of the vehicle (10) are arranged, and - the multi-way valve (3) is designed for the optional fluid-conducting connection of the ambient heat exchanger (4), the heating heat exchanger (5.1) and the cooling heat exchanger (5.2) with the assembly (2.0) is.

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