CN105627643A

CN105627643A - Refrigeration system with filling level monitoring function

Info

Publication number: CN105627643A
Application number: CN201510830465.4A
Authority: CN
Inventors: 米歇尔·宗内卡尔布; 哈特穆特·贡佩尔; 邦雅曼·黑尔维希; 塞巴斯蒂安·芬克; 菲利普·梅尔
Original assignee: Special Joint-Stock Co Of Kang Wei
Current assignee: Special Joint-Stock Co Of Kang Wei; Konvekta AG
Priority date: 2014-11-25
Filing date: 2015-11-25
Publication date: 2016-06-01
Anticipated expiration: 2035-11-25
Also published as: CN113465200A; CN105627643B; JP2016102647A; DE102014223956B4; DE102014223956A1

Abstract

The invention relates to a method and device used for monitoring refrigerant charge in a refrigerant loop (46) of a refrigeration system; the refrigeration system (10) comprises a compressor (12), a condenser or a gas cooler (14), an expansion device (16) and an evaporator device (18); when the compressor (12) is closed, the method comprises the following steps: measuring at least one temperature, and measuring refrigerant pressure in the refrigeration system; if the measured pressure is out of a nominal pressure scope, determining the refrigerant charge error, when the refrigerant is not enough, the refrigerant nominal pressure is determined according to the measured temperature, and the nominal pressure scope comprises the pressure value having the most regulated deviation from the nominal pressure; when the compressor is opened, the method comprises the following steps: measuring at least one temperature; measuring refrigerant pressure in the exit of the condenser or gas cooler; if the measured pressure is out of the nominal pressure scope, building the refrigerant charge error, especially the refrigerant is not enough, wherein the refrigerant nominal pressure is determined according to the measured temperature, and the nominal pressure scope comprises the pressure value and the pressure value having the most regulated deviation from the nominal pressure; the device also comprises a container (22) used for storing refrigerant; the refrigerant is specially CO2; the device runs in a cross critical range according to work points; at least one refrigerant temperature sensor (32) and at least one refrigerant pressure sensor (34) are provided so as to measure the temperature and pressure of the refrigerant; the refrigerant temperature and pressure can be evaluated in the mode in a control unit (30), so the refrigerant charge error can be detected if the insufficiency is detected, the control unit can control medium on the refrigerant loop (46) so as to start filling.

Description

There is the refrigeration system of filling extent monitoring

Technical field

The present invention relates to a kind of method, for monitoring the refrigerant charge of the refrigerant loop of refrigeration system, to fill such refrigeration system by cold-producing medium, and relate to a kind of device especially for vehicle, for monitoring the refrigerant charge of refrigeration system.

Background technology

Compression refrigerating system or air conditioning system are such as used for air-conditioning vehicle as air conditioning system, for instance automobile or bus, to reduce the temperature of vehicle interior. The compression refrigerating system of the above-mentioned type includes the cryogen delivery system with condenser unit, this condenser unit includes at least one condenser or at least one gas cooler, additionally also having expansion gear, evaporator unit and compressor, they are linked together by cold-producing medium pipeline. Cold-producing medium circulates in this closed-loop path.

According to Environmental compatibility, carbon dioxide (CO₂) as cold-producing medium, as the substitute medium for compression refrigerating system. Compared with other cold-producing medium, naturally occurring material carbon dioxide has low-down weather destructiveness global warming up trend. CO₂The low-down only critical temperature of 31 DEG C that one drawback is that it, for this reason, heat release must carry out on critical pressure and will not condense/liquefy. CO₂Critical pressure be about 74 bars. With CO₂For, in the known compression refrigerating system of cold-producing medium, filling relative to the system of system bulk, also referred to as filling extent, for the 50%��100% of critical density. High-pressure section does not condense, because high pressure is higher than critical pressure.

When such compression refrigerating system operationally, of a relatively high operating pressure is preponderated in the downstream of compressor, and relatively low pressure is preponderated in the upstream of compressor. Occur that when system remains static pressure is balanced, and still relatively higher static pressure is set up in the loop of compression refrigerating system. Compressor must be designed and provide suitable protection for this of a relatively high static pressure. The system temperatures of 40 DEG C and be about refrigerant carbon dioxide the filling extent of critical density 50% under, system pressure is about 75 bars, and cold-producing medium critical density region filling extent place its be about 89 bars. The system temperatures of 60 DEG C and be about refrigerant carbon dioxide the filling extent of critical density 50% under, system pressure is about 89 bars, and cold-producing medium critical density 100% filling extent place its be about 124 bars.

Reliably determining the filling extent of refrigerant loop, the amount of the cold-producing medium namely existed in refrigerant loop, is required, especially for identifying lack of refrigerant. Limit the refrigerant charge for specific air conditioning system or refrigeration system to preferably must be held in very strict tolerance, because any excessive or deficiency in systems may result in refrigeration performance and reduces, or even damage system. Particularly when there is deficiency, in fact it could happen that unstable situation, this temporary fault being likely in some cases even result in loop. The filling extent of compression refrigerating system is usually to be determined in the process of idle condition analysis, and the pressure of cold-producing medium is measured by pressure transducer, and relevant with the temperature of cold-producing medium.

Using carbon dioxide as in the development further of the known compression refrigerating system of cold-producing medium, wherein carbon dioxide is a kind of non-flammable, burning inertia, nontoxic and at the standard conditions for the medium of harmless gaseous state material, the carbon dioxide from compression refrigerating system can as firing-fighting medium in suitable vehicle fire extinguishing system. Cold-producing medium CO₂Therefore the applicable extinguishing chemical for extinguishing any burning things which may cause a fire disaster that can occur or caused by vehicle accident is had proved to be. Firing-fighting medium CO₂Have superiority than the cooling glassware for drinking water used in a similar fashion.

US5481884 discloses under static state also having the method for refrigerant charge monitoring in the running of air-conditioning and heat pump. At the system run duration of continuous service, the temperature and pressure of cold-producing medium is measured on the suction side of compressor. Under the pressure recorded, set up the saturation temperature being associated and it can be used as fiducial temperature, comparing with the refrigerant temperature recorded with it. If the temperature recorded is higher than fiducial temperature, then it is assumed to deficiency.

DE10061545A1 discloses under static state and/or has in running the method for the refrigerant charge monitoring in the air-conditioning of compressor and cold-producing medium or the refrigerant loop of heat pump, and described cold-producing medium is according to operating point at postcritical range of operation. In the process running charging amount monitoring, refrigerant superheat detected, namely rise in system evaporator place temperature, and overheated compared with limits value by what detect. The maximum specified is exceeded, it assumes that report to the police accordingly instruction for deficiency generating if overheated.

And from US5481884 and DE10061545A1 known method can really in principle be applicable to any cold-producing medium, therefore be also applied for CO₂, but described method only identifies in suction port of compressor, i.e. wrong refrigerant condition in low-pressure side. But, error condition also can such as occur due to the obstruction of defective swelling part or refrigerant loop. Compressor is all constituted serious risk by fault two kinds possible.

DE4411281B4 discloses automotive air conditioning systems, and it uses CO₂As circulatory mediator, the wherein circulatory mediator CO of air conditioning system₂Extinguishing chemical when occurring as fire intentionally. Within air-conditioning systems, circulatory mediator circulates in pressure line, wherein has the electromagnetic valve controlled by control unit being disposed thereon the fire extinguishing circuit terminated at fighting nozzle, from described pressure line branch. It is supplied to the CO of extinguishing device₂Usually contain the lubricant used in circulatory mediator, for lubricating movement part.

Invention summary

Refrigerant charge that the present invention proposes the refrigerant loop for monitoring refrigeration system the method filling such refrigeration system by cold-producing medium, and for monitoring the device of the refrigerant charge of refrigeration system, wherein cold-producing medium can use as firing-fighting medium. Especially, the present invention can monitor reliably in the continuous service process of refrigeration system. The method proposing this monitoring refrigerant charge in refrigerant loop is the refrigeration system for compression refrigerating system form.

Monitored compression refrigerating system is for regulating the air themperature in vehicle, including the cryogen delivery system with condenser unit, this condenser unit includes at least one condenser or at least one gas cooler, expansion gear, evaporator unit and compressor, they are linked together by cold-producing medium conveying circuit. Independent expansion tank can be connected to refrigerant loop by valve, and wherein this expansion tank is arranged in low-pressure side at expansion device downstream especially. For example, it is desired to for detecting the state that the temperature sensor of temperature and pressure comes in monitoring circuit. Cold-producing medium circulates in this closed-loop path. Such system adopts the form of Trans-critical cycle system, and namely it is Trans-critical cycle design, and wherein carbon dioxide is as cold-producing medium.

During the refrigerant charge change existed in refrigerant loop, different parameters value changes at the diverse location of refrigerant loop, and wherein these parameters are to fill sensitive measurand. In Trans-critical cycle compression refrigerating system, the change of refrigerant charge is relevant with the pressure change of refrigerant loop middle finger allocation, and such pressure can be considered as fill sensitive parameter. The change of the refrigerant temperature of refrigerant loop middle finger allocation is also relevant with the change of refrigerant charge. It is also considered as filling sensitive parameter in the change that the cold-producing medium of condenser unit outlet is supercool. The pressure transducer arranging suitably placement in refrigeration systems for detection pressure and arranges the temperature sensor suitably placed for detection temperature. According to the solution that the present invention proposes, temperature sensor may be provided in refrigeration system, between the outlet of condenser or gas cooler and the entrance of swelling part.

If positively identifying deficiency, then on high-pressure side, determine that the state of filling extent is advantageous for. It is particularly advantageous for taking in for both states (namely on high-pressure side and low-pressure side), especially in conjunction with the method described in DE10061545A1.

The value of each filled sensitive parameter makes to evaluate the refrigerant charge being present in refrigerant loop and is possibly realized. If realizing good refrigeration performance, it is also possible to the refrigerant charge that the form of filling extent represents should change in strict limit. Cold-producing medium filling extent is defined as the business of refrigerant charge and total system bulk.

Compressor proceeds charging amount monitoring when closing. Balanced system pressure then follows evaporating pressure, it is provided that remain the cold-producing medium that liquid does not evaporate. Reference temperature is the minimum temperature in system.

P (T)=p_crit��((T/T_crit+a)��b)^c+d

Substitute into corresponding to those for cold-producing medium CO₂Value create following:

P (T)=73.834 (((T+273.15)/304.21 0.350042) 1.54159)^4.31458�C0.810014.

T should here by DEG C in units of substitute into, and p is with bar_DefinitelyObtain for unit.

Once evaporate, along with the rising of temperature, pressure follows the isochore corresponding to filling extent. For this, suitable value must substitute in this thermal equation of state. Evaporating pressure at the identical temperature of this pressure ratio is low. Simple thermal equation of state is such as vanderWaals equation and Redlich-Kwong equation.

VanderWaals equation is:

P (T)=R*T/ (v-b) a/v²

Wherein a=27/64* (R*T_crit)²/p_crit, b=R*T_crit/(8*p_crit)

If substituting into CO₂And 260kg/m³The value of filling extent, gained is as follows:

P (T)=189*T/ ((1/260)-0.0009732) 188.81/ (1/260)²

Wherein p think Pa be unit, T in units of K,

Or

P (T)=((T+273.15) * 65,773 12763586)/100000

Wherein P is with bar_DefinitelyFor unit, and T by DEG C in units of.

Redlich-Kwong equation is:

P (T)=R*T/ (v-b) a (T)/(v²+bv)

Wherein a=0.42748* (T/T_crit)^-0.5*(R*T_crit)²/p_crit, b=0.08664*R*T_crit/p_crit

If substituting into CO₂Value and 260kg/m³Filling extent, gained is as follows:

P (T)=189*T/ ((1/260)-0.00067454)-191.32* (T/304.21)^-0.5/((1/260)²+0.00067454/260)

Wherein p is in units of Pa, and T is in units of K

Or

P (T)=((T+273.15) * 59580 191916760* (T+273.15)^-0.5)/100000

Wherein P is with bar_DefinitelyFor unit and T by DEG C in units of.

Temperature outside refrigerant loop, for instance the internal temperature of vehicle or external temperature, can as reference temperature. It is also possible, however, to use the temperature measured in refrigerant loop, for instance by the evaporator temperature that freezing sensor is measured. If measuring multiple temperature, then advantageously use the minimum temperature recorded.

Especially, open compressor and proceed charging amount monitoring, namely by suitable sensor device in continuous service process, wherein determine the measurand depending on refrigerant charge. In this case, the pressure and temperature of cold-producing medium is by the pressure transducer and the temperature sensor detection that suitably position (namely in the upstream in the downstream of compressor and condenser unit particularly gas cooler and expansion gear) on the high-pressure side of refrigerant loop. If measured refrigerant pressure with detect temperature correlation connection appointment nominal pressure scope outside, detected value by assuming that filled error be estimated. If the pressure measured is lower than specifying nominal pressure scope, or lower than the minimum pressure specified based on nominal pressure, this minimum pressure is corresponding to the minimum pressure specified and thus the minimum charging amount specified corresponding to cold-producing medium depend on current refrigerant temperature, lack of refrigerant in then supposition system also produces corresponding signal, and it is on-stream arranges further step. Such as, exporting caution signals, it sound and/or visual form can be output as information on services.

In a preferred embodiment, further step according to the proposed method includes utilizing cold-producing medium automatically to fill refrigerant system, and wherein cold-producing medium is such as stored in the storage container being integrated in this system, and is supplied by controlled distribution device. This allotter especially includes the Controlled valve unit with electromagnetic valve and check-valves, described electromagnetic valve and check-valves stay open until the pressure transducer being arranged on condenser unit or gas cooler or condenser downstream detects that the pressure of cold-producing medium is within the scope of nominal pressure, and this is corresponding to the nominal pressure based on the temperature in condenser unit outlet detection.

For the purposes of the present invention, this term nominal pressure scope refers to the pressure limit of force value, and it deviates nominal pressure at most such as +/-10% tolerance, also refers to fixed limit pressure, and this determines on the basis of temperature, to reach maximal efficiency. Described nominal pressure obtains by optimizing the refrigerating capacity relevant with compressor shaft power. A parameter in optimization is the refrigerant temperature in the exit at heat radiation gas cooler, and the nominal pressure needed for wherein reaching maximal efficiency is the thermodynamic data by the cold-producing medium used or is determined by suitably measuring of nominal pressure.

The nominal pressure of cold-producing medium is probably to determine on the temperature basis that condenser or gas cooler exit are set up. Described nominal pressure can such as be determined by the linear equation according to following relationship or partial linear equation in the simplest situations:

P (T)=90+2 (T 35), wherein p substitutes in units of bar, T by DEG C in units of,

Or

P (T)=74+2 (T 31+5), wherein P substitutes in units of bar, T by DEG C in units of.

When substituting into critical pressure 74 bar, critical temperature 31 DEG C and supposing the degree of supercooling of 5 DEG C, it is thus achieved that slightly higher nominal pressure.

Being directed to use with vapor curve for measuring and producing the another kind of method of better result, and on critical temperature, it is extrapolated, wherein the specific degree of supercooling of such as 5K magnitude is specified. The actual relationship of steam pressure is:

P (T)=p_crit��((T/T_crit+a)��b)^c+d

Substitute into for cold-producing medium CO₂Analog value, gained is as follows:

P (T)=73.834 (((T+273.15)/304.21-0.350042) 1.54159)^4.31458�C0.810014��

T should here by DEG C in units of substitute into, and p is with bar_DefinitelyObtain for unit. Utilizing the degree of supercooling of 5 DEG C, the nominal pressure obtained is:

P (T)=73.834x (((T+278.15)/304.21-0.350042) 1.54159)^4.31458-0.810014��

Accurately determine the nominal pressure of the best by it needs to be determined that acquired refrigeration performance and compressor horsepower for this purpose. But, this will need the other pressure and temperature sensor in suction port of compressor and exit, and this will need sizable extraneous expense. For described reason, simple, approximate determine it is preferred under existing conditions by linear equation or by what steam pressure was extrapolated. High-pressure side in Trans-critical cycle compression refrigerating system, it is possible to utilize the 5K degree of supercooling in gas cooler downstream to realize good steam pressure extrapolation. The pressure of about 80 bars is preponderated the temperature of 30 DEG C, and the pressure of about 90 bars is preponderated the temperature of 35 DEG C, and the pressure of about 100 bars is preponderated the temperature of 40 DEG C.

The nominal pressure value that can compare with measurement pressure can be defined based on the limiting pressure curve drawn on temperature/pressure figure and the temperature value determined. Based on the comparison of measured pressure and nominal pressure, it is assumed that the refrigerant charge error in refrigerant loop. Especially, if the pressure recorded is outside the nominal pressure scope specified, assuming that deficiency, this nominal pressure scope is determined by the specified tolerances in the temperature of nominal pressure and detection.

When deficiency being detected, run compression refrigerating system and filled by the charging port being arranged on the suction side of compressor from storage container in a controlled manner. In interchangeable embodiment, this refrigerant system is filled by external source, for instance in the process that workshop is visited.

In one embodiment, integrated storage container within the system, for instance take to fill the form of (top-up) cylinder, it is fixedly provided in vehicle, such as in the luggage compartment of vehicle or groove, thus not in the region of enging cabin, the temperature wherein raised is preponderated. Especially, the charging port with electromagnetic valve and check-valves may be provided on the suction side of compressor, is incorporated in refrigerant loop by the cold-producing medium of its ormal weight. Armed with gaseous refrigerant, the charging port of this storage container is positioned in the upstream of evaporator or the low-pressure side in downstream. But, armed with liquid refrigerant, then this charging port is positioned at the upstream of evaporator.

When deficiency being detected in refrigeration systems, the pressure of cold-producing medium is too low, utilizes cold-producing medium to supplement refrigeration system, wherein such as utilizes the compressor of unlatching, persistently supplements until reaching the nominal pressure specified.

It may, however, also be such situation, pressure in refrigeration systems is so low, to such an extent as to compressor has passed through low tension switch and closes. When compression refrigerating system remains static, between the high-pressure side and low-pressure side of refrigeration system, occur in that pressure is balanced, described equilibrium includes expansion gear, evaporator until the region of suction port of compressor, and sets up counterpressure in the refrigerant loop of system. In this case, refrigerant system is supplemented by from the cold-producing medium stored in container at first, compressor need not be opened, until the pressure equilibrium between system and storage container or until reaching the unlatching pressure of the low tension switch of compressor, and proceed further filling after compressor is opened, until pressure is within the scope of nominal pressure.

On the basis of the relation between the pressure of cold-producing medium and the temperature of cold-producing medium or comparable temperature, evaluating the filling extent of refrigerant loop by this way, filling error thus setting up. This fill evaluate by pressure, temperature and fill between relation based on. Evaluation result from filled error can as the triggering event being filled refrigerant loop by integrated storage container, and the checking wherein filled is possible. The circuit controlled by valve cell opens compressor, proceeds to fill and filled error compensation therefore, wherein fills sensitive parameter pressure and temperature and utilize corresponding sensor to measure. When filled sensitive parameter pressure and temperature returns within the scope of the nominal pressure of regulation, by such as by the corresponding control signal sent to valve cell, stopping the feeding from the cold-producing medium in storage container, and cancel any warning exported. Can keeping that specifies to fill by this way, this is the prerequisite of refrigeration system lossless refrigeration performance to greatest extent.

Described storage container is connected to described refrigerant loop, wherein in the low-pressure side of its described compression refrigerating system being arranged on the circuit of the downstream of evaporator and the upstream of compressor suction side by valve cell. In one embodiment, the storage container storing this cold-producing medium includes heater, to increase temperature and thus the pressure that increases in storage container so that this refrigerant system padding can greatly speed up and shorten.

Additionally, the cold-producing medium being stored in storage container, particularly CO₂, can be used as the firing-fighting medium of vehicle fire extinguishing system. There is provided and cold-producing medium CO is provided when needed₂As the extinguishing device of firing-fighting medium, for the burning things which may cause a fire disaster caused in vehicle or by vehicle accident can be there is, particularly in enging cabin. According to the present invention, described cold-producing medium is storable in storage container, and can be used for filling refrigeration system and for extinguishing device. This extinguishing device includes extinguishing chemical circuit and nozzle, and its possible burning things which may cause a fire disaster place in vehicle sensitive region terminates. If it occur that collision and/or fire, self-extinguishing program can be undertaken by suitable sensing system, the CO wherein stored₂, particularly oil-free, by this way the oxygen in air is discharged from fire hazard region, to implement to avoid the preventive measure of fire. Especially, the carbon dioxide being stored in storage container is oil-free, unlike the cold-producing medium of conveying in refrigerant loop, owing to the lubricating oil dissolubility used within the compressor raises, and entrained oil on high-pressure side.

If it occur that collision and/or fire, triggering self-extinguishing program, the oxygen participated in the air that fire occurs is discharged by the cold-producing medium wherein occurred, without the oil carrying any fire hazard that overheated position be will be further increased.

Accompanying drawing is sketched

The illustrative embodiments of the present invention will be explained in greater detail with reference to accompanying drawing.

In the accompanying drawings:

Fig. 1 illustrates have cold-producing medium CO₂And monitor the refrigeration system of refrigerant charge and the schematic block diagram of extinguishing device;

Fig. 2 illustrates that the refrigeration system of Fig. 1 utilizes and controlled is filled in the flow chart monitoring refrigerant charge in the operation being performed continuously over,

Fig. 3 illustrates in different evaporating temperatures from the chart of relation between temperature and the relevant nominal pressure of the cold-producing medium after gas cooler appearance,

Fig. 4 illustrates the chart of relation between the temperature and pressure of the cold-producing medium after having the occurring from gas cooler of 5K degree of supercooling, and contrast is the vapor curve of extrapolation on the critical point of cold-producing medium,

Fig. 5 illustrates have the chart of relation between temperature and the coefficient of performance of refrigerating of the cold-producing medium after 5K degree of supercooling occurs from gas cooler in different evaporating temperatures,

Fig. 6 illustrates at best coefficient of performance of refrigerating from the chart of relation between temperature and the filling extent of the cold-producing medium after gas cooler appearance,

Fig. 7 illustrates for measuring the Pressure gauge with temperature scale of the pressure and temperature of cold-producing medium when compressor is closed, and

Fig. 8 illustrates when compressor is opened for measuring the Pressure gauge with temperature scale of the pressure and temperature of cold-producing medium.

Various embodiments

Fig. 1 is the schematic diagram of refrigeration system 10, and it utilizes cold-producing medium CO₂Run, and can use on vehicle. CO₂It is also referred to as carbon dioxide and R-744. Refrigeration system 10 includes the closed refrigerant circuit 46 with compressor 12, arranges gas cooler 14 downstream on high-pressure side. The latter is followed by expansion gear 16, and the circulating refrigerant passed through at this by it is supplied to evaporator 18 with the form expanded and cool down, and it is connected to compressor 12 in suction side 20. Each assembly 12,14,16 and 18 of refrigeration system 10 is linked together by pressure line 19.

Storage container 22, wherein storage has certain amount of cold-producing medium, is connected to suction side 20 or is connected to the relevant pressure circuit 19 between the outlet side of evaporator 18 and the entrance of compressor 12 or suction side 20. Storage container 22 is connected to pressure line 19 by valve cell 24, and valve cell 24 such as includes electromagnetic valve and check-valves (not shown). Additionally, storage container 22 can include heater 48, wherein ascending temperature adds the pressure of the cold-producing medium being stored in storage container 22, and this helps speed up filling.

Air stream 26 to be cooled is carried by evaporator 18, and this air stream such as blows in the inside of vehicle. Gas cooler 14 is cooled down by the air stream 28 being transported away by described cooler. Further there is illustrated at least one control unit 30, it controls the operation of refrigeration system 10 in a conventional manner. Additionally, at least one control unit 30 controls the monitoring to refrigerant charge together with detecting device, this will be further explained.

May infer that from Fig. 1, if refrigerant charge error being detected in refrigeration system 10, then sending signal from least one control unit 30 to alarm device 31, the information wherein exporting alarm device 31 provides the information of the charging amount error about refrigeration system 10.

Detecting device includes refrigerant temperature sensors 32 and refrigerant pressure sensor 34, and it is arranged on the outlet side 35 of gas cooler 14. At least one control unit 30 described receives the measurement signal from described sensor 32 and 34, and assesses them according to the method for monitoring refrigerant charge, and this carries out during the continuous service of this refrigeration system.

Fig. 1 illustrates fire extinguishing circuit 36, represents multiple such circuit, and it is from storage container 22, terminates at the fire risk point of vehicle engine compartments. Fighting nozzle 38 is arranged on the terminal of fire extinguishing circuit 36. The electromagnetic valve 40 connecting at least one control unit 30 by controlling circuit 42 is arranged in fire extinguishing circuit 36. At least one control unit 30 processes the signal of sensor 44, its detection collision and/or fire. Such as, sensor 44 can be crash sensor, and it can take belt tensioner and/or air bag or the form of independent crash sensor. Alternatively or additionally, corresponding sensor 44 may also comprise the temperature sensor being arranged in potential fire location as fire sensor. The deformation-sensor that can detect damage can be comprised additionally in. Just in case there is the fire caused by accident or damage, the electromagnetic valve 40 in fire extinguishing circuit 36 is driven by least one control unit 30, and described electromagnetic valve is opened so that from the cold-producing medium CO of storage container 22₂In a controlled manner by putting out a fire circuit 36 from fighting nozzle 38 out, and on purpose extinguish burning things which may cause a fire disaster or prophylactically make height flammability regime contact CO₂��

Fig. 2 illustrates the flow chart of the refrigerant charge of the refrigeration system 10 monitoring Fig. 1 during utilizing the controlled operation being filled in and being performed continuously over.

In the beginning 99 of the refrigerant charge of monitoring refrigeration system 10, in first step 100, refrigerant temperature T_KMmessIt is sent to control unit 30 and refrigerant pressure p by the refrigerant temperature sensors 32 being arranged on the outlet side 35 of gas cooler 14_KMmessIt is sent to control unit 30 by being similarly disposed at the refrigerant pressure sensor 34 of same position. Then, check whether the compressor 12 of refrigeration system 10 is opened in a step 102. Hereinafter relate to the situation that compressor 12 is opened.

If compressor 12 is to close, for instance because the pressure measured is so low, compressor 12 is automatically switched off by low tension switch, carry out the pressure between high-pressure side and low-pressure side in a step 101 balanced. In this case, control unit 30 can open valve cell 24, and thus cold-producing medium outflow storage container 22 enters in refrigerant loop 46, until certain degree. Then under compressor 12 is opened, proceed the further filling of refrigerant loop 46, as described below.

When compressor 12 is opened, setting up at step 104 can with the refrigerant temperature T measured_KMmessRelevant nominal pressure p_soll(T), various approximation can wherein be used. Refrigerant charge error can be verified from the refrigerant temperature set up and the refrigerant pressure set up, and based on the contrast with the limit pressure or nominal pressure of temperature correlation. Here, measured pressure and temperature value is compared with limiting pressure curve, and it represents the limit pressure of relevant reference temperature value, and accordingly acts as the basis of checking refrigerant charge error.

In step 106, control unit 30 determines whether the refrigerant pressure p of measurement_KMmessOutside nominal pressure scope, this nominal pressure scope is positioned at minimum pressure p_minWith maximum pressure p_maxBetween. Especially, minimum pressure p_minBy nominal pressure p_soll(T) the �� P and with it deviateing a tolerance determines, for instance allow and nominal pressure p_soll(T) tolerance of +/-10%. Nominal pressure p_soll(T) minimum pressure specified corresponding to cold-producing medium, and therefore correspond to the minimum charging amount of regulation, and depend on current refrigerant temperature T_KMmess��

If the refrigerant pressure p measured_KMmessIn the margin of tolerance covered, monitoring process is at done state 115 and terminates. If the refrigerant pressure p measured_KMmessLower than low appointment minimum pressure p_min, then control unit 30 recognizes this is refrigerant charge error or the deficiency of refrigerant loop 46, and produces further step. One step 108 creates warning, and it exports in an appropriate manner.

Further step 110 relates to automatically and controllably filling refrigeration system 10 when cold-producing medium is stored in storage container 22.

Control unit 30 opens valve cell 24 so that the cold-producing medium from storage container 22 is supplied to the refrigerant loop 46 on the suction side 20 of compressor 12 by pressure line 19, until the lack of refrigerant in refrigeration system 10 is compensated. The filling of refrigeration system 10 is accompanied by the refrigerant pressure p measured in step 112_KMmessWith nominal pressure p_soll(T) contrast. If the refrigerant pressure measured deviate from the tolerance that +/-is determined within the scope of nominal pressure with nominal pressure, for instance 2%, control unit 30 exports signal to terminate filling and cancelling warning in step 114. The program that is subsequently filled at done state 115 and terminates.

Fig. 3 show from gas cooler 14 occur after, by DEG C in units of measurement refrigerant temperature T_KMmessRelevant nominal pressure p with the refrigerant carbon dioxide in units of bar_soll(T) chart of relation between. Here the first curve K1 shows the prescribed relationship at the evaporating temperature t0 of+10 DEG C, and the second curve K2 shows the prescribed relationship at the evaporating temperature t0 of-10 DEG C.

Fig. 4 be the refrigerant carbon dioxide illustrate the occurring from gas cooler 14 of the constant filling refrigerant loop 46 with 5K degree of supercooling by the 3rd curve K3 after by DEG C in units of measurement refrigerant temperature T_KMmessAnd in units of bar pressure p between the chart of relation. By contrasting, on chart, also depict the vapor curve K4 of the extrapolation of the critical point PC beyond refrigerant carbon dioxide.

Fig. 5 show from gas cooler 14 occur after refrigerant carbon dioxide by DEG C in units of measurement refrigerant temperature T_KMmessAnd there is the chart of relation by way of example between the coefficient of performance of refrigerating �� of 5K degree of supercooling. Here the 5th curve K5 shows the prescribed relationship at the evaporating temperature t0 of+10 DEG C, and the 6th curve K6 shows the prescribed relationship at the evaporating temperature t0 of-10 DEG C.

Fig. 6 be illustrate by way of example from gas cooler 14 occur after refrigerant carbon dioxide by DEG C in units of measurement refrigerant temperature T_KMmessAnd the chart of relation between the filling extent F of best coefficient of performance of refrigerating �� in units of g/ litre. In selected example, evaporating temperature T0 amounts up to 0 DEG C, and compressor 12 has an effective percentage of 0.8, and the volume of gas cooler 14 is about the twice of volume of evaporator 18.

Fig. 7 illustrates the manometric example with temperature scale, for measuring the refrigerant pressure p in units of bar when compressor 12 is closed_KMmessWith by DEG C in units of the refrigerant temperature T of refrigerant carbon dioxide_KMmess. In an example shown, filling extent amounts to and is about 260g/L. In this case, refrigerant carbon dioxide is liquid condition.

Fig. 8 illustrates the manometric example with temperature scale, for measuring the refrigerant pressure p in units of bar when compressor 12 is opened_KMmessWith by DEG C in units of the refrigerant temperature T of refrigerant carbon dioxide_KMmess. In an example shown, degree of supercooling is about 5K. In this case, refrigerant carbon dioxide is in supercriticality.

The invention is not limited in described exemplary embodiment and this place emphasize in. On the contrary, in the scope that claim limits, the multiple amendments in those skilled in the art's ability are possible.

Reference numerals list

10 refrigeration systems

12 compressors

14 gas coolers

16 expansion gears

18 evaporators

19 pressure lines

20 suction sides

22 storage containers

24 Controlled valve unit

26 air streams to be cooled

The 28 air streams being transported away by gas cooler

30 control units

31 alarm devices

32 refrigerant temperature sensors

34 refrigerant pressure sensor

The outlet side of 35 gas coolers

36 fire extinguishing circuits

38 fighting nozzles

40 electromagnetic valves

42 control circuit

44 for detecting the sensor of collision and/or fire

46 refrigerant loops

48 heaters

99 start

100 ... 114 steps

115 final states

F filling extent

P pressure

PC critical point

p_KMmessRefrigerant pressure

p_soll(T) nominal pressure

T0 evaporating temperature

T_KMmessRefrigerant temperature

�� coefficient of performance of refrigerating

K1 the first curve

K2 the second curve

K3 the 3rd curve

K4 vapor curve

K5 the 5th curve

K6 the 6th curve

Claims

1. the method being used for monitoring the refrigerant charge in the refrigerant loop (46) of refrigeration system (10), this refrigeration system (10) has compressor (12), condenser or gas cooler (14), expansion gear (16) and evaporator (18), and charging amount monitoring when wherein compressor (12) is closed comprises the following steps:

-measure at least one temperature of cold-producing medium in the refrigerant loop (46) at evaporator (18) place and the refrigerant temperature in the refrigerant loop (46) at condenser or gas cooler (14) place;

-measure the refrigerant pressure in refrigeration system (10);

If the pressure of-measurement is beyond nominal pressure scope, set up refrigerant charge error, particularly lack of refrigerant, wherein the nominal pressure of cold-producing medium is determined based on minimum measurement temperature, and nominal pressure scope includes the force value that at most deviates the tolerance of regulation with nominal pressure.

2. method according to claim 1, it is characterised in that measure the temperature outside refrigerant loop (46).

3. according to the method one of in claim 1 to 2, it is characterised in that the nominal pressure of cold-producing medium is evaporating pressure and according to the refrigerant temperature minima at the gas pressure of the cold-producing medium of the gas density of regulation.

4. method according to claim 3, it is characterised in that the gas density of defined adds up to 260g/l.

5. according to the method one of in Claims 1-4, it is characterised in that if pressure lower than nominal pressure more than 10%, then it represents that have deficiency.

6. according to the method one of in claim 1 to 5, it is characterised in that this cold-producing medium is CO₂��

7. the method being used for monitoring the refrigerant charge in the refrigerant loop (46) of refrigeration system (10), this refrigeration system (10) has compressor (12), condenser or gas cooler (14), expansion gear (16) and evaporator (18), and charging amount monitoring when wherein compressor (12) is opened comprises the following steps:

-measure at least one refrigerant temperature in the refrigerant loop (46) at condenser or gas cooler (14) place;

-measure the refrigerant pressure at condenser or the exit of gas cooler (14);

If the pressure of-measurement is beyond nominal pressure scope, set up refrigerant charge error, particularly lack of refrigerant, wherein the nominal pressure of cold-producing medium is determined based on the temperature measured, and nominal pressure scope includes the force value of at most deviation one predetermined tolerance of nominal pressure.

8. method according to claim 7, it is characterised in that measure the refrigerant temperature in refrigerant loop (46) at evaporator (18) place.

9. according to the method one of in claim 7 to 8, it is characterised in that measure the temperature outside refrigerant loop (46).

10. according to the method one of in claim 7 to 9, it is characterised in that in order to determine nominal pressure, measured refrigerant temperature improves 5 DEG C, or the measurement temperature outside refrigerant loop (46) improves 15 DEG C.

11. according to the method one of in claim 7 to 10, it is characterized in that, nominal pressure is the evaporating pressure of cold-producing medium, or the cold-producing medium evaporating pressure of the extrapolation that nominal pressure is the critical point (PC) exceeding cold-producing medium, wherein in order to set up nominal pressure, the temperature surveyed improves the value of regulation.

12. according to the method one of in claim 7 to 11, it is characterised in that if pressure lower than nominal pressure more than 10%, then it represents that have deficiency.

13. according to the method one of in claim 7 to 12, it is characterised in that this cold-producing medium is CO₂��

14. according to the method one of in claim 7 to 13, it is characterised in that once there is deficiency, this refrigerant loop (46) is filled via valve cell (24) by the cold-producing medium being stored in storage container (22).

15. method according to claim 14, it is characterised in that this refrigerant loop (46) is filled when compressor (12) is opened at least in part.

16. according to the method one of in claim 14 to 15, it is characterized in that, this refrigerant loop (46) is filled when compressor (12) is opened, and open valve cell (24), until the pressure recorded is within the scope of nominal pressure, wherein nominal pressure scope includes the force value that the maximum deviation with nominal pressure is +/-10%.

17. according to the method one of in claim 14 to 16, it is characterised in that this storage container (22) of storage cold-producing medium is connected to refrigerant loop (46) on the suction side (20) of compressor (12).

18. according to the method one of in claim 14 to 17, it is characterised in that the temperature of this storage container (22) is regulated by heater (48).

19. the device of the refrigerant charge in the refrigerant loop (46) of the refrigeration system (10) of monitoring vehicle, this refrigeration system (10) has the storage container (22) of compressor (12), condenser or gas cooler (14), expansion gear (16), evaporator (18), storage cold-producing medium, and cold-producing medium, particularly CO₂, it runs within the scope of Trans-critical cycle according to operating point, wherein

At least one refrigerant temperature sensors (32) and at least one refrigerant pressure sensor (34) are provided, for measuring the temperature and pressure of cold-producing medium, wherein the temperature and pressure of cold-producing medium can be estimated by this way in control unit (30), thus refrigerant charge error is detectable, and if be detected that not enough, control unit (30) is got involved by the control on refrigerant loop (46) and causes filling

It is characterized in that

Storage container (22) includes heater (48).

20. device according to claim 19, it is characterised in that refrigeration system (10) includes the valve cell (24) with electromagnetic valve and check-valves.