DE102019121666B3 - Method for cooling components with a cooling circuit with several evaporators - Google Patents

Abstract

A method for cooling components, in particular components of a motor vehicle, is proposed, whereby a coolant along a cooling circuit (100) from a compressor (8) to a first expansion valve (1) which is located in the cooling circuit (100) upstream of a first evaporator ( 3) a first component is arranged, pumped and evaporated in the first evaporator (3), the coolant along the cooling circuit (100) further from the compressor (8) to a second expansion valve (2), which in the cooling circuit (100) a second evaporator (4) of a second component is arranged, pumped and evaporated in the second evaporator (4), the first expansion valve (1) being opened so wide that a first mass flow of the coolant to achieve a first cooling capacity in the first evaporator (3) flows, wherein a second mass flow of the coolant to achieve a second cooling capacity in the second evaporator (4) is calculated, the Verd ichter (8) is set to provide the first mass flow and the second mass flow, the second expansion valve (2) being opened so far that the second mass flow flows into the second evaporator (4).

Description

The present invention relates to a method for cooling components, in particular components of a motor vehicle, with a cooling circuit, the cooling circuit having a plurality of evaporators.

Usually, the regulation of a cooling circuit with several evaporators takes place via a regulation of the compressor. Since a controller can only be set to one value, the cooling circuit is regulated in such a way that one evaporator is operated with a setpoint value, while the other evaporators are operated blindly. Alternatively, and common practice, it is that the compressor is set so that all evaporators operate in an acceptable range.

From the DE 10 2009 015 653 A1 It is known to provide a battery heat exchanger for setting the temperature and to selectively control the refrigerant flow through the battery heat exchanger by means of a battery cooling shut-off valve.

The DE 698 33 266 T describes refrigeration systems for the most diverse areas of application, whereby it is essential that the compressor modulates the performance of the system in a targeted manner based on the control signals.

It is an object of the present invention to provide a method for cooling components, in particular components of a motor vehicle, with a cooling circuit, the multiple evaporators of the cooling circuit being able to be controlled independently of one another and thus improving the efficiency of the cooling circuit.

This object is achieved by a method for cooling components, in particular components of a motor vehicle, wherein a coolant is pumped along a cooling circuit from a compressor to a first expansion valve, which is arranged in the cooling circuit upstream of a first evaporator of a first component, and in the first evaporator is evaporated, the coolant along the cooling circuit further from the compressor to a second, which is arranged in the cooling circuit upstream of a second evaporator of a second component, is pumped and evaporated in the second evaporator, the first expansion valve is opened so far that a first Mass flow of the coolant flows into the first evaporator to achieve a first cooling capacity, a second mass flow of the coolant being calculated to achieve a second cooling capacity in the second evaporator, the compressor for providing the first mass flow and the second mass flow omes is set, wherein the second expansion valve is opened so far that the second mass flow flows into the second evaporator.

The method according to the invention makes it possible to regulate the cooling in an energy-optimal way by setting the first expansion valve and the second expansion valve. For this purpose, the mass flows of the coolant are controlled in direct dependence on the required cooling capacity. It is conceivable that the first cooling capacity is measured and / or determined from an expected cooling capacity of the first component. It is also conceivable that the second cooling capacity is measured and / or determined from an expected cooling capacity of the second component. The first expansion valve is preferably arranged directly in front of the first evaporator. The second expansion valve is preferably arranged directly in front of the second evaporator. In the context of the present invention, direct means that no other components are arranged between the first expansion valve and the first evaporator or between the second expansion valve and the second evaporator apart from components for guiding the coolant, such as coolant lines or coolant hoses. The coolant is preferably a fluidic coolant. Arranged in the coolant circuit in front of or behind a component relates in the sense of the present invention to the flow direction of the coolant.

It is conceivable that the method is carried out and adapted accordingly with a cooling circuit which has more than two evaporators.

Advantageous embodiments and developments of the invention can be found in the subclaims and in the description with reference to the drawings.

According to a preferred embodiment of the invention it is provided that the pressure and temperature of the coolant are measured by sensor units arranged upstream and downstream of the compressor in a flow direction of the coolant and by sensor units arranged upstream of the first expansion valve and upstream of the second expansion valve, with the aid of measurement data from the sensor units the first mass flow and the second mass flow can be determined. This enables the mass flows to be fully recorded and thus optimal control of the cooling.

According to a further preferred embodiment of the invention it is provided that a suction pressure regulator arranged downstream of the first evaporator in the direction of flow of the coolant Pressure of the coolant downstream of the first evaporator is regulated so that the first evaporator does not freeze and / or the pressure of the coolant downstream of the second evaporator is regulated by a further suction pressure regulator arranged in the flow direction of the coolant downstream of the second evaporator so that the second evaporator does not icy. This enables the cooling to function reliably by avoiding icing. It is conceivable that the suction pressure regulators are valves. It is also conceivable that the suction pressure regulators are gradually openable valves.

According to a further preferred embodiment of the invention it is provided that the coolant is liquefied by a condenser arranged downstream of the compressor and upstream of the first expansion valve and upstream of the second expansion valve. This advantageously makes it possible to provide the coolant in the liquid phase at the expansion valves.

According to a further preferred embodiment of the invention it is provided that a speed of the compressor is increased or decreased in order to provide the first mass flow and the second mass flow. By adapting the speed of the compressor, the compression is adapted to a changed mass flow.

According to a further preferred embodiment of the invention it is provided that after the calculation of the second mass flow, a check is made as to whether the speed can be increased so that the first mass flow and the second mass flow can be provided, wherein it is preferably also checked whether the coolant is after Adjusting the first mass flow and the second mass flow can be liquefied by the condenser. This makes it possible to carry out the method according to the invention within the given technical limits. Should it not be possible to provide a speed and / or a suitable liquefaction, it is conceivable that the first component and / or the second component are regulated in such a way that the first cooling capacity or the second cooling capacity are reduced.

According to a further preferred embodiment of the invention, it is provided that an electrical expansion valve is used as the first expansion valve and / or as the second expansion valve, a stepper motor-controlled electrical expansion valve being preferably used in each case. This allows the mass flows to be set very precisely.

According to a further preferred embodiment of the invention, it is provided that the coolant flows out of the first evaporator with a first overheating and / or the coolant flows out of the second evaporator with a further overheating. This ensures that the refrigerant is completely evaporated in the evaporators, which increases the efficiency of the cooling. It is conceivable that the coolant is pumped with a first subcooling to the first expansion valve and / or the coolant is pumped with a second subcooling to the second expansion valve. This ensures that the coolant is in the liquid phase at the expansion valves. It is also conceivable that, for more efficient production of the subcooling, the coolant is passed through a heat exchanger arranged between the condenser and expansion valves to give off heat from the liquid coolant. In addition, it is conceivable that the heat exchanger conducts heat from the liquid coolant to the evaporated coolant. It is conceivable that the heat exchanger conducts heat from the liquid coolant between the condenser and expansion valves to the evaporated coolant between the evaporators and the compressor.

According to a further preferred embodiment of the invention, it is provided that when the first cooling capacity and / or the second cooling capacity change dynamically, the first mass flow or the second mass flow are dynamically adapted and / or the first overheating and the second overheating are adapted dynamically. This always enables optimal cooling with changing requirements.

According to a further preferred embodiment of the invention it is provided that underfilling or overfilling of the cooling circuit with coolant is checked from the determined first mass flow and the determined second mass flow. This advantageously enables the coolant level to be corrected even before problems or failures caused by underfilling or overfilling occur.

• 1 illustriert schematisch einen Kühlkreislauf zur Ausführung eines Verfahrens gemäß einer beispielhaften Ausführungsform der vorliegenden Erfindung.

Further details, features and advantages of the invention emerge from the drawings and from the following description of preferred embodiments with reference to the drawings. The drawings merely illustrate exemplary embodiments of the invention, which do not restrict the concept of the invention.

• 1 schematically illustrates a cooling circuit for carrying out a method according to an exemplary embodiment of the present invention.

In 1 is schematically a cooling circuit 100 illustrated in accordance with an exemplary embodiment of the present invention. The cooling circuit 100 instructs the compressor 8th on, which compresses a fluidic coolant. In the direction of flow F. the coolant to the compressor 8th following is the capacitor 9 arranged, which liquefies the compressed coolant. This is done here by transferring heat from the coolant to another medium, for example air or water. The liquid and cooled coolant is fed to the first expansion valve 1 and to the second expansion valve 2 directed. The expansion valves 1 , 2 are stepper motor controlled electrical expansion valves 1 , 2 and gradually adjustable in flow. To the first expansion valve 1 then the refrigerant goes into the first evaporator 3 and to the second expansion valve 2 then into the second evaporator 4th directed. In the evaporators 3 , 4th the coolant evaporates and absorbs heat. This allows the vaporizer 3 , 4th can be used as cooling devices such as chillers. In particular is the use of the vaporizer 3 , 4th conceivable as a cooling device in motor vehicles.

As a rule, the first evaporator is used 3 and the second evaporator 4th as a cooling device for cooling different components. This typically results in different amounts of heat which have to be cooled with different cooling capacities. About the different cooling capacities on the evaporators 3 , 4th Realize the expansion valves 1 , 2 controlled in such a way that through them a mass flow of coolant tailored to the respective cooling capacity into the evaporator 3 , 4th is initiated. With the help of the immediately before and after the compressor 8th arranged sensor units 5 , 6 and the one after the first evaporator 3 in the return of the cooling circuit 100 arranged sensor unit 7th the pressure and temperature of the coolant are recorded and from this the first mass flow through the first evaporator 3 , the mass flow through the compressor 8th and finally the second mass flow through the second evaporator 4th be determined. It is conceivable that behind the second evaporator 4th a sensor unit for measuring the pressure and temperature of the coolant is also provided. A measurement of pressure and temperature would be behind the second evaporator 4th redundant, but would lead to an improved control of the cooling by reducing the measurement errors. The second mass flow through the second evaporator is based on the second cooling capacity 4th calculated and at the second expansion valve 2 set. So that the first mass flow and the second mass flow can be implemented correctly, the speed of the compressor 8th and the capacitor 9 adjusted accordingly.

The control of the expansion valves 1 , 2 happens dynamically, which means that the mass flows are adapted when the first and / or second cooling capacity changes. It is conceivable that the mass flows are adapted to a cooling capacity that is not yet applied but is to be expected.

To ensure that the coolant completely liquefies the expansion valves 1 , 2 reached, the coolant flows through between the condenser 9 and expansion valves 1 , 2 the heat exchanger 10 . In the heat exchanger 10 the liquid coolant is further cooled down to a temperature below the condensation temperature of the coolant on the upstream side. For this purpose, heat is transferred from the liquid coolant in the supply line to evaporated coolant in the return line of the cooling circuit 100 transfer.

List of reference symbols

1

first expansion valve

2

second expansion valve

3

first evaporator

4th

second evaporator

5, 6, 7

Sensor units

8th

compressor

9

capacitor

10

Heat exchanger

100

Cooling circuit

F.

Flow direction

Claims (10)

Method for cooling components, in particular components of a motor vehicle, wherein a coolant is pumped along a cooling circuit (100) from a compressor (8) to a first expansion valve (1) which is arranged in the cooling circuit (100) upstream of a first evaporator (3) of a first component and is pumped in the first evaporator (3) is vaporized, wherein the coolant along the cooling circuit (100) is further pumped from the compressor (8) to a second expansion valve (2) which is arranged in the cooling circuit (100) upstream of a second evaporator (4) of a second component and in the second evaporator (4 ) is evaporated, wherein the first expansion valve (1) is opened so far that a first mass flow of the coolant flows into the first evaporator (3) to achieve a first cooling capacity, wherein a second mass flow of the coolant is calculated to achieve a second cooling capacity in the second evaporator (4), the compressor (8) being set to provide the first mass flow and the second mass flow, the second expansion valve (2) being opened so far that the second mass flow flows into the second evaporator (4). Procedure according to Claim 1 The pressure and temperature of the coolant are measured by sensor units arranged upstream and downstream of the compressor in a flow direction of the coolant and by sensor units arranged upstream of the first expansion valve and upstream of the second expansion valve, the first mass flow and the second mass flow being determined on the basis of measurement data from the sensor units will. Method according to one of the preceding claims, wherein the pressure of the coolant downstream of the first evaporator is regulated by a suction pressure regulator arranged downstream of the first evaporator in the direction of flow of the coolant so that the first evaporator does not freeze and / or by one downstream of the second in the direction of flow of the coolant Evaporator arranged further suction pressure regulator, the pressure of the coolant downstream of the second evaporator is regulated so that the second evaporator does not ice up. Method according to one of the preceding claims, wherein the coolant is liquefied by a condenser (9) arranged downstream of the compressor (8) and upstream of the first expansion valve (1) and upstream of the second expansion valve (2) in the direction of flow (F). Method according to one of the preceding claims, wherein in order to provide the first mass flow and the second mass flow in an electric compressor, the speed is increased or decreased and, when a mechanical compressor is used, the stroke is variably controlled via a compressor control valve. Procedure according to Claim 5 , after calculating the second mass flow it is checked whether the speed can be increased so that the first mass flow and the second mass flow can be provided, preferably also checking whether the coolant after setting the first mass flow and the second mass flow of the condenser (9) can be liquefied. Method according to one of the preceding claims, wherein an electrical expansion valve is used as the first expansion valve (1) and / or as the second expansion valve (2), a stepper motor-controlled electrical expansion valve being preferably used in each case. Method according to one of the preceding claims, wherein the coolant flows in with a first overheating from the first evaporator (3) and / or the coolant flows in with a second overheating from the second evaporator (4). Procedure according to Claim 8 , with the first mass flow or the second mass flow being dynamically adapted and / or the first overheating or the second overheating being adapted dynamically in the case of a dynamically changing first cooling output and / or the second cooling output. Method according to one of the Claims 2 to 9 , an underfilling or overfilling of the cooling circuit (100) with coolant being checked from the determined first mass flow and the determined second mass flow.

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