Vehicle cooling circuit

Abstract

The present disclosure relates to a vehicle cooling circuit for cooling a temperature-increasing device, in particular a battery, by means of a coolant conducted in a coolant circuit, wherein the coolant circuit has a heat exchanger configured as an evaporator via which the coolant circuit is coupled to a cooling medium circuit. In accordance with the present disclosure, the chiller is arranged downstream of the heat exchanger in the direction of flow of the coolant in the coolant circuit. Furthermore a bypass valve is arranged in the coolant line such that the coolant can be conducted fully or partially past the chiller.

Claims

1. A system for a vehicle, comprising: a vehicle cooling circuit for cooling a temperature-increasing device via a coolant conducted in a coolant circuit, wherein the coolant circuit includes a coolant line, at least one chiller, a coolant pump, and at least one heat exchanger configured as an evaporator coupling the coolant circuit to a cooling medium circuit including a cooling medium line, at least one compressor, at least one condenser, and at least one relief valve, wherein the at least one chiller is arranged downstream of the at least one heat exchanger in a direction of flow of the coolant in the coolant circuit, wherein a heat exchanger bypass valve is arranged in the coolant line such that the coolant can be fully or partially conducted past the heat exchanger, and wherein at least one chiller bypass valve is arranged in the coolant line such that the coolant is conducted fully or partially past the at least one chiller; and a controller including executable instructions stored in non-transitory memory to: determine an environmental temperature; determine a required temperature at a coolant inlet of the temperature-increasing device; and if the environmental temperature is higher than the required temperature, open the at least one chiller bypass valve and close the heat exchanger bypass valve.

2. The system in accordance with claim 1, wherein both the chiller and the condenser are associated with a cooling air flow, and wherein the temperature-increasing device is a battery.

3. The system in accordance with claim 2, wherein the cooling air flow is generated by a fan.

4. The system in accordance with claim 2, wherein the chiller is arranged in front of the condenser in the cooling air flow.

5. The system in accordance with claim 2, wherein the chiller is arranged after the condenser in the cooling air flow.

6. The system in accordance with claim 1, wherein a liquid coolant container for receiving coolant is integrated in the coolant line.

7. The system in accordance with claim 6, wherein a heater is integrated in the liquid coolant container.

8. The system in accordance with claim 3, wherein the fan has an adjustable speed for setting the cooling air flow.

9. A rail vehicle, comprising: a vehicle coolant circuit for cooling a temperature-increasing device including a battery via a coolant, the coolant circuit comprising: a coolant line; a liquid coolant container; at least one chiller; a coolant pump; at least one chiller bypass valve configured such that the coolant is conducted past the at least one chiller; at least one heat exchanger configured as an evaporator coupling the coolant circuit to a cooling medium circuit, the at least one chiller arranged downstream of the at least one heat exchanger in a direction of flow of the coolant in the coolant circuit; and a heat exchanger bypass valve configured such that coolant is conducted past the at least one heat exchanger; the cooling medium circuit comprising: a cooling medium line; at least one compressor; at least one condenser arranged in front of the at least one chiller of the coolant circuit in a cooling air flow; and at least one relief valve; and a controller including executable instructions stored in non-transitory memory to: determine an environmental temperature and a required temperature at a coolant inlet of the battery; and if the environmental temperature is higher than the required temperature, switch on the at least one compressor, close the heat exchanger bypass valve, and open the at least one chiller bypass valve.

10. The rail vehicle in accordance with claim 9, wherein the cooling air flow is generated by an adjustable speed fan.

11. The rail vehicle in accordance with claim 9, wherein a heater is integrated in the liquid coolant container.

12. The system in accordance with claim 1, wherein the heat exchanger bypass valve is arranged upstream of the at least one chiller bypass valve in the direction of flow of the coolant in the coolant circuit.

13. The rail vehicle in accordance with claim 9, wherein the heat exchanger bypass valve is arranged upstream of the at least one chiller bypass valve in the direction of flow of the coolant in the coolant circuit.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) FIG. 1 shows a vehicle cooling circuit of the prior art such as is known from U.S. Pat. No. 4,415,847 A.

(2) FIG. 2 shows a vehicle cooling circuit such is known from the prior art in accordance with EP 1 266 779 B1.

(3) FIG. 3 shows a first embodiment of a vehicle cooling circuit in accordance with the present disclosure.

(4) FIG. 4 shows a second embodiment of a vehicle cooling circuit in accordance with the present disclosure.

(5) FIG. 5 shows a third embodiment of a vehicle cooling circuit in accordance with the present disclosure.

(6) FIG. 6 schematically illustrates a method of operating a vehicle cooling circuit in accordance with the present disclosure.

DETAILED DESCRIPTION

(7) The coolant circuit 10 in accordance with the present disclosure in accordance with the first embodiment such as is shown in FIG. 3 is coupled to a cooling medium circuit 12 via a heat exchanger 14 configured as an evaporator. The coolant circuit has a coolant line 16 in which the coolant is conveyed via a pump 20 in the direction of the arrow in accordance with FIG. 3. A temperature-increasing device such as a battery 18 of an electric vehicle 100 is cooled via the coolant. Electric vehicle 100 may include an automobile, rail vehicle, or another electrically powered vehicle. A chiller 34 is furthermore provided which is cooled by means of a cooling air flow which is cooled via the airstream of the vehicle and/or via a fan 30. A further cooling of the coolant circuit takes place via the heat exchanger 14 which is configured as an evaporator of the cooling medium circuit 12 thereby coupling the cooling medium circuit to the coolant circuit. The cooling medium circuit 12 comprises a heat exchanger 14 configured as an evaporator, a cooling medium line 22, a compressor 24, a condenser 26 and a relief valve 28. The aforesaid term “evaporator” is used in the connection shown here beyond the actual meaning of the word. If, for example, carbon dioxide is used as a coolant, the “condenser” 26 of the cooling medium circuit 12 acts as a “gas chiller”.

(8) As can be seen from FIG. 3, the chiller 34 is arranged, viewed in the direction of flow of the coolant in the coolant circuit (cf. the direction of the arrow), downstream of the heat exchanger 14. Furthermore, a chiller bypass valve 36 is arranged in the coolant line 16 such that the coolant can be conducted fully or partially past the chiller 34.

(9) In the embodiment in accordance with FIG. 3, the condenser 26 is arranged in front of the chiller 34 in the air flow which is generated, for example, by the fan 30. A greater temperature difference at the chiller can hereby be generated. This increases the possible capacity of the “cold dissipation” at the chiller 34 due to an active cooling medium circuit 12.

(10) The embodiment in accordance with FIG. 4 corresponds to the embodiment in accordance with FIG. 3. In the embodiment of FIG. 4 the chiller 34 is arranged in front of the condenser 26 in the air flow generated by the fan 30. Thus, a smaller temperature differential and a smaller capacity of “cold dissipation” results at the chiller 34 due to an active cooling medium circuit 12. On the other hand, there is the possibility at very high environmental temperatures to lower the condensation temperature by active cooling of the air flow to the condenser 26 using the chiller 34 to ensure the functionality of the vehicle cooling circuit for a comparatively longer time at high environmental temperatures. The system architecture shown here opens up the possibility of regulating the condensation temperature in the cooling medium circuit 12.

(11) Finally, a third embodiment of the vehicle coolant circuit in accordance with the present disclosure is illustrated in FIG. 5. The design substantially corresponds to that in accordance with FIG. 3. However, an evaporator bypass valve 38 is provided which is arranged in the coolant line 16 such that the coolant can be conducted fully or partly past the heat exchanger 14. A further possibility of part-load regulation is opened up by this evaporator bypass valve 38 in which the heat exchanger 14 configured as an evaporator can be bypassed.

(12) In addition, a liquid coolant container 40 can be provided in which the coolant can be temperature controlled to a desired temperature level via an electrically operated resistance heater 42.

(13) Different operating modes can be run with the vehicle coolant circuit in accordance with the present disclosure. FIG. 6 illustrates a method 600 of operating a vehicle cooling system in accordance with an embodiment of the present disclosure. Method 600 may be performed by the controller 138, sensors 140, and actuators 142 illustrated in FIGS. 3-5. For example, sensors 140 may provide temperature information such as coolant inlet temperature and environmental temperature, for example. Controller 138 may compare the temperature information to an associated threshold and change the operating mode of the vehicle cooling system through actuators 142. Actuators 142 may be configured to change a position of one or more valves and/or bypass valves of the vehicle coolant circuit, change a speed of a fan, start or stop one or more of the coolant pumps or cooling medium compressors, or any other feature of the vehicle coolant circuit.

(14) Returning to FIG. 6, at 602, method 600 includes determining a coolant inlet temperature. The coolant inlet temperature may be determined by a temperature sensor at the coolant inlet of a battery of the vehicle, for example. It will be appreciated that the coolant inlet temperature may be determined continuously to insure coolant inlet temperature is maintained at the required threshold temperature.

(15) At 604, method 600 includes comparing the coolant inlet temperature to a threshold. If the coolant inlet temperature is greater than the threshold, then the cooling medium circuit is activated at 606. If the coolant inlet temperature is not greater than the threshold, then method 600 continues to 608.

(16) At 608, method 600 includes comparing the coolant inlet temperature to the threshold. If the coolant inlet temperature is less than the threshold, then the cooling medium system is deactivated at 610.

(17) Specific operating modes of the coolant circuit and cooling medium circuit of the vehicle cooling circuit associated with method 600 will now be described with reference to the embodiments illustrated in FIGS. 3-5. In accordance with a first operating mode, in which the environmental temperature is higher than the required coolant inlet temperature into the battery 18, the cooling medium circuit 12 is active. This means that the compressor 24 is switched on and that in the embodiment variant in accordance with FIG. 5 the evaporator bypass valve 38 opens the path through the heat exchanger 14 configured as an evaporator, with the evaporator bypass being closed. The chiller bypass valve 36 opens the chiller bypass and closes the path to the chiller 34.

(18) If the cooling medium circuit 12 has a coolant inlet temperature lower than that required at the outlet from the heat exchanger 14, the temperature of the coolant can be increased by partial opening of the evaporator bypass valve 38. The maximum permitted degree of opening of the evaporator bypass valve 38 depends on the operating point of the cooling medium circuit and on the compressor 24 used. If the required coolant inlet temperature is still higher than the provided coolant temperature, the inflow to the chiller 34 can be opened by a step-wise opening of the chiller bypass valve 36, with the chiller bypass line simultaneously increasingly being closed in a step-wise manner. The temperature of the coolant now partially conducted via the chiller 34 can hereby be further increased up to the required coolant inlet temperature.

(19) If the coolant circuit delivers a coolant inlet temperature higher than that required, the coolant temperature can again be lowered to the minimally possible temperature by reversing the above-named steps, with a minimal temperature being achieved here in that the compressor 24 is switched on, in that the coolant is conducted completely via the heat exchanger 14, and in that the largely cooled coolant is not conducted via the chiller 34.

(20) In the event that the environmental temperature is lower than the required coolant inlet temperature into the battery, the transferred cooling power may be sufficient at the chiller under certain circumstances to lower the temperature of the coolant below the required coolant inlet temperature. In this case, the cooling medium circuit 12 does not have to be activated. The compressor 24 can remain switched off and the evaporator bypass valve conducts the coolant past the heat exchanger 14 configured as an evaporator. The chiller bypass valve 36 is connected such that the total cooling medium flow is conducted via the chiller 34. If the cooling circuit continues to deliver a coolant inlet temperature lower than that required at the battery 18, the temperature of the coolant can be further increased up to the required coolant inlet temperature by a step-wise opening of the chiller bypass valve 36.

(21) If the environmental temperature is admittedly lower than the required coolant inlet temperature into the battery, but the transferred cooling power at the chiller 34 is not sufficient to cool the coolant to the required coolant inlet temperature at the inlet of the battery, the cooling medium circuit 12 is instead activated in that the compressor 24 is switched on. The evaporator bypass valve 38 is simultaneously connected such that the coolant is conducted via the heat exchanger 14 configured as an evaporator. The part-load regulation then takes place in accordance with the initially explained operating mode.

(22) In a further operating mode, the functionality can be ensured at very high external temperatures using the embodiment variant of the vehicle coolant circuit shown in FIG. 4. In this embodiment variant, the condenser 26 is arranged in the air flow after the chiller 34. Unlike the circuit in accordance with EP 1 266 779 B1, the possibility results here of actively cooling the air flow to the condenser 26 using chiller 34.

(23) It must be stated for explanation in this respect that the required coolant inlet temperature can no longer be reached from a defined outside temperature onward (for example 45° C.). On the other hand, there is the demand that the cooling medium circuit remains functional up to a maximum outside temperature (of 55° C., for example).

(24) If no possibility—of any form whatsoever—is provided for power reduction in the cooling medium circuit, the cooling medium circuit has to be configured such that it can also be operated at defined maximum temperatures at full-load operation. This means that a larger condenser 26 or an increased air flow through the condenser 26 is necessary.

(25) It is, however, possible in the system architecture in accordance with FIG. 4 to lower the condensation pressure which is a limiting parameter for the functionality of the vehicle cooling circuit at high environmental temperatures. For this purpose, some of the chilling power which is introduced into the cooling circuit at the heat exchanger 14 is used at the chiller to lower the temperature of the air flow at the condenser inlet and thus also the condensation temperature (corresponds to the condensation pressure) for the heat dissipation. The chiller bypass valve 36 opens the path through the chiller 34 step-wise and closes the bypass line.

(26) The integration of a liquid coolant container 40 for receiving coolant into the cooling circuit is shown by way of example with reference to the embodiment in accordance with FIG. 5. This embodiment variant can also be provided in the embodiments in accordance with FIG. 3 or 4. This additional liquid coolant container 40 can likewise be dispensed with in the embodiment in accordance with FIG. 5.

(27) The integration of the electrically operated resistance heater 42 in the liquid container is likewise only selectively provided. The coolant inlet temperature can, for example, be kept at a minimal temperature and also increased again as necessary via this heating.

(28) In accordance with a further embodiment, the speed of fan 30 may be adjustable or include variable speed settings to vary the air speed and/or quantity of the cooling air flow.

(29) The control methods and routines disclosed herein may be stored as executable instructions in non-transitory memory of the controller and carried out by the controller in combination with the various structural system elements, such as actuators, valves, etc. The specific routines described herein may represent one or more of any number of processing strategies such as event-driven, interrupt-driven, multi-tasking, multi-threading, and the like. As such, various actions, operations, and/or functions illustrated may be performed in the sequence illustrated, in parallel, or in some cases omitted. Likewise, the order of processing is not necessarily required to achieve the features and advantages of the example embodiments described herein, but is provided for ease of illustration and description. One or more of the illustrated actions, operations and/or functions may be repeatedly performed depending on the particular strategy being used. Further, the described actions, operations and/or functions may graphically represent code to be programmed into non-transitory memory of the computer readable storage medium in the engine control system carried out in combination with the described elements of the structural system.

(30) It will be appreciated that the configurations and routines disclosed herein are exemplary in nature, and that these specific embodiments are not to be considered in a limiting sense, because numerous variations are possible.