COOLING SYSTEM

Abstract

The invention relates to a cooling system (1) for a vehicle. The cooling system (1) comprises a cooling circuit (2) having a first and second heat source (3a, 3b) and a first and second radiator (4a, 4b). In the cooling circuit (2), the heat sources (3a, 3b) and the radiator (4a, 4b) are connected in series with one another. A hydraulic switch (6) divides the cooling circuit (2) into two partial circuits (2a, 2b). The respective partial circuit (2a, 2b) each includes the respective heat sources (3a, 3b) and the respective radiator (4a, 4b).

The invention also relates to a method for operating the cooling system (1).

Claims

1. A cooling system (1) for a vehicle, in particular for a utility vehicle, wherein the cooling system (1) comprises a cooling circuit (2) that can be flowed through by a coolant, wherein the cooling circuit (2) comprises a first heat source (3a) to be cooled at a lower temperature level, a first radiator (4a), a second heat source (3b) that can be cooled at a higher temperature level and a second radiator (4b), characterised in that in the cooling circuit (2) the first heat source (3a), the first radiator (4a), the second heat source (3b) and the second radiator (4b) are connected in series with one another, and in that the cooling circuit (2) comprises a hydraulic switch (6), which divides the cooling circuit (2) into a first partial circuit (2a) with the first heat source (3a) and the first radiator (4a) and into a second partial circuit (2b) with the second heat source (3b) and the second radiator (4b).

2. The cooling system according to claim 1, characterised in that a first pump (5a) in the first partial circuit (2a) is connected in series with the first heat source (3a) and with the first radiator (4a) and a second pump (5b) in the second partial circuit (2b) is connected in series with the second heat source (3b) and with the second radiator (4b).

3. The cooling system according to claim 2, characterised in that the first partial circuit (2a) is fluidically connected to the hydraulic switch (6) via a first inlet leading into the switch (6) and a first outlet leading out of the switch (6) and the second partial circuit (2b) is fluidically connected to the hydraulic switch (6) via a second inlet leading into the switch (6) and a second outlet leading out of the switch (6), and in that the flow and the mixing of the coolant in the hydraulic switch (6) takes place dependent on the adjusted pump pressure and/or on the adjusted rotational speed and/or on the adjusted mass flow of the two pumps (5a, 5b).

4. The cooling system according to claim 2 or 3, characterised in that the two pumps (5a, 5b) and lines leading to the pumps (5a, 5b) are combined into a module (14) and/or in that the two pumps (5a, 5b) are realised by a double pump having a common shaft and a magnetic coupling for adjusting different rotational speeds in the two pumps (5a, 5b), and/or in that the two pumps (5a, 5b) are each realised by a pump with a viscous coupling and can be operated with a common motor, and/or in that the two pumps (5a, 5b) each comprise an adjustable impeller geometry for variably adjusting the mass flow of the coolant.

5. The cooling system according to any one of the preceding claims, characterised in that the first partial circuit (2a) comprises a warming-up bypass line (7) connected in parallel with the first heat source (3a) and a warming-up bypass valve (8) preferentially a switching valve or a regulating valve or a thermostat valve, wherein the warming-up bypass line (7) can be closed and opened by means of the warming-up bypass valve (8), and/or in that the second partial circuit (2b) comprises a radiator bypass line (9) connected in parallel with the second radiator (4b) for flowing about the second radiator (4b) and a radiator bypass valve (10), wherein the radiator bypass line (9) can be closed and opened by means of the radiator bypass valve (10), and/or in that the second partial circuit (2b) comprises a heat source bypass line (11) connected in parallel with the second heat source (3b) for flowing about the second heat source (3b) and a heat source bypass shut-off valve (12), wherein the heat source bypass line (11) can be closed and opened by means of the heat source bypass shut-off valve (12).

6. The cooling system according to any one of the preceding claims, characterised in that the first radiator (4a) with respect to an air flow direction is connected upstream of the second radiator (4b), and/or in that the first radiator (4a) and the second radiator (4b) partially or completely overlap one another with respect to an air flow direction.

7. A method for operating the cooling system (1) according to any one of the preceding claims, wherein a first pump (5a) in the first partial circuit (2a) and a second pump (5b) in the second partial circuit (2b) are connected in series and wherein the cooling system (1) can be operated in a braking mode and/or in a normal operating mode and/or in a warming-up mode.

8. The method according to claim 7, characterised in that the cooling system (1) is operated in the braking mode, wherein in the braking mode: the first pump (5a) and the second pump (5b) are switched on; the flow and the mixing of the coolant in the hydraulic switch (6) is regulated dependent on the adjusted pump pressure and/or on the adjusted rotational speed and/or on the adjusted mass flow of the two pumps (5a, 5b), so that in the hydraulic switch (6) the coolant flows from a first inlet to a first outlet and from a second inlet to a second outlet, in that the first partial circuit (2a) and a second partial circuit (2b) are almost completely separated hydraulically and the first partial circuit (2a) is flowed through by a first part of the coolant and a second cooling circuit (2b) by a second part of the coolant.

9. The method according to claim 7, characterised in that the cooling system is operated in the braking mode, wherein in the braking mode: the temperature of the coolant upstream of the first heat source (3a) is co-influenced by a delivery rate of the first pump (5a), and an overheating of the first heat source (3a) is avoided by a lowering of the delivery rate of the second pump (5b).

10. The method according to claim 7, characterised in that the cooling system (1) is operated in the normal operating mode, wherein in the normal operating mode with a high cooling capacity requirement: the first pump (5a) and the second pump (5b) are switched on and the second heat source (3b) is switched off; the flow and the mixing of the coolant in the hydraulic switch (6) is regulated dependent on the adjusted pump pressure and/or on the adjusted rotational speed and/or on the adjusted mass flow of the two pumps (5a, 5b), so that in the hydraulic switch (6) the coolant flows from the first inlet to the second outlet and from the second inlet to the second outlet, and so that the first partial circuit (2a) and the second partial circuit (2b) are almost completely connected hydraulically and the first partial circuit (2a) and the second cooling circuit (2b) are flowed through by a common part of the coolant.

11. The method according to claim 7, characterised in that the cooling system (1) is operated in the normal operating mode, wherein in normal operating mode with a high cooling capacity requirement: the first pump (5a) is switched on and the second heat source (3b) and the second pump (5b) are switched off; the flow and the mixing of the coolant in the hydraulic switch (6) is regulated dependent on the adjusted pump pressure and/or on the adjusted rotational speed and/or on the adjusted mass flow of the pump (5a), so that in the hydraulic switch (6) the coolant flows almost completely from the first inlet to the first outlet and almost completely from the second inlet to the second outlet, and in that the first partial circuit (2a) and the second partial circuit (2b) are almost completely separated hydraulically, wherein the first partial circuit (2a) is flowed through by a first part of the coolant and there is almost no flow by a second part of the coolant through the second partial circuit (2b).

12. The method according to any one of the claims 7 to 11, characterised in that in the normal operating mode or in the braking mode the second radiator (4b) is flowed through or bypassed by a radiator bypass line (9); in that in the normal operating mode the second heat source (3b) is flowed through or bypassed via a heat source bypass line (11).

13. The method according to claim 7, characterised in that the cooling system is operated in the warming-up mode, wherein in the warming-up mode: the first pump (5a) is switched on and the second pump (5b) is switched off; the second partial circuit (2a) and the first radiator (4a) are separated from the first heat source (3a) by means of a warming-up bypass valve (8) and are not flowed through; the first heat source (3a) and a warming-up bypass line (7) connected in parallel with the heat source (3a) are flowed through.

Description

[0029] Preferred exemplary embodiments of the invention are shown in the drawings and are explained in more detail in the following description.

[0030] The only FIG. 1 shows a circuit diagram of a cooling system 1 according to the invention. Here, the cooling system 1 comprises a cooling circuit 2 with a first partial circuit 2a and with a second partial circuit 2b. In the cooling circuit 2, a first heat source 3a, a second heat source 3b, a first radiator 4a and a second radiator 4b are connected in series with one another. Here, the two partial circuits 2a and 2b are separated from one another by means of a hydraulic switch 6. In the first partial circuit 2a, the first heat source 3a and the first radiator 4a and in the second partial circuit 2b, the second heat source 3b and the first radiator 4b are connected in series with one another.

[0031] The cooling system 1 is provided for a vehicle, in particular for a utility vehicle. The first heat source 3a can be in particular a fuel cell and a second heat source 3b can be in particular a retarder. The first radiator 4a and the second radiator 4b can be coolant-air-radiators. The coolant is preferentially a liquid.

[0032] The cooling circuit 2 comprises a first pump 5a and a second pump 5b. In the first partial circuit 2a, the first pump 5a is directly connected downstream of the first heat source 3a. The term “directly” in this context means that the pump 5a and the respective heat source 3a are connected on a common flow line between two adjacent branch nodes. In the second partial circuit 2b, the second pump 5b is connected upstream of the second heat source 3a.

[0033] Further, the first partial circuit 2a comprises a warming-up bypass line 7 and a warming-up bypass valve 8. The warming-up bypass line 7 is connected in parallel with the first heat source 3a. When the warming-up bypass line 7 is opened by means of the warming-up bypass valve 8, the remaining radiator circuit 2 is fluidically separated from the first heat source 3a and only the first heat source 3a and the warming-up bypass line 7 can be flowed through. When the warming-up bypass line 7 is closed by means of the warming-up bypass valve 8, the entire cooling circuit 2 can be flowed through and the warming-up bypass line 7 cannot be flowed through.

[0034] The second partial circuit 2b comprises a radiator bypass line 9 and a radiator bypass valve 10. The radiator bypass line 9 is connected in parallel with the second radiator 4b. When the radiator bypass line 9 is opened by means of the radiator bypass valve 10, the second radiator 4b is bypassed.

[0035] When the radiator bypass line 9 is closed by means of the radiator bypass valve 10, the second radiator 4b is flowed through and the coolant cooled.

[0036] In addition, the second partial circuit 2b comprises a heat source bypass line 11 and a heat source bypass shut-off valve 12. The heat source bypass linell is connected parallel with the second heat source 3b and the heat source bypass shut-off valve 12 is arranged in the heat source bypass line 11. When the heat source bypass line 11 is opened, the second heat source 3a can be bypassed. When the heat source bypass line 11 is closed, the second heat source 3b can be flowed through or not bypassed.

[0037] The two radiators 4a and 4b can be flowed through by air in an air flow direction SR. Here, the first radiator 4a and the second radiator 4b can completely or partially overlap one another in the air flow direction SR, wherein the first radiator 4a is connected upstream of the second radiator 4b with respect to the air flow direction SR. Behind the radiators 4a and 4b, one or more blowers 13 are arranged, which can intensify the flow of air through the radiators 4a and 4b.

[0038] In this exemplary embodiment, the two pumps 5a and 5b and the hydraulic switch 6 are combined in a common module 14—as indicated by broken lines. Basically, however, the two pumps 5a and 5b and the hydraulic switch 6 can be installed separately from one another. Here, the module 14 includes five liquid connections which lead to the first heat source 3a, to the second heat source 3b, to the warming-up bypass line 7, to the first radiator 4a and to the second radiator 4b.

[0039] Regardless of the embodiment, the cooling system 1 can be operated by means of a method according to the invention in a braking mode and/or in a normal operating mode and/or in a warming-up mode.

[0040] In the braking mode, the two heat sources 3a and 3b and the two pumps 5a and 5b are switched on. By way of the two switched-on pumps 5a and 5b and the hydraulic switch 6, the two partial circuits 2a and 2b are hydraulically separated from one another almost completely. A mixing of the coolant in the hydraulic switch 6 however continues to take place. The two partial circuits 2a and 2b are thus flowed through by parts of the coolant that are almost completely separated from one another. Starting out from a mean temperature level in the hydraulic switch 6, the coolant is suctioned through the first radiator 4a with the first pump 5a. In the first radiator 4a, the coolant is cooled and then flows through the first heat source 3a. In the braking mode, the two heat sources 3a and 3b can be suitably cooled at differing temperature levels. Accordingly, the first heat source 3a can be cooled at a lower temperature level and the second heat source 3b at a higher temperature level. Because of this, an overheating of the first heat source 3a can be prevented and the cooling capacity on the second heat source 3b increased.

[0041] In the normal operating mode, the first heat source 3a is switched on and the second heat source 3b switched off. Accordingly, exclusively the first heat source 3a has to be cooled. With a low cooling capacity requirement, the first pump 5a is switched on and the second pump 5b switched off in this case. The first pump 5a is then regulated so that the two partial circuits 2a and 2b are almost completely separated from one another hydraulically. However, a mixing of the coolant in the hydraulic switch 6 continues to take place. Here, the first partial circuit 2a is flowed through and—since the second pump 5b is switched off—there is almost no flow through the second partial circuit 2b. The cooling of the first heat source 3a is solely assumed by the first radiator 4a.

[0042] With a high cooling capacity requirement, the two pumps 5a and 5b are switched on in the normal operating mode. Here, the pumps 5a and 5b are regulated so that partial circuits 2a and 2b or the entire cooling circuit 2 are flowed through by a common part of the coolant. However, a mixing of the coolant in the hydraulic switch 6 continues to take place. Here, the two radiators 4a and 4b are flowed through by the coolant in series and the first heat source 3a is cooled by the two radiators 4a and 4b. In the process, the second heat source 3b can be flowed through or bypassed by way of the heat source bypass line 11. The second radiator 4b can be flowed through or at least partially bypassed by way of the radiator bypass line 9.

[0043] In the warming-up mode, the warming-up bypass valve 8 is switched so that exclusively the first heat source 3a, the first pump 5a and the warming-up bypass line 7 are flowed through. Here, the second heat source 3b can be flowed through or bypassed via the heat source bypass line 11. The second radiator 4b can also be flowed through or bypassed via the radiator bypass line 9. In the warming-up mode, a reduced thermal mass flows through the first heat source 3a and the coolant can be rapidly heated.