Cooling device for cooling a hot heat transfer fluid in a vehicle

Abstract

Cooling device (10) for cooling a hot heat transfer fluid (WF) in a vehicle, comprising a heat transfer channel (20) for guiding a flow of the hot heat transfer fluid (WF) and a cooling channel (30) for guiding a flow of a cooling fluid (KF), wherein the heat transfer channel (20) and the cooling channel (30) are coupled to each other via a cooling section (22) for heat transfer, further comprising an additional cooling channel (40) for guiding a flow of additional coolant (ZF) with an opening section (42) having a plurality of outlet openings (44) for the outlet of the additional coolant (ZF) in droplet form onto an additional cooling section (24) of the heat transfer channel (20) for absorbing heat by evaporation of the additional coolant (ZF).

Description

[0001] The present invention relates to a cooling device for cooling a hot heat transfer fluid in a vehicle and to a method for the additional cooling of a heat transfer fluid with a cooling device according to the invention.

[0002] It is known that heat transfer fluids in vehicles must be cooled. Such a heat transfer fluid can be, for example, the vehicle's engine oil. Other fluids, especially liquids, can also absorb heat in the vehicle and serve as heat transfer fluids. To cool the vehicle or its components, particularly drive components such as the internal combustion engine, known heat transfer fluids are coupled with cooling devices to dissipate the heat from the vehicle.

[0003] Examples of state-of-the-art documents include US 2016 / 0 153 719 A1, US 2008 / 0 184 732 A1, EP 1 811 646 A1, DE 10 2017 210 276 A1 or DE 10 2018 106 534 A1.

[0004] A disadvantage of existing solutions is that the cooling systems are designed for a defined efficiency point. This means that the cooling fluid can absorb a maximum amount of heat from the heat transfer fluid and dissipate it from the vehicle within a defined time period. The greater this heat transfer per unit of time, the larger and therefore more expensive the cooling system must be. However, since extreme temperatures only occur for very short periods during vehicle operation, this necessitates very large cooling systems in existing vehicles. This results in high costs and weight, which is only required in a few specific operating situations, such as under heavy loads during vehicle operation or at correspondingly high ambient temperatures. In most operating situations, the cooling system is therefore oversized.

[0005] The object of the present invention is to at least partially overcome the disadvantages described above. In particular, the object of the present invention is to ensure, in a cost-effective and simple manner, the possibility of efficient cooling even in particularly hot operating conditions.

[0006] The foregoing problem is solved by a cooling device having the features of claim 1 and a method having the features of claim 9. Further features and details of the invention will become apparent from the dependent claims, the description, and the drawings. Features and details described in connection with the cooling device according to the invention naturally also apply in connection with the method according to the invention, and vice versa, so that the disclosure of the individual aspects of the invention always refers, or can refer, to each other.

[0007] According to the invention, a cooling device serves to cool hot heat transfer fluid in a vehicle. For this purpose, the cooling device has a heat transfer channel designed to carry a flow of the hot heat transfer fluid. In addition, the cooling device is equipped with a cooling channel for carrying a flow of cold coolant. The heat transfer channel and the cooling channel are coupled to each other via a heat transfer section. Furthermore, the cooling device has an additional cooling channel for carrying a flow of additional coolant. This additional cooling channel is equipped with an opening section with a plurality of outlet openings. The additional coolant can exit in droplet form through these outlet openings of the outlet section.In this way, the drops of additional coolant can be brought onto an additional cooling section of the heat transfer channel in order to absorb heat from the heat transfer channel and thus from the hot heat transfer fluid by evaporating the additional coolant.

[0008] A cooling device according to the invention is therefore based on known solutions in which a cooling fluid can absorb and dissipate heat from the heat transfer fluid via a heat transfer coupling. The heat transfer fluid, like the cooling fluid, is preferably configured as a heat transfer fluid and a cooling fluid, respectively. Hot heat transfer fluid, which dissipates heat, for example in the form of engine oil from an internal combustion engine, is brought into heat-transferring contact with the cooling fluid. In the simplest way, the cooling section is formed by corresponding wall sections of the cooling channel and the heat transfer channel. When parts of the wall sections of the cooling channel and the heat transfer channel come into contact, heat conduction occurs, which is then made available for heat transfer between the heat transfer fluid and the cooling fluid.However, indirect couplings are also conceivable, which can be provided, for example, via thermal bridges or thermally conductive materials. In the simplest way, the heat transfer channel and the cooling channel in the cooling section are equipped with a common wall to minimize the thermal resistance between the heat transfer fluid and the cooling fluid.

[0009] In a cooling device according to the invention, an additional cooling channel is provided in addition to the regular cooling, which preferably performs the standard cooling functions. This additional cooling channel is separate from the heat transfer channel and also separate from the normal cooling channel and serves to guide a flow of additional cooling fluid. The additional cooling fluid is, in particular, exclusively conveyed in its liquid phase. The additional cooling fluid can exit through an opening section with a plurality of outlet openings and is thereby transformed into a droplet form. This can be ensured by appropriately designing the individual outlet openings, for example, in the nozzle or pore form described later. In droplet form, the surface area of ​​the additional cooling fluid increases shortly before or when the individual droplets impact an additional cooling section of the heat transfer channel.In principle, it is even conceivable to spray the additional coolant in droplet form onto this additional cooling section.

[0010] An additional cooling section can also be provided in the wall of the heat transfer channel. This additional cooling section is preferably designed separately from, and even somewhat spaced apart from, the cooling section. It can be a pipe wall or a planar configuration of the heat transfer channel. The additional cooling section is therefore, in particular, a hot wall section of the heat transfer channel, which is heated by the flow of hot heat transfer fluid within the channel. As soon as the additional cooling fluid, in liquid droplet form, impacts the additional cooling section when an additional cooling function is activated, this liquid additional cooling fluid evaporates into a vapor phase. In this process, heat is absorbed for heating to the boiling point and, furthermore, the enthalpy of vaporization for the transition to the gas phase.This dual heat absorption allows a large amount of heat to be absorbed from the auxiliary cooling section even with relatively small amounts of auxiliary coolant and dissipated in gaseous phase through the evaporated auxiliary coolant.

[0011] As can be seen from the preceding basic technical explanation, a cooling device according to the invention is equipped with two separate cooling functions. These are, firstly, the normal cooling function using the normal cooling channel and, secondly, the auxiliary cooling function using the auxiliary cooling channel. This allows for two separate switching modes, one for normal cooling and one for auxiliary cooling. This, in turn, makes it possible to design the cooling channel, and thus the maximum available cooling capacity, in a compact and cost-effective manner. However, if a significantly larger amount of heat is introduced into the heat transfer fluids in hot operating conditions or during hot operation of an internal combustion engine, this smaller cooling functionality will no longer be sufficient.In such a case, however, an additional cooling function can be activated, as provided by the additional coolant in the auxiliary cooling channel. In total, each of these two cooling functions can now be operated significantly more efficiently, since it is limited to the specific application. The respective efficiency point can be defined, so that the overall cooling system can be designed to be lighter, more cost-effective, and even more compact in its construction by enabling the switching of two cooling functionalities.

[0012] It can be advantageous if, in a cooling device according to the invention, a vapor channel is arranged between the auxiliary cooling section of the heat transfer channel and the opening section of the auxiliary cooling channel for the intake and removal of evaporated auxiliary coolant. This allows the auxiliary coolant to absorb and remove heat in a directed and controlled manner after it has absorbed heat in its vaporous phase. This removal can be provided passively, for example by free convection of the vapor from the auxiliary coolant, or actively, for example by means of ventilation devices. The guidance and, in particular, the removal of the vapor result in the retention of the vaporous auxiliary coolant being reduced or even completely avoided.In particular, after switching off the additional cooling function, this prevents or reduces unwanted condensation of the additional cooling fluid in this section of the vapor channel.

[0013] It is also advantageous if, in a cooling device according to the invention, the auxiliary cooling channel has a reservoir and / or is fluidly connected to a reservoir, in which auxiliary cooling fluid is stored. Such a reservoir also stores the auxiliary cooling fluid in liquid form. The reservoir can be integrated into the auxiliary cooling channel, for example, by means of a sufficiently large internal volume of the auxiliary cooling channel itself. However, an embodiment with a separate reservoir is preferred, as this significantly increases the flexibility of use. It also allows for simple and cost-effective refilling of the reservoir with the appropriate auxiliary cooling fluid. In the simplest case, within the scope of the present invention, the auxiliary cooling fluid is a water-containing liquid, in particular pure water or with appropriate additives.Refilling can be done from outside the vehicle, but also by the vehicle itself, for example by adding condensate from other areas.

[0014] It is further advantageous if, in a cooling device according to the invention, the auxiliary cooling channel includes a pump device for increasing the pressure within the auxiliary channel. Such a pump device is particularly designed with a forced-flow function and allows the pressure within the auxiliary cooling channel to be increased. This is especially relevant for increasing the pressure at the outlet of the auxiliary cooling fluid in droplet form. Therefore, if activation of the auxiliary cooling function is desired, this can be achieved in such a configuration by switching the pump device on and off accordingly. For purely qualitative switching, simply switching the pump device on and off is sufficient.However, it is of course also possible to adjust the dispensing speed and quantity of the additional coolant via the quantitative control of the pumping device, so that the cooling activity or cooling performance can also be controlled quantitatively by the additional cooling function.

[0015] It is also advantageous if, in a cooling device according to the invention, the auxiliary cooling channel has a pressure accumulator with a pressure relief valve for storing overpressure and pressurizing the auxiliary cooling fluid with the stored overpressure by opening the pressure relief valve. The pressure relief valve can be located in the area of ​​the opening section to apply pressurized auxiliary cooling fluid in droplet form through the outlet openings onto the auxiliary cooling section. However, a separate pressure chamber can also be provided, which serves as this pressure accumulator and contains a gaseous pressure medium. A suitable pump device can be arranged in this pressure accumulator as the pressure source.However, separate pressure sources may also be provided in the vehicle, which fulfill a corresponding function in other areas and can refill or increase this pressure reservoir as part of their normal operation.

[0016] Further advantages can arise if, in a cooling device according to the invention, the opening section has at least partially directed outlet openings with an outlet direction towards an additional cooling section, particularly in the form of a nozzle-like design. These directed outlet openings allow for targeted cooling, i.e., a precise droplet-shaped application of the additional cooling fluid onto the additional cooling section. Furthermore, the increased application rate achieved through a nozzle-like design allows for enhanced responsiveness of this additional cooling function. Cooling losses are reduced, and the efficiency of the additional cooling function, and in particular its operating speed, is significantly increased.

[0017] It is also advantageous if, in a cooling device according to the invention, the opening section has at least partially outlet openings in the form of outlet pores. The use of outlet pores allows for a particularly simple design of the opening section, for example, a porous material with defined pore distributions and / or defined pore sizes. The combination of these pores with directional outlet openings as described in the preceding paragraph is also possible. For example, in addition to the pores, drilled nozzle-like outlet openings can also be provided in this pore section. However, the type and orientation of the outlet of the auxiliary cooling fluid is fundamentally irrelevant, as long as this discharge occurs in droplet form onto the auxiliary cooling section.

[0018] Furthermore, it is advantageous if, in a cooling device according to the invention, one or more heat transfer channels are arranged on both sides of the additional cooling channel, in particular around the additional cooling channel.

[0019] These are provided in a symmetrical or rotationally symmetrical configuration, allowing for enhanced cooling performance, increased additional cooling surface area, and thus improved cooling efficiency. A very compact design enables the provision of a large surface area and therefore a high additional cooling capacity. This allows for the use of a tube-within-a-tube-within-a-tube solution, where the standard cooling circuit is located within the outermost section of this triple, nested tube assembly. An internal central tube contains an additional cooling channel for the centralized provision of the supplementary cooling function.

[0020] Also part of the present invention is a method for the additional cooling of a heat transfer fluid with a cooling device according to the invention, comprising the following steps: - Detecting an additional cooling requirement for the heat transfer fluid, - Generating additional cooling for the outlet of additional coolant on the additional cooling section of the heat transfer channel.

[0021] By using a cooling device according to the invention, a method according to the invention offers the same advantages as have been explained in detail with reference to a cooling device according to the invention.

[0022] A method according to the invention can be further developed in such a way that the additional cooling requirement is recognized on the basis of at least one of the following requirement parameters: - Temperature of the heat transfer fluid - Temperature of the cooling fluid - Temperature difference between the temperature of the heat transfer fluid and the cooling fluid

[0023] The preceding list is not exhaustive. In particular, the corresponding temperatures are compared with the associated cooling capacity of the normal cooling circuit and the auxiliary cooling circuit. Combining this with other parameters is also conceivable within the scope of the present invention. This allows for a precise definition of which cooling function is required for which temperature situations. This enables the system to be designed for both maximized cooling and maximum efficiency of the respective cooling function.

[0024] Further advantages, features, and details of the invention will become apparent from the following description, in which exemplary embodiments of the invention are described in detail with reference to the drawings. The features mentioned in the claims and in the description can be essential to the invention individually or in any combination. The drawings schematically show: Fig. 1 an embodiment of a cooling device according to the invention in cross-section, Fig. 2 a further embodiment of a cooling device according to the invention in cross-section, Fig. 3 a further embodiment of a cooling device according to the invention in cross-section and Fig. 4 another embodiment of a cooling device according to the invention in cross-section.

[0025] Fig. Figure 1 schematically shows a cross-section through a cooling device 10 of the present invention. A so-called tube-in-tube-in-tube solution is depicted, with the following arrangement visible from the inside out. A secondary cooling channel 40 is arranged centrally, which is surrounded on both sides or completely by a circumferential tubular steam channel 50. Radially outward from this is a circumferential tubular configuration of the heat transfer fluid channel 20, which in turn is surrounded by an outer tubular cooling channel 30. In normal operation, the heat transfer fluid WF flows in the heat transfer fluid channel 20. A flow of cooling fluid KF is present in the cooling channel 30.In this normal operation, when a cooling function is necessary, heat can be transferred from the heat transfer fluid WF via the cooling section 22, which here is designed as a contact surface between the two channels 20 and 30, so that the cooling fluid KF heats up and the heat transferred can be dissipated.

[0026] In particularly hot operating conditions, especially when the cooling function of the normal coolant KF is insufficient, an auxiliary cooling function is activated. This can be achieved by dispensing auxiliary coolant ZF from the auxiliary cooling channel 40. Dispensing can be accomplished through a porous opening section 42, allowing droplet-shaped auxiliary coolant ZF to contact the inner wall of the heat transfer channel 20 and, in turn, the auxiliary cooling section 24. There, the auxiliary coolant ZF evaporates by absorbing heat from the hot auxiliary cooling section 24 and can be discharged in vapor form through the vapor channel 50. This can be done actively, for example, by a fan (not shown). The rotationally symmetrical arrangement of the components described above results in a particularly efficient and compact design for both the normal cooling function and the auxiliary cooling.

[0027] Fig. Figure 2 shows a particularly simple embodiment of a cooling device 10 according to the invention, in which the same functionality is achieved as in Figure 2. Fig. 1 described. However, this is not a symmetrical design, but a one-sided design between the cooling function and the auxiliary cooling function. This means that on the upper side of the heat transfer channel 20, the corresponding heat transfer coupling is provided via the cooling section 22 with the cooling channel 30. Below this, a vapor channel 50 is provided, below which, in turn, the auxiliary cooling channel 40 is provided with an opening section 42 designed here as normal outlet openings 44. A vapor channel 50 is also provided for the same function as in Fig. 1 described available.

[0028] The embodiment of the Fig. 2 can be determined according to the Fig. 3. The system is further developed by providing a storage container 60. This container is equipped with a pump device 46 to ensure a corresponding pressure increase within the additional cooling channel 40. In this configuration, at least some of the outlet openings 44 are provided with defined outlet directions AR for the additional coolant ZF, so that the efficiency and reaction speed when the pump device 46 is switched on can be increased by increasing the velocity and defining the direction of the flow.

[0029] The Fig. Figure 4 shows an alternative or combination of embodiments of the Fig.3. Here too, an increase in the pressure of the auxiliary coolant ZF is desired. This can be achieved, for example, by means of a suitable pressure accumulator 48, which, as shown schematically here, can be pressurized by a piston. As soon as an auxiliary cooling function is required, this can be switched and released via the pressure relief valve 49, thus pressurizing the auxiliary coolant ZF.

[0030] The preceding explanation of the embodiments describes the present invention solely by way of examples. Naturally, individual features of the embodiments can be freely combined with one another, provided this is technically feasible, without departing from the scope of the present invention.

Claims

[1] Cooling device (10) for cooling a hot heat transfer fluid (WF) in a vehicle, comprising a heat transfer channel (20) for guiding a flow of the hot heat transfer fluid (WF) and a cooling channel (30) for guiding a flow of a cooling fluid (KF), wherein the heat transfer channel (20) and the cooling channel (30) are coupled to each other via a cooling section (22) for heat transfer, further comprising an additional cooling channel (40) for guiding a flow of additional coolant (ZF) with an opening section (42) having a plurality of outlet openings (44) for the outlet of the additional coolant (ZF) in droplet form onto an additional cooling section (24) of the heat transfer channel (20) for absorbing heat by evaporation of the additional coolant (ZF). [2] Cooling device (10) according to claim 1, characterized by, that between the additional cooling section (24) of the heat transfer channel (20) and the opening section (42) of the additional cooling channel (40) a vapor channel (50) is arranged for the intake and removal of evaporated additional coolant (ZF). [3] Cooling device (10) according to any of the preceding claims, characterized by , that the additional cooling channel (40) has a reservoir (60) and / or is fluidly connected to a reservoir (60), wherein additional cooling fluid (ZF) is stored in the reservoir (60). [4] Cooling device (10) according to any of the preceding claims, characterized by , that the additional cooling channel (40) has a pump device (46) for increasing the pressure in the additional cooling channel (40). [5] Cooling device (10) according to any of the preceding claims, characterized by, that the additional cooling channel (40) has a pressure accumulator (48) with a pressure relief valve (49) for storing overpressure and applying the stored overpressure to the additional cooling fluid (ZF) by opening the pressure relief valve (49). [6] Cooling device (10) according to any of the preceding claims, characterized by , that the opening section (42) has the outlet openings (44) as directed outlet openings (44) with an outlet direction (AR) in the direction of the additional cooling section (24), in the form of a nozzle-like design. [7] Cooling device (10) according to any of the preceding claims, characterized by , that the opening section (42) has at least some of the plurality of outlet openings (44) in the form of outlet pores. [8] Cooling device (10) according to any of the preceding claims, characterized by, that on both sides of the additional cooling channel (40) one or more heat transfer channels (20) are arranged around the additional cooling channel (40). [9] Method for the additional cooling of a heat transfer fluid (WF) with a cooling device (10) having the features of any one of claims 1 to 8, comprising the following steps: - Detecting an additional cooling requirement for the heat transfer fluid (HF), - Generating additional cooling by the outlet of additional coolant (ZF) onto the additional cooling section (24) of the heat transfer channel (20). [10] Method according to claim 9, characterized by , that the additional cooling requirement is recognized based on at least one of the following requirement parameters: - Temperature of the heat transfer fluid (HF) - Cooling fluid temperature (KF) - Temperature difference between the temperature of the heat transfer fluid (HF) and the cooling fluid (CF).

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