Expansion tank for the cooling circuit of a motor vehicle engine

Abstract

Expansion tank for a cooling circuit of a motor vehicle engine, comprising a tank upper part (1) to which an inlet line (7) for a coolant is arranged, and a tank lower part (2) to which an outlet line (9) for the coolant is arranged, wherein the inlet line (7) for the coolant is designed as a separate assembly from the tank upper part (1) with an outlet opening (14) arranged in a region of the tank lower part (2), characterized in that the inlet line (7) for the coolant is formed at least in a longitudinal region by a hose (10, 16) which is supported at least over a longitudinal region by a holder (11) which is also designed separately from the tank upper part (1), wherein the holder (11) is adapted to the course of the inside of the expansion tank and is provided with corresponding recesses (13).

Description

[0001] The invention relates to an expansion tank for a cooling circuit of an engine of a motor vehicle according to the preamble of patent claim 1. Furthermore, the invention relates to a cooling circuit with such an expansion tank and a motor vehicle with such an expansion tank.

[0002] Generally, such expansion tanks are used in cooling circuits for two purposes: firstly, to compensate for heat- or temperature-induced expansion of the volume of the coolant circulating within the cooling circuit, and secondly, to promote the degassing of gases absorbed within the coolant, particularly air, which can arise, for example, due to different flow rates at the inlet and outlet of the expansion tank. In particular, it is important to prevent air from the expansion tank from entering the cooling circuit of the respective engine.

[0003] This problem is particularly common in electric vehicles and their electric motors, as negative pressure in the expansion tank can arise, for example, due to different flow rates between the inlet and outlet lines. Relatively low temperatures in the cooling circuit play a significant role in this. To prevent such air pockets in the cooling circuits of electric motors, vent valves are commonly used today. However, these are very expensive and require additional electrical components to control the valves.

[0004] From FR 3 055 926 A1, an expansion tank for a cooling circuit of an engine of a motor vehicle is already known, which is formed by an upper tank part, on which an inlet line for a coolant is arranged, and a lower tank part, on which an outlet line for the coolant is arranged.

[0005] Furthermore, such an expansion tank is known from DE 10 2017 009 431 A1, which comprises an upper tank section with an inlet line and a lower tank section with an outlet line. In order to make the inlet line variable for different applications and coolants, inserts are provided, by means of which, for example, the coolant can be redirected. This inlet line is arranged essentially outside the expansion tank or the upper tank section.

[0006] Furthermore, DE 40 25 067 C1 discloses a vent line in the cooling circuit of an internal combustion engine, which connects the vent line of a radiator to an expansion tank located higher than its ceiling at an upper section of the expansion tank. An angled pipe element of the vent line extends into the expansion tank at an upper section, and the angled pipe element has an opening near the tank bottom. A vent valve is mounted at the highest point of the pipe section of the vent line located in the expansion tank.

[0007] Furthermore, JP 2008-75598 A discloses a reserve tank device equipped with a tank body and a flexible pipe. The tank body has an interior space for storing cooling water; a bottom wall defining the underside of the interior space; and an opening provided in the upper part of the interior space. The flexible pipe passes through the opening and connects the interior space of the tank body to a cooling water channel. The flexible pipe has a first end connected to the cooling water channel and a second end located on the opposite side to the first end and facing the bottom wall with a gap therebetween. The second end has a plurality of end surfaces arranged obliquely relative to the bottom wall. The end surfaces face the bottom wall at different angles.

[0008] Other containers for cooling circuits or similar applications are described in DE 10 2009 042 275 A1, DE 10 2017 119 704 A1 and FR 2 890 109 A1.

[0009] Finally, CN 1 04 747 268 A also discloses an expansion tank which comprises an externally mounted, multi-part inlet line and an outlet line.

[0010] The object of the present invention is to provide an expansion tank of the type mentioned at the outset, in which the introduction of gas, in particular air, into the cooling circuit or the associated coolant can be particularly favorably avoided.

[0011] This object is achieved according to the invention by an outlet line having the features of claim 1, by a cooling circuit having the features of claim 6, and by a motor vehicle having the features of claim 7. Advantageous further developments are the subject of the dependent claims.

[0012] The expansion tank according to the invention comprises an upper tank part, on which an inlet line for a coolant is arranged, and a lower tank part, on which an outlet line for the coolant is arranged, wherein the inlet line for the coolant is designed as a separate structural unit from the upper tank part and has an outlet opening arranged in the region of the lower tank part. Due to the separate or distinct design of the inlet line from the upper tank part, it is therefore possible to very easily regulate the flow rate of coolant in the region of the inlet line and, through suitable dimensioning, to adapt it, in particular, to the feedthrough of coolant in the region of the outlet line, such that the flow rates are preferably optimally adapted to one another.Thus, by separately designing and adapting the inlet line, it is possible to optimally prevent gas, particularly air, from entering the cooling circuit of the respective engine from the expansion tank. The outlet opening of the inlet line for the coolant is located in the area of ​​the lower part of the tank, so that it is preferably and in particular always located below a minimum coolant level within the expansion tank, thereby preventing additional gas, particularly air, from entering the coolant.

[0013] Especially in the case of cooling circuits of electric motors used to drive the respective motor vehicle, complex ventilation valves and their control systems can be dispensed with.

[0014] In particular, the expansion tank according to the invention makes it possible to adapt it to cooling circuits of different engines or of different sizes and different cooling requirements, without the upper part of the tank having to be adapted to the flow rates. Rather, with the expansion tank according to the invention, a uniform upper part of the tank that spans many design variants is sufficient, to which a corresponding, separate and design-specific inlet line can be attached, depending on the design of the expansion tank or its dimensions. This makes it easy to create a corresponding modular system, with a cross-design upper part of the tank and a design-specific unit that forms the inlet line for the coolant and is attached to the upper part of the tank.

[0015] To prevent the risk of gas, particularly air, from the expansion tank entering the cooling circuit of the respective engine, according to the invention, the inlet line for the coolant is formed, at least over a length section, by a hose, which is supported by a holder over at least a length section. In this context, the holder is designed separately from the tank's upper part, wherein the holder is adapted to the contour of the inside of the expansion tank and provided with corresponding recesses.

[0016] According to the invention, the inlet line is therefore formed by the hose, which is, for example, elastically flexible and whose cross-section and length can be easily adjusted to the coolant flow rate. This hose is preferably supported by a holder to ensure optimal positioning within the expansion tank, with the outlet opening of the hose always being arranged in the region of the lower part of the tank or below a minimum coolant level in order to prevent unwanted ingress of gas, in particular air. The separate design of the holder advantageously enables a corresponding modular system for adapting the expansion tank to different concepts, whereas the one-piece design of the holder, not claimed here, enables a particularly simple design.

[0017] In this context, it has proven further advantageous if the coolant inlet line is mounted inside the upper part of the tank. This allows the upper part of the tank or the inlet line to be adapted to the specific requirements of the respective cooling circuit in a particularly advantageous manner.

[0018] A further advantageous embodiment of the invention provides that the hose is adapted in length to the coolant flow rate. Thus, simply by cutting the hose to the appropriate length, the flow rate or other parameters of the coolant or cooling circuit can be adjusted accordingly. The specific design for a specific model can be achieved only by cutting the hose to the appropriate length.

[0019] The hose is preferably made of an elastically flexible material, which is supported by the corresponding holder. This ensures an optimal route of the hose along the expansion tank. Alternatively, however, another line could also be used instead of a hose.

[0020] The length of the holder according to the invention is preferably designed to be independent of the coolant flow rate and to have a uniform design. Accordingly, the holder, as well as the upper part of the tank, is preferably designed to be universal for at least some expansion tank variants. This allows, in particular, manufacturing and production costs to be reduced.

[0021] The invention also includes a cooling circuit for an engine of a motor vehicle with such an expansion tank and a motor vehicle with such an expansion tank according to claims 6 and 7, the advantages of which arise from what has already been described.

[0022] The invention also encompasses combinations of the features of the described embodiments. The invention therefore also encompasses implementations that each comprise a combination of the features of several of the described embodiments, unless the embodiments are described as mutually exclusive.

[0023] Exemplary embodiments of the invention are described below. Shown are: Fig. 1 a perspective view of an expansion tank for a cooling circuit of an electric motor of a motor vehicle with a tank upper part and a tank lower part, Fig. 2a, b, c show a perspective sectional view of the expansion tank according to a first embodiment with an inlet line for the coolant arranged therein, a perspective view of the separately formed inlet line and a perspective exploded view of the components of the inlet line, Fig. 3a, b, c show a perspective sectional view, a perspective and sectional exploded view and an enlarged, sectional perspective view of a compensation tank according to an alternative embodiment.

[0024] In Fig. Figure 1 shows a perspective view of an expansion tank for a cooling circuit of an engine, in this case an electric motor, of a drive in a motor vehicle, for example, a car. The expansion tank comprises an upper tank part 1 and a lower tank part 2, which are detachably connected to one another in the area of ​​a circumferential and sealed flange connection 3. A filler neck 4 for filling with coolant, in particular water containing antifreeze, is provided on the top side of the upper housing part 1. This filler neck 4 is closed with a cover 5.

[0025] It is also evident in Fig. 1 shows a connection piece 6 of an inlet line 7, explained in more detail below, for the coolant stored in the expansion tank and entering the expansion tank from the cooling circuit tank. A cooling circuit line can be attached to this connection piece 6 in a conventional manner, for example, by means of a pipe clamp or in another way.

[0026] On the underside of the lower part of the tank 2 there is a connecting piece 8 of an outlet line 9, via which the coolant held in the expansion tank can flow out of the tank into the cooling circuit of the drive motor.

[0027] In this case, the expansion tank serves two purposes in particular: firstly, to compensate for temperature-induced thermal expansion or volume changes in the coolant, and secondly, to degas air trapped in the coolant. To prevent air from the expansion tank from entering the cooling circuit of the electric vehicle or its drive motor, it is crucial that no negative pressure can develop within the expansion tank. This is a significant problem, especially at low temperatures in the cooling circuit.

[0028] For this reason, as will be explained below in conjunction with the Fig. 2a, Fig. 2b and Fig. 2c can be seen, in the interior or inside of the one inlet line 7 formed separately from the container upper part 1. Fig. 2a shows in a partial and cut perspective view the part 1 arranged inside the expansion tank attached inlet line 7, wherein the inlet line 7 in Fig. 2b is shown again separately without expansion tank at 2c in a perspective exploded view.

[0029] In particular from Fig. 2c shows that the inlet line in the present case is formed by a hose 10, which is, for example, elastically flexible and made of a suitable plastic material. This hose 10 is accommodated at least over a length region in a tubular or snorkel-shaped holder 11, which in turn is also formed separately from the expansion tank, in particular from the upper tank part 1, and is attached to the latter via an O-ring 12. The hose 10 is connected to the connection piece 6, or in a liquid-tight manner, so that coolant introduced into the expansion tank from the cooling circuit via the connection piece 6 reaches the interior of the expansion tank via the hose 10. The holder 11 is adapted to the shape of the inside of the expansion tank and provided with corresponding recesses 13.

[0030] As is particularly evident from Fig. As can be seen in Figure 2a, the hose 10 and the holder 11 are connected to the upper tank part 1, for example via suitable sliding connections, plug-in connections, or other types of connection, for example also with the aid of mechanical connecting means such as locking elements, screws, or the like. With an outlet opening 14 located in the region of the lower tank part 2, the hose 10 ends near a bottom of the expansion tank and near a baffle 15, which prevents a direct transfer of the coolant 9.

[0031] A special feature of the present expansion tank is that the inlet line 7, in particular its hose 10, as well as the holder 11, are designed as a separate structural unit from the upper tank section 1 and can therefore be individually adapted to the respective conditions of the cooling circuit for the drive motor. For example, and in particular, the length of the hose 10 can be varied in order to control the flow rate of coolant or to adapt it to the flow rate that flows into the cooling circuit via the outlet line 9. By appropriately designing the hose 10 in particular, a negative pressure in the expansion tank can be prevented, and thus air from the expansion tank can be prevented from entering the cooling circuit.This has the particular advantage that the tank top 1 can be used across multiple design variants of cooling circuits or drive motors, with only the respective inlet line 7, in this case in particular the hose 10, having to be adapted to the specific conditions of the cooling circuit and the coolant. Consequently, a respective hose 10 or a respective inlet line 7 can be easily arranged on the tank top, which is suitable for all design variants, in a design-specific manner.

[0032] In the present case, it is particularly intended that the holder 11 remains identical across at least some of the design variants and, in particular, has an identical length. Accordingly, preferably only the easily deflected hose 10 should be adapted to the respective cooling circuit.

[0033] Another design of the expansion tank is shown in the Fig. 3a and Fig. 3b in a respective sectional perspective view and perspective exploded view, whereby only the differences between the two embodiments will be discussed below and otherwise the components are at least substantially identical. The embodiment according to the Fig. 3a and Fig. 3b differs in particular by the alternative design of the hose 16, which in this case forms the inlet line 7. In the present case, the holder 17 is designed as a substantially channel-shaped or tubular element, which is formed in one piece with the upper part 1 of the expansion tank, whereby the one-piece embodiment is not part of the claimed invention. In contrast to the embodiment according to the Fig. 2a to 2c, therefore, no separate holder 11 is provided, but rather a holder 17 formed in one piece with the container upper part 1, which extends almost into the area of ​​the container lower part.

[0034] As from Fig. 3b, the hose 16 is inserted into the holder 17, which extends through a container wall of the container upper part 1 to the outside and forms the nozzle 6 for the cooling circuit in this area or is connected to the connection nozzle 6 in a suitable manner. Furthermore, from the Fig. 3a and Fig. 3b that the hose 16 extends close to the baffle 15 in the area of ​​the container bottom part 2, just as in the embodiment according to the Fig. 2a to 2c - up to near the lower end of the tank bottom part 2 or the expansion tank.

[0035] Fig.Figure 3c shows, in a partial and sectional perspective view, the hose 16 again in the area of ​​the connecting piece 6, at which the expansion tank is connected to the cooling circuit or a line of this cooling circuit. In this case, the hose 16 is also made of an elastically flexible plastic material. The upper tank part 1 and the lower tank part 2 are also predominantly made of corresponding plastic materials, as are the holders 11 and 17. Thus, in this case, the hose 16 is also formed as a separate structural unit from the upper tank part 1 and is held internally thereto. List of reference symbols 1 container top 2 Container bottom part 6 connection pieces for input line 7 Input line 8 connection pieces for output line 9 Output line 10 hoses (variant 1) 11 Holder, separate from the container top 12 O-ring 13 recesses 14 Exit opening 15 Baffle 16 hose (variant 2) 17 Holder, one-piece with the container top 2

Claims

[1] Expansion tank for a cooling circuit of an engine of a motor vehicle, comprising a tank upper part (1), on which an inlet line (7) for a coolant is arranged, and a tank lower part (2), on which an outlet line (9) for the coolant is arranged, wherein the inlet line (7) for the coolant is designed as a separate structural unit from the tank upper part (1) with an outlet opening (14) arranged in a region of the tank lower part (2), characterized by that the inlet line (7) for the coolant is formed at least in one length region by a hose (10, 16), which is supported at least over one length region by a holder (11), which is also formed separately from the tank upper part (1), wherein the holder (11) is adapted to the course of the inside of the expansion tank and is provided with corresponding recesses (13). [2] Expansion tank according to claim 1, characterized bythat the inlet line (7) for the coolant is attached inside the upper part of the tank (1). [3] Expansion tank according to one of the preceding claims, characterized by that the length of the hose (10, 16) is adapted to a flow rate of coolant. [4] Expansion tank according to one of the preceding claims, characterized by that the hose (10, 16) is made of an elastically flexible material. [5] Expansion tank according to one of the preceding claims, characterized by that the length of the holder (11) is independent of the flow rate of coolant. [6] Cooling circuit for an engine of a motor vehicle with an expansion tank according to one of claims 1 to 5. [7] Motor vehicle with an expansion tank for a cooling circuit of an engine of the motor vehicle according to one of claims 1 to 5.

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