EP1923549B1 - Cooling system for a motor vehicle - Google Patents

Description

The invention relates to a cooling system for a motor vehicle according to the preamble of claim 1 and to a method for cooling a component of a motor vehicle according to the preamble of claim 21.

DE 103 19 762 A1 describes a cooling circuit of an internal combustion engine of a motor vehicle, wherein a part of the cooling circuit is branched off for cooling charge air of the internal combustion engine. The branched-off part of the cooling circuit is circulated by a coolant-flow-driven turbine pump, wherein in an embodiment according to FIG Fig. 6 is possible to bridge the turbine pump via an adjustable multi-way valve.

The US 3,134,371 discloses a cooling system for an internal combustion engine in which a radiator, intercooler and an oil cooler in the circuit of the internal combustion engine are connected.

It is the object of the invention to provide a cooling system for a motor vehicle that, on the one hand, provides the cooling of a vehicle engine and, on the other hand, provides low-temperature cooling of a further heat exchanger with simple means.

This object is achieved for an aforementioned device with the characterizing features of claim 1. The arrangement of the pump unit in the main branch a simple construction is possible, which is particularly feasible in vehicle engines with respect to space or connections difficult to access inner coolant circuit.

In addition, a branch line is advantageously provided, wherein the branch line leads from the main branch to the low-temperature cooler. Such a branch line allows in a simple manner that the low-temperature radiator is charged in a certain mode with only circulated by the main pump coolant. Such an operating mode is particularly useful in a warm-up phase of the vehicle engine, in which there is no circulation of the coolant in the main branch. In a preferred embodiment, the branch line branches in the flow direction towards the vehicle engine and before the main pump. As a result, the flow resistance of the main pump is avoided for the branched coolant flow, the branch after the vehicle engine structurally simple manner and in particular in existing systems can be integrated.

Generally advantageously, the pump unit comprises a coolant-driven turbine and a pump driven therefrom, wherein in particular turbine and pump are arranged on a common shaft. Such a pump unit is convenient and inexpensive. Due to the arrangement on the common shaft construction costs and components are saved, in particular with an optional connection of the coolant circuits through the coolant radiator and the low-temperature radiator no costly sealing measures between the turbine and pump part of the pump unit are required. The pump unit may preferably be formed of plastic and generally features according to the cited document DE 103 19 762 A1 exhibit.

In a preferred embodiment, the inner coolant circuit comprises a throttle member, wherein a coolant flow of the branch line is adjustable via the throttle member. About the throttle member is controlled in a simple manner, the pressure drop across the branch line and thus the coolant flow of the branch line. In particular, in a warm-up phase of the engine, in which the branch line is flowed through, is a throttling of the coolant flow in the interior Cooling circuit of the vehicle engine harmless in a wide context and possibly leads advantageously to a faster heating of the vehicle engine during cold start.

In an advantageous embodiment, the throttle member is arranged as a particular thermo-mechanical throttle valve in the inner coolant circuit. For the purposes of the invention, a thermomechanical valve is to be understood as meaning any component which has an immediate conversion of heat into a mechanical force, such as expansion elements, bimetallic elements and the like. Under this term, such components are to be detected in which the control characteristic of the thermo-mechanical element z. B. additional electrical heating elements can be influenced; Such components are known in practice in the form of thermostats under the term "map thermostats". To save costs and space, it is preferably provided that the throttle member is designed as a structural unit with a branch of the branch line.

In this case, in the coolant flow of the heat exchanger, the throttle valve for adjustable limitation of the current through the heat exchanger is arranged. In this way, an immediate limit of the amount of coolant flowing through the heat exchanger can be set, which z. B. may be advantageous if the heat exchanger in certain operating conditions should have a reduced cooling capacity or when an increased coolant flow is requested by the vehicle engine during the warm-up phase. In this context, the regulation of the throttle valve may depend, in particular, on parameters of the element to be cooled by the heat exchanger or generally on a control electronics of the vehicle.

Generally, it is provided that, at least for a complete opening of the thermostat, the coolant flow through the vehicle engine and the coolant flow through the heat exchanger are substantially separated. As a result, sufficient cooling of the coolant flow flowing through the heat exchanger can be achieved even when the vehicle engine is warm. In warm-running vehicle engines, the coolant flow on the outlet side of the engine typically has temperatures of up to 120 ° C, so that the flow through the low-temperature radiator with such a hot coolant would not lead to sufficient cooling for the feed of the heat exchanger. In this mode of operation, the coolant flow separated from the engine cooling circuit is then circulated through the low temperature cooler and heat exchanger by means of the pump unit, the drive energy for the pump part of the pump unit being taken from the flow of vehicle engine coolant in the main branch.

In a further advantageous embodiment, a check valve is arranged in the coolant flow of the heat exchanger. In this way it can be ensured even in case of malfunction and unfavorable pressure conditions that the coolant in the branch of the heat exchanger can flow only in a defined direction, whereby in particular a shortage of the vehicle engine is excluded with coolant.

In the first operating mode, in particular in the course of warming up of the vehicle engine, the coolant circuit can be operated directly via the main pump through the heat exchanger (return via the first branch) and, when the engine is warm, by means of the return via the second branch via the pump unit.

In an advantageous, because space-saving and cost-effective design of the coolant radiator and the low-temperature radiator are designed as a structural unit. The cooler can z. B. in the field of a vehicle front in the structural unit next to each other. Particularly preferably, the coolers are arranged one behind the other, wherein the low-temperature cooler is arranged with respect to the cooling air flow in front of the coolant radiator. In an advantageous embodiment, the structural unit additionally comprises the pump unit, whereby the costs are also optimized and space is saved. In addition, there are fewer potential weak points due to connections of hoses and the like. In this sense, a branch line between the main branch and a coolant flow of the low-temperature radiator is likewise preferably integrated in the structural unit and, expediently, also a valve member for setting a coolant flow through the low-temperature radiator. It is particularly optimal in the course of structural integration of the addressed components, that ultimately a cooler component with branch line, valve means for controlling the flow through the branch line and pump unit is provided, wherein the structural unit only one inlet and one outlet for the low-temperature cooler and the Has coolant radiator. Such a unit is particularly easy to integrate into existing vehicle construction spaces and in particular modularly replaced by existing components such as conventional main radiator.

By means of a suitable arrangement of branch lines, it can advantageously be achieved that in the first operating mode the cooling medium flow of the heat exchanger previously passes through both the coolant cooler and the low-temperature cooler. In this way, a particularly large cooling capacity is provided in this mode or in the warm-up phase of the vehicle engine, so that it is achieved in particular that the entering into the heat exchanger temperature of the coolant despite the previous passage of the vehicle engine has an approximately or the same low temperature as in normal operation with circuits separated by the pump unit,

In an expedient embodiment, the pump unit is arranged downstream of the coolant cooler, so that this unit does not constitute a resistance to be flowed through in the first operating mode, in particular when the coolant flow branches off through the heat exchanger between coolant radiator and pump unit.

In an advantageous embodiment, the heat exchanger is a charge air cooler for the vehicle engine. It may be the only or an additional intercooler. Alternatively or additionally, the heat exchanger may also be an exhaust gas cooler, in particular for an exhaust gas recirculation system of the vehicle engine. Likewise alternatively or additionally, the heat exchanger can dissipate heat from an electrical energy source to the coolant, wherein the vehicle has in particular a hybrid drive with an electric motor supplied by the energy source. In principle, it is possible that in the low-temperature Kühlkrels a plurality of heat exchangers are arranged with different cooling functions, wherein the arrangement can be serial and / or parallel.

The object of the invention is achieved by a method according to the preamble of claim 21 by the characterizing features of claim 21. The fact that the selection of the circulation of the coolant takes place via a thermostat, manufacturing costs and complexity and susceptibility of the system can be reduced. The thermostat is expedient at the same time the main thermostat of the cooling circuit of the vehicle engine. The inventive method is carried out with a cooling system according to one of claims 1 to 20.

Further advantages and features of the invention will become apparent from the embodiments described below and from the dependent claims.

Fig. 1

zeigt eine schematische Ansicht einer ersten Ausführungsform eines erfindungsgemäßen Kühlsystems.

Fig. 2

zeigt das Kühlsystem aus Fig. 1 in einer Warmlaufphase des Fahrzeugmotors.

Fig. 3

zeigt das Kühlsystem aus Fig. 1 in einem Betriebszustand mit betriebswarmem Fahrzeugmotor.

Fig. 4

zeigt eine zweite Ausführungsform eines erfindungsgemäßen Kühlsystems.

Fig. 5

zeigt das Kühlsystem aus Fig. 4 in einer Warmlaufphase des Fahrzeugmotors.

Fig. 6

zeigt das Kühlsystem aus Fig. 4 in einem normalen Betriebszustand mit betriebswarmem Fahrzeugmotor.

Fig. 7

zeigt eine dritte Ausführungsform eines erfindungsgemäßen Kühlsystems.

Fig. 8

zeigt eine vierte Ausführungsform eines erfindungsgemäßen Kühlsystems.

Fig. 9

zeigt das Kühlsystem aus Fig. 8 in einer Warmlaufphase des Fahrzeugmotors.

Fig. 10

zeigt das Kühlsystem aus Fig. 8 in einem normalen Betriebszustand bei betriebswarmen Fahrzeugmotor.

Hereinafter, several preferred embodiments of a cooling system according to the invention will be described and explained in more detail with reference to the accompanying drawings.

Fig. 1

shows a schematic view of a first embodiment of a cooling system according to the invention.

Fig. 2

shows the cooling system Fig. 1 in a warm-up phase of the vehicle engine.

Fig. 3

shows the cooling system Fig. 1 in an operating condition with warm engine vehicle engine.

Fig. 4

shows a second embodiment of a cooling system according to the invention.

Fig. 5

shows the cooling system Fig. 4 in a warm-up phase of the vehicle engine.

Fig. 6

shows the cooling system Fig. 4 in a normal operating condition with warm engine vehicle engine.

Fig. 7

shows a third embodiment of a cooling system according to the invention.

Fig. 8

shows a fourth embodiment of a cooling system according to the invention.

Fig. 9

shows the cooling system Fig. 8 in a warm-up phase of the vehicle engine.

Fig. 10

shows the cooling system Fig. 8 in a normal operating condition with warm vehicle engine.

The cooling system according to Fig. 1 includes an internal cooling circuit with a main pump 1, a main pump subsequent vehicle engine 2, z. B. a gasoline or diesel engine of a passenger car, a vehicle engine 2 downstream thermostat 3 and a thermostat 3 downstream and the main pump 1 in the inner circuit upstream throttle valve. 4

Between thermostat 3 and throttle valve 4, a branch 5 a branch line 6 is provided, which opens on the input side of a low-temperature cooler 7 in a low-temperature cooling circuit, which includes the low-temperature cooler 7 and this below a heat exchanger 16. About the heat exchanger 16 is present charge air of a compressor 9, z. B. an exhaust gas turbocharger of the engine, cooled before it is supplied to the vehicle engine 2 as combustion air.

From the thermostat 3, a main branch of the coolant flow of the vehicle engine 2 passes through a coolant radiator 8 with fan 8 a arranged thereon, which assumes the main cooling function for the engine 2 when the engine 2 is warm and the main thermostat 3 is open. Downstream of the thermostat 3 and in front of the coolant cooler 8, a pump unit 10 is arranged in the main branch, wherein the coolant flow of the main branch, ie the flow through the coolant cooler 8, drives a drive turbine 10 a of the pump unit 10. The mechanical drive energy of the pump unit 10 thus comes ultimately from the main pump 1, which may be integrated in a generally known construction, in particular in the vehicle engine 2 and z. B. may be driven by a timing belt or accessory drive belt of the engine.

A pump side 10 b of the pump unit 10 is arranged in front of the low-temperature cooler 7, so that the coolant by means of the pump unit 10th can be promoted by low-temperature cooler 7 and subsequent heat exchanger 16.

The heat exchanger 16 is followed by a throttle valve 11, via which the size of the coolant flow through the heat exchanger 16 is adjustable.

After the throttle valve 11, the cooling circuit to a branch 12, the first branch 12a on the output side of the coolant radiator 8 and before the main pump 1 opens into the main branch. In the branch 12 a, a check valve 13 is arranged, via which it is ensured that the exit-side coolant of the coolant cooler 8 can not enter the branch 12 a, but is reliably returned to the vehicle engine 2.

A second branch 12b of the branch 12 leads to the suction side of the pump 10b of the pump unit 10.

The invention now works as follows:

In a warm-up phase of the internal combustion engine 2, the in Fig. 2 is shown, the thermostat 3 is closed, so that the main pump 1 circulates only the inner cooling circuit of the vehicle engine 2 in a known per se. However, after the main thermostat 3 or structurally integrated with the main thermostat 3 a branch 5 in a branch line 6, which is adjustable in its share via the branch 5 subsequent throttle valve 4. This branched-off part of the coolant flow conveyed by the main pump 1 enters the low-temperature cooler 7 and subsequently into the heat exchanger 16, wherein the coolant cooled by the low-temperature cooler 7 has considerably lower temperatures than the coolant leaving the engine 2. The warm-up phase of internal combustion engines is typically up to internal circulation temperatures around 85 ° C (start of thermostat opening). It has been found that, at these temperature ranges, cooling by the low-temperature cooler 7 is regularly sufficient to allow indirect charge air cooling or also exhaust gas cooling.

The coolant lines shown in dotted lines in the respective operating state (In Fig. 2 : Warm-up phase of the engine) does not flow through. In the warm-up phase, in particular the pump unit 10 is not flowed through, so that the entire flowing through the heat exchanger 16 Kühlmitteistrom is funded by the main pump 1.

The operating state after opening of the thermostat 3 with operating warm combustion engine 2 is in Fig. 3 shown. In this case, the branch line 6 is no longer flowed through by coolant, since the inner coolant circuit is shut off by the position of the thermostat 3. Accordingly, there is no longer any connection between the coolant circuit of the vehicle engine 2 and the coolant circuit of the heat exchanger 16 with low-temperature cooler 7. Rather, in this state, two separate circuits exist, one of which is an engine coolant circuit with main pump, vehicle engine, thermostat, turbine side 10 a of the pump unit 10 and main cooler 8. The second Kühlmittelkrels is a low-temperature coolant circuit with low-temperature cooler 7, heat exchanger 16, throttle valve 11 and pump part 10b of the pump unit 10. This separation allows a sufficiently low coolant temperature at the heat exchanger 16 even when the engine is warm.

Another embodiment of the invention is in Fig. 4 shown. With regard to the conception of the engine cooling circuit, the difference with the first exemplary embodiment results here that the thermostat 3 is arranged on the output side of the coolant cooler 8 and in front of the main pump 1, which is also referred to as "entry control" with respect to the vehicle engine 2. The branch 5 of the branch line 6 takes place in the inner circuit in front of the thermostat 3. Since thus when the engine is warm (see illustration to Fig. 6 ) would always exist a certain pressure drop across the branch line 6, the branch line 6 is designed shut off via a suitable means. In the present case, this barrier is designed as an acting on branch line 6 and cooling line of the inner circle throttle member 14, wherein the throttle member 14 may cause a complete shut-off of the line 6. Depending on the flow resistance of the main thermostat 3, it may be that the pressure drop across the branch line 6 in the warm-up phase (see Fig. 5 ) is not sufficiently large, so that the throttle member 14 can cause throttling of the inner circle to increase the pressure drop across the branch line 6. Instead of this dual function of selectively shutting off the branch line 6 in normal operating condition (see Fig. 6 ) and a throttling of the line of the inner circle with open branch line (see Fig. 5 ), the throttle member 14 may also be integrated as a simple serial throttle valve in the branch line 6. This is a possible solution in particular if a sufficient pressure drop for the branch line 6 is available via the flow resistance of the main thermostat 3.

The throttle member 14 is formed in a preferred embodiment as a thermomechanical valve. This eliminates costly and trouble-prone control means, as would be required for electromechanical control valves. Preferably, the thermo-mechanical throttle member 14 is analogous to a map thermostat is formed, for example by combining a thermomechanical component such as a Dehnstoffelement with a controllable electrical heating element for influencing the control characteristics of the thermo-mechanical element.

In the third embodiment according to Fig. 7 it is a modification of the embodiment according to Fig. 4 to Fig. 6 , The branch 5 the branch line 6 is arranged in this case after a motor outlet-side branch 15 of the inner circle and immediately in front of the drive side 10a of the pump unit 10. The throttle member 14 is serially integrated as an adjustable cross-sectional narrowing throttle valve in the branch line. An embodiment according to Fig. 7 Depending on the given space is particularly simple and can be integrated with only a few changes in a motor vehicle.

In particular, it is in an embodiment according to Fig. 7 possible, all of the components marked with A (see dashed enclosure A in Fig. 7 ) as a structural unit. These are the coolant cooler 8, the low-temperature cooler 7, the pump unit 10 and the throttle member 14 and the branch line 6. This integrated structural unit is ideally a cooler module with only two input-side connection lines and two output-side connection lines.

Such an integration of the pump 10 and the throttle member 14 can be done for example in a water tank of the coolant radiator or the low-temperature radiator. The water box could form part of the pump housing. It may be the water tank of a multi-circuit cooler, ie a combination of main cooler and low-temperature cooler. This may be either a single-row system, in which the low-temperature cooler 7 is arranged in the same cooler block next to the coolant cooler 8, wherein in particular the pump unit 10 may be integrated in the partition wall area. However, it can also be a double-row system, in which low-temperature coolers 7 and coolant coolers 8 are formed one behind the other, but as an integrated component with a common, internally divided water box, wherein preferably the pump unit 10 is integrated in the common water box.

In a fourth embodiment according to Fig. 8 In contrast to the aforementioned embodiments, the pump unit 10 is arranged downstream of the coolant cooler 8. The branch line 6 branches off via its branch 5 on the outlet side of the coolant cooler 8, but even before the pump unit 10. In the branch line 6 is a throttle member 14 for shutting off the branch line 6 in normal operation of the cooling system (see Fig. 10 ) arranged.

In the cooling system according to Fig. 8 there is the advantage that in the warm-up phase of the engine (see Fig. 9 ) the branched and the heat exchanger 16 flowing through the coolant flows through the coolant cooler 8 and subsequently through the low-temperature cooler 7. This has the favorable consequence that in the case of the warm-up phase, is entered in the heat energy of the vehicle engine 2 in the later the heat exchanger 16 by flowing coolant, a particularly large cooling capacity by combining the two coolers 7, 8 is provided.

Analogous to the structural integration A in the third embodiment, the components according to the label B (see Fig. 8 ) in the fourth embodiment structurally integrated before, namely coolant radiator 8, low-temperature cooler 7, branch line 6, throttle member 14 and pump unit 10th

Claims (21)

1. A cooling system for a motor vehicle comprising a vehicle engine, a main pump (1) for circulating a coolant of a vehicle engine (2) at least in one internal coolant circuit,
   a thermostat (3) for the temperature-dependent conveyance of the coolant through a main branch, wherein a coolant radiator (8) is disposed in the main branch, a pump unit (10) that is drivable by the flowing coolant, a low-temperature radiator (7) through which the coolant can flow, and a heat exchanger (16) disposed downstream of the low-temperature radiator (7), wherein the coolant flow of the heat exchanger (16), at least in a first operating mode, is connected to the coolant flow of the vehicle engine (2), wherein the pump unit (10) is disposed in the main branch,
   characterized in that, in the direction of flow, a throttle salve (11) is disposed downstream of the heat exchanger (16) and a branching (12) is disposed downstream of the throttle value (11), wherein a first branch (12a) of the branching is designed as a return line to a coolant circuit of the vehicle engine (2), and wherein a second branch (12b) is designed as a return line to a pump (10b) of the pump unit (10), which is disposed downstream of which the low-temperature radiator (7).
2. The cooling system according to claim 1, characterized in that a branch line (6) is provided, wherein the branch line (6) leads from the main branch to the low-temperature radiator (7).
3. The cooling system according to claim 2, characterized in that, in the direction of flow, the branch line (6) branches off downstream of the vehicle engine (2) and upstream of the main pump (1).
4. The cooling system according to one of the preceding claims, characterized in that the pump unit (10) comprises a coolant-operated turbine (10a) and a pump (10b) driven whereby, wherein the turbine (10a) and the pump (10b), in particular, are disposed on a common shaft.
5. The cooling system according to one of the claims 2 to 4, characterized in that the internal coolant circuit comprises a throttle element (4, 14), wherein a coolant flow of the branch line (6) can be adjusted by way of the throttle element (4, 14).
6. The cooling system according to claim 5, characterized in that the throttle element (4, 14), as a thermomechanical throttle element in particular, is disposed in the internal coolant circuit.
7. The cooling system according to one of the claims 5 or 6, characterized in that the throttle element (14) is designed as a structural unit with one branching (5) of the branch line (6).
8. The cooling system according to one of the preceding claims, characterized in that the throttle element (11) for adjustable limiting the coolant flow through the heat exchanger (16) is disposed in the coolant flow of the heat exchanger (16).
9. The cooling system according to one of the preceding claims, characterized in that, at least when the thermostat (3) is fully open, the coolant flow through the vehicle engine (2) and the coolant flow through the heat exchanger (16) are substantially separated.
10. The cooling system according to one of the preceding claims, characterized in that, at least in an open position of the thermostat, the coolant flow through the heat exchanger (16) is circulated at least partially by way of the pump unit (10).
11. The cooling system according to one of the preceding claims, characterized in that a non-return value (13) is disposed in the coolant circuit of the heat exchanger (16).
12. The cooling system according to one of the preceding claims, characterized in that the coolant radiator (8) and the low-temperature radiator (7) are in the form of a structural unit.
13. The cooling system according to claim 12, characterized in that the structural unit also comprises the pump unit (10).
14. The cooling system according to claim 12 or 13, characterized in that the structural unit comprises a branch line (6) between the main branch and a coolant flow of the low-temperature radiator (7).
15. The cooling system according to one of the claim 12 to 14, characterized in that the structural unit comprises a valve element (14) for adjusting a coolant flow through the low-temperature radiator (7).
16. The cooling system according two one of the preceding claims, characterized in that, in the first operating mode, the coolant flow of the heat exchanger (16) first passes through the coolant radiator (8) and the low-temperature radiator (7).
17. The cooling system according la to claim 16, characterized in that the pump unit (10) is disposed downstream of the coolant radiator (8).
18. The cooling system according to one of the preceding claims, characterized in that the heat exchanger (16) is a charge air cooler for the vehicle engine.
19. The cooling system according to one of the preceding claims, characterized in that the heat exchanger is an exhaust-gas cooler, more particularly for an exhaust-gas recirculation system of the vehicle engine.
20. The cooling system according to one of the claims 1 to 17, characterized in that the heat exchanger transfers heat from an electrical energy source to the coolant, wherein, more particularly, the vehicle comprises a hybrid derive halving an electric motor that is supplied by the energy source.
21. A method for cooling charge air or exhaust gas of a motor vehicle, comprising the steps:

    a. circulate a coolant of a vehicle engine (2) using a main pump (1),

    b. circulate at least a portion of the coolant through a low-temperature radiator (7) and a heat exchanger (16) using a pump unit (10), wherein a pump (10b) of the pump unit (10) is driven a coolant-operated turbine (10a) that is driven by the coolant flow that is circulated by the main pump (1), and

    c. depending on an operating state, circulate at least a portion of the coolant through the low-temperature radiator (7) and the heat exchanger (16) using the main pump (1),

    characterized in that
    a selection of the circulation of the coolant according two step b. or step c. takes place by way of a thermostat (3),
    wherein the method is carried out using a device according to one of the claims 1 to 20.

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