EP2427639B1 - Fail-safe rotary actuator for a coolant circuit - Google Patents

Description

Fail-safe turntable for a coolant circuit to avoid damage to an internal combustion engine due to insufficient cooling capacity in case of failure of the turntable.

Such fail-safe turntables are preferably used to provide an emergency operation of the Kühlmiftelkreislaufs an internal combustion engine when the controlled by the turntable coolant is no longer sufficient for proper cooling of the engine due to a malfunction of the turntable.

The DE 102 43 778 A1 shows an actuating device with an electromotive rotary drive through which an adjusting element, in particular a rotary valve of a rotary valve, about a rotational axis between a first end position and a second end position is rotatably driven and acted upon by a spring from the first end position out. The electromotive rotary drive is designed as a reversing drive and the Federbeauschlagung of the actuating element is effective only between the first end position and an intermediate position, wherein the intermediate position between the first end position and the second end position. If the control element embodied as a rotary slide valve is a control valve in a coolant circuit of an internal combustion engine, cooling of the internal combustion engine in emergency operation is maintained by the rotation of the actuating element resulting from the spring action of the control element in the event of failure of the electromotive rotary drive.

A disadvantage of the adjusting device shown, however, is that the emergency operation is initiated immediately after failure of the rotary drive due to the constant presence of spring action of the actuating element. As a result, the cooling medium, depending on the ambient temperature, engine load and driving speed, no longer heat up to the operating temperature, resulting in a loss of efficiency of the internal combustion engine during emergency operation results.

The object of the present invention is therefore to provide a fail-safe turntable for a coolant circuit, which can initiate an emergency operation for the coolant circuit as required.

This object is solved by the features of patent claim 1.

A fail-safe turntable for a coolant circuit, in particular for a multiple partial circuits having coolant circuit of an internal combustion engine, a coolant pump for circulation of the coolant within the coolant circuit, and a plurality of housing Durchströmöffnungen exhibiting rotary valve housing in which at least one rotary valve with at least one rotary valve flow-through rotatably mounted is, wherein the housing flow openings are fluidly connected to at least one partial circuit and can be brought by a rotational movement of the rotary valve in at least partially overlap with the rotary valve flow and wherein a thermostatic valve when exceeding a temperature limit of the coolant parallel to the rotary valve guided flow path of a the partial circuits to the coolant supply pump opens.

By a temperature-dependent switchable thermostatic valve is arranged parallel to the rotary valve, in a failure of the rotary valve control an emergency operation can be ensured by the fact that the thermostatic valve for the coolant an alternative flow path to the coolant pump opens. Due to the temperature-dependent circuit of the thermostatic valve, this flow path is switched only when the temperature of the coolant has reached a critical for the operation of the internal combustion engine limit temperature. As a result, the engine is not prevented from reaching the operating temperature despite a malfunction of the turntable, which contributes to a reduction in fuel consumption and emissions. In addition, the turntable is very robust, since no components required for emergency operation attack directly on the rotary valve, which allows easy movement of the rotary valve and low component wear. Also, the thermostatic valve has a very low wear, since it has to be operated very rarely.

In a preferred embodiment, a radiator feed directs coolant from the engine to a heat exchanger and a radiator return directs the coolant exiting the heat exchanger to the rotary valve. The heated by the internal combustion engine coolant is passed through the radiator flow to the heat exchanger, in which it can cool. The exiting from the heat exchanger, cooled coolant is passed through the radiator return to the corresponding housing flow opening of the rotary valve. From the radiator flow can also branch off a bypass and direct heated coolant to another housing flow-through. By a rotation of the rotary valve whose rotary valve flow-through can be brought into at least partially overlap with the corresponding housing flow openings. Thus, it is possible to regulate the proportion of the inflowing into the rotary valve coolant from the bypass and the radiator return exactly.

In a preferred embodiment, the temperature of the coolant in the radiator feed is compared with the limit temperature of the coolant for switching the thermostatic valve. By using the temperature of the heated coolant in the radiator feed for comparison with the specific limit temperature can be responded to a critical increase in the coolant temperature of the internal coolant in the engine faster. Furthermore, the temperature measurement is independent of the currently achieved cooling rate of the downstream heat exchanger, which can vary considerably during operation.

In a preferred embodiment, the thermostatic valve to a check valve which is mounted in a valve seat and is pressed by a spring sealingly against this, and arranged on the shut-off valve push rod which is actuated by an expansion element, which deals with the coolant of the radiator expands in conjunction with the expansion element when the coolant reaches its limit temperature and lifts the shut-off valve out of the valve seat against the pressure of the spring via the push rod. By the thermostatic valve has an expansion element, preferably in the form of a wax capsule, which is in contact with the coolant from the radiator feed, compliance with the limit temperature can be monitored without additional electronics. Rather, the limit temperature is determined by the material properties of the wax used, which expands upon reaching the limit temperature and thus exerts a force on the push rod arranged thereon. The shut-off valve mounted at the other end of the push rod, which is preferably designed as a poppet valve, is pressed by a spring sealingly against a complementary valve seat. When the expansion element now exerts a force on the push rod, the shut-off valve can lift off the valve seat, which opens a guided parallel to the rotary valve flow path.

In a preferred embodiment, the thermostatic valve on both sides of the shut-off valve arranged and acted upon with coolant chambers, wherein a first chamber with coolant from the radiator return can be acted upon and a second chamber has a fluidic connection to the suction port of the coolant pump. The chambers are preferably designed as cages, so that the coolant as easily as possible can flow in and out. The first chamber is always filled with coolant from the radiator return, while the second chamber usually contains coolant from the rotary valve.

In a preferred embodiment, a gap is formed between the rotary valve and the rotary valve housing, through which the coolant from the second chamber of the thermostatic valve can flow to the suction port of the coolant pump. The coolant can reach regardless of the current position of the rotary valve through the annular gap formed to the suction port of the coolant pump. Additional radial passage openings in the rotary valve can facilitate the passage of the coolant from the second chamber of the thermostatic valve in the rotary valve.

In a preferred embodiment, the coolant delivery pump conveys the coolant sucked from the rotary valve into a heating circuit and / or an internal combustion engine intake.

In a preferred embodiment, a heating heat exchanger and / or a heating feed pump and / or a Heizungsabsperrventil are arranged in the heating circuit. By the coolant also flows through the heat exchanger in addition to the heat exchanger, the available cooling surface increases. The heating conveyor pump is preferably operated electrically and can thus promote the coolant through the cooling circuit in addition to the coolant supply pump if necessary. The Heizungsabsperrventil can be closed when not required heating power, which causes a faster heating of the refrigerant in the other sub-circuits in normal operation.

In a preferred embodiment, a further shut-off valve, in particular a further rotary valve, is arranged in the internal combustion engine intake. By the arrangement of a further shut-off valve in the engine inlet If necessary, the coolant flow to the internal combustion engine can be interrupted and redirected in a targeted manner into the heating circuit. By the further shut-off valve is designed as a rotary valve, a rotational movement in dependence on each other can be carried out by a direct or indirect connection with the other rotary valve.

In a preferred embodiment, when the limit temperature of the coolant is exceeded, the Heizungsabsperrventil is opened, so that the coolant from the coolant supply pump can be promoted via the heater core in the engine. This is particularly necessary if the designed as a rotary valve further shut-off valve in the engine inlet due to a malfunction can no longer pass coolant. In this case, it is necessary to direct a coolant flow from the rotary actuator via the heating circuit back into the internal combustion engine.

Further details, features and advantages of the invention will become apparent from the following description of a preferred embodiment with reference to the drawings.

• Fig. 1 eine schematische Darstellung der Anordnung eines ausfallsicheren Drehstellers in dem Kühlmittelkreislauf;
• Fig. 2 eine Schnittansicht eines ausfallsicheren Drehstellers;
• Fig. 3 eine Schnittansicht eines ausfallsicheren Drehstellers mit geschlossenem (Fig. 3a) und geöffnetem (Fig. 3b) Thermostatventil;

Show:

• Fig. 1 a schematic representation of the arrangement of a fail-safe turntable in the coolant circuit;
• Fig. 2 a sectional view of a fail-safe turntable;
• Fig. 3 a sectional view of a fail-safe turntable with closed ( Fig. 3a ) and opened ( Fig. 3b ) Thermostatic valve;

According to Fig. 1 is an internal combustion engine 2 with coolant from several sub-circuits, in particular a main cooling circuit 3 and a heating circuit 4, applied. The internal combustion engine 2 consists essentially of a cylinder head and a cylinder crankcase, which are flushed by a located in a water jacket coolant, wherein the resulting heat of combustion of the fuel at least partially passes to the coolant. In the cooling circuit, a fail-safe turntable 1 is arranged, through which the coolant flows of the respective subcircuits 3 and 4 can be controlled as needed. The turntable 1 consists of at least one rotary valve 9 which are rotatably mounted in a rotary valve housing 8. The rotary valve housing has a plurality of housing flow-through openings, which can be brought into at least partial overlap with the corresponding rotary valve flow-through openings 11 of the rotary valve 9 by a rotational movement. In the turntable 1, a coolant supply pump 5 is arranged, the suction mouth can be acted upon with coolant from the rotary valve 9 and this feeds into the heating circuit 4, and engine inlet 25. The delivery rate of the coolant delivery pump 5 and the distribution of the coolant volume flows in the individual sub-circuits 3 and 4 can be regulated by a rotation of the rotary valve 9 in conjunction with an actuation of the shut-off valve 10 arranged in the engine inlet 25. The shut-off valve 10 can also be designed as a further rotary valve and coupled to the movement of the rotary valve 9. The main cooling circuit 3 passes coolant from the internal combustion engine 2 via the radiator feed 16 to a heat exchanger 14 and a housing throughflow opening of the bypass 30. The coolant exiting from the heat exchanger 14 passes via the radiator return 15 to the housing throughflow opening of the radiator return line 15 Position of the first rotary valve 9 with respect to the rotary valve housing 8, the incoming coolant from the bypass 30 and the radiator return 15 with variable flow rate can flow into the rotary valve 9 or is prevented from flowing. This may be the case, for example, in the event of a failure of the rotary valve drive and would lead to inadequate cooling of the connected internal combustion engine 2 to lead. Therefore, the rotary valve 9 is associated with a thermostatic valve 13, which opens a parallel flow path, bypassing the rotary valve 9, if necessary, especially when exceeding the limit temperature of the coolant in the radiator feed 16. With an open thermostatic valve 13, the coolant from the radiator return 15, bypassing the rotary valve 9, can reach the suction mouth 24 of the coolant delivery pump 5. The coolant delivery pump 5 conveys the coolant into the engine inlet 25 and the heating circuit 4, wherein the heating circuit 4 consists of a Heizungsabsperrventil 27, a Heizungsförderpumpe 29 and a heater core 26. The Heizungsabsperrventil 27 is preferably open in emergency mode and the electrically driven heating conveyor pump 29 may provide additional capacity at 5 too low flow rate of the coolant supply pump. Thus, regardless of the current position of the rotary valve 9 and the check valve 10, a coolant flow through the heat exchanger 14 and / or the heater core 26 can be maintained.

According to Fig. 2 includes a fail-safe turntable 1 for a coolant circuit a rotary valve housing 8, in which a rotary valve 9 is rotatably mounted. The rotary valve housing 8 has a plurality of housing through-flow openings 6 and 7, in particular a housing throughflow opening 6, which can be acted upon by coolant from the radiator return 15, and a housing throughflow opening 7, which can be acted upon with coolant from the bypass 30, wherein the bypass 30th branches off from the radiator feed 16. The rotary valve 9 has a plurality of rotary valve flow-through openings 11 and 12, in particular a rotary valve flow passage 11, which is associated with the housing flow passage of the radiator return 15, and a rotary valve flow passage 12 which is associated with the housing flow-through opening of the bypass 30, wherein a rotary movement of the rotary valve 9, the rotary valve flow openings 11 and / or 12 are brought into at least partially overlap with the housing flow openings 6 and / or 7 can. On the rotary valve 9, a thermostatic valve 13 is arranged, which is designed as a wax capsule expansion element 21 is disposed in the radiator feed 16 and expands when a specific limit temperature of the coolant is exceeded. To the expansion element 21, a push rod 20 is arranged, which carries a terminal shut-off valve 17 which is pressed by a spring 19 sealingly against a valve seat 18. On both sides of the check valve 17 chambers 22 and 23 are formed, wherein a first chamber 22 below the check valve 17 fluidly communicates with the radiator return 15 and a second chamber 23 above the check valve 17, regardless of the current position of the rotary valve 9, with the suction mouth 24 a coolant supply pump 5 is fluidically connected.

According to Fig. 3 has a fail-safe turntable for a coolant circuit a rotary valve housing 8, in which a rotary valve 9 is rotatably mounted. The rotary valve housing 8 has a plurality of housing through-flow openings 6 and 7, in particular a housing flow-through opening 6, which can be acted upon by coolant from the radiator return 15, and a housing flow-through opening 7, which can be acted upon by coolant from the bypass 30. The rotary valve 9 has a plurality of rotary valve flow-through openings 11 and 12, in particular a rotary valve flow-through opening 11 for the radiator return 15 and a rotary valve flow passage 12 for the bypass 30, wherein by a rotation of the rotary valve 9, the rotary valve flow openings 11 and / or 12 in at least partially overlap with the housing flow openings 6 and / or 7 can be brought. Overlaps as in Fig. 3a illustrated at least one rotary valve flow-through opening 11 or 12 with at least one housing flow-through opening 6 or 7, so coolant can penetrate into the rotary valve 9 and sucked from the suction port 24 of the coolant supply pump 5. Overlaps as in Fig. 3b none of the rotary valve through-flow openings 11 or 12 with a housing throughflow. 6 or 7, so no coolant can get into the rotary valve 9 and thus not to the suction port 24 of the coolant supply pump 5. This can for example be the case in case of failure of the rotary valve drive and would lead to insufficient cooling of the connected internal combustion engine. Therefore, a thermostatic valve 13 is arranged on the rotary valve 9, which opens or closes depending on the temperature of the coolant present in a radiator inlet, in particular closes at a temperature below a limit temperature ( Fig. 3a ) and at a temperature above a limit temperature opens ( Fig. 3b ). For this purpose, a shut-off valve 17 is pressed by a spring 19 sealingly against the valve seat 18. When the limit temperature is exceeded, an expansion element presses the shut-off valve 17 out of the valve seat 18 via a push rod 20, resulting in an alternative flow path for the coolant. In this case, the coolant from the radiator return 15 from the first chamber 22 into the second chamber 23 of the thermostatic valve 13 and pass from there through the gap between the rotary valve 9 and rotary valve housing 8 to the suction port 24 of the coolant supply pump 5. Alternatively, it is possible to provide the rotary valve 9 in this area with further radially distributed flow openings, through which the coolant from the second chamber can more easily penetrate into the rotary valve 9, which allows a better flow rate of the coolant supply pump 5 in emergency operation.

List of reference numbers:

1

turntable

2

Internal combustion engine

3

Main cooling circuit

4

Heating circuit

5

Coolant pump

6

Housing flow-through radiator return

7

Housing throughflow bypass

8th

Rotary slide housing

9

rotary vane

10

Rotary valve in the engine intake

11

Rotary slide flow-through radiator return

12

Rotary vane bypass Bypass

13

thermostatic valve

14

heat exchangers

15

Cooler return

16

radiator feed

17

shut-off valve

18

valve seat

19

feather

20

pushrod

21

expansion element

22

first chamber

23

second chamber

24

saugmund

25

Engine inlet

26

Heater core

27

Heizungsabsperrventil

29

Heating pump

30

bypass

Claims (10)

1. Fail-safe rotary actuator (1) for a coolant circuit, in particular for a coolant circuit having a plurality of sub-circuits (3, 4) of an internal combustion engine (2), comprising a coolant delivery pump (5) for circulating the coolant within the coolant circuit, and a rotary-slide housing (8) having a plurality of housing pass-through openings (6, 7), in which housing at least one rotary slide (9) having at least one rotary-slide pass-through opening (11, 12) is rotatably mounted, the housing pass-through openings (6, 7) being in fluid communication with at least one sub-circuit (3, 4) and being able to be brought into overlap with the rotary-slide pass-through openings (11, 12), at least in part, by rotating the rotary slide (9), characterised in that a thermostat valve (13) opens a flow path guided parallel to the rotary slide (9) from one of the sub-circuits (3, 4) to the coolant delivery pump (5) when a temperature limit of the coolant is exceeded.
2. Fail-safe rotary actuator for a coolant circuit according to claim 1, characterised in that a radiator supply line (16) conveys coolant from the internal combustion engine (2) to a heat exchanger (14), and a radiator return line (15) conveys the coolant exiting the heat exchanger (14) to the rotary slide (9).
3. Fail-safe rotary actuator for a coolant circuit according to either claim 1 or claim 2, characterised in that the thermostat valve (13) is controlled in response to a comparison of the temperature of the coolant in the radiator supply line (16) with the temperature limit of the coolant.
4. Fail-safe rotary actuator for a coolant circuit according to any of claims 1 to 3, characterised in that the thermostat valve (13) comprises a shut-off valve (17) which is mounted in a valve seat (18) and is pressed in a sealing manner against the valve seat by a spring (19), and a push rod (20) which is arranged on the shut-off valve (17), and can be actuated by an expansion member (21),, said expansion member (21), which is in communication with the coolant of the radiator supply line (16), expanding when the temperature limit of the coolant is reached and lifting the shut-off valve (17) from the valve seat (18) via the push rod (20) in opposition to the pressure applied by the spring (19).
5. Fail-safe rotary actuator for a coolant circuit according to any of claims 1 to 4, characterised in that the thermostat valve (13) has chambers (22, 23) arranged on each side of the shut-off valve (17) which can receive by coolant, a first chamber (22) receiving coolant from the radiator return line (15), and a second chamber (23) being in fluid communication with the suction port (24) of the coolant delivery pump (5).
6. Fail-safe rotary actuator for a coolant circuit according to any of claims 1 to 5, characterised in that a gap is formed between the rotary slide (9) and the rotary-slide housing (8), through which gap the coolant can flow from the second chamber (23) of the thermostat valve (13) to the suction port (24) of the coolant delivery pump (5).
7. Fail-safe rotary actuator for a coolant circuit according to any of claims 1 to 6, characterised in that the coolant delivery pump (5) conveys coolant drawn in from the rotary slide (9) to a heating circuit (4) and/or a supply line (25) of the internal combustion engine.
8. Fail-safe rotary actuator for a coolant circuit according to claim 7, characterised in that a heating heat exchanger (26) and/or a heating delivery pump (29) and/or a heating shut-off valve (27) are arranged in the heating circuit (4).
9. Fail-safe rotary actuator for a coolant circuit according to claim 7, characterised in that a further shut-off valve (10), in particular a further rotary slide, is arranged in the supply line (25) of the internal combustion engine.
10. Fail-safe rotary actuator for a coolant circuit according to any of claims 1 to 9, characterised in that the heating shut-off valve (27) is opened when a temperature limit of the coolant is exceeded, such that the coolant can be conveyed from the coolant delivery pump (5) to the internal combustion engine (2) via the heating heat exchanger (26).

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