DE8702534U1 - Temperature control device for the coolant of internal combustion engines - Google Patents

Description

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ff · « * « < r Authorized representative at Patent Attorney ; MeH|eigfrs^.6 European Patent Office Dipl.-Ing. Volkhard Kratzsch ·· «D-TOM EsMingi European Patent Attorney Deutsche Bank Esslingen 210806 Post Office Check Office Stuttgart 10004-701 Telephone Stuttgart (0711) 317000 cable «krapatent» esslingenneckar

Gustav Wahler GmbH u. Co 7300 Esslingen

12 February 1987 Attorney File 4245

Temperature control device for the coolant of internal combustion engines

The invention relates to a temperature control device for the coolant of internal combustion engines of the type defined in the preamble of claim 1.

In known devices of this type (DE-OS 35 16 502) , the temperature of the coolant is measured by the sensor in the flow line or return line and sent to the control device for further action. If necessary, the control device activates the servomotor, which adjusts the control valve accordingly. As a rule, the temperature control device has fixed and reproducible operating points. However, there is an increasing effort to change the temperature control device depending on the different operating conditions of the internal combustion engine during operation in order to better and more precisely adapt the coolant temperature to the current operating state of the internal combustion engine, e.g. its speed and/or load. The temperature control device in known temperature control devices

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The effort required for this is extremely high. Above all, it has been shown that with these methods the control valve only works very slowly and returns to its original state very slowly.

The invention is based on the object of designing a temperature control device of the type mentioned in the preamble of claim 1 in such a way that a rapid change in the control behavior of the control valve and thus control of the coolant temperature is possible using simple means.

The object is achieved according to the invention in a temperature control device of the type mentioned in the preamble of claim 1 by the features in the characterizing part of claim 1.

External heating of the sensor, e.g. to a value that exceeds its response threshold, is easily possible using simple and inexpensive means. If the external heating is carried out electrically, for example, this can be implemented particularly easily in terms of control or regulation technology. External heating of the sensor to its response temperature can be carried out very quickly, which means that a change in the control characteristics of the control valve can be achieved very quickly. It is particularly advantageous that even after the external heating of the sensor is switched off, it is cooled back to its original state very quickly, which takes place using the coolant that is constantly applied to the sensor and has a significantly lower temperature in comparison. In a particularly simple way, the invention thus uses the coolant applied to the sensor as a cooling medium to cool the externally heated sensor. Special cooling devices for cooling the sensor as quickly as possible are therefore not necessarily required. The advantage is that this method allows extremely rapid cooling of the sensor when the external heating is switched off.

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This not only allows a very quick change in the control characteristics of the control valve, but also, conversely, the original state can be restored very quickly.

The temperature control device with

A sensor located in the coolant flow of the supply line or return line is particularly simple and cost-effective as well as space-saving. The arrangement of the sensor means that when the heating device is switched off, the sensor is very quickly cooled back to its original state by the coolant flowing in the line, which is constantly pressurizing it. This means that after the control characteristics of the temperature control device have been changed, the original state is very quickly restored by switching on the heating device.

Further advantageous embodiments of this temperature control device according to the invention are set out in claims 2 - 12. A design according to claim 13 is particularly advantageous, in which the sensor and actuator of the control valve are combined to form a single temperature-dependent operating actuating element. Further advantageous features are set out in claims 14 - 20. Such a temperature control device is compact, inexpensive and as

complete assembly unit available, so that it can easily be 30

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Further details and advantages are provided in the following description. 5

The full wording of the claims is not reproduced above solely to avoid unnecessary repetition, but instead reference is made to it only by mentioning the claim number, whereby, however, all of these claim features are to be regarded as expressly disclosed at this point and essential to the invention. »All of the features mentioned in the above

* ' and the following description mentioned characteristics as well as

the features that can only be determined from the drawing

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;' The invention is described below with reference to the drawings

: 20 examples shown in the diagrams are explained in more detail. They show:

Fig. 1 a schematic side view

of parts of an internal combustion engine

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Fig. 2 is a schematic side view 30 approximately corresponding to that in

Fig. 1 according to a second embodiment,

Fig. 3 a schematic section with

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'I Temperature control device according to

In a third example.

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Fig. 1 shows a schematic of an internal combustion engine 10 with a temperature control device 11, which has a cooler 12 with an inlet 13 and an outlet 14 for the coolant. The inlet 13 is connected to the internal combustion engine outlet 16 via a flow line 15 and the outlet 14 is connected to the internal combustion engine inlet 1B via a return line 17. A bypass line 19 connecting the two runs between the flow line 15 and the return line 17.

In this first embodiment, the temperature control device 11 has a control valve 20 in the feed line 15 and at the same time in the bypass line 19, which in this embodiment consists of a conventional valve, the valve closure member of which is designed to alternately control the feed line 15 and/or the bypass line 19. The control valve 20 is of a conventional type. It has, in the usual way, for example in a housing, two valve closure members arranged on the same axis, each of which controls an associated valve opening. For the sake of simplicity, a circuit diagram borrowed from pneumatics has been used in the drawing for the control valve 20. The control valve 20 has an inlet 21 and outlet 22, both of which are located in the feed line 15 and make it more or less permeable depending on the switching position. Furthermore, the control valve 20 has a bypass connection 23 with which it is connected to the bypass line 19.

When the internal combustion engine 10 is cold, the passage in the feed line 15 is blocked, as shown, and only the valve closure element of the control valve 20, which creates the short circuit, is open. The coolant coming from the internal combustion engine passes through the feed line 15 and is led by the control valve 20 via the inlet 21 and the bypass connection 23 to the bypass line 19 and from there back to the

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-&egr;&igr; internal combustion engine inlet 18.

In the case of a control valve 20 designed as a normal thermostatic valve, this is then switched from the B position shown to the other when the coolant in the flow line 15 has reached the opening temperature of this thermostatic valve. The short-circuit path via the bypass line 19 is then blocked and the passage in the flow line 15 to the cooler 12 is opened.

31 π Kl the coolant temperature falls below the response π temperature, the control valve 20 is returned to the position shown. Depending on the current coolant temperature in the flow line 15, mixed positions between the two positions explained can also arise. In this respect, a coolant circuit for internal combustion engines is known.

The special feature of the temperature control device 11 according to the first embodiment is that the control valve 20 is not a conventional thermostat valve, but instead a valve actuated from the outside via a servomotor 24. The servomotor 24 is only indicated schematically, as is its actuator 25 at the output of the servomotor, which is geared to the invisible valve closure member of the control valve 20. The servomotor 24 can, for example, consist of an electric actuator, e.g. an electric motor, in particular a direct current motor, which can be switched with regard to the direction of rotation and thus the valve actuation direction assigned to it. This can be a known direct current stepper motor or a direct current gear motor.

The servomotor 24 is assigned a control device 26 that controls it. Individual characteristic map variables, for example those detected by sensors of the internal combustion engine, are fed to the control device 26. These individual

Characteristic map variables are schematically marked with arrows and the reference symbols 1, 2 and 3 for them. Of these, characteristic map variable 3 consists of the coolant temperature recorded in the feed line 15. To record this, a sensor 27 is arranged in the feed line 15, which is connected to the control device 26 via a control line 28. The other characteristic map variables 1, 2 and other characteristic map variables not shown are, for example, the exhaust gas temperature and/or the speed and/or the torque of the engine 10.

and/or the negative pressure in the intake manifold and/or a pressure difference in a vacuum box and/or the oil temperature - door or similar other machine-side characteristic map variables .

15

If the characteristic map variable 3, i.e. the coolant temperature in the supply line 15, reaches a value that is above a predetermined value, the control device 26 is activated, which then controls the servomotor 24 to adjust the control valve 20 from the position shown to another, whereby the passage through the supply line 15 to the cooler 12 is released and the coolant passes through the cooler 12 and is cooled.

, 25 Another special feature of the temperature control device 11 is that the sensor 27 is provided with a schematically indicated heating device 29. This can be integrated into the interior of the sensor 27 or it is designed as an external heating device and placed on the outside of the sensor 27. The heating device 29 is connected to the control device 26 via a control line 30, via which the heating device 29 is switched on or off as required depending on machine-side or other characteristic field variables. In Fig. 1, a sensor 27' in the area of the return line 17 is also only schematically indicated in dashed lines.

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Such a sensor can be present in addition to the sensor 27 or instead of it. It is designed in the same way as the sensor 27 and is connected to the control device 26.
5

Using the temperature control device 11 according to Fig. 1, the temperature of the coolant can be controlled as follows. Depending on individual characteristics, namely those of the internal combustion engine 10 and/or other external parameters, the sensor 27, which is exposed to the coolant temperature in the feed line 15 and detects this temperature, can be subjected to external heating when the heating device 29 is switched on. The servomotor 24 is then actuated via the control device 26 and the control valve 20 is actuated via this in such a way that the coolant temperature in the feed line 15 is reduced. This is achieved by closing more strongly in the area of the bypass connection 23 and opening more strongly in the area of the inlet 21 and outlet 22 in such a way that more cooled coolant flows back into the internal combustion engine 10 via the return line 17. This state is maintained as long as the heating device is switched on. As soon as the control device 26 causes the heating device 29 to be switched off via the control line 30, the previously heated sensor 27 is cooled down again very quickly by the colder coolant flow in the supply line 15. The fact that coolant flows in the supply line 15 is used here to automatically cool the sensor 27, which usually has significantly lower temperatures than the response temperature that causes the heating device 29 to be switched on.

The heating device 29 arranged on the outside of the sensor 27 is located on a

located, temperature-sensitive area of the sensor 27. The heating device 29 has, for example, an electrical heating element not specifically shown, e.g. an electrical heating coil, which is placed on the outside of the housing of the sensor 27.

In the second embodiment shown in Fig. 2, reference numerals that are 100 times larger are used for the parts that correspond to the first embodiment, so that reference is made to the description of the first embodiment to avoid repetition.

Deviating from the first embodiment, in the second embodiment in Fig. 2 the control valve 120 is placed in the area of the return line 117 leading back from the cooler 112 with the branch of the bypass line 119. Furthermore, some details of the

140 has a coaxial valve rod 141 with two valve closure members 142, 143 thereon, which are arranged at an axial distance from one another and are each designed as a valve disk. The first valve closure member 142 controls an associated first valve seat 144.

The second valve closure member 143 controls an associated second valve seat 145. The valve rod 141 is seated in the usual manner in a holder 146 in which it is longitudinally displaceable, the holder 146 having wall openings in the area of the return line 117, so that when the valve seat 144 is released by the valve closure member 142, a flow passage is created in the area of the return line 117 through the control valve 120. A return spring 147 is only indicated schematically, which is supported and tensioned between the holder 146 and the valve closure member 142 and functions as a closing spring. The housing 140 connects the

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.5 coolant from the cooler 112 is passed through the return line 117 through the valve seat 144 and mixed in the housing 140 with a coolant flow that is also introduced into the housing 140 via the bypass line 119 and the valve seat 145. A suitably tempered mixed flow is created according to the temperatures of both coolant flows, which is passed back into the internal combustion engine 110.

In the second embodiment in Fig. 2, the sensor 127 is also part of the control valve 120 and is arranged in the wall of the latter, in the return area 117. The sensor 127 is connected via the control line 128 to the control device 126, which in turn can control a schematically indicated servomotor, which in turn can actuate the control valve 120. This is done here by the valve rod 141 being moved by the servomotor 124 in a translational manner in the axial direction of the valve rod 141 to one side or the other.

The sensor 127 is clearly positioned with a part of its temperature-sensitive area in the flow of the return line 117 and in such a way that it is continuously exposed to the returning coolant. The external heating device 129 is arranged on a likewise temperature-sensitive area of the sensor 127 located outside the return line 117 and the wall 146, for example in the form of an electrical heating element, which is wound onto the outside of the housing as a heating coil.

The heating device 129 is connected via the control line to the control device 126, via which

Line 130 is used to switch the

Heating device 129. The heating device 129 is thermally insulated from the wall 148. Suitable insulating elements 131 are used for this purpose.
5

If, for example, it is assumed that the coolant which is fed back to the internal combustion engine 110 in the return line 117 currently has a temperature of 90 ⁰ C, and for some reason this coolant temperature should be reduced, the heating device 129 is switched on via the control device 126 and the control line 130. The sensor 127 is heated to its operating temperature, whereby the sensor

127 reports a temperature to the control device via the control line 128, on the basis of which the control device 126 activates the servomotor 124, which then adjusts the control valve 120 in such a way that the second valve seat 1"5 is further closed by its valve closure member 143, while the other valve seat 144 is opened even further. As a result, less coolant with a higher temperature reaches the housing 140 via the bypass line 119, but instead more cooled coolant coming from the cooler 112, which reaches the housing 140 of the / \ 25 control valve 120 via the return line 117 and mixes there with the reduced proportion of bypass coolant. As long as the heating device 129 is switched on, this changed position of the control valve 120 is maintained via the servomotor 124.

30

As soon as the heating device 129 is switched off, the temperature control device 111 reacts with an extremely short time delay, because the sensor 127 is then cooled down very quickly by the coolant in the return line 117, which is at a lower temperature than the heating temperature. This rapid cooling

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The heating device 129, in particular the sensor 127, uses the cooler coolant flowing in the return line 117, so that special external cooling devices associated with the heating device 129 are not required. As a result, the sensor 127 provided with the heating device 129 can adapt to the respective temperature conditions in a very short time and thus quickly. On the one hand, the sensor 127 can be heated to the response temperature very quickly via the heating device 129. On the other hand, a ^very rapid recooling can be achieved in the manner described when the heating device 129 is switched off.

In an embodiment that differs from Fig. 2 and is not shown, the sensor 127 can work directly on the actuator 124 and actuate it. This is done, for example, via a control line or, depending on the design of the sensor 127 and/or the actuator 124, via a direct transmission element. The sensor 127 can thus be designed as a temperature-dependent actuating element. This contains, for example, an expansion material, e.g. wax, that expands when the temperature increases in the housing visible in Fig. 2 and partially protruding into the return line 117. This wax chamber can, for example,

can be closed off with a membrane. Then, for example, a pressure medium line or an actuating rod, a Bowden cable, a single mechanically connected pipe containing force-transmitting balls or the like leads from the sensor 127 to the actuator 124.

mechanical transmission element that is able, when the heating device 129 is switched on and the expansion material is heated above its response temperature, to transmit the accompanying expansion of the expansion material, which is represented as a bulge or displacement of the membrane, to the actuator 124. The transmission can also take place via a pressure medium line, e.g. hydraulic or pneumatic line.

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As soon as the sensor 127 develops a corresponding force due to the switched-on heating device 129, this is fed to the servomotor 124, where it either directly leads to the displacement of the valve stem

B 141 or is converted there into an actuating force developed by the actuator 124 itself.

The sensor 127 can also be designed as a known expansion element, from whose housing a piston is led out, which is pushed out of the housing until the heating device 129 is switched on and the response temperature of the sensor 127 is reached. The displacement movement can be transmitted directly to the control valve 120, in particular its valve rod 141, via a transmission rod, or it is initially guided to the servomotor 124 in this way.

The actuator 124 can be a mechanical or pressure medium-operated working cylinder. In another embodiment, the actuator 124 can also be designed as a temperature-dependent actuating element, e.g. a known expansion element, the moving part of which, e.g. a piston, is firmly connected to the valve rod 141 of the control valve 120 and moves it in a translational manner.

In the third embodiment shown in Fig. 3, for the reasons mentioned above, reference numerals that are 200 times larger are used for identical parts.

The special feature of the third embodiment is that the control valve 220 in the form shown represents a complete, ready-to-install unit which contains all components.

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The sensor and the actuator working on the valve rod 241 are combined here to form a single temperature-dependent actuating element 250, which is designed as a known expansion element. Within a housing 251 that is firmly sealed to the outside, an expansion material, e.g. wax, that expands when heated is contained. A piston 252 is immersed in this expansion material, which is forced into the housing 251 by a return spring in the actuating element 250 and/or the return spring 247. If the expansion material in the housing 251 expands when the temperature increases and the response temperature of the expansion material is reached, the piston 252 is pushed out of the housing 251 in the direction of the arrow 253 against the effect of the return spring. As a result, the valve rod 241, which is firmly connected to the piston 252 and coaxial with it, is displaced in the same direction. If the expansion material in the housing 251 cools down again, this results in a reduction in volume, so that the piston 252 is partially pushed back into the housing 251 by the return spring in the opposite direction to arrow 253, with the valve rod 241 also being displaced.

The described temperature-dependent actuating element 250 is arranged with a part of its housing 251 and the interior of this, which forms a sensing part, within the return line 217. The remaining part of this sensing part is arranged outside this line. It extends outwards over the wall 248. On this part 254 of the housing 251, an external heating device 229 is arranged on the outside, which is switched on via the control line 230 and is fed when designed as an electrical heating device.

The actuating element 250 is arranged coaxially to the two valve seats 244 and 245 in the housing 240, whereby it passes transversely and completely through the return line 217.

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The part of the return line 217 coming from the cooler (not shown) runs approximately parallel to the other part and opens into the housing 240 on the side of the first valve seat 244 pointing downwards in Fig. 3. 5

The bypass line 219, on the other hand, runs transversely to these parts of the lines 217 and opens into the housing 240 approximately coaxially with the actuating element 250, forming with it the second valve seat 245. The part of the return line 217 containing the actuating element 250 is guided in an approximately U-shape around the housing 240 with the valve rod 241 and the two valve closure members 242, 243. \ ) It opens with its opening 232 at one point into the

Housing 240 which is located between the first valve seat 244 and the second valve seat 245.

The first valve closure member 245 consists of a plate which is slidably mounted on the valve rod 241 and is pressed against the valve seat by the return spring 247. The return spring 247 is supported with the end at the top in Fig. 3 on arms 234 which are firmly connected to the housing 240. If the valve rod 241 is moved in the direction of arrow 253, i.e. towards the top in Fig. 3, it takes the first valve closure member 242 with it via a radially projecting annular shoulder 233, whereby the return spring 247 is compressed more strongly.

The second valve closure member 243 also consists of a valve plate, which is also held so that it can move on the valve rod 241. A locking ring 235 fixed to the valve rod 241 at the end prevents the valve closure member 243 from coming off. This is pressed against the locking ring 235 by means of an overstroke spring 236. The overstroke spring 236 is axially supported on an annular shoulder 237 of the valve rod 241.

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When the valve rod 241 is moved in the direction of the valve seat 245, the valve closure member 243 rests on the valve seat 245 and if the valve rod 241 is moved even further in this closing direction, the overstroke is absorbed by the overstroke spring 236 which compresses more strongly.

If the heating device 229 is switched on via the control line 230, the expansion material of the actuating element 250, e.g. wax, is heated above its reaction temperature, e.g. 120 ⁰ C, so that the expansion material expands while the piston 252 is displaced in the direction of the arrow 253. This results in a displacement of the valve rod 241 in the same direction, whereby the first valve closure member 242 is lifted off the valve seat 244 and a passage is created there, while the other valve closure member 243 is at least brought closer to the valve seat 245, if not completely blocking it, so that correspondingly less or no coolant is introduced into the housing 240 via the bypass line 219. Instead, colder coolant now enters the housing 240 via the line 217 coming from the cooler, which is guided in a U-shape through the open valve seat 244 and through the opening 232, flows around the actuating element 250 located transversely in the line 217 and is guided in the direction of the internal combustion engine. As long as the heating device 229 is switched on, with the resulting adjustment of the control valve 220, the temperature of the coolant being returned to the internal combustion engine drops.

If the heating device 229 is switched off, the previously heated actuating element 250 is very quickly heated by the coolant flowing around it in the line 217 and leading to the internal combustion engine, which, in contrast,

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has a significantly lower temperature, so that a very rapid reset of the actuating element 250 and thus of the control valve 220 occurs.

In all, the temperature control device 211 is simple, lightweight and inexpensive, especially in this compact form according to Fig. 3. In this design, it is ready to install and can also be used as a replacement part and quickly and inexpensively exchanged for an existing part. The particular advantage of this temperature control device 211 is that this arrangement enables very rapid adjustment of the control valve 220 depending on any other parameters or

Parameters are possible, whereby there is no need to fear that the control valve 220 will only slowly return to its original position after such an adjustment. Since the coolant in the line 217 is used to return the actuating element 250, very rapid recooling and thus very rapid resetting of the control valve 220 is ensured.

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Claims (3)

Expectations 1. Temperature control device for the coolant of internal combustion engines (10J^ with a supply line (15) leading from the internal combustion engine (10) to the cooler (12), a return line (17) leading from the cooler (12) back to the internal combustion engine (10) and a bypass line (19) connecting both lines (15, 17), with a control valve (20) regulating the coolant flow from the internal combustion engine (10) through the bypass line (19) and/or through the cooler (12) back to the internal combustion engine (10) and a servomotor (24) actuating the control valve (20) depending on the coolant temperature in one of the lines (15 or 17) connected to the internal combustion engine (10), the coolant temperature being detected by a sensor (27) in this line (15 or 17), characterized in that the sensor (27| 127 _f 250) with a heating device (29i 129> 229) or cooling device, by means of which the sensor (27| 1271 250) can be subjected to external heating or cooling depending on individual characteristics, in particular of the internal combustion engine (10« 110), e.g. its speed and/or its load, and accordingly via the servomotor -2- (24; 124; 250] the control valve [20, 120, 220) can be actuated in the direction of reducing or increasing the coolant temperature. 5 ! 2. Temperature control device according to claim 1, since characterized in that the sensor (27; 127, 250) has a heating device (C29, 129; 229) for external heating. P, 3. Temperature control device according to claim 1 or 2, &rgr;- characterized in that the Heating device (29 _} 129; 229) on the outside of the sensor (27; 127; 250). 15 4. Temperature control device according to one of the claims 1-3, characterized in that the heating device (29, 129; 229) is arranged on a temperature-sensitive region of the sensor (27; 127; 258) located outside the line (15; 117; 217). 5. Temperature control device according to one of claims 1-4, characterized in that that the heating device (29, 129, 229) is an electric Zo cal heating element. 6. Temperature control device according to one of claims 1-5, characterized in that ₃ Q that the heating device (29, 129) is connected to a control device (26; 126) and is switched on and off by the control device (26, 126) as required depending on individual characteristic field variables. 36 ■ ■■ Il 'I II·· ·· · -3- . Temperature control device according to one of claims 1-B, characterized in that the sensor (27» 127» 250) is cooled when the heating device (29i 1291 229) is switched off by the coolant flow in the line (15j 117» 217), which is colder than the heating device and to which the remaining temperature-sensitive area of the sensor (27j 1271 250) is exposed. ö.. Temperature control device according to one of claims 1-7, characterized in that the sensor (27» 127) is connected via a control line (28j 128) to the control device (26j 126), which is connected via a control line to the servomotor (24i 124) for its activation, wherein the control device (26» 126) is supplied with additional characteristic field variables in addition to the coolant temperature detected by the sensor (27» 127). . Temperature control device according to one of claims 1-7, characterized in that the sensor is connected directly to the servomotor via a control line or a direct transmission element for the purpose of actuating the servomotor. 10. Temperature control device according to claim 9, characterized in that the sensor (127) is designed as a temperature-dependent operating actuating element. t · &bull; · I It tl4l.HI · &diams; · 11. Temperature control device according to claim 10, characterized in that the temperature-dependent operating actuating element is connected to the servomotor (124) in a force-transmitting manner by means of a transmitter, e.g. a pressure medium line, an actuating rod, a Bowden cable or the like. 12. Temperature control device according to one of claims 1 - 11, characterized in that the servomotor is designed as a temperature-dependent operating actuating element, in particular as a known expansion element, whose moving part, e.g. piston, is firmly connected to the valve rod (141; 241) of the control valve (120» 220) and moves it in a translational manner. 13. Temperature control device according to claims 10 and 12, characterized in that the sensor and the servomotor are combined to form a single temperature-dependent operating actuating element (250), in particular a known expansion element. 14. Temperature control device according to claim 13, characterized in that the temperature-dependent operating actuating element (250), in particular an expansion element, is arranged with a part of its sensing part (251) inside the one line (217) and with the remaining part (254) of its sensing part (251) is arranged outside the line (217) and carries the external heating device (229), in particular the electrical heating element, on this part (254) of the sensing part (251). · 1b. Temperature control device according to claim 14, characterized in that the temperature-dependent operating actuating element (250) is arranged coaxially to two valve seats (244, 245) in a housing (240) and thereby passes transversely through one line (217), _e.g. the return line (217) leading from the cooler to the internal combustion engine. ti, temperature control device according to claim 14 or 15, characterized in that the part of the return line (217) coming from the cooler runs approximately parallel to the part of the return line (217) leading to the internal combustion engine and opens into the housing (240) IB on one side of the one valve seat (244). 17. Temperature control device according to one of claims 14 - 16, characterized in that the bypass line (219) opens into the housing (240) approximately coaxially to the temperature-dependent operating actuating element (250) and forms a second valve seat (245) with the latter. 1Θ. Temperature control device according to one of claims 14-17, characterized in that the line containing the temperature-dependent operating actuating element (250), in particular the return line (217), opens into the housing (240) at a point (232) which lies between the first valve seat (244) and the second valve seat (245). 19. Temperature control device according to one of claims 12 - 16, characterized in that the control valve (220) has on its valve rod (241) a first valve closure member (242) which is associated with the first valve seat (244), and in III Il l5 J I · · ·· · 1 axially spaced therefrom carries a second valve closure member (243) which is associated with the second valve seat (245), wherein both valve closure members are on the axial area between the two valve seats &iacgr;244, 245} 5 store. 20. Temperature control device according to claim 19, characterized in that the valve closure members (242, 243) are each designed as valve plates.