EP2562378B1 - Strategy to operate a split coolant circuit - Google Patents

Description

The invention relates to a strategy for operating a separate coolant circuit of an internal combustion engine, wherein a cylinder head water jacket and an engine block water jacket is provided, wherein the separate coolant circuit comprises at least one pump, at least one radiator, at least one control element, at least one coolant outlet housing and at least one heater, and wherein the separate coolant circuit circulates a coolant.

It is known that it is expedient to allow the engine block and the cylinder head of the internal combustion engine to flow separately or at least predominantly separated from one another with a coolant of a coolant circuit. In this way, the cylinder head, which is thermally coupled above all with the combustion chamber wall, the intake air duct and the exhaust gas outlet and the engine block, which is thermally coupled above all with the friction points, can be cooled differently. By this so-called "split-cooling system" (separate coolant circuit) is to be achieved that in the warm-up phase of the engine, the cylinder head is cooled, the engine block is not yet to be cooled, so that the engine block out faster to the required operating temperature can be, d. H. Under separate cooling circuit are not two cooling circuits to understand, but it is meant a cooling circuit for an internal combustion engine, wherein the water jacket of the cylinder head is separated from the water jacket of the cylinder block by suitable means. In some designs, however, small leaks can be provided from the cylinder head water jacket to the cylinder block water jacket, the leakage quantities being so small that one can nevertheless speak of a separate cooling circuit.

The FR 2 860 833 A1 discloses a refrigeration cycle of an internal combustion engine having at least one cylinder head and a cylinder housing consisting of at least three cooling passages. The circuit comprises heat exchange means, a drive means for a heat exchange medium and at least one control means for the flow of the heat exchange medium through the cylinder head, the cylinder housing or the heat exchange means on. The refrigeration cycle has at least three independent passages for engine cooling, the first and second passages being disposed in the cylinder head and the third passage being disposed in the cylinder housing and the passages being independent of each other and including at least one inlet and one outlet, so as to allow independent flow of the heat exchange medium through each of the passages of the cylinder head and the cylinder housing. The FR 2 860 833 A1 discloses that three control means are provided to control various circulations of the heat exchange medium can. Of the control means in each case an inlet side and an outlet side is arranged. The third control means is connected to the respective other two control means.

The US 5,385,123 discloses a separate refrigerant circuit with a single thermostat, which is arranged in one embodiment in an outlet line of the outlet side of a cylinder head to a pump, the line opens inlet side in the cylinder head. From the outlet branch a bypass and a block line branch off, which opens in the cylinder block. The bypass leads to the pump. The thermostat is arranged in this embodiment in the branch of the three lines. During the warm-up phase, the thermostat closes the block line with the bypass fully open. When the thermostat is closed, the coolant flows through the bypass to the pump and from there into the cylinder head. As the coolant temperature rises, the thermostat gradually closes the bypass, so that the direct flow towards the pump is continuously reduced, and is completely interrupted when the bypass is fully closed. The coolant then flows from the cylinder head through the exhaust duct and the block duct into the cylinder block which is connected to a radiator and from there to the pump.

The EP 1 900 919 B1 or JP57176317 also deals with a split-cooling system.

In the DE 103 42 935 A1 z. For example, an internal combustion engine having a refrigeration cycle having at least a first coolant channel and at least one second coolant channel disclosed in parallel with the first coolant channel is disclosed. Next, the internal combustion engine, the coolant channels associated throttling means for influencing the coolant channels passing coolant flow, and a mechanically driven coolant pump for the circulation of the coolant through the coolant channels. Control means are provided which provide manipulated variables for the individual control of the throttling means.

The DE 195 24 424 A1 relates to a liquid cooling of an internal combustion engine with a cooling liquid flow through a cooling liquid circuit in which a cooling liquid flowed through by the cooling chamber of the internal combustion engine, a cooler for the cooling liquid, a cooling liquid circulating pump and a thermostatically controlled valve is provided which at a low coolant temperature, the cooling liquid flow through the cooling space of the internal combustion engine at a low coolant temperature reduces the coolant flow through the radiator below the value of the coolant flow through the cooling chamber of the internal combustion engine. However, it may also be provided a load sensor of the internal combustion engine, which counteracts the reduction of the cooling liquid flow through the cooling space of the internal combustion engine at a high load of the internal combustion engine. In addition, a heating heat exchanger connected to the cooling liquid circuit and an adjusting means may be provided which counteracts the reduction of the cooling liquid flow through the radiator when operating and / or increasing an operation of the heating heat exchanger.

The DE 102 61 070 A1 discloses a water jacket structure for a cylinder head and a cylinder block of an engine having a split cooling system adapted therein. The water jackets for the cylinder head and the cylinder block are respectively and independently formed with an inlet shared between the cylinder head and the cylinder block. Its cross-sectional area is reduced to the inside, wherein positions of two outlets are shifted to the cylinder head.

Also in the KR 1020040033579 A discloses a split-cooling system, wherein a thermostat housing is designed as a single object and at a rear End of the internal combustion engine is arranged. In the DE 101 27 219 A1 is disclosed a cooling system for an internal combustion engine with at least two rows of cylinders, in particular for a V-type engine.

The DE 102 19 481 A1 is concerned with an internal combustion engine with a cylinder crankcase and a cylinder head, with a cooling water circuit with a cylinder head between an inlet opening and an outlet opening extending formed first water jacket and a separately thereof in the cylinder crankcase between an inlet opening and an outlet opening extending second cooling water channel and with a in the Cooling water circuit arranged, common cooling water pump. A third cooling water channel connects the outlet opening of the first cooling water channel formed in the cylinder head with the inlet opening of the cooling water pump. A fourth cooling water channel connects the outlet opening of the cooling water pump to the inlet opening of the second cooling water channel formed in the cylinder crankcase for passing the cooling water from the first into the second cooling water channel.

Also the DE 196 28 542 A1 deals with a split-cooling system, wherein the cylinder head or the cylinder heads are cooled by a cooling water circuit, which runs only through the cylinder head and in which a cooling water pump is inserted.

Likewise, the DE 34 40 504 C2 with the split-cooling system or separate coolant circuits for a cylinder block and the engine block.

The EP 0 816 651 B1 addresses the problem of providing a device which can reduce the heat-up time of an exhaust line and at the same time quickly raise and maintain the temperature of the walls of the engine block at a low load to a sufficient value, in any case to improve the operating conditions of the engine in all operating conditions , For this purpose, the EP 0 816 651 B1 a device for the internal combustion engine, which has a cylinder block and a cylinder head, whose walls for defining a first part and a second thereof different part, and the same through these walls separate cooling circuit are designed.

The EP 1 239 129 A2 deals with a simple cooling system for cooling the internal combustion engine.

In the prior art, the advantages and design concepts of separate cooling circuits (split-cooling system) compared to a conventional coolant circuit have long been known. The disadvantage is that the coolant flow distribution between the cylinder head and the engine block water jacket in both phases (thermostat closed below 90 ° C, thermostat open above 90 ° C) is fixed, resulting in an unnecessarily high heat output and low heating of the engine block and the oil film along the Bushings leads. It is also known that a bypass branches off from the thermostat, which bypasses the radiator or the main cooler, so that coolant can flow past the radiator, so that it is not unnecessarily cooled, which is advantageous in the warm-up phase. For the bypass but space must be occupied, which is dimensioned extremely low in the engine compartment.

It is therefore an object of the invention to improve a strategy for operating a separate coolant circuit of the type mentioned above with simple means.

According to the invention, the solution of the problem is achieved by a strategy having the features of claim 1.

It is expedient if the arranged on the outlet housing control is formed of a thermostat and a separate proportional valve, wherein the thermostat is fluidically connected in parallel to the proportional valve, and wherein the proportional valve is a block water line to block water jacket, a heating line to the heater and a radiator line to the radiator and wherein the thermostat has a connection line to the radiator.

It is advantageous that the coolant from the cylinder head water jacket can be passed directly into the block water jacket, being dispensed with a hitherto conventional bypass line. The engine block water jacket thus assumes the function of the previous bypass line, namely bypassing the radiator, so that the coolant z. B. is not unnecessarily cooled in the warm-up phase of the internal combustion engine. This leads to higher material and oil temperatures, which reduces friction and thermal losses. The advantageous embodiment of the coolant circuit according to the invention combines the advantages of the separate coolant circuit (rapid warm-up), whereby the fuel consumption and the generation of harmful emissions are significantly reduced, but also the life of the internal combustion engine is extended or increased.

The coolant circuit advantageously has an opposing coolant flow in the two separate cooling regions (cylinder head water jacket / block water jacket). In the cylinder head water jacket, the refrigerant flows from the inlet side to the outlet side, which is known per se. The block water jacket, however, the coolant is supplied to the side, which corresponds to the outlet side of the cylinder head water jacket. The coolant flows in the block water jacket, based on the flow direction in the cylinder head water jacket so almost inverted from the outlet side to the inlet side. Of course, the block water jacket has no flow contact, or coolant to the cylinder head water jacket, of course, small leakage quantities can not be excluded, as mentioned in the introduction. This means in the context of the invention that coolant from the block water jacket does not enter directly into the cylinder head water jacket, and both water jackets are quasi connected in series, but are flowed through in opposite directions.

It is expedient in the context of the invention if a pump line connects the pump to the inlet side of the cylinder head water jacket. The coolant can thus get out of the cylinder head water jacket in the outlet housing. From the proportional valve branches off the heating line, which leads to the heater. The heating return flows in front of the pump in a radiator return, which opens into the pump. The leading from the block water jacket return water pipe also opens in the radiator return also upstream of the pump. The from the On the other hand, a thermostatically-conducting connecting pipe advantageously flows in the cylinder head water pipe upstream of the radiator. Other components of the coolant circuit can be provided. For example, a ventilation device can be provided, which communicates with the heating line and the radiator, and whose return line also opens upstream of the pump in the radiator return.

Conveniently, the thermostat, which acts as a partial load thermostat, connected via the connecting line to the radiator, wherein the connecting line preferably upstream of the radiator but downstream of the proportional valve in the radiator line opens, the engine block water jacket conveniently, the radiator opens all around directly in the radiator return.

Target is when the control, so the proportional valve and the thermostat depending on operating modes of the engine such. B. of a warm-up phase of the internal combustion engine and a "warm" internal combustion engine are switchable, wherein the two components are still switchable depending on the presence of a partial load or a high load of the internal combustion engine. In this respect, quasi four modes of operation, which influence the control characteristics.

In a warm-up phase of the combustion engine operated at partial load, all paths of the proportional valve, ie the path to the block water line, the path to the heating line and the path to the radiator line of the proportional valve and the thermostat to the connecting line are closed. In this state, the separate coolant circuit quasi a zero flow amount, both in the block water jacket and in the headwater jacket. The coolant temperature is less than 60 ° C.

If the coolant temperature is more than 60 ° C and less than 75 ° C, the path of the proportional valve to the heater line opens continuously until it is fully open. The no-flow strategy of the cylinder head water jacket is abandoned, a partial flow of the coolant flows from the outlet housing via the proportional valve in the heating line. The path to the block water pipe is still closed, so that the coolant flow in the block water jacket has an amount of zero. Through the cylinder head water jacket flows only the amount that can flow through the heating line. In this respect, the coolant flow in the cylinder head water jacket is rather low, which benefits an improved warm-up behavior. Nevertheless, the heater can heat the vehicle cabin sufficiently.

If the coolant temperature has an amount of 75 ° C and less than 85 ° C, the path to the heater line is fully open, the path to the block water line opens continuously. In the block water jacket, a small flow of coolant is now made possible by the now-flow strategy. The path to the radiator line is still closed.

If the coolant temperature is greater than 85 ° C and less than 100 ° C, the path to the heater line is still fully open. The path to the block water line, however, is controlled via the proportional valve so that the block temperature can be adjusted to a high amount, for example to above 105 ° C, preferably to about 115 ° C. The thermostat also closes the path to the connecting line when the coolant temperature in the outlet housing or in the cylinder head water jacket below z. B. 100 ° C or preferably below 105 ° C.

If the warm-up phase is completed, the control components can now be controlled depending on the operating state "operating engine and part load".

In this mode, ie at a warm, operated under partial load internal combustion engine, the path to the heating line is opened, the path to the block water pipe is regulated, so that the block water temperature to a high amount of z. B. 115 ° C einregelbar. If the coolant in the cylinder head water jacket or in the outlet housing has an amount of more than 100 ° C, the thermostat opens to the connecting line. The coolant flow in the cylinder head water jacket is thus further increased. Characterized in that now an additional portion of the cylinder head coolant flow is passed over the main radiator, the temperature in the cylinder head water jacket is light, preferably adjustable below the opening temperature. The coolant flow is advantageously by means of Thermostats (opening temperature eg 100 ° C) controlled together with the proportional valve when the internal combustion engine has its operating temperature and is operated at partial load. The thermostat is thus preferably designed as a partial load thermostat, and only opens in partial load operation when the temperature in the cylinder head water jacket or in the outlet housing has an amount above the opening temperature.

In part-load operation, the internal combustion engine can thus be operated independently in both areas with elevated temperature.

Of course, the path of the proportional valve to the radiator line can be opened if necessary, if z. B. the internal combustion engine is operated at a higher load. For this purpose, the proportional valve opens the line to the main cooler to the temperature of the cylinder head water jacket on z. B. 85 ° C to regulate. The partial load thermostat is then closed because the opening temperature is not reached. The branch to the water jacket is then fully open. It is preferably provided to regulate the path so that the coolant temperature in the block water jacket is low, for example, is controlled to an amount of 90 ° C, since the cylinder block at higher load of the internal combustion engine has a higher cooling demand.

In the case of a malfunction of the proportional valve and thus an insufficient coolant flow to the main cooler, the part-load thermostat also has a protective function. In this case, as the coolant temperature rises above the opening temperature, the part load thermostat would open and direct coolant to the main radiator. The partial load thermostat can thus also act as a safety thermostat, as excessive overheating is avoided by opening to the radiator.

Another operating state or operating mode is when the internal combustion engine is operated in the warm-up phase at high load. In this mode of operation, it is advantageously provided that the path to the heating line is completely open, whereby the path to the block water line can also be regulated via the proportional valve. It is preferably provided to regulate the path so that the coolant temperature in the block water jacket is low, for example, regulated to an amount of 90 ° C. is because the cylinder block at full load of the engine requires high cooling. The coolant flow in the cylinder head water jacket is controlled via the proportional valve, whereby a temperature of 85 ° C can be controlled in the cylinder head water jacket.

Another mode is when the internal combustion engine has its operating temperature and is operated under high load or full load. In this mode, the path to the heating line can be closed. This is useful if z. B. at high outside temperatures, the largest cooling capacity to be generated. The path to the block water line can be controlled via the proportional valve. It is preferably provided to regulate the path so that the coolant temperature in the block water jacket is low, for example, regulated to an amount of 90 ° C, since the cylinder block at high load or at full load of the engine high cooling needs. The coolant flow in the cylinder head water jacket is controlled via the proportional valve, whereby a temperature of 85 ° C can be controlled in the cylinder head water jacket. Accordingly, the partial load thermostat will not open at all because the temperature is below its opening temperature. If the temperature still rises above the opening temperature, of course, opens the thermostat and takes over its protective function by coolant is passed in addition to the radiator.

Targeting in the sense of the invention is therefore when the control or the two components proportional valve and part load thermostat are controlled depending on the mode, which is conceivable with respect to the proportional valve by means of a control unit. Of course, the control strategy can also be stored in the central control unit of the internal combustion engine or of the motor vehicle.

With the coolant circuit according to the invention, the entire internal combustion engine, that is to say the block water jacket but also the head water jacket, can be operated with the no-flow strategy, if only for a short time, for a sufficiently long time. Despite the separation of the two coolant jackets from each other, the cabin heater can be powered by the appropriate path of the Proportional valve is opened. The no-flow strategy of the headwater jacket is given up, but maintained beneficial in the block water jacket.

The coolant inlet temperature to the block is also increased by about 3 to 5 K, since the feed from the output of the cylinder head circuit. Furthermore, the block temperature, ie the material temperature itself, can also be increased, since the temperature is controlled by means of the partial load thermostat, and a reduced flow of coolant through the block water jacket can be generated. It is also leading that in the cylinder head water jacket, a variable operating temperature is adjustable depending on the above-mentioned modes. The temperature can even be raised up to 115 ° C at partial load, when this temperature is exceeded, the part-load thermostat opens, thus increasing the flow of refrigerant and transferring part of it through the radiator. The coolant flow through the heater is variable during the warm-up phase. In particular, it is expedient that the coolant flow in the block water jacket is opposite to the coolant flow in the cylinder head water jacket. The fact that quasi-warmed coolant exiting from the cylinder head is also supplied to the block water jacket is advantageous with regard to the thermal management of the cylinder block, since inter alia frictional losses can be reduced.

It is expedient according to the invention, however, that only a partial flow of the coolant flowing through the cylinder head water jacket flows via the proportional valve into the block water jacket. This is advantageous because the necessary cooling capacity of the cylinder block corresponds to only about 30 to 50% of the cooling capacity of the cylinder head. By controlling the flow of coolant so the cylinder block temperature can be varied. The fact that not all of the coolant flow is passed over the radiator can be compensated for by closing the heating circuit, since the maximum cooling capacity on the vehicle radiator must be provided only at high outside temperatures. The cabin heater is then inactive. This leads to a change in the pressure conditions and thus to higher flow through the main cooler.

Due to the inventive design of the separate coolant circuit in which the thermostat allows the coolant flow through the radiator only at partial load of the engine or for protection purposes, the thermostat can be advantageously designed as a single-acting thermostat, which opens at relatively high temperatures, so increased coolant temperatures in particular Cylinder head water jacket to allow, in other deviating modes, the cylinder head coolant temperature is reduced, that is variable.

Fig. 1

eine Prinzipskizze eines getrennten Kühlmittelkreislaufes gemäß der Erfindung, und

Fig. 2

ein Diagramm zur beispielhaften Steuerung des Steuerelementes.

Further advantageous embodiments of the invention are disclosed in the subclaims and the following description of the figures. Show it

Fig. 1

a schematic diagram of a separate refrigerant circuit according to the invention, and

Fig. 2

a diagram for exemplary control of the control.

A separate coolant circuit 1 is in the FIG. 1 shown. The separate coolant circuit 1 has both a cylinder head water jacket 2 and an engine block water jacket 3, a pump 4, a radiator 6, a control element 7, a coolant outlet housing 8 and a heater 9. Furthermore, the coolant circuit 1 may have a degassing device 11.

The cylinder head water jacket 2 is separated from the block water jacket 3, so that there is a separate coolant circuit 1 in which a coolant circulates. The flow direction of the coolant is marked with corresponding arrows.

The arranged on the outlet housing 8 control 7 is formed of a thermostat 12 and a proportional valve 13 separate therefrom, wherein the thermostat 12 is arranged parallel to the proportional valve 13, and wherein the proportional valve a block water line 14 to the block water jacket 3, a heating line 16 to the heater 9 and a radiator line 17 to the radiator 6, and wherein the thermostat 12 has a connection line 18 to the radiator.

A pump line 19 connects the pump 4 to the inlet side 21 of the cylinder head water jacket 2. The coolant can thus pass from the cylinder head water jacket 2 into the outlet housing 8. The heating return 22 opens in front of the pump 4 in a radiator return 23, which opens into the pump 4. The leading from the block water jacket 3 return water line 24 also opens into the radiator return 23 also upstream of the pump 4. The leading from the thermostat 12 connecting line 18, however, opens advantageously in the radiator line 17 upstream of the radiator 6. The vent is connected to the heating line 16 and the radiator 6 in connection, wherein the return line 26 also opens upstream of the pump 4 in the radiator return 23.

The aim of the invention is that can be dispensed with a bypass line. The function of the bypass line takes over virtually the engine block water jacket 3. This is coolant, depending on operating modes of the internal combustion engine, supplied from the cylinder head water jacket 2 outflowing. It can be seen that the coolant flow in the block water jacket 3 is opposite to the coolant flow in the cylinder head water jacket 2.

The coolant is supplied to the block water jacket 3, based on the flow direction in the cylinder head water jacket 2 outlet side. The coolant flows through the block water jacket 3 in opposite directions to the flow direction in the cylinder head water jacket 2 and, based on the flow of coolant in the cylinder head water jacket 2 on the inlet side, and flows into the radiator return 23rd

The coolant temperature can be controlled or controlled by means of the proportional valve depending on operating modes. At partial load operation of the internal combustion engine, the coolant temperature in the cylinder head water jacket 2 is controlled by means of the thermostat 12. For example, the thermostat 12 may have an opening temperature of 100 ° C or even 115 ° C or an amount therebetween, so that the coolant temperature in the cylinder head water jacket is adjustable to this increased amount. At full load of the internal combustion engine, it is more advantageous to set the coolant temperature in the cylinder head water jacket to about 85 ° C, and in the block water jacket a low temperature of about 90 ° C. The Thermostat does not open at these low temperatures, so that the coolant temperature is controlled solely by the proportional valve. The modes of operation and the temperature control have already been described above, and become the preferred embodiment in their entirety.

FIG. 2 merely shows by way of example a diagram in which the coolant flows are represented by the heater (line 27), by the engine block water jacket (line 28) and by the radiator (line 29). On the vertical axis, the flow rate in I / min is plotted. On the horizontal, the opening of the proportional valve 13 is plotted in%.

In a first phase 31, the flow rate in all lines and the two water jackets 2 and 3 has a magnitude of zero (no-flow strategy).

In a second phase 32, coolant is increasingly flowing to the heater 9. The coolant flows in the engine block water jacket 3 and in the cooler 6 are ZERO (no-flow strategy in the block). There is low coolant flow in the cylinder head water jacket. The proportional valve 13 opens the heating line continuously until the path is fully opened. This corresponds to a total opening degree of up to 30% of the proportional valve 13.

In a third phase 33, the no-flow strategy is also abandoned in the block water jacket. The proportional valve opens this path continuously. The path to the radiator 6 is closed before. This is possible in partial load operation, so that the temperature control in the cylinder head water jacket takes place only via the partial load thermostat 12.

As can be seen, the flow rate in the engine block water jacket 3 increases from 0 up to 40 l / min, in which phase the flow through the heater decreases from 25 l / min to about 20 l / min. At the end of the third phase, the proportional valve is open approx. 50%, ie the path to the water jacket and to the heating is open. In partial load operation, it is quite sufficient to control the temperature in the cylinder head water jacket only on the part load thermostat and on a high level. When this "limit temperature" is reached, the part-load thermostat opens to the radiator.

If it is now recognized that no partial load of the internal combustion engine is present, but full load, the cylinder head coolant temperature is controlled in a fourth phase 34 to an amount of about 85 ° C. The proportional valve 13 opens the path to the radiator continuously, so that it is flowed through with up to 120 / min. The path to the heater can be closed.

The stated values for the limit temperatures and for the coolant flow rates of the proportional valve are, of course, only to be understood as examples and serve merely as exemplary guide values which should by no means be limiting. Rather, these values should be determined during engine development but not finalized.

The term "essentially" or "approximately" or "approx." means for the purposes of the invention deviations from the respective exact value by +/- 10%, preferably by +/- 5% and / or deviations in the form of insignificant for the function changes. The technical terms "partial load" and "full load" are as well known in the art as the terms "warm-up phase" and "operating warm".

Claims (7)

1. Strategy for operating a split coolant circuit (1) of an internal combustion engine, wherein a cylinder head water jacket (2) and an engine block water jacket (3) are provided, wherein the split coolant circuit (1) has a pump (4), a cooler (6), a control element (7), an outlet housing (8) and a heater (9), and wherein a coolant circulates in the split coolant circuit (1),
   wherein
   the control element (7) is formed from a thermostat (12) and a proportional valve (13) which is separate from said thermostat, said thermostat and proportional valve being arranged, connected in parallel, on the outlet housing (8), wherein coolant passing through the proportional valve (13) is conducted via a block water line (14) to the engine block water jacket (3), via a heater line (16) to the heater (9) and via a cooler line (17) to the cooler (6), wherein coolant passing through the thermostat (12) is conducted via a connecting line (18) to the cooler (6), wherein the thermostat (12) and the proportional valve (13) effect a coolant flow through the respective line (14, 16, 17, 18) independently of one another but as a function of operating modes (31, 32, 33, 34) of an internal combustion engine.
2. Strategy according to Claim 1,
   comprising
   the detection of a warm-up phase of the internal combustion engine at part load thereof, wherein initially all of the paths of the proportional valve (13) and also of the thermostat (12) are closed, such that a coolant flow of zero magnitude is present both in the block water jacket and also in the cylinder head water jacket.
3. Strategy according to Claim 1 or 2,
   comprising
   the detection of a warm-up phase of the internal combustion engine at part load thereof, wherein the path of the proportional valve (13) to the heater line (16) is opened, but the other paths of the proportional valve (13) and also of the thermostat (12) are closed, such that a coolant flow of zero magnitude is present in the block water jacket and a coolant flow is present in the cylinder head water jacket (2).
4. Strategy according to one of the preceding claims,
   comprising
   the detection of a warm-up phase of the internal combustion engine at part load thereof, wherein the path of the proportional valve (13) to the heater line (16) is opened and the path to the block water line (14) is opened, such that coolant passing out of the cylinder head enters into the block water jacket (3), wherein the other path of the proportional valve (13) and also of the thermostat (12) is closed, such that a coolant flow is present both in the block water jacket (3) and also in the cylinder head water jacket (2).
5. Strategy according to one of the preceding claims,
   comprising
   the detection of an internal combustion engine which is at operating temperature and which is being operated at part load, wherein the path to the heater line is opened and the path to the block water line (14) is regulated such that an elevated temperature of approximately 115°C is set in the block water jacket (3), wherein the thermostat (12), when its threshold temperature of for example 100°C is exceeded, opens such that the coolant flow in the cylinder head water jacket (2) is increased such that coolant also flows through the cooler (6).
6. Strategy according to one of the preceding claims,
   comprising
   the detection of an internal combustion engine which is warming up and which is being operated at full load, wherein the path to the heater line (16) is fully opened and the path to the block water line (14) is regulated such that a temperature of approximately 90°C is set in the block water jacket (3).
7. Strategy according to one of the preceding claims,
   comprising
   the detection of an internal combustion engine which is at operating temperature and which is being operated at full load, wherein the path to the heater line (16) is closed, and wherein the path to the block water line (14) can be regulated in terms of its flow rate by means of the proportional valve (13) such that a temperature of approximately 90°C is set in the block water jacket (3), wherein a temperature of approximately 85°C can be set in the cylinder head water jacket (2).

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