LIQUID COOLING SYSTEM FOR AN INTERNAL COMBUSTION ENGINE OF A VEHICLE

Abstract

The invention relates to a liquid cooling system (K) for an internal combustion engine (2) of a vehicle with a cylinder head (3) having as integrated exhaust manifold (7), wherein the cylinder head (3) has at least a first cooling chamber (5) for cooling areas adjoining a combustion chamber and at least a second cooling chamber (6) for cooling the exhaust manifold (7), wherein flows can pass through the first and second cooling chambers (5, 6) in parallel separately from one another. The cooling management can be improved in a simple manner if at least one oil cooler (14) and/or at least one vehicle heating element (15) is arranged in series with the second cooling chamber (6) in the cooling circuit (1).

Description

The invention relates to a liquid cooling system for an internal combustion engine of a vehicle with a cylinder head comprising an integrated exhaust manifold, wherein the cylinder head has at least one first cooling space for cooling areas adjacent to a combustion chamber and at least one second cooling space for cooling the exhaust manifold, said first and second cooling spaces providing separate cooling flow paths in parallel.

From U.S. Pat. Nr. 2005/0087154 A1 it is known to integrate the exhaust manifold in the cylinder head. The main cooling space consisting of an upper and a lower partial cooling jacket is in thermal contact with the exhaust manifold.

EP 0 856 650 A1 describes a cooling system for an outboard engine where the exhaust ducts departing from the combustion chamber are curved in U-shape in the cylinder head, the flange areas for connecting the exhaust manifold being situated in the cylinder head plane. The exhaust manifold is integrated in the cylinder head.

U.S. Pat. No. 7,051,685 B2 discloses a cylinder head with integrated exhaust manifold, where the exhaust manifold is surrounded by a first and a second cooling jacket, the two cooling jackets being connected via flow paths cast together with the cylinder head. The first and second cooling jackets are positioned one above the other.

AT 500 442 B1 describes a cylinder head for an internal combustion engine with liquid cooling comprising a first central cooling space and a second cooling space surrounding an integrated exhaust manifold, where the coolant flow through the second cooling space may be controlled separately from the coolant flow through the first cooling space.

From WO 2011/061248 A1 there is known a cylinder head for an internal combustion engine with liquid cooling and with a liquid-cooled exhaust manifold integrated in the cylinder head, where the cylinder head has at least one first and one second cooling jacket through which coolant flows and where the region of the exhaust manifold is at least partially surrounded by the second cooling jacket. The first and second cooling jackets are flow-connected via at least one bore.

It is known to position the vehicle cooler and the oil cooler parallel to the cooling space of the exhaust manifold. In order to avoid cooling failures a relatively expensive cooling system is required.

It is an object of the present invention to improve the cooling management of an internal combustion engine of the initially mentioned kind in as simple a manner as possible.

According to the invention this object is achieved by proposing that at least one oil cooler and/or at least one vehicle heating element be arranged in series with the second cooling space in the cooling circuit.

The oil cooler may be positioned in the cooling circuit upstream of the second cooling space, while the vehicle heating element is positioned in the cooling circuit downstream of the second cooling space.

It is of particular advantage if a first partial cooling circuit leading to the first cooling space and a second partial cooling circuit leading to the second cooling space branch off the common main cooling circuit downstream of a coolant pump.

Upstream of the coolant pump in an area where a main cooling circuit coming from the coolant cooler and an auxiliary cooling circuit bypassing the coolant cooler meet, there may be provided a first double-acting thermostatic valve.

The first cooling space is preferably connected by a first coolant line with the auxiliary cooling circuit.

The second cooling space is advantageously connected via a second coolant line with the main cooling circuit and/or the auxiliary cooling circuit, the second coolant line preferably including a vehicle heating element.

It may furthermore be provided that at least one third cooling space located in the cylinder block be connected with the first cooling space in the cylinder head by means of at least one transfer passage. Preferably, the third cooling space is connected with the main cooling circuit via a third coolant line, the connection with the main cooling circuit being located upstream of the coolant cooler. In a variant of the invention it is provided that in the third coolant line there is located a single-acting thermostatic valve.

In another variant of the invention it is provided that the third cooling space be connected via a fourth coolant line with the auxiliary cooling circuit and/or the first coolant line. In the fourth coolant line there may be located a single-acting thermostatic valve. As an alternative it would also be possible to position a second double-acting thermostatic valve at the crossing site of the first coolant line and the fourth coolant line and the auxiliary cooling circuit.

The described variants permit a simple cooling management, the flow through the oil cooler and through the vehicle heating element having no negative effects.

The invention will now be described in more detail with reference to the enclosed drawings. There is shown in

FIG. 1 to FIG. 3 a first variant of a liquid cooling system for an internal combustion engine according to the invention;

FIG. 4 to FIG. 7 a second variant of a liquid cooling system for an internal combustion engine according to the invention;

FIG. 8 to FIG. 11 a third variant of a liquid cooling system for an internal combustion engine according to the invention; and in

FIG. 12 to FIG. 16 a fourth variant of a liquid cooling system for an internal combustion engine according to the invention.

In the drawings deactivated parts of the liquid cooling system K are indicated by broken lines. Parts of equivalent function bear identical reference numbers in each variant.

The drawings show in each case a liquid cooling system K with a cooling circuit 1 for a vehicle with an internal combustion engine 2 with cylinder head 3 and cylinder block 4, comprising at least one first cooling space 5 for cooling thermally critical areas adjacent to the combustion chamber and at least one second cooling space 6 for cooling the exhaust manifold 7 integrated in the cylinder head 3. At least one further cooling space 8 is provided in the cylinder block 4 for cooling the cylinders 9.

KM indicates that part of the cooling system K pertaining to the engine side, while KF indicates the part pertaining to the vehicle side.

In the cooling circuit 1 coolant flow in the first and second cooling space 5, 6 is hydraulically parallel, with a first partial cooling circuit 10 serving the first cooling space 5 and a second partial cooling circuit 11 serving the second cooling space 6. The first and second partial cooling circuits 10, 11 branch off a common main line 13 of the liquid cooling system K downstream of a coolant pump 12.

In the second partial cooling circuit 11 an oil cooler 14 is located upstream of the second cooling space 6 and a vehicle heating element 15 is located downstream of the second cooling space 6. The vehicle heating element 15 may be deactivated by means of a bypass valve, which is not shown in the drawings.

In the area 16 where the main cooling circuit 18 coming from the coolant cooler 17 is joined by an auxiliary cooling circuit 19 bypassing the coolant cooler 17, there is located a first double-acting thermostatic valve 20 upstream of the coolant pump 12.

In the first three variants of the invention the first and the third cooling space 5, 8 are connected via at least one transfer passage 21.

The second cooling space 6 is connected via a second coolant line 23 with the main cooling circuit 18 and/or with the auxiliary cooling circuit 19, the vehicle heating element 15 being located in the second coolant line 23. The third cooling space 8 is connected with main cooling circuit 18 via a third coolant line 24, the connection 25 to the main cooling circuit 18 being located upstream of the coolant cooler 17.

In the variants shown in FIGS. 1 to 3 there is provided only one thermostat, i.e. the first double-acting thermostatic valve 20. In FIG. 1 the first double-acting thermostatic valve 20 is shown in an intermediate position, in which both the main cooling circuit 18 and the auxiliary cooling circuit 19 are connected with the main line 13 containing the coolant pump 12. FIG. 2 shows the situation when the internal combustion engine is at operating temperature, the auxiliary cooling circuit 19 is deactivated and the entire coolant volume flows through the main cooling circuit 18.

FIG. 3 shows the liquid cooling system K in the cold state, with the main cooling circuit 18 deactivated and the entire coolant volume flowing through the auxiliary cooling circuit 19, bypassing the coolant cooler 17.

FIGS. 4 to 7 show a second variant of the invention with various switching possibilities, where in addition to the double-acting thermostatic valve 20 there is provided a single-acting thermostatic valve 26 in the third coolant line 24. Furthermore, the first cooling space 5 is connected with the auxiliary cooling circuit 19 via a first coolant line 22.

In FIG. 4 the first double-acting thermostatic valve 20 is in the intermediate position—in analogy to FIG. 1—and the single-acting thermostatic valve 26 is open. Thus coolant may flow unimpededly in the main cooling circuit 18 as well as in the auxiliary cooling circuit 19 and in the third coolant line 24. In contrast to the first variant the coolant may flow directly into the auxiliary cooling circuit 19 via the first coolant line 22.

FIG. 5 shows the situation when the internal combustion engine 2 is in the cold state, the main cooling circuit 18 being closed by the double-acting thermostatic valve 20. The entire coolant volume flows through the auxiliary cooling circuit 19, the coolant flowing directly into the auxiliary cooling circuit 19 via the first coolant line 22.

In FIG. 6 the internal combustion engine 2 is in the lower range of operational temperature, where the auxiliary cooling circuit 19 is closed by the first double-acting thermostatic valve 20 while the main cooling circuit 18 is open. Due to closing of the single-acting thermostatic valve 26 cooling of the cylinder block 4 is deactivated. The coolant flows through the first cooling space 5 into the first coolant line 22 and via the free part 19a of the auxiliary cooling circuit 19 into the main cooling circuit 18 upstream of the coolant cooler 17. In parallel therewith the coolant flows through the second partial cooling circuit 11, through the oil cooler 14, the second cooling space 6 and the vehicle heating element 15, and will arrive at the coolant cooler 17 after having joined the coolant flow from the first partial cooling circuit 10.

FIG. 7 differs from FIG. 6 by the single-acting thermostatic valve 26 now being open such that cooling of the cylinder block 4 is being activated as required in the medium to hot operational temperature range of the internal combustion engine 2. The coolant flows from the cylinder head 3 via transfer passages 21 into the third cooling jacket 8 and leaves the cylinder block 4 via the third coolant line 24 in the direction of main cooling circuit 18 to dissipate the absorbed heat in the coolant cooler 17.

FIGS. 8 to 11 show a third variant of the invention with various switching possibilities, where the third cooling jacket 8 is connected with the auxiliary cooling circuit 19 via a fourth coolant line 27 and with the first cooling space 5 via the first coolant line 22. In addition to the first double-acting thermostatic valve 20 there is provided a single-acting thermostatic valve 28 in the third coolant line 24. In this variant no transfer passages 21 are provided between the first and the third cooling space 5, 8, the function of these transfer passages being taken over by the first and fourth coolant line 22, 27.

In FIG. 8 the first double-acting thermostatic valve 20 is in its intermediate position—in analogy to FIGS. 1 and 4—while the single-acting thermostatic valve 28 is open. Thus coolant may flow unimpededly in the main cooling circuit 18, as well as in the auxiliary cooling circuit 19 and in the third and fourth coolant line 24, 27. Unlike in the first variant the coolant may flow directly into the auxiliary cooling circuit 19 via the first coolant line 22, and may flow from the auxiliary cooling circuit 19 into the third cooling space 8 via the fourth coolant line 27.

FIG. 9 shows the situation when the internal combustion engine 2 is in the cold state: the main cooling circuit 18 is closed by the double-acting thermostatic valve 20 and the whole coolant volume is directed through the auxiliary cooling circuit 19, flowing directly into the auxiliary cooling circuit 19 via the first coolant line 22. The single-acting thermostatic valve 28 is closed and inhibits flow into the first cooling space 8.

In FIG. 10 the internal combustion engine is shown in the lower operational temperature range—analogous to FIG. 6—where the auxiliary cooling circuit 19 is closed by the first double-acting thermostatic valve 20 and the main cooling circuit 18 is open. Due to closing of the single-acting thermostatic valve 28 cooling of the cylinder block 4 is deactivated. The coolant thus flows through the first cooling space 5 into the first coolant line 22 and reaches via the free part 19a of the auxiliary cooling circuit 19 the main cooling circuit 18 upstream of the coolant cooler 17. In parallel therewith the coolant flows through the second partial cooling circuit 11, through the oil cooler 14, the second cooling space 6 and the vehicle heating element 15 and reaches the coolant cooler 17 after joining the coolant flow of the first partial cooling circuit 10.

In FIG. 11 the single-acting thermostatic valve 28 is now open, and cooling of the cylinder block 4 is thus activated in the medium to hot operational temperature range of the internal combustion engine 2. The coolant flows from the first cooling space 5 of the cylinder head 3 via the first and the fourth coolant line 22, 27 into the third cooling space 8 of the cylinder block 4 and leaves the cylinder block 4 via the third coolant line 24 directed towards the main cooling circuit 18 upstream of the coolant cooler 17.

FIGS. 12 to 16 show a fourth variant of the liquid cooling system K with various possibilities of switching. In a similar way as in the third variant the third cooling space 8 is connected with the auxiliary cooling circuit 19 via a fourth coolant line 27 and with the first cooling space 5 via the first coolant line 22. Instead of the single-acting thermostatic valve 28 there is now disposed, in addition to the first double-acting thermostatic valve 20, yet another double-acting thermostatic valve 29 at the crossing site 30 where the first and fourth coolant lines 22, 27 meet with the auxiliary cooling circuit 19. In this case no other transfer passages 21 are provided between the first and the third cooling space 5, 8; the function of transfer passages 21 is taken over by the first and fourth coolant lines 22, 27.

In FIG. 12 both double-acting thermostatic valves 20, 29 are in intermediate positions. The coolant can thus flow unimpededly in the main cooling circuit 18 as well as in the auxiliary cooling circuit 19 and in the third and fourth coolant line 24, 27. The coolant may flow via the first coolant line 22 directly into the auxiliary cooling circuit 19, or into the fourth coolant line 27 and from the auxiliary cooling circuit 19 via the fourth coolant line 27 into the third cooling space 8.

FIG. 13 shows the situation when the internal combustion engine 2 is in the cold state. The main cooling circuit 18 is closed by the first double-acting thermostatic valve 20—the whole coolant volume passes through the auxiliary cooling circuit 19. Furthermore, the first and fourth coolant lines 22, 27 are closed by the second double-acting thermostatic valve 29, and thus there is no coolant flow through the first cooling space 5 and the third cooling space 8. The coolant circulates only in the little circuit through the coolant line 11, the oil cooler 14, the second cooling space 6, the vehicle heating element 15 and the auxiliary cooling circuit 19.

When the operational temperature of the internal combustion engine 2 rises, the first coolant line 22 is opened by the second double-acting thermostatic valve 29, as shown in FIG. 14. This will enable coolant flow through the first cooling space 5 in the cylinder head 3, the coolant leaving the first cooling space 5 via the first coolant line 22 and flowing back to the coolant pump 12 via the auxiliary cooling circuit 19.

Upon a further increase of the temperature of the internal combustion engine 2 the auxiliary cooling circuit 19 leading to the coolant pump 12 is closed by the second double-acting thermostatic valve 29 between the crossing site 30 and the meeting area 16, as shown in FIG. 15. The coolant leaving the first cooling space 5 through the first coolant line 22 now flows through the free part 19a of the auxiliary cooling circuit 19 into the main cooling circuit 18 upstream of the coolant cooler 17.

FIG. 16 shows the liquid cooling system K at medium to hot operational temperature of the internal combustion engine 2. The first double-acting thermostatic valve 20 now closes the auxiliary cooling circuit 19 and opens the main cooling circuit 18. The second double-acting thermostatic valve 29 is in its intermediate position, in which the first and fourth coolant lines 22, 27 are open, permitting coolant to flow from the first coolant line 22 into the free part 19a of the auxiliary cooling circuit 19 as well as into the fourth coolant line 27. Thus the first and third cooling space 5, 8 will receive coolant flow. From the first cooling space 5 of the cylinder head 3 the coolant flows via the first and fourth coolant line 22, 27 into the third cooling space 8 of the cylinder block 4 and leaves the cylinder block 4 via the third coolant line 24 towards the main cooling circuit 18 upstream of the coolant cooler 17.

The oil cooler 14, the second cooling space 6 for cooling the exhaust manifold 7 and the vehicle heating element 15 will always receive coolant flow regardless of the positions of the thermostatic valves 20, 26, 28, 29.

Claims

1. A liquid cooling system for an internal combustion engine of a vehicle with a cylinder head comprising an integrated exhaust manifold, wherein the cylinder head has at least one first cooling space for cooling areas adjacent to a combustion chamber and at least one second cooling space for cooling the exhaust manifold, said first and second cooling spaces providing separate parallel cooling flow paths, wherein at least one oil cooler and/or at least one vehicle heating element is disposed in a cooling circuit in series with the second cooling space.

2. The liquid cooling system according to claim 1, wherein a first partial cooling circuit leading to the first cooling space and a second partial cooling circuit leading to the second cooling space branch off a common main line.

3. The liquid cooling system according to claim 2, wherein the oil cooler in the second partial cooling circuit is located upstream of the second cooling space.

4. The liquid cooling system according to claim 2, wherein the vehicle heating element in the second partial cooling circuit is located downstream of the second cooling space.

5. The liquid cooling system according to claim 1, wherein a first double-acting thermostatic valve is disposed upstream of the coolant pump in the area where a main cooling circuit coming from the coolant cooler and an auxiliary cooling circuit bypassing the coolant cooler meet.

6. The liquid cooling system according to claim 5, wherein the first cooling space is connected with the auxiliary cooling circuit by a first coolant line.

7. The liquid cooling system according to claim 5, wherein the second cooling space is connected with the main cooling circuit and/or the auxiliary cooling circuit by a second coolant line.

8. The liquid cooling system according to claim 1, wherein at least one third cooling space in the cylinder block is connected with the first cooling space in the cylinder head by means of at least one transfer passage.

9. The liquid cooling system according to claim 8, wherein the third cooling space is connected with the main cooling circuit by means of a third coolant line, the connection with the main cooling circuit being located upstream of the coolant cooler.

10. The liquid cooling system according to claim 9, wherein a single-acting thermostatic valve is disposed in the third coolant line.

11. The liquid cooling system according to claim 8, wherein the third cooling space is connected with the auxiliary cooling circuit and/or the first coolant line by means of a fourth coolant line.

12. The liquid cooling system according to claim 11, wherein a single-acting thermostatic valve is provided in the fourth coolant line.

13. The liquid cooling system according to claim 11, wherein at the crossing site of the first coolant line and the fourth coolant line and the auxiliary cooling circuit a second double-acting thermostatic valve is provided.

14. The liquid cooling system according to claim 2, wherein the first partial cooling circuit and the second partial cooling circuit branch of the common main line downstream of a coolant pump.

15. The liquid cooling system according to claim 7, wherein the vehicle heating element is located in the second coolant line.