COOLING SYSTEM FOR A COMBUSTION ENGINE, COMBUSTION ENGINE AND MOTOR VEHICLE WITH A COMBUSTION ENGINE

Abstract

A cooling system is provided for a combustion engine having at least one pressure sensor and a diaphragm. The diaphragm is impermeable to a coolant of the cooling system and in contact with the coolant on a first side. A sensor device of the at least one pressure sensor is arranged separated from the coolant on a second side of the diaphragm located opposite the first side and configured to determine a pressure of the coolant.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to German Patent Application No. 102010048859.3, filed Oct. 19, 2010, which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The technical field relates to a cooling system for a combustion engine, a combustion engine with a cooling system and a motor vehicle with a combustion engine.

BACKGROUND

From U.S. Pat. No. 5,184,514 a pressure insulating device having a body of a first metallic material is known. The pressure insulating device additionally comprises a thin flexible diaphragm of a second metallic material, which cannot be connected to the first metallic material through direct welding. Furthermore, the pressure insulating device comprises a support ring of the same material as the diaphragm, which is mounted on the body, which surrounds an insulating opening. In addition to this, the pressure insulating device comprises a ring-shaped weld ring which is produced from the same material as the diaphragm and lies on a circumferential edge of the diaphragm and of the support ring and comprises a ring-shaped circumferential weld seam.

The circumferential weld seam runs through the weld ring, in order to seal and interconnect the support ring, the diaphragm and the weld ring about the circumference of the diaphragm, in order to create a sealed hollow space relative to the body and to the insulating opening. The weld ring forms a ring-shaped hollow space that lies on the diaphragm and comprises a basic wall through which the weld seam runs, and walls, which extend from the basic wall that defines a ring-shaped recess in order to receive a ring-shaped compressible seal for a process fluid connection.

In view of the foregoing, at least one object is to state a cooling system for a combustion engine, a combustion engine with a cooling system and a motor vehicle with a combustion engine, which make possible improved control or diagnosis possibilities of the cooling system in a simple manner. In addition, other objects, desirable features and characteristics will become apparent from the subsequent summary and detailed description, and the appended claims, taken in conjunction with the accompanying drawings and this background.

SUMMARY

According to an embodiment, the cooling system for a combustion engine comprises a pressure sensor and a diaphragm. The diaphragm is impermeable to a coolant of the cooling system. Furthermore, the diaphragm is in contact with the coolant on a first side. A sensor device of the at least one pressure sensor is arranged separated from the coolant on a second side of the diaphragm located opposite the first side and designed for determining a pressure of the coolant.

The cooling system makes possible the provision of improved control or diagnosis possibilities through the provision of at least one pressure sensor. The application starts out from the consideration that the knowledge of the pressure of the coolant on the one hand provides expanded possibilities for the temperature control of the cooling system. Furthermore, the knowledge of the pressure of the coolant or a temporal course of the pressure of the coolant makes possible expanded diagnostic functions for the cooling system. In this respect, the cooling system has the advantage that through the provision of the diaphragm that is impermeable the coolant and the arrangement of the sensor device in such a manner that it is separated from the coolant, pressure sensors can be employed in the cooling system whose sensor devices are not intended for the use in such a hot and wet environment.

As a result, cost-effective pressure sensors or sensor devices for the cooling system can be used in particular, which are already employed in additional components of the combustion engine. For example, a sensor that is employed in intake lines of the combustion engine or in charge pressure lines with a charged combustion engine, i.e. in substantially dry, gaseous environments, can be used as pressure sensor for the cooling system. Compared with other pressure sensors, this advantageously leads to a reduction of the development costs or development and validation time. In addition, fewer different replacement parts for the combustion engine have to be kept in stock.

In an embodiment the diaphragm comprises a material with a melting temperature T_S,M, where T_S,M>approximately 150° C. and preferably T_S,M>approximately 200° C. In this respect, the melting temperature is based on the normal pressure. Based on the generally merely low pressure dependency of the melting temperature the mentioned value is substantially unchanged for the further pressure values that typically prevail in the cooling system. In this respect the material can comprise tantalum or a tantalum alloy or hydrogenated acrylonitrile butadiene rubber (HNBR). The mentioned embodiments have the advantage that the diaphragm is designed particularly heat-resistant because of this.

In a further embodiment, the sensor device comprises a semi-conductor pressure sensor chip. Such sensor chips are more preferably used in the motor vehicle sector and thus have the advantage that they cover the measuring ranges that are typical for such applications. Preferably, the at least one pressure sensor additionally comprises a housing with an opening. The sensor device is arranged in the opening of the housing and the diaphragm covers the opening. This makes possible a particularly simple arrangement of the diaphragm on the pressure sensor.

In a further embodiment the housing in this respect comprises a material with a melting temperature T_S,G, where T_S,G>approximately 150° C. and further preferably T_S,G>approximately 200° C. In this respect, especially those regions of the housing that are in contact with the coolant preferably includes such a material. Because of this, the housing is advantageously adapted to the high ambient temperatures.

The material is preferably selected from the group consisting of polyphenylene sulfide and polybutylene terephtalate. The two mentioned substances form high-temperature resistant thermoplastics and because of this are particularly suited as housing material, even with a continuous use under high temperatures. In addition, the mentioned substances advantageously comprise a high chemical resistance and are thus particularly suited for a long-term use.

The diaphragm can be connected to the housing by means of an adhesive. This makes possible a simple fastening of the diaphragm to the housing. As suitable materials, the adhesive comprises for example fluorosilicone resin or fluoride resin. In a further embodiment, the diaphragm is connected to the housing by means of a screw connection. Preferably an O-ring seal is provided between the diaphragm and the housing. Furthermore, upon suitable material selection of the diaphragm and of the housing, the diaphragm can be connected to the housing by means of a soldering or welding connection.

Here, in a further embodiment a fluid is arranged between the diaphragm and the sensor device. A pressure exerted by the coolant on the first side of the diaphragm is transmitted to the sensor device by means of the fluid. Here, the fluid is preferably a gas, wherein the gas is for example formed through the ambient air. Because of this, sensor devices in turn can be advantageously provided for the at least one pressure sensor, which are provided for a use in a gas atmosphere.

In a preferred embodiment a characteristic curve of the sensor device is corrected for pressure dampening effects of the diaphragm. Typically, this is affected in that a pressure reduction caused by the diaphragm is incorporated in the characteristic curve. Such pressure dampening effects of the diaphragm in this respect are preferably determined even before an installation of the pressure sensor in the cooling system and the characteristic curve suitably corrected. Because of this, the actual pressure of the coolant can be advantageously determined as accurately as possible. The characteristic curve of the sensor device in this respect can for example be stored in a storage device that is part of an engine control device of the combustion engine.

In an embodiment, the at least one pressure sensor is arranged in an expansion tank of the cooling system. Because of this, the installation expenditure for the pressure sensor is advantageously very low. In a further embodiment the at least one pressure sensor is arranged on an output side of a coolant pump of the cooling system. Preferably, the at least one pressure sensor in this respect is arranged on an exhaust side of the combustion engine. The at least one pressure sensor is thus arranged on a high-pressure side of the coolant pump of the cooling system. This has the advantage that the pressure of the coolant can be determined on the outlet side of the coolant pump, as a result of which further control possibilities for the cooling system can be provided. To this end, the coolant pump can be preferably actuated by a control device, wherein the control device is in operational connection with the at least one pressure sensor.

A combustion engine is also provided that has a cooling system according to any one of the mentioned embodiments. The combustion engine in this respect is typically designed as liquid-cooled combustion engine. Furthermore, the application relates to a motor vehicle having a combustion engine according to the mentioned embodiments. In this respect, the motor vehicle is typically a passenger car or a commercial vehicle. The combustion engine and the motor vehicle according to the application have the advantages already mentioned in connection with the cooling system according to the application, which are not stated again at this point to avoid repetitions.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and:

FIG. 1 shows a motor vehicle with a combustion engine according to the embodiment;

FIG. 2 shows a cooling system according to a first embodiment for the combustion engine according to FIG. 1;

FIG. 3 shows a cooling system according to a second embodiment for the combustion engine according to FIG. 1; and

FIG. 4 shows the pressure sensor of the cooling systems according to FIG. 2 and FIG. 3.

DETAILED DESCRIPTION

The following detailed description is merely exemplary in nature and is not intended to limit application and uses. Furthermore, there is no intention to be bound by any theory presented in the preceding background or summary or the following detailed description.

FIG. 1 shows a motor vehicle 15 with a combustion engine 2 according to an embodiment. The motor vehicle 15 in the shown embodiment is a passenger car and the combustion engine 2 is designed as liquid-cooled combustion engine. Further details are explained in more detail in connection with the following figures. To this end, FIG. 2 shows a cooling system 1 according to a first embodiment of the application for the combustion engine 2 according to FIG. 1.

The combustion engine 2 comprises an inlet side 37 and an exhaust side 38. On the exhaust side 38 of the combustion engine 2 a branch-off 19 is arranged, from which a coolant line 23 leads to a coolant radiator 18. From the coolant radiator 18 a further coolant line 24 leads to a thermostat valve 20 arranged on the inlet side 37. Here, the thermostat valve 20 in the embodiment shown comprises an expansion material element 21 for example containing wax, wherein by means of the expansion material element 21 an opening temperature of the thermostat valve 20 is determined In flow direction of a coolant of the cooling system 1 not shown in more detail behind the thermostat valve 20 a coolant line 39 leads to a coolant pump 12.

From the branch-off 19 a coolant line 22 additionally leads to a heater heat exchanger 17. From the heater heat exchanger 17 in turn a coolant line 25 leads to the inlet side 37. The coolant line 25 in this respect branches off into a coolant line 26 and a coolant line 27. The coolant line 27 leads to an expansion tank 10 of the cooling system 1. The inlet side 37 of the combustion engine 2 is additionally connected to the exhaust side 38 via a bypass channel in the form of a coolant line 28. The coolant line 28 in the shown embodiment is partly arranged in a crankcase 16 of the combustion engine 2. The region of the coolant line 28 running within the crankcase 16 in this respect is represented by interrupted lines. The coolant line 28 leads from the branch-off 19 to a junction 40. At the junction 40, the coolant line 28 and the coolant line 26 lead into each other. A coolant line 41 leads from the junction 40 to the coolant line 39.

The coolant which is not shown in more detail, coming from the inlet side 37, flows through the combustion engine 2. The respective flow direction of the coolant in this respect is shown by means of arrows in FIG. 2. In the shown embodiment, the cooling system 1 comprises a pressure sensor 3 which is arranged in the expansion tank 10 of the cooling system 1. The pressure sensor 3 in this respect can be arranged in the region of the expansion tank 10 with liquid coolant or in the region of the gaseous coolant. Further details of the pressure sensor 3 will be explained in more detail in connection with FIG. 4.

The pressure sensor 3 is connected to an evaluation device 30 via a signal line 32, which evaluation device is designed for evaluating the pressure values of the coolant determined by means of the pressure sensor 3. The evaluation device 30 in the embodiment shown is part of an engine control device 29 of the combustion engine 2.

Furthermore, the motor vehicle not shown in more detail in FIG. 2 comprises an output device 31, which is designed for outputting a warning message should the pressure of the coolant drop below a predetermined threshold value. In particular, the output device 31 can be designed for outputting a warning message if the pressure of the coolant should drop below a threshold value within a predetermined duration. To this end, the output device 31 is connected to the engine control device 29 via a signal line 33. Typically, the output device 31 is designed for outputting a visual and/or acoustic and/or haptic warning message.

For example, a warning message can be output in the event that an abrupt pressure loss of the coolant is determined Such a pressure loss can point to a leak in the cooling system 1, for example due to a fallen-off or burst coolant hose. By outputting the warning message the occupants of the motor vehicle, particularly the driver of the motor vehicle, can be timely alerted to this situation as a result of which damages to the combustion engine 2 can be prevented. Thus, in the embodiment shown, the use of the pressure sensor 3 in the cooling system 1 provides expanded fault diagnosis possibilities for the cooling system 1.

FIG. 3 shows a cooling system 1′ according to a second embodiment for the combustion engine 2 according to FIG. 1. Components with the same functions as in the preceding figures are marked with the same reference characters and are not explained in more detail in the following. In the shown embodiment, the cooling system 1′ in turn comprises a pressure sensor 3, wherein the pressure sensor 3 is arranged on an outlet side 11 of the coolant pump 12 of the cooling system 1′, i.e., on a high-pressure side of the coolant pump 12. In the embodiment shown, the pressure sensor 3 in this respect is arranged on the exhaust side 38 of the combustion engine 2.

The coolant pump 12, which additionally comprises an inlet side 13, can be actuated by a control device 14. The coolant pump 12 can for example be designed as electric coolant pump, i.e., as coolant pump having an electric motor driving it. Furthermore, the coolant pump 12 can be designed as belt-driven coolant pump having a clutch, for example a magnetic clutch, which is arranged between the coolant pump and a drive belt that is not shown in more detail. In the first mentioned case the electric motor and in the second mentioned case the clutch is connected to the control device 14, as a result of which the coolant pump 12 in each case can be switched on and off. Furthermore, an actuatable cover that is arranged on the suction opening of the coolant pump 12 can be provided.

In the embodiment shown, the control device 14 is part of the tension control device 29 of the combustion engine 2. In addition, the control device 14 is in operational connection with the pressure sensor 3. To this end, the pressure sensor is connected to the engine control device 29 via a signal line 43. In the mentioned embodiment, the use of the pressure sensor 3 in the cooling system 1′ thus makes possible the provision of expanded control functions of the engine control device 29 for the cooling system 1′. Further details of the pressure sensor 3 are explained in more detail in connection with the following figure.

In this respect, FIG. 4 shows the pressure sensor 3 of the cooling system 1 according to FIG. 2 and of the cooling system 1′ according to FIG. 3. The pressure sensor 3 comprises a sensor device 6, which is designed for determining a pressure of the coolant which is not shown in more detail of the respective cooling system. The sensor device 6 in this respect comprises a semi-conductor pressure sensor chip 44 in the shown embodiment, for example a silicon-based pressure sensor chip.

Typically, the sensor device 6 has a measuring range for an absolute pressure of up to approximately 250 kPa, preferably up to approximately 300 kPa and more preferably up to approximately 400 kPa, or a measuring range for the differential pressure between the pressure of the coolant and the ambient pressure of up to approximately 150 kPa, preferably up to approximately 200 kPa and more preferably up to approximately 300 kPa.

Furthermore, the pressure sensor 3 comprises a housing 8 with an opening 9. The sensor device 6 is arranged in the opening 9 of the housing 8. A diaphragm 4 covers the opening 9. The diaphragm 4 is impermeable to the coolant of the cooling system and is in contact with the coolant on a first side 5. On a second side 7 of the diaphragm 4 located opposite the first side 5 the sensor device 6 is arranged separated from the coolant and thus advantageously protected from the rough ambient conditions in the form of heat and moisture. The diaphragm 4 to this end comprises a material with a melting temperature T_S,M, wherein T_S,M>approximately 150° C., wherein more preferably T_S,M>approximately 200° C. applies. For example, the diaphragm 4 comprises tantalum or a tantalum alloy or hydrogenated acrylonitrile butadiene rubber (HNBR).

In the shown embodiment, the housing 8 additionally comprises a material with a melting temperature T_S,G, wherein T_S,G>approximately 150° C., more preferably T_S,G>approximately 200° C. applies. For example, the housing comprises polyphenylene sulfide and polybutylene terephtalate.

Between the diaphragm 4 and the sensor device 6 is located a fluid that is not shown in more detail, wherein this fluid in the embodiment shown is formed through the ambient air. A pressure exerted by the coolant on the first side 5 of the diaphragm 4 is transmitted to the sensor device 6 by means of the fluid.

A bond wire 35 connects the semi-conductor pressure sensor chip 44 to a connection line 34. Between the connection line 34 and the housing 8 sealing material 36 is arranged, as a result of which the sensor device 6 is protected from an entry of the coolant to a further increased degree.

Although at least an exemplary embodiment was shown in the preceding description, different changes and modifications can be carried out. The mentioned embodiments are merely examples and not intended to restrict the scope, the applicability or the configuration in any manner whatsoever. On the contrary, the preceding description at least makes available a plan for implementing at least one exemplary embodiment to the person skilled in the art, where numerous changes in the function and the arrangement of elements described in an exemplary embodiment can be made without leaving the scope of protection as set forth in the following claims.

Claims

1. A cooling system for a combustion engine, comprising:

a coolant;

a pressure sensor;

a diaphragm that is impermeable to the coolant and on a first side in contact with the coolant; and

a sensor device of the pressure sensor on a second side of the diaphragm located opposite the first side and arranged to separate from the coolant and configured to determine a pressure of the coolant.

2. The cooling system according to claim 1,

wherein the diaphragm comprises a material with a melting temperature TS,M, and

wherein TS,M>approximately 150° C.

3. The cooling system according to claim 2, wherein the material comprises tantalum.

4. The cooling system according to claim 2, wherein the material comprises a tantalum alloy.

5. The cooling system according to claim 2, wherein the material comprises a hydrogenated acrylonitrile butadiene rubber.

6. The cooling system according to claim 1, wherein the sensor device comprises a semi-conductor pressure sensor chip.

7. The cooling system according to claim 1,

wherein the pressure sensor further comprises a housing with an opening,

wherein the sensor device is arranged in the opening of the housing, and

wherein the diaphragm is configured to cover the opening.

8. The cooling system according to claim 7,

wherein the housing comprises a material with a melting temperate TS,G, and

wherein TS,G>approximately 150° C.

9. The cooling system according to claim 8, wherein the material comprises a polyphenylene sulfide.

10. The cooling system according to claim 8, wherein the material comprises a polybutylene terephtalate.

11. The cooling system according to claim 7, wherein the diaphragm is connected to the housing with an adhesive.

12. The cooling system according to claim 1, wherein a fluid is located between the diaphragm and the sensor device.

13. The cooling system according to claim 1, wherein a characteristic curve of the sensor device is corrected for pressure dampening effects of the diaphragm.

14. The cooling system according to claim 1, wherein the pressure sensor is arranged in an expansion tank.

15. The cooling system according to claim 1, wherein the pressure sensor is arranged on an outlet side of a coolant pump.

16. The cooling system according to claim 15,

wherein the coolant pump is configured to actuate by a control device, and

wherein the control device is operably connected with the pressure sensor.