Cooling system of an internal combustion engine of a motor vehicle

Abstract

An internal combustion engine of a motor vehicle is provided. The internal combustion engine includes a coolant, a liquid/gas heat exchanger, a coolant-temperature-dependent control element, an equalizing tank, fluidic connections between the components, and a coolant pump. At least one direct or at least one activation-dependent fluidic connection or at least one force-transmitting connection is set up between a medium in the equalizing tank and a medium of at least one other media path or media circuit of the motor vehicle.

Claims

1. A cooling system of an internal combustion engine of a motor vehicle, the cooling system comprising: a predetermined amount of coolant, at least one liquid/gas heat exchanger, at least one coolant-temperature-dependent control element, an equalizing tank for receiving some of the coolant in a coolant-temperature-dependent manner, connecting elements for producing fluidic connections, and a coolant pump, wherein at least one direct or at least one activation-dependent fluidic connection or at least one force-transmitting connection is set up between a medium in the equalizing tank and a medium of at least one other media path or media circuit of the motor vehicle, and wherein the connection set up between the medium in the equalizing tank and the medium of the at least one other media path or media circuit contains a pressure-transmission element having media separation or a fluid separator having a movable dividing wall or having a membrane.

2. The cooling system as claimed in claim 1, wherein the at least one other media path or media circuit is formed by an air intake region of the internal combustion engine.

3. The cooling system as claimed in claim 1, wherein the at least one other media path or media circuit is formed by an oil lubrication circuit of the motor vehicle.

4. The cooling system as claimed in claim 3, wherein the oil lubrication circuit of the motor vehicle has an oil pump which can be controlled by a characteristic map.

5. The cooling system as claimed in claim 1, wherein the connection set up between the medium in the equalizing tank and the medium of the at least one other media path or media circuit contains an activatable non-return valve which is permeable in the direction of the equalizing tank.

6. The cooling system as claimed in claim 1, wherein the connection set up between the medium in the equalizing tank and the medium of the at least one other media path or media circuit contains an electrically controllable valve.

7. The cooling system as claimed in claim 1, wherein the connection set up between the medium in the equalizing tank and the medium of the at least one other media path or media circuit contains a throttle valve for flow restriction.

8. The cooling system as claimed in claim 1, wherein the connection set up between the medium in the equalizing tank and the medium of the at least one other media path or media circuit contains a pressure-control valve for limiting the pressure in the equalizing tank.

9. The cooling system as claimed in claim 1, wherein the connection set up between the medium in the equalizing tank and the medium of the at least one other media path or media circuit contains a pressure intensifier for increasing pressure.

10. A cooling system of an internal combustion engine of a motor vehicle, the cooling system comprising: a predetermined amount of coolant, at least one liquid/gas heat exchanger, at least one coolant-temperature-dependent control element, an equalizing tank for receiving some of the coolant in a coolant-temperature-dependent manner, at least one force-transmitting connection, and a coolant pump, wherein, the at least one force-transmitting connection is set up between a medium in the equalizing tank and a medium of at least one other media path or media circuit of the motor vehicle; and wherein the force-transmitting connection set up between the medium in the equalizing tank and the medium of at least one other media path or media circuit contains a pressure intensifier for increasing pressure, and wherein the medium in the equalizing tank is formed by air under normal atmospheric pressure over the coolant and the medium of the at least one other media path or media circuit is lubricating oil circulating in an oil lubrication circuit.

11. The cooling system of claim 10, wherein the oil lubrication circuit comprises an oil pump controlled by a characteristic map.

12. The cooling system of claim 10, wherein the force-transmission connection comprises a fluid separator having a moveable dividing wall or membrane.

13. A cooling system of an internal combustion engine of a motor vehicle, the cooling system comprising: a predetermined amount of coolant, at least one liquid/gas heat exchanger, at least one coolant-temperature-dependent control element, an equalizing tank for receiving some of the coolant in a coolant-temperature-dependent manner, at least one force-transmitting connection, and a coolant pump, wherein, the at least one force-transmitting connection is set up between a medium in the equalizing tank and a medium of at least one other media path or media circuit of the motor vehicle; and wherein the force-transmitting connection set up between the medium in the equalizing tank and the medium of at least one other media path or media circuit contains a pressure intensifier for increasing pressure, wherein the force-transmitting connection contains a pressure-transmission element having media separation or comprises a fluid separator having a moveable dividing wall or membrane.

14. The cooling system of claim 13, wherein pressure is transmitted to a first side of the pressure-transmission element by a line filled with lubricating oil.

15. The cooling system of claim 14, wherein a second side of the pressure-transmission element is in fluidic connection with air in the equalizing tank.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) FIG. 1 is a schematic view of a conventional cooling system of an internal combustion engine of a motor vehicle, having split cooling.

(2) FIG. 2 is a schematic view of an embodiment of a cooling system according to the disclosure of an internal combustion engine of a motor vehicle, having split cooling.

(3) FIG. 3 is a schematic view of an embodiment of the cooling system according to FIG. 2, comprising an alternative fluidic connection between a medium in the equalizing tank and a medium of another media path.

(4) FIG. 4 is a schematic view of an embodiment of the cooling system according to FIG. 2, comprising another alternative fluidic connection.

(5) FIG. 5 is a schematic view of an embodiment of the cooling system according to FIG. 2, comprising another alternative fluidic connection.

(6) FIG. 6 is a schematic view of an embodiment of the cooling system according to FIG. 2, comprising a force-transmitting connection between a medium in the equalizing tank and a medium of another media path.

(7) FIG. 7 is a schematic view of an embodiment of the cooling system according to FIG. 2, comprising a force-transmitting connection between a medium in the equalizing tank and a medium of another media path.

(8) FIG. 8 is a schematic view of an embodiment of the cooling system according to FIG. 7, comprising a force-transmitting connection between a medium in the equalizing tank and a medium of another media circuit.

(9) FIG. 9 is a schematic view of a detail of the cooling system according to FIG. 8.

(10) FIG. 10 is a table having typical pressure values in a charged air intake region of the internal combustion engine according to FIG. 2 according to an operating load point of the internal combustion engine and a driving speed of the motor vehicle.

(11) FIG. 11 is a flow chart of a method for regulating pressure in an equalizing tank.

DETAILED DESCRIPTION

(12) The following description relates to systems and methods for regulating cavitation in the cooling system of an internal combustion engine of a motor vehicle. FIG. 1 is a schematic view of a conventional cooling system of an internal combustion engine 10 of a motor vehicle, having a split cooling concept. FIGS. 2 through 8 are schematic views of exemplary embodiments of cooling systems of the disclosure with relative positioning of the various components. FIG. 9 includes a characteristic map of a characteristic-map control of the oil pump of FIG. 8. FIG. 10 is a table of typical pressure values in a charged air intake region of the internal combustion engine according to FIG. 2. FIG. 11 is a flow chart of a method of regulating pressure in a coolant system according to some of the embodiments disclosed herein.

(13) If shown directly contacting each other, or directly coupled, then the various components of the figures may be referred to as directly contacting or directly coupled, respectively, at least in one example. Similarly, elements shown contiguous or adjacent to one another may be contiguous or adjacent to each other, respectively, at least in one example. As an example, components laying in face-sharing contact with each other may be referred to as in face-sharing contact. As another example, elements positioned apart from each other with only a space there-between and no other components may be referred to as such, in at least one example. As yet another example, elements shown above/below one another, at opposite sides to one another, or to the left/right of one another may be referred to as such, relative to one another. Further, as shown in the figures, a topmost element or point of element may be referred to as a top of the component and a bottommost element or point of the element may be referred to as a bottom of the component, in at least one example. As used herein, top/bottom, upper/lower, above/below, may be relative to a vertical axis of the figures and used to describe positioning of elements of the figures relative to one another. As such, elements shown above other elements are positioned vertically above the other elements, in one example. As yet another example, shapes of the elements depicted within the figures may be referred to as having those shapes (e.g., such as being circular, straight, planar, curved, rounded, chamfered, angled, or the like). Further, elements shown intersecting one another may be referred to as intersecting elements or intersecting one another, in at least one example. Further still, an element shown within another element or shown outside of another element may be referred as such, in one example. In the different drawings, like parts are provided with the same reference numbers, as a result of which said parts are generally also described only once.

(14) The cooling system contains a predetermined amount of coolant 24. The coolant may be any type of coolant generally used. In exemplary embodiments, the coolant is a water/glycol mixture (typically 40% glycol). The cooling system may additionally comprise a liquid/gas heat exchanger 38, which is arranged on a front side of the motor vehicle in a known manner and is commonly also referred to as a cooler. Two coolant-temperature-dependent control elements 28, 30 of the cooling system, for example, thermostatic valves, represent fluidic connections between the various components of the cooling system depending on a temperature of the coolant 24. The cooling system may further include an equalizing tank 22, for receiving some of the coolant 24 in a coolant-temperature-dependent manner, and a coolant pump 20. The cooling system may additionally contain a plurality of connecting elements such as pipelines and tubes for producing fluidic connections.

(15) The cooling system may additionally include another liquid/gas heat exchanger 40 of a cab heater which is provided to release heat in a passenger compartment of the motor vehicle.

(16) The internal combustion engine 10 of the motor vehicle may be equipped with a turbocharger 32. A drive turbine 34 of the turbocharger 32 is driven in a known manner by an exhaust gas flow of the internal combustion engine 10. As a result, the drive turbine 34 moves a compressor 36 arranged on the same axle, which supplies air having an increased pressure by comparison with the external air pressure to an air intake region 12 of the internal combustion engine 10. Typical pressure values are indicated in the table of FIG. 10 according to an operating load point of the internal combustion engine 10 (rpm, top row) and a driving speed of the motor vehicle (km/h, first column).

(17) The internal combustion engine 10 contains a cylinder head having a cylinder-head cooling-jacket part 14 on the inlet side and a cylinder-head cooling-jacket part 16 on the exhaust side fluidically separated therefrom inside the internal combustion engine 10. The internal combustion engine 10 also has an engine block having an engine-block cooling jacket 18, which is fluidically separated from the cylinder-head cooling-jacket parts 14, 16 inside the internal combustion engine 10.

(18) The predetermined amount of coolant 24 is measured in such a way that, in the case of cold coolant 24, that is to say which is at the outside temperature, approximately half of the equalizing tank 22 is filled with coolant 24, and the space arranged thereabove is filled with air 26, the pressure of which corresponds to the normal atmospheric pressure plus the partial pressure of the coolant 24 (referred to in the following as normal atmospheric pressure for short).

(19) During a start-up phase of the internal combustion engine 10 of the motor vehicle with cold coolant 24, the two thermostatic valves 28, 30 are closed, and the coolant pump 20 conveys the coolant 24 along a first cooling circuit which contains the cylinder-head coolant part 16 on the exhaust side and the liquid/gas heat exchanger 40 of the cab heater.

(20) When the coolant temperature increases, the first thermostatic valve 28 firstly opens, and the coolant pump 20 conveys the coolant 24 in addition to the first cooling circuit through the engine-block cooling jacket 18, the cylinder-head coolant part 14 on the inlet side and a cooling-jacket part of an oil-filter/oil-cooler assembly 76 which is part of an oil lubrication circuit (not shown in greater detail in FIG. 1). The equalizing tank 22 is fluidically connected to the small cooling circuit on a lower face.

(21) When the coolant temperature increases further, the second thermostatic valve 30 also opens. The coolant pump 20 then conveys the coolant 24 along a large cooling circuit, that is to say through the cylinder-head coolant part 16 on the exhaust side, the engine-block cooling jacket 18, the cylinder-head coolant part 14 on the inlet side and the cooler 38 back to the coolant pump 20, the cooling-jacket part of the oil-filter/oil-cooler assembly 76 being flowed through in a secondary flow.

(22) In the case of a maximum coolant temperature, a maximum pressure in the equalizing tank 22 is approximately 1.4 bar (rel.).

(23) FIG. 2 is a schematic view of one possible embodiment of a cooling system according to the disclosure of an internal combustion engine 10 of a motor vehicle, which is constructed according to the split cooling concept. The cooling system according to the disclosure, the internal combustion engine 10 and the motor vehicle correspond to the embodiment according to the prior art, shown in FIG. 1, except for the differences which will be described in the following.

(24) In the cooling system according to the disclosure as shown in FIG. 2, a direct fluidic connection 42 is set up between a medium in the equalizing tank 22, which medium is formed by the air 26 under normal atmospheric pressure over the coolant 24, and a medium of another media path of the motor vehicle, the media path formed by the air intake region 12 which is charged by the turbocharger 32, and the medium formed by the charged air in the air intake region 12.

(25) In the case of a start-up and in particular a cold start of the internal combustion engine 10, a partial air-flow from the air intake region 12 of the internal combustion engine 10 is conducted into the air space of the equalizing tank 22, as a result of which the increased pressure of the air intake region 12 is transmitted to the cooling system and in particular to the coolant 24.

(26) FIG. 3 is a schematic view of an embodiment of the cooling system according to FIG. 2, comprising an alternative fluidic, activation-dependent connection 44 between the medium (air 26) in the equalizing tank 22 and the medium of another media path, which is formed by the air intake region 12 charged by the turbocharger 32.

(27) The activation-dependent, fluidic connection 44 between the air 26 in the equalizing tank 22 and the air intake region 12 of the internal combustion engine 10 contains an activatable non-return valve 46 which is permeable in the direction of the equalizing tank 22. The non-return valve 46 can be in the form of a spring-loaded non-return valve. The non-return valve 46 is activated, and thus the fluidic connection 44 is produced, in that the pressure of the charged air intake region 12 exceeds a threshold for the pressure which is predetermined by the force of the spring-loading of the non-return valve 46. If the pressure of the charged air intake region 12 falls below the threshold, then the non-return valve 46 closes, and the increased pressure in the coolant 24 of the cooling system is maintained. In some aspects, the threshold is 2 bar. In other aspects, the pressure may be maintained between about 1.5 to 2 bar or any fraction thereof, wherein about is 5%.

(28) FIG. 4 is a schematic view of an embodiment of the cooling system of FIG. 2, comprising another alternative fluidic, activation-dependent connection 48 between the medium (air 26) in the equalizing tank 22 and the medium of another media path, which is formed by the air intake region 12 charged by the turbocharger 32.

(29) The activation-dependent, fluidic connection 48 between the air 26 in the equalizing tank 22 and the air intake region 12 of the internal combustion engine 10 contains an electrically controllable valve 50, which can be in the form of a three-way valve. An activation and thus the production of the fluidic connection 48 takes place by a corresponding control of the valve 50 by, for example, an electronic control unit 52. The electronic control unit 52 can be provided for example to receive data from an engine control unit of the motor vehicle (not shown) which relate to a current operating state of the turbocharger 32. In this manner, the fluidic connection 48 between the air 26 in the equalizing tank 22 and the air intake region 12 of the internal combustion engine 10 can be produced by controlling the valve 50 for example in the case of a desired charging-air pressure in the air intake region 12.

(30) The control methods and routines disclosed herein such as those for control of the electrically controllable valves, may be stored as executable instructions in non-transitory memory and may be carried out by the control system including the electronic control unit 52 in combination with various sensors, actuators, and other engine hardware. Various actions, operations, and/or functions illustrated may be performed in the sequence illustrated, in parallel, or in some cases omitted. Likewise, the order of processing is not necessarily required to achieve the features and advantages of the example embodiments described herein, but is provided for ease of illustration and description. One or more of the illustrated actions, operations and/or functions may be repeatedly performed depending on the particular strategy being used. Further, the described actions, operations and/or functions may graphically represent code to be programmed into non-transitory memory of the computer readable storage medium in the control unit, where the described actions are carried out by executing the instructions in a system including the various engine and/or coolant system hardware components in combination with the control unit.

(31) FIG. 5 is a schematic view of an embodiment of the cooling system of FIG. 2, comprising an alternative direct, fluidic connection 54 between the medium (air 26) in the equalizing tank 22 and the medium of another media path, which is formed by the air intake region 12 charged by the turbocharger 32.

(32) The direct, fluidic connection 54 between the air 26 in the equalizing tank 22 and the air intake region 12 of the internal combustion engine 10 contains a throttle valve 56 for flow restriction, by which the amount of air which is conducted from the air intake region 12 into the equalizing tank 22 can be controlled.

(33) FIG. 6 is a schematic view of an embodiment of the cooling system of FIG. 2, comprising another alternative, direct, fluidic connection 58 between the medium (air 26) in the equalizing tank 22 and the medium of another media path, which is formed by the air intake region 12 charged by the turbocharger 32.

(34) The direct, fluidic connection 58 between the air 26 in the equalizing tank 22 and the air intake region 12 of the internal combustion engine 10 contains a pressure-control valve 60 to limit the pressure in the equalizing tank 22. The control pressure of the pressure-control valve 60 is selected in such a way that a pressure-relief valve (not shown) which is conventionally set up on an upper face of the equalizing tank 22 does not respond.

(35) FIG. 7 is a schematic view of an embodiment of the cooling system of FIG. 2, comprising a force-transmitting connection 62 between the medium (air 26) in the equalizing tank 22 and the medium of another media path, which is formed by the air intake region 12 charged by the turbocharger 32.

(36) The force-transmitting connection 62 between the air 26 in the equalizing tank 22 and the air intake region 12 of the internal combustion engine 10 contains a pressure intensifier 64 for increasing pressure. Using the pressure intensifier 64, an increased pressure by comparison with the air intake region 12 of the internal combustion engine 10 is achieved in the equalizing tank 22. Pressure intensifiers are known in the prior art and therefore do not need to be described in greater detail here.

(37) Although the various embodiments of the fluidic or force-transmitting connection between the medium (air 26) in the equalizing tank 22 and the medium of another media path which is formed by the air intake region 12 charged by the turbocharger 32 are shown and described in isolation, said embodiments can also be combined with one another in an expedient manner. For example, it can be expedient to combine the electrically controllable valve 50 of the cooling system according to FIG. 4 with the activatable non-return valve 46 of the cooling system according to FIG. 3. Further combinations will expediently be put together by a person skilled in the art according to requirements.

(38) FIG. 8 is a schematic view of an embodiment of the cooling system of FIG. 2, comprising a force-transmitting connection 66 between the medium in the equalizing tank 22, which medium is formed by the air 26 under normal atmospheric pressure over the coolant 24, and a medium of another media circuit of the motor vehicle, the media circuit being formed by an oil lubrication circuit 72 of the motor vehicle, and the medium being formed by the lubricating oil 78 circulating in the oil lubrication circuit 72.

(39) The force-transmitting connection 66 between the air 26 in the equalizing tank 22 and the lubricating oil 78 of the oil lubrication circuit 72 contains a pressure-transmission element 70 having media separation. In an alternative embodiment, the pressure-transmission element can be replaced by a fluid separator having a movable dividing wall or having a membrane.

(40) The oil lubrication circuit 72 contains an oil pump 74 which can be controlled by a characteristic map for circulating the lubricating oil 78 (FIG. 9). During operation of the oil pump 74, an operating pressure of the lubricating oil 78 is present at an output of the oil-filter/oil-cooler assembly 76, which pressure is transmitted to one side of the pressure-transmission element 70 by a line filled with lubricating oil. On the other side of the pressure-transmission element 70 facing away from the lubricating oil side, a direct, fluidic connection 68 to the air 26 in the equalizing tank 22 is set up.

(41) FIG. 9 contains an example of a characteristic map 80 of a characteristic-map control of the oil pump 74. Using the characteristic-map control, the oil pump 74 is provided to build up, according to an operating parameter of the internal combustion engine 10, namely the current operating load point thereof, and a driving parameter of the motor vehicle 10, namely the driving speed thereof, one of two predetermined operating pressure values p1, p2 for the lubricating oil at the output of the oil-filter/oil-cooler assembly 76.

(42) FIG. 11 is a flow chart of a method 1100 for regulating pressure in a coolant system of an internal combustion engine of a motor vehicle. Instructions for carrying out method 1100 and the rest of the methods included herein may be executed by a control unit based on instructions stored on a memory of the control unit and in conjunction with signals received from sensors of the engine system, such as the intake pressure sensor positioned at an intake line or at the intake manifold or a temperature sensor in the coolant line. The control unit may employ engine actuators of the engine system to adjust engine operation, according to the methods described below.

(43) When starting an engine with cold coolant, such as during a cold start, the pressure in the cooling system substantially corresponds to the normal atmospheric pressure. At 1110, method 1100 determines whether or not the engine is being cold started. In one example, method 1100 may determine the state of engine operating parameters to determine if the engine is being cold started. For example, if engine coolant temperature, as measured by the temperature sensor in the coolant line, is below a threshold temperature, it may be determined that the engine is experiencing a cold start. In the event that it is determined that the engine is not experiencing a cold start, the method proceeds to 1120 at which point current operating parameters are maintained. As used herein, maintaining current operating parameters may include maintaining a throttle valve (e.g. valve 56) or electronic control valve (e.g. valve 50) closed. However, in other examples, maintaining current operating parameters may include supplying pressure to the equalizing tank regardless of operating conditions.

(44) If it is determined at 1110 that the engine is experiencing a cold start, the method proceeds to 1130 and the pressure of the medium is increased. In exemplary aspects, the medium is formed by the air 26 under normal atmospheric pressure over the coolant 24. The pressure of the medium may be increased in a variety of ways including direct fluidic connection, one or more activation dependent fluidic connections, and/or one or more force-transmitting connections. Such methods may be used alone or in any combination. In some aspects, the pressure of the medium may be continuously maintained. For example, in some aspects, as shown in FIG. 2, the medium in the equalizing tank 22 is set up in direct fluidic connection with medium of another media path such as the media path formed by the air intake region 12 which is charged by the turbocharger 32. Thus, the increased pressure of the air intake region 12 is transmitted to the cooling system. In some aspects, when the threshold pressure is reached, the equalizing tank 22 may maintain the pressure by releasing excess pressure through a release valve. In additional aspects, increasing the pressure of the medium may include the use of a non-return valve such as non-return valve 46 as shown in the fluidic connection 44 of FIG. 3. When the pressure of the charged air intake region 12 exceeds a threshold for the pressure as determined by the force of the non-return valve, the valve opens, increasing the pressure of the medium. In further aspects, as in step 1140, the connection between the equalizing tank 22 and the air intake region 12 may be regulated by a throttle valve as in FIG. 5. In other aspects, alone or in combination with direct connection, additional activation dependent fluidic connections and one or more force-transmitting connections, an electronic control valve 1150 such as the pressure-control valve shown in FIG. 6 may be used to regulate the fluidic connection 58 between the medium in the equalizing tank 22 and the medium of another media path. In yet another aspect, such as that shown at step 1160, the pressure of the medium may be increased via a force-transmitting connection 62. The force-transmitting connection may include pressure intensifier as shown in FIG. 7. In some aspects, as shown at step 1170, a second force-transmitting connection 66, between the oil lubrication circuit 72 and a pressure-transmission element 70, may be used alone or in combination with other mechanisms to increase the pressure of the medium. In exemplary embodiments, the pressure-transmission element may have media separation. In further exemplary embodiments, the pressure-transmission element can be replaced by a fluid separator having a movable dividing wall or a membrane. Once the pressure reaches the appropriate threshold, the method 1100 ends.

(45) In examples where a controllable valve is included in the fluidic connection, e.g. as in FIGS. 4 and 5, the valve may be opened when intake pressure is higher than a threshold, for example higher than atmospheric pressure, and may be closed when intake pressure is lower than that threshold. In this way, air may be provided to the equalizing tank when air is higher than atmospheric pressure and may be prevented from back flowing into the intake manifold under low manifold pressure conditions.

(46) Although the embodiments of the cooling system described herein show at least one direct or at least one activation-dependent, fluidic connection, or at least one force-transmitting connection between a medium in the equalizing tank and in each case one other media path or media circuit of the motor vehicle, it is within the scope of the disclosure that such connections are set up to more than one other media path or media circuit of the motor vehicle, for example to the air intake region of the internal combustion engine and the oil lubrication circuit of the motor vehicle.

(47) The following claims particularly point out certain combinations and sub-combinations regarded as novel and non-obvious. These claims may refer to an element or a first element or the equivalent thereof. Such claims should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and sub-combinations of the disclosed features, functions, elements, and/or properties may be claimed through amendment of the present claims or through presentation of new claims in this or a related application. Such claims, whether broader, narrower, equal, or different in scope to the original claims, also are regarded as included within the subject matter of the present disclosure.

LIST OF REFERENCE SIGNS

(48) 10 internal combustion engine 12 air intake region 14 cylinder-head cooling-jacket part on the inlet side 16 cylinder-head cooling-jacket part on the exhaust side 18 engine-block cooling jacket 20 coolant pump 22 equalizing tank 24 coolant 26 air 28 control element 30 control element 32 turbocharger 34 drive turbine 36 compressor 38 liquid/gas heat exchanger 40 liquid/gas heat exchanger (heater) 42 fluidic connection 44 fluidic connection 46 activatable non-return valve 48 fluidic connection 50 electrically controllable valve 52 electronic control unit 54 fluidic connection

LIST OF REFERENCE SIGNS (CONT.)

(49) 56 throttle valve 58 fluidic connection 60 pressure-control valve 62 force-transmitting connection 64 pressure intensifier 66 force-transmitting connection 68 fluidic connection 70 pressure-transmission element 72 oil lubrication circuit 74 oil pump 76 oil-filter/oil-cooler assembly 78 lubricating oil 80 characteristic map p1 pressure value p2 pressure value