Oil supply system of a motor vehicle with an internal combustion engine, motor vehicle and method for operating the same

Abstract

Oil supply system (14) of a motor vehicle with an internal combustion engine, comprising an oil reservoir (15) or an oil pan designed for storing oil, an oil pump (16) designed to extract oil from the oil reservoir (15) or the oil pan and deliver it towards an oil consumer (17), and an oil storage device (18) arranged downstream of the oil pump (16) and upstream of the oil consumer (17) in the direction of oil delivery, wherein the oil storage device (18) is designed to store a defined volume of oil without pressure in a first state when the internal combustion engine is stationary, and to pressurize the stored oil in a second state when the internal combustion engine is started and to supply at least a portion of the stored oil to the oil consumer (17).

Description

The invention relates to an oil supply system for a motor vehicle with an internal combustion engine according to the preamble of claim 1. Furthermore, the invention relates to a motor vehicle and a method for operating the motor vehicle. DE 196 04 865 A1 discloses an oil supply system for a motor vehicle for supplying oil to an actuator cylinder of a camshaft adjuster of an internal combustion engine of the motor vehicle. The oil supply system has an oil pan from which oil can be supplied to an oil consumer, namely a hydraulic cylinder, by means of an oil pump. Furthermore, the hydraulic cylinder can be supplied with oil from a further oil reservoir by means of another oil pump. US 9 677 435 B2 discloses an oil guide structure for an internal combustion engine. When the engine of a motor vehicle with an internal combustion engine is switched off, the oil pumps of the oil supply system are generally not driven. Oil consumers can only be supplied with oil once the engine is running and driving the respective oil pump. Since it typically takes several seconds for the oil pump to build up oil pressure and thus ensure an oil supply, there is a risk that hydraulic consumers will not receive sufficient oil during this time. This can lead to increased wear on the oil consumers. There is a need to supply oil consumers with a sufficient quantity of oil, especially when the combustion engine is started. The object of the invention is to provide a corresponding oil supply system for a motor vehicle with an internal combustion engine, a motor vehicle with such an oil supply system, and a method for operating such a motor vehicle. This object is achieved by an oil supply system for a motor vehicle with an internal combustion engine according to claim 1, a motor vehicle according to claim 9, and a method according to claim 10 or 11. The oil supply system according to the invention comprises an oil storage device arranged downstream of the oil pump and upstream of the oil consumer in the direction of oil delivery, which is configured to store a defined volume of oil without pressure in a first state when the internal combustion engine is stationary, and to pressurize the stored oil in a second state when the internal combustion engine is started and to provide at least a part of the stored oil to the oil consumer. With the oil supply system according to the invention, hydraulic consumers of a motor vehicle with an internal combustion engine can be supplied with a sufficient quantity of oil even when the internal combustion engine is being started. For this purpose, the oil supply system according to the invention has an oil storage device which, in a first state when the internal combustion engine is stationary, stores the defined volume of oil without pressure. In a second state, when the internal combustion engine is started, the device pressurizes the stored oil and makes at least part of it available to the oil consumer. Thus, the oil supply to each individual oil consumer can be ensured, particularly in the first few seconds of an internal combustion engine start, when the engine is not yet able to drive an oil pump to such an extent that it supplies a sufficient quantity of oil to each consumer. Preferably, a check valve is arranged downstream of the oil pump and upstream of the oil storage device in the direction of oil flow. This check valve is designed to prevent oil flow from the oil storage device towards the oil pump. This prevents the oil stored in the oil storage device from being forced towards the oil pump. According to a first embodiment of the invention, the oil storage device has a housing which, together with a piston arranged in the housing, limits an oil storage volume, wherein the piston carries a permanent magnet and is acted upon by a spring element arranged in the housing, and wherein the oil storage device further has a switchable electromagnet with a ferrite core which, in a first switching state, holds the piston against the spring force of the spring element in a position in which it does not pressurize the oil stored in the oil storage volume, and which, in a second switching state, releases the piston in order to pressurize the oil stored in the oil storage volume.According to a second, alternative embodiment of the invention, the oil storage device has a housing which, together with a piston arranged in the housing, limits an oil storage volume, wherein the piston carries a ferrite core and is acted upon by a spring element arranged in the housing, and wherein the oil storage device further has a switchable electromagnet with a magnetic core which, in a first switching state, holds the piston against the spring force of the spring element in a position in which it does not pressurize the oil stored in the oil storage volume, and which, in a second switching state, releases the piston in order to pressurize the oil stored in the oil storage volume.Preferably, in the first switching state, the electromagnet attracts the permanent magnet or the ferrite core received by the piston, while in the second switching state, the electromagnet repels the permanent magnet or the ferrite core received by the piston and supports the spring element when oil pressure builds up. With both embodiments, it is possible in a particularly simple constructive way to store the oil volume without pressure in the first state of the oil storage device and to pressurize the stored oil in the second state of the same and to make at least part of the oil available to the respective oil consumer. Preferred embodiments of the invention are set forth in the dependent claims and the following description. Exemplary embodiments of the invention are explained in more detail with reference to the drawings, without being limited thereto. Figure 1 shows an oil supply system according to the invention for a motor vehicle with an internal combustion engine, Figure 2 shows a detail of Figure 1, Figure 3 shows an alternative to the detail of Figure 2, and Figure 4 shows a motor vehicle according to the invention with an oil supply system according to the invention. Fig. 4 shows a motor vehicle 10 with an internal combustion engine 11, which is designed as a hybrid vehicle, i.e., in addition to the internal combustion engine 11, it has electric machines 12, 13 assigned to the axles of the motor vehicle 10 as further drive units. Although Fig. 4 shows a motor vehicle 10 designed as a hybrid vehicle, which has the internal combustion engine 11 and the electric machines 12 and 13 as drive units, the invention can also be used in a purely internal combustion engine-powered motor vehicle. The motor vehicle 10 has an oil supply system 14, which is shown in greater detail in Fig. 1. The oil supply system 14 has an oil reservoir 15 or an oil pan, the oil reservoir 15 or the oil pan being designed to store oil. Furthermore, the oil supply system 14 includes an oil pump 16. The oil pump 16 is designed to draw oil from the oil reservoir 15 and deliver it towards an oil consumer 17. In Fig. 1, the oil consumer 17 is an exhaust gas turbocharger, to which the oil is supplied via the oil pump 16 for lubrication and / or cooling. From the oil consumer 17, the oil flows back towards the oil reservoir 15 or the oil pan. When the internal combustion engine 11 of the motor vehicle is stationary, it cannot drive the oil pump 16. When the internal combustion engine 11 is started, it may take a few seconds before it can drive the oil pump 16 sufficiently to supply the oil consumers 17 with oil. In order to supply oil consumers 17 with sufficient oil, especially when the combustion engine 11 is started while stationary, the oil supply system 14 according to the invention has an oil storage device 18 which is arranged downstream of the oil pump 16 and upstream of the oil consumer 17 in the direction of oil delivery and is integrated into the oil supply system 14. The oil storage device 18 is configured to store a defined volume of oil without pressure in a first state when the internal combustion engine 11 is stationary. Furthermore, the oil storage device 18 is configured, in a second state when the internal combustion engine is requested to start, to pressurize the oil stored in the oil storage device 18 and to supply at least a portion of the stored and pressurized oil to at least one oil consumer 17. Thus, even if the internal combustion engine 11 is not yet able to drive the oil pump 16 sufficiently when it is started, at least one oil consumer 17 can be adequately supplied with oil. Figs. 2 and 3 show exemplary embodiments of the oil storage device 18, from which it can be seen that, viewed in the direction of oil delivery, a check valve 19 is provided downstream of the oil pump 16 and upstream of the oil storage device 18, which is designed to prevent an oil flow from the oil storage device 18 towards the oil pump 16. The oil storage device 18 has a housing 20 which defines a preferably cylindrical oil storage volume 21, together with a piston 22 arranged in the housing 20. The piston 22 is movable within the housing 20. In Fig. 2, the piston 22 carries a permanent magnet 23, of which its south pole S and north pole N are shown as poles. A spring element 24 is also arranged in the housing 20, which is supported on one side by the housing 20 and on the other side by the piston 22. A spring force of the spring element 24 tends to push the piston 23 upwards in Fig. 2, thereby reducing the oil storage volume 21 available for storing oil. The oil storage device 18 further comprises a switchable electromagnet 25 with a ferrite core 26. In a first switching state of the electromagnet 25, the electromagnet 25, namely its ferrite core 26, holds the piston 22 against the spring force of the spring element 24 in a first position, which is shown in Fig. 2. In this first position of Fig. 2, the piston 23 is in a position maximally recessed into the housing 20, or maximally downwards, in which the available oil storage volume 21 is maximized. In this first position, the piston 23, and thus the oil storage device 18, does not pressurize the oil stored therein. In the state of Fig. 2, namely in the first switching state of the electromagnet 25, it is not electrically energized; the ferrite core 26 forms a north pole adjacent to the piston 22, or adjacent to the permanent magnet 23 held by the piston 22. When the electromagnet 25 is electrically energized and switched to its second switching state, the ferrite core 26 forms a south pole adjacent to the piston 22 or adjacent to the permanent magnet 23 held by the piston 22. In this state, the ferrite core 26, and thus the electromagnet 25, pushes the piston 22 upwards in addition to the spring element 24, thereby reducing the oil reservoir volume 21, pressurizing the oil contained therein, and ultimately supplying it to the oil consumer 17. When the electromagnet 25 in Fig. 2 is not electrically energized, the ferrite core 26 forms a north pole adjacent to the piston 22 or adjacent to the permanent magnet held by the piston 22. This north pole then holds the piston 22 in its lower position, counteracting the spring force of the spring element 24. In the second embodiment of the oil storage device 18 according to Fig. 3, the piston 22 carries a ferrite core 27 and the switchable electromagnet 25 has a magnetic core 28. If the switchable electromagnet 25 is not electrically energized in the embodiment of Fig. 3, then the magnetic core 28 has a magnetic attraction for the ferrite core 27 and can hold the piston 22 in the position shown in Fig. 3 against the spring force of the spring element 24 by attracting its ferrite core 27. If, on the other hand, the switchable electromagnet 25 is electrically energized in the embodiment of Fig. 3, then the magnetic core 28 has no magnetic attraction for the ferrite core 27 and the spring element 24 can push the piston 22 upwards. In both embodiments, the piston 22 and the spring element 24 are arranged within an interior space bounded by the housing 20, the switchable electromagnet 25 is positioned outside this interior space, but is arranged in a corresponding recess 29 of the housing, wherein the respective switchable electromagnet 25 is received in the recess outside the interior space and the spring element 24 is arranged adjacent to the recess 29 inside the interior space. The indentation 29 defines a stop for the piston 22 of the oil storage device 18 in its first state. Opposite the indentation 29, a further stop 30 is formed on the housing 30, which limits the upward movement of the piston 22. When the internal combustion engine 10 is switched off, the switchable electromagnet 25 is not energized and holds the piston 22 in the position shown in Fig. 2 and Fig. 3, against the spring force of the spring element 24. In this state, oil can then be stored without pressure in the oil reservoir 21. When the internal combustion engine 10 is started, the switchable electromagnet 25 is energized and switched to its second state, releasing the piston 22 so that the spring element 24, preferably assisted by the electromagnet 25, pushes the piston 22 upwards, thereby compressing the oil within the reservoir 21 and conveying at least some of it towards the hydraulic consumer 17. When the internal combustion engine 10 is switched off, a defined volume of oil is stored without pressure in the oil storage device 18 in the first state, with the electromagnet 25 not energized. Then, when the internal combustion engine 10 is started, the oil stored in the oil storage device 18 is pressurized in a second state and at least partially supplied to the oil consumer 17, for which purpose the switchable electromagnet 25 is energized. Following the pressurization of the oil stored in the oil storage device 18 and its supply to the oil consumer 17, the oil storage device 18 can then, when the oil pump 16 delivers oil, be returned to its first state and store oil. It will then only be returned to the second state again upon the next start of the internal combustion engine 10. In this case, it will be kept in the first state while the internal combustion engine 10 is running. Alternatively, it is also possible that, following the supply of oil to the oil consumer 17 from the oil storage device 18, the latter is moved between the first and second states while the combustion engine 11 is running until the combustion engine 11 is stopped, in order to support the oil supply to the oil consumer 17 even while the combustion engine 11 is running. In this case, the oil storage device 18 would only be held in the state shown in Figs. 2 and 3 once the combustion engine 11 is stopped. With the oil supply system 14 according to the invention, oil can be stored without pressure with minimal effort and, when required, pressurized in a pulsed or instantaneous manner and supplied to an oil consumer 17. The oil supply system 14 according to the invention can include several oil storage devices 18. Each oil storage device 18 is preferably arranged in the immediate vicinity of each oil consumer 17, which is to be supplied with oil from the respective oil storage device 18. QUOTES INCLUDED IN THE DESCRIPTION This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature DE 196 04 865 A1

[0002] US 9 677 435 B2

[0003]

Claims

Oil supply system (14) of a motor vehicle (10) with an internal combustion engine (11), with an oil reservoir (15) or an oil pan designed for storing oil, and with an oil pump (16) designed to extract oil from the oil reservoir (15) or the oil pan and deliver it towards an oil consumer (17), characterized by an oil storage device (18) arranged downstream of the oil pump (16) and upstream of the oil consumer (17) in the direction of oil delivery, wherein the oil storage device (18) is designed to store a defined volume of oil without pressure in a first state when the internal combustion engine (11) is stationary, and to pressurize the stored oil in a second state when the internal combustion engine (11) is started and to supply at least a portion of the stored oil to the oil consumer (17). Oil supply system (14) according to claim 1, characterized in that a check valve (19) is arranged downstream of the oil pump (16) and upstream of the oil storage device (18) in the direction of oil delivery, which is configured to prevent an oil flow from the oil storage device (18) towards the oil pump (16). Oil supply system (14) according to claim 1 or 2, characterized in that the oil storage device (18) has a housing (20) which, together with a piston (22) arranged in the housing (20), limits an oil storage volume (21), wherein the piston (22) carries a permanent magnet (23) and is acted upon by a spring element (24) arranged in the housing (18), the oil storage device (18) has a switchable electromagnet (25) with a ferrite core (26) which, in a first switching state, holds the piston (22) against the spring force of the spring element (24) in a position in which it does not pressurize the oil stored in the oil storage volume (21), and which, in a second switching state, releases the piston (22) to pressurize the oil stored in the oil storage volume (21) and to supply it to the oil consumer (17). Oil supply system (14) according to claim 3, characterized in that the electromagnet (25) attracts the permanent magnet received by the piston (22) in the first switching state, the electromagnet (25) repels the permanent magnet received by the piston (22) in the second switching state and supports the spring element (24) when pressure builds up of the oil. Oil supply system (14) according to claim 1 or 2, characterized in that the oil storage device (18) has a housing (20) which, together with a piston (22) arranged in the housing (20), defines an oil storage volume (21), wherein the piston (22) carries a ferrite core (27) and is acted upon by a spring element (24) arranged in the housing (20), the oil storage device (18) has a switchable electromagnet (25) with a magnetic core (28) which, in a first switching state, holds the piston (22) against the spring force of the spring element (24) in a position in which it does not pressurize the oil stored in the oil storage volume (21), and which, in a second switching state, releases the piston (22) in order to pressurize the oil stored in the oil storage volume (21) and to supply it to the oil consumer (17). Oil supply system (14) according to claim 5, characterized in that in the first switching state the electromagnet (25) attracts the permanent magnet ferrite core received by the piston (22), in the second switching state the electromagnet (25) repels the ferrite core received by the piston (22) and supports the spring element (24) when pressure builds up of the oil. Oil supply system (14) according to one of claims 3 to 6, characterized in that the piston (22) and the spring element (24) are arranged within an interior space defined by the housing (20), wherein the spring element (24) is supported on the housing (20) and on the clamp (22). Oil supply system (14) according to claim 7, characterized in that the electromagnet (25) is arranged outside the interior space defined by the housing (20). Motor vehicle with an oil supply system (14) according to one of claims 1 to 8, wherein the same is a hybrid vehicle or a purely internal combustion engine-powered motor vehicle. Method for operating a motor vehicle with an oil supply system (14) according to claim 9, wherein, when the internal combustion engine (11) is switched off, a defined volume of oil is stored without pressure in the oil storage device (18) in the first state of the oil storage device (18), then, when the internal combustion engine (11) is started, in the second state of the oil storage device (18) the oil stored in the oil storage device (18) is pressurized and at least partially supplied to the oil consumer (17), wherein subsequently, when the oil pump (16) delivers oil, the oil storage device (18) is transferred to the first state and is held in the first state until the next engine start. Method for operating a motor vehicle with an oil supply system (14) according to claim 9, wherein, when the internal combustion engine (11) is switched off, a defined volume of oil is stored without pressure in the oil storage device (18) in the first state of the oil storage device (18), then, when the internal combustion engine (11) is started, in the second state of the oil storage device (18) the oil stored in the oil storage device (18) is pressurized and at least partially supplied to the oil consumer (17), wherein the oil storage device (18) is subsequently switched between the first state and the second state even when the internal combustion engine (11) is running until the internal combustion engine (11) is switched off.

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