DEVICE FOR RETURNING OIL SEPARATED FROM BLOW-BY GASES AND ACCUMULATED IN AN ACCUMULATION CHAMBER

Abstract

The invention relates to a device for returning oil separated from blow-by gases and accumulated in an accumulation chamber (5) into the crankcase (2) of an internal combustion engine with a pump (9), wherein the pump (9) is located on a component (8) of the internal combustion engine, which component periodically changes the distance to the pump (9), and that the pump (9) can be driven by magnetic forces acting between the component (8) and the pump (9).

Description

The invention relates to a device for returning oil separated from blow-by gases and accumulated in an accumulation chamber into the crankcase of an internal combustion engine with a pump.

A generic device is known for example from DE 41 01 203 A1. In this device, an auxiliary pump is used for returning the separated oil. The auxiliary pump can for example be a vacuum pump for generating low pressure in a vehicle brake servo unit, which vacuum pump is driven by the internal combustion engine. It is a disadvantage of this embodiment that it necessitates a complex connection of the auxiliary pump to the device, in particular when the device is not located near the brake servo unit.

A further device is known from DE 20 2004 004 802 U1, in which device the pump is driven by the vibrational energy generated during operation of the internal combustion engine. The generated vibrational energy is conditional on the motion of the piston. However, experience has shown that the thus generated vibrational energy is not sufficient in internal combustion engines comprising more than five cylinders and thereby involving an enhanced running smoothness.

It is an object of the invention to improve a generic device in such a way that the return of the oil is rendered possible for internal combustion engines comprising six and more cylinders as well, wherein the constructional configuration shall be designed to be cost-effective and as simple as possible.

According to the invention, the object is solved by a device comprising the features of claim 1. Preferred embodiments can be learned from the sub claims.

According to claim 1, it is proposed that the pump is located on a component of the internal combustion engine, which component periodically changes the distance to the pump, and that the pump can be driven by magnetic forces acting between the component and the pump. The device proposed according to the invention thus provides the advantage that an already present component of the internal combustion engine is used for driving the pump, and that the proposed drive by means of magnetic forces requires no additional components for transmitting the force.

The magnetic forces can be easily generated by the pump or the component being magnet-equipped and by the respective other component being designed to be magnetic. The term “magnetic” here means that the component is attracted or repelled by the respective other component. In particular all ferromagnetic materials or even plastic materials containing ferromagnetic particles lend themselves as magnetic materials. Preferably permanent magnets lend themselves as magnets to be used, which permanent magnets do not require any connection to external components so that the whole device can be reliably operated in permanent operation even in a hermetically sealed system.

A further preferred embodiment of the invention is that the pump comprises a vulcanised, bonded or insert-moulded permanent magnet, or that the same is formed from a plastic material comprising magnetic particles and/or from an elastomer.

Thereby, a very easy way of magnet equipping is proposed, which can already be carried out during the manufacturing process of the pump or of the magnet-equipped part of the pump. Furthermore, the magnet is thus located on the pump in a loss-proof manner so that the functionality is guaranteed even during permanent operation after a high number of operating hours. Using an elastomer lends itself inasmuch as the magnetic particles can already be introduced during the vulcanisation process and can be magnetised as needed.

Furthermore, the pump or the component can be formed from an elastomer and/or from a plastic material, which elastomer comprises the magnetic particles in a limited portion only. The limited portion then expediently is the portion having the smallest distance during the periodic movement. As a result, optimal use is made of the generated magnetic force. The elastomer and/or the plastic material can then be injected in two steps by injecting the elastomer and/or the plastic material together with the magnetic particles in a first step, and by injecting the plastic material and/or the elastomer without magnetic particles in a second step. Both materials then unite by being vulcanised or fuse in the tool so that the finished part can subsequently be taken out of the machine.

It is further proposed that the pump comprises a diaphragm, and that the diaphragm can be induced to perform a stroke movement as a result of the changing distance of the component of the internal combustion engine. The proposed diaphragm provides a very easy but effective way of transforming the movement of the component moving with a periodically changing distance into a pressure pulsation effecting the return of the oil.

The diaphragm preferably has a spring elastic configuration, wherein the same can automatically be moved back to its initial position after performing the stroke movement. The diaphragm itself can for example be made of an elastomer, wherein the diaphragm then summons up the required reset force for moving back to the initial position by itself by means of its shaping. Alternatively, the diaphragm can also be mounted in a resilient manner and can consist of a dimensionally stable material, wherein the spring forces then pretension the diaphragm to the initial position.

One possibility of shaping is that the diaphragm comprises a circumferential bead. By the proposed bead, a particularly large stroke volume is provided at an equal dimension of the diaphragm so that, conversely, for a predetermined stroke volume, the diaphragm can be reduced in size accordingly.

It is further proposed that the pump is assigned to an intermediate chamber, and that the intermediate chamber can be connected to the accumulation chamber via a first non-return valve permeable in the inlet direction, and to the crankcase via a second non-return valve permeable in the outlet direction. By the proposed assignment of the pump to an intermediate chamber and by the connection to the accumulation chamber and to the crankcase via non-return valves, a device is provided, by which the movement of the periodically changing distance is transformed into a continuous sequence of alternating oil intake phases from the accumulation chamber and oil outlet phases into the crankcase.

A constructively easy way of transforming the periodic excitation by the component of the internal combustion engine is that the pump, at a small distance to the component, generates low pressure in the intermediate chamber and thereby intakes oil from the accumulation chamber by means of the first non-return valve into the intermediate chamber, and, at a large distance, pumps the oil from the intermediate chamber into the crankcase by means of the second non-return valve. The low pressure required for the pumping process is thus generated in the intermediate chamber by generating a magnetic attractive force by the component being moved by so that even in the event of the pump not functioning, as for example at a decreasing magnetic force, a distance is present between the pump and the component so that the component of the internal combustion engine does not touch at the pump and the perfect movement of the component cannot further be disturbed.

For example the cam shaft, the gas exchange valves or parts of the lever mechanism acting upon the gas exchange valves, as for example cam followers, rocker arms, roller-type cam followers, lend themselves as components moving with a periodically changing distance. These do not only provide the advantage of already performing a periodic movement due to their function, but also of being located geometrically near the place where the oil separated from the blow-by gases is returned in the valve body.

In particular in view of the functional reliability at a high number of operating hours it is proposed that the pump can be driven by the component in a non-contact manner. This provides the advantage that no abrasion occurs, and that the parts cannot lock or disturb each other's movement by touching at each other or by clamping.

In the following, the invention is described in more detail on the basis of preferred embodiments, wherein the figures show in detail:

FIG. 1: Device with a pump driven via a cam shaft

FIG. 2 a: Device according to FIG. 1 in the position “intaking oil from the accumulation chamber”

FIG. 2 b: Device according to FIG. 1 in the position “discharging oil into the crankcase”

FIG. 3: Device with a pump driven via a lever acting upon a gas exchange valve

FIG. 1 shows a device 1 for returning oil separated from blow-by gases and accumulated in an accumulation chamber 5 into the crankcase 2 of an internal combustion engine (not shown) with a pump 9. Herein, there is always talk of accumulated and separated oil, but it is in fact a matter of a mixture of oil with parts of unburnt fuel and water. The operating mode of the device in its basic principle, except the newly designed drive of the pump 9, corresponds to DE 20 2004 004 802 U1 of the same applicant, which document thus explicitly is to be added to the disclosure of the present application. The blow-by gases are introduced via an intake line 3 and first are directed through an oil separator 4. The separated oil is accumulated in an accumulation chamber 5 comprising a depression, on which a non-return valve 7a spring-loaded in the closing direction is located. When the spring force loading the non-return valve 7a is exceeded, the non-return valve 7a opens and allows the oil to discharge into an intermediate chamber 6, from which the same again can be directed further on into a crankcase 2 via a non-return valve 7b spring-loaded in the closing direction. The pressure in the intermediate chamber 6 can be varied via a pump 9 designed as a diaphragm, wherein the diaphragm 9 can be set into a stroke movement by a component, here a cam shaft 8. The cam shaft 8, during its rotation, performs a movement periodically changing the distance, by which movement the stroke movement of the diaphragm is effected. For a better understanding of the invention, FIGS. 2a and 2b show two different positions of the pump 9 driven by the cam shaft 8. In FIG. 2a, the cam of the cam shaft 8 is located directly in front of the pump 9 designed as a diaphragm at a distance D1. The diaphragm 9 is equipped with a magnet 11 so that the same is attracted in the arrow direction by the ferromagnetic cam of the cam shaft 8. As a result of the stroke of the diaphragm 9 low pressure symbolized by the symbols is generated in the intermediate chamber 6 causing the non-return valve 7a to open and allowing a transportation of the oil from the accumulation chamber 5 to the intermediate chamber 6. In order to facilitate the stroke movement and to increase the stroke volume, respectively, at an equal diaphragm surface, the diaphragm 9 is provided with an elastic circumferential bead 12. The diaphragm 9 itself can be formed for example from an elastomer, into which a magnet 11 has been vulcanised or inserted by insert-moulding. Alternatively, the elastomer itself can comprise magnetic particles as well, in particular in the area being located directly opposite the cam of the cam shaft 8. The magnet 11 is thereby further protected against external influences like dirt, temperature or mechanical stress. In the position shown in FIG. 2b, the cam shaft 8 is rotated by 90 degrees in the clockwise direction in relation to the position shown in FIG. 2a, whereby the distance between the cam shaft 8 and the diaphragm 9 is increased up to the distance D2. Due to the increased distance D2 the magnetic force is lower so that the diaphragm 9 has performed a reset movement in the arrow direction. In order that the reset movement is reliably performed, and that the diaphragm 9 does not rest in the position shown in FIG. 2a, the diaphragm 9 is spring-preloaded in the reset direction by the bead 12 and/or by the choice of the material so that the same automatically moves back from the position shown in FIG. 2a to the position shown in FIG. 2b. Alternatively or additionally, the diaphragm 9 can however be spring-preloaded with spring elements as well for supporting the reset movement. By the retraction movement of the diaphragm 9, the pressure in the intermediate chamber again increases so that the non-return valve 7b then opens and the oil is directly or indirectly directed further on into the crankcase 2.

FIG. 3 shows an alternative embodiment of the invention, in which the pump 9 is driven by a rocker arm 14. The rocker arm 14 with one end rests against a rotating cam shaft 8 and thereby performs a periodic swivelling motion so that the end of the rocker arm 14 resting against the valve 13 performs a movement with a periodically changing distance in front of the diaphragm 9. Apart from that, the transportation of the oil from the accumulation chamber 5 into the crankcase 2 is effected identically with the process described in FIGS. 2a and 2b.

Basically, it should be noted that, when the pump 9 is standing still and the oil has been accumulated, the non-return valves 7a and 7b open due to gravity and the oil can discharge so that even in the event of a failure of the pump 9 the oil is returned. The pressure pulsation generated by the pump 9 in the intermediate chamber 6 causes the non-return valves 7a and 7b to alternately open and close so that the oil flow is returned independent of its volume. In the extreme case, when no oil is separated, the pump 9 consequently pumps air.

Claims

1. Device for returning oil separated from blow-by gases and accumulated in an accumulation chamber into the crankcase of an internal combustion engine with a pump, wherein the pump is located a small distance from a component of the internal combustion engine, which component periodically changes the distance to the pump, and that the pump is driven by magnetic forces acting between the component and the pump.

2. Device according to claim 1, wherein either the pump or the component is magnet-equipped, and that the respective other part is designed to be magnetic.

3. Device according to claim 1, further comprising a permanent magnet.

4. Device according to claim 3, wherein the permanent magnet is selected from the group consisting of vulcanised, bonded or insert-moulded.

5. Device according to claim 1, further comprising plastic material comprising magnetic particles.

6. Device according to claim 1, further comprising an elastomer comprising magnetic particles.

7. Device according to claim 1, wherein the pump is formed from an elastomer, and magnetic particles are located within the elastomer.

8. Device according to claim 1, wherein the pump is formed from a plastic material, and magnetic particles are located within the plastic material.

9. Device according to claim 1, wherein the component is formed from an elastomer, and magnetic particles are located within the elastomer.

10. Device according to claim 1, wherein the component is formed from a plastic material, and magnetic particles are located within the plastic material.

11. Device according to claim 1, wherein the pump comprises a diaphragm that can be induced to perform a stroke movement as a result of the changing distance of the component of the internal combustion engine.

12. Device according to claim 11, wherein the diaphragm has a spring configuration and can automatically be moved back to the initial position after performing the stroke movement.

13. Device according to claim 11, wherein the diaphragm comprises a circumferential bead.

14. Device according to claim 1, wherein the pump is assigned to an intermediate chamber, the intermediate chamber being connected to the accumulation chamber via a first non-return valve permeable in the inlet direction, and to the crankcase via a second non-return valve permeable in the outlet direction.

15. Device according to claim 14, wherein the pump, at a first distance to the component, generates low pressure in the intermediate chamber and thereby intakes oil from the accumulation chamber via the first non-return valve into the intermediate chamber, and, at a second distance, pumps the oil from the intermediate chamber into the crankcase via the second non-return valve, the second distance being greater than the first distance.

16. Device according to claim 1, wherein the component is selected from a group consisting of a cam shaft, one of the gas exchange valves or a part of the lever mechanism acting upon the gas exchange valve.

17. Device according to claim 1, wherein the pump can be driven by the component in a non-contact manner.

18. Device for returning oil separated from blow-by gases and accumulated in an accumulation chamber into the crankcase of an internal combustion engine with a pump, wherein the pump is located a first distance from a component of the internal combustion engine, which component periodically changes the distance to the pump to a second distance, and that the pump is driven by magnetic forces acting between the component and the pump.

19. Device according to claim 18, wherein the second distance is greater than the first distance.

20. Device for returning oil separated from blow-by gases and accumulated in an accumulation chamber into the crankcase of an internal combustion engine with a pump, wherein the pump comprises a diaphragm and the pump is located a first distance from a component of the internal combustion engine, which component periodically changes the distance to the pump to a second distance, the device further comprising a permanent magnet positioned such that the pump is driven by magnetic forces acting between the component and the pump.