CN115263494A

CN115263494A - Ventilation equipment

Info

Publication number: CN115263494A
Application number: CN202210369882.3A
Authority: CN
Inventors: 蒂诺·伯特歇尔; 马克·德雷森; 阿图尔·克瑙斯; 曼弗雷德·布兰德
Original assignee: Bruss Sealing Systems GmbH
Current assignee: Bruss Sealing Systems GmbH
Priority date: 2021-04-29
Filing date: 2022-04-08
Publication date: 2022-11-01
Also published as: DE102021111051A1; DE102021111051B4

Abstract

The invention relates to a ventilation device (10) for ventilating a crankcase of an internal combustion engine, comprising: an intake port (11) for entering blow-by gas (12) from a crankcase (13); an oil separator (20) having an outlet side with an exhaust port (15) and a first oil return device (16) for leading out the separated oil; a suction jet pump (30) having an inlet (31) for blow-by gas, an inlet (32) for fuel gas (33), and an outlet (34) for a mixture (35) of blow-by gas (12) and fuel gas (33). The suction jet pump is arranged in terms of flow between the intake opening (11) and the oil separator (20), and a mixture (35) of blow-by gas (12) and fuel gas (33) can be conveyed from the suction jet pump (30) to the inlet (21) of the oil separator (20), wherein a second oil return device (17) is arranged between the outlet (34) of the suction jet pump (30) and the inlet (21) of the oil separator (20).

Description

Ventilation device

Technical Field

The present invention relates to a ventilation device for ventilation of the crankcase of an internal combustion engine according to the preamble of claim 1.

Background

In the prior art, an apparatus for crankcase ventilation of an internal combustion engine is known, for example from DE 10 2015 219 203A1, which uses a suction jet pump in order to achieve an increase in oil separation efficiency and to ensure a lower crankcase pressure.

The available pressure of fuel gas, typically taken from the intake port of an internal combustion engine, and the amount of blow-by gas produced in the crankcase vary with the operating point of the internal combustion engine. This can negatively impact the separation effectiveness of the oil separator and the efficiency of the overall system. Furthermore, a continuous return flow of oil can be prevented at certain operating points of the internal combustion engine.

Disclosure of Invention

The object of the invention is to provide a ventilation device for the ventilation of the crankcase of an internal combustion engine, which achieves a high efficiency and ensures continuous oil return over a wide operating range.

The invention is achieved by the features of the independent claims. A ventilation device for ventilating a crankcase of an internal combustion engine is proposed, which ventilation device comprises: an intake port for intake of blow-by gas from the crankcase; an oil separator having an outlet side with an exhaust port and a first oil return device for leading out the separated oil; and a suction jet pump having an inlet for the blow-by gas, an inlet for the fuel gas, and an outlet for a mixture of the blow-by gas and the fuel gas. In terms of flow technology, a suction jet pump is arranged between the intake opening and the oil separator, and a mixture of blow-by gas and fuel gas can be conveyed from the suction jet pump to the inlet of the oil separator, wherein a second oil return device is arranged between the outlet of the suction jet pump and the inlet of the oil separator. In other words, the suction jet pump is disposed upstream of the oil separator.

In order to achieve an oil separation efficiency over a wide operating range, it can be advantageous in terms of flow technology to provide the suction jet pump upstream of the oil separator. The blow-by gas flows from the crankcase into the suction jet pump and is mixed with fuel gas or fuel air, which is introduced into the suction jet pump at a higher velocity than the blow-by gas. The resulting mixture of blow-by gas and fuel gas is applied to an oil separator, and oil is separated from the mixed gas stream.

In this case, the proposed second oil return device between the ejector pump and the oil separator (i.e. downstream of the ejector pump and upstream of the oil separator) is advantageous in terms of flow technology for the proposed arrangement of the ejector pump in the ventilation device. Thus, continuous operation of the ventilation device can be achieved over a wide operating range of the internal combustion engine, which can be achieved by adjusting the pressure ratio. The application of blow-by gas to the ejector pump is fundamentally disadvantageous compared to the application of oil-free gas, since, due to system constraints, a certain oil separation effect occurs in the ejector pump, which adversely affects the efficiency, in particular in the case of long operating times of the ejector pump. However, the proposed second oil return after the ejector pump can lead out oil or larger drops which are separated as a secondary effect of the ejector pump, so that an improved ventilation device as a whole can be realized.

According to a further development, it is provided that the second oil return device has a volume flow limiting valve which is set to limit the volume flow through the second oil return device. The restricted volume flow in the second oil return means refers to the flow direction of the volume flow from the ventilation device to the crankcase. The volume flow limiting valve limits the volume flow, i.e. the volume flow or the gas flow and/or the oil flow can substantially reach a limit or can be reduced. This is fundamentally different from a non-return valve, which prevents any volume flow in an undesired direction. The volume flow limiting valve can, for example, have a pressure loss which increases with the applied volume flow.

According to a further development, the volume flow limiting valve is a counter-pressure switching valve which is set to close the second oil return device when a threshold value of the pressure difference at the counter-pressure switching valve is exceeded.

The pressure difference threshold is exceeded if the pressure between the suction jet pump and the oil separator in the ventilation device is higher than the pressure at the end of the oil return or in the crankcase of the internal combustion engine by a corresponding factor. Thus, the counterpressure switching valve is closed when there is a higher volume flow caused by a correspondingly higher pressure difference above the pressure difference threshold value. Thus, the backpressure switching valve is a self-closing valve that closes when the pressure threshold is reached, thereby distinguishing it from a pressure switching valve that opens when the pressure threshold is reached.

By means of the counterpressure switching valve it can advantageously be ensured that: in unfavorable operating states, no excessive mixture of blow-by gas and fuel gas or fuel air is recirculated via the second oil return device to the intake of the ventilation device, and ventilation or oil separation becomes inefficient.

It is also proposed that the counter-pressure switching valve of the second oil return device has a throttle bypass. The throttle bypass prevents a large amount of oil from accumulating when the counter-pressure switching valve is closed, so that a minimum backflow via the second oil return means is possible at all times. The throttling of the bypass means that the closing effect of the counter-pressure switching valve is not affected and unnecessary circulation through the ventilation device can be avoided.

It is also proposed that the second oil return device has a check valve. At such a pressure ratio the non-return valve prevents a back flow of medium from the crankcase via the second oil return.

In an advantageous embodiment, the second oil return means preferably has a throttle. The throttle in the second oil return device achieves that the mixture of blow-by gas and fuel gas is guided mainly through the oil separator and that no undesired circulation takes place before the oil separator.

It is also proposed that the first oil return device has a throttle. In the proposed arrangement in which the suction jet pump is located upstream of the oil separator, the throttle in the first oil return device for returning the oil separated in the oil separator achieves an advantageous pressure ratio which facilitates the outflow of the mixture of blow-by gas and fuel gas, which is now largely free of oil, from the exhaust opening of the ventilation device.

According to a further development, it is provided that the ventilation device has a throttle valve and/or a pressure regulating valve downstream of the outlet opening of the oil separator. The ventilation device therefore preferably has a throttle valve and/or a pressure regulating valve at the outlet. This means that the discharge conditions are always present after the exhaust of the oil separator, in particular at the first oil return. Since the exhaust port of the oil separator is provided for connection to the intake system of an internal combustion engine without an intermediate suction jet pump, too low a pressure can exist for continuous discharge conditions.

Drawings

The invention is described below in terms of preferred embodiments with reference to the accompanying drawings. Therein is shown

Fig. 1 shows a ventilation device with a suction jet pump before an oil separator and a second oil return;

fig. 2 shows a ventilation device with a suction jet pump before the oil separator and with a counterpressure switching valve with a bypass in a second oil return;

FIG. 3 shows a breather with a suction jet pump before the oil separator and with a throttle valve and a check valve;

FIG. 4 shows a breather with a suction jet pump before the oil separator and with a throttle valve and a check valve in a first oil return;

FIG. 5 shows a ventilation device with a pressure regulating valve before the suction jet pump;

FIG. 6 shows a venting apparatus with a pressure regulating valve located before an oil separator;

FIG. 7 shows a ventilation device with a throttle valve at the exhaust port;

FIG. 8 shows a ventilation device with a pressure regulating valve at the exhaust port;

Detailed Description

Fig. 1 shows a schematic illustration of a ventilation device 10 for ventilating a crankcase 13 (see also fig. 5), which has an air inlet 11. The blowby gas 12 can enter the intake port 11 from the crankcase 13 to flow into the ventilation apparatus 10. The blow-by gas 12 is directed into a corresponding inlet 31 of the suction jet pump 30 of the ventilation device 10. The ejector pump 30 also has an inlet 32 for fuel gas 33, which can be compressed charge air, for example, from a pressure section of an intake tract of an internal combustion engine. The ejector pump 30 delivers the mixture 35 generated in the ejector pump 30 via the space 36 to the inlet 21 of the oil separator 20. The oil separated in the oil separator 20 is returned from the ventilation device 10 via the first oil return 16 into the crankcase 13 or oil sump. The remaining gas is discharged from the ventilation device 10 via the exhaust opening 15 and is usually fed to the underpressure section of the intake tract of the internal combustion engine.

A second oil return 17 is arranged in the space 36 between the ejector pump 30 and the oil separator 20, from which space 36 or a corresponding line section the oil can be returned into the crankcase 13, so that an accumulation of oil separated by the ejector pump 30 can be avoided.

Fig. 2 shows a schematic illustration of a further exemplary embodiment of the ventilation device 10, which, in contrast to the exemplary embodiment of fig. 1, has a volume limitation valve 40 in the second oil return 17, which is embodied as a counter-pressure switching valve 41 with a bypass 42. The counter-pressure switching valve 41 is opened in the rest position so that a larger discharge cross section of the second oil return 17 is obtained. If the suction jet pump 30 is activated or a higher pressure difference is created between the space 36 and the outlet of the second oil return 17, so that the volume flow of the mixture 35 from the outlet 34 to the second oil return 17 increases, the counter-pressure switching valve 41 is closed. Accordingly, when the counter-pressure switching valve 41 is closed due to an excessive pressure difference, the second oil return device 17 is ensured only by the bypass 42, so that the oil separated in the space 36 can be discharged. The bypass 42, due to the small cross section, permits only a limited volume flow or achieves a high pressure loss, so that the function of a throttle valve is achieved. Thus, even when the suction jet pump 30 is operated at high power, the volume flow of the mixture 35 through the second oil return 17 can be limited to avoid unnecessary circulation.

Fig. 3 shows a schematic illustration of the ventilation device 10 with a throttle 44 in the second oil return 17 in order to achieve a sufficiently high pressure at the inlet 21 of the oil separator 20 at each operating point and to avoid unnecessary circulation. The throttle 44 can be realized, for example, by a shutter in the oil return 17. Furthermore, a check valve 43 is provided in the oil return 17 in order to avoid an undesired return flow from the second oil return 17 into the space 36 in any case.

Fig. 4 shows a further embodiment of the ventilation device 10, wherein the second oil return 17 has a counter-pressure switching valve 41 with a bypass 42. In the second oil return device 17, the check valve 43 is arranged downstream of the bypass 42 in the discharge direction. The bypass 42 also acts as a throttle to ensure that there is a sufficient pressure drop at the second oil return 17 for operation of the oil separator 20 whenever. In the embodiment of fig. 4, a throttle valve 44 and a check valve 43 are provided in the first oil return device 16. The throttle 44 and the non-return valve 43 in the first oil return 16 can also be used individually or together in the previously described embodiments of fig. 1, 2 and 3.

Fig. 5 shows an embodiment of the ventilation device 10 with a pressure regulating valve 14 after the air inlet 11. The pressure regulating valve 14 is used to regulate the negative pressure in the adjacent crankcase 13 from which the blowby gas 1 flows out, or to prevent the pressure in the crankcase 13 from being too low. In this advantageous embodiment, a third oil return device 18 with a check valve 43 is arranged in the space 37 adjoining the pressure regulating valve 14 in terms of flow technology. The third oil return 18 can be used to return any oil separation through the pressure regulating valve 14 before the inlet 31 of the ejector pump 30, so that the ejector pump 30 is not loaded with larger oil droplets. In an alternative embodiment, the third oil return 18 can also be omitted.

In another embodiment, see fig. 6, the pressure regulating valve 14 and the third oil return 18 arranged in the adjoining space 37 can also be arranged between the suction jet pump 30 and the oil separator 20.

In the embodiment of fig. 7, the throttle valve 45 is arranged after the intake port 15 or at the intake port 15, whereby the discharge conditions at the

oil return devices

16, 17, 18 can be ensured for each operating point. This is particularly true when the exhaust port 15 adjoins a negative pressure section of the intake duct with a very low pressure.

Fig. 8 shows an embodiment of the ventilation device 10 with a pressure regulating valve 46 at the exhaust opening 15, so that the drainage condition of the

oil return

16, 17 can be set at each operating point of the internal combustion engine. In particular in gasoline engines, very high vacuum can be generated after the throttle in partial load operation, so that it can be expedient to protect upstream components from excessive vacuum.

Claims

1. A ventilation device (10) for the ventilation of the crankcase of an internal combustion engine, comprising

-an inlet port (11) for entering blow-by gas (12) from a crankcase (13),

-an oil separator (20) having on an outlet side a gas outlet (15) and a first oil return (16) for leading out separated oil,

-a suction jet pump (30) having an inlet (31) for the blow-by gas (12), an inlet (32) for a fuel gas (33) and an outlet (34) for a mixture (35) of the blow-by gas (12) and the fuel gas (33), wherein

-in terms of flow technology, the ejector pump (30) is arranged between the air inlet (11) and the oil separator (20), and a mixture (35) of the blow-by gas (12) and the fuel gas (33) can be conveyed from the ejector pump (30) to the inlet (21) of the oil separator (20),

it is characterized in that the preparation method is characterized in that,

-a second oil return (17) is arranged between the outlet (34) of the suction jet pump (30) and the inlet (21) of the oil separator (20).

2. A ventilation device (10) according to claim 1, characterized in that the second oil return means (17) has a volume flow limiting valve (40) which is arranged to limit the volume flow through the second oil return means (17).

3. The ventilation apparatus (10) according to claim 2, characterized in that the volume flow restriction valve (40) is a counter-pressure switching valve (41) which is arranged to close the second oil return means (17) when a pressure difference threshold at the counter-pressure switching valve (41) is exceeded.

4. A ventilation device (10) according to claim 3, characterized in that the counter-pressure switching valve (41) of the second oil return means (17) has a throttling bypass (42).

5. The ventilation device (10) according to one of the preceding claims, characterized in that the second oil return means (17) have a check valve (43).

6. The ventilation device (10) according to one of the preceding claims, characterized in that the second oil return means (17) have a throttle (44).

7. The ventilation device (10) according to one of the preceding claims, characterized in that the first oil return means (16) have a throttle valve (44).

8. The ventilation device (10) according to one of the preceding claims, characterized in that the ventilation device (10) has a throttle valve (45) and/or a pressure regulating valve (46) after the exhaust opening (15) of the oil separator (20).