Suction device for crankcase ventilation

Abstract

The invention enables an adequate crankcase negative pressure in an internal combustion engine, in all operating ranges to the extent possible and using a suction device for the crankcase ventilation of an internal combustion engine, which suction device is equipped with a housing, a controllable electric motor and a compressor for conveying crankcase gas, which compressor is driven by the electric motor, the compressor having connection points for a crankcase ventilation line, such that the crankcase pressure of the internal combustion engine is controllable by controlling the electric motor.

Claims

1. Suction device for crankcase ventilation of an internal combustion engine, comprising a housing having a wall, a controllable electric motor and a compressor driven by the electric motor for conveying crankcase gas, the compressor having an impeller and connection points for a crankcase ventilation line, such that the crankcase pressure of the internal combustion engine is controllable by controlling the electric motor, wherein the compressor and the electric motor at least partially overlap one another axially, the compressor surrounding the electric motor radially outwardly at least in sections, the electric motor has an externally running rotor which is coupled to the impeller of the compressor, and the compressor is configured as a side channel compressor.

2. Suction device according to claim 1, characterized in that the housing has one or more cooling fins projecting outwardly on a housing section facing away from the compressor.

3. Suction device according to claim 1, characterized in that an electronic control for the electric motor-is provided which adjoins the housing section equipped with cooling fins, with at least partial surface contact with the wall of the housing section.

4. Suction device according to claim 1, characterized in that the housing has a holder for attachment on a housing section facing away from the compressor and/or on a housing section bordering the compressor on the outside.

5. A crankcase ventilation for discharging crankcase gas of an internal combustion engine comprising a suction device comprising: a housing, a controllable electric motor, and a compressor driven by the electric motor for conveying crankcase gas, the compressor having an impeller and connection points for a crankcase ventilation line, such that the crankcase pressure of the internal combustion engine is controllable by controlling the electric motor, wherein the compressor and the electric motor at least partially overlap one another axially, the compressor surrounding the electric motor radially outwardly at least in sections, the electric motor has an externally running rotor which is coupled to the impeller of the compressor, and the compressor is configured as a side channel compressor.

6. An internal combustion engine comprising: a. a crankcase ventilation for discharging crankcase gas of an internal combustion engine comprising a suction device, wherein the suction device comprises: a housing, a controllable electric motor, and a compressor driven by the electric motor for conveying crankcase gas, the compressor having an impeller and connection points for a crankcase ventilation line, such that the crankcase pressure of the internal combustion engine is controllable by controlling the electric motor, wherein the compressor and the electric motor at least partially overlap one another axially, the compressor surrounding the electric motor radially outwardly at least in sections, the electric motor has an externally running rotor which is coupled to the impeller of the compressor, and the compressor is configured as a side channel compressor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The description will be explained in more detail below with reference to the drawings, identical or functionally equivalent elements being provided only once with reference signs if necessary. In the drawings:

(2) FIG. 1 is an exemplary embodiment of a suction device in a perspective view;

(3) FIG. 2 is the suction device from FIG. 1 in a further perspective view according to arrow A in FIG. 1;

(4) FIG. 3 is the suction device from FIG. 1 in a side view according to arrow B in FIG. 1;

(5) FIG. 4 is the suction device from FIG. 1 in a sectional view along the section axis C-C in FIG. 3;

(6) FIG. 5 is the suction device from FIG. 1 in a sectional view along the section axis D-D in FIG. 3; and

(7) FIG. 6 is an exemplary embodiment of a crankcase ventilation and an internal combustion engine having a suction device in a schematic diagram.

DETAILED DESCRIPTION

(8) FIG. 1 shows a suction device for crankcase ventilation of an internal combustion engine and is designated overall by reference sign 10. The suction device 10 has a housing 12, a controllable electric motor 14 (see FIG. 4) and a compressor 16 driven by the electric motor 14 for conveying crankcase gas (see FIG. 1). The electric motor 14 is arranged in the housing 12.

(9) The compressor 16 has connection points 18, 20 for connection to a crankcase ventilation line 102 (see FIG. 6). Thus, by controlling the electric motor 14, in particular by controlling its engine speed, the crankcase pressure of the internal combustion engine may be controlled.

(10) The connection point 18 is an output from the compressor 16 (see FIG. 1). The connection point 20 serves as an input into the compressor 16. A section of a crankcase ventilation line may be connected at the connection point 20, which connects the crankcase of the internal combustion engine to the connection point 20 of the compressor 16 (flow connection). A section of a crankcase ventilation line may be connected at the connection point 18, which connects the connection point 18 to the intake tract of the internal combustion engine (flow connection). The connection points 18, 20 open into the compressor channel 22 of the compressor 16 (see FIG. 4).

(11) The housing 12 has a plurality of separate housing sections, each one adjoining the other at parting planes and collectively forming the housing 12. In the present case, the housing 12 has four housing sections 24, 26, 28, 30 which adjoin one another at three mutually parallel separation planes 32, 34, 36. The housing sections 24, 26, 28, 30 are fastened to one another, for example glued and/or screwed.

(12) The first housing section 24 outwardly delimits the compressor channel 22 to one side of the housing 12. Part of the compressor channel 22 (side channel 38) is formed in the first housing section 24. The compressor 16 is configured as a side channel compressor. In addition, the first housing section 24 delimits a receiving space 40 for the electric motor 14. The connection points 18, 20 are formed on the first housing section 24 and open into the compressor channel 22 (see FIGS. 1 and 2). A holder 42 for fastening the suction device 10 is also formed on the first housing section 24 and protrudes outwardly from the first housing section 24.

(13) The second housing section 26 delimits the compressor channel 22 on the inside relative to the housing 12 (see FIG. 4). The impeller 41 of the compressor 16 is arranged in the part of the compressor channel 22 formed in the second housing section 26. In addition, the electric motor 14 arranged in the receiving space 40 is fastened to the second housing section 26.

(14) The impeller 41 is shown in FIG. 5. The impeller 41 has a plurality of blades 43 which divide the impeller 41 into a plurality of chambers 45.

(15) The third housing section 28 has a partition 44 and separates the interior of the second housing section 26 from the interior of the fourth housing section 30 (see FIG. 4).

(16) The fourth housing section 30 delimits the housing 12 on the side facing away from the compressor 16. In addition, the fourth housing section 30 delimits a further receiving space 46, in which an electronic control 48 for the electric motor 14 is arranged, for example an assembled printed circuit board. In addition, two holders 50, 52 for fastening the suction device 10 are formed on the fourth housing section and project outwardly from the fourth housing section 30. In addition, outwardly projecting cooling fins 54 are formed on the fourth housing section 30 (see FIGS. 2 and 4).

(17) The electronic control 48 for the electric motor 14 adjoins the fourth housing section 30 equipped with cooling fins 54 (see FIG. 4). The electronic control 48, for example an assembled printed circuit board, is in at least partial surface contact with the inside of the wall 55 of the fourth housing section 30.

(18) The compressor 16 and the electric motor 14 overlap at least partially axially, the compressor 16 surrounding the electric motor 14 at least in sections radially outwardly (see FIG. 4). The electric motor 14 has an external rotor 56 and an internal stator 58 (external rotor motor). The rotor 56 is coupled to the impeller 41 of the compressor 16, in particular in a rotationally fixed manner.

(19) The electric motor 14 has a preferably cylindrical cap 60 which is non-rotatably coupled to the rotor 56 and is connected to a motor shaft 62. The cap 60 has a wall 64 which is arranged radially between the rotor 56 and the compressor impeller 41, in particular contact sections 66 of the compressor impeller 41.

(20) The motor shaft 62 is rotatably mounted on the second housing section 26 by means of bearings 68, 70, for example roller bearings. A sealing is produced on the motor shaft 62 via a seal 72, in particular a radial shaft sealing ring. The rotor 56 is connected in a rotationally fixed manner to the compressor impeller 41 via the wall 64. When the electric motor 14 is driven, the rotor 56 or the compressor impeller 41 rotates about the axis of rotation 74.

(21) The electronic control 48 for the electric motor 14 adjoins the fourth housing section 30 equipped with cooling fins 54. The electronic control 48, for example an assembled printed circuit board, is in at least partial surface contact with the inside of the wall 55 of the fourth housing section 30.

(22) The holder 42 and/or the holders 50, 52 are configured in such a way that heat can be dissipated from the interior of the housing 12. For this purpose, the holders 42, 50, 52 may be metallic and/or have comparatively large wall thicknesses.

(23) As already explained, the housing 12 of the suction device 10 has a plurality of housing sections 24, 26, 28, 30 which adjoin one another at the parting planes 32, 34, 36. The parting planes 32, 34, 36 are in particular oriented orthogonally to the axis of rotation 74 of the electric motor 14 or of the compressor 16.

(24) For improved heat dissipation, one or more, preferably all, housing sections 24, 26, 28, 30 of the suction device 10 are metallic.

(25) As already explained above, the cooling effects achieved enable comparatively inexpensive components to be used for the electric motor 14 and/or electronic control 48. By arranging the electric motor 14 relative to the compressor 16, the electric motor 14 may be cooled by the crankcase gas passing through the compressor 16 (compressor channel 22). In addition, the cooling fins 54 can discharge heat from the interior of the housing 12 that is generated, for example, by the electric motor 14 and/or control 48, to the outside. Heat can be emitted from the interior of the housing 12 to surrounding components, for example to a housing or other components of the internal combustion engine, via the holders 42, 50, 52.

(26) FIG. 6 shows a crankcase ventilation 100 and an internal combustion engine 200.

(27) The crankcase ventilation 100 has a crankcase ventilation line 102, which is configured to connect (establishing a flow connection between the crankcase and the intake tract) the crankcase 202 of an internal combustion engine 200 to its intake tract 204 (e.g. air intake conduit). The connection opens in particular into a section of the intake tract 204 between the air mass meter 218 and the compressor 220 of a turbocharger.

(28) The suction device 10 is connected to the crankcase ventilation line 102 via the connection points 18, 20 on the compressor 16, so that crankcase gas can be conveyed from the crankcase 202 to the intake tract 204 by means of the suction device 10. The crankcase pressure in the internal combustion engine 200 may be controlled by controlling the electric motor 14 that drives the compressor 16.

(29) In the crankcase ventilation line 102, one or more oil mist separators 104, 106, for example a part-load separator 106 and a full-load separator 104, may be situated upstream of the suction device 10. Oil separated there may be returned via an oil return line (not shown) to the internal combustion engine 200, for example to its oil sump 206.

(30) The internal combustion engine 200 has a crankcase ventilation 100 for discharging crankcase gas from the crankcase 202 as described above. The crankcase ventilation 100 has a suction device 10 for crankcase ventilation as described above.

(31) The internal combustion engine 200 has further components. First of all, the internal combustion engine 200 has an intake tract 204 (air intake or supply line) and an exhaust tract 208 (exhaust gas line or discharge line). The intake tract 204 may extend from an air intake point 210 to the combustion chamber 212. The exhaust tract 208 may extend from the combustion chamber 212 to an exhaust gas discharge point 214 (e.g. exhaust muffler).

(32) One or more of the following components are preferably provided in the intake tract 204: air filter 216, air mass meter 218 (e.g. hot film air mass meter), compressor unit 220 (e.g. compressor side of a turbocharger), charge air cooler 222, throttle valve 224.

(33) A turbine unit 226 (turbine side of a turbocharger) may be provided in the exhaust tract 208. The turbine wheel of the turbine unit 226 may in particular be coupled in a rotationally fixed manner to the compressor wheel of the compressor unit 220 by means of a shaft 228.