Compressor for supercharging a combustion engine

Abstract

The invention discloses a compressor for supercharging a combustion engine, the compressor comprising: a compressor housing (1) having a volute (2); a compressor impeller (3) arranged in the compressor housing (1), the compressor impeller (3) rotating about an axis (A) and transporting gas into the volute (2); and an inlet passage (4), at least an end portion of the inlet passage (4) being oriented in the direction of the axis (A) so as to direct gas towards the compressor impeller in the axial direction, wherein an exhaust passage (5) terminates in the inlet passage (4) upstream of the compressor impeller (3), and wherein the exhaust passage (5) can be closed by means of a valve (6), wherein a housing (8) of a drive device (7) of the valve (6) is integrally formed with the compressor housing (1).

Description

Field of the Invention

[0001] The present invention relates to a compressor for supercharging a combustion engine. Background Art

[0002] DE 11 2006 003 468 T5 describes a compressor having a valve for exhaust gas recirculation (EGR-valve) and a mixing device. The EGR-valve is only schematically shown. The exhaust gas flows along a circular path in the volute around the axis of the compressor impeller. Along its circular path in the volute, the exhaust gas flow can successively enter the inlet passage of the compressor by radially inwardly passing through an annular opening, and the inlet passage is arranged to be collinear with the axis of the compressor impeller.

[0003] It is an object of the present invention to provide a compressor for supercharging a combustion engine, in which exhaust gas recirculation is integrally formed with the compressor and the EGR valve operates reliably. Summary of the Invention

[0004] For a compressor for supercharging a combustion engine as mentioned at the beginning, according to the present invention, this object is achieved by the present application.

[0005] By integrally forming the housing of the drive device of the valve with the compressor housing, a safe and precise positioning of the structure for driving the valve is achieved.

[0006] Furthermore, the integral formation allows a compact and space-saving design of the entire compressor. Even further, the number of parts to be assembled can be reduced.

[0007] The compressor in the sense of the present invention relates to any compressor for supercharging a combustion engine. Particularly preferably, the compressor impeller can be driven by an exhaust gas turbine, and the compressor is part of a turbocharger. Alternatively, the compressor impeller can be driven by an electric motor or by other drive means.

[0008] Via the inlet passage, fresh air or any suitable gas is guided to the compressor impeller. The air or gas is then compressed by the compressor. Downstream of the compressor, the air or gas is supplied into the intake system of the combustion engine.

[0009] Via an exhaust passage terminating in the inlet passage upstream of the compressor impeller, an optional exhaust gas recirculation of the combustion engine can be added to the air or gas in the inlet passage upstream of the compressor impeller. The amount of the added exhaust gas can be adjusted by a valve. The valve can have the function of an EGR-valve of an exhaust gas recirculation system known in the art.

[0010] The housing of the drive device and the compressor housing can generally be composed of separate parts, which are assembled to form an integral unit.

[0011] In a particularly preferred embodiment of the present invention, the compressor housing and the housing of the drive device are provided as a one-piece, particularly as a casting. This also includes embodiments in which the first part of the compressor housing and the first part of the housing of the drive device are provided as a one-piece.

[0012] Generally preferably, the valve can include a slider movable in a linear direction, or a valve body / flap that can be rotated by a rotatable shaft. The combination of the two principles is also within the scope of the present invention.

[0013] To provide an effective and space-saving construction, the valve preferably includes the shaft of the slider or the valve body, wherein the direction of movement of the slider or the axis of rotation of the shaft has an angle of at least 30°, preferably at least 60°, with the axis of the compressor impeller. Most preferably, the slider or the shaft is oriented substantially perpendicular to the axis of the compressor impeller.

[0014] In a generally preferred embodiment of the present invention, the exhaust passage terminates in the inlet passage at least by means of a first orifice, wherein the projection of the orifice along the main flow direction of the exhaust has a region concentration, and the region concentration has a radial offset with respect to the axis of the compressor impeller in the main flow direction of the exhaust. This arrangement allows for the hydrodynamic optimization of the gases to be mixed.

[0015] In this regard, it may be beneficial if the exhaust and fresh air are mixed as little as possible before entering the compressor. This low mixing dynamics can prevent the unwanted condensation of corrosive liquids from the exhaust, because the exhaust is usually cooled when mixed with the fresh air from the inlet passage.

[0016] It should be noted that the arrangement described in the prior art DE 11 2006 003 468 T5 cited above provides a maximum mixing of the exhaust and fresh air before entering the compressor. In this arrangement, the annular orifice is generally arranged to be substantially tangent to the main flow direction of the exhaust. Therefore, the area of this orifice along the main flow direction of the exhaust is zero, and there is no defined region concentration.

[0017] In another optimized embodiment of the present invention, the radial offset is greater than 2% of the near diameter of the inlet passage upstream of the orifice, preferably greater than 5%, and more preferably between 5% and 50%.

[0018] In the case of a particularly preferred embodiment of the present invention, further, the exhaust passage terminates in the inlet passage by means of a second orifice, which is arranged at the end of a branch passage that has branched off from the exhaust passage. By this design, an undesired early mixing of the exhaust gas and air in the inlet passage can be further reduced.

[0019] To optimize the fluid dynamics of such an embodiment, the branch passage can extend around the circumference of the inlet passage by more than 30°, in particular between 30° and 210°.

[0020] In the case of a further preferred embodiment, the gas flow through the first orifice and the gas flow through the second orifice enter the inlet passage in substantially opposite directions, wherein the gas flows compensate for the corresponding tilting momentum occurring on the compressor impeller. This design minimizes the undesired forces exerted by the increased exhaust gas on the compressor impeller.

[0021] In a generally preferred embodiment of the present invention, a heating device can be provided for heating the valve. Such a heating device can be activated particularly in cold start situations, since modern exhaust gas recirculation is enabled very early or immediately upon starting of the combustion engine. In this case, the heating device can be used to prevent the blockage of the valve due to the freezing of the water content of the exhaust gas.

[0022] In a specific embodiment, the heating device can include a passage for a heating fluid, in particular engine coolant. Alternatively or additionally, the heating device can include an electric heating part.

[0023] Further advantages and features of the present invention are described in the embodiments of the present invention described below.

[0024] Two preferred embodiments of the present invention are described below and further illustrated with the aid of the drawings. Description of the Drawings

[0025] Figure 1 A spatial and partial cross-sectional view of a compressor according to a first embodiment of the present invention is shown.

[0026] Figure 2 Shows a Figure 1 detail of the compressor viewed from different angles.

[0027] Figure 3 Shows a Figure 1 further detail of the compressor viewed from different angles.

[0028] Figure 4 Is shown in a plan view along the axis direction of the compressor impeller Figure 1The exhaust passage of the compressor.

[0029] Figure 5 shows Figure 1 a detail of a compressor having a valve and a drive device.

[0030] Figure 6 shows another detail of the Figure 1 compressor as viewed from different angles. DETAILED DESCRIPTION

[0031] Figure 1 The device in [[ ]] shows a compressor according to the present invention. The compressor is designed to supercharge a combustion engine. The compressor includes a compressor housing 1 having a volute 2. A compressor impeller 3 is arranged in the compressor housing 1. During operation, the compressor impeller 3 rotates about an axis A and transports gas into the volute 2.

[0032] An inlet passage 4 is oriented in the direction of the axis A so as to direct gas axially along the direction A towards the compressor impeller 3. In [[ ]], the fully shown inlet passage 4 is a straight pipe section, but in other embodiments, the inlet passage may have various different forms. However, at least the end portion of the inlet passage will direct gas axially towards the compressor impeller. Figures 1 to 3 In [[ ]], the fully shown inlet passage 4 is a straight pipe section, but in other embodiments, the inlet passage may have various different forms. However, at least the end portion of the inlet passage will direct gas axially towards the compressor impeller.

[0033] An exhaust passage 5 terminates in the inlet passage 4 upstream of the compressor impeller 3. A valve 6 is provided in the exhaust passage 5, wherein the exhaust passage 5 can be closed by means of the valve 6.

[0034] The valve 6 has a drive device 7 (see [[ ]], [[ ]]), the drive device being for changing the open state of the valve 6. The housing 8 of the drive device 7 of the valve 6 is integrally formed with the compressor housing 1. Figure 5 , Figure 6 )

[0035] By integrally forming the housing 8 of the drive device 7 of the valve 6 with the compressor housing, a safe and precise positioning of the structure 8 for driving the valve is achieved. In addition, the integral formation allows for a compact and space-saving design of the entire compressor. Even further, the number of parts to be assembled can be reduced.

[0036] As [[ ]] Figure 1 shown, the compressor is a compressor for supercharging a combustion engine. The compressor impeller is driven by an exhaust turbine (not shown), and the compressor is part of a turbocharger. In an alternative embodiment, the compressor impeller 3 can also be driven by an electric motor, or by other drive means.

[0037] Via the inlet passage 4, fresh air or any suitable gas is guided to the compressor impeller 3. The air or gas is then compressed by the compressors 2, 3. Downstream of the compressor, the air or gas is fed to the intake system (not shown) of the combustion engine.

[0038] Via an exhaust passage 5 which terminates in the inlet passage 4 upstream of the compressor impeller 3, an optional exhaust gas recirculation of the combustion engine can be added to the air or gas in the inlet passage 4 upstream of the compressor impeller 3. The amount of the added exhaust gas can be adjusted by means of a valve 6. The valve 6 has the function of an EGR-valve of an exhaust gas recirculation system known in the art.

[0039] The housing 8 of the drive device 7 and the compressor housing 1 form an integral unit. In the present embodiment of the invention, the compressor housing 2 and the housing 8 of the drive device 7 are provided as one piece and are provided as a casting. It should be noted that the housing 8 further includes a cap 8a, and the compressor housing 2 can also include additional parts (not shown) to be attached.

[0040] In the case of the present embodiment, the valve 6 includes a valve body 6a in the form of a valve flap. The valve flap 6a can be rotated by a rotatable shaft 6b. The shaft 6b is precisely supported in a hole which connects the exhaust passage 5 to the interior of the housing 8 of the drive device 7. This precise support provides a precise position and movement for the valve body 6a.

[0041] To provide an effective and space-saving construction, the direction of the axis of rotation of the shaft 6b has an angle of at least 30°, preferably at least 60°, with the axis A of the compressor impeller 3. In the present embodiment, the shaft 6b is oriented substantially perpendicular to the axis A of the compressor impeller 3.

[0042] The exhaust passage 5 terminates in the inlet passage 4 via a first orifice 9, wherein the projection of the orifice 9 along the main flow direction S of the exhaust gas has a region concentration F, and the region is radially offset D with respect to the axis A of the compressor impeller in the main flow direction S of the exhaust gas. This arrangement allows the hydrodynamic optimization of the gases to be mixed.

[0043] For the present embodiment of the invention, it is beneficial that the exhaust gas and the fresh air are mixed as little as possible before entering the compressor impeller 3. This low mixing dynamics prevents the undesired condensation of corrosive liquids from the exhaust gas, since the exhaust gas is usually cooled when mixed with the fresh air from the inlet passage.

[0044] It should be noted that the arrangement as described in the prior art DE 11 2006 003 468 T5 cited above provides a maximized mixing of the exhaust gas and fresh air before entering the compressor. In this arrangement, the annular orifice is generally arranged to be substantially tangential to the main flow direction of the exhaust gas. Therefore, the area of this orifice in the main flow direction of the exhaust gas is zero, and there is no defined area concentration.

[0045] In this example of the present invention, the radial offset D is approximately 25% of the diameter W of the inlet channel 4 near the orifice 9 upstream. Therefore, the offset D is greater than 2% of the diameter W of the inlet channel 4, even greater than 5%, and between 5% and 50%.

[0046] It should be noted that in this design, as Figure 4 best visible in, the projection P of the first orifice 9 in the main flow direction S extends from a line that is close to and crosses the center of the inlet channel 4 to the wall of the inlet channel 4. Although P is actually a projected area, in the Figure 4 cross-sectional view of, P appears as a line. It should be noted that in other embodiments, the size, shape, and position of the orifice 9 can be different.

[0047] Furthermore, the exhaust gas channel 5 terminates in the inlet channel 4 by means of a second orifice 10. The second orifice 10 is arranged at the end of a branch channel 11 that has branched off from the exhaust gas channel 5. With this design, the undesired early mixing of the exhaust gas and air in the inlet channel can be further reduced.

[0048] To optimize the hydrodynamics of this embodiment, the branch channel 11 extends around the circumference of the inlet channel 4 by an angle C of approximately 80°. Therefore, this angle exceeds 30°, and is between 30° and 210°.

[0049] In this way, the gas flows of the first orifice 9 and the second orifice 10 enter the inlet channel 4 in substantially opposite directions, wherein the gas flows compensate for the corresponding inclined momentum occurring on the compressor impeller 3. This design minimizes the undesired forces exerted by the increased exhaust gas on the compressor impeller 3.

[0050] As can be seen especially in Figure 3 and Figure 2 in the detailed views, the two orifices 9, 10 have different positions not only in the circumferential direction of the inlet channel 4 but also in the direction of the axis A of the compressor impeller. The edge of the second orifice 10 is positioned closer to the compressor impeller 3 by a distance L than the corresponding edge of the first orifice 9, and this second orifice terminates the entire path of the exhaust gas flow for a longer time. The distance L is less than the width W of the inlet channel 4, and is currently approximately 25% of the width.

[0051] Figure 6A schematic view of a second embodiment of the present invention is shown. In this embodiment, a heating device 12 is provided for heating the valve 6. The heating device 12 can be activated especially in cold start situations, since modern exhaust gas recirculation is activated very early or immediately with the start of the combustion engine. In this case, the blockage of the valve caused by the freezing of the water content of the exhaust gas can be prevented by means of the heating device.

[0052] Figure 6 The heating device in includes an electric heating part. The heating resistance wire is placed close to and upstream of the valve 6 in the exhaust passage 5. The electric heating wire is heated by an electric current, thus providing rapid temperature rise. In another embodiment (not shown), the heating device may alternatively or additionally include a passage for a heating fluid, especially engine coolant.

[0053] It should be understood that the electrically heated device 12 and / or any other heating device (such as a passage for a heating fluid) schematically shown can be designed to heat the exhaust gas upstream of the valve, as well as the exhaust passage 5, and / or the valve body 6a, and / or the valve shaft 6b. The effect of any such heating is to prevent water droplets or condensate from the exhaust gas from depositing as ice near the valve 6, thus ensuring proper mechanical function of the valve even in cold start situations at temperatures below 0 °C.

[0054] List of references

[0055] 1 Compressor housing

[0056] 2 Volute of the compressor

[0057] 3 Compressor impeller

[0058] 4 Inlet passage

[0059] 5 Exhaust passage

[0060] 6 Valve

[0061] 6a Valve flap / valve body

[0062] 6b Shaft of the valve body

[0063] 7 Drive device

[0064] 8 Housing of the drive device

[0065] 8a Cap of the housing

[0066] 9 First orifice

[0067] 10 Second orifice

[0068] 11 Branch passage

[0069] 12 Heating device

[0070] The axis of a compressor impeller

[0071] The angular length of the C branch channel

[0072] D Radial offset

[0073] F The area concentration of the first orifice

[0074] L The distance in the axial direction

[0075] P The projection of the first orifice

[0076] S The main flow direction of the exhaust

[0077] W The diameter of the inlet channel

Claims

1. A compressor for supercharging a combustion engine, the compressor comprising: A compressor housing (1), the compressor housing having a volute (2), A compressor impeller (3), the compressor impeller being disposed in the compressor housing (1), the compressor impeller (3) rotating about an axis (A) and transporting gas into the volute (2), and An inlet passage (4), at least an end portion of the inlet passage (4) being oriented in the direction of the axis (A) so as to direct gas along the direction of the axis towards the compressor impeller, Wherein, an exhaust passage (5) terminates in the inlet passage (4) upstream of the compressor impeller (3), Wherein, the exhaust passage (5) can be closed by means of a valve (6), the valve (6) comprising a shaft (6b) of a valve body (6a), and Wherein, a housing (8) of a drive device (7) of the valve (6) is integrally formed with the compressor housing (1), Characterized in that the compressor housing (1) and the housing (8) of the drive device (7) are provided as a one-piece, The shaft (6b) is supported in a hole connecting the exhaust passage (5) to the interior of the housing (8) of the drive device (7).

2. The compressor according to claim 1, characterized in that, The direction of the axis of rotation of the shaft (6b) has an angle of at least 30° with the axis (A) of the compressor impeller (3).

3. The compressor according to claim 1, wherein The exhaust passage (5) terminates in the inlet passage (4) at least by means of a first orifice (9), wherein a projection (P) of the first orifice (9) along the main flow direction (S) of the exhaust has a region concentration portion (F), and the region concentration portion has a radial offset (D) relative to the axis (A) of the compressor impeller (3) in the main flow direction of the exhaust.

4. The compressor according to claim 3, wherein The radial offset (D) is greater than 2% of the near diameter (W) of the inlet passage (4) upstream of the first orifice (9).

5. The compressor according to claim 3 or 4, characterized in that, The exhaust passage (5) also terminates in the inlet passage (4) by means of a second orifice (10), the second orifice (10) being provided at the end of a branch passage (11) that branches off from the exhaust passage (5).

6. The compressor according to claim 5, wherein, The branch passage (11) extends around the circumference of the inlet passage (4) by more than 30°.

7. The compressor according to claim 5, characterized in that, The gas flow of the first orifice (9) and the gas flow of the second orifice (10) enter the inlet passage (4) in substantially opposite directions, and the gas flows of the first orifice (9) and the second orifice (10) compensate for the corresponding inclined momenta occurring on the compressor impeller (3).

8. The compressor according to claim 1, characterized in that, A heating device (12) is provided for heating the valve (6).

9. The compressor according to claim 8, characterized in that, The heating device includes a passage for a heating fluid.

10. The compressor according to claim 8, characterized in that, The heating device (12) includes an electric heating part.

11. The compressor according to claim 1, wherein, The compressor housing (1) and the housing (8) of the drive device (7) are provided as castings.

12. The compressor according to claim 2, characterized in that, The direction of the axis of rotation of the shaft (6b) has an angle of at least 60° with the axis (A) of the compressor impeller (3).

13. The compressor according to claim 4, characterized in that, The radial offset (D) is greater than 5% of the near diameter (W) of the inlet passage (4) upstream of the first orifice (9).

14. The compressor according to claim 13, characterized in that, The radial offset (D) is between 5% and 50% of the near diameter (W) of the inlet passage (4) upstream of the first orifice (9).

15. The compressor according to claim 6, characterized in that, The branch passage (11) extends circumferentially around the inlet passage (4) between 30° and 210°.

16. The compressor according to claim 9, wherein, The heating fluid is engine coolant.

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