SIDE CHANNEL BLOWER HAVING A PLURALITY OF FEED CHANNELS DISTRIBUTED OVER THE CIRCUMFERENCE

Abstract

A side channel blower for an internal combustion engine includes a housing comprising an inlet, an outlet, a first housing part, and a second housing part. The inlet and the outlet are fluidically connected via an inlet region, via at least one feed channel which extends at least partially in an annular shape in at least one of the first housing part and the second housing part, and via an outlet region. An impeller is rotatably mounted in the housing and is driven via a drive unit. The impeller comprises conveying blades which interact with a feed channel arranged opposite thereto. At least one interruption region is arranged between the inlet region and the outlet region. The at least one interruption region is configured to interrupt the at least one feed channel in a circumferential direction. The at least one feed channel comprises a circumferential angle of <300°.

Description

CROSS REFERENCE TO PRIOR APPLICATIONS

This application is a U.S. National Phase application under 35 U.S.C. §371 of International Application No. PCT/EP2012/062803, filed on Jul. 2, 2012 and which claims benefit to German Patent Application No. 10 2011 108 763.3, filed on Jul. 28, 2011. The International Application was published in German on Jan. 31, 2013 as WO 2013/013933 A1 under PCT Article 21(2).

FIELD

The present invention relates to a side channel blower, in particular, a secondary air pump for an internal combustion engine, comprising a multi-part housing which has at least one inlet and at least one outlet and has substantially one first and one second housing part, wherein the inlet and the outlet are fluidically connected via at least one inlet region, extending over at least one at least partially annular feed channel formed in the first and/or second housing part and via at least one outlet region, comprising an impeller which is rotatably mounted in the housing and can be driven via a drive unit, wherein the impeller has conveying blades which interact with the opposite feed channel and comprising at least one interruption region between the inlet region and the outlet region, in which the at least one feed channel is interrupted in the circumferential direction

BACKGROUND

Such side channel blowers or pumps are generally known and are described in a large number of applications, for example, in DE 10 2009 006 652 A1. In a motor vehicle, they are used, for example, to convey fuel or to blow secondary air into the exhaust gas system. The drive is typically provided by an electric motor that drives the impeller. The circumference of the impeller is substantially configured such that it forms a circumferential vortex channel together with the axially opposite feed channel. From the part of the impeller that forms the vortex channel, conveying blades extend perpendicularly towards the opposite part of the feed channel that is configured as a housing so that pockets are formed between the conveying blades. When the impeller rotates, the conveyed fluid in the pockets is accelerated by the conveying blades both in the circumferential direction and the radial direction so that a circulating vortex flow is created in the feed channel.

Side channel blowers are known in which only a feed channel is formed on an axial side of the impeller in a housing part, while in other known side channel blowers, a feed channel is formed on both axial sides of the impeller, in which case both feed channels are fluidically connected. In such a side channel blower, one of the feed channels is formed in a housing part serving as a cover, while the other feed channel is formed in the housing part in which, typically, the drive unit is mounted on whose shaft the impeller is fastened for rotation therewith.

It is generally assumed that it is necessary to utilize the largest possible part of the feed channel circumference for an optimum conveying performance or an increase in pressure. For this reason, the inlet and the outlet are spaced as far apart as possible along the circumference, seen in the direction of movement of the impeller, whereby a short-circuit flow between the inlet and the outlet is avoided by an interruption region.

Side channel blowers are here specified for two duty points. First, this is the nominal feed point, e.g., 40 kg/h at 100 mbar, and, second, the zero feed point (feed=0 kg/h). At the zero feed point, however, a substantially higher pressure prevails since in this case, for example, the outlet is completely closed. The difference between the pressures at the zero feed point and the nominal feed point is described as delta-p.

If a new nominal feed point is to be set by adjusting the speed of rotation without changing the geometry of the side channel pump, this inevitably leads to a delta-p that results from the new operating speed and the geometry or the characteristic of the side channel blower. Under certain circumstances, delta-p and thus the power consumption at zero feed, thereby become disproportionately high. It is of course possible to adapt the impeller geometry. In this respect, however, the degrees of freedom are limited and such an adaptation also entails high tooling and development costs.

SUMMARY

An aspect of the present invention is to provide a side channel blower that avoids the disadvantages mentioned above.

In an embodiment, the present invention provides a side channel blower for an internal combustion engine which includes a housing comprising at least one inlet, at least one outlet, a first housing part, and a second housing part. The at least one inlet and the at least one outlet are fluidically connected with each other via at least one inlet region, via at least one feed channel configured to extend at least partially in an annular shape in at least one of the first housing part and the second housing part, and via at least one outlet region. An impeller is configured to be rotatably mounted in the housing and to be driven via a drive unit. The impeller comprises conveying blades configured to interact with a feed channel arranged opposite thereto. At least one interruption region is arranged between the at least one inlet region and the at least one outlet region. The at least one interruption region is configured to interrupt the at least one feed channel in a circumferential direction. The at least one feed channel comprises a circumferential angle of <300°.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is described in greater detail below on the basis of embodiments and of the drawings in which:

FIG. 1 shows a side elevational view of a side channel blower in section;

FIG. 2 shows a perspective view of a first housing part of the side channel blower in FIG. 1;

FIG. 3 shows a perspective view of a second housing part of the side channel blower in FIG. 1; and

FIG. 4 shows an illustration of the characteristics associated with an embodiment in comparison with a conventional side channel blower.

DETAILED DESCRIPTION

The present invention provides at least one feed channel having a circumferential angle of <300°. It should be noted here that the circumferential angle is defined such that the starting point of the circumferential angle is defined by a first contour point of the feed channel and the end point of the circumferential angle is defined by a last contour point of the feed channel. In this manner, the pressure build-up in the side channel blower is reduced so that a side channel blower with a lower maximum pressure is obtained. The power consumption at the zero feed point is thus correspondingly limited. Shifting the nominal feed point cannot lead to an excessively increased power consumption of the side channel blower.

In an embodiment of the present invention, both the first and the second housing part can, for example, each comprise a feed channel having a common outlet, wherein one of the feed channels is substantially smaller than the other feed channel. A side channel blower is thus provided that can reach a relatively high maximum pressure and thus also a relatively high feed point. At the same time, however, the associated characteristic is of a flatter design than the conventional side channel blower, whereby the adverse effect of a change of the nominal feed point on the power consumption is not too great.

In an embodiment of the present invention, at least two feed channels can, for example, be provided in at least one housing part, the feed channels being successive in the circumferential direction and being interrupted by interruption regions, each feed channel being connected with an outlet region.

For constructional reasons, at least two outlets may be provided in such a case, each outlet being connected with an outlet region. In an embodiment of the present invention, two circumferentially successive feed channels can, for example, be provided both in the first and the second housing part, wherein the feed channels extending in parallel with each other in the axial direction each have one outlet region, wherein the outlet regions open into a common outlet. This embodiment provides a side channel blower which theoretically describes two side channel blowers having a high flow rate in total, but a low maximum delta-p. This embodiment is compact and cost-effective to manufacture.

An embodiment of the side channel blower of the present invention is illustrated in the drawings and will be described hereunder.

An embodiment of the side channel blower illustrated in the drawings is a so-called dual volute embodiment where both the first and the second housing part are each provided with two circumferentially successive feed channels, wherein the feed channels extending in parallel with each other in the axial direction each have an outlet region, the outlet regions terminating in a common outlet. The section in FIG. 1 is chosen such that is passes through a feed channel. The side channel blower illustrated in FIG. 1 consists of a two-part housing 2 as well as an impeller 4, for example, for conveying air, rotatably arranged in the housing 2 and driven by a drive unit 3. Via an axial inlet 6, the air reaches an inlet region 8 of a first housing part/cover member 10, which in the present embodiment serves as a cover member of the side channel blower. A cavity 56 is formed in the cover member 10 for the impeller 4. From the inlet region 8, the air then flows into two substantially partially annular feed channels 12, 14, the first feed channel 12 being formed in the cover member 10, while the second feed channel 14 is formed in a second housing part 16 having a central opening 17 in which also a bearing 18 of a drive shaft 19 of the drive unit 3 is arranged on which the impeller 4 is mounted. It should be noted (see also FIGS. 2 and 3) that both the cover member 10 and the second housing part 16 each comprise another feed channel 13, 14 with associated inlet and outlet regions as well as inlets 6, 7 and outlets 20, 21. Air exits through outlet regions 23, 25 terminating in tangential outlets 20, 21 provided at the second housing part 16.

The impeller 4 is arranged between the cover member 10 and the second housing part 16 and has conveying blades 22 provided at its circumference, which are curved and extend in the radial direction, wherein a radially extending circumferential ring 24 divides the conveying blades 22 into a first row axially opposite the first feed channel 12 and a second row axially opposite the second feed channel 14 so that two vortex channels are provided, each formed by one of the feed channels 12, 14 and the part of the impeller 4 facing the same. The outer diameter of the feed channels 12, 14 is slightly larger than that of the outer diameter of the impeller 4 so that there is a fluid communication between the two feed channels 12, 14 outside the outer circumference of the impeller 4 so that an exchange of air can take place between the two feed channels 12, 14. Pockets 26, radially open to the outer side, are thus formed between the conveying blades 22 extending from the circumference of the circumferential ring 24, in which pockets 26 air is conveyed or accelerated so that the pressure thereof is increased over the length of the feed channels 12, 14.

Interruption regions 28, 29, 30, 31 are arranged in the cover member 10 and in the housing part 16 (also see FIGS. 2 and 3) to reliably prevent a short-circuit flow against the direction of rotation of the impeller 4 from the axial inlet 6 to the tangential outlet 20. These interruption regions 28, 29, 30, 31 interrupt the feed channels 12, 13, 14, 15 so that a smallest possible gap exists in the interruption regions 28, 29, 30, 31 axially opposite the conveying blades 22 of the impeller 4. Interruption regions 32 are further formed on a radially delimiting wall 33 of the second housing part 16 and interrupt a radially outer connecting region 35 between the individual feed channels 12, 13, 14, 15.

As shown in FIGS. 2 and 3, the feed channels 12, 13 and 14, 15 arranged in the cover member 10 and the second housing part 16, respectively, are of a substantially constant width and, except for the interruption regions 28, 29 and 30, 31, extend along the circumference of the cover member 10 and the housing part 16. In the view shown in FIG. 2, the impeller 4 thus rotates counterclockwise from the inlet region to the end of the feed channel. All feed channels 12, 13, 14, 15 illustrated have a circumferential angle of about 150°. In a side channel blower with a single impeller, two independent volutes are thus disposed, each having two feed channels 12, 13 and 14, 15. Although in the present embodiment two inlets 6, 7 with the associated inlet regions 8, 9 are provided, it is also conceivable, using an appropriate flow guidance, to provide only one inlet or outlet with split associated regions.

FIG. 4 shows the effects of such a side channel blower of the present invention in a characteristic map. FIG. 4 shows two diagrams, one representing the mass flow and the other representing the power consumption, both in relation to delta-p. 36 identifies the development of the characteristic for a side channel blower known from prior art. As delta-p increases, the mass flow decreases and power consumption increases up to the zero feed point. When it is intended to raise a nominal feed point 44 to a nominal feed point 45, this is achieved in the prior art by increasing the speed of rotation, which inevitably leads to an increased power consumption at the zero feed point. This is illustrated by the reference numeral 38. At 40, a side channel blower is represented whose two feed cannels have a shortened circumferential angle. The characteristic of mass flow/delta-p is significantly steeper. With a nominal feed point 46 slightly lower with respect to mass flow, this leads to a substantial reduction in power consumption at the zero feed point. 42 defines the dual volute design described in the embodiment. At a nominal feed point 47, which corresponds to the nominal feed point 47 with respect to the nominal feed point 46, this design has an even steeper characteristic in the mass flow/delta-p characteristic map. The power consumption at the nominal feed point 47 is slightly increased in the present embodiment relative to the characteristic 38, while, however, the power consumption at the zero feed point is significantly reduced.

The present invention is not limited to embodiments described herein; reference should be had to the appended claims.

Claims

1-5. (canceled)

6. A side channel blower for an internal combustion engine, the side channel blower comprising:

a housing comprising at least one inlet, at least one outlet, a first housing part, and a second housing part, the at least one inlet and the at least one outlet being fluidically connected with each other via at least one inlet region, via at least one feed channel configured to extend at least partially in an annular shape in at least one of the first housing part and the second housing part, and via at least one outlet region;

a drive unit;

an impeller configured to be rotatably mounted in the housing and to be driven via the drive unit, the impeller comprising conveying blades configured to interact with a feed channel arranged opposite thereto; and

at least one interruption region arranged between the at least one inlet region and the at least one outlet region, the at least one interruption region being configured to interrupt the at least one feed channel in a circumferential direction,

wherein, the at least one feed channel comprises a circumferential angle of <300°.

7. The side channel blower as recited in claim 6, wherein the first housing part and the second housing part each comprise a feed channel, the feed channels comprise a common outlet, and one feed channel is smaller than the other feed channel.

8. The side channel blower as recited in claim 6, wherein at least one of the first housing part and the second housing part comprises at least two feed channels arranged to be successive to each other in a circumferential direction, the at least two feed channels are separated by the interruption regions, and each of the at least two feed channels is connected with an outlet region.

9. The side channel blower as recited in claim 8, further comprising at least two outlets.

10. The side channel blower as recited in claim 9, wherein each of the first housing part and the second housing part comprises at least two feed channels arranged to be successive to each other in a circumferential direction, the feed channels which extend parallel to each other in an axial direction each comprise an outlet region, and the outlet regions end in a common outlet.