Title of Invention

MASS FLOW SENSOR DEVICE WITH A FLOW GUIDING CHANNEL

Abstract

A mass flow sensor device for at least a partial arrangement in a main channel (2) displays a mass flow sensor (1), in which a mass flow flows in the main direction of Flow. The mass flow sensor (1), which has a bypass channel (7) which displays an inlet section (9) can send current via the mass flow from the main channel (2) into the bypass channel (7). Furthermore, at leas st one mass flow sensing element (17,19) is proposed, by means of which a characteristic variable can be registered for the mass flow in the main channel (2). A flow guiding channel (23) is proposed which has an inlet cross section (25) running perpendicular to the main direction of flow (3) and which features a maximum one third overlap relative to the inlet cross section (25). The inlet cross section (25) is essentia lly arraanged in the middle of the main channel (2). The flow guid ding channel (23) is designed and arranged in such a way that it leads the flow medium at least partially to the inlet section (9) of the mass flow sensor (1), and has at least one passage (29) to the main channel (2) either outside the region of the overlap or in the region of the outlet cross section (27), by which communication with the main channel (2) occurs while bypassing the bypass channel (7).

Full Text

Description MASS FLOW SENSOR DEVICE WITH A FLOW GUIDING CHANNEL The invention relates to a mass flow sensor device. Such mass flow sensor devices are suitable for sensing a mass flow in a main channel. Such a main channel can be, for example, an intake tract of an internal combustion engine. Control of, for example, an internal combustion engine or else diagnostics can be carried out as a function of the mass flow which is sensed by the mass flow sensor device. For these purposes, it is important to sense the actual mass flow reliably and as precisely as possible even under different operating conditions. DE 100 11 709 A1 discloses a mass flow sensor device which is arranged in a main channel and is assigned a pipe body which is assigned coaxially to the main channel. Corresponding mass flow sensor devices with at least one pipe body which is arranged parallel to a main flow direction in the main channel are also known from DE 100 355 43 Al and DE 197 35 664 A1. DE 101 54 253 Al discloses a mass flow sensor device with a vane-shaped shielding body which shields the air mass flow sensor against particles and feeds air to it from the outer wall of the pipe. Here, the mass flow is extracted asymmetrically in the main channel. The object of the invention is to provide a mass flow sensor device which can be operated precisely and reliably. The object is achieved by means of the features of patent claim 1. Advantageous refinements of the invention are characterized in the subclaims. The invention is defined by a mass flow sensor device for at least partial arrangement in a main channel in which a mass flow flows in a main flow direction. The mass flow sensor device has a mass flow sensor with a bypass channel which has an inlet via which mass flow can flow out of the main channel into the bypass channel. In addition, the mass flow sensor has at least one mass flow sensor element by means of which a variable which is characteristic of the mass flow into the bypass channel can be sensed. A flow guiding channel is provided whose inlet cross section, which runs perpendicularly with respect to the main flow direction, has, with its outlet cross section which runs perpendicularly with respect to the main flow direction, a maximum overlap of a third with respect to the inlet cross section. In this context, the maximum overlap refers to the respective projection of the inlet and outlet cross sections onto one another. The inlet cross section is arranged essentially centrally in the main channel. The flow guiding channel is embodied and arranged in such a way that said channel directs at least some of the medium flowing in it to the inlet of the mass flow sensor and has at least one cutout toward the main channel, via which cutout communication occurs with the main channel by bypassing the bypass channel. This cutout can be embodied, for example, outside the region of the overlap or in the region of its outlet cross section. In particular, the outlet cross section is positioned upstream of the inlet of the bypass channel in the main flow direction, and is, if appropriate, embodied so as to be separate from the inlet. It is particularly advantageous that the inlet cross section and outlet cross section do not overlap at all. By means of the flow guiding channel in conjunction with the at least one cutout it is easily possible to ensure that particles such as, for example, dust or else water droplets which are located in the flowing medium can be separated off to a large extent at a wall of the flow guiding channel by means of centrifugal force separation, and can be carried off via the at least one cutout into the main channel by bypassing the bypass channel. As a result, the measurement behavior of the sensor element is then unaffected by these particles, and can therefore be very precise and also reliable. Furthermore, the extraction of the mass flow which occurs essentially centrally in order to feed to the bypass channel permits very robust sensing of the mass flow in the main channel, in particular even when there are inhomogeneous flow profiles in the main channel, such as is generally the case, for example, directly downstream of air filters. As a result, dependence of the measurement signal of the mass flow sensor element on an installation angle with respect to the pipe cross section of the main channel can also be significantly reduced. According to one advantageous refinement, the flow guiding channel has a pipe longitudinal axis which is tilted with respect to the main flow direction. In this way, the flow guiding channel can be implemented particularly easily. According to a further advantageous refinement of the invention, the flow guiding channel is assigned a fastener for securement in the main channel, which fastener is embodied in such a way that it shields the mass flow sensor from the flow in the main channel in a region of the mass flow sensor which is at the end side with respect to the main flow direction. In this way, it is possible, for example, to prevent very effectively the ingress of undesired particles such as, for example, water droplets along, for example, a housing of the mass flow sensor, which can otherwise occur, for example, by means of a creepage process. In this context, the fastener can, in particular, also advantageously be made streamlined and therefore reduce pressure loss. According to a further advantageous refinement of the invention, the fastener has a cutout, medium flowing through which is directed to a temperature sensor element which is provided for sensing the temperature of the flowing medium in the mass flow sensor. In this way it is possible, in particular in conjunction with the shielding effect, for the temperature of the flowing medium to be sensed precisely and largely without delay. According to a further advantageous refinement, the section of the fastener which has a shielding effect with respect to the end side region of the mass flow sensor is embodied first, in the main flow direction, as a narrow web. A non-shielding section of the fastener is embodied so as to widen in relation to the narrow web, at least in part of the main flow direction with respect to said narrow web. In this way, a good flow divider property, which approximates a symmetrical design, can be achieved even with an asymmetrical design of the fastener. According to a further advantageous refinement of the invention, the flow guiding channel is embodied in an S shape. This permits any flow separation to be satisfactorily avoided. According to a further advantageous refinement of the invention, the flow guiding channel is embodied in such a way that its cross section decreases in the flow direction. In this way, stable flow conditions can easily be achieved by accelerating the flow. According to a further advantageous refinement, guide contours are provided in the wall of the flow guiding channel. This has the advantage that the particles which are to be carried away, in particular water droplets and the like, can be guided selectively. According to a further advantageous refinement of the invention, the flow guiding channel is manufactured as an injection molded component in one piece with the main channel. In this way, the mass flow sensor device can be manufactured particularly cost effectively. Exemplary embodiments of the invention are explained in more detail below with reference to the schematic drawings, in which: Figure 1 shows a first longitudinal cross section through a first embodiment of the mass flow sensor device, Figure 2 shows a second longitudinal cross section through the first embodiment of the mass flow sensor device perpendicular to the longitudinal section according to figure 1, Figure 3 shows a cross section through a main channel of the first embodiment of the mass flow sensor device, and Figure 4 shows a longitudinal cross section through a second embodiment of the mass flow sensor device. Elements of identical design or function are characterized with the same reference symbols in all the figures. A mass flow sensor device is provided to be arranged at least partially in a main channel 2. During correct operation of the mass flow sensor device, it is arranged at least partially in the main channel. It can also encompass the main channel, but does not have to. The mass flow sensor device (figure 1) comprises a mass flow sensor which is arranged at least partially in the main channel 2. Figure 1 illustrates that part of the mass flow sensor 1 projects into the main channel 2. The main flow direction of the medium which flows in the main channel is denoted by the arrow 3. This medium is generally air which, under certain circumstances may also contain particles in solid or liquid form, for example dust or water droplets. The mass flow sensor 1 has a housing 5 in which a bypass channel 7 is formed. The bypass channel 7 has an inlet section 9, a first bypass channel section 11 which is embodied perpendicularly with respect to the main flow direction, a second bypass channel section 13 which is embodied parallel to the main flow direction 3, and a third bypass channel section 15 which is again embodied perpendicularly with respect to the main flow direction. In addition, mass flow sensor elements 17, 19, which preferably comprise temperature dependent resistors which are preferably connected to one another in the form of a Wheatstone measuring bridge according to the principle of an anemometer, are arranged in the bypass channel. In addition, a temperature sensor 21 which is preferably embodied in tablet shape and is provided for sensing the temperature of the medium flowing in the main channel 2 is also preferably assigned to the mass flow sensor 1. In addition, a flow guiding channel 2 3 is mounted upstream of the mass flow sensor 1 and, in particular, the inlet section 9 of the bypass channel 7 in the main flow direction. The flow guiding channel 23 is embodied in such a way that its inlet cross section 25, which runs perpendicularly with respect to the main flow direction 3, has, with respect to its outlet cross section 27 which runs perpendicularly with respect to the main flow direction 23, a maximum overlap of a third with respect to the inlet cross section 23. The inlet cross section 25 is essentially arranged centrally in the main channel 2. The flow guiding channel 23 is embodied and arranged in such a way that said flow guiding channel 23 directs at least some of the medium flowing in it to the inlet section 9 of the mass flow sensor 1 and has at least one cutout 29 toward the main channel 1, via which cutout communication occurs with the main channel 1 by bypassing the bypass channel 7. In the exemplary embodiment in figure 1, the cutout is formed in the region of the outlet cross section 27. However, additionally or alternatively, one or more corresponding cutouts can also be provided upstream thereof in the wall of the flow guiding channel. The flow guiding channel 23 is secured in the main channel 2 by means of a fastener 35. The flow guiding channel 23 with its fastener 35 is preferably manufactured in one piece with the main channel 2 by injection molding. However, the fastener 35 can also be embodied as a separate part from the main channel 2. A cutout 37 (figure 3), medium flowing through which is directed to the temperature sensor element 21, is preferably provided in the fastener. The fastener preferably has a first web 39 and a second web 43. Figure 2 illustrates a longitudinal section perpendicularly to the sectional direction according to figure 1, with relevant areas being illustrated in several sectional planes which are characterized by A-A, B-B and C-C. The first web 39 is firstly embodied in the main flow direction as a very narrow web and is then widened downstream to form a shielding body 41. The shielding body 41 is preferably embodied in such a way that it shields part or a large part of the housing 5 of the mass flow sensor 1 from the flow in the main channel 2. The second web 43 of the fastener 35 preferably has the contour illustrated in figure 2 (see sectional plane C-C) . In this way, a particularly favorable flow divider property, which approximates a symmetrical embodiment of the first and second webs 39, 43, can be achieved by widening the second web 43 upstream in the main flow direction 3 compared to the first web 39. The flow guiding channel 23 is preferably embodied in an S shape. In addition, it is also apparent in figure 1 that the cross section of the flowing guiding channel 23 along the main flow direction 3 decreases in the flow direction of the medium within the flow guiding channel 23. However, the cross section can alternatively also remain the sane, for example. Guide contours by means of which particles, in particular water droplets or else oil droplets, which are separated off by centrifugal force separation are guided selectively along the wall, specifically toward at least one cutout 29 in the flow guiding channel 23, are preferably provided in the wall of the flow guiding channel and in this way these particles can be selectively kept away from the mass flow sensor elements 17, 19. Patent Claims 1. A mass flow sensor device for at least partial arrangement in a main channel (1) in which a mass flow flows in a main flow direction (3) , which mass flow sensor device has a mass flow sensor (1) with a bypass channel (7) which has an inlet section (9) via which mass flow can flow out of the main channel (2) into the bypass channel (7) and having at least one mass flow sensor element (17, 19) by means of which a variable which is characteristic of the mass flow in the main channel (2) can be sensed, wherein a flow guiding channel (23) is provided whose inlet cross section (25), which runs perpendicularly with respect to the main flow direction (3) , has, with its outlet cross section (27), which runs perpendicularly with respect to the main flow direction (3), a maximum overlap of a third with respect to the inlet cross section (25), and the inlet cross section (25) is arranged essentially centrally in the main channel (2), and the flow guiding channel (23) is embodied and arranged in such a way that said channel (23) directs at least some of the medium flowing in it to the inlet section (9) of the mass flow sensor (1) and has at least one cutout (29) toward the main channel (2), via which cutout (29) communication occurs with the main channel (2) by bypassing the bypass channel (7). 2. The mass flow sensor device as claimed in claim 1, in which the flow guiding channel (23) has a pipe longitudinal axis (33) which is tilted with respect to the main flow direction (3) . 3. The mass flow sensor device as claimed in one of the preceding claims, in which the flow guiding channel (23) is assigned a fastener (35) for securement in the main channel (2), which fastener (35) is embodied in such a way that it shields the mass flow sensor (1) from the flow in the main channel (2) in a region of the mass flow sensor (1) which is at the end side with respect to the main flow direction (3). 4. The mass flow sensor device as claimed in claim 3, in which the fastener (35) has a cutout (37), medium flowing through which is directed to a temperature sensor element (21) which is provided for sensing the temperature of the flowing medium in the mass flow sensor (1) . 5. The mass flow sensor device as claimed in one of claims 3 or 4, in which the section of the fastener (35) which has a shielding effect with respect to the end side region of the mass flow sensor (1) is embodied first, in the main flow direction (3), as a narrow web, and a non-shielding section of the fastener (35) is embodied so as to widen in relation to the narrow web, at least in part of the main flow direction (3) with respect to said narrow web. 6. A method as claimed in one of the preceding claims, in which the flow guiding channel (23) is embodied in an S shape. 7. The mass flow sensor device as claimed in one of the preceding claims, in which the flow guiding channel (23) is embodied in such a way that its cross section decreases in the flow direction. 8. The mass flow sensor device as claimed in one of the preceding claims, in which guide contours are provided in the wall of the flow guiding channel (23). 9. The mass flow sensor device as claimed in one of the preceding claims, in which the main channel and the flow guiding channel are embodied as a single injection molded component. A mass flow sensor device for at least a partial arrangement in a main channel (2) displays a mass flow sensor (1), in which a mass flow flows in the main direction of Flow. The mass flow sensor (1), which has a bypass channel (7) which displays an inlet section (9) can send current via the mass flow from the main channel (2) into the bypass channel (7). Furthermore, at leas st one mass flow sensing element (17,19) is proposed, by means of which a characteristic variable can be registered for the mass flow in the main channel (2). A flow guiding channel (23) is proposed which has an inlet cross section (25) running perpendicular to the main direction of flow (3) and which features a maximum one third overlap relative to the inlet cross section (25). The inlet cross section (25) is essentia lly arraanged in the middle of the main channel (2). The flow guid ding channel (23) is designed and arranged in such a way that it leads the flow medium at least partially to the inlet section (9) of the mass flow sensor (1), and has at least one passage (29) to the main channel (2) either outside the region of the overlap or in the region of the outlet cross section (27), by which communication with the main channel (2) occurs while bypassing the bypass channel (7).

Documents:

4644-KOLNP-2008-(20-06-2014)-ABSTRACT.pdf

4644-KOLNP-2008-(20-06-2014)-ANNEXURE TO FORM 3.pdf

4644-KOLNP-2008-(20-06-2014)-CLAIMS.pdf

4644-KOLNP-2008-(20-06-2014)-CORRESPONDENCE.pdf

4644-KOLNP-2008-(20-06-2014)-DESCRIPTION (COMPLETE).pdf

4644-KOLNP-2008-(20-06-2014)-FORM-1.pdf

4644-KOLNP-2008-(20-06-2014)-FORM-2.pdf

4644-KOLNP-2008-(20-06-2014)-OTHERS.pdf

4644-KOLNP-2008-(20-06-2014)-PETITION UNDER RULE 137.pdf

4644-kolnp-2008-abstract.pdf

4644-kolnp-2008-claims.pdf

4644-kolnp-2008-correspondence.pdf

4644-kolnp-2008-description (complete).pdf

4644-kolnp-2008-drawings.pdf

4644-kolnp-2008-form 1.pdf

4644-kolnp-2008-form 2.pdf

4644-kolnp-2008-form 3.pdf

4644-kolnp-2008-form 5.pdf

4644-kolnp-2008-form-18.pdf

4644-kolnp-2008-gpa.pdf

4644-kolnp-2008-international preliminary examination report.pdf

4644-kolnp-2008-international publication.pdf

4644-kolnp-2008-international search report.pdf

4644-kolnp-2008-pct priority document notification.pdf

4644-kolnp-2008-pct request form.pdf

4644-kolnp-2008-specification.pdf

4644-kolnp-2008-translated copy of priority document.pdf

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