Device for measuring a fill level, oil-lubricated engine and motor vehicle

Abstract

Device for measuring the fill level of a liquid in a container with an ultrasonic sensor, wherein the ultrasonic sensor is associated with a damping cup (1) with at least one pre-chamber (5), wherein at least one deflecting element (13, 14, 14', 14'', 14''') is arranged in the pre-chamber (5) which influences the flow of the liquid in the pre-chamber (5), wherein the deflecting element (13, 14, 14', 14'', 14''') has at least a first section and a second section having different widths, wherein the first section, which has a larger width, is arranged below the second section, which has a smaller width. characterized by that the antechamber (5) has two concentric rings (7, 8), and that in each concentric ring (7, 8) at least one of the deflection elements (13, 14, 14', 14'', 14'') is arranged.

Description

[0001] The invention relates to a device for measuring the fill level of a liquid in a container with an ultrasonic sensor, wherein the ultrasonic sensor is associated with a damping cup with at least one pre-chamber, wherein deflecting elements are arranged in the pre-chamber which influence the flow of the liquid in the pre-chamber.

[0002] The deflecting element has at least a first section and a second section which have different widths, wherein the first section, which has a larger width, is arranged below the second section, which has a smaller width.

[0003] A generic device for measuring a fill level is known from EP 2366984 B1.

[0004] These are primarily containers for holding engine oil. Ultrasonic sensors are predominantly used to determine the oil level in engines. These emit sound waves that are reflected at the interface between two media, in this case, gas and oil, and then received by the ultrasonic sensor. The measured travel time of the sound waves allows the fill level in the container holding the fluid to be determined. However, in a running engine, especially in a motor vehicle, the oil level is difficult or even impossible to determine because the oil is highly foamed, and the sound waves are reflected by the gas bubbles in the oil. The detected values ​​therefore vary considerably. To obtain a usable measurement, a clearly defined interface between the gas and the oil is required. To achieve this, so-called damping cups with a pre-chamber are used with the ultrasonic sensors.Within these damping cups, which enclose the measuring section of the ultrasonic sensor, the liquid to be measured is calmed and connected to the container only through a small opening in the damping cup. This small opening allows fewer gas bubbles to enter the damping cup. The liquid level in the damping cup corresponds to the liquid level outside the damping cup, but delays fluctuations caused, for example, by acceleration or cornering. In documents EP 2366984 B1 and WO 2008 / 009277 A1, pre-volumes or pre-chambers are also associated with the damping cup. These pre-volumes serve to degas the liquid to be measured, e.g., foamed oil, so that a relatively bubble-free liquid flows into the measuring section of the damping cup. Deflection elements are arranged in the pre-chamber to influence the flow of the liquid within it.This is intended to achieve a comparatively slow flow, so that the liquid remains in the pre-chamber for a comparatively long time and there is a possibility that the gas bubbles will escape.

[0005] Another device for determining the fill level of a medium is known from DE 10 2011 008 585 A1. Here, too, the device for measuring the fill level is associated with a pre-chamber. In the device, particularly in the pre-chamber, the medium is calmed and gas bubbles are expelled from the medium. The pre-chamber here has an annular shape in which deflection elements are arranged, the shape and size of which are uniform along the height of the pre-chamber.

[0006] The invention is based on the objective of creating a device of the type mentioned above that makes particularly good use of the available installation space and can therefore be manufactured in a particularly small size.

[0007] This problem is solved by a device having the features of claim 1. Advantageous further developments of the invention are described in the dependent claims.

[0008] In a device for measuring the fill level of a liquid in a container with an ultrasonic sensor, wherein the ultrasonic sensor is associated with a damping cup with at least one pre-chamber, and at least one deflecting element is arranged in the pre-chamber which influences the flow of the liquid in the pre-chamber, it is essential to the invention that the deflecting element has at least a first and a second section which have different widths, and that the first section, which has a larger width, is arranged below the second section, which has a smaller width.

[0009] The deflector is a component of a certain size positioned within the prechamber, around which the oil must flow on its way from the prechamber inlet to the outlet. The deflector alters the flow behavior of the fluid, particularly the oil, specifically by slowing its flow. At least a portion of the deflector, or a projection thereof, is perpendicular to the fluid flow direction, thus causing the change in the fluid's direction. The flow within the prechamber is greatest in the bottom region. This is primarily because the inlet for the oil into the prechamber and the outlet for the oil from the prechamber are typically located in a lower region of the prechamber, particularly in the bottom region.The invention, in which the deflector element has a greater width in its lower region than in its upper region, results in a greater reduction of the otherwise stronger flow in the lower region, thus achieving a more uniform slowing of the flow across the entire height of the prechamber. This inventive design of the deflector element allows for better utilization of the overall installation space, and the prechamber could therefore be built smaller while achieving the same results. The prechamber has an inlet. Preferably, the deflector element is widest in the inlet region. This is because the flow is typically strongest in the inlet region, and the width of the deflector element results in a particularly strong reduction of the flow there, thus achieving a more uniform distribution. Typically, the inlet is located in the bottom region, so the deflector element is preferably widest in this area.Overall, the device according to the invention creates a uniformly distributed flow velocity in the vertical direction. This results in a vertical interface between the different flow regions. In this way, the volume of the pre-chamber is optimally utilized.

[0010] Preferably, the area occupied by the deflecting element in the lower half of the prechamber is larger than the area occupied by the deflecting element in the upper half of the prechamber. This consideration includes the entire height of the prechamber. Particularly preferably, the width of the deflecting element changes continuously. This allows for a particularly pronounced uniformity of the flow velocity. In a preferred embodiment, the deflecting elements are formed directly adjacent to or connected to the side wall of the prechamber. The fluid must therefore flow around the deflecting element on one side, leaving a free space between the deflecting element and the opposite wall, to which the deflecting element is not connected.

[0011] In another preferred embodiment of the invention, the deflecting element is freestanding, i.e., it has no connection to the walls of the pre-chamber. In such a case, the fluid can flow around the deflecting elements on both sides. Particularly preferably, the deflecting elements are designed with an elliptical profile on the flow side, which narrows from bottom to top. For deflecting elements that are spaced apart from the wall, a deflecting element with an elliptical profile on both sides is preferred. Alternatively, the deflecting elements can also be designed as triangular deflecting elements. Due to their geometric design, these can also be described as ribs projecting into the flow. Parabolic or stepped deflecting elements can also be used as an alternative. However, the essential common feature is that the width of the deflecting elements decreases from bottom to top.

[0012] The width of the deflection elements is understood to be the area that extends perpendicular to the flow direction into the flow path of the prechamber, thereby causing a bypass. Preferably, the deflection elements extend over the entire height of the prechamber. This allows for a uniform flow distribution over the entire height of the prechamber. In an alternative preferred embodiment, the deflection element extends only over the lower 50% to 95%, preferably over the lower 60% to 90%, and most preferably over the lower 70% to 80% of the height of the prechamber. This is particularly advantageous if it is found that the flow in the lower part of the prechamber is so strong that a reduction in flow velocity in the upper part of the prechamber is no longer necessary.

[0013] In another preferred embodiment, the deflection elements also have a spatial extension in the direction of flow. The deflection elements can, for example, be pyramid-shaped. This is then a special embodiment of a two-dimensional triangular rib.

[0014] According to the invention, the prechamber comprises two prechambers arranged one behind the other in the flow direction, which are preferably configured as concentric chambers. In a preferred embodiment of the invention, the same number of deflection elements are arranged in the two prechambers. In particular, two or three deflection elements are preferably arranged in each prechamber. In a preferred embodiment, the deflection elements in the two prechambers are arranged in a mirror-symmetrical manner with respect to the wall separating the prechambers.

[0015] In a particularly preferred embodiment of the invention, the deflecting elements are arranged in the same circular segment enclosing less than 180°, and in particular in the same circular segment enclosing between 60° and 100°. In a particularly preferred embodiment, the inlet opening to the outer pre-chamber is arranged between the two deflecting elements thus arranged.

[0016] Furthermore, the invention relates to an engine, in particular a motor vehicle engine, or a motor vehicle, each characterized by having a device as described above.

[0017] The invention will now be explained in more detail with reference to a preferred embodiment shown in the drawing. Specifically, the schematic representations in: Fig. 1: a perspective view of a device according to the invention; Fig. 2: a sectional view of the device according to the invention Fig. 1; Fig. 3: a cross-section through the pre-volume of the device according to the invention; Fig. 4: a view of the pre-volume of the device according to the invention with walls shown transparently; Fig. 5: a view of an alternative deflection element; Fig. 6: a view of another alternative of a deflection element; and Fig. 7: A view of another alternative deflection element.

[0018] In Fig. Figure 1 shows a damping cup 1, which has a tube 2 in its upper section, inside which the measuring section runs, and a pre-volume 5 in its lower section. This lower section essentially consists of an outer wall 4, a lid 6, and a base. At the base of the measuring section 3, which is arranged in the tube 2, is an ultrasonic sensor that emits ultrasonic waves. These waves travel through the measuring section 3 and are reflected at the interface between the liquid to be measured, in particular oil, and the medium above it, in particular air, and then return to the ultrasonic sensor. The fill level can then be calculated from the transit time of the signal.

[0019] In Fig. Figure 2 shows a cross-section through the damping cup 1. The measuring section 3 runs inside the tube 2, at the bottom of which the ultrasonic sensor (not shown) is located. The pre-volume 5 consists of an inner ring 8 and an outer ring 7. These are formed by the outer wall 4 and an inner wall 9. In the view according to Fig. Figure 2 shows an inlet 10 for the entry of the liquid from the container into the pre-chamber 5. This inlet leads first into the outer ring 7. The inlet 10 is essentially a penetration through the outer wall 4. It is located near the bottom, in particular directly adjacent to the bottom of the damping cup 1. The liquid can then enter the inner ring 8 through an inlet 11 from the outer ring 7. The inlet 11 is offset from the inlet 10 by at least 90°, preferably, as shown here, by 180°. The liquid can then pass from the inner ring 8 through an inlet 12 into the measuring section 3. The inlet to the measuring section 3 is offset from the inlet 11 by at least 90°, but preferably, as shown here, by 180°.This arrangement of the inlets 10, 11 and 12 ensures that the liquid travels as long a path as possible in the antechamber 5, where it is calmed and degassed, so that there are as few air bubbles as possible in the liquid, which could reflect the ultrasound waves and thus interfere with the measurement result.

[0020] In Fig. Figure 3 shows a cross-section through the pre-chamber 5. Identical parts are marked with the same reference numerals. The pre-chamber 5 is essentially formed by the outer wall 4 and the inner wall 9, which here surround the tube 2 as concentric circles. The inlet 10 is located in the outer wall 4, through which the liquid from the container enters the damping cup, in particular the pre-volume 5 of the damping cup. The liquid then flows through the outer ring 7 to the inlet 11, which is arranged offset by 180° from the inlet 10. The liquid passes through the inlet 11 from the outer ring 7 into the inner ring 8. In the inner ring, the liquid flows to the inlet 12, through which the liquid passes from the inner ring 8 into the measuring section 3. To create a particularly favorable flow, two deflection elements 13 are arranged in the outer ring 7. Two deflection elements 14 are arranged in the inner ring 8.Each ring can contain one, two, three, or more deflection elements. In the illustrated embodiment, two deflection elements are arranged in each ring. Here, the deflection elements are each arranged adjacent to the inner wall 9, leaving a flow area on the outer side. The deflection elements 13, 14 in the inner ring 8 are arranged and configured as mirror images of the deflection elements 13 in the outer ring 7 with respect to the inner wall 9. The two deflection elements arranged in a ring are symmetrical to the inlet 10 and are positioned at an angle of 90° or less, preferably approximately 40° to 50°, to it.

[0021] In Fig. Figure 4 schematically depicts the pre-chamber 5 with transparent walls, making the deflection elements 13 and 14 particularly visible. These deflection elements are designed as ribs arranged as mirror images of each other. These ribs are perpendicular to the flow direction and influence the flow of the liquid. The deflection elements are widest at the bottom and narrower in an upper section, where the rib becomes continuously narrower. In particular, the outer contour of the rib is formed as part of an ellipse. Since gravity would otherwise cause the flow to primarily form in the bottom of the pre-chamber 5, the deflection elements, which are narrower at the top than at the bottom, ensure that the flow is evened out over the entire height of the pre-chamber 5, thus maximizing the utilization of its volume.The deflection elements 13, 14 preferably extend vertically over at least the lower 60% of the pre-volume, preferably over 70%, particularly 80%, and in some embodiments also over the entire height of the pre-volume 5. In the embodiment shown here, the deflection elements extend over approximately 90% of the height of the pre-volume. Two deflection elements 13 are arranged in the outer ring 7. These are arranged symmetrically with respect to the inlet 10 and the inlet 12.

[0022] In Fig. Figure 5 shows an alternative embodiment of a deflection element 14', which is arranged here in the inner ring 8. The outer contour of the deflection element 14' forms a straight line. At the bottom of the pre-volume 5, the deflection element 14' extends over two-thirds of the width and then over the entire height, tapering to approximately half the width of the inner ring 8.

[0023] In Fig. Figure 6 shows another variant of a deflection element 14'' in the inner ring 8. Here, the deflection element 14'' has the shape of a triangle and extends over two-thirds of its width in the lower region, tapering to almost zero at the upper end of the pre-chamber 5, so that the ring 8 is completely free of the deflection element 14'' at its upper end.

[0024] In Fig. Figure 7 shows another variant of a deflection element 14'''. This deflection element 14''' is smaller and narrower compared to deflection elements 14' and 14''. In the lower region, i.e., at the level of the inlets 10, 11, and 12, the deflection element 14''' occupies one-third of the width of the inner ring 8 and tapers upwards, ending at a height of approximately 80% of the height of the pre-chamber 5.

[0025] All the deflection elements 13, 14, 14', 14'' and 14''' shown have in common that they are wider in the lower area than in the upper area. In particular, the area covered and blocked off to the flow of liquid in the lower half is larger than the area blocked off in the upper half of the respective ring.

[0026] All features mentioned in the preceding description and in the claims can be combined in any selection with the features of the independent claim. The disclosure of the invention is therefore not limited to the described or claimed combinations of features; rather, all combinations of features meaningful within the scope of the invention are to be considered disclosed.

Claims

[1] Device for measuring a fill level of a liquid in a container with an ultrasonic sensor, wherein the ultrasonic sensor is assigned a damping cup (1) with at least one pre-chamber (5), wherein in the pre-chamber (5) at least one deflection element (13, 14, 14', 14'', 14''') is arranged, which influences a flow of the liquid in the pre-chamber (5), wherein the deflection element (13, 14, 14', 14'', 14''') has at least a first section and a second section, which have a different width, wherein the first section, which has a greater width, is arranged below the second section, which has a smaller width, characterized by , that the pre-chamber (5) has two concentric rings (7, 8), and that at least one of the deflection elements (13, 14, 14', 14'', 14''') is arranged in each concentric ring (7, 8). [2] Device according to claim 1, characterized bythat the width of the deflection element (13, 14, 14', 14'', 14''') changes continuously. [3] Device according to one of claims 1 or 2, characterized by that an area occupied by the deflection element (13, 14, 14', 14'', 14''') in the lower half of the pre-chamber (5) is larger than an area occupied by the deflection element (13, 14, 14', 14'', 14''') in the upper half of the pre-chamber (5). [4] Device according to one of the preceding claims, characterized by that the pre-chamber (5) has an inlet (10, 11) and that the width of the deflection element (13, 14, 14', 14'', 14''') is greatest in the region of the inlet (10, 11). [5] Device according to one of the preceding claims, characterized by that the deflection element (13, 14, 14', 14'', 14''') is free-standing, ie has no connection to a wall of the pre-chamber (5). [6] Device according to one of the preceding claims, characterized bythat the deflection element (13, 14, 14', 14'', 14''') has an elliptical profile which becomes narrower from bottom to top. [7] Device according to one of the preceding claims, characterized by that the deflection element (13, 14, 14', 14'', 14''') extends over the entire height of the pre-chamber (5). [8] Device according to one of the preceding claims, characterized by that the deflection element (13, 14, 14', 14'', 14''') has a triangular profile. [9] Device according to one of the preceding claims, characterized by that the deflection element (13, 14, 14', 14'', 14''') also has a spatial extension in the flow direction of the liquid flow. [10] Device according to one of the preceding claims, characterized by that the deflection elements (13, 14, 14', 14'', 14''') are arranged mirror-symmetrically to a wall (9) separating the concentric rings (7, 8). [11] Device according to one of the preceding claims, characterized by that the deflection element (13, 14, 14', 14'', 14''') extends over the lower 70% to 90% of the height of the prechamber. [12] Device according to one of the preceding claims, characterized by that the pre-chamber (5) has an inlet (10) into the pre-chamber (5) and that a deflection element (13, 14, 14', 14'', 14''') is arranged on both sides of the inlet (10) at the same distance. [13] Oil-lubricated engine, characterized by that the engine comprises a device according to one of the preceding claims. [14] Motor vehicle, characterized by that the motor vehicle has a device according to one of claims 1 to 12.

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