Air quality sensor and motor vehicle

Abstract

The invention relates to an air mass sensor for determining an air mass flow, having a housing (4) and a sensor electronics (6), wherein the sensor electronics is arranged at least partially in a housing chamber (8) of the housing (4), wherein the housing (4) has a flow channel (14) for guiding an air mass flow (L) to be measured through the housing (4), wherein the housing (4) has at least one compensation opening (26) in addition to an inlet opening (16) and an outlet opening (18) of the flow channel (14), which connects the flow channel (14) to the surroundings (U) of the housing (4).

Description

[0001] This invention relates to an air quality sensor for determining air mass flow, the air quality sensor having a housing and sensor electronics, wherein the sensor electronics are at least partially arranged in a housing chamber of the housing, and wherein the housing has a flow channel for guiding the air mass flow to be measured through the housing. Furthermore, the invention also relates to a motor vehicle having such an air quality sensor.

[0002] The type of air quality sensor mentioned at the beginning is known, for example, from documents US 8,763,452 B2 and DE102018219729 A1.

[0003] Such air quality sensors can be used, for example, to determine the air mass flow in the intake manifold of an internal combustion engine in a motor vehicle. Here, vibrational excitation may occur within the natural frequency range of the flow channel, which can adversely affect the measurement results. For example, an exhaust gas turbocharger may induce high-frequency pressure pulsations up to 20 kHz in the air mass flow to be measured. Therefore, for a specific excitation frequency or range, a significant deviation may occur between the measured air mass flow and the actual air mass flow. These deviations can adversely affect engine operation.

[0004] Against this backdrop, the technical problem upon which this invention is based is to describe an improved air quality sensor that is particularly robust to vibration excitation from an exhaust gas turbocharger. Furthermore, a motor vehicle equipped with such a sensor should also be described.

[0005] According to a first aspect, the present invention relates to an air quality sensor for determining air mass flow, the air quality sensor having a housing and sensor electronics, wherein the sensor electronics are at least partially arranged in a housing chamber of the housing, and wherein the housing has a flow channel for guiding the air mass flow to be measured through the housing. A key feature of the air quality sensor is that, in addition to the inlet and outlet openings of the flow channel, the housing has at least one compensation opening that connects the flow channel to the surrounding environment of the housing.

[0006] Therefore, the compensation opening establishes a fluid connection between the flow channel of the housing and the surrounding environment, allowing a portion of the air mass flow to be measured to flow from the flow channel into the surrounding environment of the housing to provide additional pressure compensation. In this way, the amplitude of vibration excitation caused by the high-frequency pressure pulsations of the turbocharger can be reduced, thereby enabling reliable measurement of the critical excitation frequency. In particular, this method can eliminate the natural frequency of the flow channel or mitigate the corresponding vibration response within one or more natural frequency ranges.

[0007] It can set exactly one compensation opening or two or more compensation openings.

[0008] The surrounding environment of the housing can be, in particular, the internal space of a pipe or conduit, in which the air quality sensor for determining the air mass flow is arranged.

[0009] The compensation opening can be a through hole cut into the wall of the shell, such as a drilled hole.

[0010] As an alternative or supplementary solution, the compensation opening can be formed between the housing components of the housing. As long as the housing has, for example, a first housing component and a second housing component assembled into the housing, the compensation opening can be a gap in the region of a seam or joint edge, in which the first and second housing components are form-fitted into and / or connected to each other.

[0011] The first housing component can be, for example, a cover or a shield. The second housing component can be the base of the housing, to which the cover is fixed.

[0012] The housing components can be connected to each other by means of an adhesive, wherein the compensation opening is at least partially adjacent to the adhesive that connects the housing components.

[0013] It can be specified that the compensation opening is part of an interrupted adhesive seam or an interrupted adhesive strip. Therefore, the compensation opening can be an interruption in an adhesive seam or adhesive strip that connects the housing components to each other. In particular, the adhesive seam or adhesive strip forms an adhesive connection of the housing components and further forms a seal of the flow channel relative to the surrounding environment, wherein the seal is partially interrupted to construct the compensation opening.

[0014] As an alternative or supplementary solution, a seal can be provided between the housing components, wherein the compensation opening is at least partially adjacent to the seal. The compensation opening can be cut into the seal, or the seal can be at least partially interrupted to form the compensation opening.

[0015] The flow channel can have a bypass or a bypass channel and a measurement channel, such that a portion of the air quality flow does not flow through the measurement channel to the measurement point of the air quality sensor, but branches into the bypass channel before the measurement point and is then led out of the housing.

[0016] The compensation opening can have a gap relative to the bypass channel.

[0017] The compensation opening can be arranged in the inlet region of the flow channel and, in particular, upstream of a branch of the flow channel, in the region of which the measurement channel and the bypass channel branch out.

[0018] As an alternative or supplementary solution, in addition to the discharge openings of the bypass channel and / or measuring channel, at least one compensation opening can be formed into the wall of the housing that defines the bypass channel and / or measuring channel. In this case, the compensation opening is arranged downstream of a branch of the flow pipe, branching off the measuring channel and bypass channel in the region of the branch.

[0019] "Downstream" means that the air mass flow overflows or flows through the relevant element later in time than the element arranged upstream. Therefore, the inlet opening of the measurement channel is arranged upstream of the measurement point, while the outlet opening of the measurement channel is arranged downstream of the measurement point.

[0020] The compensation opening can have a polygonal shape, particularly a rectangular or triangular shape. The compensation opening can also have a circular or elliptical shape. The compensation opening can be freely shaped.

[0021] In addition to measuring air mass flow, the air quality sensor can have supplementary functions. For example, besides measuring air mass flow, the air quality sensor can be configured to measure one or more of the following parameters: the pressure of the air mass flow; the humidity of the air mass flow; and the temperature of the air mass flow.

[0022] The measuring element of the sensor electronics of the air quality sensor can be a thermal measuring element, particularly a hot-film air quality measuring element. Such a hot-film air quality measuring element, for example, can have at least one heating element and two temperature sensors overflowing with an air mass flow, wherein the magnitude of the air mass flow can be derived from the different measured temperatures or temperature distributions of the temperature sensors. Such a hot-film air quality measuring element is described, for example, in DE 102018219729 A1.

[0023] It can be specified that the components of the sensor electronics arranged in the housing or electronic chamber of the air quality sensor are at least partially or completely encased in or wrapped in a casting material in order to protect the components of the sensor electronics from the influence of the surrounding environment.

[0024] It can be specified that a first wall element, which at least partially separates the bypass channel and the measurement channel, has a wall height that is at least partially reduced, allowing the first wall element to overflow at least partially, and / or has a through-hole allowing flow through the first wall element. As an alternative or supplementary embodiment, the air quality sensor is characterized in that a second wall element, which at least partially separates the inlet of the bypass channel and the flow channel, has a wall height that is at least partially reduced, allowing the second wall element to overflow at least partially, and / or the second wall element has a through-hole allowing flow through the second wall element.

[0025] Therefore, the reduced wall height and / or the through-hole enables additional fluid connectivity within the flow channel, providing additional pressure balance for the measurement channel. In this way, the amplitude of vibration excitation caused by the high-frequency pressure pulsations of the turbocharger can also be reduced, thereby enabling reliable measurement of the critical excitation frequency. In particular, this method can also eliminate the natural frequency of the flow channel or mitigate the corresponding vibration response within one or more natural frequency ranges.

[0026] It can be specified that the flow channel and the electronic device chamber are interconnected through an opening, wherein the electronic device chamber forms a pressure-balancing volume for the flow channel.

[0027] Therefore, the opening enables a fluid connection between the flow channel and the electronics compartment, allowing a portion of the air mass flow to be measured to flow from the flow channel into the electronics compartment. In this way, the amplitude of vibration excitation caused by the high-frequency pressure pulsations of the turbocharger can be reduced, thereby enabling reliable measurement of the critical excitation frequency. In particular, this method can also eliminate the natural frequency of the flow channel or mitigate the corresponding vibration response within one or more natural frequency ranges.

[0028] According to a second aspect, the present invention relates to a motor vehicle having an air quality sensor according to the invention.

[0029] The motor vehicle may have an internal combustion engine, wherein the air quality sensor is arranged in the intake manifold of the internal combustion engine to measure the air mass flow inside the intake manifold. The internal combustion engine may have one or more turbochargers.

[0030] The invention will now be described in detail with the aid of the accompanying drawings, which illustrate embodiments. The drawings are shown schematically as follows:

[0031] Figure 1 An air quality sensor according to the invention is shown in a perspective view from above;

[0032] Figure 2 Shown without any cover or cover Figure 1 Air quality sensor in the middle;

[0033] Figure 3 Another design of the air quality sensor according to the present invention is shown;

[0034] Figure 4 Another design of the air quality sensor according to the present invention is shown;

[0035] Figure 5 Another design of the air quality sensor according to the present invention is shown;

[0036] Figure 6 Another design of the air quality sensor according to the present invention is shown;

[0037] Figure 7 Another design of the air quality sensor according to the present invention is shown;

[0038] Figure 8 Another design of the air quality sensor according to the present invention is shown;

[0039] Figure 9 Another design of the air quality sensor according to the invention is shown without a cover or shield;

[0040] Figure 10 The enlarged diagram shows Figure 9 Air quality sensor in the middle;

[0041] Figure 11 A motor vehicle according to the invention is shown, having an air quality sensor according to the invention.

[0042] Figure 1 An air quality sensor 2 is shown for determining air mass flow.

[0043] The air quality sensor 2 has a housing 4. The air quality sensor 2 has a sensor electronics 6, wherein the sensor electronics 6 is arranged within a housing chamber or an electronics chamber 8 of the housing 4. Figure 2 To illustrate the electronics chamber 8 and the sensor electronics 6, in Figure 2 The cover 10, 12 or cover 10, 12 of the housing 4 are hidden.

[0044] The housing 4 has a flow channel 14 for guiding the air mass flow L to be measured through the housing 4.

[0045] The flow channel 14 has an inlet opening 16 for introducing the air mass flow L into the housing 4. The flow channel 14 has an outlet opening 18 for discharging the air mass flow L out of the housing 4. The flow channel 14 has a bypass 20 or a bypass channel 20 such that a portion of the air mass flow L does not flow to the measurement point 22 of the air quality sensor 2, but is branched off before the measurement point 22 and discharged from the housing 4 again.

[0046] The measuring element 24 of the sensor electronics 6 is arranged in the area of ​​measuring point 22. The measuring element 24 is a thermal measuring element 24, and more precisely, a thermal film air quality measuring element 24.

[0047] In addition to the inlet opening 16 and outlet opening 18 of the flow channel 14, the housing 4 also has a compensation opening 26 that connects the flow channel 14 to the surrounding environment U of the housing 4. In other words, there is a fluid connection between the surrounding environment U and the flow channel 14, allowing the air mass flow L to flow from the flow channel 14 into the surrounding environment U and vice versa.

[0048] The compensation opening 26 is a cylindrical through hole 26, which is cut into the wall 28 of the base 29 of the housing 4.

[0049] The compensation opening 26 is arranged in the region of the inlet 16 of the flow channel 14 and thus upstream of a branch of the flow channel 14, in the region of which the flow channel is branched into a measurement channel 30 and a bypass channel 20. Therefore, the compensation opening 26 is arranged separately from the bypass channel 20.

[0050] In addition, an additional compensation opening 32 is cut into the cover 12 of the housing 4, which connects the flow channel 14 to the surrounding environment U of the housing 4.

[0051] Here, the cover 12 is the first housing component 12 of the housing, the base 29 is the second housing component 29 of the housing 4, and the cover 10 is the third housing component 10 of the housing 4.

[0052] Figure 3 A top view shows the following according to Figure 2 Enlarged view of a section of the air quality sensor 2.

[0053] The mass flow L of air flowing into inlet 16 can partially escape through compensation opening 26. The same applies to compensation opening 32 (not shown) of cover 12.

[0054] Next, the flow channel 14 branches into the measurement channel 30 leading to the measurement point 24 and the bypass channel 20. The bypass channel bypasses the measurement point 24 and discharges a portion of the air mass flow L from the housing 4 without supplying it to the measurement point 24. The air mass flow L, which is supplied to the measurement point 24 through the measurement channel 30 and measured by the measurement element 24, is discharged from the housing 4 through the discharge opening 18 of the measurement channel 30.

[0055] Figure 4-8 Other embodiments of the air quality sensor 2 are shown, which differ from each other only in the design of the shape of their compensation opening 26.

[0056] Figure 4 An air quality sensor 2 with a narrow rectangular compensation opening 26 is shown, wherein the width B1 of the compensation opening 26 is less than one-third of the minimum width B2 of the flow channel 14 before the flow channel 14 branches into the measurement channel 30 and the bypass channel 20.

[0057] Figure 5 An air quality sensor 2 with two narrow rectangular compensation openings 26 is shown.

[0058] Figure 6 An air quality sensor 2 is shown with a wide rectangular compensation opening 26, wherein the width B3 of the compensation opening 26 is greater than one-third of the minimum width B2 of the flow channel 14 before the flow channel 14 branches into the measurement channel 30 and the bypass channel 20.

[0059] Figure 7 An air quality sensor 2 with a triangular compensation opening 26 is shown.

[0060] Figure 8 An air quality sensor 2 with a free-form compensation opening 26 is shown.

[0061] The selected shape of the compensation opening 26 can be determined in experiments and / or by means of simulation, and can be matched with the installation conditions and the excitation in the assembled state, thereby enabling reliable measurement of the critical excitation frequency. In particular, this method can reduce or eliminate the natural frequency of the flow channel.

[0062] It can be specified that a compensation opening 32 is cut out in the cover 12, the compensation opening being made according to... Figure 4-8 The compensation opening 26 is constructed.

[0063] Figure 9 and 10 Another design scheme for the air quality sensor 2 is shown, which is consistent with the design according to... Figure 1 The difference in the variant is that no bypass is provided and the compensation opening 26 is constructed as an interruption of the adhesive seam 34.

[0064] Figure 10 yes Figure 9 Enlarged image.

[0065] The adhesive seam 34 serves to connect the cover 12 to the housing 4 and seal the flow channel 14 relative to the surrounding environment U in the bonded area. In the area of ​​the compensation opening 26, the adhesive seam 34 shown on the left side of the figure is interrupted, so that a portion of the air mass flow L can escape between the cover 12 and the base 29 of the housing 4 through the compensation opening 26 when the cover 12 is installed.

[0066] Figure 11 A motor vehicle 100 is shown, which has a turbocharged internal combustion engine 110 and an air quality sensor 2, wherein the air quality sensor 2 is arranged in the intake manifold 120 of the internal combustion engine 110 to measure the air mass flow inside the intake manifold 120. The intake manifold 120 is connected to a turbocharged air cooler 130.

[0067] According to an alternative design of the present invention, the motor vehicle 100 can be a hybrid vehicle having at least one electric motor to supplement the internal combustion engine 110, the electric motor having a allocated traction battery.

Claims

1. An air quality sensor for determining air mass flow (2). -Has a housing (4), and - Equipped with sensor electronics (6). -The sensor electronics are at least partially arranged in the housing chamber (8) of the housing (4), -The housing (4) therein has a flow channel (14) for guiding the air mass flow (L) to be measured through the housing (4). Its features are, - In addition to the inlet opening (16) and outlet opening (18) of the flow channel (14), the housing (4) also has at least one compensation opening (26, 32), which connects the flow channel (14) to the surrounding environment (U) of the housing (4). - The compensation opening (26) is arranged in the area of ​​the inlet opening (16) of the flow channel (14) and is arranged upstream of the branch position where the flow channel (14) branches into the measurement channel (30) and the bypass channel (20).

2. The air quality sensor (2) according to claim 1. Its features are, - The compensation opening (26) is formed between the housing parts (12, 29) of the housing (4).

3. The air quality sensor (2) according to claim 2. Its features are, - The housing components (12, 29) are connected to each other by means of adhesive. - wherein the compensation opening (26) is at least partially adjacent to the adhesive that connects the housing parts (12, 29).

4. The air quality sensor (2) according to claim 3. Its features are, - The compensation opening (26) is part of the intermittent adhesive seam (34) or the intermittent adhesive strip.

5. The air quality sensor (2) according to any one of claims 2 to 4. Its features are, -A seal is provided between the housing components (12, 29). - wherein the compensation opening (26) is at least partially adjacent to the seal.

6. The air quality sensor (2) according to claim 5. Its features are, - The compensation opening (26) is cut into the seal, or the seal is at least partially interrupted in order to construct the compensation opening (26).

7. The air quality sensor (2) according to any one of claims 1 to 4. Its features are, - Two or more compensation openings (26) are provided.

8. The air quality sensor (2) according to any one of claims 1 to 4. Its features are, - The compensation opening (26) has a polygonal shape.

9. The air quality sensor (2) according to claim 8. Its features are, - The compensation opening (26) has a rectangular or triangular shape.

10. The air quality sensor (2) according to any one of claims 1 to 4. Its features are, - The compensation opening (26) has a circular or elliptical shape.

11. Motor vehicles Its features - Air quality sensor (2) according to any one of claims 1-10.

12. The motor vehicle according to claim 11, - Equipped with an internal combustion engine (110). Its features are, - The air quality sensor (2) is arranged in the intake manifold (120) of the internal combustion engine (110) for measuring the air mass flow inside the intake manifold (120).

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