DE10201770A1 - Liquid or material level sensor, especially for motor vehicle use, comprises an optical sensor arrangement external to a material reservoir with a transparent wall section so that it is less sensitive to interference effects - Google Patents

Abstract

Filling level sensor for determining the amount of material (5) within a container (3). Sensor comprises a transmitter (1) for transmission of radiation and a receiver (2) for detecting said radiation. The beam path passes through any material between the two. The material acts to reflect or absorb the light, so that only minimal or no light is detected. Absence of material or liquid is indicated by detection of a light signal.

Description

The invention relates to a vehicle with at least one partially arranged outside a container Level sensor for determining a level of a Substance according to the preamble of claim 1.

In vehicles such as B. passenger cars or Commercial vehicles are mainly liquid supplies used. For example, fuels Brake fluids, oils and water-containing liquids especially for cooling the engine or the passenger compartment as well as for cleaning the vehicle windows or headlights used. The different operating materials are in appropriate containers stored and if necessary the each intended purpose supplied.

Appropriate vehicles or containers often have Level sensors on the z. B. reaching one certain level or falling below a level below a predetermined minimum threshold and the Signal the need to fill the container (see DE 694 27 057 T2 and DE 43 15 519 C2).

This already known level sensors in vehicles determine the level of the liquids, for example by means of a float. The swimmer is on among other things guided by a vertical guide and points if necessary a magnet on it, which is generally a reed switch when falling below or exceeding a predetermined Minimum fill level operated accordingly. This Level sensors are partly in the container or in contact with the water to be used. Movable parts are comparatively prone to failure. Chemically reactive Liquids or corresponding additives, among others, the Cooling or washing water can contact individual parts of the Level sensor affect what also Susceptibility to faults increased.

In contrast, the object of the invention is to provide a vehicle with one at least partially outside a container arranged level sensor for determining a Propose the level of a substance, the The level sensor's susceptibility to faults is significantly reduced becomes.

This task is based on a vehicle's type mentioned in the introduction, by the characteristic features of claim 1 solved.

By the measures mentioned in the subclaims advantageous embodiments and developments of the invention possible.

Accordingly, one according to the invention is distinguished Vending machine characterized in that the level sensor at least one transmitter for emitting radiation as well a receiver for receiving the emitted radiation having.

In a fill level sensor according to the invention, the Radiation from the transmitter advantageously at least partially through the inside of the container to the receiver. Is the Container with a liquid for radiation is as impermeable as possible, filled and located Fill level of the operating material above the sensor, so it hits the radiation on the operating fluid and is from this absorbed or reflected. As a result, the recipient receives preferably no or a relatively low radiation, thereby advantageously a corresponding signal is generated, the level by means of an evaluation unit or the presence of the substance signals. The Receiving or not receiving the radiation used accordingly for signaling.

The liquids to be detected in a vehicle such as Fuels, oils and those with colored additives mixed cooling or washing liquids are general largely impermeable to radiation.

The container advantageously comprises at least one for at least partially transmit the radiation Wall section. This allows the transmitter and / or the Receiver can be placed outside of the container, which an influence or impairment of the operating material can be largely prevented.

The wall section preferably comprises at least one for Beam direction oblique, especially at the Boundary surface arranged inside the container. With this you can Fill levels, on the one hand, more liquid or, if necessary, more solid Operating fluids are determined that the radiation absorb and / or reflect. On the other hand, in advantageously by means of the level sensor according to the Invention additionally the level or the presence of especially liquid, largely for radiation permeable consumables such. B. water or relative strongly diluted cooling or washing liquid is detected become. For example, the driver can cool and / or Dilute wash water with pure water to the extent that these become largely transparent to the radiation.

According to the invention, an optical refraction or Redirection of the beam path to the beam direction oblique interface due to the different Refractive index of air or the liquid allows.

It is advantageously provided that the Angle of incidence of the radiation with respect to the oblique angle Interface larger than that of the refractive indices of the media dependent critical angle of total reflection is.

Advantageously, according to the invention for Determining the fill levels of several containers independently on the state of matter and / or on the refractive indices of the Detecting substances several, almost identical Level sensors used in a single vehicle become. This leads in particular to comparatively high ones Production numbers of a correspondingly versatile Level sensor, so that the manufacturing cost compared to different, special level sensors with a relatively small number of pieces according to the prior art can significantly reduce.

In addition, the level sensor according to the invention completely outside the container, so that impairment of components of the sensor underneath partly due to chemically reactive cooling and / or No detergent. Moving parts are in to avoid completely advantageously.

In a special development of the invention, the oblique interface is the entrance surface of the radiation in the container. This results in an advantageous manner due to the between the interface and receiver located interior of the container a large distance between the radiation refractive interface and the Receiver, so that a comparatively small deflection of the Radiation at the interface, e.g. B. due to a relative small difference in the refractive indices of air and the liquid fuel, to a relatively large, cross-directional or lateral deviation in the Area of the recipient. In particular, this enables that the radiation is relative in an advantageous manner is directed far past the receiver. For example hereby achieved that due to the optical refraction of the Radiation as little as possible or none under certain circumstances existing scattered radiation is perceptible by the receiver.

The transmitter may be on one side of the container and the receiver on an opposite side Side of the container arranged. For example, transmitters or receiver plane-parallel on a container wall and / or be arranged at an angle to the container wall. The Wall section of the container can both according to the invention an almost constant wall thickness as well changing wall thickness in the entrance or exit area of radiation.

In a special variant of the invention, the Arrangement of the entry and exit surface of the A prism, a lens or an optical grating out.

The beam path advantageously runs through a intended form of the container, in particular Bulge, bulge or the like. Appropriate Formations are comparatively easy to produce.

If necessary, the shape is formed such that in Depending on the level of the substance to be detected The radiation is reflected or not reflected on it, so that the receiver receives the radiation or not receives. Here are the sender and the receiver optionally arranged side by side.

The formation may be designed in such a way that preferably standard components, such as. B. commercially available Transmitter, receiver or light barriers or the like, can be advantageously arranged on the formation. It it is conceivable that the beam path through one for this provided recess or cavity of the container wall runs.

The beam path preferably runs through a provided corner area of the container. Often point corresponding containers already have an essentially angular, in particular a square cross-section, so that the Level sensor according to the invention already without change existing container shapes can be arranged on them. This enables an economically advantageous implementation of the Invention. In addition, according to the invention Variant if necessary, an advantageous retrofit to already existing containers can be realized with little effort.

Advantageously, at least two sections of the Formation at an angle, in particular almost 90 degrees, arranged to each other. This is advantageous Dimensioning of radiation that can be crossed out Container interior possible.

In general, the entry and exit area of the Container as a coherent, for radiation at least partially permeable wall section or from at least two separate wall sections can be realized. The container is preferably essentially made of a the radiation is at least partially transparent material educated. In the latter training of Invention is a particularly flexible arrangement of the Level sensor can be implemented on the container.

In an advantageous variant of the invention, the Radiation a predetermined, relatively narrow Wavelength range. This will be more advantageous Way a defined refraction or deflection of the radiation achieved according to the invention.

The transmitter or receiver can, for example, transmit or Receiving radiation in the visible as well as in the ultraviolet wavelength range are formed. The receiver or the transmitter are advantageously used for Sending or receiving infrared radiation trained. A corresponding fill level sensor is advantageous Wise to interference from daylight comparatively insensitive. For example, the transmitter as an infrared diode and the receiver as a corresponding photo Transistor are formed. Preferably for the Sender and / or the receiver already commercially available Standard components used.

The transmitter can advantageously be used intermittently or are operated temporarily and / or clocked. hereby can cause interference from outside light as well as energy requirements be significantly reduced.

The beam path advantageously runs during the Measurement phase in an almost horizontal plane. This is an advantageous arrangement in the area of a largely vertical longitudinal edge of the container can be realized. For example, the level sensor is close to one vertical longitudinal groove and / or a corresponding corner area arranged of the container. Alternatively, the Beam path during the measurement phase in an almost vertical Level. In certain applications, the Corresponding sensor on the horizontal longitudinal edges of the container to be ordered.

Generally, a sensor can be switched on by means of a control unit Signal, especially for a user or consumer generates the non-existence of the substance or the Signals the presence of preferably air in the container, additionally in an advantageous manner in the absence generate a corresponding signal from the container. According to the Invention can be a level sensor for determining the Level of a substance in the container and in addition to Determined the presence of the container become. In general, the level sensor is for this to be placed completely outside the container. This Variants of the invention are primarily for interchangeable Container to use.

In a special development of the invention Evaluation unit for the quantitative evaluation of the Receiver detected radiation or amount of radiation intended. This can be used in an advantageous manner Contamination of the container and / or a quantitative one Determines the parameters of the substance and if necessary be signaled. For example, the need to cleaning the container are displayed advantageously.

In an advantageous variant of the invention, the transmitter and the receiver in parallel in the same circuit with two Connections switched, one controlled by the receiver Electronic component is provided, which is the voltage and / or the current between the two connections affected. With such a circuit arrangement fill level sensor according to the invention, the number of necessary connections to the corresponding control unit reduce two connections, reducing the wiring effort both in terms of material and assembly is reduced.

There is generally an enormous amount in the automotive industry Cost pressure, so that the connection and wiring the sensor represents a not inconsiderable effort. Often these are devices with large numbers, so that even small savings with the help of this variant the invention noticeably contribute to cost reduction.

The measurement signal can be that in the energized state of the sensor voltage present between the connections or in Circuit flowing current can be evaluated. The recipient such a sensor arrangement can be, for example Resistance dependent on the measured variable, a dependent on the measured variable Capacitance and / or an inductance dependent on the measured variable his.

In a further advantageous embodiment, a Control device provided that works in cyclical operation. On the one hand, this allows the total electricity demand Sensor device including control unit clearly lower, resulting in a lower performance and thus more economical energy supply is feasible.

In addition, the use of several is in one cycle Sensors with circuit according to the invention by the same Control unit possible by alternating the individual sensors be queried for the state of their transmission link. In a special embodiment, a So-called multiplexer between the control unit and the various sensors arranged.

In conjunction with one of the above Embodiments in which a capacitor in Receiver circuit is arranged, is also in cycle mode particularly simple voltage evaluation possible by the Voltage curve at the two connections after termination a voltage or current pulse through the control unit is recorded and evaluated. Depending on the state of charge Capacity results in a different time course of this Tension.

Furthermore, the cycle operation results in a permanent one Resetting the sensor circuit to its initial state, see above that gain effects or oscillations caused by the Influencing the transmitter power through the parallel in receiver located in the same circuit, cannot have any adverse effects.

An embodiment of the invention is in the drawing shown and will be explained in more detail below with reference to the figures explained.

In detail shows:

Fig. 1 is a schematic plan view of a sensor assembly according to the invention with a level below the sensor,

Fig. 2 is a schematic plan view of the sensor assembly with a level of liquid above the sensor,

Fig. 3 is a schematic plan view of a section of a container wall with a thickened portion,

Fig. 4 is a schematic top view of another sensor arrangement according to the invention with a level below the sensor,

Fig. 5 is a schematic plan view of the sensor assembly of FIG. 4 with a level of liquid above the sensor,

Fig. 6 shows a schematic plan view of a third sensor arrangement according to the invention in a corner region of a container with a level below the sensor and

Fig. 7 is a schematic plan view of a fourth, inventive sensor arrangement with a level below the sensor.

In Fig. 1, a level sensor with a transmitter 1 and a receiver 2 is arranged on a container 3 . The transmitter 1 is designed in particular as an IR diode, so that it emits IR radiation 4 , which can be detected by the receiver 2 , which is designed as a corresponding phototransistor.

The container 3 is made according to FIG. 1 essentially from a material that is largely transparent to the IR radiation 4 , for. B. by means of injection molding, deep-drawing or comparable processes. The material of the container 3 has a refractive index n> 1, so that the radiation 4 is optically refracted on the outer and on the inner surfaces of the container 3 and the radiation 4 inside the container 3 is offset somewhat parallel to the outside of the container 3 extending radiation 4 .

When using a container material with a refractive index n of approximately 1, the radiation 4 according to FIG. 4 runs almost straight from the transmitter 1 through the wall of the container 3 and through its interior to the receiver 2 .

A “lightning” symbol each represents the detection of radiation 4 by the receiver 2 . According to the top view of FIGS. 1 and 4, there is a fill level of a fuel, not shown, below the sensor arrangement, so that the container interior between the transmitter 1 and the receiver 2 is preferably filled with air. In this case, for example, the fill level sensor generates an electrical or optical and / or acoustic signal, which may be perceived by a user or service personnel and / or an almost automatic filling device of the container 3 . This accordingly makes it clear that the operating fluid in the container 3 has to be refilled.

To determine a predetermined maximum fill level, a fill level sensor according to the invention can be arranged in the upper region of the container 3 . For example, a corresponding evaluation unit is designed such that, in the event that the receiver 2 of the sensor receives the radiation 4 , it does not generate an electrical or optical and / or acoustic warning signal for the driver.

In FIGS. 2 and 5 the situation is shown in which a liquid 5, z. B. fuel, lubricating oil, brake fluid, refrigerant of an air conditioning system, almost pure water or a washing or cooling water mixture, in particular mixed with an antifreeze, is present at least up to the level of the almost horizontally arranged level sensor in the container 3 . The partial reflection or absorption of the radiation 4 by corresponding liquids 5 or operating materials is not shown in any more detail in these figures.

The liquid 5 according to FIG. 2 has a refractive index n which is not equal to the refractive index of air and almost the same as the refractive index of the container material, so that the radiation 4, for example at an interface 6 at an angle to the beam direction and arranged on the outside of the container. B. is optically broken in the manner shown in FIG. 2. As a result, the radiation 4 is deflected such that it cannot be received by the receiver 2 . The presence of the operating material or the liquid 5 between the transmitter 1 and the receiver 2 can be detected accordingly, which generally signals to the driver that the container 3 is sufficiently filled with the operating material or the liquid 5 .

The level sensor shown works on the principle of optical refraction, so that almost transparent or radiation-permeable liquids 5 can be detected. In addition, operating fluids absorbing or reflecting radiation 4 can also be detected with the aid of a fill level sensor according to the invention. In the case of appropriately designed liquids 5 , both the optical refraction and the optical absorption or reflection of the radiation 4 can be used to determine the fill level.

The liquid 5 according to FIG. 5 has a refractive index n which is not equal to the refractive indices of air or of the container material, so that in this case the radiation 4, for example, at an interface 6 arranged at an angle to the beam direction on the inside of the container. B. is optically broken in the manner shown in FIG. 4. As a result, the radiation 4 is again deflected in such a way that it cannot be received by the receiver 2 . The presence of the operating material or the liquid 5 is again detected accordingly.

Furthermore, in particular for exhaust gas treatment, fill levels of solids such as powders, pastes, pellets, tablets or the like can also be detected as the fuel for the vehicle according to the invention. Operating fluids of this type are generally detected on the basis of the optical absorption and / or reflection of the radiation 4 . In addition, it is conceivable according to the invention to also detect gaseous operating materials or decomposition products of operating materials for exhaust gas treatment, in particular for denitrification of exhaust gas, with a different refractive index with respect to air.

In FIG. 6, a further level sensor assembly is shown according to the invention, the transmitter 1 and the receiver is disposed at a corner portion of the container 3 2. This represents a variant of the invention that is particularly easy to implement, since the interface 6 , which is to be provided in particular for optical refraction and is arranged at an angle to the beam direction, is realized by means of an advantageous arrangement of the transmitter 1 or receiver 2 . This variant can be used, among other things, for retrofitting existing, generally angular containers 3 .

By way of example in FIGS. 1, 2, 4 to 6 shown a nearly rectangular protrusion 8, so that the oblique angle is arranged for radiation 4 interface 6 in a particularly simple manner is implemented. In Fig. 7 a further level sensor assembly is shown in accordance with the invention. Here, the bulge 8 has a wall 9 arranged at an angle to the beam direction with the interface 6 and a wall 10 arranged almost perpendicular to the beam direction. Fig. 7 shows the case is that the level of the operating fluid is below the sensor assembly such that the radiation 4 is received by the receiver 2. With regard to this fill level sensor arrangement, the situation that the fill level of the operating material 5 is above the sensor arrangement is comparable to FIGS. 2 and 5.

In Fig. 3a, a section of a container wall with a thickened portion 11 with the to the beam direction (indicated by double arrow P) oblique boundary surface 6 is shown in each b. Here, FIG 3a and 3b shows by way of example. Two different Strahleinfalls- or beam loss variants. The thickening 11 may be designed as a separate element arranged on an almost plane-parallel wall of the container 3 .

In addition to the embodiments of the invention shown in FIGS. 1 to 7, the transmitter 1 and the receiver 2 being arranged on an almost horizontal plane, an arrangement which is oblique or almost vertical with respect to the horizontal plane can alternatively also be implemented.

In addition, in particular in the case of comparatively large containers 3, it is possible to use a plurality of fill level sensors, preferably arranged one above the other, for detecting different fill levels of the fuel 5 .

The fill level sensor or the transmitter 1 and the receiver 2 are preferably arranged completely outside the container 3 , so that a comparatively simple assembly or repair of the fill level sensor can be realized and possible impairment due to chemically reactive operating materials 5 or additives is effectively prevented.

In special applications, the receiver 2 in particular can alternatively be arranged inside the container 3 .

Furthermore, an extension of the beam path by means of a reflector, in particular arranged outside the container, for deflecting the radiation 4 can be advantageous. Since this allows the deviation of the optically refracted from the non-refracted radiation 4 in the region of the receiver 2 to be significantly increased, the sensitivity of the fill level sensor according to the invention is decisively improved.

To determine the fill level of liquids 5 based on the optical refraction, the fill level sensor can in principle also be designed such that the receiver 2 receives the radiation 4 optically refracted by means of the liquid 5 . In particular, the interface 6 is advantageously to be aligned here. In this variant according to the invention, the receiver 2 cannot receive the unbroken radiation 4 .

Furthermore, it is conceivable that, due to the dependence of the refractive index n on qualitative material parameters of liquids 5, the fill level sensor can optionally also be designed as a sensor for determining a specific target material parameter of the operating material 5 . In the above variant, in which the receiver 2 receives the refracted radiation 4, the receiver 2 can only when a certain predetermined possible refractive index n receive the radiation 4 of the operating material or the liquid. 5

Advantageously, the receiver can 2, the radiation 4 at a given target material parameters received, at a deviation of the actual fuel parameter from the target material parameters the radiation 4 due to varying degrees of optical refraction or deflection of the radiation 4 is deflected past the receiver. 2

If necessary, in particular two level sensors, one for detecting the level of the operating material 5 and another for detecting the material parameter of the operating material 5 , can be provided. In a particularly structurally simple variant, a sensor according to the invention has, for example, a transmitter 1 and at least two receivers 2 , preferably one of the receivers 2 receiving the non-refracted radiation 4 and another receiver 2 receiving the predetermined substance parameters of the dissolved substance receives optically refracted radiation 4 corresponding to liquid 5 . If the actual substance parameter deviates from the target substance parameter of the dissolved substance in the liquid 5 , neither of the two receivers 2 generally receives the radiation 4 . In order to determine the most varied qualities of the substance parameter of the dissolved substance in the liquid 5 , additional, further receivers 2 can optionally be arranged on the container 3 along the spanned refractive plane. List of Reference Numerals 1 Transmitter
2 receivers
3 containers
4 radiation
5 liquid
6 interface
8 bulge
9 wall
10 wall
P arrow

Claims (16)

1. Vehicle with an at least partially outside a container ( 3 ) arranged level sensor for determining a level of a substance ( 5 ), characterized in that the level sensor at least one transmitter ( 1 ) for emitting radiation ( 4 ) and a receiver ( 2 ) for receiving the emitted radiation ( 4 ). 2. Vehicle according to claim 1, characterized in that the container ( 3 ) comprises at least one wall section ( 9 , 10 ) which is at least partially permeable to the radiation ( 4 ). 3. Vehicle according to one of the preceding claims, characterized in that the wall section comprises at least one boundary surface ( 6 ) oblique to the beam direction. 4. Vehicle according to one of the preceding claims, characterized in that the oblique-angled interface ( 6 ) forms the entry surface of the radiation ( 4 ) into the container ( 3 ). 5. Vehicle according to one of the preceding claims, characterized in that the beam path runs through a shape ( 8 ) of the container ( 3 ) provided for this purpose. 6. Vehicle according to one of the preceding claims, characterized in that the beam path runs through a corner region of the container ( 3 ) provided for this purpose. 7. Vehicle according to one of the preceding claims, characterized in that at least two sections ( 9 , 10 ) of the formation ( 8 ) are arranged at an angle to one another. 8. Vehicle according to one of the preceding claims, characterized in that the angle of the two sections ( 9 , 10 ) is almost 90 °. 9. Vehicle according to one of the preceding claims, characterized in that the transmitter ( 1 ) or the receiver ( 2 ) are designed to emit or receive infrared radiation ( 4 ). 10. Vehicle according to one of the preceding claims, characterized in that the transmitter ( 1 ) and the receiver ( 2 ) are connected in parallel in the same circuit between only two connections, wherein an electronic component controlled by the receiver ( 2 ) is provided, which the Voltage and / or the current between the connections influenced. 11. Vehicle according to one of the preceding claims, characterized in that the receiver ( 2 ) is designed as a measurement-dependent resistance, measurement-dependent capacitance and / or measurement-dependent inductance. 12. Vehicle according to one of the preceding claims, characterized characterized in that a control device is provided which a voltmeter connected between the connections having. 13. Vehicle according to one of the preceding claims, characterized characterized that the control unit for a cyclical operation is trained. 14. Vehicle according to one of the preceding claims, characterized characterized that a multiplexer for the operation of several Sensors with the same control unit is provided. 15. Washing device of a vehicle with an at least partially outside a container ( 3 ) arranged level sensor for determining a level of a washing liquid ( 5 ) for cleaning a vehicle window and / or lighting device, characterized in that the level sensor and / or the container ( 3 ) according one of the preceding claims is formed. 16. Cooling device for cooling a combustion device and / or a passenger compartment of a vehicle with a fill level sensor arranged at least partially outside a container ( 3 ) for determining a fill level of a cooling liquid ( 5 ), characterized in that the fill level sensor and / or the container ( 3 ) is formed according to one of the preceding claims.