Level indicator for a motor vehicle tank

Abstract

Method for adjusting a fill level indicator (10) of a tank (4) of a motor vehicle (1), wherein a control device (8) carries out a refueling check, in which a fill level signal (12) of a fill level sensor device (5) is received and the fill level indicator (10) is adjusted as a function of the fill level signal (12), characterized in that the control device (8) carries out the refueling check as a function of a detection signal (13) of a detection device (6), by which a predetermined tampering with a tank inlet (7) of the tank (4) is detected, wherein when the motor vehicle (1) starts moving, a value of the detection signal (13) determined while the motor vehicle (1) is at a standstill is compared with a current value of the detection signal (13), and it is thereby detected whether tampering is still present.

Description

[0001] The invention relates to a method for adjusting a fuel level indicator of a motor vehicle tank. The tank can be a fuel tank or a tank for another operating fluid of the motor vehicle. The invention also includes a display instrument by which the fuel level indicator can be displayed, as well as a motor vehicle with the display instrument according to the invention.

[0002] The level sensors installed in a motor vehicle for determining the tank content are subject to tolerances, and their accuracy can vary, for example, depending on the vehicle's inclination. A particularly critical situation is refueling a vehicle. This involves filling the tank with a fluid, such as fuel, which must then be reliably displayed on the display instrument. However, when the vehicle is stationary, the level indicated by the level sensors can change for another reason. For example, loading the vehicle can change its pitch and / or roll angle, thereby shifting the fluid in the tank. This can also result in a level signal that can be misinterpreted as a change in the amount of fluid.

[0003] From the generic document DE 10 2012 207 720 A1, a method for measuring and displaying a fuel level is known. After the ignition is switched on, a measured fuel level is displayed on a display device in the motor vehicle as the current fuel level at a first rate if a refueling event was also detected when the ignition was switched off. If no refueling event could be detected when the ignition was switched off, the measured fuel level is displayed as the current fuel level only at a second rate, which is slower than the first rate. As a result, a controller adjusts the fuel level displayed via the display device to the measured fuel level more quickly or more slowly, depending on the detection of a refueling event. This can prevent incorrect displays, which may be caused, for example, by the motor vehicle being parked on an incline.

[0004] US 2014 / 0196526 A1 describes a method for detecting a refueling process, in which a refueling event is detected via a refueling sensor. The refueling sensor can be a fill level sensor, a pressure sensor, a fuel filler flap switch, or the like.

[0005] DE 600 11 588 T2 describes a device for detecting the fuel supply to a fuel tank of a vehicle. Specifically, means are provided for detecting the starting status of the engine. Further means are provided for measuring the vehicle speed and for detecting the presence or absence of a fuel cap in a closed position. A first fuel level indicator can be displayed when the engine is switched off and a second fuel level indicator when the engine is switched on. A data processing unit can detect and display any fuel supply that has occurred.

[0006] DE 10 2008 039 796 A1 discloses a method for monitoring a fuel level in a motor vehicle tank, in which a baseline fuel level is established using a fuel level sensor when a refueling event is detected. A refueling event is detected when the fuel volume in the tank has increased while the vehicle is stationary. Fuel consumption is then tracked, and the amount of fuel remaining in the tank is calculated as a function of the fuel consumption and the baseline fuel level. A fuel gauge is controlled accordingly via a processor.

[0007] DE 10 2013 001 887 A1 discloses a tank detection device for detecting a refueling process in a vehicle. A change in the tank's fill level is only indicated when the vehicle is at a gas station and a float of a fill level gauge is located near an upper stop in the tank. It is also proposed to temporarily change a threshold value, above which a refueling process is concluded, to a lower value.

[0008] Finally, EP 1 184 241 A1 discloses a method for automatically controlling vehicle refueling processes using a credit card assigned to the vehicle. To prevent card misuse when refueling fleet vehicles, the vehicle's position is determined at the time of refueling and transmitted to a central location via remote data transmission. This allows the geographical position to be compared with the location where the credit card was used. Data transmission can be triggered by a fuel cap being operated or by a change in the fuel quantity in the tank when the vehicle is stationary.

[0009] The invention is based on the object of providing a method by which the driver is given an additional monitoring option during a refueling process.

[0010] The problem is solved by the subject matter of the independent patent claims. Advantageous developments of the invention are provided by the features of the dependent patent claims.

[0011] A method is provided for adjusting a fill level indicator of a liquid container or tank of a motor vehicle. The method is carried out in particular when the motor vehicle is stationary or after a stationary phase. The term “stationary phase” refers to a time interval or time range in which a driving speed of 0 km / h is detected. The ignition of the motor vehicle can be switched on or off. The engine of the motor vehicle can be switched on or off. The method ensures or checks whether a change in a fill level signal of a fill level sensor device was actually caused by a refueling process or by another event that did not lead to a change in the amount of operating fluid in the tank.The operating medium can be a fuel, for example gasoline or diesel or liquefied petroleum gas, or for example a lubricating oil or a coolant or a urea solution. In general, the operating medium is a liquid or a gas. In the method, a control device carries out a refueling test in which a fill level signal from a fill level sensor device is received and the fill level indicator is adjusted depending on the fill level signal. The fill level sensor device can be a device known per se from the prior art and can, for example, have a float. For this purpose, the control device can, for example, comprise a processor device or computing device of a display instrument of the motor vehicle or be designed as a separate control unit.

[0012] In order to check a change in the operating fluid quantity signaled by the fill level signal, the method additionally provides that the control device carries out the refueling test depending on a detection signal from a detection device. The detection device detects a predetermined manipulation of a tank inlet. In other words, a change or an event at the tank inlet must have been detected by the detection device, which is then also taken into account when adjusting the fill level indicator. For this purpose, the detection device can store the detection signal while the control device is switched off or in standby mode, so that the detection signal is available to the control device after it is switched on. The detection device can, for example,be provided on the basis of an electronic circuit for evaluating sensor signals.

[0013] This has the advantage that when adjusting the level indicator, it is taken into account that the amount of operating fluid can only have changed if there has been a predeterminable tampering with the tank inlet, i.e., if a corresponding tampering has occurred. For example, such tampering could consist of a fuel nozzle or nozzle being inserted into the tank inlet. Such an event, or such tampering with the tank inlet by inserting a nozzle, is a reliable indication that the amount of operating fluid in the tank has actually changed.

[0014] The invention also includes optional further developments whose features result in additional technical advantages.

[0015] A further development provides that the refueling check is activated depending on the detection signal from the detection device. In other words, the refueling check is only performed if the detection signal has actually signaled the predetermined tampering. Otherwise, the check is not performed at all. This has the advantage of preventing incorrect adjustment of a fill level indicator during and / or after a stationary phase. If the fill level signal from a fill level sensor device changes without the detection signal from the detection device signaling tampering with the tank inlet, adjustment of the fill level indicator can be excluded in this case.

[0016] According to a further development, the refueling test is carried out as follows. After the motor vehicle has come to a stop, a first tank level is determined at the beginning of the stationary phase. For example, the first tank level can be determined in a time interval of 5 to 20 seconds after the standstill is detected. The tank level is determined in particular using the fill level signal. A second tank level is then determined during the stationary phase or when driving off. In this case, the fill level signal is again used in particular. If the control device is switched on, the current tank level (second tank level) during the stationary phase can be continuously compared with the first tank level. If the control device is switched off or is in standby mode, this permanent fill level monitoring can be interrupted.The fill level indicator is only adjusted if the difference between the first and second tank levels is greater than a predetermined threshold value. The threshold value can, for example, be in a range of 2 liters to 5 liters. The advantage of this development is that a change in the fill level signal due, for example, to people getting in and changing the inclination of the vehicle, does not lead to an erroneous or incorrect adjustment of the fill level indicator. The threshold value can also be defined as fill level-dependent by being set by a characteristic curve. The sign of the difference between the tank levels can be used to distinguish whether operating fluid has been added or removed. In this context, a different threshold value or characteristic curve can be provided for each of these two cases, i.e. the threshold values ​​can be set as sign-dependent or direction-dependent.

[0017] In addition to determining the difference between the first and second tank levels, the determined difference can also be checked for plausibility. A further development provides that, if the difference is greater than the threshold value, the fill level indicator is only adjusted if the detection signal has also been received, i.e., if the detection signal signals the predetermined manipulation of the tank inlet. This advantageously makes it possible to avoid incorrect adjustment of the fill level indicator, which can occur when such a heavy load is loaded into or unloaded from the motor vehicle that the difference is determined to be greater than the threshold value due to a change in inclination. The causes mentioned are only examples.

[0018] According to a further development, the threshold value is lowered depending on the detection signal. In other words, the refueling check becomes more or more sensitive if the detection signal signals the predetermined manipulation of the tank inlet. When using a characteristic curve to determine a level-dependent threshold value, the characteristic curve can be modified. This has the advantage that the level indicator is correctly adjusted even when refueling or topping up small amounts of operating fluid.

[0019] To detect the predetermined manipulation, the detection device is provided in the manner described, by which the detection signal is generated.

[0020] According to a further development, the detection signal is generated by at least one sensor that senses a mechanical displacement of a flap and / or a slide and / or a fuel cap and / or a fuel tank closure. The sensor is in particular provided in each case by a button. This results in the advantage that the mechanical displacement is directly converted into an electrical signal. For example, the opening of a fuel cap can be detected by at least one sensor. The fuel cap can, for example, have a so-called push-push lock. Such a push-push lock is particularly suitable for generating the detection signal because a pin of the push-push lock is moved when the fuel cap is opened, which can be sensed particularly reliably.A redundant button can also be provided for error detection, so that tampering is detected or recognized using at least two buttons. If one of the two redundant buttons bounces and the other does not, this is an implausible detection result. A flap can, for example, be designed as a spring-loaded and pivoting cover of the tank inlet, so that vapors are retained in the tank and cannot evaporate from the tank inlet. Detecting a mechanical displacement, shift, or pivoting has the advantage that the detection signal is only generated when a mechanical force is exerted in the area of ​​the tank inlet. Thus, an operator does not have to perform the tampering intentionally or specifically. This makes it particularly reliable to distinguish between a refueling process and an accidental excitation or activation of the sensor (e.g., due to shaking the vehicle).For sensor plausibility checks or verification, the detection signal can be generated only if the sensor measures, detects, or signals tampering multiple times in succession. In particular, a threshold can be set for the number of positive detections. Furthermore, if a sensor does not signal tampering, e.g., a sensor signals a closed fuel cap, but the detection signal is still present, this sensor can be identified as defective.

[0021] According to a further development, the detection device generates the detection signal by means of at least one sensor, a change in the field strength of a magnetic and / or electric field. In particular, a Hall sensor and / or a capacitive proximity sensor is used. For example, the insertion of a fuel nozzle or a fuel pump nozzle into the tank inlet can be detected as tampering by means of a change in the field strength. It can be provided that a tank cap, for example a screw cap, has a magnet or a soft magnetic body, so that a change in the field strength results from removing the tank cap from the tank inlet. The detection of a change in the field strength has the advantage that the detection can be carried out without contact, thus avoiding the need for electrical voltages to be conducted in the area of ​​the tank inlet. This reduces the risk of fire, particularly with fuel.

[0022] According to a further development, the detection device generates a detection signal based on a change in the resistance of an electrical resistor by means of at least one electrical circuit. For example, a nozzle suspended or inserted into the tank inlet can be detected as an electrical bridging element between two electrical contacts arranged in the tank inlet. The electrical resistor can be an ohmic resistor, a capacitive resistor, or an inductive resistor. Capacitive resistors have the advantage that no current needs to be conducted in the area of ​​the tank inlet. The change in an ohmic resistor can be detected particularly reliably using a circuit that can be provided using simple means.

[0023] According to a further development, the detection signal is generated by the detection device using at least one photo sensor. The photo sensor can reliably detect whether a fuel cap and / or a fuel tank closure has been opened. This detection can be performed contactlessly and does not even require the insertion of a fuel nozzle. This allows reliable detection of tampering with the fuel inlet, particularly for tanks where a fuel nozzle does not require insertion (engine oil tank or coolant tank).

[0024] According to a further development, the detection signal is evaluated after the ignition or the control device is switched on, or after the control device previously operated in standby mode is activated. When the ignition is switched on, the display instrument, which has the display device for displaying the fill level indicator, is also switched on. By evaluating the detection signal, the current fill level is immediately displayed by the fill level indicator when the display instrument is switched on.

[0025] A further development uses the detection signal to trigger the evaluation of the fill level signal and / or the detection signal even when the ignition is off. In this development, a vehicle's communication bus and / or the display instrument are switched on or activated depending on the detection signal. This eliminates the need to temporarily store the detection signal until the ignition is switched on again. The communication bus can be a CAN bus (CAN controller area network), for example. In principle, however, any networking technology is suitable.

[0026] According to the invention, when the motor vehicle starts moving, a value of the detection signal determined while the vehicle was stationary is compared with a current value of the detection signal. This provides an additional monitoring option, as it can be determined whether the tampering is still present, for example, whether the fuel cap is still open. In this case, the driver can be warned.

[0027] The invention accordingly also includes a display instrument for a motor vehicle, which has a display device for displaying or representing a fill level indicator. Furthermore, the display instrument has a control device which is configured to adjust the fill level indicator according to an embodiment of the method according to the invention. The control device can be provided, for example, on the basis of a processor device or computing device, e.g. a microprocessor or a microcontroller. The display device can be formed, for example, by a mechanically pivotable fuel needle and / or a mechanically movable bar indicator and / or by a pixel-based screen and / or an LCD (liquid crystal display). The display instrument can be designed, for example, as an instrument cluster.The display instrument can also be made up of several individual components that can be distributed throughout the vehicle. For example, an instrument cluster can be combined with another control unit.

[0028] The invention also includes a motor vehicle. The motor vehicle according to the invention has an embodiment of the display instrument according to the invention. The display instrument is arranged, in particular, between a steering wheel and a windshield of the motor vehicle, where it can be viewed by the driver through the steering wheel while driving the motor vehicle. The motor vehicle according to the invention is preferably designed as a motorcycle, a motor vehicle, in particular as a passenger car or a truck.

[0029] An exemplary embodiment of the invention is described below. It shows: Fig. 1 a schematic representation of an embodiment of the motor vehicle according to the invention and Fig. 2 a flowchart of an embodiment of the method according to the invention.

[0030] The exemplary embodiment explained below is a preferred embodiment of the invention. In the exemplary embodiment, the described components of the embodiment each represent individual, independently considered features of the invention, which also further develop the invention independently of one another and are thus also to be considered as components of the invention, either individually or in a combination other than that shown. Furthermore, the described embodiment can also be supplemented by further features of the invention already described.

[0031] In the figures, functionally identical elements are provided with the same reference numerals.

[0032] Fig. Figure 1 shows a motor vehicle 1 and a fuel pump 2, through which the motor vehicle 1 is refueled or filled. The motor vehicle 1 can be a truck or a passenger car. In the example shown, the motor vehicle 1 is switched off and parked. In other words, the ignition of the motor vehicle 1 is switched off.

[0033] The motor vehicle 1 includes a display instrument 3, a tank 4, a fill level sensor 5, a detection device 6, and a tank inlet 7. Another term for tank inlet is also tank nozzle.

[0034] The display instrument 3 has a display device 9 and a control device 8. The display device 9 is designed to display a fill level indicator 10 of a fuel 11 in the tank 4. The fuel 11 can be, for example, a fuel for an internal combustion engine of the motor vehicle 1. The display device 9 can be an electromechanical display device with a pivotable pointer or a digital display device. It can be designed in a manner known per se from the prior art. The display device 9 can be controlled by the control device 8. For this purpose, the control device 8 can have a processor device, for example a microcontroller or a microprocessor.

[0035] The control device 8 can determine the fill level using the fill level sensor device 5. The fill level sensor device 5 generates a fill level signal 12 in a manner known per se. However, the fill level signal 12 can depend not only on the amount of operating fluid 11, but also on the arrangement of the operating fluid 11 in the tank 4. This arrangement can be changed, for example, by tilting the motor vehicle 1 due to a load or due to people boarding, or if the motor vehicle 1 is parked on a van or in a duplex garage and tilted using a loading ramp. The position of the motor vehicle 1 can also be changed in some other way while stationary. Thus, it is not clear to the control device 8 based on the fill level signal 12 alone whether the motor vehicle 1 has the same amount of operating fluid 11 in the tank 4 or whether additional operating fluid 11 was added via the fuel pump 2.

[0036] To check or verify the plausibility of a refueling process, the control device 8 uses the detection device 6. The detection device 6 generates a detection signal 13 depending on tampering with the tank inlet 7. The tank inlet 7 can have an inlet opening 14, a tank cap 15, and a tank closure 16. In the example shown, the motor vehicle 1 is actually being refueled. For this purpose, a nozzle 17 was inserted into the tank inlet 7. In order to insert the nozzle 17 into the tank inlet 7, the tank inlet 7 must be tampered with. Such tampering is detected by the detection device 6 and signaled by the detection signal 13. The detection device 6 can be designed to detect the opening of the tank cap 15. The removal of the tank closure 16 can be detected. The insertion and / or positioning of the nozzle 17 into the tank opening 14 can be detected.

[0037] To update, adjust, or adapt the fill level indicator 10 of the display device 9, the fill level signal 12 and the detection signal 13 are evaluated or analyzed by the control device 8. In other words, the fill level indicator 10 is adjusted depending on the fill level signal 12 and the detection signal 13.

[0038] For this purpose, the control device 8 can Fig. 2 Perform the procedures illustrated.

[0039] When the motor vehicle 1 stops, a driving speed of 0 km / h is detected, which signals the beginning of a stationary phase. In a step S1, a first tank fill level or fill level value F1 can be determined, for example, within a period of 5 seconds to 20 seconds after detecting the beginning of the stationary phase. During the stationary phase STAND, refueling of operating fluid 11 into the tank 4 is possible. If the control device 8 is switched off or operating in standby mode, this cannot be checked by the control device 8.

[0040] After restarting or starting the motor vehicle 1, for example, when the ignition is switched on, a second tank level or level value F2 can be determined in a step S2 based on the level signal 12. If the control device 8 remains switched on during the stationary phase, step S2 and the subsequent steps can be performed directly and repeatedly following step S1. In a step S3, a check is performed to determine whether the detection signal 13 indicates tampering with the tank inlet 7. Steps S2 and S3 can also be interchanged.

[0041] It can now be provided that only a plausibility check is carried out based on the detection signal 13. If the detection signal 13 does not signal any manipulation of the tank inlet 7 (in Fig. 2 represented by a minus sign “-”) the procedure can be ended (END).

[0042] In case of plausibility check and signaled manipulation (in Fig. 2 by a plus sign "+"), a difference 18 between the first tank level F1 and the second tank level F2 can be determined in a step S4. The difference 18 can be calculated as the difference between the two tank levels F1, F2. The difference 18 can, for example, be calculated in terms of amount, as shown in Fig. 2. A case distinction can also be made, where for F1<F2 ein Nachtanken und für F1> F2 a refueling or withdrawal is detected.

[0043] If the difference 18 is greater than a predetermined threshold value D (plus sign "+"), the fill level indicator 10 can be adjusted to the tank level F2 in a step S5 (UPDATE). If the difference 18 is smaller than the threshold value D, the method can be terminated. The method is also terminated after the update or adjustment of the fill level indicator 18. The threshold value D can be set based on the fill level using a characteristic curve. If a distinction is made between refueling and emptying, different threshold values ​​or characteristic curves can be provided for these two cases.

[0044] The new display value Aneu can be related to the absolute value F2 (Aneu = F2) or relative to the old display value Aalt by Aneu = Aalt + (F2 - F1).

[0045] As an alternative to the plausibility check, it can be provided in step S3 that the threshold value D is lowered if manipulation of the tank inlet 7 is signaled by the detection signal 13. Then, in step S4, the procedure can continue in the manner described on the basis of the lowered threshold value D.

[0046] In motor vehicle 1, this enables precise determination of the amount of fuel added and detection of the refueling process. The refueling process is detected or enhanced by using fuel cap / tank closure sensing and / or fuel pump nozzle insertion detection. A signal is sent when the tank cap is removed and / or the fuel pump flap is opened. The same applies when the fuel pump nozzle is inserted. In combination with existing refueling algorithms for adjusting the fill level indicator 10, the refueling system becomes more robust.

[0047] The detection system used can utilize sensors with fault detection, such as redundant sensors. The sensors can be installed directly on the components, enabling particularly robust detection. For example, a mechanical solution can be provided, with flaps or sliders that allow the sensor to be relocated. Sensing is also possible using magnets / field strength changes, buttons, and resistors. This solution requires little installation space and few components, making it advantageous for providing a cost-effective motor vehicle.

[0048] Overall, the example shows how the invention can detect refueling by sensing the tank cap, the tank flap, and the inserted nozzle.

Claims

[1] Method for adjusting a fill level indicator (10) of a tank (4) of a motor vehicle (1), wherein a control device (8) carries out a refuelling test, in which a fill level signal (12) of a fill level sensor device (5) is received and the fill level indicator (10) is adjusted depending on the fill level signal (12), characterized by that the control device (8) carries out the refueling test as a function of a detection signal (13) of a detection device (6), by means of which a predetermined manipulation of a tank inlet (7) of the tank (4) is detected, wherein when the motor vehicle (1) starts moving, a value of the detection signal (13) determined while the motor vehicle (1) is at a standstill is compared with a current value of the detection signal (13) and it is thereby detected whether manipulation is still present. [2] Method according to claim 1, wherein the refueling check is activated (S3) in dependence on the detection signal (13). [3] Method according to one of the preceding claims, wherein the refueling test comprises that after stopping at the beginning of a stationary phase of the motor vehicle (1), a first tank filling level (F1) is determined and then in or after the stationary phase a second tank filling level (F2) is determined (S1, S2) and the level indicator (10) is only adjusted if a difference (18) between the first and the second tank filling level (F1, F2) is greater than a predetermined threshold value (D) (S4). [4] Method according to claim 3, wherein in the event that the difference (18) is greater than the threshold value (D), the level indicator (10) is only adjusted if the detection signal (13) has additionally been received. [5] Method according to claim 3 or 4, wherein the threshold value (D) is lowered in dependence on the detection signal (13). [6] Method according to one of the preceding claims, wherein the detection signal (13) is generated by the detection device (6) by means of at least one sensor, namely a button, a mechanical displacement of a flap and / or a slide and / or a tank cap (15) and / or a tank closure (16). [7] Method according to one of the preceding claims, wherein the detection signal (13) is generated by the detection device (6) by means of at least one sensor, namely a Hall sensor and / or a capacitive proximity sensor, of a field strength change of a magnetic and / or electric field. [8] Method according to one of the preceding claims, wherein the detection signal (13) is generated by the detection device (6) by means of at least one electrical circuit by a change in the resistance of an electrical resistor. [9] Method according to one of the preceding claims, wherein the detection signal (13) is generated by the detection device (6) by means of at least one photosensor. [10] Method according to one of the preceding claims, wherein the detection signal (13) is evaluated after an ignition of the motor vehicle (1) is switched on. [11] Method according to one of the preceding claims, wherein a communication bus of the motor vehicle (1) and / or a display instrument (3) of the motor vehicle (1) is activated as a function of the detection signal (13). [12] Display instrument (3) for a motor vehicle (1) with a display device (9) for displaying a fill level indicator (10) and with a control device (8) which is designed to adjust the fill level indicator (10) according to a method according to one of the preceding claims. [13] Motor vehicle (1) with a display instrument (3) according to claim 12.

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