GB2521320A

GB2521320A - Method and system for determining the quantity of a fluid, in particular fuel, in a tank

Info

Publication number: GB2521320A
Application number: GB1506698.8A
Authority: GB
Inventors: Venugopal Reddi; Harish Viswanathan
Original assignee: Daimler AG
Current assignee: Mercedes Benz Group AG
Priority date: 2015-04-21
Filing date: 2015-04-21
Publication date: 2015-06-17
Also published as: GB201506698D0

Abstract

The invention relates to a method and a system for determining the quantity of a fluid, in particular fuel, in a tank 12, the method comprising: by means of a sensor device 43, detecting at least one first amount of fluid entering the tank 12; and by means of the sensor device 43, detecting at least one second amount of fluid leaving the tank 12; wherein the quantity of the fluid is determined on the basis of the detected first and second amounts by means of a processing unit 50.

Description

Method and System for Determining the Quantity of a Fluid, in particular Fuel, in a Tank The invention relates to a method and a system for determining the quantity of a fluid, in particular fuel, in a tank.

ER 2 466 278 Al shows a method for estimating the fuel level in a vehicle tank, the method comprising measuring the fuel level through a fuel level sensor and acquiring information regarding the instantaneous fuel consumption available in the motor vehicle.

The method further comprises comparing said fuel level measurement with said information regarding the instantaneous consumption to estimate the fuel level in the tank.

Moreover, US 7 530 269 B2 shows a fuel level sensor for sensing and monitoring the level of remaining fluid in a container such as a fuel tank for a motorized vehicle. The fuel level sensor incorporates a float and pivot arm member attached to a hub that rotates about a pivot base.

In conventional methods and systems the quantity of a fluid such as fuel in a tank of a motor vehicle is determined indirectly by measuring the level of the fuel in the tank and indicating roughly the percentage of the fuel in the tank.

It is therefore an object of the present invention to provide a method and a system for determining the quantity of a fluid in a tank by means of which method and system the quantity can be determined particularly precisely.

This object is solved by a method having the features of patent claim 1 as well as a system having the features of patent claim 4. Advantageous embodiments with expedient developments of the invention are indicated in the other patent claims.

A first aspect of the present invention relates to a method for determining the quantity of a fluid in a tank. In particular, the method serves to determine the quantity of a fuel, in particular liquid fuel, in a fuel tank of a motor vehicle. In a first step of the method according to the present invention at least one first amount of fluid entering the tank is detected by means of a sensor device. In a second step of the method at least one second amount of fluid leaving the tank is detected by means of the sensor device. In a third step the quantity of the fluid is determined on the basis of the first and second amounts by means of a processing unit. By means of the method according to the present invention the volume of the fluid, in particular fuel, in the tank can be measured directly to a high degree of precision and any given instance in time so that the detected quantity of the fuel can be displayed, for example, in the interior of the motor vehicle. The idea behind the present invention is to directly measure the quantity and, thus, the mass of fluid entering the tank as well as the quantity and, thus, for example, the mass of fluid leaving the tank. By considering a residual amount of fluid in the tank the quantity of the fluid, in particular the volume of the fluid, in the tank can be calculated directly on the basis of the residual amount, the amount entering the tank and the amount leaving the tank.

For example, the respective amount is detected by at least one respective sensor configured to detect at least one parameter indicative of a mass flow of the fluid. For example, the respective sensor is configured as a pressure sensor by means of which the respective mass flow can be measured.

The measurement of the quantity in the tank is direct. Hence, a high accuracy is guaranteed. Moreover, moving parts can be avoided so that slosh effects do not contribute to loss of accuracy in the tank when the motor vehicle is moving. The method according to the present invention is easy to implement, wherein the quantity in the tank can be determined in a cost-effective way. Moreover, phase changes have no influence on the method so that the quantity of fluid in the tank can be determined particularly precisely. Moreover, the method according to the present invention and, thus, the measurement of the quantity in the tank does not depend on any complex shape of the tank. This means the geometry and the complexity of the tank does not effect the measurement so that the quantity of fluid in the tank can be determined particularly precisely even when the tank's geometry is very complex.

A second aspect of the invention relates to a system for determining the quantity of a fluid in a tank. In particular, the system is configured to determine the quantity of fuel in a tank of a motor vehicle. The system according to the present invention comprises a sensor device configured to detect at least one first amount of fuel entering the tank. Moreover, the sensor device is configured to detect at least one second amount of fuel leaving the tank. The system further comprises a processing unit configured to determine the quantity of the fluid on the basis of the detected first and second amounts. Advantages and advantageous embodiments of the method according to the present invention are to be regarded as advantages and advantageous embodiments of the system according to the present invention and vice versa.

Further advantages, features, and details of the invention derive from the following description of a preferred embodiment as well as from the drawing. The features and feature combinations previously mentioned in the description as well as the features and feature combinations mentioned in the following description of the figures and/or shown in the figures alone can be employed not only in the respectively indicated combination but also in other combination or taken alone without leaving the scope of the invention.

The drawing shows in: Fig. 1 a schematic sectional view of a system for determining the quantity of fuel in a tank of a motor vehicle, by means of which system the quantity of fuel can be determined directly and particularly precisely; and Fig. 2 a flow diagram illustrating a method for determining the quantity of fuel in the tank.

In the figures the same elements or elements having the same function are indicated by the same reference signs.

Fig. 1 shows a system 10 for determining the quantity of a fluid in a tank 12 of a motor vehicle. Said fluid is liquid fuel, wherein the tank 12 is a container in which said liquid fuel is contained. The tank 12 comprises a primary chamber 14 and a secondary chamber 16 configured to receive the fuel.

The motor vehicle comprises an internal combustion engine configured to be powered by the fuel contained in the tank 12. In order to supply the internal combustion engine with the fuel contained in the tank 12 the motor vehicle comprises a fuel supply system having a fuel pump 18 and jet pumps 20 and 22 configured to pump the fuel from the tank 12 to the internal combustion engine. The fuel supply system further comprises filters 24, 26 and 28 configured to filter the fuel which is pumped to the internal combustion engine. For example, the filter 26 is configured as a coarse filter. The fuel pumped from the tank 12 to the internal combustion engine is guided by means of lines 30 and 32, wherein the flow of the fuel to the internal combustion engine is illustrated by directional arrows 34.

The motor vehicle further comprises a tiller pipe 36 bounding a duct 38 which opens into the primary chamber 14. Thus, the tank 12 can be refueled by means of the filler pipe 36, in particular the duct 38. Moreover, the fuel supply system comprises a return line 40 via which fuel can be guided from the internal combustion engine back into the tank 12. The fuel flowing through the return line 40 into the tank 12 is illustrated by directional arrows 42. Hence, a first amount of fuel can enter the tank 12 via the filler pipe 36. Moreover, a second amount of fuel can leave the tank 12 via the lines 30 and 32, said second amount being pumped by the fuel supply system from the tank 12 to the internal combustion engine. Furthermore, a third amount of fuel can enter the tank 12 via the return line 40.

Moreover, a fourth amount of fuel can be contained in the tank 12, said fourth amount being also referred to as residual fuel.

In order to determine the quantity of the fuel in the tank 12 directly and particularly precisely the system 10 comprises a sensor device 43 comprising three sensors 44, 46 and 48 configured to detect the respective amounts entering and leaving the tank 12. For example, the sensors 44, 46 and 48 are configured to detect at least one parameter indicative of respective mass flows of the fuel. In particular, the sensors 44, 46 and 48 are configured as pressure sensors. The sensors 44, 46 and 48 are integrated in a fuel system of the motor vehicle, the fuel system comprising the tank 12, the filler pipe 36, and the fuel supply system. The sensor 44 is arranged in the filler pipe 36 and configured to measure the first amount of fuel flowing through the duct 38 into the tank 12. For example, the sensor 44 is configured to measure the pressure of the fuel flowing through the duct 38. The sensor 46 is arranged in the line 32 so that the sensor 46 is configured to detect the second amount of fuel flowing through the line 32 and, thus, leaving the tank 12. This means the sensor 46 is configured to detect the mass of fuel leaving the tank 12.

For example, the sensor 46 is a pressure sensor configured to measure the pressure of the fuel flowing through the line 32. Moreover, the sensor 48 is arranged in the return line and configured to detect the third amount of fuel entering the tank 12.

For example, the sensor 48 is configured as a pressure sensor which is configured to measure the pressure of the fuel flowing through the return line 40. On the basis of the detected pressures a calculation illustrated in Fig. 2 is carried out to estimate the exact quantity of fuel in the tank 12 at any instance in time. The determined quantity in the tank 12 can be displayed in, for example, the interior of the motor vehicle. In Fig. 2 the first amount of fuel flowing through the duct 38 is indicated by X(,) being a mass flow rate of fuel entering the tank 12 at any instance in time via the duct 38. Moreover, the second amount leaving the tank 12 via the line 32 is indicated by Y) being a mass flow rate of fuel leaving the tank 12 to the internal combustion engine at any instance in time via the line 32. Moreover, the third amount of fuel flowing through the return line 40 is indicated by Z() being a mass flow rate of fuel returning back to the tank 12 from the internal combustion engine at any instance in time via the return line 40. Moreover, X(,l), and are previously recorded mass flow rates or previously recorded mass flow rate values. Moreover, p is the density of the fluid, v is the velocity of the fuel at the sensor 44, P(t) is the pressure of the fuel flowing through the duct 38 and A is the cross section of the duct 38 at the sensor 44. Furthermore, Vf is the velocity of the fluid at sensor 46, P1(t) is the pressure of the fuel flowing through the line 32 and A is the cross section of the line 32 at the sensor 46. Additionally, V, is the velocity of the fuel at the sensor 48, Pr(t) is the pressure of the fluid flowing through the line 40 and Ar is the cross section of the return line 40 at the sensor 48. Thus, X(), r) and can be calculated according to: I 2 pV 12P(i) . pV 12P(i) 2 X=%pA1.; /L1(j)= %7 Y=V1pA1; V= /2PT(/);and2 =VpA 2 (t) r r The sensors 44, 46 and 48 provide respective signals indicative of the first, second and third amounts. Moreover, the system 10 comprises a processing unit 50 which is configured as, for example, an electronic control unit (ECU). The sensors 44, 46 and 48 are connected to the processing unit 50 so that the respective signals can be transmitted from the sensors 44, 46 and 48 to the processing unit 50 which receives said signals. The processing unit 50 is configured to calculate the quantity of fuel in the tank 12 on the basis of the signals and, thus, the respective amounts. Thus, the sensor device 43 is configured to detect the respective first, second and third amounts directly so that the quantity of fuel in the tank 12 can be determined directly and, thus, particularly precisely.

The motor vehicle further comprises at least one display 52 which is arranged in the interior of the motor vehicle. The display 52 is configured to display the calculated quantity of fuel in the tank 12 so as to inform the driver of the vehicle about the fuel remaining in the tank 12 particularly precisely.

List of reference signs 1 0 system 12 tank 14 primary chamber 16 secondary chamber 18 fuel pump jet pump 22 jet pump 24 filter 26 filter 28 filter line 32 line 34 directional arrow 36 filler pipe 38 duct return pipe 42 directional arrow 43 sensor device 44 sensor 46 sensor 48 sensor processing unit 52 display

Claims

Claims A method for determining the quantity of a fluid, in particular fuel, in a tank (12), the method comprising: -by means of a sensor device (43), detecting at least one first amount of fluid entering the tank (12); and -by means of the sensor device (43), detecting at least one second amount of fluid leaving the tank (12); wherein the quantity of the fluid is determined on the basis of the detected first and second amounts by means of a processing unit (50).
2. The method according to claim 1, wherein the respective amount is detected by at least one respective sensor (44, 46, 48) configured to detect at least one parameter indicative of a mass flow of the fluid.
3. The method according to claim 2, wherein the respective sensor (44, 46, 48) is configured as a pressure sensor.
4. A system (10) for determining the quantity of a fluid, in particular fuel, in a tank (10), the system comprising: -a sensor device (43) configured to detect at least one first amount of fluid entering the tank (12), and at least one second amount of fluid leaving the tank (12); and -a processing unit (50) configured to determine the quantity of the fluid on the basis of the detected first and second amounts.