Claims:We Claim:
1. A method (100) for determining a deviation, said method (100) comprising at least of following steps:
sensing (101) characteristics of sound waves transmitted through a fluid in a fuel tank by a sound sensing device, and
determining (102) a deviation of a sensed sound wave characteristics by a control unit from a pre-configured sound wave characteristics.

2. A method (200) for detecting fluid mixed in fuel in a fuel tank, said method (200) comprises:
sensing (201) characteristics of sound waves transmitted through a fluid in a fuel tank by a sound sensing device;
determining (202) a deviation of a sensed sound wave characteristics by a control unit from a pre-configured sound wave characteristics;
operating (203) a valve by said control unit based on the deviation for transferring the fluid mixed in fuel to a separator;

3. The method (200) as claimed in claim 2 wherein when said valve is operated and based on the input from said sound sensing device the fluid is separated by said separator.

4. The method (200) as claimed in claim 2, wherein said fluid is selected from a group comprising urea, glycol, coolant and the like.

5. A fuel tank assembly (300) for an engine; said fuel tank assembly (300) comprising,
a sound sensing device (301) located at an internal surface of a fuel tank (302);
at least two flow paths (303, 304) from said fuel tank (302), one each for a separator (305) and a pump (306) respectively;
at least one valve (303a, 304a) for each of the at least said two flow paths (303, 304), said at least one valve is operated by a control unit (308) based on a response from said sound sensing device (301).

6. The fuel tank assembly (300) as claimed in claim 4, wherein said sound sensing device (301) is configurable for different fluids.

7. The fuel tank assembly (300) as claimed in claim 4, wherein said at least one valve (303a, 304a) is a unidirectional valve.

8. The fuel tank assembly (300) as claimed in claim 4, wherein said at least one valve (303a, 304a) is a two-way valve.

9. A control unit (308) to detect fluid mixed in fuel in a fuel tank (302), said control unit adapted to:
sense characteristics of sound wave transmitted through the fluid in a fuel tank (302) by a sound sensing device (301);
determine a deviation in sensed sound wave characteristics in comparison to a pre-configured sound wave characteristics;
operate a valve (303a, 304a) based on said deviation to transfer said fluid mixed with fuel to a separator (305).

10. The control unit (308) as claimed in claim 9 wherein separator (305) separates said fluid mixed with said fuel when said valve (303a, 304a) is operated and based on the input from said sound sensing device (301).
, Description:Complete Specification:
The following specification describes and ascertains the nature of this invention and the manner in which it is to be performed.
Field of the invention
[0001] The invention relates to a method for detecting fluid mixed in fuel in a fuel tank, a control unit and a fuel tank assembly.

Background of the invention
[0002] In a vehicle, there are at least two tanks available, one for the fuel for the engine and other for the regeneration process i.e. to store the diesel exhaust fluid for example urea. There are high chances that the fuel, which is supposed to be filled in fuel tank, is filled in the other tank. Therefore, there is a need for solutions to prevent filling of the urea in fuel tank.

[0003] A patent application US 20150308952 discloses a urea concentration sensor. A sensor to measure a liquid. The sensor may include a light source operably coupled to a lumen disposed in a liquid solution. The light source configured to emit light and communicate the light to the lumen. A light detector operably coupled to the lumen, the light detector configured to receive at least a portion of the light from the lumen and a controller configured to determine a concentration or quality of the liquid solution based on the light emitted by the light source and the portion of light received by the light detector.

Brief description of the accompanying drawings:
[0004] Different mode of the invention is disclosed in detail in the description and illustrated in the accompanying drawings:
[0005] FIG. 1 illustrates a method for determining a deviation, according to an embodiment of the invention.
[0006] FIG. 2 illustrates a method for detecting fluid mixed in fuel in a fuel tank, according to an embodiment of the invention.
[0007] FIG. 3 illustrates a fuel tank assembly, according to an embodiment of the invention.

Detailed description of the embodiments
[0008] Figure 1 illustrates a method for determining a deviation according to an embodiment of the disclosure. The method comprised at least of following steps: In step 101, a characteristics of sound waves transmitted through the fluid in a fuel tank 302 (shown in Fig. 3) is sensed by a sound sensing device 302 (shown in Fig. 3). In step 102, a deviation of a sensed sound wave characteristics from a pre-configured sound wave characteristics is determined by a control unit 308 (shown in Fig. 3).

[0009] Figure 2 illustrates a method for detecting fluid mixed in fuel in a fuel tank. The method comprised at least of following steps: In step 201, the characteristics of sound waves transmitted through the fluid in the fuel tank 302 is sensed by the sound sensing device 301. In step 202, the deviation of the sensed sound wave characteristics from the pre-configured sound wave characteristics is determined by the control unit. In step 203, the control unit operates a valve 303a, 304a (shown in Fig. 3) based on the deviation in sound wave characteristics, for transferring the fluid mixed with the fuel to a separator. And based on the input from the sound sensing device and operation of the valve, a separator 305 separates the fluid mixed in the fuel. In addition, due to the density of the two different fluids for example in case of diesel and urea, the urea remains above or below the fuel. It does not mix, but two separate fluids are in the same tank.

[0010] In the method 200, the pre-configured sound waves refers to the speed of sound in a fluid is of meter per second. The sound waves have different speed in different kinds of fluid.

[0011] Here in this method 200, the fluid is selected from a group comprising urea, glycol, coolant and the like. The fluid refers to any fluid apart from the fuel in the fuel tank 302 for example urea, ethylene glycol, washer fluid, brake fluid, salt water etc.

[0012] The method 200 disclosed above is explained in detail here for a case where a fluid apart from fuel is filled in the fuel tank 302. The sound sensing device 301 senses the change in characteristics of sound waves transmitted through the fluid in a fuel tank 302. The control unit determines the deviation of sensed sound wave characteristics from the pre-configured sound wave characteristics and operates the valve 303a, 304a. The fluid mixed with fuel flows through the valve 303a, 304a to the separator where the fuel is separated from the fluid, and clean fuel flows back to the fuel tank 302 and the fluid flows to another tank 307 (shown in Fig 3. Once the separation is done, the control unit 308 checks for the deviation to ensure complete separation and the method is followed again and the separation is done again or until the fluid is completely separated.

[0013] Figure 3 illustrates a fuel tank assembly 300 according to an embodiment of the disclosure. A fuel tank assembly 300 for an engine comprises the sound sensing device 301 located on an internal surface of the fuel tank 302. At least two flow paths (303, 304) from the fuel tank 302 is provided, one each for the separator 305 and a pump 306, respectively. The fuel tank assembly 300 for the engine further comprises at least one valve (303a, 304a) for each of the two flow paths (303, 304). A control unit 30based on the response from the sensing device operates the valve (303a, 304a).

[0014] In the fuel tank assembly 300, the sound sensing device 301 is configurable for different types of fluids. The speed of sound in different types of fluid is different. For example, the speed of sound in urea is 1630 meter per second, and the speed of sound in brake fluid is 1530 meter per second. Likewise, the sound sensing device 301 is configured with values and based on the response of the sound sensing device 301, the control unit determines the kind/type of fluid filled in the fuel tank 302.

[0015] According to an embodiment of the disclosure, in the fuel tank assembly 300, one flow path 303 is connected from fuel tank 302 to the pump 306 and one flow path 304 is connected to the separator 305. Each flow path (303, 304) has a valve (303a, 304a) which is operated based on the signal from the control unit. When the deviation in the sound wave characteristics is detected based on the signal transmitted by the sound sensing device 301, the control unit operates the valve (303a, 304a). The valve 303a in the flow path 303 from fuel tank 302 to the pump 306 is closed and the flow of the fluid from the fuel tank 302 to the pump 306 is stopped. On the other hand, the valve 304a in the flow path 304 from the fuel tank 302 to the separator 305 is opened so the fluid mixed with fuel flows to the separator 305.

[0016] According to an embodiment of the disclosure, the separator 305 here refers to any device, which is used to separate the fluid from the fuel. For example, the separator 305 is a urea separator, which separates the urea mixed with the fuel. The use of separator 305 is not restricted to this method only. The separator 305 is used in other applications also for example, in medical field under dialysis treatment.

[0017] According to an embodiment of the disclosure, in the fuel tank assembly 300, the valves (303a, 304a) are a unidirectional valve, so once the valves (303a, 304a) are operated by the control unit 308, the valves (303a, 304a) allow the flow only in one direction.

[0018] According to an embodiment of the disclosure, in the fuel tank assembly 300, the valves (303a, 304a) are a two-way valve. Therefore, the valves (303a, 304a) allows the flow of the fluid mixed with the fuel in two directions depending upon the requirement of the process.

[0019] According to an embodiment of the disclosure, the control unit 308 is used to detect fluid mixed with fuel in the fuel tank 302. The control unit 308 is adapted to sense the characteristic of sound wave transmitted through the fluid in the fuel tank 302 by the sound sensing device 301, i.e. a sensor, determine the deviation in the sensed sound wave characteristics from pre-configured sound wave characteristics. The control unit 308 further adapted to operate the valve 303a, 304a based on the deviation in sound wave characteristics, for transferring the fluid mixed with fuel to the separator. The separator 305 separates the fluid mixed with the fuel when the valve 303a, 304a is operated, which is in turn operated based on the input from the sound sensing device 301.

[0020] By using this above disclosed method 200 by the control unit and the fuel tank assembly 300, the life and performance of a fuel injection system of a vehicle or other devices are increased. As the fluid mixed with fuel i.e. the contaminated fuel is pumped to a separator and not to the engine. The method 200 prevents the fuel injection system to operate further if the mixing of any fluid in the fuel is detected, that further saves the life of the overall components of the fuel injection system, which are not covered under warranty.

[0021] ‘Adapted’ or ‘arranged’, in the context of the instant disclosure, refers to the technical capability or the technical capacity of a component, in relation to which the term ‘adapted’ or ‘arranged’ is used, to carry out or executed a specified action or actions, upon the requirement of the specified action or actions to be carried out or executed. Moreover, the usage of the term ‘adapted’ or ‘arranged’ here, is in reference with the normal technical capability or technical capacity of the component, imparted by the design or the structure or the composition of the component, and not in reference with any special or extraneous capability or capacity, beyond the scope of the normal technical capability or technical capacity. Therefore, there is a need to address this problem

[0022] It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention. Many such embodiments and other modifications and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims