Claims:We Claim:
1. A method (100) for detecting a theft of diesel exhaust fluid from a tank, said method (100) comprising at least of following steps:
sensing (101) a refill quantity of diesel exhaust fluid in a tank by a level sensor;
comparing (102) the sensed refill quantity with consumed diesel exhaust fluid as per a pre-defined characteristic, and
detecting (103) a theft, by a controller, based on said comparison.

2. The method (100) as claimed in claim 1, wherein said pre-defined characteristics are dependent on the stored dimensions and tolerance during quantity measurement.

3. A method for determining quality of diesel exhaust fluid in a tank, said method comprising:
sensing (201), by a controller, a refill of reducing agent in said tank through a level sensor, and
determining(202), by said controller, quality of said diesel exhaust fluid based on an availability of at least one selected from a group comprising a quality sensor and a Selective Catalyst Reduction (SCR) adaptation factor.
4. The method (200) as claimed in claim 4, wherein said SCR adaptation factor is dependent on a self-learning factor of said SCR system.

5. A controller to determine theft of reducing agent from a tank, the controller adapted to
detect a refill quantity of said reducing agent, by a level sensor;
compare said refill quantity of said reducing agent with consumed quantity of reducing agent as per pre-defined characteristics, and
determine a theft of said reducing agent based on said comparison.

6. A controller to determine quality of reducing agent in a tank, said controller adapted to
sense a refill of reducing agent in said tank through a level sensor; and
determine a quality of said reducing agent based on an availability of at least one selected from a group comprising a quality sensor and a Selective Catalyst Reduction (SCR) adaptation value.
, 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 a theft of diesel exhaust fluid from a tank of a vehicle.

Background of the invention
[0002] In the automotive applications, the reducing agent or Diesel Exhaust Fluid (DEF) is obtained from a source. The urea is highly soluble in water and is added to the exhaust gas in the fluid form.. A modular Selective Catalytic Reduction (SCR) system is used to meter the DEF into exhaust path. The DEF filled in the tank is used for regeneration purpose. Now, there is a need for a method to track the refilled quantity of reducing agent..

[0003] A prior art patent application US9382828 discloses a system, method and apparatus for after treatment system monitoring. A method includes determining whether a urea refill event is detected, and clearing a quality accumulator value and clearing a latching abort command. The method includes determining whether urea fluid quality check and abort conditions are met. In response to the abort conditions not being met, incrementing the urea quality accumulator according to an amount of urea being injected, and comparing the accumulated urea quantity to a low-test threshold.

Brief description of the accompanying drawings:
[0004] Different modes of the invention are disclosed in detail in the description and illustrated in the accompanying drawings:
[0005] FIG. 1 illustrates a method for detecting theft of diesel exhaust fluid, according to an embodiment of the invention, and
[0006] FIG. 2 illustrates a method of determining quality of the diesel exhaust fluid, according to an embodiment of the invention.

Detailed description of the embodiments

[0007] Figure 1 illustrates method for detecting a theft of diesel exhaust fluid in a tank according to an embodiment of the invention. The method comprises at least of following steps. In step 101, a level sensor senses the refill quantity of diesel exhaust fluid in the tank. In step 102, the sensed refill quantity is compared with the consumed quantity as per a pre-defined characteristic by a controller. In step 103, the controller detects 103 a theft based on the comparison, such as, if compared value is more/less than a defined/threshold value.

[0008] In the method, the consumed quantity refers to the quantity of the reducing agent consumed in the previous cycle of the SCR process. The value stored in a memory element, and is recovered by the controller. The pre-defined characteristics here are the values dependent on the stored dimensions and the tolerance during the quality measurement of diesel exhaust fluid. The stored dimensions are previous cycle values based on which the deviation is determined. In every cycle, there are allowable deviation, which takes care of the variation in cycle time and the estimated quantity of the diesel exhaust fluid. The allowable deviation also has a threshold value. The tolerances occur while measuring the diesel exhaust fluid quantity.

[0009] For example, the previous cycle diesel exhaust fluid consumed value and the refilled quantity value of present cycle is added and then compared with the tolerances and the allowable deviation. Then the theft is detected if the compared value is greater/ less than a defined/threshold value. If the compared value is less than the defined value then there is no theft.

[0010] In the method 100, for an instance when the diesel exhaust fluid is filled in the tank by a source, then the level sensor senses the refill quantity of the diesel exhaust fluid and then the controller does the comparing from the previous cycle value and then the theft is detected.

[0011] In the method 100, the defined value is from a set of Binary, Boolean or the like. The defined value is 0 or 1 based on the compared value.

[0012] Figure 2 illustrates a method for determining quality of diesel exhaust fluid in the tank, according to an embodiment of the invention. The method comprised at least of following steps. In step 201, the level sensor senses the refill of the diesel exhaust fluid in the tank. In step 202, the controller determines the quality of said diesel exhaust fluid based on an availability of at least one selected from a group comprising a quality sensor and a Selective Catalyst Reduction (SCR) adaptation factor.

[0013] In the method, the SCR adaptation factor is dependent on the self-learning function of the SCR system. The self-learning function refers to a continuous function performed at every cycle for analyzing the process of every cycle based on the response from the SCR adaptation factor. The SCR adaptation factor decreases or increases based on the quality of diesel exhaust fluid filled in the tank. SCR Adaptation factor is monitored for dilution or deterioration of diesel exhaust fluid filled in the tank immediately after the refill has occurred in absence of diesel exhaust fluid quality sensor.

[0014] In the method, SCR adaptation factor which is usually set to one value considering desired diesel exhaust fluid quality, would increase or decrease based on the self-learning function of SCR system of the previous cycle on meeting the release criteria. On detection of a successful refill of tank, and immediately if SCR adaptation state is active and the SCR adaptation factor is observed to be incrementing, it indicates that the diesel exhaust fluid quality is deteriorated. This behavior of the system is monitored to indicate the fleet owner or the concerned person on the diesel exhaust fluid quality deterioration filled in the diesel exhaust fluid tank.

[0015] According to an embodiment of the invention a controller is used to determine theft of diesel exhaust fluid from a tank, the controller adapted to detect a refill quantity of diesel exhaust fluid by a level sensor. The controller further compares the refill quantity of diesel exhaust fluid with consumed quantity of diesel exhaust fluid as per pre-defined characteristics and then determines a theft of diesel exhaust fluid based on the comparison.

[0016] According to an embodiment of the invention a controller to determines quality of diesel exhaust fluid in a tank. The controller adapted to sense a refill of diesel exhaust fluid in tank through a level sensor. The controller further determines a quality of the diesel exhaust fluid based on an availability of at least one selected from a group comprising a quality sensor and a Selective Catalyst Reduction (SCR) adaptation value.

[0016] By using the above-disclosed methods, the theft of diesel exhaust fluid in a tank is detected and the quality check can be maintained so that the efficiency of the SCR system is achieved. The theft here includes the loss of diesel exhaust fluid when the vehicle is in stand still position or less quantity filled at the refill station etc.

[0016] ‘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.

[0017] 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.