Claims:We Claim:
1. A method of detecting presence of a filter in a system, said system comprising at least a pump for pumping fluid, said method comprising:

receiving (100), by a control unit a feedback signal from said pump;

converting (102), by said control unit said feedback signal into a pressure value;

comparing (104), by said control unit said converted pressure value with a data map in said control unit, said data map containing a stored pressure value in dependence of an air gap in the filter; and

checking (106), by said control unit if said converted pressure value indicates presence of filter based on said data map.

2. The method of claim 1, wherein said feedback signal from said pump is at least one of a discharge quantity of fluid, and time signal.
, 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]This invention relates to the field of filter used in systems for filtration.

Background of the invention
[0002]A filter is used for filtration of a particulates or impurities present in a fluid. The fluid may be fuel in the case of fuel injection system, and in the case of a dosing system a dosing liquid. Dosing systems are used for emission control. In the case of a dosing system, a pump is located upstream to the filter. Dosing liquid from the pump flows through the filter and into the dosing injector where it is injected into the exhaust stream. In case the filter is not present in the dosing system, there are chances of impurities to pass through the dosing system and into the exhaust thereby causing damage to the components of the dosing system.

Brief description of the accompanying drawing
[0003] Different modes of the invention are disclosed in detail in the description and illustrated in the accompanying drawing:

[0004] FIG. 1 illustrates a method of detecting presence of a filter in a dosing system.

Detailed description of the embodiments
[0005] FIG. 1 illustrates a method of detecting presence of a filter in a system. The system comprises at least a pump for pumping fluid. The method comprises receiving 100, by a control unit a feedback signal from the pump, the feedback may be received from a sensor. The feedback signal is then converted 102 into a pressure value. The control unit compares 104 converted pressure value with a data map, the data map contains a stored pressure value pump in dependence of an air gap generated in the filter. Air gap of the filter is chosen as a parameter because filter is designed to accommodate air. The fluid needs to occupy this air gap and then start filling the volume in the filter. This requires fluid to flow from the pump at a pressure that is sufficient to overcome the air gap. In the absence of filter the requirement of fluid to fill the air gap is not required and the fluid may flow directly to the dosing module for injection or in case the filter is used in a fuel injection system to a high pressure fuel injection pump. This difference in pressure of the fluid is used as an input to determine the presence of filter or the lack of the same. Air being compressible in nature, acts a dampener to the flow of fluid when air gap is present because of filter. This can result in pressure fluctuations, as the fluid has to act against the compressible nature of air to fill the volume in the filter. The control unit checks if the converted pressure value indicates presence of filter based on the data map. The feedback signal from the pump is at least one of a pressure signal of a dosing fluid, and time signal. When a system is devoid of filter, the pressure fluctuations are more in comparison to the system where there is filter, this is because air gap in the filter acts as dampener that servers to absorb or limit the pressure fluctuations. However, in the filter’s absence, the air around the filter is rapidly filled with the fluid and the dampening properties are lost very quickly because the air get compressed or escapes.

[0006]The disclosed method makes use of change in pressure of the fluid flowing through a dosing system with and without the presence of filter. During calibration in the dosing system, the fluid is made to flow from the. The parameter that is measured during calibration is the pressure at which the fluid flows through the system with and without the presence of filter. This is then recorded in the form of a data map and stored in the control unit. The variation in pressure fluctuation in a system with and without filter is taken as reference to determine the presence of filter.

[0007]For the purpose of better understanding the working of the method will be explained considering a dosing system. The said method may be used in any system where the absence of filter may lead to damage to the components of the system, like, for example but not limited to fuel injection system, dosing system. For the purpose of better understanding, the method will be explained considering two situations, presence of filter in the system and the absence of filter in the system.

[0008] In case the filter is present in the system, the control unit receives 100 the feedback signal from the pump. The control unit then converts 102 the feedback signal into a pressure value. The converted pressure value is then compared with a pressure value stored in the data map for a corresponding flow rate. If the converted value is equal to the pressure value as obtained from the data map for the corresponding flow rate, then it indicates that the fluid is overcoming the pressure due to the presence of air gap in the filter to flow through the dosing system or in other words air is acting as a dampener. This indicates the presence of filter in the dosing system.

[0009] In case the filter is not present in the system, the control unit receives 100 the feedback signal from the pump. The control unit then converts 102 the feedback signal into a pressure value. The converted pressure value is then compared with a pressure value stored in the data map for a corresponding flow rate. If the converted value is different than the pressure value as obtained from the data map for the corresponding flow rate, then it indicates that the fluid need not overcome the presence of air gap as the filter is not present. This indicates that the filter is not present in the system. With the use of the above mentioned method it is now possible to predict the presence and/ or absence of filter in systems that make use of filter. The detection of filter not being present in the system serves as a preventive measure for implementing corrective actions in order to prevent damage to the component of the dosing system.

[0010] ‘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.

[0011]It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention in terms of the type of filter used or the type of system using the filter. 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.