Claims:We Claim:

1. A pressure switch (101) for a fuel filter (100), said pressure switch (101) comprising a housing means (102) and an electrical connector (103), said electrical connector (103) connected to an indicating means on the dashboard of a vehicle.

2. The pressure switch (101) for a fuel filter (100) as claimed in claim 1, where the housing means (102) comprises:
A first opening (104) in fluid communication with an inlet of the fuel filter (100);
A second opening (105) in fluid communication with an outlet of the fuel filter (100);
A piston (106) located proximate to the second opening;
A spring (107) mounted on the piston (106); and at least
An elastically flexible diaphragm (108) located proximate to the first opening;
Characterized in that housing means (102):
a set of metallic contacts (110);
A plunger (109) located proximate to the first opening, said plunger (109) adapted to interact with the set of metallic contacts (110).

3. The pressure switch (101) for a fuel filter (100) as claimed in claim 1, where the electrical connector (103) comprises:
A mating feature (1031) that engages with the housing means (102); and at least
An electrical circuit (1032) comprising at least a resistor and a battery.

4. The pressure switch (101) for a fuel filter (100) as claimed in claim 1, where the housing means (102) and the electrical connector (103) are affixed to each other.

5. The pressure switch (101) for a fuel filter (100) as claimed in claim 1, where the indicating means gives an audio or visual indication to a user.

6. A fuel filter (100) for vehicle a having at least an inlet and an outlet, where the inlet is in fluid communication with a first opening (104) of a pressure switch (101), the outlet is in fluid communication with a second opening (105) of a pressure switch (101), said pressure switch (101) comprising a housing means (102) and an electrical connector (103), said electrical connector (103) connected to an indicating means on the dashboard of a vehicle.

, 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 present disclosure relates to a pressure switch for a fuel filter.
Background of the invention
[0002] Filtered Fuel is a primary need for functionality & durability of fuel injection components. Imperfect Filtration leads to malfunction of components which further affects engine performance. The filter in due course of time becomes clogged due to the trapping of suspended particles as they pass through a porous medium. This trapping progressively impedes and eventually stops the flow of the fuel. Conventional methods of detecting filter clogging use pressure sensors near the inlet and outlet of the fuel filter to measure a differential pressure across the filter. However this method is expensive and not robust.

[0003] Indian patent application IN04189CH2014A – Fuel filter clogging indicator discloses a fuel filter clogging indicator. The filter clogging indicator comprises a chamber comprising a first end and a second end, the first end in fluid communication with an inlet of a filter, the second end in fluid communication with an outlet of the filter. A piston is located within the chamber, the piston being biased with a compressible member and adapted to translate within the chamber. An indicating means is located on the piston, wherein the indicating means is adapted to translate with the piston and indicate an extent to which the filter is clogged.

Brief description of the accompanying drawings
[0004] An embodiment of the invention is described with reference to the following accompanying drawings:
[0005] Fig. 1 depicts a fuel filter (100) with a pressure switch (101).
[0006] Fig. 2 depicts a pressure switch (101) for a fuel filter (100).

Detailed description of the drawings

[0007] Figure 1 depicts a fuel filter (100) for vehicle. The fuel filter (100) has at least an inlet and an outlet, without prejudice to the other components of the fuel filter (100). The inlet is in fluid communication with a first opening (104) of a pressure switch (101). The outlet is in fluid communication with a second opening (105) of the pressure switch (101). The pressure switch (101) comprises a housing means (102) and an electrical connector (103). The electrical connector (103) is connected to an indicating means on the dashboard of a vehicle.

[0008] Figure 2 depicts a pressure switch (101) for a fuel filter (100). The pressure switch (101) comprises a housing means (102) and an electrical connector (103). The electrical connector (103) is connected to an indicating means on the dashboard of a vehicle.

[0009] The housing means (102) further comprises a first opening (104), a second opening (105), a piston (106), a spring (107), an elastically flexible diaphragm (108), a plunger (109) and at least a set of metallic contacts (110). The first opening (104) is in fluid communication with an inlet of the fuel filter (100). The second opening (105) is in fluid communication with an outlet of the fuel filter (100).

[0010] The piston (106) is located proximate to the second opening (105). The spring (107) is mounted on the piston (106). The elastically flexible diaphragm (108) is located proximate to the first opening (104). A very important non limiting feature of the invention is the plunger (109). The plunger (109) is located proximate to the first opening. The plunger (109) is adapted to interact with the set of metallic contacts (110).

[0011] The electrical connector (103) comprises a mating feature (1031) and at least an electrical circuit (1032). The mating feature (1031) engages with the housing means (102). When the mating feature (1031) us engaged with housing means (102), it connects the set of metallic contacts (110) with the electrical circuit (1032). The electrical circuit (1032) comprises at least a resistor and a battery. The housing means (102) and the electrical connector (103) are affixed to each other.

[0012] In an embodiment the housing means (102) and the electrical connector (103) are affixed to each other by an interference fit using two sealing rings. In another embodiment housing means (102) and the electrical connector (103) are affixed to each other by means of a threaded fit. Here the electrical connector (103) is tightened on to the housing means (102) using a threaded feature on the housing means (102). Furthermore sealing rings are used to prevent any leakages. In another embodiment the housing means (102) and the electrical connector (103) are affixed to each other using a snap fit. In yet another embodiment, the housing means (102) and the electrical connector (103) are affixed to each other by the process of crimping.

[0013] The indicating means as mentioned above gives an audio or visual indication to a user regarding clogging of the fuel filter (100). The pressure switch (101) for the fuel filter (100) also has at least two sealing rings (111) mounted on the housing.

[0014] The delta pressure switch (101) is designed to detect a degree of clogging in the fuel filter (100). The delta pressure switch (101) works on the principle of detecting pressure difference between clean and dirty side of the filter element. The clean side of the fuel filter (100) is usually the outlet and the dirty side is the inlet. This pressure difference between the inlet and outlet translates to a movement of the plunger (109).

[0015] When the filter is not clogged the pressure difference impinging upon the elastically flexible diaphragm (108) will be within a pre-defined threshold. In this condition the spring (107) will be in a relaxed condition and will push the plunger (109) towards the metallic contacts (110). In this condition the plunger (109) is adapted to interact with the metallic contacts. The plunger (109) in this condition will be in contact with the metallic contacts (110). This will complete the electrical circuit (1032) of the electrical connector (103) as illustrated in figure 3. Hence the output voltage from the electrical connector (103) will be less than the voltage applied to one of the metallic contacts (110). For example consider the voltage applied to one of the metallic contacts (Vcc) is 5 volts. The completion of the circuit will cause the resistance posed by the resistor (for example its value is taken as 10Kohms) to be felt in the circuit. Hence the value of output voltage in this case for the value of resistance with 10 Kohms will be less than 1.3 volts approximately (Figure 4).

[0016] When the filter is in clogged condition the pressure difference between the first opening (104) and the second opening (105) will be more than a pre-determined value. This pressure difference impinging upon the elastically flexible diaphragm (108) will translate to the movement of plunger (109) towards the spring (107). This will cause the plunger (109) to loose contact with the metallic contacts (110). This will open the electrical circuit (1032) of the electrical connector (103) as shown in figure 3. Hence the output voltage from the electrical connector (103) will be equal to the voltage applied to one of the metallic pins. For example consider the voltage applied to one of the metallic pins (Vcc) is 5 volts. Since the circuit is open the resistance posed by the resistor (for example its value is taken as 10Kohms) will not come into play. Hence the value of output voltage will be 5 volts (Figure 4).

[0017] The higher voltage output is given to the indicating means on the dashboard of the car. The indicating means through an audio or visual means conveys to the user that the filter is clogged and needs to be replaced. For example in an embodiment the higher voltage output from the electrical connects lights up a light emitting diode (LED) on the dashboard of the vehicle indicating clogging of the fuel filter (100).

[0018] This idea to develop a pressure switch (101) for a fuel filter (100) is indicative of health of the fuel filter (100). This is an accurate and more precise method of determining filter clogging as it takes into account actual health of filter. This method eliminates the need of special filter clogging sensors to be installed inside the internal combustion engine, hence offering a cost-effective and more accurate solution for the problem of checking the degree of filter clogging.

[0019] It must be understood that the embodiments explained in the above detailed description are only illustrative and do not limit the scope of this invention. Any modification to the pressure switch (101) for a fuel filter (100) are envisaged and form a part of this invention. The scope of this invention is limited only by the claims.