FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION (See section 10, rule 13)
1. Title of the invention: AUTOMATIC WATER DRAIN (AWD) MECHANISM FOR A
FUEL FILTER ASSEMBLY
2. Applicant(s)
NAME NATIONALITY ADDRESS
CLARCOR INDIA PVT. Indian Plot No. F-3, Chakan MIDC
LTD. Phase - II, Village : Vasuli,
Tal : Khed, Pune - 410 501, Maharashtra, India
3. Preamble to the description
COMPLETE SPECIFICATION
The following specification particularly describes the invention and the manner in which it
is to be performed.

TECHNICAL FIELD
[0001] The present subject matter relates to a fuel filter assembly, and
particularly to draining water from the fuel filter assembly.
BACKGROUND
[0002] Generally, an engine includes a fuel pump and a fuel injector for
supplying pressurized fuel to the engine. Fuel contaminated with water and dirt
causes damage to the fuel pump and the fuel injector of the engine, and also may lead
to reduced efficiency of the engine. So, it becomes vital to ensure that only fuel of an
acceptable purity is pumped into the engine to improve the engine’s performance.
[0003] For filtering out contaminants contained in fuel and for separating the
water from the fuel, the engine is equipped with a fuel filter. The fuel filter is positioned between a fuel tank and the fuel pump. The fuel filter contains an element, generally in the form of a paper, to separate the dirt and dust particles from the fuel. The water is usually collected in a water bowl or collection reservoir that is coupled to a bottom of the fuel filter. When the water collected in the water bowl reaches to a predetermined level, it needs to be drained. The water can be drained manually or automatically.
BRIEF DESCRIPTION OF THE DRAWINGS
[0004] Fig. 1 illustrates a schematic representation of a conventional fuel
system of an engine which includes a fuel filter assembly of the present subject matter.
[0005] Fig. 2 illustrates a cross-sectional view of a filter housing and a water
bowl of a fuel filter housing, according to a first embodiment of the present subject matter.

[0006] Fig. 3 illustrates a cross-sectional view of a water bowl of a fuel filter
assembly, according to a first embodiment of the present subject matter.
[0007] Figs. 4A and 4B illustrate a water bowl, a solenoid, and a float
assembled together in a cross-sectional view further illustrating a flow path for water,
according to a first embodiment of the present subject matter.
[0008] Figs. 5A and 5B illustrate a water bowl and a solenoid, assembled
together in a cross-sectional view, further illustrating a flow path for water, according
to a second embodiment of the present subject matter.
DETAILED DESCRIPTION
[0009] Conventionally, a fuel filter includes a water level sensor disposed
within a water bowl to sense a level of water. An electric circuit communicating with the sensor opens a drain valve in response to a logic signal received from the sensor, to allow draining of water from the water bowl. Generally, a solenoid valve is used as the drain valve to drain water. If pressure on water is greater than ambient pressure, water can easily drain out of the water bowl when the drain valve is open. However, if the pressure on the water is less than the ambient pressure, then positive pressure must be applied on water, so that water can be drained out of the water bowl countering the pressure difference. To create this positive pressure, an air vent disk, normally in a close position, is provided on a top of the water bowl. Once the drain valve is operated, the air vent disk is lifted upwards to an open position to allow creation of an air passage inside the water bowl. The air passage creates the positive pressure on water which results in a continuous flow of water through the drain valve. An introduction of the air passage, however, may disturb an operation of an engine. When a driver tries to start the engine, the air trapped into a fuel line acts as a lock, preventing a normal supply of the fuel to the engine. This makes driving a laborious exercise.

[0010] The present subject matter discloses a fuel filter assembly for
removing contamination and separating water from fuel. An illustrative example of
the fuel filter assembly comprises a filter housing and a water bowl. A filter element
enclosed within the filter housing removes the contaminants from fuel. Fuel is then
allowed to flow through the water bowl to separate water from fuel.
[0011] An illustrative example of the water bowl includes a drain passage
which divides the water bowl into two separate chambers, namely a first chamber and a second chamber. The water bowl also includes a plunger activated by a solenoid and a float to drain water which is accumulated in the water bowl. When the plunger is not activated, water flows from the filter housing to the inner chamber and from the inner chamber to the outer chamber. In this position of the plunger, a flow path from the outer chamber to a water outlet is covered by the plunger and water is not allowed to flow via this path. As a result, water starts accumulating in the outer chamber. As water reaches to a predetermined level, a water level sensor placed within the outer chamber detects the level and sends a signal to an Electronic Control Unit (ECU). Upon receiving the signal from the water level sensor, the ECU energizes the solenoid, which in turn activates the plunger. In its activated position, the plunger slides in an upward direction to stop the flow of water from the inner chamber to the outer chamber and creates a path for water from the outer chamber to the water outlet. Since there is fuel above the float, the float generates pressure on water to drain water through the path from the outer chamber to the water outlet.
[0012] Fig. 1 illustrates a schematic representation of a conventional fuel
system of an engine which includes a fuel filter assembly 100 of the present subject matter. In the illustrated embodiment, the engine is an internal combustion engine and fuel is diesel, but it should be appreciated that the fuel filter assembly 100 can be adapted for use with other types of engines and fuels. The fuel system includes a fuel tank 102 that supplies fuel to the engine. A fuel pump 104 is used to pump fuel from

the fuel tank 102 to the engine. A return line 106 provides a fuel return path from a plurality of injectors 108 to the fuel tank 102.
[0013] The fuel filter assembly 100 includes a filter head 110, a filter housing
112, and a water bowl 114. The filter head 110 is mounted on the engine and supports
entire fuel filter assembly 100. The filter head 110 includes an inlet 116 and an outlet
118. The fuel filter assembly 100 is positioned in series with fuel lines. The inlet 116
fluidly connects the fuel filter assembly 100 to the fuel tank 102 and the outlet 118
fluidly connects the fuel filter assembly 100 to the fuel pump 104.
[0014] In a typical implementation, fuel is drawn from the fuel tank 102 to the
fuel filter assembly 100 located at an upstream of the fuel pump 104. Fuel then passes
to the plurality of injectors 108 located on a pressure side or downstream of the fuel
pump 104. Surplus fuel that is not sent to the plurality of injectors 108 and not burnt
in cylinders flows back to the fuel tank 102 via the return line 106.
[0015] Fig. 2 illustrates a cross-sectional view of a filter housing 112 and a
water bowl 114 of a fuel filter assembly, according to a first embodiment of the present subject matter. The filter housing 112 includes an element 200 which separates out contaminants in fuel passing through the filter housing 112. The element 200 is an annulus of pleated paper element or any other form of a filter medium which would be suitable for separating out contaminants. The element 200 is housed between a first end 202 and a second end 204 of the filter housing 112. The first end 202 of the filter housing is cup shaped and made up of circular sheet metal plates for supporting the filter housing 112. An O-ring (not shown) is provided between the first end 202 and the filter housing 112 in order to create a seal and to prevent escape of fuel. A cap 206 of the water bowl 114 is coupled to the second end 204 of the filter housing 112 by a threaded coupling. An O-ring or similar seal (not shown) is provided between the cap 206 of the water bowl 114 and the second end 204 of the filter housing 112 to guard against leakage.

[0016] Fig. 3 illustrates a cross-sectional view of a water bowl 114 of a fuel
filter assembly, according to a first embodiment of the present subject matter. The
water bowl 114 comprises a container 300 and a cap 206. The cap 206 has an
aperture 302 to allow fuel to enter into the water bowl 114. In one implementation,
the cap 206 has exterior threads on its protruding portion to engage the water bowl
114 to the second end 204 of the filter housing 112. A drain passage 304 is provided
in the water bowl 114 which divides the water bowl 114 into an inner chamber 306
and an outer chamber 308. The drain passage 304 is aligned to the aperture 302 of the
cap 206 in such a way that fuel enters into the inner chamber 306. The drain passage
304 includes a first opening 310 and a second opening 312 through its side walls.
Both the openings provide respective passages for flow of fuel from the inner
chamber 306 to the outer chamber 308. The side walls of the drain passage 304 are
hollow to accommodate a solenoid 314. The solenoid 314 gets energized when
electrical signals are applied to it. A plunger 316 is slidably disposed inside the drain
passage 304 and slides along a longitudinal axis. When the plunger 316 is not
activated, water flows from the inner chamber 306 to the outer chamber 308 through
the second opening 312 of the drain passage 304. When the plunger 316 is activated,
the plunger 316 slides in an upward direction to provide a passage for water in the
outer chamber 308 to flow to a water outlet 318. A return spring 320 is disposed
between the plunger 316 and the cap 206 to bias the plunger 316 away from the cap
206. To improve the effectiveness of the plunger 316, the plunger 316 is provided
with an O-ring 322 disposed about a perimeter of the plunger 316. The O-ring 322
ensures a seal between the plunger 316 and the drain passage 304. The O-ring 322
thereby prevents water from escaping from the inner chamber 306.
[0017] A float 324, having density lower than density of water and greater
than density of fuel, is located inside the outer chamber 308. Because of the differences in densities of the float 324, water, and fuel, the float 324 defines a phase boundary between water and fuel. Water is pressurized by the float 324, because fuel

that is accumulated above the float 324 creates a downwards pressure on the float 324. Therefore, unlike in the conventional fuel filter assembly, no air inlet is required to provide the pressure on water. The operation of the float 324 is described in greater detail with respect to Figs. 4A and 4B.
[0018] The water bowl 114 also includes a water level sensor 326 that is
supported on one of the side walls of the water bowl 114. The water level sensor 326 detects a level of water when water reaches to its predetermined level. Based on the detection, the water level sensor 326 sends a signal to an Electronic Control Unit (ECU) (not shown). The ECU checks for faults in a battery, the water level sensor, and the solenoid. In response to the signal received from the water level sensor 326, the ECU sends a signal to the solenoid 314. The solenoid 314 activates the plunger 316 upon receiving the signal from the ECU. In the activated position of the plunger 316, water, under the pressure of the float 324 and the fuel above it, flows from the outer chamber 308 to the water outlet 318 through the second opening 312 of the drain passage 304 for a predetermined time. A length of time for which the plunger 316 is activated is selected suitably to ensure that the float 324 does not fall below a minimum level, defined as a dead-space. The length of time for which the plunger 316 is activated may be proportional to volume of water in the water bowl 114 and the pressure applied on water by the float 324.
[0019] Figs. 4A and 4B illustrate the water bowl 114, the solenoid 314, and
the float 324 assembled together in a cross-sectional view further illustrating a flow path for water, according to a first embodiment of the present subject matter. As can be seen from the Fig. 4A, the float 324 is at a lower level and the plunger 316 is not activated. In this position, fuel from the filter housing 112 enters into the inner chamber 306 through the aperture 302. As water is denser than fuel, water tends to flow downwards through the inner chamber 306, whereas fuel enters into the outer chamber 308 through the first opening 310 in the drain passage 304. As the flow of water gets obstructed by the plunger 316, water enters into the outer chamber 308

through the second opening 312 in the drain passage 304. Water accumulating into the outer chamber 308 forces the float 324 to move in upward direction. In this way, water starts accumulating below the float 324 and fuel starts accumulating above the float 324.
[0020] As can be seen from Fig. 4B, the float 324 continues to move in the
upward direction until water reaches at its predetermined level. The water level
sensor 326 detects this level and sends the signal to the ECU. Upon receiving the
signal from the water level sensor 326, the ECU sends the signal to the solenoid 314,
which in turn activates the plunger 316. This causes the plunger 316 to slide in the
upward direction with respect to its earlier position (as shown in Fig. 4A). This
allows water, under the pressure of the float 324, to flow from the outer chamber 308
to the water outlet 318 through the second opening 312 of the drain passage 304.
[0021] The water filter assembly, in accordance with the first embodiment of
the present subject matter, allows water to be drained with the help of pressure created by the float. As no air vent disks are used to create the positive pressure on water, air does not get trapped into the fuel line to prevent the normal supply of fuel to the engine and disturb the operation of the engine.
[0022] Figs. 5A and 5B illustrate a water bowl 502 and a solenoid 504,
assembled together in a cross-sectional view, further illustrating a flow path for water, according to a second embodiment of the present subject matter. The second embodiment is substantially same as the first embodiment illustrated in Figs. 2, 3, 4A, and 4B, with the exception that the float 324 has not been used. The water bowl 114 of the first embodiment may be replaced with the water bowl 502 of the second embodiment, as shown with respect to Fig. 1. As can be seen from Fig. 5A, in a normal position, a plunger 506 is not activated. In this position, fuel from the filter housing 112 (as shown in Fig. 1) enters into the water bowl 502 through an aperture 508. As water is denser than fuel, water contained in fuel tends to flow downwards and fuel floats on top of water. Water keeps accumulating in the water bowl 502 until

water reaches at its predetermined level. The water level sensor 510 detects this level and sends the signal to the ECU. Upon receiving the signal from the water level sensor 510, the ECU sends the signal to the solenoid 504, which in turn activates the plunger 506. This causes the plunger 506 to slide in the upward direction with respect to its earlier position (as shown in Fig. 5B). This allows water to flow from the water bowl 502 to a water outlet 512.
[0023] Water drained out of the water bowl may contain a low amount of
fuel. A secondary mesh (not shown) along with oil sorbent pads (not shown) may be
utilized below the water outlet to collect this fuel. The secondary mesh may comprise
Teflon coated steel having pore size equal to 30-100 micron. The secondary mesh
ensures that no dust is entered. The oil sorbent pads recover fuel either by adsorption
in which fuel is attracted to a surface and adhered to it, or by absorption in which fuel
penetrates into pores of the oil sorbent pads. In either case, water is repelled by the oil
sorbent pads. The oil sorbent pads may be made up of polypropylene.
[0024] It will be appreciated by those skilled in the art that the water drain
mechanism for the fuel filter assembly of the present invention provides numerous advantages. The mechanism of the present invention automatically senses when there is a need to remove separated water from the water bowl and automatically initiates such a removal process. There is no requirement that the driver or other service technician be responsible for such water removal, because such removal takes place automatically, even if the vehicle is in operation.
[0025] While the invention has been illustrated, and described in detail in the
drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected.

I/We Claim:
1. A fuel filter assembly (100) for separating water from fuel, the fuel filter
assembly (100) comprising:
a filter housing (112) having a first end (202), a second end (204), and an element (200) housed between the first end (202) and the second end (204); and
a water bowl (114) removably coupled to the filter housing (112) at the second end (204), the water bowl (114) comprising:
a drain passage (304) in communication with the second end (204) of the filter housing (112), wherein the drain passage (304) divides the water bowl (114) into an inner chamber (306) and an outer chamber (308);
a plunger (316) slidably disposed within the drain passage (304), wherein the plunger (316), when activated, opens a passage for water in the outer chamber (308) to flow to the water outlet (318);
a water level sensor (326) disposed in the outer chamber (308), wherein the water level sensor (326) activates the plunger (316) when a water level in the outer chamber (308) reaches a predetermined level;
a float (324) located inside the outer chamber (308), wherein the float (324) creates a positive pressure on the water flowing to the water outlet (318) during the activated state of the plunger (316).
2. The fuel filter assembly (100) as claimed in claim 1, wherein the drain
passage (304) includes a first opening (310) to allow a flow of fuel from the inner
chamber (306) to the outer chamber (308).

3. The fuel filter assembly (100) as claimed in claim 1, wherein the drain passage (304) defines a second opening (312) to allow a flow of water from the inner chamber (306) to the outer chamber (308).
4. The fuel filter assembly (100) as claimed in claim 1, wherein the plunger (316) is activated or deactivated by a solenoid (314) disposed inside the drain passage (304).
5. The fuel filter assembly (100) as claimed in claim 1, wherein density of the
float (324) is lower than density of water and greater than density of fuel, and
wherein the float (324) defines a phase boundary between water and fuel accumulated
in the outer chamber (308).
6. The fuel filter assembly (100) as claimed in claim 4 comprising an electronic
control unit (ECU), wherein the ECU energizes the solenoid (314) based upon the
signals received by the water level sensor (326), and wherein the ECU checks for
faults in a battery, the water level sensor, and the solenoid.
7. The fuel filter assembly (100) as claimed in claim 1, wherein the plunger
(316) remains activated until volume of water contained in the water bowl (114)
drains out.
8. The fuel filter assembly (100) as claimed in claim 1, wherein the plunger (316) is biased away from a cap (206) by a return spring (320) disposed between the plunger (316) and the cap (206).
9. The fuel filter assembly (100) as claimed in claim 1, wherein the water bowl (114) comprises a plurality of oil sorbent pads positioned at the water outlet (318) to collect residual fuel.

10. The fuel filter assembly (100) as claimed in claim 1, wherein the water bowl (114) comprises a mesh having pores of size 30-100 micron positioned at the water outlet (318) to collect residual fuel.