Claims:We claim:

1. A carbon canister assembly (100) for an evaporative emission control (EVAP) system of a vehicle, the carbon canister assembly (100) operatively connected in fluid communication with a purge valve and a fuel tank of the vehicle, the carbon canister assembly (100) comprising:
a case (30) filled up with carbon (40);
a plurality of felts arranged for holding carbon (40) inside the case (30) and providing easy air flow during charging and purging, a plurality of felts including at least one felt (12) arranged at an upper side of the case (30) and at least two felts (14, 16) arranged at a lower side of the case (30);
a grid (20) assembled with the felt (12) of the case (30) for providing support and facilitating proper ventilation;
a cover (10) arranged on the grid (20) for covering the case (30);
a pre-filter (60) arranged at the lower side of the case (30);
a pleated element (55) fitted inside the pre-filter (60) for ensuring clean air entry into during purge;
a pressure sensor (50) arranged at an inlet of the pre-filter (60) using mounting screws (45); and
a pipe (70) operably connected with the pre-filter (60) for air intake from the atmosphere;
wherein, the pressure sensor (50) ensures optimum restriction value for the pleated element (55) and gives service indication of the pre-filter (60) by means selected from a display of a dashboard of the vehicle and an electronic control unit (ECU) of the vehicle.

2. The carbon canister assembly (100) as claimed in claim 1, wherein the plurality of felts (12, 14, 16) includes non-woven felts.

3. The carbon canister assembly (100) as claimed in claim 1, wherein the grid (20) is assembled for holding at least two springs (18) arranged between the cover (10) and the grid (20).

4. The carbon canister assembly (100) as claimed in claim 1, wherein the pleated element (55) is in fluid communication with an inlet of the case (30).

Dated 26th day of February 2020

Madhavi Vajirakar
(Agent for Applicant)
IN/PA-2337 , Description:CARBON CANISTER ASSEMBLY

Field of the invention:

The present invention relates generally to evaporative emission control (EVAP) systems for automobiles, and more particularly, to an automotive carbon canister having a pre-filter embedded with a pressure sensor.

Background of the invention:

The Evaporative Emission Control (EVAP) system is arranged in the fuel system of the vehicle in order to prevent fuel vapors from the fuel tank and the fuel system from escaping into the atmosphere directly. As fuel vapors contain a variety of hydrocarbons that form smog when they react with air and sunlight. The EVAP system consists of a canister that is connected to the fuel tank by a tank vent line. The canister stocks 1-2 pounds of activated charcoal that acts like a sponge by absorbing and storing fuel vapors until the purge valve opens and allows the vacuum of the engine intake to siphon the fuel vapors from the charcoal into the engine intake manifold.

Referring to figure 1, a conventional canister (10) consists of a pipe (1) connected with a case (3). A felt (2) is arranged between the pipe (1) and the case (3). The case (3) consists of a carbon (4) and is covered with a cover (5). In the conventional canister (10) design, a pre filter (not shown) is arranged at an inlet thereof. However, servicing of the pre filter is planned as per predefined service interval. Thus, there is chance of choking the pre filter if it is not serviced at the right time. This leads to poor performance of the carbon canister (10) as foreign particles may enter the canister (10) and affect the performance.

A prior art patent US7562651B2 relates to vapor canister having integrated evaporative emission purge actuation monitoring system having fresh air filter. The vapor canister has a plurality of sidewalls defining a housing with a valve body formed integrally on the housing and a cover mounted to the valve body so as to define a vent chamber between the cover and the valve body. The integrated valve body has a main flow passage and a canister port. An air filter assembly is disposed adjacent to the valve body on the housing and provides fluid communication between the main flow passage and the ambient air. A first one-way umbrella valve mounted to the valve body that is responsive to predetermined positive pressure in the main flow passage to control flow of fluid from a vapor canister to ambient air as well as a second one-way umbrella valve that is responsive to a predetermined negative pressure in the main flow passage to control the flow of ambient air through an air filter assembly.

However, the prior art patent does not disclose about integration of a chock sensor (pressure sensor) which will pass the service indication of the pre-cleaner to dash board or an Electronic control unit (ECU).

Accordingly, there exists a need to provide an improved design of the carbon canister having a pre-filter embedded with a pressure sensor that overcomes the drawbacks of the prior arts.

Objects of the invention:

An object of the present invention is to provide a carbon canister assembly having a pre-filter embedded with a pressure sensor.

Another object of present invention is to provide service indication of the pre-filter.

Yet another object of present invention is to increase performance of the carbon canister assembly.

Summary of the invention:

Accordingly, the present invention provides a carbon canister assembly for an evaporative emission control (EVAP) system of a vehicle. The carbon canister assembly operatively connected in fluid communication with a purge valve and a fuel tank of the vehicle. The carbon canister assembly comprises of a cover, a plurality of felts, a grid, a case, a pre-filter, a pressure sensor and a pipe for air intake. The case is filled up with carbon. The plurality of felts includes at least one felt arranged at an upper side of the case and at least two felts arranged at a lower side of the case for holding carbon granules inside the case. The grid is assembled with the upper felt of the case for providing support and facilitating proper ventilation. The cover is arranged on the grid for covering the case.

The pre-filter is arranged at the lower side of the case. A pleated element is fitted inside the pre-filter for ensuring clean air entry into during purge. The pressure sensor is arranged at an inlet of the pre-filter using mounting screws. The pipe is operably connected with the pre-filter for air intake from the atmosphere. The pressure sensor ensures optimum restriction value for the pleated element. The pressure sensor senses the pressure of the pre-filter and gives service indication of the pre-filter by a display of a dashboard of the vehicle or an electronic control unit (ECU) of the vehicle.

Brief description of the drawings:

Figure 1 shows a conventional canister design, in accordance with the prior art;

Figure 2 shows a cross-sectional front view of a carbon canister assembly, in accordance with the present invention;

Figure 3 shows a cross-sectional perspective view of the carbon canister assembly, in accordance with the present invention;
Figure 4 shows a perspective view of the carbon canister assembly, in accordance with the present invention;

Figure 5 shows an exploded view of the carbon canister assembly, in accordance with the present invention;

Figure 6 shows an exploded view of a pre-filter of the carbon canister assembly, in accordance with the present invention; and

Figure 7 shows air/vapors flow direction in the carbon canister assembly, in accordance with the present invention.

Detailed description of the invention:

The foregoing objects of the present invention are accomplished and the problems and shortcomings associated with the prior art, techniques and approaches are overcome by the present invention as described below in the preferred embodiments.

The present invention provides a carbon canister assembly having a pre-filter embedded with a pressure sensor. The pressure sensor indicates the time to service the pre-filter.

Yet another object of present invention is to increase performance of the carbon canister assembly.

This present invention is illustrated with reference to the accompanying drawings, throughout which reference numbers indicate corresponding parts in the various figures. These reference numbers are shown in bracket in the following description.

Referring to figures 2 to 7, a carbon canister assembly (100) (hereinafter referred as, “the assembly (100)”) for an evaporative emission control (EVAP) system for a vehicle, in accordance with the present invention is shown. The assembly (100) is operably connected with a purge valve (not shown) and a fuel tank (not shown) of the vehicle. The assembly (100) comprises of a cover (10), a plurality of felts, a grid (20), a case (30), a pressure sensor (50), a pre-filter (60) and a pipe (70).

The case (30) is filled up with carbon (40) that is also referred as charcoal. The plurality of felts includes at least one felt (12) arranged at an upper side of the case (30) and at least two felts (14, 16) arranged at a lower side of the case (30) for holding carbon granules inside the case (30). In an embodiment, the felt is used for holding carbon granules without leaking out and providing easy air flow during charging and purging. Specifically, the plurality of felts (12, 14, 16) are non-woven felts are used for upper filters. The grid (20) is assembled with the upper felt (12) of the case (30) for providing support and facilitating proper ventilation. The cover (10) is arranged on the grid (20) for covering the case (30). In the embodiment, the grid (20) is assembled for holding at least two springs (18) arranged between the cover (10) and the grid (20).

The pre-filter (60) is arranged lower side of the case (30). The pleated element (55) is fitted inside the pre-filter (60), wherein the pleated element (55) is in fluid communication with an inlet of the case (30). An integration of the pleated element (55) ensures clean air entry into the case (30) during purge. The pressure sensor (50) is arranged at an inlet (not numbered) of the pre-filter (60) using mounting screws (45). The pipe (70) is operably connected with the pre-filter (60) for air intake from the atmosphere.

Again referring to figures 2 to 7, an operation of the assembly (100) is described herewith. The atmospheric air passing through the air intake pipe (70) chokes the pre-filter (60) over a period of time. The choking of the pre-filter (60) causes lowering the performance of the assembly (100). Referring to figure 7, an air/vapors flow direction in the assembly (100) is shown, wherein ‘A’ indicates air intake flow form the atmosphere inside the assembly (100), ‘B’ indicates flow of fuel vapors from the assembly (100) to an engine cylinder head (not shown) of the vehicle and ‘C’ indicates flow of fuel vapors coming from the fuel tank into the assembly (100). The pressure sensor (50) senses the pressure and gives the service indication to customer by an Electronic Control Unit (ECU) (not shown) or direct display on a dashboard (not shown) of the vehicle. The pressure sensor (50) ensures optimum restriction value for the pleated element (55). If the restriction reaches a particular value, the pleated element (55) has to be replaced. The pre-filter (60) will be cleaned or replaced based on output of the pressure sensor (60) indicated the dashboard.

Advantages of the present invention:

1. The pressure sensor (50) is integrated in the pre-filter housing (60), hence no separate additional space is needed for installation of the pressure sensor (50).
2. The external pre-filter (60) can be cleaned or replaced within a time.
3. The assembly (100) is protected from external impurities. Water/Moister air entry is restricted.
4. The efficiency of the assembly (100) is increased.

The foregoing descriptions of specific embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the present invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the present invention and its practical application, to thereby enable others skilled in the art to best utilize the present invention and various embodiments with various modifications as are suited to the particular use contemplated. It is understood that various omission and substitutions of equivalents are contemplated as circumstance may suggest or render expedient, but such are intended to cover the application or implementation without departing from the scope of the present invention.