Patent Application
20080223343
The present disclosure relates to emission control devices for vehicles. More particularly, the present invention relates to a filter box with an integrated vent solenoid to connect to the atmospheric port of an automotive emission storage canister.
The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Canisters for storing emissions are provided on automotive vehicles to prevent the discharge of fuel vapors outside vehicles during refueling and normal operation. Often referred to as onboard refueling vapor recovery (ORVR), the typical canister contains activated carbon and is mounted within a vehicle in communication, via a first or vapor inlet port, with the headspace in the fuel tank; via a second or vapor outlet port, with a vacuum source in the engine intake manifold; and via a third or vent port, with the atmosphere outside the vehicle. During refueling, the fill pipe is sealed against vapor leakage, either by a flexible gasket surrounding the fill nozzle or by a liquid seal in the fill pipe. As the tank is filled, air and vapors in the headspace above the fuel are forced through the vapor inlet port into the canister. The vapors are adsorbed onto the charcoal bed, and the air is discharged through the vent port. During subsequent operation of the vehicle, the engine vacuum draws air through the vent port, gradually purging the adsorbed vapors via the vapor outlet port into the engine's combustion flow and preparing the canister for the next refueling. Air also flows back through the vent port into the fuel tank as needed to replace fuel being consumed by the engine.
The air vent port is normally open during periods of non-operation of the vehicle. Fuel tank vapors must be adsorbed by the canister before reaching the vent port. This function is known in the art as diurnal adsorption. Such diurnally adsorbed fuel is also desorbed and conveyed by vacuum to the engine upon startup.
Federal regulations require that each vehicle be equipped to conduct an onboard diagnostic (OBD) leak test of the evaporative emissions system. Several manufacturers use a vacuum decay OBD which requires apparatus for closing off the vapor outlet and vent ports, the vapor inlet port being effectively sealed during test by the fuel tank cap.
Typically, an ORVR canister is mounted immediately adjacent the fuel tank to minimize vapor flow restriction into the canister. Since the fuel tank commonly is located near the rear of the vehicle and the engine at the front, a relatively long hose run is required to connect the canister to the engine intake. A first electric solenoid valve at the canister can close the canister vent port, and a second solenoid valve at the engine can close the vapor outlet line. To test the system for leaks, first the vent port is closed, exposing the system to full engine vacuum, then the outlet line is closed. The OBD system monitors the rate of decay of the captured vacuum.
Mounting the canister at the rear of the vehicle exposes the vent port to dust and debris which, if allowed to enter the canister, can foul the vent solenoid and internal passages, gradually clogging the solenoid valve and the canister and causing failure of the seal test. Entry of dust and debris can also cause operational problems with refueling of the vehicle, including failure to fill properly and premature shutoffs of the refueling nozzle. To prevent such entry, U.S. Pat. No. 5,878,729 issued Mar. 9, 1999 to Covert et al. ('729) and incorporated herein by reference, discloses a canister providing two separate vent ports, an outlet vent port with a check valve for releasing fuel tank air during refueling, and an inlet vent port connected to the downstream side of the engine air filter. An additional check valve is disposed between the inlet vent port and the engine to prevent vapors flowing into the air cleaner during refueling and causing an over rich fuel/air mixture being fed to the engine at start up.
U.S. Pat. No. 6,390,073 issued May 21, 2002 to Meiller et al. ('073) discloses an onboard vapor recovery canister which utilizes a solenoid valve in association with a filter means, but requires attached to the fuel system as a single assembly. Furthermore, the '073 patent operates only with a foam filter and carbon absorption bed. Eventually, a higher pressure drop increase can result after prolonged use of the canister, which can often cause early shut off of a refueling pump nozzle due to backed up fuel vapors in the fuel tank.
The present invention overcomes the above short comings in the art, comprising of a filter box having an integrated vent solenoid to connect to the atmospheric port of an automotive emission storage canister in relation to the fuel tank of the vehicle, used to recapture fuel vapor before it is released into the atmosphere. The filter box with integrated vent solenoid is sealed to the atmospheric port of the canister, and consists of a filter housing with an internal feature to house and retain a vent solenoid, an optional dust trap, an optional foam filter to protect the vent solenoid and the canister against dust, and a filter cap to retain the filter foam. A closed cell foam or rubber O-ring provides a sealing between the filter cap and the filter housing. A further sealing means provides a leak tight seal between the filter box and the canister.
It is a further object of the present invention to provide a filter box for use in conjunction with a canister as herein described which is economical to manufacture.
Another object of the present invention is to provide a filter box which provides a universal fit to a plurality of canisters equipped on various vehicles.
Another object of the present invention is to provide a filter box which may optionally be mounted remotely from a canister, having a sealed connection thereto via tube or conduit.
A further object of the present invention is to provide a filter box having a labyrinth interior portion which assists in separating the dust from the gas flow. The filter box may be used as both a labyrinth filter only, or in combination with a foam filter, leading to lower pressure drop increase over time, thereby preventing early shut off of the refueling nozzle during refueling of the fuel tank.
Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.
The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.
Referring now to the figures, in particular
The filter box 10 with integrated vent solenoid 20 comprises a main housing 14 and is sealingly attached to the atmospheric port of the canister 30 through outlet 18 as part of the evaporative diagnostic known as OBD-II testing. The electrical operated valve seals the fuel tank during the OBD-II testing to check for possible leaks in the complete fuel system. To protect the vent solenoid and the canister against dust, especially during the purge process, the vent solenoid 20 is integrated into the filter box 10. A filter cap 15 is sealingly attached to the opposite end of housing 14 and comprises an atmospheric port 16 therein.
Referring now to
The optional filter foam pad 22 and sealing means 23 are received on the opposite end of the housing 14 from the outlet 18, and are retained in place by filter box cap 15 which is detachably attachable to the housing. The filter box cap 15 as stated above comprises a series of integrated walls 21 which provide a labyrinth-type filtering system for the air which is received through the atmospheric port 16 of the cap 15.
Lastly,
The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.
