Patent Publication Number: US-7594500-B2

Title: Air control module

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application Ser. No. 60/759,354, filed Jan. 17, 2006, which is hereby fully incorporated by reference. 
    
    
     FIELD 
     The present disclosure generally pertains to evaporative emissions control systems. 
     BACKGROUND 
     Conventional motor vehicles, due to increased emission standards, typically include a fuel vapor recovery system. The fuel vapor recovery system includes a vapor or purge canister for receiving fuel vapors generated in the fuel tank. A fuel vapor absorbent, typically activated charcoal, located in the vapor canister retains the fuel vapor when the vapors are displaced from the fuel tank during refilling. During operation of the engine, the fuel vapor contained in the vapor canister is purged by drawing fresh air through the canister and into the intake manifold of the engine. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Features and advantages of a system and method consistent with the present disclosure are set forth by description of embodiments consistent therewith, which description should be considered in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a schematic diagram of an embodiment of an evaporative emissions control system consistent with the present disclosure; 
         FIG. 2  is a schematic diagram of an embodiment of an evaporative emissions control system consistent with the present disclosure during normal engine operation; 
         FIG. 3  is a schematic diagram of another embodiment of an evaporative emissions control system consistent with the present disclosure; 
         FIG. 4  is a schematic diagram of an embodiment of an evaporative emissions control system consistent with the present disclosure while the engine is not operating; and 
         FIG. 5  is a schematic diagram of another embodiment of an evaporative emissions control system consistent with the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , an embodiment of an evaporative emissions system  100  is schematically illustrated. As shown, the evaporative emissions system  100  may control the release of fuel vapors from the fuel tank  102  during refueling, during elevated temperatures, etc., in which fuel vapors from the fuel tank  102  may be displaced from, e.g. due to being pressurized within, the fuel tank  102  by liquid fuel being delivered to the fuel tank  102 . 
     As shown, fuel vapors from the fuel tank  102  may travel to the evaporative emissions canister  104 , which may serve as a storage device for fuel vapors. The evaporative emissions canister  104  may contain a medium, such as activated carbon, which may collect the fuel vapors to prevent the vapor from being emitted into the atmosphere. During normal operation of the vehicle, the fuel vapors collected by the evaporative emissions canister  104  may be released to the engine and may be consumed by the engine  106 . 
     As shown, the evaporative emissions canister  104  may be coupled to the fuel tank  102  and to the engine  106  by an air control module  108 . The air control module  108  may include a canister purge valve  110 , a vapor blocking valve  112 , and a canister vent valve  114  at least partially contained within a housing  109  of the air control module  108 . The valves  110 ,  112  and  114  may take any known valve configuration. In one embodiment, for example, the valves may be solenoid-type valves configured for opening/closing in response to an electrical input. The air control module  108  may also include or may be coupled to an air filter  116  for removing any particulate or liquid, e.g., moisture, contamination from an air intake provided by an atmospheric vent  118 . 
     According to one aspect, the air control module  108  may be provided as a single unit, which may communicate with the evaporative emissions canister  104  via one or more corresponding ports  120 ,  122 ,  124 . While three ports are shown, a greater or fewer number of ports may be utilized depending upon the exact configuration of the canister  104  and of the various valves  110 ,  112 ,  114  of the air control module  108 . According to a related aspect, the air control module  108  may be mechanically coupled to the evaporative emissions canister  104  by snap latches. Other fastening arrangements, such as screws, clamps, interacting integral features, etc., may also be suitably employed for coupling the air control module and the evaporative emissions canister. According to yet another aspect, the air control module  108  may include a single connector  130 , which may be integral to the air control module  108 , for controlling all of the valves  110 ,  112 ,  114 . The single connector  130  may couple the air control module  108  to an engine control module, or similar control system  207 . 
     The engine control module or similar control system  207  may transmit and/or receive one or more signals to the air control module  108  resulting in the opening and/or closing of the valves  110 ,  112 ,  114 . The signals may include commands or may include data which may be interpreted by the air control module  108 . In either case, the valves  110 ,  112 ,  114  may be fully opened/closed or partially opened/closed. Alternatively, one or more of the valves  110 ,  112 ,  114  may be provided with an independent connector for controlling the valve. 
     According to one embodiment, one or more of the valves  110 ,  112 ,  114  may be normally open (i.e., the valve  110 ,  112 , and/or  114  may be in an open position unless otherwise instructed to close). In this case, the valve  110 ,  112 ,  114  is open unless the engine control module, or similar control system  207  instructs the valve  110 ,  112 ,  114  to close. For example, the valve  110 ,  112 ,  114  may be fail-safe open. According to another embodiment, one or more of the valves  110 ,  112 ,  114  may be normally closed (i.e., the valve  110 ,  112 , and/or  114  may be in a closed position unless otherwise instructed to open). In this case, the valve  110 ,  112 ,  114  is closed unless the engine control module, or similar control system  207  instructs the valve  110 ,  112 ,  114  to open. For example, the valve  110 ,  112 , and/or  114  may be fail-safe closed. Alternatively, one or more of the valves  110 ,  112 ,  114  may not be biased towards either the open or closed position. 
     The canister purge valve  110  of the air control module  108  may control the passage of fuel vapor from the evaporative emissions canister  104  through the port  120  to the engine  106  through a port  132  in the housing  109  of the air control module  108 . For example, during normal engine operating conditions as shown in  FIG. 2 , the fuel vapors stored in the evaporative emissions canister  104  may be provided to the engine  106 . The engine control module, or similar control system  207  may transmit a signal to the air control module  108  resulting in the canister purge valve  110  opening during normal operating conditions to allow the passage of fuel vapor from the evaporative emissions canister  104  to the engine  106 . Vacuum from the intake manifold may draw the fuel vapor from the evaporative emissions canister  104  to the engine  106 , where the fuel vapor may mix with air in the intake manifold to be consumed by the engine  106 . 
     The canister vent valve  114  may be normally open to allow the flow of air into the evaporative emissions canister  104  through the atmospheric vent  118 . During normal engine operating conditions as shown in  FIG. 2 , the engine control module, or similar control system  207  may additionally transmit a signal to the air control module  108  resulting in the canister vent valve  114  opening. As a result, air drawn into the evaporative emissions canister  104  may flow through the canister medium and canister purge valve  110  (when it is open) allowing the fuel vapor stored in the evaporative emissions canister  104  to be delivered to the engine  106 . The air filter  116  may remove at least a portion of any particulate, liquid, e.g., moisture, etc., contamination in the air passing from the atmospheric vent  118 , through the canister vent valve  114 , and into the evaporative emissions canister  104 . 
     In addition to controlling air flow into the evaporative emissions canister  104  during normal engine operating conditions, the canister vent valve  114  may control the flow of air from the evaporative emissions canister  104 . For example, during fueling or elevated temperatures as shown in  FIG. 3 , fuel vapor may flow from the fuel tank  102  and into the evaporative emissions canister  104 , as a result of the increased pressure within the fuel tank  102 . After at least a portion of fuel vapor has been extracted by the canister medium, the air may flow from the evaporative emissions canister  104  and out through the canister vent valve  114 , allowing the pressure in the fuel tank  102  to be reduced. The canister vent valve  114  may be closed during diagnostic testing of the evaporative emissions system  100 , etc. 
     The vapor blocking valve  112  may be disposed between the fuel tank  102  and the evaporative emissions canister  104 . The vapor blocking valve  112  may control the flow of vapors, through a port  134  in the housing  109  of the air control module  108 , between the fuel tank  102  and the remainder of the evaporative emissions system  100 . For example, the vapor blocking valve  112  may allow fuel vapor to travel from the fuel tank to the evaporative emissions canister  104 , e.g., as a result of an increase in pressure within the fuel tank, e.g., during refueling or during elevated temperatures as shown in  FIG. 3 . The vapor blocking valve  112  may, however prevent the flow of fuel vapor from the fuel tank  102  and to the engine  106  as a result of intake manifold vacuum, which would normally draw fuel vapor from the evaporative emissions canister  104  through the canister purge valve  110  as shown in  FIG. 2 . For example, the vapor blocking valve  112  may be controlled to be closed when the canister vent valve  110  is open. It should be appreciated, however that various additional and/or alternative control schemes may suitably be employed herein. 
     Referring to  FIG. 4 , another embodiment of an evaporative emissions system  200  is shown. As illustrated, the evaporative emissions system  200  may include an air control module  108  for controlling the flow of fuel vapor from a fuel tank  202  into an evaporative emissions canister  204  and from the evaporative emissions canister  204  to an engine  206 , e.g., to an intake manifold. Additionally, the air control module  108  may control the flow of air into and out of the evaporative emissions canister  204 . The air control module  108  may include a plurality of valves for controlling the flow of fuel vapor and air through the evaporative emissions canister  204 . For example, the air control module may include a canister vent valve  114 , a vapor blocking valve  112 , and a purge valve  110 . The valves of the air control module  108  may be controlled by an engine management controller  207 , and may be coupled to the engine management controller  207  via a single integral connector on the air control module  108 . The air control module  108  may also include a fresh air filter for removing at least a portion of any particulate or liquid contaminants from air admitted into the evaporative emissions canister  204 . The air control module  108  may communicate with the evaporative emissions canister  204  through connecting ports, and may be mechanically coupled to the evaporative emissions canister  204  by snap latches. 
     Turning to  FIG. 5 , yet another embodiment of an evaporative emissions control system  300  is depicted. Similar to the preceding embodiments, the evaporative emissions control system  300  may include an evaporative emissions canister  304  for collecting fuel vapor from a fuel tank  302 . A vapor isolation valve  312  may be provided between the fuel tank  302  and the evaporative emissions canister  304  for controlling the flow of fuel vapor from the fuel tank  302  to the evaporative emissions canister  304 . The vapor isolation valve  312  may also prevent fuel vapor from being drawn from the fuel tank  302  and through the evaporative emissions canister  304  by the vacuum of the intake manifold when the canister purge valve  310  is open. As with previous embodiments, the canister purge valve  310  may allow fuel vapor collected by the evaporative emissions canister  304  to be drawn in to the engine, as by the vacuum of the intake manifold. Additionally the system  300  may include a canister vent valve  314  for controlling the flow of air into and out of the evaporative emissions canister  304 . 
     According to one aspect of the present disclosure, there is thus provided an air control module including: a canister purge valve; a vapor blocking valve; a canister vent valve; and a housing, wherein at least a portion of the canister purge valve, the vapor blocking valve, and the canister vent valve are disposed within the housing. 
     According to another aspect of the disclosure there is provided an evaporative emission system including: a fuel tank; an engine; an evaporation canister; and air control module including: a canister vent valve fluidly coupled to an atmospheric vent and the evaporation canister; a vapor blocking valve fluidly coupled to the fuel tank and the evaporation canister; a canister vent valve fluidly coupled to the engine and the evaporation canister; and a housing, wherein at least a portion of the canister purge valve, the vapor blocking valve, and the canister vent valve are disposed within the housing. 
     According to yet another aspect of the disclosure there is provided a method of fabricating an evaporative emission system including: providing an air control module including a canister purge valve, a vapor blocking valve, a canister vent valve, and a housing, wherein at least a portion of the canister purge valve, the vapor blocking valve, and the canister vent valve are disposed within the housing; fluidly coupling the canister vent valve to an atmospheric vent and an evaporation canister; fluidly coupling the vapor blocking valve to a fuel tank and the evaporation canister; and fluidly coupling the canister purge valve to an engine and the evaporation canister. 
     The various features and aspects of the illustrated embodiments of a filter system herein are set forth for the purpose of illustration, and not of limitation. Such features and aspects are susceptible to combination with the features and aspects of the various other embodiments herein. Furthermore, the embodiment described and illustrated are susceptible to variation and modification without departing from the present claims.