Evaporative emissions control system including a charcoal canister for small internal combustion engines

• US 7,267,112 B2
• Filed: 01/14/2005
• Issued: 09/11/2007
• Est. Priority Date: 02/02/2004
• Status: Expired due to Fees

• Current Assignee: Certified Parts Corporation
• Original Assignee: Tecumseh Products Company
• Inventors: Carpenter, Todd L., Hintz, Gregory C., Kirk, J. David, Donahue, Ronald J.
• Primary Examiner(s): MOULIS, THOMAS N
• Application Number:
  US11/035,655
• Publication Number:
  US 20050178368A1
• Time in Patent Office: 970 Days
• Field of Search: 123/516, 123/517, 123/518, 123/519, 123/520
• US Class Current: 123/518
• CPC Class Codes: B60K 15/03504 adapted to avoid loss of fuel or fuel vapour, e.g. with vapour recovery systems
• CPC Class Codes: B60K 2015/03557 comprising elements of the venting device integrated in the fuel tank, e.g. vapor recovery means
• CPC Class Codes: F02B 63/02 for hand-held tools
• CPC Class Codes: F02M 25/08 adding fuel vapours drawn from engine fuel reservoir electrical control of purge system F02D41/003
• CPC Class Codes: F02M 25/0854 Details of the absorption canister
• CPC Class Codes: F02M 25/089 Layout of the fuel vapour installation
• CPC Class Codes: F02M 35/02 Air cleaners
• CPC Class Codes: F02M 35/10019 Means upstream of the fuel injection system, carburettor or plenum chamber F02M35/10013 takes precedence
• CPC Class Codes: F02M 35/1017 Small engines, e.g. for handheld tools, or model engines; Single cylinder engines
• CPC Class Codes: F02M 35/10196 Carburetted engines
• CPC Class Codes: F02M 35/10222 Exhaust gas recirculation [EGR]; Positive crankcase ventilation [PCV]; Additional air admission, lubricant or fuel vapour admission

Abstract

An evaporative emissions control system for small internal combustion engines, including a charcoal canister which is in fluid communication with the air space above the liquid fuel within the carburetor of the engine and the air space above the liquid fuel within the fuel tank of the engine. The charcoal canister contains charcoal media, and when the engine is not running, fuel vapors from the carburetor and the fuel tank migrate to, and are trapped within, the charcoal media of the charcoal canister. The charcoal canister may comprise a separate component, or may be integrally formed with an engine component such as the air cleaner, the carburetor, or the body of the fuel tank, for example. During running of the engine, vacuum within the carburetor induces a flow of atmospheric air through the charcoal canister to purge the collected fuel vapors from the charcoal media, and the fuel vapors pass into the engine for consumption. In another embodiment, an evaporative emissions control system including a charcoal canister is provided for an engine which includes a fuel injection system.

Claims

1. An internal combustion engine, comprising:

a carburetor having an intake air passage, and a fuel chamber in fluid communication with said passage, said chamber containing a volume of liquid fuel and an air space;

a fuel tank in fluid communication with said fuel chamber, said fuel tank containing a volume of liquid fuel and an air space; and

a fuel vapor control device including a housing containing fuel vapor absorbent media and having a substantially elongate profile along an axis, said housing defining first and second ends and a central portion therebetween, said carburetor passage in fluid communication with one of said first and second ends and the other of said first and second ends in fluid communication with the atmosphere, at least one of said carburetor air space and said fuel tank air space in fluid communication with said central portion of said housing at a location on said housing disposed axially in between said first and second ends;

whereby fuel vapors collect within said fuel vapor absorbent media initially within said central portion of said housing and thereafter outwardly toward said first and second ends, and passage of air through said carburetor passage induces a flow of air from the atmosphere axially through said housing to said carburetor passage to purge fuel vapors from said housing.

2. The internal combustion engine of claim 1, wherein said fuel vapor absorbent media is charcoal media.

3. The internal combustion engine of claim 1, wherein said housing includes a length between said first and second ends and a width, said length at least twice said width.

4. The internal combustion engine of claim 1, wherein said housing is in fluid communication with said carburetor air space and with said fuel tank air space.

5. The internal combustion engine of claim 1, further comprising an air cleaner in airflow communication with said carburetor passage, said housing integrally formed with said air cleaner.

6. The internal combustion engine of claim 1, wherein said fuel tank includes a body, said housing integrally formed with said fuel tank body.

7. An internal combustion engine operable at low and high speeds, comprising:

a carburetor, comprising;

a passage through which engine intake air is drawn, said passage having an inlet and an outlet;

a throttle valve disposed within said passage, said throttle valve movable between a substantially closed position corresponding to low engine speeds and a substantially open position corresponding to high engine speeds; and

a fuel chamber in fluid communication with said passage, said fuel chamber containing a volume of liquid fuel and an air space;

a fuel tank in fluid communication with said fuel chamber, said fuel tank containing a volume of liquid fuel and an air space; and

a fuel vapor control device including a housing containing fuel vapor absorbent media, said housing in fluid communication with at least one of said carburetor air space and said fuel tank air space, and in fluid communication with said carburetor passage at a first location proximate said throttle valve and at a second location proximate said inlet;

whereby fuel vapors collect within said fuel vapor absorbent media of said housing, and at low engine speeds, airflow through said carburetor passage with substantial closure of said throttle valve induces purging of fuel vapors from said housing in a direction from said second location to said first location, and at high engine speeds, airflow through said carburetor passage with substantial opening of said throttle valve induces purging of fuel vapors from said housing in a direction from said first location to said second location.

8. The internal combustion engine of claim 7, wherein said fuel vapor absorbent media is charcoal media.

9. The internal combustion engine of claim 7, wherein said housing is in fluid communication with said carburetor air space and with said fuel tank air space.

10. The internal combustion engine of claim 7, further comprising an air cleaner in airflow communication with said carburetor passage, said housing integrally formed with said air cleaner.

11. The internal combustion engine of claim 7, wherein said fuel tank includes a body, said housing integrally formed with said fuel tank body.

12. The internal combustion engine of claim 7, wherein said housing is elongate and includes first and second ends, said first end in fluid communication with said carburetor at said first location and said second end in fluid communication with said carburetor at said second location.

13. The internal combustion engine of claim 12, wherein said housing includes a length between said first and second ends and a width, said length at least twice said width.

14. The internal combustion engine of claim 12, wherein said housing includes a central portion between said first and second ends, said central portion in fluid communication with at least one of said carburetor air space and said fuel tank air space.

15. An internal combustion engine, comprising:

a carburetor having an intake air passage, and a fuel chamber in fluid communication with said passage, said chamber containing a volume of liquid fuel and an air space;

a fuel tank in fluid communication with said fuel chamber, said fuel tank containing a volume of liquid fuel and an air space; and

a fuel tank cap attached to said fuel tank and containing fuel vapor absorbent media, said fuel tank cap in fluid communication with said carburetor passage, the atmosphere, and with said fuel tank air space and said carburetor air space;

whereby fuel vapors collect within said fuel vapor absorbent media, and passage of air through said carburetor passage induces a flow of air from the atmosphere through said fuel tank cap to said carburetor passage to purge fuel vapors from said fuel tank cap.

16. The internal combustion engine of claim 15, wherein said fuel vapor absorbent media is charcoal media.

17. The internal combustion engine of claim 15, wherein said fuel tank cap includes a check valve therein to allow one-way flow of air from the atmosphere into said fuel tank cap.

18. An internal combustion engine, comprising:

a carburetor having an intake air passage, and a fuel chamber in fluid communication with said passage, said chamber containing a volume of liquid fuel and an air space;

a fuel tank in fluid communication with said fuel chamber, said fuel tank containing a volume of liquid fuel and an air space; and

a fuel vapor control device including a housing containing fuel vapor absorbent media, said carburetor air space and said fuel tank air space in fluid communication with said housing, said carburetor passage in fluid communication with said housing and said housing further in fluid communication with the atmosphere; and

a gravity-responsive valve disposed between said fuel tank air space and said fuel vapor control device;

whereby fuel vapors collect within said fuel vapor absorbent media, and passage of air through said carburetor passage induces a flow of air from the atmosphere through said housing to said carburetor passage to purge fuel vapors from said housing.

19. The internal combustion engine of claim 18, wherein said gravity-responsive valve includes a valve body, said valve normally open when said valve body is disposed in a substantially vertical position, said valve closing when said valve body is rotated toward a substantially horizontal position.

20. An internal combustion engine, comprising:

a fuel tank including a filler neck, said fuel tank containing a volume of liquid fuel and an air space; and

a fuel tank cap attached to said filler neck of said fuel tank and containing fuel vapor absorbent media, said fuel tank cap in fluid communication with said fuel tank and with the atmosphere, a portion of said fuel tank cap projecting into said filler neck and including liquid fuel blocking structure;

whereby fuel vapors collect within said fuel vapor absorbent media and liquid fuel from said fuel tank is blocked from contacting said fuel vapor absorbent media by said liquid fuel blocking structure.

21. The internal combustion engine of claim 20, wherein said liquid fuel blocking structure of said fuel tank cap portion includes an anti-rollover valve.