Flow sensor for evaporative control system

• US 5,253,629 A
• Filed: 02/03/1992
• Issued: 10/19/1993
• Est. Priority Date: 02/03/1992
• Status: Expired due to Term

• Current Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Original Assignee: General Motors Corporation (Motors Liquidation Co. GUC Trust)
• Inventors: Haskew, Harold M., Muller-Girard, Otto Jr., Meyer, Karen M., Gifford, William E., Fornuto, Joseph
• Primary Examiner(s): MILLER, CARL STUART
• Application Number:
  US07/829,829
• Time in Patent Office: 624 Days
• Field of Search: 123/198 D, 123/518, 123/519, 123/520, 123/521, 123/516
• US Class Current: 123/519
• CPC Class Codes: F02M 25/0809 Judging failure of purge control system

Abstract

A device for detecting a malfunction of the evaporative control system comprises a two-way flow device in the atmospheric air vent of the evaporative canister with a sensor to detect whether fluid is flowing through the canister during selected operating conditions.

Claims

1. In a fuel evaporative control system having a canister for adsorbing fuel vapor evaporated from a fuel tank, said canister having an opening to the fuel tank, an opening to the atmosphere, and an opening to a vacuum source for an engine, the improvement comprising a flow device for detecting a malfunction of said fuel evaporative control system comprising:

a housing having two valve chambers, located in the opening from the canister to atmosphere, and having two apertures for flow into and out of said valve chambers,

one of said apertures opening to atmosphere, and the second of said apertures opening to the canister,

and said valve chambers each having a check valve comprising a valve seat, a valve member engageable with the valve seat, and a valve spring urging the valve member against the valve seat to inhibit flow through the valve chamber, wherein the first valve member opens in response to pressure conditions in said second aperture to permit fluid flow from the fuel tank through the canister and the first valve chamber, and the second valve member opens in response to vacuum conditions in said second aperture to permit flow of air through the second valve chamber and canister, and wherein said flow device includes a means to detect movement of at least one of said valve members.

2. In a fuel evaporative control system having a canister for adsorbing fuel vapor evaporated from a fuel tank, said canister having an opening to the fuel tank, an opening to the atmosphere, and an opening to a vacuum source for an engine, the improvement comprising a flow device for detecting a malfunction of said fuel evaporative control system comprising:

a housing having two valve chambers, located in the opening from the canister to atmosphere, and having two apertures for flow into and out of said valve chambers,

one of said apertures opening to atmosphere, and the second of said apertures opening to the canister,

and said valve chambers being adjacent to each other in longitudinal passages, said housing also having transverse passages that communicate with upper and lower ends of the longitudinal passages, and the upper transverse passage also communicating with said aperture opening to the canister and the lower transverse passage communicating with said aperture opening to the atmosphere, and

each valve chamber having a check valve comprising a valve seat, a valve member engageable with the valve seat, and a valve spring urging the valve member against the valve seat to inhibit flow through the valve chamber, wherein the first valve member opens in response to pressure conditions in said second aperture to permit fluid flow from the fuel tank through the canister and the first valve chamber, and the second valve member opens in response to vacuum conditions in said second aperture to permit flow of air through the second valve chamber and canister, and wherein said flow device includes a means to detect movement of at least one of said valve members.

3. In a fuel evaporative control system having a canister for adsorbing fuel vapor evaporated from a fuel tank, said canister having an opening to the fuel tank, an opening to the atmosphere, and an opening to a vacuum source for an engine, the improvement comprising a flow device for detecting a malfunction of said fuel evaporative control system comprising:

a housing having two valve chambers, located in the opening from the canister to atmosphere, and having two apertures for flow into and out of said valve chambers,

one of said apertures opening to atmosphere, and the second of said apertures opening to the canister,

and said valve chambers being adjacent to each other in longitudinal passages said housing having transverse passages that communicate with upper and lower ends of the longitudinal passages, and the upper transverse passage also communicating with said aperture opening to the canister and the lower transverse passage communicating with said aperture opening to the atmosphere, and

each valve chamber having a check valve comprising a valve seat, a valve member engageable with the valve seat, a valve spring urging the valve member against the valve seat to inhibit flow through the valve chamber, and a stop member against which the first valve member abuts when in the open position in response to pressure conditions in said second aperture thereby permitting fluid from the fuel tank to flow through the canister and around the first valve member, and a stop member against which the second valve member abuts when in the open position in response to vacuum conditions in said second aperture thereby permitting air flow from the atmosphere to flow around the second valve member and through the canister, and wherein said flow device includes means to detect movement of said valve members.

4. In a fuel evaporative control system having a canister for adsorbing fuel vapor evaporated from a fuel tank, said canister having an opening to the fuel tank, an opening to the atmosphere, and an opening to a vacuum source for an engine, the improvement comprising a flow device for detecting a malfunction of said fuel evaporative control system comprising:

a housing having two valve chambers, located in the opening from the canister to atmosphere, and having two apertures for flow into and out of said valve chambers,

one of said apertures opening to atmosphere, and the second of said apertures opening to the canister,

said valve chambers each having a check valve comprising a valve seat, a valve member engageable with the valve seat, and a valve spring urging the valve member against the valve seat to inhibit flow through the valve chamber, wherein the first valve member opens in response to pressure conditions in said second aperture to permit fluid flow from the fuel tank through the canister and the first valve chamber, and the second valve member opens in response to vacuum conditions in said second aperture to permit flow of air through the second valve chamber and canister, and wherein said second valve member is guided by a shaft that communicates with a sensor that can detect movement of said shaft and thereby detect a malfunction of the fuel evaporative control system

5. In a fuel evaporative control system having a canister for adsorbing fuel vapor evaporated from a fuel tank, said canister having an opening to the fuel tank, an opening to the atmosphere, and an opening to a vacuum source for an engine, the improvement comprising a flow device for detecting a malfunction of said fuel evaporative control system comprising:

a housing having two valve chambers, located in the opening from the canister to atmosphere, and having two apertures for flow into and out of said valve chambers,

one of said apertures opening to atmosphere, and the second of said apertures opening to the canister,

said valve chambers each having a check valve comprising a valve seat, a valve member engageable with the valve seat, and a valve spring urging the valve member against the valve seat to inhibit flow through the valve chamber, wherein the first valve member opens in response to pressure conditions in said second aperture to permit fluid flow from the fuel tank through the canister and the first valve chamber, wherein said first valve member is guided by a steel shaft which communicates with a magnetic proximity sensor that can detect movement of said shaft, wherein the second valve member opens in response to vacuum conditions in said second aperture to permit flow of air through the second valve chamber and canister, and wherein said second valve member is guided by a second steel shaft which communicates with a magnetic proximity sensor that can detect movement of said second shaft, whereby said flow device detects malfunctions of the fuel evaporative control system.

6. In a fuel evaporative control system having a canister for adsorbing fuel vapor evaporated from a fuel tank, said canister having an opening, to the fuel tank, an opening to the atmosphere, and an opening to a vacuum source for an engine, the improvement comprising a flow device for detecting a malfunction of said fuel evaporative control system comprising:

a housing having two valve chambers, located in the opening from the canister to atmosphere, and having two apertures for flow into and out of said valve chambers,

one of said apertures opening to atmosphere, and the second of said apertures opening to the canister,

said valve chambers being adjacent to each other in longitudinal passages, said housing having transverse passages that communicate with upper and lower longitudinal passages, and the upper transverse passage also communicating with said aperture opening to the canister and lower transverse passage communicating with said aperture opening to the atmosphere, and

each valve chamber having a check valve comprising a valve seat, a valve member engageable with the valve seat, and a valve spring urging the valve member against the valve seat to inhibit air flow through the valve chamber, and a stop member against which the first valve member abuts when in the open position in response to pressure conditions in said second aperture thereby permitting fluid from the fuel tank to flow through the canister and around the first valve member, and a stop member against which the second valve member abuts when in the open position in response to vacuum conditions in said second aperture thereby permitting air flow from the atmosphere to flow around the second valve member and canister, and wherein said second valve member is guided by a steel shaft that communicates with a magnetic proximity sensor that can detect movement of the shaft and thereby detect a malfunction of the fuel evaporative control system.

7. In a fuel evaporative control system having a canister for adsorbing fuel vapor evaporated from a fuel tank, said canister having an opening to the fuel tank, an opening to the atmosphere, and an opening to a vacuum source for an engine, the improvement comprising a flow device for detecting a malfunction of said fuel evaporative control system comprising:

a housing having two valve chambers, located in the opening from the canister to atmosphere, and having two apertures for flow into and out of said valve chambers,

one of said apertures opening to atmosphere, and the second of said apertures opening to the canister,

said valve chambers being adjacent to each other in longitudinal passages, said housing having transverse passages that communicate with upper and lower longitudinal passages, and the upper transverse passage also communicating with said aperture opening to the canister and lower transverse passage communicating with said aperture opening to the atmosphere, and

each valve chamber having a check valve comprising a valve seat, a valve member engageable with the valve seat, and a valve spring urging the valve member against the valve seat to inhibit air flow through the valve chamber, and a stop member against which the first valve member abuts when in the open position in response to pressure conditions in said second aperture thereby permitting fluid from the fuel tank to flow through the canister and around the first valve member, and wherein said first valve member is guided by a steel shaft that communicates with a magnetic proximity sensor that can detect movement of the shaft, and a stop member against which the second valve member abuts when in the open position in response to vacuum conditions in said second aperture thereby permitting air flow from the atmosphere to flow around the second valve member and through the canister, and wherein said second valve member is guided by a second steel shaft that communicates with a magnetic proximity sensor that can detect movement of the second shaft, whereby the flow device detects malfunctions of the fuel evaporative control system and transmits that information to a control system.

8. In a fuel evaporative control system having a canister for adsorbing fuel vapor evaporated from a fuel tank, said canister having an opening to the fuel tank, an opening to the atmosphere, and an opening to a vacuum source for an engine, the improvement comprising a flow device for detecting a malfunction of said fuel evaporative control system comprising:

a housing located in the opening from the canister to atmosphere, and having a valve chamber and two apertures for flow into and out of said valve chamber, the first of said apertures opening to atmosphere, and the second of said apertures opening to the canister,

said valve chamber having a valve member, said valve member being sensitive to change in pressure within the two apertures, whereby said valve member moves in response to a difference in pressure conditions between said second aperture and said first aperture to permit air flow through said valve chamber, and wherein said flow device includes means to detect movement of said valve member, whereby a malfunction of said fuel evaporative control system is detected when no movement of said valve member is detected.