Automotive fuel filler pipe cap detection system

• US 5,451,927 A
• Filed: 08/16/1993
• Issued: 09/19/1995
• Est. Priority Date: 08/16/1993
• Status: Expired due to Fees

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Motor Company
• Inventors: Thompson, Robert H.
• Primary Examiner(s): Swarthout, Brent
• Application Number:
  US08/106,674
• Time in Patent Office: 764 Days
• Field of Search: 340/686, 340/457, 340/425.5, 340/438, 340/439, 123/198 D, 220/DIG. 33, 220/746, 220/86.2, 220/366, 220/367, 73/40
• US Class Current: 340/457
• CPC Class Codes: B60R 16/0232 for measuring vehicle parameters and indicating critical, abnormal or dangerous conditions
• CPC Class Codes: Y10S 220/33 Gasoline tank cap

Abstract

An automotive fuel filler pipe cap detection system has a filler pipe cap retainer on the end of the filler pipe for retaining the filler pipe cap, a passage through the cap retainer with a line outlet leading to a vacuum line connected to a manifold, and a seal outlet leading to the underside of the fuel cap when it is in place. Vacuum is generated in the vacuum line when the engine is started with the cap covering the seal outlet. A two position pressure switch connected to the vacuum line is in a first position when vacuum is sensed in the vacuum line and a second position when vacuum pressure is not sensed. A "fuel cap missing" indicator is lit to warn the operator when the switch is in the second position.

Claims

1. A filler pipe cap detection system for an automobile having an engine and a fuel tank, comprising:

a fuel filler pipe having a tank end in fluid communication with said fuel tank, and a filler end for receiving fuel from a fuel source;

a fuel filler pipe cap removably attachable to said filler end of said filler pipe;

a line having a vacuum end connected to a vacuum source, and a cap end abutable to said cap such that said cap obstructs air flow to said line when said cap is attached to said filler pipe and such that air is able to flow through said line when said cap is removed; and

means for sensing vacuum pressure in said line and for switching between a first position and a second position dependent upon pressure in said line, said means for sensing and switching in said first position when vacuum pressure is sensed in said line and in said second position when vacuum pressure is not sensed in said line, said means for sensing and switching comprising a pressure switch which sends an electrical signal to a means for lighting an indicator when in said second position.

2. A fuel cap detection system according to claim 1 wherein said vacuum source is an intake manifold of said engine.

3. A fuel cap detection system according to claim 1 wherein a cap retainer is attached to said filler end of said filler pipe for receiving and retaining said cap, said cap retainer having a passage with a line outlet to which said cap end attaches, and a seal outlet abutable to said cap such that said cap obstructs air flow to said passage when said cap is attached to said cap retainer, such that air is able to flow through said passage to said line when said cap is removed.

4. A fuel cap detection system according to claim 3 wherein said fuel cap has a seal attached to a filler pipe side of said cap, said seal covering said seal outlet of said passage of said cap retainer when said cap is attached to said cap retainer.

5. A fuel cap detection system according to claim 3 wherein said fuel cap has a threaded section which screws into a thread receiving portion of said cap retainer.

6. A fuel cap detection system according to claim 1 wherein said line has an orifice for limiting flow of unmetered air to said engine, said orifice located between said engine and an inlet leading to said pressure switch.

7. A fuel cap detection system according to claim 1 wherein said means for lighting is an onboard computer connected to said indicator on a dashboard within said automobile.

8. A filler pipe cap detection system for an automobile having an engine and a fuel tank, comprising:

a fuel filler pipe having a tank end in fluid communication with said fuel tank, and a filler end for receiving fuel from a fuel source;

a fuel filler pipe cap removably attachable to said filler end of said filler pipe;

a cap retainer fixedly attached to said filler end of said filler pipe, said retainer having means for attachment to said fuel filler pipe cap;

a passage in said cap retainer having a seal end and a line end, said seal end abutable to said cap such that said cap obstructs air flow to said passage when said cap is attached to said cap retainer, air able to flow through said passage when said cap is removed;

a line connecting said line end of said passage with a vacuum source; and

means for sensing vacuum pressure in said line and for switching between a first position and a second position dependent upon pressure in said line, said means for sensing and switching is a pressure switch in said first position when vacuum pressure is sensed in said line and in said second position when vacuum pressure is not sensed in said line, said means for sensing and switching sending an electrical signal to a means for lighting an indicator when in said second position.

9. A fuel cap detection system according to claim 8 wherein said vacuum source is an intake manifold of said engine.

10. A fuel cap detection system according to claim 8 wherein said fuel cap has a threaded section which screws into a thread receiving portion of said cap retainer.

11. A fuel cap detection system according to claim 8 wherein said line has an orifice for limiting flow of unmetered air to said engine, said orifice located between said engine and an inlet leading to said pressure switch.

12. A fuel cap detection system according to claim 8 wherein said means for lighting is an onboard computer connected to said indicator on a dashboard within said automobile.

13. A method for detecting the presence of a fuel filler pipe cap of an automobile having an engine and a fuel tank, comprising:

providing a fuel filler pipe having a tank end in fluid communication with said fuel tank, and a filler end for receiving fuel from a fuel source;

fixedly attaching a cap retainer to said filler end of said filler pipe for receiving and retaining a filler pipe cap, said filler pipe cap removably attachable to said cap retainer;

coring a passage in said cap retainer such that said passage has a line outlet and a seal outlet;

connecting a line having a vacuum end and a cap end to a vacuum source and to said line outlet of said cap retainer, respectively;

positioning said seal outlet such that said filler cap obstructs air flow to said seal outlet when said filler cap is attached to said cap retainer, air able to flow into said seal outlet, through said passage, into said line outlet, and into said line when said cap does not obstruct said seal outlet; and

sensing vacuum pressure in said line and switching between a first position and a second position dependent upon pressure in said line with a means for sensing and switching, said means for sensing and switching in said first position when vacuum pressure is sensed in said line and in said second position when vacuum pressure is not sensed in said line, said means for sensing and switching comprising a pressure switch which sends an electrical signal to a means for lighting an indicator when in said second position.

14. A method according to claim 13, further including the step of generating vacuum for said vacuum source with an intake manifold of said engine.

15. A method according to claim 13, further including the step of removably attaching said filler cap to said cap retainer with a threaded section on said filler cap which screws into a thread receiving portion of said cap retainer.

16. A method according to claim 13, further including the step of limiting flow of unmetered air to said engine by placing an orifice between said engine and an inlet leading to said pressure switch.

17. A method according to claim 13, further including the step of lighting said indicator by electrically relaying the absence of vacuum pressure in said line to an onboard computer connected to said indicator on a dashboard within said automobile.