Method and apparatus for monitoring for a restriction in a stage II fuel vapor recovery system
View Patent ↗Systems and methods for detecting a failure in a Stage II fuel vapor recovery system are disclosed. An exemplary failure is a restriction in the vapor recovery system. In one detection system dispensing points may be flagged if it is determined that there has been a series of detected A/L ratios at the respective dispensing point below a first threshold. Further, an estimated ORVR penetration percentage may be determined for each dispensing point. In a second detection system an average A/L ratio for each dispensing point may be determined. The average A/L ratio may be an approximation of the average A/L ratio for non-ORVR transactions.
1. For a fuel dispensing system for dispensing fuel from a plurality of dispensing nozzles into ORVR and non-ORVR equipped vehicles, the fuel dispensing system including a vapor recovery system, a method for monitoring for a restriction in the vapor recovery system comprising:
determining over a period of time, for each dispensing nozzle, an ORVR penetration ratio of A/L ratios below a first threshold versus A/L ratios above the first threshold;
flagging one of the dispensing nozzles if it is determined that there has been a series of detected A/L ratios at the one dispensing nozzle below the first threshold;
upon completion of the period of time, determining an average of the ORVR penetration ratios of the non-flagged dispensing nozzles;
determining an acceptable ORVR penetration ratio as a function of the determined average ORVR penetration ratio;
comparing the ORVR penetration ratio of each of the flagged dispensing nozzles to the acceptable ORVR penetration ratio; and
providing an indication for a given flagged dispensing nozzle if the penetration ratio for the flagged dispensing nozzle is greater than the acceptable ORVR penetration ratio.
2. The method of claim 1 wherein the period of time is one day.
3. The method of claim 1 wherein the period of time is one week.
4. The method of claim 1 wherein the indication is an alarm.
5. The method of claim 1 wherein the function of the average penetration ratio is equal to [(1−average penetration ratio)/x+average penetration ratio], wherein x=a number greater than 1.
6. The method of claim 5 wherein x=2.
7. The method of claim 1 wherein the method is performed by a controller.
8. For a fuel dispensing system for dispensing fuel from a plurality of dispensing nozzles into ORVR and non-ORVR equipped vehicles, the fuel dispensing system including a vapor recovery system, a system for monitoring for a restriction in the vapor recovery system comprising:
a controller, wherein the controller;
determines over a period of time, for each dispensing nozzle, an ORVR penetration ratio of A/L ratios below a first threshold versus A/L ratios above the first threshold;
flags one of the dispensing nozzles if it is determined that there has been a series of detected A/L ratios at the one dispensing nozzle below the first threshold;
upon completion of the period of time, determines an average of the ORVR penetration ratios of the non-flagged dispensing nozzles;
determines an acceptable ORVR penetration ratio as a function of the determined average ORVR penetration ratio;
compares the ORVR penetration ratio of the flagged dispensing nozzles to the acceptable ORVR penetration ratio; and
provides an indication for a given flagged dispensing nozzle if the penetration ratio for the flagged dispensing nozzle is less than the acceptable penetration ratio.
9. The system of claim 8 wherein the period of time is one day.
10. The system of claim 8 wherein the period of time is one week.
11. The system of claim 8 wherein the indication is an alarm.
12. The system of claim 8 wherein the function of the average penetration ratio is equal to (1−average penetration ratio)/x+average penetration ratio, where x equals a number greater than 1.
13. The system of claim 12 wherein x=2.