Low fuel warning systems for a motorized vehicle

• US 7,940,165 B1
• Filed: 08/21/2007
• Issued: 05/10/2011
• Est. Priority Date: 08/21/2006
• Status: Active Grant

• Current Assignee: Hyster-Yale Group Inc.
• Original Assignee: NMHG Oregon, LLC
• Inventors: Billings, David S., Bansal, Ashwani K., Stephenson, Jeffrey G., Oxley, Lonnie R., Helton, Darrell E.
• Primary Examiner(s): Wu; Daniel
• Assistant Examiner(s): POINT, RUFUS C
• Application Number:
  US11/842,923
• Time in Patent Office: 1,358 Days
• Field of Search: 340/450, 340/450.2, 340/450.3, 340/612, 340/613, 340/603, 340/614, 340/615, 340/618, 340/438, 732/90.R
• US Class Current: 340/450.2
• CPC Class Codes: B60K 15/03006 Gas tanks B60K15/07 takes precedence
• CPC Class Codes: B60K 2015/03217 Fuel level sensors
• CPC Class Codes: F02D 19/025 Failure diagnosis or prevention; Safety measures; Testing
• CPC Class Codes: F02D 19/027 Determining the fuel pressure, temperature or volume flow, the fuel tank fill level or a valve position
• CPC Class Codes: F02D 19/029 Determining density, viscosity, concentration or composition
• CPC Class Codes: F02M 21/0212 comprising at least 3 C-Atoms, e.g. liquefied petroleum gas [LPG], propane or butane
• CPC Class Codes: F02M 21/0287 characterised by the transition from liquid to gaseous phase F02M21/06 takes precedence; Injection in liquid phase; Cooling and low temperature storage
• CPC Class Codes: F02M 37/0082 Devices inside the fuel tank other than fuel pumps or filters electrical pumps submerged in fuel tanks F02M37/10, jet pumps F02M37/025
• CPC Class Codes: Y02T 10/30 Use of alternative fuels, e.g. biofuels

Abstract

The low fuel warning system includes a fuel line configured to transport fuel between an inlet port and an outlet port and a reservoir located intermediate to the inlet port and the outlet port, wherein the reservoir is configured to collect the fuel in a liquid state. The low fuel warning system further includes a fuel sensor located adjacent the reservoir and configured to detect the liquid state of the fuel and a processor in communication with the fuel sensor. The processor is configured to monitor a low fuel condition in the fuel line according to information received from the fuel sensor.

Claims

1. A propane fuel sensor comprising:

a signal generating apparatus that generates a signal in an effective signal path to detect a presence of propane fuel in a fuel line, wherein the propane fuel sensor is mounted to the fuel line intermediate an inlet port and an outlet port of the fuel line;

a fuel trap comprising;

a first cross-section area configured to trap liquid propane fuel as the propane fuel is transmitted through the fuel line and past the signal generating apparatus, wherein the propane fuel enters the fuel trap via the inlet port, and wherein the propane fuel leaves the fuel trap via the outlet port; and

a second cross-section area configured to concentrate the liquid propane fuel transmitted past the signal generating apparatus, wherein the second cross-section area is smaller than the first cross-section area; and

a housing containing the signal generating apparatus and the effective signal path, wherein the housing is in contact with the propane fuel passing through the fuel trap and past the housing for detection by the effective signal path.

2. The propane fuel sensor according to claim 1, wherein the fuel trap is located at least partially below the inlet port to separate the liquid propane fuel from fuel vapor passing through the fuel line.

3. The propane fuel sensor according to claim 1, wherein the fuel trap is located in a secondary fuel line connected to the inlet port and the outlet port, and wherein the secondary fuel line runs substantially parallel with the fuel line.

4. The propane fuel sensor according to claim 1, wherein the signal generating apparatus is located at least partially below the fuel trap.

5. The propane fuel sensor according to claim 1, further comprising a flexible attachment attached to the housing such that the signal generating apparatus is configured to move within the fuel trap due to gravity.

6. The propane fuel sensor according to claim 5, wherein the fuel trap is located within the housing.

7. The propane fuel sensor according to claim 1, wherein the second cross-section area provides a restrictive gap that concentrates the liquid propane fuel next to the signal generating apparatus.

8. The propane fuel sensor according to claim 1, further comprising a processor, wherein the processor is configured to monitor a low fuel condition for a motorized vehicle according to information received from the propane fuel sensor, wherein the low fuel condition indicates that fuel vapor is being drawn into the fuel line, and wherein the motorized vehicle substantially operates on the fuel vapor when the low fuel condition is indicated.

9. A propane fuel system of a motorized vehicle comprising:

a first portion of a fuel line comprising a first cross-section area;

a second portion of the fuel line located intermediate a propane fuel tank and a propane engine, wherein the second portion of the fuel line comprises a second cross-section area smaller than the first cross-section area to form a restrictive gap;

a fuel sensor located adjacent the restrictive gap and configured to detect propane fuel as it passes through the restrictive gap, wherein the restrictive gap is configured to concentrate liquid propane fuel passing by the fuel sensor; and

a processor in communication with the fuel sensor, wherein the processor is configured to monitor a low fuel condition in the propane fuel system according to information received from the fuel sensor, wherein the low fuel condition indicates that fuel vapor is being drawn into the fuel line, and wherein the motorized vehicle substantially operates on the fuel vapor when the low fuel condition is indicated.

10. The propane fuel system according to claim 9, wherein the fuel sensor comprises an emitter and a receiver, wherein the emitter is configured to transmit one or more signals to the receiver, and wherein the information received from the fuel sensor corresponds with the one or more signals.

11. The propane fuel system according to claim 10, wherein the processor identifies the low fuel condition according to a number of the one or more signals received by the receiver during a predetermined time period.

12. The propane fuel system according to claim 9, wherein the fuel sensor is located in a cooler portion of the fuel line that promotes a formation of the liquid propane fuel, and wherein the cooler portion of the fuel line is located remotely from a fuel vaporizer.

13. The propane fuel system according to claim 9, further comprising a fuel sensor housing connected to the fuel line, wherein the fuel sensor comprises a lens portion that is configured to contact the liquid propane fuel until the low fuel condition develops, and wherein the restrictive gap is located between the lens portion and the fuel sensor housing.

14. The propane fuel system according to claim 13, wherein the lens portion is located adjacent the restrictive gap where a maximum flow restriction of the propane fuel occurs.

15. The propane fuel system according to claim 9, further comprising:

an inlet port of the fuel line located between the restrictive gap and the propane fuel tank; and

an outlet port of the fuel line located between the restrictive gap and the propane engine, wherein the outlet port is oriented in an approximately vertical orientation, and wherein the inlet port is oriented in an approximately horizontal orientation to facilitate venting the fuel vapor from the inlet port and draining liquid droplets through the outlet port.

16. The propane fuel sensor according to claim 9, wherein the propane fuel is transmitted through the fuel line due to a pressure created in the propane fuel tank from a conversion of the liquid propane fuel to the fuel vapor.

17. A method, comprising:

receiving signals from a propane fuel sensor located in a portion of a fuel line intermediate a propane fuel tank and a propane engine, wherein the portion of the fuel line comprises a fuel trap configured to trap liquid propane fuel passing through the fuel line, wherein the propane fuel sensor comprises a lens portion that is located adjacent the fuel trap to concentrate the liquid propane fuel passing by the propane fuel sensor until a low fuel condition develops, wherein the fuel line is located within a motorized vehicle, and wherein the propane fuel sensor is in contact with propane fuel passing through the fuel trap;

determining a number of the signals received from the propane fuel sensor;

identifying the low fuel condition when the number of the signals received from the propane fuel sensor exceeds a threshold value;

alerting a vehicle operator of the low fuel condition; and

commanding a low fuel mode of operation of the motorized vehicle, wherein the propane engine substantially operates on fuel vapor in the low fuel mode of operation.

18. The method according to claim 17, further comprising restricting an engine speed of the motorized vehicle to a maximum operational value in the low fuel mode of operation.

19. The method according to claim 17, wherein the low fuel condition indicates a presence of the fuel vapor in the fuel line.

20. The method according to claim 17, wherein the low fuel condition is identified when a predetermined uninterrupted consecutive number of the signals are received.

21. The method according to claim 17, wherein the low fuel condition is identified when a predetermined pattern of the signals is detected.

22. The method according to claim 17, wherein the lens portion forms a restrictive gap in the fuel trap that concentrates the liquid propane fuel passing by the propane fuel sensor.

23. A motorized vehicle comprising:

a liquid propane gas (LPG) fuel tank;

an LPG engine;

a fuel line configured to transport propane fuel from the LPG fuel tank to the LPG engine;

a fuel trap located in the fuel line, wherein the fuel trap is configured to maintain a pool of liquid propane fuel as the propane fuel is transported through the fuel line;

a signal generating apparatus located at least partially within the pool of liquid propane fuel and configured to detect the propane fuel in the fuel trap, wherein the signal generating apparatus comprises a lens portion that is configured to concentrate the liquid propane fuel passing by the signal generating apparatus until a low fuel condition develops; and

a processor in communication with the signal generating apparatus, wherein the processor is configured to monitor the low fuel condition in a propane fuel system according to information received from the signal generating apparatus, wherein the low fuel condition indicates that fuel vapor is being drawn into the fuel line, and wherein the LPG engine substantially operates on the fuel vapor when the low fuel condition is indicated.

24. The motorized vehicle according to claim 23, further comprising a feed tube located inside of the LPG fuel tank, wherein the fuel vapor is drawn into the fuel line when a level of the liquid fuel drops below the feed tube, and wherein the liquid fuel below the feed tube is converted into the fuel vapor for continued operation of the LPG engine.

25. The motorized vehicle according to claim 23, wherein both the liquid propane fuel and the fuel vapor are forced into the fuel line due to vapor pressure created in the LPG fuel tank.

26. The motorized vehicle according to claim 23, wherein the LPG fuel tank is removable from the motorized vehicle, and wherein the signal generating apparatus remains on the motorized vehicle after the LPG fuel tank is removed.

27. The motorized vehicle according to claim 23, wherein the LPG engine is configured to operate on the fuel vapor for at least five minutes after the low fuel condition is indicated.

28. The motorized vehicle according to claim 23, wherein the lens portion is positioned at least partially within the fuel trap to form a restrictive gap that concentrates the liquid propane fuel passing by the signal generating apparatus.