RESERVE FUEL SYSTEM

Abstract

A reserve fuel tank retention and control (RTRC) module and a method of operating a vehicle including an engine and a main fuel tank containing a fuel, the method including mounting the RTRC module onto the vehicle; fluidly connecting the RTRC module to the engine and to the main fuel tank; actuating a valve of the RTRC module for a predetermined time to purge moisture in a fuel supply hose into the engine; and upon the main fuel tank becoming empty, actuating the valve to allow fuel from the reserve fuel tank to supply the engine.

Claims

1. A reserve fuel tank retention and control (RTRC) module for a vehicle including an engine and a main fuel tank containing a fuel, the RTRC module comprising: a fuel supply hose fluidly coupled with the engine; a fuel intake hose fluidly coupled with the main fuel tank; a first fluid subcircuit disposed between the fuel intake hose and the fuel supply hose; and a second fluid subcircuit disposed between the fuel intake hose and the fuel supply hose, the second fluid subcircuit including a reserve fuel tank; the RTRC module transitionable between a first state of operation and a second state of operation, such that: in the first state of operation, the fuel is pressurized to flow from the main fuel tank to the engine only through the first fluid subcircuit and the fuel supply hose, and in the second state of operation, the fuel is pressurized to flow from the main fuel tank to the engine through the first fluid subcircuit and the fuel supply hose and additionally through the second fluid subcircuit, the reserve fuel tank, and the fuel supply hose until the reserve fuel tank is full.

2. The RTRC module of claim 1, the first fluid subcircuit comprising a first check-valve operable to control flow of the fuel therethrough.

3. The RTRC module of claim 1, the second fluid subcircuit comprising a second check-valve positioned between the fuel intake hose and the reserve fuel tank and operable to control flow of the fuel therethrough.

4. The RTRC module of claim 3, the second fluid subcircuit further comprising a third check-valve in tandem with the second check-valve, the third check-valve fluidly connected between the second check-valve and the reserve fuel tank.

5. The RTRC module of claim 1, the second fluid subcircuit comprising a valve positioned between the reserve fuel tank and the engine, the valve being operable to control flow of the fuel therethrough.

6. The RTRC module of claim 5, further comprising an indicator configured to indicate the second state of operation responsive to the valve being operated to facilitate the flow of the fuel therethrough.

7. The RTRC module of claim 5, wherein the valve comprises a solenoid valve.

8. The RTRC module of claim 1, further comprising a timer operable to maintain the second state of operation for a predetermined time to allow the reserve fuel tank to remain full after the fuel intake hose and the fuel supply hose are purged.

9. The RTRC module of claim 1, wherein the RTRC module is transitionable to a third state of operation in response to detecting that the main fuel tank is empty, wherein in the third state of operation, the engine is operable for a predetermined time during which the fuel flows from the reserve fuel tank to the fuel supply hose.

10. A method of operating a reserve fuel tank retention and control (RTRC) module, the method comprising: fluidly coupling the RTRC module to an engine and a main fuel tank containing a fuel, the RTRC module including a fuel supply hose fluidly coupled with the engine, a fuel intake hose fluidly coupled with the main fuel tank, a first fluid subcircuit disposed between the fuel intake hose and the fuel supply hose, and a second fluid subcircuit disposed between the fuel intake hose and the fuel supply hose, the second fluid subcircuit including a reserve fuel tank; operating the RTRC module in a purging mode in which the fuel is pressurized to flow from the main fuel tank to the engine through the first fluid subcircuit and the fuel supply hose and additionally through the second fluid subcircuit, the reserve fuel tank, and the fuel supply hose until the reserve fuel tank is full; and subsequently to the operating the RTRC module in a pursing mode, operating the RTRC module in a normal operation mode in which the fuel is pressurized to flow from the main fuel tank to the engine only through the first fluid subcircuit and the fuel supply hose.

11. The method of claim 10, further comprising: detecting that the main fuel tank is empty; and operating the RTRC module in a reserve mode in which the engine is operable for a predetermined time during which the fuel flows from the reserve fuel tank to the fuel supply hose.

12. The method of claim 10, wherein the first fluid subcircuit comprises a first check-valve operable to control flow of the fuel therethrough.

13. The method of claim 10, wherein the second fluid subcircuit comprises a second check-valve positioned between the fuel intake hose and the reserve fuel tank and operable to control flow of the fuel therethrough.

14. The method of claim 13, wherein the second fluid subcircuit further comprises a third check-valve in tandem with the second check-valve, the third check-valve fluidly connected between the second check-valve and the reserve fuel tank.

15. The method of claim 10, wherein the second fluid subcircuit comprises a valve positioned between the reserve fuel tank and the engine, and the valve is operable to control flow of the fuel therethrough.

16. The method of claim 15, wherein the RTRC module further comprises an indicator configured to indicate the purging mode responsive to the valve being operated to facilitate the flow of the fuel therethrough.

17. The method of claim 15, wherein the valve comprises a solenoid valve.

18. The method of claim 10, further comprising activating a timer to maintain the purging mode for a predetermined time to allow the reserve fuel tank to remain full after the fuel intake hose and the fuel supply hose are purged.

19. The method of claim 10, further comprising mounting the RTRC module onto a vehicle such that the RTRC module is mounted on the main fuel tank, and the RTRC module is located behind a seat of the vehicle and above the engine.

20. A vehicle comprising: an engine; a main fuel tank containing a fuel; a seat; and a reserve fuel tank retention and control (RTRC) module disposed behind the seat of the vehicle, the RTRC module comprising: a fuel supply hose fluidly coupled with the engine; a fuel intake hose fluidly coupled with the main fuel tank; a first fluid subcircuit disposed between the fuel intake hose and the fuel supply hose; and a second fluid subcircuit disposed between the fuel intake hose and the fuel supply hose, the second fluid subcircuit including a reserve fuel tank; the RTRC module transitionable between a first state of operation and a second state of operation, such that: in the first state of operation, the fuel is pressurized to flow from the main fuel tank to the engine only through the first fluid subcircuit and the fuel supply hose, and in the second state of operation, the fuel is pressurized to flow from the main fuel tank to the engine through the first fluid subcircuit and the fuel supply hose and additionally through the second fluid subcircuit, the reserve fuel tank, and the fuel supply hose until the reserve fuel tank is full.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The present disclosure will now be described in greater detail based on non-limiting exemplary embodiments and with reference to the drawings, on which:

[0011] FIG. 1 is a side view of a vehicle including an RTRC module;

[0012] FIG. 2 is a perspective view of an embodiment of the RTRC module of FIG. 1;

[0013] FIG. 3 is a schematic view of electrical and fluid circuits of the FTRC module of FIG. 1;

[0014] FIG. 4 is a perspective view of another embodiment of the FTRC module of FIG. 1;

[0015] FIG. 5 is a top view of the FTRC module of FIG. 4;

[0016] FIG. 6 is a flowchart depicting an embodiment of the operation of the FTRC module; and

[0017] FIGS. 7 to 9 are perspective views of embodiments of the FTRC module of FIG. 1 showing different securement arrangements.

DETAILED DESCRIPTION

[0018] Turning first to FIG. 1, an RTRC module 100 is shown mounted on a vehicle 10, e.g. a fork truck, having an engine 12, a main fuel tank 14, a safety cage 16, and a seat 18 for an operator of vehicle 10. Main fuel tank 14 is located behind seat 18 above engine 12. RTRC module 100 is mounted on top of main fuel tank 14 and includes a reserve fuel tank 110 (see FIG. 4). A fuel supply hose 20 fluidly connects RTRC module 100 and engine 12.

[0019] RTRC module 100 is removable and substantially portable, meaning that can be easily transported and mounted to a vehicle, and then removed from the vehicle. By substantially portable it is meant that the module can be lifted and moved by personnel without use of lifting equipment, although some individuals might not have the physical strength to lift and carry the module by themselves. The RTRC module includes a control circuit designed to facilitate fluid connection of main fuel tank 14 or reserve fuel tank 110 to the engine. Use of FTRC module 100 reduces downtime and increases payback on the vehicle. Additionally, while prior art circuits may be designed to purge condensation to the environment, FTRC module 100 purges directly to the engine. The timed function of valve 146 ensures purging is sufficient.

[0020] Although the FTRC module is generally described in the context of a propane powered fork truck, it should be understood that the FTRC module can be used with any vehicle that can be fueled from a reserve tank.

[0021] Turning now to FIG. 2, RTRC module 100 comprises an enclosure 102 having a base 104 and a lid 106. A control actuator 130, illustratively an electric switch, is located on a side of enclosure 102, preferably on a side of base 104. Hoses 120 and 122 are shown extending from base 104 of enclosure 102. A conduit 124 also extends from base 104 and is connected (not shown) to the battery of the vehicle. A plurality of fasteners 126 secure lid 106 to base 104.

[0022] FIG. 3 is a schematic view of embodiments of fluid and electrical circuits 140, 160, respectively, of FTRC module 100. Fluid circuit 140 comprises a first subcircuit 150 and a second subcircuit 152. First subcircuit 150 extends between junctions ABEF, from fuel intake hose 122 through a first check-valve 142 to fuel supply hose 20.

[0023] When first subcircuit 150 is pressurised, or active, the vehicle is in a normal state of operation or in a purging state of operation, in both states fuel pressure from main fuel tank 14 causing fuel to flow from junction A through first check-valve 142, junction E, and supply fuel hose 20, to engine 12. In the purging state, valve 146 is open and fuel pressure from main fuel tank 14 also causes fuel to flow from junction B through a second check-valve 144, reserve fuel tank 110, valve 146, and supply fuel hose 20, to engine 12, thereby purging the system. After the purging state valve 146 is closed and reserve fuel tank 110 is full.

[0024] Electrical circuit 160 includes a battery 162, electric switch 130, a timer 166 connected to electric switch 130, and a reserve mode indicator 168, illustratively a light. In the present embodiment, electrical circuit 160 is connected to the solenoid of valve. When the switch is closed, current flows from battery 162 through the solenoid valve, causing it to open. Closing of the switch also starts timer 166 and energizes indicator 168.

[0025] Timer 166 and indicator 168 can be integrated with actuator 130 in one device. Alternatively, timer 166 and indicator 168 may be provided separately.

[0026] In some embodiments, actuator 130 and valve 146 are integrated in one device. The single device may be a mechanically actuated valve.

[0027] FIG. 4 is a perspective view of another embodiment of FTRC module 100. In the present embodiment, two check-valves 144 are used. The inventors observed serendipitous occurrence of a dribbling event when only one check-valve 144 is used that causes fuel from reserve tank 100 to slowly bleed fuel to the engine, emptying and thus reducing the reserve fuel capacity of reserve fuel tank 100. Adding a second check-valve 144 provides a positive shut-off and prevents dribbling.

[0028] As shown in FIG. 4, fluid circuit 140 comprises a number of T-and elbow connectors coupling the check valves, valve 146, and reserve fuel tank 110. FIG. 5 is a top view of the embodiment of the FTRC module of FIG. 4. Preferably the T-and elbow connectors, and any conduits therebetween (collectively, fittings), are made of brass. Preferably the fittings comprise a common internal diameter.

[0029] In operation, when fuel from main fuel tank 14 is exhausted, engine 12 shuts down. To restart the engine in the reserve mode, the user engages actuator 130 to open valve 146, and indicator 168 indicates the reserve mode of operation is active for a period of time set by the timer. When the timer runs out, valve 146 closes and the reserve fuel stops flowing, shutting down engine 12 after the predetermined time set by the timer. Of course the timer could be provided by an integrated circuit in a chip programmed with the predetermined time or, a first predetermined time to set the purging mode duration and a second predetermined time to set the reserve mode operation. The chip, or controller, can include outputs to control the valve and various indicators and inputs to receive signals from a switch or switches configured for actuating the valve, either for the predetermined time, or the first and second predetermined times.

[0030] In some embodiments of the FTRC module, inlet and outlet ports are connected to base 104 providing junctions B and E. Fittings inside the FTRC module fluidly connect the inlet and outlet ports to the check-valves and the valve. In such embodiments external hoses connect the inlet and outlet ports to the engine and the main fuel tank.

[0031] An embodiment of a method of operating a vehicle with a FTRC module will now be described with reference to a flowchart 170 depicted in FIG. 6. The method begins, at 172, by mounting and fluidly connecting the FTRC module to the engine and main fuel tank of a vehicle.

[0032] At 174, valve 146 is actuated to purge the fluid lines and fill the reserve fuel tank. The fluid lines are purged to the engine and not the environment. Purging may be necessary because air may have entered the fluid subsystem and condensation may have been formed due to temperature differentials and changes in fuel pressure. As described above, valve 146 may be a solenoid valve actuated by an electric switch when a user actuates the switch.

[0033] A timer may be started when valve 146 is actuated. At 176, the electrical subsystem waits for time to run out, and when the time runs out the timer causes the electrical switch to close, at 178, allowing the reserve fuel tank to remain full after the lines have been purged.

[0034] Meanwhile, at 180, the engine can be operated because it receives fuel from the main fuel tank and or the reserve fuel tank prior to the closing of valve 146.

[0035] The engine can be operated until the main fuel tank empties, at 182, at which time the engine is starved of fuel and stops, potentially dead in the isle.

[0036] The operator may, at 184, actuate valve 146 to allow reserve fuel, at 186, to supply the engine. The check-valves prevent backflow to the main fuel tank. The vehicle may now be operated by a period of time set by the timer that controls valve 146.

[0037] The FTRC module can be fluidly connected to the engine at any time, including before the main fuel tank is empty or after it is refilled or replaced.

[0038] Valve 146 may be a mechanical or pneumatically operated valve using any known mechanically or pneumatically actuated valve, which are well known.

[0039] In one variation, two timers, with respective electrical switches, may be used in parallel, one timer/switch combination to control purging time after connection of the FTRC module to the main fuel tank and another to control duration of the reserve mode of operation. In another variation, a switch/timer combination may be used to control purging and a switch without timer may be used to engage the reserve mode of operation, in which case the engine may run until the reserve fuel tank empties. In a third variation, a switch without timer may be used to control purging and engage the reserve mode of operation. Without a timer, however, it is possible for the operator of the vehicle to forget to switch the valve off, thereby running the engine without reserving fuel in the reserve fuel tank. A single timer/switch combination is simpler and less expensive and therefore preferred.

[0040] FIGS. 7 to 9 are perspective views of embodiments of the FTRC module showing different securement arrangements. Fork trucks may utilize single straps 200 (FIG. 7), dual straps 210 (FIG. 8), or steel belts 220 (FIG. 9) to secure the main fuel tank 14 to the fork truck. Some form of a quick-disconnect mechanism is provided to facilitate tank removal. As shown, the quick-disconnect mechanism may involve a pivotable hook 224 and a loop 222 on the end of a strap. A tank tray 212 may be provided to secure the main fuel tank 14. These quick-disconnect mechanisms are well known.

[0041] In one embodiment, a slider plate 230 is placed between the straps and main fuel tank 14 and secured to the FTRC module at both ends to prevent that the FTRC module slides off laterally. Fasteners 232 are provided to fasten slider plate 230 to FTRC module 100. Example fasteners include screws, bolts, and rivets. Advantageously, the same slider plate 230 may be used with any strap system. In a dual strap system, fasteners (one or more) may be provided between the straps. The fasteners 232 pass through through-holes in the slider plate 230 and are then fastened to the base 104.

[0042] In a variation of the present embodiment, a self-clinching fastener, e.g. a weldnut or PEM fastener, is embedded into the base 104. Broadly defined, a self-clinching fastener (also known as clinch or captive fastener) is any device, usually threaded, that, when pressed into ductile metal, displaces the host material around the mounting hole, causing it to cold flow into a specially designed annular recess in the shank or pilot of the fastener. A serrated clinching ring, knurl, ribs or hex head prevents the fastener from rotating in the host material once it has been properly inserted. Thus, self-clinching fasteners become a permanent part of the base 104 after installation. The fasteners 232 are screwed into the self-clinching fastener to secure the slider plate 230 to the base 104. Installing and tightening the fasteners 232, thus, will clamp the retaining straps 200 in FIG. 7, or 210 in FIG. 8., to the module 100. Self-clinching fastener installation methods include pressing, broaching, or welding.

[0043] The foregoing securement arrangements advantageously permit securement of a reserve fuel tank to a fork truck without modifying the fork truck, in particular without drilling holes or welding components to the safety cage, which may be impermissible, while removably mounting the reserve fuel tank to the vehicle below the rear line of sight of the operator.