Compressed natural gas vehicle safety system and method

Abstract

A multiply-redundant system that prevents a driver from starting and/or moving a vehicle if a compressed natural gas fill system is not correctly and completely disconnected from the vehicle. One or more sensors in combination with one or more optional microswitches combine to lock-out the vehicle's ignition or otherwise prevent it from starting and/or moving. For different levels of safety, different combinations of sensors can be used with the lowest level having a single proximity sensor sensing the presence or absence of a high-pressure fill hose. The highest level of safety being achieved by having separate proximity sensors on the fuel fill hose fitting, the gas cap cover and a manual safety valve along with a redundant microswitch. An optional override that may be restricted as to the number of times it can be used can allow starting with a faulty sensor in order to allow maintenance.

Claims

1. A vehicle safety system for disabling a vehicle powered by a compressed fuel gas while fueling, the vehicle having an ignition and transmission, the vehicle safety system comprising: a proximity sensor adapted to sense presence of a gas fill hose in proximity to a tank fill adapter coupled to a pressurized gas source, said first sensor in communication with a logic circuit; the logic circuit adapted to produce a safe electrical signal indicating a safe condition when said fill hose is not in proximity to said tank fill adapter; a lockout circuit adapted to disable said vehicle when said safe electrical signal is absent; a mechanical lockout constructed to lock out the ignition or the transmission while the vehicle is fueling; a gas sensor configured to cause an alarm when said gas sensor senses a predetermined level of said fuel gas.

2. The vehicle safety system of claim 1 further comprising a break-away fitting on said gas fill hose adapted to stop gas flow if said vehicle drives away with the gas fill hose attached.

3. The safety system of claim 1, wherein the gas sensor is also coupled to the logic circuit preventing production of said safe electrical signal when the sensor senses a predetermined level of the fuel gas.

4. The vehicle safety system of claim 1 further comprising an override that overrides said logic circuit and produces said safe electrical signal when activated.

5. The vehicle safety system of claim 4 wherein said override is adapted to be used only a predetermined number of successive times

7. The vehicle safety system of claim 5 further comprising a counter circuit adapted to count successive uses of said override, and wherein said counter circuit is reset when said logic circuit produces said safe electrical signal.

8. The vehicle safety system of claim 1 wherein said proximity sensor is magnetic, optical or ultra-sonic.

9. The vehicle safety system of claim 1 wherein said compressed fuel gas is propane.

10. The vehicle safety system of claim 1 wherein said compressed fuel gas is natural gas.

11. The vehicle safety system of claim 1, wherein fueling is monitored from a remote station via a network.

12. A vehicle safety system for disabling a vehicle powered by a compressed fuel gas while fueling, the vehicle having an ignition and transmission, the vehicle safety system comprising: a proximity sensor adapted to sense presence of a gas fill hose in proximity to a tank fill adapter coupled to a pressurized gas source, said first sensor in communication with a logic circuit; the logic circuit adapted to produce a safe electrical signal indicating a safe condition when said fill hose is not in proximity to said tank fill adapter; a lockout circuit adapted to disable said vehicle when said safe electrical signal is absent; a mechanical lockout constructed to lock out the ignition or the transmission while the vehicle is fueling.

13. The vehicle safety system of claim 12 further comprising a gas sensor configured to cause an alarm when said gas sensor senses a predetermined level of said fuel gas.

14. The vehicle safety system of claim 12 wherein said compressed fuel gas is propane.

15. The vehicle safety system of claim 12 wherein said compressed fuel gas is natural gas.

Description

DESCRIPTION OF THE FIGURES

[0016] Attention is now directed to several drawings the illustrate features of the present invention:

[0017] FIG. 1A shows a block diagram of an embodiment of a high-safety lock-out system according to the present invention.

[0018] FIG. 1B shows a logic circuit that can combine sensors inputs.

[0019] FIG. 2 shows a detail drawing of a fill fixture with a proximity sensor.

[0020] FIG. 3 shows the system of FIG. 2 with the high pressure fill hose removed.

[0021] FIG. 4 shows a system similar to that of FIGS. 2-3 with an additional gas cap sensor.

[0022] FIG. 5 shows a panel-type filling system with an isolation valve and three proximity sensors.

[0023] FIG. 6 shows the system of FIG. 5 with an additional mechanical microswitch.

[0024] Several drawings and illustrations have been presented to aid in understanding the present invention. The scope of the present invention is not limited to what is shown in the figures.

DETAILED DESCRIPTION OF THE INVENTION

[0025] The present invention relates to a system and method that provides a lockout out to a vehicle's ignition, transmission or other means of moving the vehicle when a high pressure compressed natural gas fuel hose is attached to the vehicle an/or the fill cap is open. FIG. 1A shows a block diagram of an embodiment of such a system. A compressed gas fuel fitting 2 accepts a high pressure filling hose 21 that allows filling through an isolation valve 22. The isolation valve 22 can be manually opened, or it can be opened mechanically when a panel lid or “gas cap” is opened. A sensor 4, which can be an electrical proximity sensor, senses the presence of the fitting part of the high pressure filling hose 21. An optional second sensor 8 senses that the panel or gas cap is open. An optional third sensor 14 can sense the position of an isolation valve 22 (on vehicles that have such a valve). All of the sensors can be magnetic, optical or ultra-sonic proximity sensors, or any other sensors, and use any method of sensing proximity or that a particular mechanical part is or is not in a particular position. One or more optional mechanical microswitches 23 can provide a backup to one or more of the sensors.

[0026] A further logic circuit 24 or other lockout which can be a separate unit, or part of the vehicle's processor, can combine the inputs from all the sensors 4, 8, 14, and the optional microswitch 23 to produce a safe signal 25 that will allow the vehicle ignition to start the car, or otherwise allow the vehicle to move. FIG. 1B shows a schematic representation of this circuit 24. Here, each sensor's signal is amplified and conditioned and fed into an AND logic circuit 26. If any of the sensors is in an unsafe condition, the AND circuit 26 will not produce a “safe” signal. The particular circuit of FIG. 1B assumes that a proximity sensor has a logic high when there is proximity, and that the microswitch is high when the lid is closed. Any other logic levels or configurations can be used. In particular, a program in a microcontroller or other processor could also make the determination. As is well understood in the art, an OR circuit could also be effectively used instead of an AND circuit. Any circuit or program that combines sensor inputs to make a “safe” determination is within the scope of the present invention.

[0027] FIG. 1B also shows an override 27 that can be used to force a “safe” condition when one of the sensors is in an unsafe state. This circuit is optional but, when provided, allows the driver to drive to a mechanic with a failing sensor. A counter 28 or other abuse preventer prevents the override from being used more than a predetermined number times before repairing the sensor (for example three times). The counter 28 can be optionally reset whenever the sensor logic produces a safe signal. In the present example, the driver can enter a special PIN code 29 to activate the override and override the sensors. While providing this circuit lowers the overall safety threshold of the system slightly, the act of performing the override can be made difficult enough that a driver will not routinely use it to avoid having to fix a faulty sensor. Optionally, the override could be restricted to use only by a certified mechanic. In this case, the driver would not be allowed to operate it. While a simple override switch can be used, for additional safety, a PIN or barcode or any other unique identification 29 might be required. If a PIN is used, a PIN entry method can be used such as a keypad or a card swipe. If a barcode is used, a small barcode reader can be supplied.

[0028] FIG. 2 shows a male tank adapter 2 on the vehicle with a coupled (usually spring coupled) female filling locking coupler 3 and high pressure feed hose 1. The feed hose 1 typically originates at a compressor or storage tank. A proximity sensor 4 with electrical connections 5 senses the presence of the feed hose (unsafe condition). The female locking coupler 3 typically has a connect/disconnect fitting that clamps the tank adapter 2 and makes a high pressure, leak-proof connection. It should be noted that the female filling locking coupler 3 could be a quick-release, break-away fitting. This would add a final mechanical precaution to the system where the hose would manually break free in the case that somehow the rest of the system failed.

[0029] FIG. 3 shows the same setup but with the feed hose 1 and the female locking coupler 3 uncoupled and withdrawn (safe position) from the male filling adapter 2.

[0030] FIG. 4 shows a fill cavity 6 and fill access lid 7 that swings open on hinges. A second proximity sensor 8 has a second electrical feed 9. This sensor 8 can be used in embodiments of the invention either alone or in conjunction with the feed hose sensor 4. An optional microswitch 20 is also shown.

[0031] Any type of sensor can be used with the present invention. A preferred sensor is a magnetic or optical proximity sensor; however, other sensor types can be used such as ultra-sonic sensors and others.

[0032] FIG. 5 shows a different arrangement of the fueling system. This type of system is more commonly found on trucks and larger vehicles. A panel 13 opens and closes to allow access to a tank adapter 12. An isolation valve 10 can be manually operated or can operate in conjunction with a lever 16 on the panel 13. A third proximity sensor 14 with electrical feed 15 can be used to sense whether the panel is open or closed (and hence, if the lever 16 is used with the valve 10, whether the valve is open or closed). The valve 10 isolates the tank adapter 12 from the tank when the panel is closed.

[0033] FIG. 6 shows the same embodiment as FIG. 5 except that an optional microswitch 23 has been added to the panel 13. This is a simple mechanical backup that does not rely on proximity sensors. It should be noted that any of the proximity sensors shown in the various embodiments of the present invention may be replaced by microswitches or other mechanical devices, or each proximity sensor may be optionally backed up with an additional microswitch. In addition, FIG. 6 shows an optional additional microswitch 21 on the isolation valve 10.

[0034] It should be noted that an optional natural gas leak sensor can also be included with the system of the present invention to provide an addition source of safety. Such a sensor could keep the vehicle in a disabled state if an unreasonable concentration of free natural gas is sensed. Such a sensor could also sound an alarm on the vehicle or on the compressor. It is also possible that any of the above-mentioned sensors or circuits can communicate with the lockout or other logic wirelessly such as by radio or light. Finally, it should be noted that a processor with memory and a stored program can perform the logic function of the lockout, override and/or abuse preventer. This can also be any digital or analog logic circuit or simply relays. In addition, an internet or network interface can be provided to remotely report or log the status of the system. This feature can be useful for fleet operators to track safety, for example, the number of attempts to drive off under a lockout condition or the number of overrides.

[0035] The present invention provides a multiply-redundant system to enhance the safety of home or business fueling of compressed natural gas vehicles. It can also be used on vehicles using propane or any other compressed gas fuel. A system of one or more sensors determines if the fueling system is in a safe state. This can be a state with the high pressure fill hose removed, the fueling compartment access lid closed, and any isolation valve in the correct position. A lockout prevents either the vehicle from starting or otherwise makes it impossible to move the vehicle when the system is not in a safe state. In order that a driver can get a faulty sensor repaired, an override can be provided that allows the safety sensors to be overridden and the vehicle moved. This override can be equipped with an abuse preventer that only allows the override to be used for a predetermined number of times before the override itself is disabled. This prevents a driver from putting off getting a faulty sensor repaired. An audio and/or visual indicator can sound or display when the driver inserts the key into the ignition in an unsafe state, or alternatively, when the driver turns the key to start.

[0036] In the present invention, a lockout is any method, means or technique to prevent a vehicle from moving including a circuit or module that can disable the ignition or transmission or disable the vehicle in any other way. An override is a any method, means or technique to allow the vehicle to move in spite of the lockout - any way of overriding the lockout. An abuse preventer is any method, means or technique to prevent abuse of the override by limiting the number of times (especially successive times) it can be used.

[0037] Several descriptions and illustrations have been presented to aid in understanding the features of the present invention. One with skill in the art will realize that numerous changes and variations may be made without departing from the spirit of the invention. Each of these changes and variations is within the scope of the present invention.