WO2014085746A1

WO2014085746A1 - Wireless fuel level measurement device

Info

Publication number: WO2014085746A1
Application number: PCT/US2013/072464
Authority: WO
Inventors: Mark Daniel Leasure; Russell Lee Sanders; Matthew Jay Srnec; Carl James Breczinski; Thomas J. Davern; R. Allan Mclane
Original assignee: Thermo King Corporation; Robertshaw Controls Company
Priority date: 2012-11-30
Filing date: 2013-11-29
Publication date: 2014-06-05

Abstract

Device, system, and method for wirelessly communicating a fuel level of a fuel tank to a TRS controller. The electronics of the fuel level sensor are completely sealed and protected from the elements. The fuel level sensor can quickly connect and disconnect to a mechanical floater assembly and/or a fuel tank.

Description

WIRELESS FUEL LEVEL MEASUREMENT DEVICE

FIELD

The embodiments disclosed herein relate generally to a device for measuring a fuel level in a fuel tank of a transport refrigeration system ("TRS").

BACKGROUND

An electrical/mechanical fuel level sensor device can have a mechanical assembly connected to a potentiometer. The mechanical assembly typically has mechanical gears connected to an arm with a floater. The arm and the floater are disposed inside a fuel tank. A simple fuel level display, that is basically a dial with a needle, can be connected to the mechanical gears so that the needle moves based on the position of the floater. The metal gears can be connected to the potentiometer, such that when the metal gears move, the potentiometer's divided resistances change accordingly. The potentiometer is connected to a remote power source. Generally, the remote power source is a generator set ("genset") of a TRS and electricity is delivered through the potentiometer via an electrical wire. Accordingly, the potentiometer is powered only when the TRS is on and/or is set to provide electricity to the potentiometer. Based on the position of the arm of the mechanical assembly, the mechanical gear can move a sliding contact of the potentiometer to affect its electric potential. Accordingly, the movement of the mechanical gears due to the position of the arm displaced by the floater being floated by the fuel in the fuel tank, can change the electric potential at the potentiometer, which can be detected via the same electrical wire. The measurement of electric potential which may be an approximation of a fuel level in the fuel tank can be sent via measurement signal to a TRS controller of the TRS

The electrical/mechanical fuel level sensor device's accuracy is dependent on the mechanical design and properties of one or more of the fuel tank, mechanical gears, the arm, the floater, and the condition of the wire(s) and any wire connectors that connects the potentiometer to the vehicle's components. Accordingly, the electrical/mechanical fuel level sensor device is not accurate. In particular, the electrical/mechanical fuel level sensor device is not accurate when there is movement of the fuel in the fuel tank (e.g., movement of the transport, vibration from the engine, etc.) and/or when the fuel tank is not in a perfectly leveled position horizontally. That is, the fuel level displayed on the remote display would be inaccurate when the transport temperature controlled trailer unit is going up an incline or going down a decline, because the floater position would move up or down based on the incline or decline angle (i.e. position of the fuel in the fuel tank), and not necessarily an amount of the fuel contained in the fuel tank. There are also many other factors and conditions that prevent the electrical/mechanical fuel level sensor device from an accurate measurement of the fuel level in the fuel tank.

SUMMARY

The embodiments described herein are directed to a fuel level measurement system and a fuel level measurement device for a fuel tank of a transport refrigeration system. The

embodiments described herein include a fuel level measurement system without having a wired connection between the fuel level measurement device and a remote controller that displays the fuel level. In one embodiment, a fuel measurement system and a wireless fuel level measurement device for a TRS are provided. An embodiment of the wireless fuel level measurement device includes a memory, which stores computer instructions for calculating a fuel level, a processor in communication with the memory, which executes the computer instructions for calculating the fuel level, and a wireless network interface in communication with the processor for

communicating the fuel level to a remote controller, such as a TRS controller. The embodiment can include a battery that powers the processor, the memory, and the wireless network interface. Thus, the wireless fuel level measurement device can be powered independently from the transport's engine and/or power supply. Accordingly, the wireless fuel level measurement device does not require an electrical wire from the transport's engine to power the wireless fuel level measurement device.

An embodiment of the wireless fuel level measurement device includes a sealed casing that encases the processor, the memory, the wireless network interface, and the battery.

The sealed casing can include a housing and a potting material, wherein the processor, the memory, the wireless network interface, and the battery are disposed in the housing, and the potting material seals the housing to encase the processor, the memory, the wireless network interface, and the battery inside the sealed casing.

In an embodiment, the wireless fuel level measurement device includes a potentiometer connected to the processor for communicating raw fuel level data. The potentiometer can be contained in a compartment that is separated from a compartment of the housing containing the processor, the memory, wireless network interface, and the battery.

The potentiometer can be connected to a floater assembly, which includes a fioater configured to be floated by a fuel in a fuel tank, and an arm connected to the floater, wherein the arm is displaced when the floater is moved, and the raw fuel level data is determined by a position of the floater.

An embodiment of a fuel level measurement system includes a remote controller that displays the fuel level communicated from the wireless network interface of the wireless fuel level measurement device. The remote controller can also send data to the wireless fuel level measurement device.

An embodiment of a method for producing a sealed wireless fuel level measurement device includes providing a housing; placing logic board inside the housing, wherein the logic board includes a memory, a processor, and a wireless network interface; and completely sealing the logic board that is inside the housing by covering an opening of the housing with a layer of a potting material.

The logic board may include a battery for powering the logic board inside the housing. Alternatively, the method can include a step of placing the battery that powers the logic board inside the housing, prior to the step of completely sealing the logic board.

BRIEF DESCRIPTION OF THE DRAWINGS

Referring now to the drawings in which like reference numbers represent corresponding parts throughout.

FIG. 1 A illustrates a side view of an embodiment of a temperature controlled transport unit with a TRS.

FIG. IB illustrates a side view of an embodiment of a trailer unit with a fuel level measurement device system and a cutaway side view of a fuel tank. FIG. 2 illustrates a cutaway side view of an embodiment of a fuel level measurement device.

FIG. 3 illustrates a front perspective view of an embodiment of a fuel level sensor for a fuel tank of a transport refrigeration system.

FIG. 4 illustrates a rear view of an embodiment of a fuel level sensor for a fuel tank of a transport refrigeration system.

FIG. 5 illustrates a block diagram of an embodiment of the logic board.

DETAILED DESCRIPTION

The embodiments described herein are directed to a transport fuel level measurement device and system.

References are made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration of the embodiments in which the methods and systems described herein may be practiced. The term "reefer" generally refers to, for example, a temperature controlled trailer, container, or other type of transport unit, etc. The term "transport refrigeration system" refers to a refrigeration system for controlling the refrigeration of an in internal space of the reefer. The term "wireless" refers to a communication system that is configured to transmit data via a wireless connection over a short distance, such as, for example, between different points of a reefer that is in transport. The term "remote controller" refers to an electronic device that is configured to wirelessly communicate with another wireless device to receive data, manage, command, direct and/or regulate the behavior of the wireless device. An example of the remote controller is a TRS control unit. The term "TRS control unit" refers to an electronic device that is configured to manage, command, direct and regulate the behavior of one or more TRS refrigeration components (e.g., an evaporator, a blower, a heat exchanger, etc.), a TRS engine, a TRS main battery, a TRS alternate battery (if included in the transport refrigeration system), a TRS fuel tank, etc.

FIG. 1A illustrates a side view of a temperature controlled transport unit 100 with a TRS 50. The TRS 50 includes a transport refrigeration unit (TRU) 101, a genset (not shown), and a plurality of wireless sensors including a door sensor 113 and a fuel level sensor 114. The TRU 101 is installed on a side wall of the transport unit 100. In some embodiments, the generator set of the TRS 50 can be mounted under the transport unit 100. The TRS 50 is configured to transfer heat between an internal space 30 of the transport unit 100 and the outside environment. In some embodiments, the TRS 50 is a multizone system in which different zones or areas of the internal space 30 are controlled to meet different refrigeration requirements based on the cargo stored in the particular zone. The TRS 50 also includes a wireless communication system 10 and a fuel tank 110. The wireless communication system 10 includes a network coordinator (not shown), an antenna 20, and a plurality of wireless sensors (e.g., the door sensor 113 and the fuel level sensor 114). The wireless communication system 10 is configured to communicate information regarding the TRS 50 to a remote controller, such as a TRS controller (not shown) of the TRS 50. In some embodiments, the TRS controller can be housed in the TRU 101.

FIG. IB illustrates a side view of an embodiment of the temperature controlled transport unit 100 with a fuel level measurement system 102. The fuel level measurement system 102 includes a remote controller 104 (e.g., a TRS controller) that is in wireless communication 106 with a wireless fuel level measurement device 108. The wireless fuel level measurement device 108 is connected to a fuel tank 110 of the transport temperature controlled trailer unit 100. FIG. IB illustrates a cutaway side view of the fuel tank 110 to show the configuration of the fuel level measurement device 108 that is connected to the fuel tank 110. The fuel level measurement device 108 has a floater assembly 112 disposed inside the fuel tank 110, and the fuel level sensor 114 disposed outside the fuel tank 110.

FIG. 2 shows a cutaway side view of an embodiment of the fuel level measurement device 108 shown in Fig. IB. The fuel level measurement device 108 includes the floater assembly 112 and the fuel level sensor 114.

The floater assembly 112 includes a floater 116 configured to float on fuel housed inside the fuel tank 110 (shown in Fig. IB). The floater 116 is connected to an arm 118, which is connected to mechanical gears 120. The floater 116 and the arm 118 are configured to be disposed inside the fuel tank.

The fuel level sensor 114 includes a potentiometer 122 that connects to the mechanical gears 120. For example, the potentiometer 122 can include one or more magnets 124 that match with one or more magnets 126 of the mechanical gears 120. The potentiometer 122 can be a high impedance potentiometer for enhancing battery life (or service life) of the fuel level sensor 114. The high impedance potentiometer 122 (e.g., 30 kΩ) allows a relatively small amount of current through at this region of the circuit of the fuel level sensor 114 as compared to a low impedance potentiometer (e.g., 240 Ω). Thus, the fuel level sensor 114 including the high impedance potentiometer 122 can have a longer battery life than a sensor which uses the low impedance potentiometer.

The fuel level sensor 114 includes a casing 128. The casing 128 has a housing 130 and a layer of potting material 132. The housing 130 can be made from, for example, an epoxy encapsulant which cures at room temperature to a tough, semi-rigid polymer, which has very good resistance to water, acids and bases and organic solvents. The housing 130 has a first compartment 134 for containing the potentiometer 122, and a second compartment 136 for containing a logic board 138.

The first compartment 134 has a shaped wall portion 140 configured to mate with the floater assembly 112. For example, the first compartment 134 can include interference fitting structure (e.g., crush ribs) configured to fit tightly with the floater assembly 112. The shaped wall portion 140 is between the first compartment 134 and the second compartment 136. The shaped wall portion 140 may have one or more grooves 142 for wire(s) 144 to travel across between the first compartment 134 and the second compartment 136. The one or more grooves 142 can provide positioning of the wire(s) 144 so as to protect the wire(s) 144 from the environment (e.g., rain, snow, mud, dirt, rocks, ultraviolet rays, etc.) when the fuel level sensor 114 is installed to the fuel tank 110. For example, the grooves 142 shade the wire(s) 144 from the sun and other environmental forces that can cause damage to the wire(s) 144.

In an embodiment, the wire(s) 144 are integrally connected to the potentiometer 122 and the logic board 138, without any wire "connectors" (which generally have plastic clips and/or thin metal connectors) that can rust or wear out during normal use over time.

The housing's 130 second compartment 136 is configured to receive and contain the logic board 138. The second compartment 136 is separated from the first compartment 134, such that the second compartment 136 can contain the logic board 138 and be sealed completely and separately from the first compartment 134. The sealing of the second compartment 136 can be performed by providing the layer of potting material 132 over the logic board 138. The result provides a completely sealed logic board 138 contained in a sealed compartment 136 of the casing 128 that protects the logic board 138 from the elements. FIG. 5 illustrates a block diagram of an embodiment of the logic board 138 for the fuel level sensor 114. The logic board 138 can include (or be connected to) one more or more of a processor 200, a memory 201, a network interface 202, and a battery 203. In another

embodiment, the second compartment 136 contains one more or more of the processor 200, the memory 201 , the network interface 202, and the battery 203.

A simple fuel level display 146, that is basically a dial with a needle, can be provided at the potentiometer 122 so that the needle moves based on the position of the floater 116.

The floater 116 is floated by a fuel contained in the fuel tank. The floater 116 is connected to the arm 118 of the floater assembly 112, and the displacement of the floater 116 due to the level of the fuel rotates the arm 118 about a pivot 148 at a gear mechanism 120 of the floater assembly 112. The gear mechanism 120 is connected to the potentiometer 122 of the fuel level sensor 114, by for example, a magnetic connection so that the fuel level sensor 114 can be quickly and easily be connected and disconnected from the floater assembly 112.

FIG. 3 shows an embodiment of a front side of an embodiment of a fuel level sensor 114 of a fuel level measurement device 108. The front side of the fuel level sensor 114 would face away from a fuel tank when the fuel level sensor 114 is connected to the fuel tank. The fuel level sensor 114 has a substantially cylindrical shape in general. The substantially circular profile of the substantially cylindrical shape can reduce the fuel level sensor 114 from being damaged by the environment (e.g., road debris, etc.). The analog display 146 having a needle dial 150 is disposed at (or substantially near) the center of the fuel level sensor 114. A beveled view angle portion 152 is angled from a first surface portion 154 of the housing 130 of the fuel level sensor 114 towards the analog display 146. The beveled view angle portion 152 can enhance the visibility of the analog display 146. In some embodiments, a light-emitting diode (LED) 156 is provided to be visible on the surface portion 154. The LED 156 can be connected to the processor on the logic board 138 for displaying information regarding an operation and/or condition of the fuel level sensor 114. The LED 156 can be a single color LED. The LED 156 can be a multi-color LED for displaying different information via being lit up with each of the multiple colors. The housing 130 can include a recess for the LED 156 for enhancing viewability of the LED 156 when lit.

FIG. 4 shows and embodiment of a backside (view from the rear) of an embodiment of a fuel level sensor 114. The backside would face towards the fuel tank when the fuel level sensor 114 is connected to the fuel tank. The embodiment of the fuel level sensor 114 shows a first compartment 134 and a second compartment 136 separated by a wall portion 140, wherein the first compartment 134 is disposed near the center of a substantially cylindrically shaped housing 130, with the second compartment 136 forming a ring-shaped compartment which surrounds the first compartment 134. Accordingly, the logic board contained in the second chamber 136 can be substantially ring-shaped to match the shape of the second compartment 136.

The wall portion 140 is configured to receive a gear mechanism of a floater assembly. For example, the wall portion 140 can include an interference fitting structure 141 (e.g., crush ribs) configured to fit tightly with most conventional types of floater assembly. The interference fitting structure 141 fits the with the floater assembly, even without requiring screws to secure the floater assembly to the fuel level measurement device 108.

The first compartment 134 contains a potentiometer 122, which has wire(s) 144 extending from it. The wire(s) 144 navigate through the wall portion 140 via matching groove(s) (or channel(s)) towards a logic board contained in the second compartment 136. The second compartment 136 is completely sealed with a layer of potting material 132. In an embodiment, a fuel level sensor 114 can be added to an existing resistive fuel gauge and mechanical fuel float assembly, such that the combination provides the resistive fuel gauge to be embedded into a sealed casing with the fuel level measurement device digital component in order to provide a rugged fuel measurement device.

The embodiments of the fuel level measurement device 108 described herein can provide one or more of the following features: Communication of fuel level in a fuel tank to a remote controller is performed wirelessly (wires can degrade over time); also no external wire

connectors are needed (like wires, external connectors that connect various electrical components can wear out, be damages, rust, oxidize, etc.); and electronics of the fuel level sensor are completely sealed and protected from the elements.

Advantages of the above embodiments include, but are not limited to, an improvement in reliability of fuel level sensing technology for reefers due to elimination of exposed wires that are subject to damage during transport of the reefer; improvement in the serviceability of the fuel level sensing technology, because wired fuel sensor systems are time consuming to troubleshoot and can be costly to repair, while embodiments of the wireless fuel level measurement device can provide fast and easy installation and/or replacement of the fuel level measurement device to the fuel tank of the transport; and viewability of an analog display. For wired fuel sensor systems, wherein wires provide power to the electronic fuel level measurement devices and/or the wires are conduits of data from the fuel level measurement device to a TRS controller, the wires have been found to be subject to normal wear and tear which disables the fuel sensor system. When damaged, these systems and the wires can be time consuming to repair when there is a case of failure. A wireless fuel level measurement device and system has no exposed wires that can be damaged by normal wear and tear. Further, the wireless fuel level measurement device can be easily and quickly replaced, if there is a case of failure.

Aspects:

It is noted that any of aspects 1-14 and/or features therein can be combined with any of the aspects 15-16 and/or features therein.

1. A wireless fuel level measurement device for a fuel tank of a transport refrigeration system, comprising:

a memory, which stores computer instructions for calculating a fuel level;

a processor in communication with the memory, which executes the computer instructions for calculating the fuel level;

a wireless network interface in communication with the processor for communicating the fuel level to a remote controller; and

a battery that powers the processor, the memory, and the wireless network interface.

2. The wireless fuel level measurement device according to aspect 1, further comprising: a sealed casing that encases the processor, the memory, the wireless network interface, and the battery.

3. The wireless fuel level measurement device according to any of the aspects 1-2, wherein the sealed casing includes: a housing, and a potting material, wherein the processor, the memory, the wireless network interface, and the battery are disposed in the housing, and the potting material seals the housing to encase the processor, the memory, the wireless network interface, and the battery inside the sealed casing.

4. The wireless fuel level measurement device according to any of the aspects 1-3, wherein the fuel level measurement device has a cylindrical shape.

5. The wireless fuel level measurement device according to any of the aspects 1-4, further comprising an analog display having a needle dial disposed at a center of the wireless fuel level measurement device; and

a beveled view angle portion angled from a surface portion of the housing towards the analog display.

6. The wireless fuel level measurement device according to any of the aspects 1-5, further comprising a light-emitting diode provided on the surface portion.

7. The wireless fuel level measurement device according to aspect 6, wherein the light- emitting diode is connected to the processor, and the light-emitting diode is configured to display information regarding one or more of an operation and a condition of the fuel level sensor.

8. The wireless fuel level measurement device according to any of the aspects 6-7, wherein the light-emitting diode is a single color light-emitting diode. 9. The wireless fuel level measurement device according to any of the aspects 6-7, wherein the light-emitting diode is a multi-color light-emitting diode and configured to display different information via being lit up with each of the multiple colors. 10. The wireless fuel level measurement device according to any of the aspects 1-9, wherein the housing includes a first compartment and a second compartment separated by a wall portion, wherein the first compartment is disposed near a center of a cylindrically shaped housing, and the second compartment forms a ring-shaped compartment which surrounds the first

compartment, the processor, the memory, the wireless network interface, and the battery being contained in the second chamber, the wall portion being configured to receive a gear mechanism of a floater assembly.

11. The wireless fuel level measurement device according to aspect 10, wherein the wall portion includes an interference fitting structure configured to fit tightly with the floater assembly without requiring screws to secure the floater assembly.

12. The wireless fuel level measurement device according to any of the aspects 1-11, further comprising a potentiometer connected to the processor for communicating raw fuel level data. 13. A fuel level measurement system for a transport refrigeration system, comprising:

the wireless fuel level measurement device according to aspect 12; and

a floater assembly connected to the potentiometer, the floater assembly including:

the floater configured to be floated by a fuel in a fuel tank; and an arm connected to the floater, wherein the arm is displaced when the floater is moved, and the raw fuel level data is determined by a position of the floater.

14. The fuel level measurement system according to aspect 13, further comprising:

the remote controller that is configured to display the fuel level communicated by the wireless fuel level measurement device via the wireless network interface.

15. A method for producing a sealed wireless fuel level measurement device for a transport refrigeration system, comprising:

providing a housing;

placing a logic board inside the housing, wherein the logic board includes a memory, a processor, and a wireless network interface; and

completely sealing the logic board that is inside the housing by covering an opening of the housing with a layer of a potting material.

16. The method according to aspect 15, further comprising:

placing a battery inside the housing for powering the logic board inside the housing.

With regard to the foregoing description, it is to be understood that changes may be made in detail, especially in matters of the construction materials employed and the shape, size and arrangement of the parts without departing from the scope of the present invention. It is intended that the specification and depicted embodiment to be considered exemplary only, with a true scope and spirit of the invention being indicated by the broad meaning of the claims.

Claims

a memory, which stores computer instructions for calculating a fuel level;

2. The wireless fuel level measurement device according to claim 1, further comprising: a sealed casing that encases the processor, the memory, the wireless network interface, and the battery.

3. The wireless fuel level measurement device according to claim 1, wherein the sealed casing includes:

a housing, and a potting material, wherein the processor, the memory, the wireless network interface, and the battery are disposed in the housing, and the potting material seals the housing to encase the processor, the memory, the wireless network interface, and the battery inside the sealed casing.

4. The wireless fuel level measurement device according to claim 1, wherein the fuel level measurement device has a cylindrical shape.

5. The wireless fuel level measurement device according to claim 1, further comprising an analog display having a needle dial disposed at a center of the wireless fuel level measurement device; and

6. The wireless fuel level measurement device according to any of the claim 1, further comprising a light-emitting diode provided on the surface portion.

7. The wireless fuel level measurement device according to claim 6, wherein the light- emitting diode is connected to the processor, and the light-emitting diode is configured to display information regarding one or more of an operation and a condition of the fuel level sensor.

8. The wireless fuel level measurement device according to claim 6, wherein the light- emitting diode is a single color light-emitting diode.

9. The wireless fuel level measurement device according to any of the claim 6, wherein the light-emitting diode is a multi-color light-emitting diode and configured to display different information via being lit up with each of the multiple colors.

10. The wireless fuel level measurement device according to claim 1, wherein the housing includes a first compartment and a second compartment separated by a wall portion, wherein the first compartment is disposed near a center of a cylindrically shaped housing, and the second compartment forms a ring-shaped compartment which surrounds the first compartment, the processor, the memory, the wireless network interface, and the battery being contained in the second chamber, the wall portion being configured to receive a gear mechanism of a floater assembly.

11. The wireless fuel level measurement device according to claim 10, wherein the wall portion includes an interference fitting structure configured to fit tightly with the floater assembly without requiring screws to secure the floater assembly.

12. The wireless fuel level measurement device according to claim 1 , further comprising ; potentiometer connected to the processor for communicating raw fuel level data.

13. A fuel level measurement system for a transport refrigeration system, comprising: the wireless fuel level measurement device according to claim 12; and

a floater assembly connected to the potentiometer, the floater assembly including: the floater configured to be floated by a fuel in a fuel tank; and an arm connected to the floater, wherein the arm is displaced when the floater moved, and the raw fuel level data is determined by a position of the floater.

14. The fuel level measurement system according to claim 13, further comprising:

providing a housing;

16. The method according to claim 15, further comprising: