WO2003018973A2

WO2003018973A2 - Audit vehicle and audit method for remote emissions sensing

Info

Publication number: WO2003018973A2
Application number: PCT/US2002/025140
Authority: WO
Inventors: Craig S. Rendahl; John Didomenico; Ronald J. Mcneill; Robert A. Gentala
Original assignee: Spx Corporation
Priority date: 2001-08-23
Filing date: 2002-08-09
Publication date: 2003-03-06
Also published as: WO2003018973A3; US20030040863A1; US6757607B2; AU2002356184A1

Abstract

An audit vehicle and audit method are provided for testing the performance of a remote emissions sensing system. The vehicle emits known gases. The vehicle includes a gas delivery system and senses and records telemetry information such as vehicle speed read by a sensor on a non-driven wheel, GPS information, atmospheric information, IR light information, road temperature sensing information, and gas flow rate information.

Description

Audit Vehicle and Audit Method for Remote Emissions Sensing FIELD OF THE INVENTION [0001] The present invention relates generally to systems and methods for

auditing the performance of remote (also called open path) vehicle emissions sensing

systems. More specifically, the present invention relates to an audit vehicle and audit

method that can be used to drive through a remote vehicle emissions sensing system

whole releasing a known quantity and mixture of gas to test the performance of the

sensing system.

BACKGROUND OF THE INVENTION [0002] Systems are known in the art for detecting the tail pipe emissions or

exhaust plumes of the vehicles as they drive on a vehicle path such as a roadway. For

example, it is known for a light beam to be projected across the roadway and received by

a receiver that analyzes the received light and determines the components of the vehicles emissions. In order to test the performance of such systems, it is desirable to have a

vehicle that emits known volumes, mixtures, and concentrations of gases and that can be

driven through the sensing system in order to test the detection performance of the

system.

SUMMARY OF THE INVENTION [0003] It is therefore a feature and advantage of the present invention to

provide a vehicle that emits known volumes, mixtures, and concentrations of gases and

that can be driven through the system in order to test the detection performance of the

system.

[0004] It is another feature and advantage of the present invention to provide

a method for testing or auditing vehicle emissions sensing systems. [0005] The above and other features and advantages are achieved through the

use of a novel apparatus and method as herein disclosed. In accordance with one

embodiment of the present invention, an apparatus for dispensing gas from a vehicle has

a plurality of compressed gas cylinders filled with known concentrations of gases,

referred to also as "gas bottles"; a plurality of shutoff valves, one valve associated with

each of the gas bottle for controlling gas flow out of that gas bottle; a manifold that

receives gas from each of the shutoff valves and leads to a single pressure regulator; an

output gas line leading from the pressure regulator; a mster shutoff valve that controls the

release of the audit gas; and a sample gas outlet opening at the end of the output line with flow through the output line measured.

[0006] In accordance with another embodiment of the present invention, a

system for recording telemetry data associated with a remote emissions audit vehicle,

includes: a central computer; and at least one telemetry sensing device comprising at least one of: a vehicle speed sensor mounted at a non-drive wheel; a global positioning system

sensor; ambient atmospheric condition sensors; an infrared beam detector; and an output gas flow rate sensor. Data from at least one sensing device is stored by the computer.

[0007] In accordance with another embodiment of the present invention, a

method for recording data related to the telemetry of an audit vehicle is provided. The

method includes driving the audit vehicle past a remote emissions sensor while emitting

a sample blend gas; and recording telemetry data relating to the audit vehicle. The telemetry data includes at least one of: vehicle speed read by a sensor on a non-drive

wheel, GPS information, atmospheric information, IR light information, road temperature

sensing information, and gas flow rate information. [0008] In another embodiment of the present invention, a method of

controlling gases emitted by an audit vehicle, includes controlling a plurality of operated

valves each associated with a bottle; driving the audit vehicle past a remote sensing

device; and recording data related to the audit path.

[0009] There has thus been outlined, rather broadly, the more important

features of the invention in order that the detailed description thereof that follows may

be better understood, and in order that the present contribution to the art may be better

appreciated. There are, of course, additional features of the invention that will be

described below and which will form the subject matter of the claims appended hereto.

[0010] In this respect, before explaining at least one embodiment of the

invention in detail, it is to be understood that the invention is not limited in its application

to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other

embodiments and of being practiced and carried out in various ways. Also, it is to be

understood that the pliraseology and terminology employed herein, as well as the abstract,

are for the purpose of description and should not be regarded as limiting.

[0011] As such, those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing

of other structures, methods and systems for carrying out the several purposes of the

present invention. It is important, therefore, that the claims be regarded as including such

equivalent constructions insofar as they do not depart from the spirit and scope of the

present invention. BRIEF DESCRIPTION OF THE DRAWINGS [0012] FIG. 1 is a partial respective view of a truck bed having a rack for

housing sample gas bottles.

[0013] FIG. 2 is a perspective view of a rack holding sample gas bottles and

a gas distribution system according to a preferred embodiment of the present invention.

[0014] FIG. 3 is a schematic diagram illustrating a central processing

computer and various peripheral devices that provide information to the computer.

[0015] FIG. 4 is a flow chart showing a series of steps that is performed during an audit sequence.

[0016] FIG. 5 is a flow chart showing various information that is monitored

and logged by the computer.

[0017] FIG. 6 is a flow chart that shows a method for tracking the gas

expended by an audit vehicle system.

DETAILED DESCRIPTION OF PREFERRED

EMBODIMENTS OF THE INVENTION [0018] A preferred embodiment of the present invention provides a vehicle

that emits known volumes mixtures and concentrations of gases and that can be driven through the system in order to test the detection performance of the system. A preferred

embodiment also provides a method for testing or auditing the performance of vehicle

emissions sensing systems.

[0019] A preferred embodiment of the present inventive apparatus and method

is illustrated in FIGS. 1 and 2. FIG. 1 depicts a bed in the rear portion of a vehicle 10

that may be used as the audit vehicle. A remote sensing (i.e., open-path sensing) device 2 receives a beam 4 and senses emission data when the beam 4 passes through an exhaust

gas plane. The audit vehicle 10 releases bottled gas blends, while its own exhaust is

diverted, to test the performance of the open path emissions sensor 2 that is sitting on the

side of the road. This method of auditing the open path emissions sensor 2 that sits on

the side of the road is best for emulating the entire process of a typical vehicle passing by the emissions sensor.

[0020] In a preferred embodiment, the audit vehicle 10 is a heavy duty pickup

truck that has sufficient payload performance to carry the necessary equipment used in

that embodiment. In the preferred embodiment, a rack 12 is provided to hold a number of compressed gas cylinders, also referred to as gas bottles 14, which in a preferred

embodiment, includes seven gas bottles. These gas bottles 14 can include any

appropriate number of different blends and may also include one bottle that is dedicated to a purge material (e.g. nitrogen) that can be released to purge the system of the blended gases. Each bottle contains one blend of gases. Thus, one bottle is used at a time. The

purging bottle is used between different blends, that is when switching from one blend

to another, to flush the system of any residual gases left over from the previously used

blend.

[0021] Turning to FIG. 2, in a preferred embodiment, the rack 12 holds the gas

bottles 14 as shown. Each gas bottle 14 has a primary valve 16 and outlet port as shown.

A check valve 17 is also provided at the output of each bottle 14 to prevent back filling

of the bottle. This check valve 17 is desirable, as it is possible for one of the bottles

connected to the manifold 20 to have a higher pressure, forcing a backfill until the

pressures in each bottle are the same. This backfill condition could occur if any of the

shutoff valves 18 were to remain open for more than one bottle at a time. A second check valve 19 may be used between a shutoff valve 18 and the common gas manifold 20 as

an additional measure of assurance in not contaminating the contents of one gas blend

with another. Each gas bottle 14 has a line leading to a shutoff valve 18 as shown. In a

preferred embodiment, the shutoff valve 18 is a power driven ball valve. A plunger type

solenoid valve can also be used, however a ball valve provides a good ability to handle

high pressures, such as up to 2000 psi in the gas cylinders, and when opened ball valves do not restrict the gas flow. In the preferred embodiment the ball valves are motorized

and are controlled by a computer in the cab of the vehicle as described herein. However,

in other embodiments the valves 18 can be controlled by a switch in the cab or

alternatively a switch on the outside of the valve housing that can be operated by the user to open and close the valve.

[0022] An advantage of providing multiple ball valves 18, one for each tank 14, is that the operator does not have to detach and reattach a single valve each time the

operator desires to change from one bottle to another. That is, in the preferred embodiment illustrated in FIG. 2 with multiple valves 18, the operator needs only to

disconnect each bottle 14 from its associated line when it is time to change a bottle

because it has been expended. This feature provides an ability to change between blends (that is change between bottles) very quickly while on site. Thus, in an audit

environment, this reduces the time an operator spends outside the vehicle as compared

to having to connect and disconnect a single valve each time it is desired to change between bottles. This benefit is enhanced by control of the ball valves remotely from

inside the vehicle cab.

[0023] In normal use to output a test blend, only one of the valves 18 is open

at a time, and the others are closed. A manifold 20 leading from the shutoff valves 18 and secondary check valves 19 if equipped leads to an electronic pressure sensor that

leads to a pressure regulator 24 that can be set so that the test blend (or purge gas) is

output with a known pressure, hence providing a control of the flow volume.

Downstream from the pressure regulator 24 is master release valve 25, preferably another

motorized ball valve, which is used to activate gas flow through the remaining portion

of the gas distribution system. This valve 25 can also be controlled by a central computer

from inside the vehicle cab, or can manually be operated by a momentary remote switch

located in the audit vehicle's cab. After the master release valve 25, the gas passes

through a line 26 into a output pipe 27 that leads to an output opening 29. A venturi flow

sensor 28 is present in a portion of the output pipe 27. This flow sensor 28 measures the

flow of audit gases through the gas delivery system, by sensing the pressure differential

through a venturi restriction.

[0024] FIG. 3 schematically depicts the connection of, and communication between, various components of the audit vehicle 10. The audit vehicle 10 has a

computer 30, which may be a laptop computer. The computer 30 preferably runs scientific logging software as well as audit process controlling software. The computer

30 receives vehicle speed and acceleration measurements from a wheel speed sensor 32. In preferred embodiments, the wheel sensor is mounted to a non-drive wheel of the

vehicle, such as for example, a front wheel of a pickup truck having only the rear wheels driven. This is to potentially avoid variations in speed caused by the audit vehicle's

engine, though a drive wheel sensor could be used. A non-drive wheel is specified

primarily because systems that measure vehicle speed through an apparatus that is

attached to or monitors the speed of the driveshaft and related components has proven to

be inconsistent in reporting speed and especially change in speed (acceleration). For this reason, a non-drive wheel is preferred, however data from a drive wheel, if the data is

measured from a speed sensing device at the wheel, should not be susceptible to engine

output variations, slop in the drive train, etc. that a driveshaft mounted speed measuring

system would encounter. In this case it is conceivable that data collected from even a

drive wheel should provide acceptable precision and accuracy of speed and change of

speed measurements. The sensor 32 can be an antilock brake wheel speed sensor. The

taking of data from a speed sensor on a front wheel has been found to have advantages

as compared to speed sensor that is mounted on a drive shaft because driven components

such as a drive shaft or differential are subject to speed fluctuations caused by the

vehicle's engine or loose tolerances in the various parts of the drive train. Non-drive

wheels have been found not to be subject to the same fluctuations, and hence to provide a truer and steady indication of actual vehicle speed. Speed information from the sensor

32 is fed into the central computer 30 and is monitored so that the speed at which the audit test was conducted can be verified upon later examination. Audit runs are to be

conducted within a range of speed, however the speed data will be used to audit any speed measuring devices that accompany the emissions sensor 2. The computer 30 also

calculates change in speed, i.e. acceleration, from information collected from the speed

sensor 32, and records this calculated acceleration along with the measured speed.

[0025] Also providing an input signal to the computer 30 is a GPS receiver 34. The GPS receiver 34 can provide positional data that is stored by the computer,

indicating the location at which the audit was performed. Further, GPS systems have

been found to have an ability to also provide an indication of vehicle speed. This

indication of vehicle speed can be used to compare with the wheel sensor data for sensor

32 to ensure accuracy. Further, the GPS system 34 also provides an indication of the date and time at which testing takes place, which date and time information can be stored in

the central computer 30 along with other data records to show the location date and time

and speed at which test took place.

[0026] Also attached to the computer 30 is a weather module 36, for sensing

ambient condition via a pod of sensors 37. The ambient condition sensors 37 detect

ambient conditions such as outdoor temperature, relative humidity and/or dew point, and

barometric pressure when the audit test is performed. The sensors 37 can also record

road surface temperature. This information is stored by the central computer 30 and can

be used to ensure that testing is done within a prescribed condition range, or to adjust the

results based on ambient conditions if desired.

[0027] Accordingly, the central computer 30 can store a telemetry log which

includes e.g., location, vehicle speed, ambient conditions, read temperature and the date

and time for each test.

[0028] The computer 30 also receives data from an infrared (IR) pulse sensor 38 mounted on the outside of or underneath the vehicle. The remote emissions sensing

system 2 projects an infrared beam 4. As the vehicle 10 is driven past the sensing system during an audit run, the IR sensor 38 detects the beam (and correspondingly detects that

the vehicle has just passed the emissions sensor). The IR sensor 38 sends a pulse signal to the computer 30. This pulse signal indicates the referenced time at which the vehicle

passed the emissions sensor, and can be used for several purposes. First, the time of the

pulse is stored by the computer, and thus the computer can store the other telemetry data

corresponding to that time. Further, since the GPS unit 34 gathers date & time data

from potentially the same source as the remote emissions sensing system 2 (if equipped

with a GPS that supplies date & time among other information), the time clocks of both the audit vehicle computer 30 and the remote emissions sensing system 2 will be

synchronized.

[0029] FIG. 3 also shows that the computer 30 can control thqshutoff valve 18

and master release valve 25. This permits the selection of gases from a remote location,

rather than the operator needing to manually turn valves or move components to the rear

of the vehicle. Of course, in other embodiments, the valves could be controlled remotely

in another fashion, or could be activated manually if necessary.

[0030] A power inverter 40 can be provided to take power from the audit

vehicle and invert from 12 volts DC to 110 volts AC it so that it is compatible with any

of the pieces of the equipment, such as computer 30, GPS 34, and weather monitor 36 as

necessary.

[0031] The computer 30 also receives information from a flow rate detector in the output pipe 27 and from a pressure transducer mounted in the gas manifold 22.

The detector is a venturi gas flow measurement system 28 that provides gas flow measurements to an adequate degree of precision and accuracy_^ The flow detector 28 can

be used for test accuracy and also to indicate when a gas bottle is nearly empty. The

pressure transducer 22 supplies data logged by the computer 30 regarding delivery pressure to the master release valve 25 and can be cross-verified with the pressure gage

on the mater regulator 24.

[0032] The computer 30 can also receive data from a vehicle's standard on¬

board diagnostic system (e.g., OBD), if such data is desired. The OBD system can

provide engine RPM, load on engine, and other parameters useful in quality assuring the

information gathered from speed sensor 32 and measured weather parameters gathered

by the weather module 36. [0033] FIG. 4 is a flow chart that depicts an overall audit process. At step 101,

the user decides to initiate an audit. At step 102, the user verifies that the audit vehicle

is road worthy by visually and otherwise checking the vehicle systems. This includes

verifying that the audit vehicle has enough fuel to complete the day's auditing activities.

At step 103, the user verifies that the audit vehicle has the appropriate gases and records

identifying information, such as gas cylinder serial number and certified concentrations,

in a special auditing log or in an electronic log contained within computer 30..

[0034] At step 104, the user connects exhaust diversion plumbing on the

vehicle. In a preferred embodiment of the vehicle 10, the vehicle 10 is a conventional

vehicle pickup truck, which has an exhaust diverting device mounted to it. The exhaust diverting device is .a vertical stack that has an sufficiently high so that it will not interfere

with measurement of an sample gas plume near the ground. The diverting device connects to the vehicle's exhaust system, sending the exhaust gases high above the roofline of the vehicle to assure that audit vehicle's exhaust gases do not contaminate the gases being released out the output pipe 29 from the audit gas bottles 14. A second,

dummy tail pipe, which comprises the outlet pipe 27, flow measurement system 28, and outlet 29, is also mounted to the lower rear of the vehicle and it is from where the audit

gases are released during an audit run.

[0035] At step 105 the operator verifies the location where the open path

emissions sensor 2 is sited. At step 106, the operator travels to the audit site. At step

107, the operator verifies that the open path emission sensor 2 is at the audit site. At step

108, the operator activates a power inverter, which powers equipment such as for example, the computer 30. At step 109, the operator activates the on board computer 30

and its associated telemetry sensing devices 22, 34, 36, 38 and 28. At step 110 the operator logs the computer 30 into a telemetry software application. At step 111, the

operator insures that the computer 30 is using the correct date and time which may be

provided from the GPS unit 34. At step 112, the operator conducts an intercomparison

between the audit vehicle's weather measuring equipment and the on site equipment

located within or near the open path emissions sensor 2. GPS location data 34 should

also be compered with that in the emissions sensor 2. At step 113, the operator sets

and/or checks the height of the infrared (IR) beam detector 38 that senses the IR source of the emissions sensor's 2 optical path 4, which will trigger the IR detector 38 to identify

the exact time at which the vehicle passes the open path sensing equipment. At step 114,

the operator opens the primary valves 16 of each bottle. At step 115, the operator

activates each of the shutoff valves 18 and master release valve 25 and verifies that gas

delivery is occurring at a proper flow. The bottle of purge gas is preferably left to last in the sequence of checking the delivery of gases so that the entire gas delivery system is

purges of any concentrations of audit gases. At step 117, the operator verifies that the computer 30 is gathering telemetry data. At step 118, the operator makes two to four

audit passes with the vehicle expending no gas. This is done to verify that the audit

vehicle's engine emissions are properly diverted high over the emissions sensor 2 optical

path 4. At step 119, the operator checks if the emissions sensor 2 is reading emissions even though no audit gas was passed. If so, at step 120, the operator aborts the audit

process because there will be contamination of audit gases by the audit vehicle's own

emissions. At step 121, the operator sets a traffic cone to indicate an intended gas release

start point. This provides for a consistent point of release of the audit gases by the master

release valve 25. At step 122, the operator conducts a required number of audit passes

to perform an audit. [0036] At step 123 the operator logs the computer 30 out of the audit

application. At step 124, the operator deactivates the telemetry devices 22, 34, 36, 38 and

28. At step 125, the operator deactivates the power inverter 40 to avoid running down

the battery in the audit vehicle. At step 126, the operator closes all gas bottles by closing

each primary valve 16 to avoid leakage. At step 127 the operator returns the audit vehicle

10 to its storage location. At step 128, the operator can remove and/or replace any

expended gas bottles 14. At step 129 the operator cah record observations and complete

an audit report including telemetry information from the computer 30 and emissions data

read by the emissions sensor 2 if available at the end of the auditing activities.

[0037] FIG. 5 is a flow chart depicting various information processed by the telemetry system in the computer 30. The software application is initiated at step 200,

and the date and time is initialized at step 202 from the GPS 34. Then, at step 204 the system monitors and logs the parameters including e.g., ambient temperature 212, relative humidity 214, barometric pressure 216 from weather module 36 and pod of sensors 37. Latitude and longitude 206, speed and heading 208 data are gathered from the GPS unit

34., The telemetry system also records a pulse 222 when the infrared sensor 38 senses the

sample path 4 of the emissions sensor 2. Audit gas flow rate 218 from gas flow sensor 28, and the gas manifold pressure 220 collected from the pressure transducer 22 in the

gas manifold 20 are recorded regardless of whether audit gas is released. The computer

30 calculates acceleration 211 from a change in vehicle speed 210 measured by the wheel

sensor 32.

[0038] FIG. 6 shows a feature of a preferred embodiment the invention that

tracks gas usage process when initialized in step 300. The system measures the audit gas

flow 302 via the gas flow sensor 28. The system calculates the amount of gas expended from each bottle at step 304 in the computer 30 and calculates the remaining amount of gas at step 306. At step 308, if the remaining gas is less than a predetermined value, the system warns the user of a low gas level at 310, or informs the user of the amount of gas remaining at step 312, if the remaining gas is more than the predetermined value^'. This system is effective in tracking the amount of remaining audit gas left in cylinders 14, because the amount of gas originally loaded into the cylinders is provided by the vendor of the gases. The original amount of gas must be entered into the computer 30 in order for accurate gas usage information to be available.

[0039] The many features and advantages of the invention are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the invention which fall within the true spirit and scope of the invention. Further, since numerous modifications and variations will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

Claims

What is claimed is:

1. An apparatus for dispensing gas from a vehicle, comprising:

a plurality of compressed gas cylinders;

a plurality of shutoff valves, one valve associated with each of the gas bottle for controlling gas flow out of that gas bottles;

a check valve on at least one of gas cylinder that prevents gases from flowing back into the gas cylinder;

a manifold that receives gas from each of the primary valves and leads to a pressure regulator;

an output gas line leading from the pressure regulator; and

a sample gas outlet opening at the end of the output line.

2. An apparatus according to claim 1, further comprising a master release valve

/ located on the outlet gas line downstream of the pressure regulator.

3. An apparatus according to claim 1 , wherein each of the shutoff and master

release valves is a power operated ball valve.

4. An apparatus according to claim 1 , further comprising a venturi gas flow sensor on the output gas line.

5. An apparatus according to claim 3, wherein each of the valves are controlled remotely.

6. An apparatus according to claim 3, further comprising a central computer that

controls the operation of the valves.

7. An apparatus according to claim 1, wherein the number of gas cylinders is

seven.

8. An apparatus according to claim 1, wherein one of the gas cylinders is filled with a purge material.

9. An apparatus according to claim 8, wherein the purge material is nitrogen.

10. An apparatus for dispensing gas from a vehicle, comprising:

sample gas storage means;

shutoff valve means connected to the storage means for controlling gas flow out of the storage means;

means for preventing gases from flowing into the gas storage means; a manifold that receives gas from the valve means and leads to a pressure regulator means;

a output gas line leading from the pressure regulator; and

a sample gas outlet opening at the end of the output line.

11. An apparatus according to claim 10, further comprising a master release valve means located on the outlet line downstream of the pressure regulator.

12. An apparatus according to claim 10, wherein each of the valve means is a

power operated ball valve.

13. An apparatus according to claim 10, further comprising a venturi gas flow

sensor on the outlet pipe.

14. An apparatus according to claim 11 , wherein each of the shutoff and master

release valves are controlled remotely.

15. An apparatus according to claim 11 , further comprising a central computer that

controls the operation of the valves.

16. An apparatus according to claim 10, wherein gas storage means comprises a

plurality of compressed gas cylinders also known as "gas bottles".

17. An apparatus according to claim 16, wherein one of the gas bottles is filled

with a purge material.

18. An apparatus according to claim 17, wherein the purge material is nitrogen.

19. A system for recording telemetry data associated with a remote emissions audit vehicle, the system comprising:

a central computer; and

at least one telemetry sensing device comprising at least one of:

a vehicle speed sensor mounted at a wheel of the audit vehicle;

a global positioning system sensor;

an ambient atmospheric condition sensor;

an infrared beam detector;

a pressure transducer used to measure pressure in gas delivery manifold; and

an output gas flow rate sensor;

wherein data from at least one telemetry sensing device is stored by the computer.

20. A method for recording data related to the telemetry of an audit vehicle, comprising the steps of:

driving the audit vehicle past a remote emissions sensor while emitting a sample blend gas; and

recording telemetry data relating to the audit vehicle, the telemetry data including at least one of:

vehicle speed read by a sensor on a wheel of the audit vehicle,

GPS information,

atmospheric information,

IR light information,

road temperature sensing information,

gas manifold pressure information, and

gas flow rate information.

21. A method according to claim 20, wherein change of vehicle speed is calculated from speed sensor data and is stored along with other telemetry data.

22. A method according to claim 20, wherein speed and heading data from GPS is compared and stored along with vehicle speed information from a sensor other than the GPS.

23. A method of monitoring gases emitted from at least one gas cylinder on an audit vehicle, comprising the steps of:

controlling at least one valve associated with the gas cylinder to emit gas from the gas cylinder;

measuring the rate of gas flow from the gas cylinder; and

determining the amount of gas used and/or the amount of gas remaining in the gas cylinder.

24. A method according to claim 23, further comprising the step of displaying the determined amount of gas used and/or the determined amount of gas remaining in the gas cylinder.