Patent Application
20170080374
The present invention generally relates to apparatus and methods for treatment of airstreams in an adaptive Environmental Control System (ECS) to remove particulates, such as ultrafine particles.
ECSs of various types and complexity are used in military and civil airplanes, helicopter, and spacecraft applications. In aircraft for example, airflow may be circulated to occupied compartments, cargo compartments, and electronic equipment bays. Air containing many pollutants such as particulate matter, aerosols, and hydrocarbons may range in humidity from dry (<2%) to very humid and may be delivered in a heated condition to the cabin from the ECS.
Aircraft occupants are not exposed to a single chemical and/or particulate in isolation, and the effects of co-exposures to multiple chemicals and/or particulates are poorly understood. Exposure duration for crews can be 14+ hours. Crews can routinely be assigned to work a 14 hour duty day without a break. The duty day can be extended if there is a maintenance delay or weather. Some international crews are assigned to work a longer duty day. There are flight safety and security implications for not adequately protecting pilots (who must perform cognitively-demanding safety-sensitive flight duties) and cabin crew (who must maintain cabin safety and security). Specifically, manufacturers are currently required to ensure that aircraft systems are designed to provide—in operation, under normal conditions and during any probable failure—“a sufficient amount of uncontaminated air to enable the crewmembers to perform their duties without undue discomfort or fatigue, and to provide reasonable passenger comfort.” It has been widely recognized by air accident investigators, regulators, and pilot groups that flight safety can be compromised when pilots are exposed to oil-based contaminants in the ventilation air entering from outside the aircraft through the main engine bleeds or APU bleed or other air sources including ground supplies and electric compressors. Requiring pilots to rely on their noses to identify the presence and location of bleed air contaminants prolongs the exposure for the pilots and/or cabin occupants, depending on the location of the contaminant source.
The industry accepted approach to verification of acceptability of aircraft cabin air quality has been to gather air samples through various forms of sample media to capture the range of contaminants that might be present. There are three US Environmental Protection Agency (EPA) methods that are accepted as guidance for sample collection and analysis for volatile and semi-volatile compounds and for aldehyde compounds that may create odor and create irritancy.
The sample methodology is inadequate to fully characterize all compounds with any given method, thus requiring the use of multiple methods. The analyst must also determine—based on equipment availability and laboratory capability—which methods to use.
There is limited information in the public domain related to the concentration of ultrafine particles entering the aircraft cabin during the four phases of flight (taxi, takeoff-climb, cruise, and descent). The Institute of Environment and Health (IEH) at Cranfield University has concluded that there was an association between elevated levels of ultra-fine particulate matter in the cabin air supply and when occupants detected oil odors during flight. Professor Michael Bagshaw has concluded that a level of 500,000 particle counts per cubic centimeter was associated with contamination events.
As can be seen, there may be an ongoing need to interpret real-time air particulate data and provide an indication of when the levels may increase beyond the range of acceptability to enable corrective action.
In one aspect of the present invention, an environmental control system (ECS) having particulates in air therein comprises a sensor; an air purification subsystem; and a controller in communication with the sensor and air purification subsystem; wherein the sensor: detects particulates in the air; and generates a particulate concentration signal; wherein the controller: compares the particulate concentration signal to a predicted particulate concentration threshold; wherein the predicted particulate concentration threshold is based on one of a probability of odor detection, a probability of sensory irritancy detection, and a combination thereof; and when the particulate concentration signal reaches the predicted particulate concentration threshold, commands the air purification subsystem to alter a condition in the air containing the particulates.
In another aspect of the present invention, a controller for an environmental control system (ECS) having a sensor and an air purification subsystem, wherein the controller: communicates with the sensor and air purification subsystem; receives a particulate concentration signal from the sensor; compares the particulate concentration signal to a look up table having a predicted particulate concentration threshold; and based on the comparison, commands the air purification subsystem to alter a condition of air in the ECS.
In yet another aspect of the present invention, a method of controlling particulates in air in an environment includes determining a predicted particulate concentration threshold based on one of an odor detection threshold, a sensory irritancy detection threshold, and a combination thereof; comparing the predicted particulate concentration threshold to a sensed particulate concentration in the air; and adjusting the air based on the comparison.
These and other features, aspects and advantages of the present invention will become better understood with reference to the following drawings, description and claims.
FIG. 3B1-3 is a database of particle concentrations in air samples used in a step of calculating model particle concentrations according to the method of
The following detailed description is of the best currently contemplated modes of carrying out the invention. The description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention, since the scope of the invention is best defined by the appended claims.
Various inventive features are described below that can each be used independently of one another or in combination with other features. However, any single inventive feature may not address any of the problems discussed above or may address only one of the problems discussed above. Further, one or more of the problems discussed above may not be fully addressed by any of the features described below.
As will be appreciated by one skilled in the art, aspects of the present invention may be embodied as a system, method, or computer program product. Accordingly, aspects of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a “circuit,” “module” or “system.” Furthermore, aspects of the present invention may take the form of a computer program product embodied in one or more computer readable media having computer readable program code embodied thereon.
Any combination of one or more computer readable storage media may be utilized. A computer readable storage medium is an electronic, magnetic, optical, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage medium would include the following: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium is any tangible medium that can store a program for use by or in connection with an instruction execution system, apparatus, or device.
A computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium may be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device.
Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc., or any suitable combination of the foregoing.
Computer program code for carrying out operations for aspects of the present invention may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, Smalltalk, C++ or the like and conventional procedural programming languages, such as the “C” programming language or similar programming languages. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the users computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider).
Aspects of the present invention are described below with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer readable storage medium that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the computer readable storage medium produce an article of manufacture including instructions which implement the function/act specified in the flowchart and/or block diagram block or blocks.
The computer program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.
The present invention generally provides an environmental control system (ECS) that can continuously adapt to changing particulates in contaminated air in the ECS. The contaminated air may include outside air entering the ECS through engines or an APU, or other air sources including ground supplies and electric compressors, as well as recirculating air in the ECS. A controller of the ECS may receive particulate concentration signal(s) from one or more sensors that sense particulate concentration(s) in the contaminated air.
One or more of these particulate concentration signals can then be compared against one or more predicted particulate concentration thresholds (i.e., predicted sensory response thresholds) or average predicted particulate concentration thresholds based on individual predicted particulate concentration thresholds (i.e., average sensory response thresholds based on individual predicted sensory response thresholds). The predicted sensory response threshold(s) can be based on one or more sensory thresholds for contaminants, such as odor detection thresholds and/or sensory irritancy thresholds. The odor detection threshold can be characterized by a probability of odor detection. The sensory irritancy threshold can be characterized by a probability of sensory irritancy.
If the predicted sensory response threshold is exceeded, the controller may send control signals to an air purification subsystem of the ECS to alter, for example, fan speed, air flow rate, or modulating the operating rate of an air purification system, or opening and closing valves to such an air purification subsystem in the outside air and/or recirculating air entering, for example, an environment. The thresholds of the supply air, the recirculated air, and the cabin air may be different. The method of determining thresholds can be the same for each air source or location. The threshold of the outside air divided by its sensory limit times the flow rate, plus the threshold of the recirculated air divided by its sensory limit times the flow rate, determines the total threshold of the cabin air.
The environment may be a cabin of an aircraft or other vehicle, or other space such as a building intended to be occupied by humans. Once the particulate concentration signal(s) drops below the total threshold of the cabin air, the controller may discontinue commanding the alteration of the contaminated air. Thus, the present invention thus enables continuous control of particles in the environment.
The sensor 12 can be any sensor capable of sensing the anticipated particulates in the contaminated air. One or more of the sensors can sense the concentration of particulates in the contaminant air. For example, the sensor 12 may be a smoke detector, such as a FAAST Aspirating Smoke Detector by Sensor Systems of Lincolnshire, Ill. These types of sensors and their operation is described on the Sensor Systems website in Detailed Operating Instructions, http://www.systemsensor.com/en-us/Pages/Aspiration.aspx, which is incorporated herein by reference in its entirety. The sensors must be optimized for continuous particle detection since they were originally optimized for long term averaging to minimize false alarms that are called in by the unit to a monitoring company or fire station.
An example configuration of multiple sensors in an ECS that can be employed in the present invention is shown in US patent application entitled “Aircraft Environmental Control System That Optimizes the Proportion of Outside Air From Engines, APUs, Ground Air Conditioning Units and the Recirculated Cabin Air to Maintain Occupant Comfort and Maximize Fuel Economy”, filed on Jan. 27, 2015 as Ser. No. 14/606,315 and incorporated herein by reference in its entirety.
The air purification subsystem 13 may include various coolers, fans, and filters to alter the contaminated air. An example of an air purification subsystem that can be employed in the present invention is shown in US patent application, entitled “Aircraft Environmental Control System That Optimizes the Proportion of Outside Air From Engines, APUs, Ground Air Conditioning Units and the Recirculated Cabin Air to Maintain Occupant Comfort and Maximize Fuel Economy,” filed on Jan. 27, 2015 as Ser. No. 14/606,315 and incorporated herein by reference in its entirety.
The controller 11 may then compare the particulate concentration signal(s) to a particulate concentration look up table that may have information/data of particulate concentration versus population percentile of a sample database (e.g.,
Based on the foregoing comparison, the controller 11 may then command a valve 13a to alter valve opening/closing and thereby alter a flow of outside air. Also, in addition to or in lieu of the foregoing command, the controller may command a fan 13b to alter a fan speed of recirculated air. Alternatively, the response of the controller may be to modulate an air purification device, increasing or decreasing its power to effect the desired change in air particle concentrations
Either alone or in combination with commanding the valve 13a and the fan 13b, the controller may command an outflow valve 13c to open or close. The valve 13c may enable different combinations of outside air and recirculated air to enter the cabin as cabin air 14c.
The method 20 may include, in an embodiment, a step 22, as further shown in exemplary
The method 20 may include, in an embodiment, a step 23, as further shown in exemplary
The method 20 may include, in an embodiment, a step 24, as further shown in exemplary
The method 20 may include, in an embodiment, a step 26, as further shown in exemplary
The method 20 may include, in an embodiment, a step 27 which may generally include adjusting one or more of the contaminant air sources based on the foregoing comparison(s). The adjusting may occur prior to or when the particulate concentration(s) reach a predicted particulate concentration threshold (i.e., predicted sensory response threshold).
Referring to
In the sub-step 22a, and as shown in FIG. 3B1-3, a database can be created of particulate concentrations from a plurality of air samples at four operations or phases of flight. In the exemplary embodiment of
In the sub-step 22b, and as shown in
In the exemplary embodiment shown in
In the sub-step 22c, and as shown in
Without intending to limit the scope of the present invention, it is noted that the relationship between the concentrations of contaminants in a mixture to predicted odor is believed to be similar to the relationship of concentrations of contaminants in a mixture to predicted sensory irritancy. Cometto-Muñiz, J. E., Cain, W. S., Abraham, M. H., & Gola, J. M. R. (1999). Chemosensory detectability of 1-butanol and 2-heptanone singly and in binary mixtures. Physiology & Behaviour, 67, 269-276. doi: 10.1016/S0031-9384(99)00074-8, which is incorporated herein by reference in its entirety. A strong correlation between dose additivity of a mixture on predicted odor detection levels half-way between chance and perfect detection has been reported at a probability level of 0.3 (0.00<P<0.35). Cometto-Muñiz, J. E., Cain, W. S., & Abraham, M. H. (2003). Dose-addition of individual odorants in the odor detection of binary mixtures. Behavioural Brain Research, 138, (1), 95-105. doi: 10.1016/S0166-4328(02)00234-6 which is incorporated herein by reference in its entirety. A strong correlation between dose additivity at sensory irritancy detection levels half-way between chance and perfect detection has been reported at a probability level of 0.6 (0.55<P<0.65) by Cometto-Muñiz et al. (2003).
In
Referring back to
As described in U.S. Ser. No. 14/606,617, predicted contaminant odor detection thresholds can be converted into dose addition odor ratios (i.e., probabilities of odor detection) on a population percentile basis—and either on an individual contaminant basis and/or multiple contaminant basis—as shown for example in
In
In
Again referring back to
As described in U.S. Ser. No. 14/606,617, predicted contaminant sensory irritancy detection thresholds can be converted into dose addition sensory irritancy ratios (i.e., probabilities of sensory irritancy) on a population percentile basis—and either on an individual contaminant basis and/or multiple contaminant basis—as shown for example in
In
In
Again referring back to
In an embodiment of sub-step 26a, a comparison can be made between one or more predicted sensory response thresholds (based on one or more probabilities of odor detection) and actual particulate concentration detected by one or more sensors 12.
In an embodiment of sub-step 26b, a comparison can be made between one or more predicted sensory response thresholds (based on one or more probabilities of sensory irritancy detection) and actual particulate concentration detected by one or more sensors 12.
In other embodiments, sub-step 26a and sub-step 26b need not be combined and can be alternative sub-steps.
Again referring back to
In some embodiments, the controller 11 can command adjustments to the air purification subsystem 13. As depicted in
It should be understood, of course, that the foregoing relates to exemplary embodiments of the invention and that modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims.
