Abstract:
A dust testing facility for static dust testing of a motor vehicle, wherein actual road dust is utilized, which dust is fully recirculated and reused, and wherein the dust testing of the motor vehicle suitably approximates a dynamic road dust test of the motor vehicle. The dust testing facility includes a dust testing chamber which receive thereinside a motor vehicle to be tested and is integrated with four major component systems: an air supply system, a dust supply system, a dust spray system interfaced with the dust supply system, and a dust recapture system interfaced with the air supply and dust supply systems. The dust testing chamber preferably includes, for purposes of dust testing of a motor vehicle, a leak detection system selectively interfaced with a motor vehicle being dust tested.

Description:
TECHNICAL FIELD  
       [0001]     The present invention relates to testing facilities used to test how a motor vehicle is affected by various environmental conditions, and more particularly to a testing facility for testing how dust affects a motor vehicle.  
       BACKGROUND OF THE INVENTION  
       [0002]     Original equipment manufacturers of motor vehicles perform various tests on prototype and production vehicles in order to ascertain their performance characteristics. Some tests involve subjecting the motor vehicle to certain environmental conditions. One of these environmental conditions is dust.  
         [0003]     It has been routine practice for dust testing of a motor vehicle to be performed by a dynamic road test in which the subject motor vehicle is driven in the open air over a predetermined road course whereat dust is present, as for example at a dirt road course (public or private) in the desert. Various aspects of the motor vehicle are impacted by dust, as for example the quality of the door sealing.  
         [0004]     In the 1970&#39;s Fisher Body, a division of General Motors Corporation, Detroit, Mich., experimented with the possible use of a dust testing chamber for motor vehicle dust testing at the General Motors Technical Center in Warren, Mich. However, the tests were inconclusive and the dust could not be recirculated. Accordingly, the dynamic road dust test was considered indispensable for the analysis of motor vehicle sealing and the dust chamber experimentation was abandoned.  
         [0005]     Applicants have heard by second-hand information that the U.S. military may have a dust testing booth in Florida, but if it exists, the workings thereof are unknown to Applicants. Applicants are also aware that Boeing Corporation of Seattle, Wash., uses a type of dust booth that involves placing oil on an aircraft wing; the dust, in conjunction with the oil, serves to seal any cracks that my be present on the wing surface.  
         [0006]     In the interim since the Fisher Body experimentation, improved air filtration systems have become available. Additionally, dry powder spray systems for paint application have been developed. These developments, combined with the time and money consumed by dynamic road tests, have given new impetus to the need to develop a successful dust testing facility for motor vehicle evaluations.  
       SUMMARY OF THE INVENTION  
       [0007]     The present invention is a dust testing facility for static dust testing of a motor vehicle, wherein actual road dust is utilized, which dust is fully recirculated and reused, and wherein the dust testing of the motor vehicle suitably approximates an outdoor dynamic road dust test of the motor vehicle.  
         [0008]     The dust testing facility according to the present invention is an environmentally closed system, wherein a dust testing chamber forms an interior chamber space which receives a motor vehicle to be tested, and wherein the dust testing chamber is integrated with four major component systems: 1) an air supply system, 2) a dust supply system, 3) a dust spray system interfaced with the dust supply system, and 4) a dust recapture system interfaced with the air supply and dust supply systems. The dust testing chamber preferably includes, for purposes of dust testing of a motor vehicle, a leak detection system selectively interfaced with a motor vehicle being dust tested.  
         [0009]     In the preferred embodiment of the dust testing facility, the dust testing chamber provides a selectively enclosable space defined by sidewalls, a ceiling, a flooring group, and at least one door, which when closed provides enclosure of the space. The air supply system includes a fan unit, temperature and humidity regulation components preferably in the form of a heating and air conditioning unit and a steam injection unit, and selectively ventable air supply ducts connected therewith to a plurality of air vents (preferably four mutually spaced air vents) located at the ceiling of the dust testing chamber. The dust supply system includes a source of compressed air, an air dryer, road dust, and a supply dust fluidizer for fluidizing the dust. The dust spray system includes a pump for providing a pressurized mixture of compressed air and the dust, dust supply conduits connected to the pump and a plurality of dust spray nozzles (preferably four mutually spaced dust spray nozzles, one dust spray nozzle for each air vent) located at the ceiling of the dust testing chamber. The dust recapture system includes the flooring group being composed of a floor grating elevated with respect to a plenum which is interconnected with return ducts to a return dust collector, including a filter unit interfaced with the air supply system, and a return dust fluidizer, which is, in turn, connected by a dust return conduit to the supply dust fluidizer.  
         [0010]     In operation of the dust testing facility, a motor vehicle is parked inside the dust testing chamber and is connected to a leak detection system through a portal in a sidewall of the dust testing chamber. Preferably for example, the leak detector holds the air pressure inside the motor vehicle at about 0.5 inch of water negative pressure (vacuum) with respect to atmospheric, and the selected pressure inside the dust testing chamber is held at about 0.1 inch of water negative pressure (vacuum) with respect to atmospheric. The air supply, dust supply, dust spray and dust return systems are selectively activated and the fluidized dust is allowed to emanate from the dust supply nozzles and commingle with the air flow (as for example at 6,000 cubic feet per minute) from the air vents to provide a copious amount of atomized dust (as for example a selectively processed Arizona road dust) around a motor vehicle parked in the dust chamber. After a predetermined time (as for example 8 minutes, during which a dust cloud has enveloped the vehicle, which cloud may be aided and directed by a plurality of fans within the dust chamber), the dust spray is stopped, but the airflow continues so as to purge the chamber of dust, and all the while recycling the dust for the next motor vehicle evaluation. The motor vehicle is then disconnected from the leak detection system, and removed for dust evaluation.  
         [0011]     As can be understood from the foregoing, the dust testing facility according to the present invention has the advantage of providing motor vehicle dust testing to be conducted year round and independent of external weather conditions by virtue of ability of the dust testing facility being able to self-regulate temperature and humidity (as for example 75 degrees Fahrenheit and 50% relative humidity).  
         [0012]     Accordingly, it is an object of the present invention to provide a dust testing facility for static dust testing of motor vehicles.  
         [0013]     This and additional objects, features and advantages of the present invention will become clearer from the following specification of a preferred embodiment. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0014]      FIG. 1  is a perspective view of a dust testing chamber of a dust testing facility according to the present invention.  
         [0015]      FIG. 2  is a schematic front view of the dust testing facility, wherein the dust testing chamber thereof is seen sectionally.  
         [0016]      FIG. 3  is a schematic side view of the dust testing chamber according to the present invention.  
         [0017]      FIG. 4A  is a schematic view of a portion of the dust return system of the dust testing facility according to the present invention.  
         [0018]      FIG. 4B  is a schematic view, seen along line  4 B- 4 B of  FIG. 4A .  
         [0019]      FIG. 5  is a schematic top plan view of a portion of the dust testing facility according to the present invention.  
         [0020]      FIG. 6  is a schematic flow chart of the dust testing facility according to the present invention.  
         [0021]      FIG. 7  is a microcontroller schematic diagram for the dust testing facility according to the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0022]     Referring now to the Drawings,  FIGS. 1 through 7  depict various aspects of a dust testing facility  10  for testing dust affects upon a motor vehicle according to the present invention.  
         [0023]     As can be seen at  FIGS. 1 through 3 , the dust testing facility  10  includes a dust testing chamber  12  having sidewalls  14  and a ceiling  16 , all composed preferably of galvanized aluminum, and a flooring group  18 , all of which being in sealing relation with respect to each other, and further including a motor vehicle access door  20 , a hinged personnel access door  20   a  and windows  20   b  (a pair of windows in each opposing sidewall). The vehicle access door  20  is preferably a roll-up type door, as for example manufactured by Albany Door Systems of Lawrenceville, Ga. For purposes of motor vehicle dust testing, it is preferred for the dimensions of the dust chamber to be about 24 feet long, 12 feet wide and 8 feet high. The flooring group  18  includes a floor grating  28  which is elevated about 1 foot above ground (for dust return purposes to be detailed hereinbelow), so that a ramp  22  is provided for moving a motor vehicle  24  to be dust tested into and out of the dust testing chamber  12 . Enclosed lighting  25 , preferably of the fluorescent type, is provided in beveled relation to the ceiling-sidewall interface along the length of the dust testing chamber  12 .  
         [0024]     The dust testing chamber  12  provides an interior chamber space  121  when the doors  20  and  20   a  are closed, wherein as can be seen at  FIG. 2 , the motor vehicle  24  to be tested fits entirely therewithin and the wheels thereof rest upon the floor grating  28 . In this regard, dust within the dust testing chamber  12  is kept therewithin during operation by maintaining an air pressure within the dust testing chamber below atmospheric pressure, as will be discussed hereinbelow.  
         [0025]     A leak detection system  90  is connected with the motor vehicle  24 , as for example at the driver&#39;s side window, so as to openly communicate with the interior vehicle space  241  of the motor vehicle, the nature of which will be discussed hereinbelow.  
         [0026]     The flooring group  18  includes the open metal floor grating  28  supported above a plenum  30  and return ducts  32  which fluidically communicate the plenum along its length. The plenum  30  is in open communication with the grating  28 , and has acutely angled plenum walls  30   w  which extend the length of the dust testing chamber  12 . The return ducts  32  run the length of the dust testing chamber  12  at the lowest point of the plenum walls  30   w , and, as such, are positioned to optimally extract dust accumulation in the plenum  30  from the, as will be understood from the operational description hereinbelow.  
         [0027]     As can be understood by additional reference to  FIG. 6 , connected to the dust testing chamber  12 , are an air supply system  34 , a dust supply system  36 , a dust spray system  38  interfaced with the dust supply system, and a dust recapture system  40  interfaced with the air flow and dust supply systems.  
         [0028]     Turning particular attention firstly to the air supply system  34 , which is shown schematically at  FIG. 5 , a fan unit  42 , as for example utilizing a 182 class fan of Twin City Co., Minneapolis, Minn., provides a source of flowing air A, having a selected flow rate, as for a preferred example of about 6,000 cubic feet per minute. Upstream of the fan unit  42 , a selected majority portion of the flowing air A is recyclably sourced from circulated air that has passed through the dust testing chamber  12 , the dust recapture system  40 , including an air filtration unit  74  of the dust recapture system, and the rest of the air is sourced from external fresh air, as needed. Downstream of the fan unit  42 , the flowing air A is conducted along air supply ducts  44  such that the flowing air passes through a heating and air conditioning unit  46  featuring an air conditioner  46   a  for cooling and dehumidifying the flowing air and a heater  46   b  for heating (or reheating after the air conditioner) the flowing air, and a downstream steam injection unit  48  for providing selective increase of humidity to the flowing air, all of which providing processed flowing air PA. In this regard it is preferred for the heating and air conditioning and steam injection units  46 ,  48  to provide processed flowing air PA having an ambient temperature of 75 degrees Fahrenheit and 50% relative humidity. The air supply ducts  44  then direct this processed flowing air PA to four mutually spaced air vents  50   a ,  50   b ,  50   c ,  50   c  located at the ceiling of the dust testing chamber  12  and fludicially communicating with the interior thereof. As will be further discussed hereinbelow, selective venting of the air supply ducts  44  and speed of the fan unit  42  are adjusted during operation of the air supply system  34  to provide a negative air pressure in the interior chamber space  121 .  
         [0029]     The dust supply system  36  includes a source  52  of compressed air CA having a pressure, for example of about 130 psi, which, via a high pressure air supply conduit  54  supplies the compressed air to an air dryer  56 , as for example Model 180HPS10AFJ, manufactured by Zeks Compressed Air Solutions of West Chester, Pa. The compressed air CA is dried, as for example to a dew point of minus 124.4 degrees Fahrenheit. A supply dust fluidizer  58  is composed of a supply dust holding tank (or bed)  60 , as for example Model 702PROX manufactured by Nordson Corporation of Westlake, Ohio. Located within the supply dust holding tank  60  is a suitable quantity of dust D, preferably road dust, and most preferably a processed road dust consisting of road dust collected from desert areas Arizona, having a size range of between 0 and 180 microns, the components thereof including free silica, as for example supplied by Powder Technologies, Inc. of Burnsville, Minn., coarse dust part number IS012103-1,A4. A second high pressure air supply conduit  54   a  from the air dryer  56  goes into the supply dust holding tank  60  and provides fluidization of the dust D, wherein fluidization of powder for dry coating painting is well known in the art and uniquely adapted in the present invention for use to fluidize the road dust D.  
         [0030]     The dust supply system  38  includes a pneumatic pump  62 , as for example Model 627LS manufactured by Nordson Corporation of Westlake, Ohio, which is connected to a third high pressure air supply conduit  54   b  from the air dryer  56 . The pump  62  extracts the fluidized dust D from supply dust holding tank  60  and then provides a pressurized mixture of compressed air and the dust CAD which then is sent along a high pressure dust supply conduit  54 D to four mutually spaced dust spray nozzles  64 , as for example an AeroCharge® powder spray gun of Nordson Corporation of Westlake, Ohio. Each spray nozzle  64  is preferably located under a respective air vent  50   a ,  50   b ,  50   c ,  50   d  of the air supply system  34 . The dust spray nozzles  64  are each mounted on twin swivel stands  70  which depend from the ceiling  16  and allow for three degrees of freedom of aiming of the dust spray nozzles. Each dust spray nozzle  66  has an exit orifice  68  which is generally oriented longitudinally (generally parallel to the length) of the dust testing chamber  12  such as to provide a cloud C of the dust D in the interior chamber space  121  which expands generally toward the center of the dust testing chamber, the cloud mixing with the processed air PA from the air supply system  34 .  
         [0031]     The aforementioned dust recapture system  40  provides for recirculation (recycling) of both the processed air PA and the dust D which have been introduced into the dust testing chamber  12  in the manner described hereinabove. As above described, the floor grating  28  is universally perforated so as to allow passage freely therethrough of the processed air and the dust PAD from the interior chamber space  121  into the plenum  30  and exit via the return ducts  32 . The negative air pressure to provide this evacuation is supplied by the aforementioned air flow system  34 , in particular the fan unit  42 , interfaced with the dust recapture system  40 , in that the return ducts  32  interface, via return ducting  72  to a return dust fluidizer  78  the air filtration unit  74 . In this regard, it is preferred for the air supply system  34  to provide an air pressure within the interior chamber space  121  which is below atmospheric pressure, as for example 0.1 inches of water so that all dust is kept therewithinin. The return dust fluidizer  78  includes a return dust holding tank (or bed)  80  which is interconnected with a fourth high pressure air supply conduit  54   c  goes between the air dryer  56  and the return dust holding tank  80  such that the dust D is fluidized with the compressed air, wherein fluidization of powder for dry coating painting is well known in the art and uniquely adapted in the present invention for use to fluidize the road dust D. The dust D is then extracted from the return dust holding tank in the form of a fluidic mixture of the compressed air and the dust CAD′, which is then transported along a second high pressure dust supply conduit  54 D′ to the supply dust holding tank  60 .  
         [0032]     In order to provide clean air recyclably to the fan unit  42 , the air filtration unit  74  is provided gravitationally above the return dust holding tank  80 . In this regard, dust D will accumulate in the return dust holding tank  80  either by directly falling thereinto, falling from the filter system  86  of the filtration unit  74 , or upon back pulse pressurization of the filters as discussed hereinbelow. A preferred filter system  86  is composed of 24 box filters, each being a Herding filter No. 1500/18.  
         [0033]     To perform dust investigations, a motor vehicle  24  is parked inside the dust testing chamber  12  (within the interior chamber space  12 I) and the interior vehicle space  24 I of the motor vehicle is then connected, via tubing  88  (for example a flexible 6 inch diameter tube for air evacuation and a one-half inch diameter tube for cabin pressure measurement) to a leak detection system  90 , as for example Model FD-TMM-400 of Flow Dynamics Corporation of Mesa, Ariz., through a portal  14   p  formed in a sidewall  14  of the dust testing chamber  12 . The leak detection system  90  is, for example, composed of a vacuum generating and leak detecting device  92  preceded upstream by a dust filter  94 . In this regard, the motor vehicle  24  is prepared by taping shut its body air inlet and inserting a window template in the driver&#39;s side front door window (which is in the down position). Electrostatic precipitators are placed in the rear seat and rear compartment to provide air borne dust measurement within the passenger compartment  241  of the motor vehicle.  
         [0034]     To facilitate the dust clouds C enveloping the motor vehicle  24  in a desired manner, a plurality of stand-alone fans  98  are preferably placed around the floor grating  28 , for example one stand-alone fan at each wheel well of the motor vehicle.  
         [0035]     Operation of the dust testing facility  10  will now be described with additional reference to  FIG. 7 , wherein it is seen that various sensor inputs  100  are processed according to a predetermined program by a microcontroller  102  with manual inputs, as for example a Model PanelView 550 of Allen-Bradley, Division of Rockwell Automation, Milwaukee, Wis., whereupon operation of the above described components  104  of the dust testing facility  10  are controlled. After placement of the motor vehicle into the dust testing chamber  12  and its preparation with the leak detection system  90 , as described above, the following sequence of events are typical.  
         [0036]     The leak detection system  90  is activated and a waiting period begins in order to ensure the pressure of the interior vehicle space  241  of the motor vehicle is at 0.5 inches of water negative pressure (vacuum) relative to atmospheric pressure (that is, 0.5 inches of water below atmospheric pressure). The stand-alone fans  98  are switched on (manually), the fan unit  42  is switch on and adjusted to provide about 6,000 cubic feet per minute of air flow, and the microprocessor  102  adjusts the air A via the heating and air conditioning and steam injection units  46 ,  48  so that it becomes processed air PA having 75 degrees Fahrenheit temperature and 50% relative humidity upon entry into the dust test chamber  12 . Further, the microprocessor  102  adjusts the air supply system  34  so that there is a 0.1 inch of water of negative (vacuum) pressure relative to atmospheric in the interior chamber space  121  of the dust testing chamber  12 . The dust fluidizers  58 ,  78  are activated. This warm-up phase of the operation typically lasts about 15 minutes.  
         [0037]     The pump  62  is then activated, whereupon the dust D is emitted from the dust spray nozzles  64  in the form of dust clouds C. This continues for a preferred eight minutes, which is the test phase of operation.  
         [0038]     At the conclusion of the test phase, the pump  62  is deactivated, stand-alone fans are turned off, the leak detection system  90  is turned off, and the dust fluidizers are deactivated; dust entry into the dust testing chamber  12  has now ceased. The fan unit  42  continues running for another twelve minutes, which is the cleaning phase of operation, to provide evacuation of the dust from the dust testing chamber  12 .  
         [0039]     At the end of the cleaning phase, the dust evaluation phase commences. With the fan unit still running, the hinged personnel access door  20   a  is opened and the leak detection system  90  disconnected from the motor vehicle, and the electrostatic precipitators are removed from the interior vehicle space of the motor vehicle  24  and then weighed to ascertain the amount of dust collected thereinside during the test phase. The exterior of the motor vehicle is cleaned of dust while still in the dust testing chamber  12  and the fan unit is still running. The fan unit is now shut down and the roll-up door is opened, the vehicle is removed from the dust testing chamber  12  and visually inspected for all locations of dust entry, as for example around the door seals.  
         [0040]     In order to recapture as much of the dust as possible for recirculation, the microprocessor selectively uses a fifth high pressure air conduit  54   c  during the cleaning phase of operation to supply pulsating back pressure to the filter system  86 , the air pulsations causing the box filters of the filtration unit to flutter and thereby purge dust clinging to the filter system to the return dust holding tank  80 .  
         [0041]     As can be understood from the foregoing, the dust testing facility according to the present invention has the advantage of providing motor vehicle dust testing to be conducted year round and independent of external weather conditions by virtue of the dust test chamber&#39;s ability to self-regulate temperature and humidity.  
         [0042]     To those skilled in the art to which this invention appertains, the above described preferred embodiment may be subject to change or modification. Such change or modification can be carried out without departing from the scope of the invention, which is intended to be limited only by the scope of the appended claims.