Patent Publication Number: US-2004052683-A1

Title: Portable vehicle exhaust analyzer module

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
     [0001] The present application claims priority from co-pending provisional U.S. Patent Application Serial No. 60/385,556, filed Jun. 5, 2002, which is incorporated herein by reference in its entirety. 
    
    
     
       FIELD OF THE DISCLOSURE  
       [0002] The present disclosure generally relates to motor vehicle maintenance equipment and methods and, more specifically, to a portable vehicle exhaust analyzer module.  
       BACKGROUND OF THE DISCLOSURE  
       [0003] Due to government regulations, testing of vehicle exhaust emissions for compliance with minimum standards has become a necessary function for testing facilities and repair garages. Originally, only hydrocarbons and carbon monoxide had to be measured, but stricter standards have added oxygen and carbon dioxide, and still stricter regulations require oxides of nitrogen to be measured as well for compliance with statutory requirements. If a vehicle fails an emission test, it must be repaired. In the repair process, a mechanic must be able to tell whether the repairs have affected the content of the exhaust gas that was at an unacceptable level during the emission test. Therefore, there is a need for a vehicle sensor assembly that can be used by repair technicians to determine whether their repairs have remedied emission test failures.  
       [0004] Large platform engine analyzers were initially developed to measure gases emitted in vehicle exhaust. These platform engine analyzers were large devices that were transported by wheeling them around on a large cart. These large engine analyzers are typically utilized by government agencies to perform actual emission tests on vehicles, but their size and considerable expense make them difficult for smaller repair garages to own.  
       [0005] “Portable” exhaust sensor assemblys were subsequently developed to be used for repair purposes. One example of a hand-held vehicle exhaust analyzer in shown in U.S. Pat. No. 6,287,519 to Norman et al. The vehicle exhaust analyzer is of a size and weight to be held in a user&#39;s hands. The system includes a housing with an inlet receiving exhaust emitted from the vehicle. A sensor assembly is disposed in the housing, receives the exhaust emitted from the vehicle through the inlet, and determines the content of a plurality of different gases in the exhaust. A control system is disposed in the housing and is operatively coupled with the sensor assembly to regulate operations of the sensor assembly and to receive and interpret results of operations of the sensor assembly. A power supplying apparatus is disposed in the housing to deliver power throughout the system. The housing, and all components disposed in the housing have a combined weight of no greater than about five pounds.  
       [0006] The vehicle exhaust analyzer shown in U.S. Pat. No. 6,287,519 to Norman et al. uses a multiple-gas non-dispersive infrared (NDIR) sensor assembly that is shown in U.S. Pat. No. 5,811,812 to Williams et al. The sensor assembly includes a pump assembly, a infrared source, a sample tube, an optical block, a nitrous oxide (NOx) sensor, and an oxygen (O 2 ) sensor.  
       [0007] What is still desired is a new and improved vehicle exhaust analyzer module. Preferably, the module will include a simple, light-weight, compact and rugged design, which is of a size and weight to be picked up and carried easily by a user, while still performing the same functions of sampling and sensing gas content in vehicle exhaust as previous exhaust analyzers.  
       SUMMARY OF THE DISCLOSURE  
       [0008] The present disclosure provides a vehicle exhaust analyzer module including a housing enclosure having symmetrical portions secured together, a support shelf supported within the housing enclosure, a gas inlet for directing gaseous vehicle exhaust into the housing enclosure, a sensor assembly positioned on the support shelf for receiving the gaseous vehicle exhaust and providing an analysis of the gaseous vehicle exhaust, circuitry for controlling the sensor assembly, and a signal output connector coupled to the control circuitry for outputting a signal representing an analysis result of the sensor assembly.  
       [0009] Among other benefits and features, the present disclosure provides a new and improved vehicle exhaust analyzer module that includes a simple, light-weight, compact and rugged design, which is of a size and weight to be picked up and carried easily by a user, while still performing the same functions of sampling and sensing gas content in vehicle exhaust as previous exhaust sensor analyzers.  
       [0010] According to one aspect of the present disclosure, the symmetrical portions of the housing enclosure form an internal wall supporting the support shelf. According to another aspect, the housing enclosure is made from plastic. According to an additional aspect, the housing enclosure includes a handle for lifting and carrying the module. According to a further aspect, the symmetrical portions of the housing enclosure are secured together with screws.  
       [0011] According to another aspect of the present disclosure, the module has a weight of not more than about eleven pounds. According to an additional aspect, the housing enclosure has dimensions of not more than about 14 inches long by about 9 inches tall by about 8 inches wide.  
       [0012] According to an additional aspect of the present disclosure, a battery is positioned within the housing enclosure and connected to the control circuitry. According to a further aspect, the battery is rechargeable. According to yet another aspect, a power supplying apparatus is positioned within the housing enclosure, and connected to the control circuitry, and connectable to a cigarette lighter receptacle of a vehicle under test or a wall outlet charger.  
       [0013] According to a further aspect of the present disclosure, the module includes a filter assembly for filtering gaseous vehicle exhaust prior to the gaseous vehicle exhaust entering the gas inlet of the housing enclosure. According to a still another aspect, a sensor is provided within the filter assembly and connected to the control circuitry, for sensing if the filter assembly is filled with water. According to yet an additional aspect, the control circuitry is programmed to stop operation of the sensor assembly upon receiving a signal from the sensor indicating that the filter assembly, which normally is self-draining, is filled with water.  
       [0014] According to another aspect of the present disclosure, the module includes a gas outlet for releasing gaseous vehicle exhaust from the housing enclosure, and a sensor positioned in the gas outlet and connected to the control circuitry, for sensing if an external line is connected to the gas outlet. According to an additional aspect, the control circuitry is programmed to stop operation of the sensor assembly upon receiving a signal from the sensor indicating that an external line is not connected to the gas outlet.  
       [0015] According to still another aspect of the present disclosure, the support shelf includes a base plate and end walls extending upwardly from opposing ends of the base plate, the housing enclosure includes open ends closed by the end walls of the support shelf, and the end walls of the support shelf are received in circumferential grooves of the open ends of the housing enclosure. According to a further aspect, all components of the module other than the housing enclosure and the battery are mounted on the support shelf. According to an additional aspect, the housing enclosure includes a bottom panel having drain holes for draining internally leaked water from the module.  
       [0016] Additional aspects and advantages of the present disclosure will become readily apparent to those skilled in this art from the following detailed description, wherein only an exemplary embodiment of the present disclosure is shown and described, simply by way of illustration of the best mode contemplated for carrying out the present disclosure. As will be realized, the present disclosure is capable of other and different embodiments, and its several details are capable of modifications in various obvious respects, all without departing from the disclosure. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0017] Reference is made to the attached drawings, wherein elements having the same reference character designations represent like elements throughout, and wherein:  
     [0018]FIG. 1 is an end, side and top perspective view of an exemplary embodiment of an exhaust analyzer module constructed in accordance with the present disclosure;  
     [0019]FIG. 2 is an opposite end, side and top perspective view of the exhaust analyzer module of FIG. 1;  
     [0020]FIG. 3 is an end, opposite side and bottom perspective view of the exhaust analyzer module of FIG. 1;  
     [0021]FIG. 4 is an end, opposite side and top perspective view of the exhaust analyzer module of FIG. 1;  
     [0022]FIG. 5 is an exploded end, opposite side and top perspective view of the exhaust analyzer module of FIG. 1;  
     [0023]FIG. 6 is an end and bottom perspective view of one of two identical body portions of the exhaust analyzer module of FIG. 1, wherein the body portion is shown lying on a side thereof;  
     [0024]FIG. 7 is an end and top perspective view of the body portion of the exhaust analyzer module of FIG. 1, wherein the body portion is shown lying on a side thereof;  
     [0025]FIG. 8 is an end and top perspective view of the body portion of the exhaust analyzer module of FIG. 1;  
     [0026]FIG. 9 is an end and side perspective view of the body portion of the exhaust analyzer module of FIG. 1; and  
     [0027]FIG. 10 is an end, side and top perspective view of the exhaust analyzer module of FIG. 1 shown with connectors, a filter assembly and a sample exhaust gas hose. 
    
    
     DETAILED DESCRIPTION OF THE DISCLOSURE  
     [0028]FIGS. 1 through 5 and FIG. 10 show an exemplary embodiment of a portable vehicle exhaust analyzer module  10  constructed in accordance with the present disclosure. In general, the exhaust analyzer module  10  is used for the measurement of vehicle exhaust gases including carbon monoxide, hydrocarbons, carbon dioxide, oxygen, and oxides of nitrogen. The module  10  accepts exhaust gas samples from a vehicle under test and contains a sensor assembly  12  (as shown in FIG. 5) that provides measurements of the contents of the gas sample to a remote computer (not shown), such as a pocket personal computer, laptop or desktop computer, or a specialty computer such as the MODiS™ modular diagnostic information system available from Snap-On Incorporated of Kenosha, Wis. Software including a vehicle exhaust diagnostic program is loaded on the remote computer for allowing a technician to utilize the measurements produced by the module  10  to determine the contents of the vehicle exhaust.  
     [0029] As shown best in FIG. 5, the module  10  includes a housing enclosure  14  having two symmetrical portions  16  secured together, a support shelf  18  supported within the housing enclosure  14 , and an exhaust gas inlet  20  for directing gaseous vehicle exhaust into the module  10 . The sensor assembly  12 , which is positioned on the support shelf  18 , receives the gaseous vehicle exhaust and provides an analysis of the contents of the gaseous vehicle exhaust. Control circuitry is mounted on a controller PCB  22  for controlling the sensor assembly  12 , and a signal output connector  66  is coupled to the control circuitry of the controller PCB  22  for outputting (to a remote computer) a signal representing an analysis result of the sensor assembly  12 .  
     [0030] Among other benefits and features, the present disclosure provides a new and improved vehicle exhaust analyzer module  10  that includes a simple, light-weight, compact and rugged design, which is of a size and weight to be picked up and carried easily by a user, while still performing the same functions of sampling and sensing gas content in vehicle exhaust as previous exhaust sensor analyzers. The module  10  also includes provisions for mounting a handheld pocket personal computer, PDA or Palm type PDA, directly on to the side of the module  10  for easy, convenient access and storage.  
     [0031] The housing enclosure  14  is preferably injection molded from a plastic, in order to provide sufficient strength with minimal weight. The module  10  is preferably about 14 inches long by 9 inches high, and about 8 inches wide, and the module  10  weighs about 11 pounds, so that it can be easily picked up and carried by a user. The housing enclosure  14  includes a handle  24  for lifting and carrying the module  10 . As shown best in FIG. 5, the symmetrical portions  16  of the housing enclosure  14  are secured together with various screws  26 ,  28 ,  30  according to one exemplary embodiment of the present disclosure.  
     [0032]FIGS. 6 through 9 show one of the symmetrical portions  16  of the housing enclosure  14 . FIG. 5 shows both of the symmetrical portions  16  of the housing enclosure. Each symmetrical portion  16  includes a ledge  32 , which together form an internal wall supporting the support shelf  18 . As shown in FIGS. 5 through 8, the symmetrical portions  16  of the housing enclosure  14  can also each include notches  34  in a bottom panel  36  which form drain holes in the assembled housing enclosure  14  as shown in FIG. 3. The drain holes  34  allow water to exit the module  10  upon an internal leak occurring within the module. The ledges  32  also include notches  38  which align with the notches  34  in the bottom panel  36  to aid drainage.  
     [0033] The support shelf  18  includes a base plate  40  and first and second end walls  42 ,  44  extending upwardly from opposing ends of the base plate  40 . Open ends  46 ,  48  of the assembled housing enclosure  14  are closed by the end walls  42 ,  44  of the support shelf  18 . The symmetrical portions  16  of the housing enclosure  14  each include circumferential grooves  49 , as best shown in FIGS. 6 through 8, that receive edges of the end walls  42 ,  44  of the support shelf  18  upon the housing enclosure  14  being assembled around the support shelf  42 ,  44 .  
     [0034] The sensor assembly  12  is shown in FIG. 5 and may preferably be a gas bench such as manufactured by Andros, Incorporated of Berkeley, Calif., and includes pump assembly  50 , infrared source  52 , sample tube  54 , optical block  56 , nitrous oxide sensor (not viewable), and oxygen sensor (not viewable). The control circuitry of the controller PCB  22  is connected to and controls the sensor assembly  12 . During operation, exhaust is received into the sensor assembly  12  and delivered into the sample tube  54  by the pump assembly  50 . While the exhaust is in the sample tube  54 , the infrared source  52  generates infrared light which travels through the exhaust in the sample tube  54 , and is reflected into the optical block  56 . The content of various gases (such as carbon monoxide, carbon dioxide, and hydrocarbons) can be determined by the response of different wavelengths of infrared light as they pass through the exhaust, as is known in the art. Exhaust then passes into the nitrous oxide sensor and the oxygen sensor, which are chemical sensors operable to determine the content of the respective gases in the exhaust. In this way, the content of five gases (as required in many government emissions programs) in exhaust emitted from a vehicle is determined. Exhaust then exits the sensor assembly  12  and is eventually released from the module  10  through an exhaust gas outlet  58 .  
     [0035] Operation of a similar sensor assembly is described in greater detail in U.S. Pat. No. 5,811,812 to Williams et al., which is incorporated herein by reference. U.S. Pat. No. 5,811,812 to Williams et al. is assigned to Andros, Incorporated of Berkeley, Calif., and shows a multiple-gas non-dispersive infrared (NDIR) sensor assembly.  
     [0036] The sensor assembly  12  has a weight such that the weight of the entire analyzer module  10  does not exceed about eleven pounds. The sensor assembly  12  preferably operates at ambient temperature, so that the housing enclosure  14  of the analyzer module  10  can be composed of a light-weight plastic material. The sensor assembly  12  and the pump assembly  50  are also designed to draw a small amount of power (preferably about 10 watts), so as not to require a large power supply which would destroy the portability of the analyzer module  10 . The sensor assembly  12  preferably has a sample rate of about seven liters per minute.  
     [0037] A battery  60  is positioned within the housing enclosure and connected to the control circuitry of the controller PCB  22 . Preferably, the battery  60  is rechargeable and, as shown best in FIG. 2, the module  10  includes a power inlet plug  64  for recharging the battery. The module  10  also includes a power outlet plug  62  so that the battery  60  can be used to power a remote computer used with the module  10 . Alternatively, power can be provided to the analyzer module  10  through the power inlet plug  64  by either cigarette lighter receptacle in vehicle being tested, or by a standard wall outlet. 12-volt DC power is routed through the inlet power plug to analyzer module  10 , which also results in the battery  60  being charged through the controller PCB  22 .  
     [0038] The battery  60  is positioned within the housing enclosure  14  on the bottom panels  36  of the housing enclosure  14  below the ledges  32  supporting the support shelf  18 . All components of the module  10  other than the housing enclosure  14  and the battery  60  are mounted on the support shelf  18 .  
     [0039] As shown best in FIG. 2, the module  10  includes all electrical/data connectors mounted on the first end wall  42  of the support shelf  18 . The connectors includes the power inlet plug  64  and the power outlet plug  62 , and the signal output connector. The signal output connector comprises two DB9S connectors  66 ,  68 , and communication between the sensor assembly  12  and the external PC is in RS-232 format. A USB port  70  is also mounted in the end wall  42  and connected to the controller PCB  22 . Although not shown, the module  10  includes a clip attachable to a screw hole  72  in the end wall  42  for supporting an external wire connected to the USB port  70 . A connector  74  for receiving tachometer and oil temperature readings from the vehicle under test is secured to the end wall  42  and connected to the controller PCB  22 .  
     [0040] As shown best in FIG. 1, the module  10  includes all fluid connectors mounted on the second end wall  44  of the support shelf  18 . The fluid connectors includes the exhaust gas outlet  58 , a calibrating gas inlet  76 , the exhaust gas inlet  20  and a filtered fluid inlet  78 .  
     [0041] The module  10  includes a fan  80  for drawing air through the housing enclosure  34 . The fan  80  is connected to the control circuitry of the controller PCB  22 , and the control circuitry includes a thermometer and is programmed to operate the fan  80  so that a temperature within the housing enclosure  34  is regulated. In addition, in conjunction with the controller PCB  22  and the fan  80 , the internal battery  60  charge rate is regulated from a high rate to low, based on temperature, battery voltage and current by the controller PCB  22 . The fan  80  is mounted on the second end wall  44  of the support shelf  18  (as shown in FIG. 5, the fan  80  also includes a filter  82 ), and an air vent  84  is provided in the first end wall  42  to allow air to be drawn into the module  10  by the fan  80 .  
     [0042] As shown best in FIG. 10, the module  10  further includes a sample hose  86  for coupling a tailpipe of a vehicle under test to the module  10 , and a filter assembly  88  for filtering gaseous vehicle exhaust prior to the gaseous vehicle exhaust entering the module. The filter assembly  88  contains a hydrophilic filter operating to remove both dirt and moisture from the exhaust, and includes an inlet fitting nipple  90 , an outlet fitting nipple  92 , and a drain fitting nipple  94 . Preferably the module  10  includes a sensor (not shown) within the filter assembly  88  and connected to the control circuitry, for sensing if the filter assembly  88  becomes filled with water. The control circuitry is programmed to stop operation of the sensor assembly  12  upon receiving a signal from the sensor indicating that the filter assembly  88  is filled with water.  
     [0043] A hose  96  connects the outlet fitting nipple  92  of the filter assembly to the exhaust gas inlet  20 , and a hose  98  connects the drain fitting nipple  94  to the filtered fluid inlet  78 . A nipple  100  is mounted in the calibrating gas inlet  76 . A connector  102  is fitted in the exhaust gas outlet  58  and a sensor (not shown) is positioned in the connector  102  and connected to the control circuitry, for sensing if an external line is connected to the gas outlet  58 . The control circuitry is programmed to stop operation of the sensor assembly  12  upon receiving a signal from the sensor indicating that an external line is not connected to the gas outlet (to ensure that the vehicle exhaust is properly disposed).  
     [0044] In operation, a user manually couples a distal end of the sample hose/probe  86  to a tailpipe of vehicle. Exhaust from tail pipe travels through sample hose/probe  86  and the filter assembly  88 . The filter assembly  88  operates to filter dirt and condensation from the exhaust. The filtered exhaust then travels into the sensor assembly  12  though the exhaust gas inlet  20 , where the content of carbon monoxide, carbon dioxide and hydrocarbons is determined. The pump  50  of the sensor assembly  12  then advances the exhaust through the nitric oxide sensor and the oxygen sensor of the sensor assembly. Exhaust then exits the analyzer module  10  through the exhaust gas outlet  58 .  
     [0045] When an external PC is coupled to the analyzer module  10  via DB9S connectors, the sensor assembly  12  communicates directly with the external PC. Signal conditioning, formatting, and other software operations are performed by the external PC, so that data from sensor assembly can be interpreted and converted into useable values for vehicle diagnostics. Because of the vast memory available for storing and executing software, and potentially superior display capabilities, it may be desirable to utilize an external PC to analyze and/or display real-time parameters sensed by sensor assembly  12 .  
     [0046] Thus, the present disclosure provides a new and improved vehicle exhaust analyzer module  10 . The exemplary embodiment described in this specification has been presented by way of illustration rather than limitation, and various modifications, combinations and substitutions may be effected by those skilled in the art without departure either in spirit or scope from this disclosure in its broader aspects and as set forth in the appended claims. The vehicle exhaust analyzer module  10  disclosed herein, and all elements thereof, are contained within the scope of at least one of the following claims. No elements of the presently disclosed vehicle exhaust analyzer module  10  are meant to be disclaimed.