Patent Publication Number: US-7717094-B2

Title: Canister arrangement in power generating apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   The present application is based on and claims priority under 35 U.S.C. 119 to Japanese Patent Application No. 2007-116076, filed on Apr. 25, 2007, the entire contents of which is hereby incorporated by reference and should be considered part of this specification. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a power generating apparatus and more particularly to an arrangement of a canister containing an adsorbent for adsorbing thereonto fuel that evaporates from an engine fuel tank of the power generating apparatus. 
   2. Description of the Related Art 
   A conventional power generating device having a canister containing the evaporative fuel adsorbent is described in Japanese Publication No. JP-7-34985. The device described in JP 7-34985 includes an engine, a fuel tank for storing fuel to be supplied to the engine, and a canister containing an adsorbent for adsorbing thereonto fuel that evaporates from the fuel tank. The canister includes a communicating tube, which places the canister in communication with the atmosphere. The canister is also in communication with an intake system of the engine. 
   The engine is driven by fuel supplied from the fuel tank and outputs a motive force of a predetermined magnitude. During the course of this operation, as described above, the adsorbent and the canister containing the adsorbent therein generally work as follows. Evaporative fuel (e.g., fuel vapor) is roughly constantly produced in the fuel tank. During a period in which the engine is stopped or in a low-speed range of operation (e.g., idling), most of the evaporative fuel is adsorbed by the adsorbent, thereby inhibiting release of the evaporative fuel into the atmosphere. 
   When the engine is in a medium-speed or high-speed range of operation, a negative pressure builds up inside the intake system of the engine. The negative pressure causes atmospheric air to be sucked into the canister through the communicating tube of the canister. The evaporative fuel that is evaporated from the fuel tank and is flowing toward the canister is sucked with the air, which is sucked into the canister through the communicating tube, into the intake system and supplied to the engine, where it is subjected to combustion. The evaporative fuel that has been adsorbed onto the adsorbent is purged from the adsorbent by the air sucked through the communicating tube into the canister, and subjected to combustion as described above. 
   The power generating apparatus has a frame and the engine is provided inside the frame to drive the generator. However, some power generating apparatuses do not include the adsorbent and a canister containing the adsorbent therein. When the canister containing the adsorbent therein is simply added to such a power generating apparatus, the power generating apparatus can be increased in size, which is undesirable, in particular, for a portable power generating apparatus. 
   To prevent the power generating apparatus from being increased in size, for example, positioning the canister adjacent to the air cleaner included in the intake system of the engine to thereby attain a compact arrangement is conceivable. However, such an arrangement can cause inconvenience in that the canister obstructs maintenance of an element or the like in the air cleaner. 
   SUMMARY OF THE INVENTION 
   In view of the circumstances noted above, one aspect of the present invention is to prevent the power generating apparatus from being increased in size when a canister containing an adsorbent therein is added to the power generating apparatus. 
   Another aspect of the present invention is to facilitate maintenance of component parts of an engine even when the canister is added to the power generating apparatus without an increase of the power generating apparatus in size. 
   In accordance with one aspect of the present invention, a power generating apparatus is provided, comprising a frame, an engine disposed inside the frame and configured to drive a generator, the engine including an intake system, and a fuel tank for storing fuel to be supplied to the engine. The power generating apparatus also comprises a canister containing an adsorbent configured to adsorb thereonto fuel vapor from the fuel tank, the canister comprising a communicating tube configured to communicate the canister with the atmosphere, the canister further in communication with the intake system, the canister being positioned at least partially in a space between the frame and the intake system. 
   In accordance with another embodiment, a power generating apparatus is provided, comprising a frame, an engine attached to the frame and configured to drive a generator, the engine including an intake system, and a fuel tank for storing fuel to be supplied to the engine. The power generating apparatus further comprises a canister containing an adsorbent configured to adsorb thereonto fuel vapor from the fuel tank, the canister comprising a communicating tube configured to communicate the canister with the atmosphere, the canister further in communication with the intake system, and means for movably positioning the canister into and out of a space between the frame and the intake system to facilitate maintenance of the intake system. 
   In accordance with still another aspect of the present invention, a method for operating a power generating apparatus is provided, wherein the power generating apparatus has a frame, an engine disposed inside the frame, the engine including an intake system and configured to drive a generator, a fuel tank for supplying fuel to the engine and a canister containing an adsorbent for adsorbing fuel vapor from the fuel tank, the canister movably attached to the frame. The method comprises positioning the canister in a space between the frame and the intake system so that at least part of the canister is disposed in said space, pivoting the canister out of said space and outwardly from the frame, accessing the intake system through said space to perform maintenance thereon, and pivoting the canister into said space between the frame and the intake system when said maintenance is complete. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     These and other features, aspects and advantages of the present invention will now be described in connection with preferred embodiments of the invention, in reference to the accompanying drawings. The illustrated embodiments, however, are merely examples and are not intended to limit the invention. The drawings include the following 6 figures. 
       FIG. 1  is a side view of one embodiment of a power generating apparatus. 
       FIG. 2  is a general block diagram of the power generating apparatus. 
       FIG. 3  is a rear view of the power generating apparatus. 
       FIG. 4  is a plan view of the power generating apparatus. 
       FIG. 5  is a partially-enlarged cross-sectional view of  FIG. 1 . 
       FIG. 6  is a partially-enlarged cross-sectional view of  FIG. 4 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   In the following detailed description, terms of orientation such as “front,” “rear,” “left” and “right” are used herein to simplify the description of the context of the illustrated embodiments. Likewise, terms of sequence, such as “first” and “second,” are used to simplify the description of the illustrated embodiments. Because other orientations and sequences are possible, however, the present invention should not be limited to the illustrated orientation. Those skilled in the art will appreciate that other orientations of the various components described above are possible. 
   Embodiments of the present invention relate to a canister arrangement in a power generating apparatus and aims at inhibiting the power generating apparatus from being increased in size when a canister containing an adsorbent is added to the power generating apparatus. 
   The power generating apparatus can have a frame, an engine provided inside the frame to drive a generator, a fuel tank for storing fuel to be supplied to the engine, and a canister containing an adsorbent for adsorbing thereonto fuel that evaporates from the fuel tank. The canister can include a communicating tube, to place the canister in communication with the atmosphere. The canister can also be in communication with an intake system of the engine. In one embodiment, the canister is positioned in a space between the frame and the intake system. 
   Reference numeral  1  in the drawings denotes a portable power generating apparatus. For clarity, in the following descriptions, a direction indicated by arrow Fr in the drawings is a forward direction of the apparatus. 
   The power generating apparatus  1  can include a frame  2  that can be placed on a working surface such as the ground or a floor surface. The frame  2  can include a chassis  3  that forms a lower end of the frame  2 , a pair of front and rear upwardly-projecting handles  4  supported by front and rear ends of the chassis  3 , respectively, and a pair of left and right connecting bars  5  forming left and right ends of the frame  2 , respectively, and supported by the front and rear handles  4  thereacross. The handles  4  can be formed by bending a circular pipe  4   a  into an inverted U-shape. 
   An engine  9  (e.g., a four-cylinder engine) for driving generator  8  (e.g., an alternating current generator) can be mounted inside the frame  2  and supported by the chassis  3 . The engine  9  includes an engine body  10  that outputs a driving force, an intake system  14  for supplying an air-fuel mixture  13  of air  11  and fuel  12  to the engine body  10 , and an exhaust system  16  for exhausting combustion gas, which is a resultant product of combustion of the air-fuel mixture  13  in the engine body  10 , to the atmosphere. 
   The engine body  10  can include a crankcase  20  supporting a crankshaft  19 , a cylinder  21  formed on the crankcase  20  (e.g., in an upright orientation), a piston  22  axially slidably inserted into the cylinder  21 , an interlocking rod  23  for interlocking between the crankshaft  19  and the piston  22 , an intake valve  26  and an exhaust valve  27  for selectively opening and closing a first intake passage  24  and a first exhaust passage  25  formed in a projecting end of the cylinder  21 , respectively, and a valve actuating mechanism (not shown) for selectively closing the intake and exhaust valves  26  and  27  housed in a valve actuating chamber  28  defined in the projecting end of the cylinder  21 . The engine body  10  also includes a spark plug  31  with a discharging unit thereof facing a combustion chamber  30  inside the cylinder  21 . 
   The intake system  14  can include a carburetor  35 , an intake pipe  36 , and an air cleaner  37 , connected in series with the first intake passage  24 . A space inside the carburetor  35 , the intake pipe  36 , and the air cleaner  37  defines a second intake passage  38 , which is in communication with the first intake passage  24 . The carburetor  35  can include a throttle valve  40  for adjusting an opening of the second intake passage  38 , an actuator  41  serving, for example, as a step motor for actuating the throttle valve  40 , a choke valve  42  for adjusting an opening of the second intake passage  38  at a position upstream of the throttle valve  40 , and an actuator  42  serving, for example, as a step motor for actuating the choke valve  42 . 
   The air cleaner  37  can include a cleaner casing  44  forming an outer shell of the air cleaner  37 . The cleaner casing  44  can be fixed to the engine  9  on a side close to the carburetor  35  with at least one fastener  44   a . The cleaner casing  44  can include a cleaner casing body  44   c , a cleaner casing cover  44   d , and at least one fastener  44   e . An air inlet port  44   d , through which the outside air  11  is introduced into the cleanser casing  44 , can be defined in the cleaner casing body  44   c . The cleaner casing cover  44   d  can releasably close the cleaner casing  44 . The cleaner casing cover  44   d  can be removably fixed to the cleaner casing body  44   c  with the fastener  44   e . An element  37   a  can be housed in the cleaner casing body  44   c.    
   The exhaust system  16  can include an exhaust pipe  45  and a muffler  46 , connected in series with the first exhaust passage  25 . A space inside the exhaust pipe  45  and the muffler  46  is defined as a second exhaust passage  47 , which is in communication with the first exhaust passage  25 . 
   A fuel tank  50  for storing fuel  12  to be supplied to the engine  9  through the carburetor  35  can be provided above the engine  9  in the vicinity thereof. An adsorbent  52  for adsorbing thereonto evaporative fuel  51  (e.g., fuel vapor) produced in the fuel  12  in the fuel tank  50 , and a canister  53  containing the adsorbent  52  therein are provided. In the illustrated embodiment, the adsorbent  52  is activated carbon. However, in other embodiments the absorbent can be other suitable materials. The canister  53  can be made of a resin and formed into a box shape of a rectangular cross section, and can be situated such that its long sides extend vertically. The canister  53  can be positioned in a vertically-elongated space S between one of the vertically-extending handles  4 , formed with the pipe  4   a  of the frame  2 , and the air cleaner  37  of the intake system  14 . In the illustrated embodiment, substantially the entire canister  53  is positioned inside the frame  2 . 
   The canister  53  can include, in its bottom, a communicating tube  54  which places the canister  53  in communication with the atmosphere. A first communicating passage  57 , through which an upper end of the fuel tank  50  is in communication with an upper end of the canister  53 , can be provided. A second communicating passage  58 , through which the upper end of the canister  53  is in communication with the air cleaner  37  of the intake system  14 , can also be provided. A blow-by gas passage  59 , through which the valve actuating chamber  28  is in communication with the air cleaner  37  of the intake system  14 , can also be provided. Each of the passages  57  to  59  can be formed of an elastic rubber hose, though other suitable materials can be used in other embodiments. 
   The canister  53  can be positioned to face an outer surface of the cleaner casing cover  44   d  of the cleaner casing  44  of the air cleaner  37 . The canister  53  can be supported via a pivot support  61  by the handle  4  formed with the pipe  4   a  of the frame  2  such that the canister  53  is capable of pivoting movement A (see  FIG. 4 ) away from the air cleaner  37  and the space S as well as outward with respect to the frame  2  and pivoting movement B (see  FIG. 4 ) in a reverse direction of that of the pivoting movement A. 
   The pivot support  61  can include a pivot support piece  63  and at least one fastener  64 . The pivot support piece  63  can attach to (e.g., clamp) the pipe  4   a  with a U-shaped first end, and supports the canister  53  at a second end with at least one fastener  62 . The fastener  64  can be screwed into the U-shaped end of the pivot support piece  63  to thereby adjust a coupling force (e.g., clamping pressure) applied on the pipe  4   a  from the first end. 
   When the fastener  64  is screwed up, the clamping pressure increases to fix the canister  53  to the pipe  4   a  with the pivot support  61 . On the contrary, when the fastener  64  is screwed down, the clamping pressure decreases. Accordingly, the canister  53  and the pivot support piece  63  of the pivot support  61  are integrally allowed to perform the pivoting movements A and B about the pipe  4   a . Meanwhile, during the course in which the canister  53  performs the pivoting movements A and B, the hoses forming the passages  57  and  59  are each deformed so that the canister  53  performs the pivoting movements A and B smoothly (e.g., in an unconstrained manner). 
   The power generating apparatus  1  can include a starter motor  65  for starting the engine  9 , an ignition unit  66  for causing the spark plug  31  to electrically discharge as required, a temperature sensor  67  for detecting a temperature of the engine body  10  of the engine  9 , and an engine speed sensor  68  for detecting the number of revolutions of the crankshaft  19  in the engine body  10  of the engine  9 . 
   The power generating apparatus  1  can further include a controller  69 , a battery  70 , main switch  71 , and a starter switch  72 . The controller  69  can electronically control the actuators  41  and  43 , and the ignition unit  66  based on detection signals supplied from the temperature sensor  67  and the engine speed sensor  68 . The battery  70  can be charged with a portion of electric power generated by the generator  8  through the controller  69 , and supplies electric power to the actuators  41  and  43 , the ignition unit  66 , and the like. The main switch  71  switches on and off power supply from the battery  70  to the starter motor  65 , the controller  69 , and the like. The starter switch  72  switches on and off power supply from the battery  70  to the starter motor  65  through the main switch  71 . The controller  69  includes an outlet  74  through which the other portion of the electric power generated by the generator  8  is output to an outside load  73 . 
   When the engine  9  is driven under control of the controller  69 , the outside air  11  is sucked toward inside the engine  9  through the intake system  14 . The carburetor  35  mixes the fuel  12  with the thus-sucked air  11  to produce the air-fuel mixture  13 . The air-fuel mixture  13  is subjected to combustion in the engine  9 . Combustion gas, which is a resultant product of the combustion in the engine  9 , is exhausted as the exhaust  15  through the exhaust system  16  to the outside. The engine  9 , which is caused to continuously drive as described above, drives the generator  8  to output electric power. The electric power can be output to the load  73  through the outlet  74  of the controller  69 . 
   During the above operation, the adsorbent  52  and the canister  53  work as follows. Fuel vapor  51  is roughly constantly produced in the fuel tank  51 . When the engine  9  is stopped or in a low-speed range of operation (e.g., idling), most of the fuel vapor  51  is adsorbed by the adsorbent  52  through the first communicating passage  57 , thereby inhibiting the fuel vapor  51  from being released into the atmosphere. 
   When the engine  9  is in a medium-speed or high-speed range of operation, a negative pressure builds up inside the intake system  14 . The negative pressure causes the air  76  to be sucked into the canister  53  from the outside through the communicating tube  54  of the canister  53 . The fuel vapor  51  that is evaporated from the fuel tank  50  and is flowing toward the canister  53  is sucked with the air  76 , which is sucked into the canister  53  through the communicating tube  54 , into the air cleaner  37  of the intake system  14  through the second communicating passage  58  and supplied to the engine  9 , where it is subjected to combustion. The fuel vapor  51  that has been adsorbed onto the adsorbent  52  is purged from the adsorbent  52  by the air  76  sucked through the communicating tube  54  into the canister  53 , and subjected to combustion in the engine  9  as in the above case. 
   During period in which the engine  9  is driving, blow-by gas  77  generated in the valve actuating chamber  28  is sucked into the air cleaner  37  of the intake system  14  and supplied to the engine  9  therefrom, then subjected to combustion. 
   According to the arrangement in the illustrated embodiment, the canister  53  is positioned in the space S between the frame  2  and the intake system  14 . 
   This arrangement inhibits, the canister  53  from projecting outward of the frame  2  when the canister  53  containing the adsorbent  52  is added to the power generating apparatus  1 , thereby inhibiting an increase of the engine  9  and power generating apparatus  1  in size. 
   Furthermore, as described above, the canister  53  can be positioned between the frame  2  and the intake system  14 , which places the canister  53  adjacent to the intake system  14 . This arrangement allows, when the canister  53  is to be brought into communication with the intake system  14  through the second communicating passage  58  as described above, to reduce the length of the second communicating passage  58  and the like, thereby reducing the size of the structure (e.g., a compact structure) for placing the canister  53  in communication with the intake system  14 . Thus, even when the canister  53  is added to the power generating apparatus  1  and placed in communication with the intake system  14 , an increase of the power generating apparatus  1  in size is prevented. 
   Meanwhile, the communicating tube  54  can be provided in the bottom of the canister  53 . 
   When the adsorbent  52  is used over a long period of time, water  78  is likely to accumulate in the canister  53  containing the adsorbent  52  therein. According to the arrangement in the illustrated embodiment, thus-accumulated water  78  is discharged downwardly of the canister  53  smoothly and without fail through the communicating tube  54  provided in the bottom of the canister  53 . Accordingly, performance of the adsorbent  52  is delivered without being inhibited by the water  78 . This further facilitates the maintenance of the adsorbent  52 . 
   Furthermore, as described above, the intake system  14  can include the air cleaner  37 , and the canister  53  is supported by the frame  2  such that the canister  53  is capable of the pivoting movement A away from the air cleaner  37  as well as outward with respect to the frame  2  and the pivoting movement B in its reverse direction. 
   Accordingly, maintenance work on the air cleaner  37  can be performed by screwing down the fastener  64  and causing the canister  53  to perform the pivoting movement A outward of the frame  2  integrally with the pivot support piece  63  of the pivot support  61  (indicated by long dashed double-short dashed lines in  FIGS. 4 and 6 ). When the canister  53  is caused to pivot as described above, the canister  53  is separated from an area where the canister  53  faces the cleaner casing cover  44   d  of the cleaner casing  44  of the air cleaner  37 , thereby providing access to the space S between the frame  2  and the intake system  14 . 
   Thus utilizing the space S facilitates maintenance work on the air cleaner  37 . For example, the element  37   a  in the cleaner casing body  44   c  can be replaced with a new one with the cleaner casing cover  44   d  separated from the cleaner casing body  44   c  (the long dashed double-short dashed lines in  FIG. 4 ). 
   As described above, the canister  53  is pivotally supported by the frame  2  by utilizing the pipe  4   a  which forms the frame  2 . This advantageously simplifies the pivotal support structure of the canister  53 . 
   The above descriptions have been made based on the drawings. However, substantially the entire canister  53  is not necessarily positioned inside the frame  2 . Alternatively, the canister  53  may be only partially positioned inside the frame  2 . 
   Although these inventions have been disclosed in the context of a certain preferred embodiments and examples, it will be understood by those skilled in the art that the present inventions extend beyond the specifically disclosed embodiments to other alternative embodiments and/or uses of the inventions and obvious modifications and equivalents thereof. In addition, while a number of variations of the inventions have been shown and described in detail, other modifications, which are within the scope of the inventions, will be readily apparent to those of skill in the art based upon this disclosure. It is also contemplated that various combinations or subcombinations of the specific features and aspects of the embodiments may be made and still fall within one or more of the inventions. Accordingly, it should be understood that various features and aspects of the disclosed embodiments can be combine with or substituted for one another in order to form varying modes of the disclosed inventions. Thus, it is intended that the scope of the present inventions herein disclosed should not be limited by the particular disclosed embodiments described above.