Patent Publication Number: US-2022239193-A1

Title: Inverter generator

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation-in-part of U.S. patent application Ser. No. 17/336,711, filed Jun. 2, 2021, which claims the benefit of and priority to U.S. Provisional Patent Application No. 63/034,069, filed Jun. 3, 2020, both of which are hereby incorporated by reference in their entireties. 
    
    
     BACKGROUND 
     The present invention relates generally to the field of standby generators, and more particularly to the field of inverter generators. 
     SUMMARY 
     One exemplary embodiment relates to a standby generator including a standby housing defining a cavity and an internal combustion engine. The internal combustion engine includes an engine block including a cylinder comprising a piston, an engine housing at least partially covering the engine block, and a crankshaft configured to rotate about a vertical crankshaft axis in response to movement by the piston. The standby generator also includes an alternator comprising a rotor and a stator, the rotor configured to rotate with the rotation of the crankshaft to generate alternating current electrical power, a controller comprising a rectifier configured to convert the alternating current to a direct current and an inverter configured to convert the direct current to a clean alternating current electrical power, and a transfer switch configured to receive the clean alternating current electrical power from the controller and at least one of grid power from an electrical grid, solar power from a solar panel assembly, or battery power from a battery, and configured to supply power to an electrical load. The internal combustion engine, the alternator, and the controller are positioned within the cavity of the standby housing for protection from the external environment. 
     Another exemplary embodiment relates to a standby generator including a standby housing defining a cavity and an internal combustion engine. The internal combustion engine includes an engine block including a cylinder comprising a piston, an engine housing at least partially covering the engine block, a crankshaft configured to rotate about a vertical crankshaft axis in response to movement by the piston, and a spark plug configured to periodically generate a spark to ignite fuel in the cylinder to control the movement of the piston. The standby generator also includes an alternator positioned within an alternator housing and comprising a rotor and a stator, the rotor configured to rotate with the rotation of the crankshaft to generate alternating current electrical power, a controller positioned within the alternator housing and including a rectifier configured to convert the alternating current to a direct current and an inverter configured to convert the direct current to a clean alternating current electrical power, a transfer switch configured to receive the clean alternating current electrical power from the controller and at least one of grid power from an electrical grid, solar power from a solar panel assembly, or battery power from a battery, and configured to supply power to an electrical load. The controller is configured to control spark generation timing of the spark plug. The internal combustion engine, the alternator, and the controller are positioned within the cavity of the standby housing for protection from the external environment. 
     Still another exemplary embodiment relates to a standby generator including a standby housing defining a cavity and an internal combustion engine. The internal combustion engine includes an engine block including a cylinder comprising a piston, an engine housing at least partially covering the engine block, a crankshaft configured to rotate about a vertical crankshaft axis in response to movement by the piston, and a spark plug configured to periodically generate a spark to ignite fuel in the cylinder to control the movement of the piston. The standby generator also includes an alternator comprising a rotor and a stator, the rotor configured to rotate with the rotation of the crankshaft to generate alternating current electrical power, a battery configured to supply power to the alternator, and a controller including a rectifier configured to convert the alternating current to a direct current and an inverter configured to convert the direct current to a clean alternating current electrical power. The rotor is further configured to rotate the crankshaft using power from the battery to start the internal combustion engine. The internal combustion engine, the alternator, and the controller are positioned within the cavity of the standby housing for protection from the external environment. 
     This summary is illustrative only and is not intended to be in any way limiting. Other aspects, inventive features, and advantages of the devices or processes described herein will become apparent in the detailed description set forth herein, taken in conjunction with the accompanying figures, wherein like reference numerals refer to like elements. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is a rear view of a standby generator, according to an exemplary embodiment. 
         FIG. 2  is a side view of the standby generator of  FIG. 1 . 
         FIG. 3  is a top view of the standby generator of  FIG. 1 . 
         FIG. 4  is a schematic view of a twin cylinder assembly present in the standby generator of  FIG. 1 . 
         FIG. 5  is a partial exploded view of the standby generator of  FIG. 1 . 
         FIG. 6  is a perspective view of a tubular frame of the standby generator of  FIG. 1 . 
         FIG. 7  is a perspective view of a muffler of the standby generator of  FIG. 1 . 
         FIG. 8  is a perspective view of an alternator assembly of the standby generator of  FIG. 1 . 
         FIG. 9  is a perspective view of an engine housing of the standby generator of  FIG. 1 . 
         FIG. 10  is a schematic view of a controller of the standby generator of  FIG. 1 . 
         FIG. 11  is a front perspective view of a standby housing associated with the standby generator of  FIG. 1 . 
         FIG. 12  is a front perspective view of a standby housing associated with another standby generator, according to an exemplary embodiment. 
         FIG. 13  is a perspective view of the standby generator of  FIG. 12 , with the standby housing removed. 
         FIG. 14  is another perspective view of the standby generator of  FIG. 13 , detailing an inverter and other electronic components within the standby generator. 
         FIG. 15  is another perspective view of the standby generator of  FIG. 13 , detailing an airflow pattern through the standby generator. 
         FIG. 16  is another perspective view of the standby generator of  FIG. 13 , detailing an engine and alternator used by the standby generator. 
         FIG. 17  is another perspective view of the standby generator of  FIG. 13 . 
         FIG. 18  is a perspective view of the standby housing of  FIG. 12 , depicting an access door to the inverter of  FIG. 14 . 
         FIG. 19  is a perspective view of a standby generator, according to an exemplary embodiment. 
         FIG. 20  is a perspective view of an internal combustion engine and alternator assembly of the standby generator of  FIG. 19 . 
         FIG. 21  is a perspective view of an internal combustion engine and alternator assembly of the standby generator of  FIG. 19 . 
         FIG. 22  is an exploded perspective view of an internal combustion engine and alternator assembly of the standby generator of  FIG. 19 . 
         FIG. 23  is a partially exploded view of a standby generator, according to an exemplary embodiment. 
         FIG. 24  is a schematic view of the standby generator of  FIG. 19 . 
         FIG. 25  is a flow diagram of a method of operating a standby inverter generator. 
     
    
    
     DETAILED DESCRIPTION 
     Before turning to the figures, which illustrate the exemplary embodiments in detail, it should be understood that the present application is not limited to the details or methodology set forth in the description or illustrated in the figures. It should also be understood that the terminology is for the purpose of description only and should not be regarded as limiting. 
     Referring to the figures generally, a standby inverter generator is shown according to an exemplary embodiment. Inverter generators output alternating current (AC) and that current is then converted to direct current (DC), and then inverted back to clean AC power that maintains a pure sine wave at the required voltage and frequency (e.g., 120V at 60 Hz). On an inverter generator, the engine is connected to an alternator. The alternator produces AC power from the rotary motion produced by the engine and provides the AC power to a rectifier. The rectifier converts the AC power to DC power and provides the DC power to capacitors. The capacitors smoothen (e.g., filter) the DC power, which can then be inverted back into clean AC power at the desired frequency and voltage. The resultant AC power produced by the inverter generator is much cleaner power (i.e., purer sine waves) than is typical with a conventional generator. Using inverter generators, sensitive devices like microprocessors can be supplied with electricity produced by the inverter generator. Supplying devices with a relatively poor quality of electricity may damage a device or cause the device to malfunction. Accordingly, inverter generators may be useful to provide AC power in certain applications (e.g., to power medical devices, high performance computers, etc.) that traditional generators may not be suitable for. 
     The inverter generators shown and described throughout this application are also more fuel efficient than conventional generators. The inverter generators shown and described herein can adjust engine speed (e.g., drive shaft rotational speed) to meet a required electrical power load. Accordingly, when relatively low power loads are experienced, the engine speed can be reduced, which in turn lowers the fuel consumption of the generator as well as the emissions produced by the generator. Inverter generators may also reduce noise relative to conventional generators. Quieter engines, special mufflers, and sound-dampening technology may be used on inverter generators to reduce noise relative to conventional generators. In addition, conventional units generally run at a constant speed to produce electricity with the desired characteristics. Accordingly, a constant noise is produced by conventional generators. Because inverter generators can adjust the electrical characteristics of the power produced by the inverter generator, the engine within the inverter generator can throttle back when the load is light to save fuel and reduce noise caused by the unit. 
     Referring to  FIGS. 1-4 , a standby inverter generator  20  is shown according to an exemplary embodiment. The inverter generator  20  includes an internal combustion engine, shown as engine  22 , an alternator assembly  24 , a controller  26 , a muffler  28 , and a fuel connection  30 . The inverter generator  20  is positioned within and coupled to a standby housing  100 , which is configured to be positioned alongside a home or building. As depicted in  FIGS. 1-3 and 5  and explained in detail below, the inverter generator  20  is coupled to a floor panel  102  of the standby housing  100 . 
     To generate electricity, the engine  22  draws fuel through the fuel connection  30  and into an engine block  32 . Fuel is directed through the engine block  32  into one or more cylinders  34 , which house pistons  36 . Fuel is supplied into cylinder heads  38  (e.g., with an injector, like an electronic fuel injector (EFI)), mixed with air, and compressed between the cylinder head  38  and piston  36 . The gaseous fuel and air mixture is then ignited by a spark plug (not shown) that extends into the cylinder head  38 . Ignition of the fuel and air within the cylinder head  38  causes the gases within the cylinder head  38  to rapidly expand, which drives the piston  36  away from the cylinder head  38  and along a cylinder axis  40  defined by the cylinder  34  the piston  36  is received within. The coupling between the pistons  36  and a crankshaft  42  of the engine  22  causes the crankshaft  42  to rotate about its vertical crankshaft axis  44  in response to piston movement about the cylinder axes  40 . As depicted in  FIG. 4 , the engine block  32  defines two cylinders  34  that are angularly offset from one another (e.g., arranged in a V-shape) about the crankshaft axis  44 . Exhaust from the gaseous fuel and air ignition is directed outward from cylinder head  38  through the muffler  28 . 
     The rotary motion of the crankshaft  42  about the crankshaft axis  44  caused by the reciprocating pistons  36  can then be used by the alternator assembly  24  to generate electricity. The alternator assembly  24  includes a stator  46  and a rotor  48 . The rotor  48  is coupled to the crankshaft  42  so that the rotor  48  rotates in unison with the crankshaft  42 . In some examples, the rotor  48  includes magnets (e.g., permanent magnets) extending around a portion of the rotor  48  to produce magnetic fields within the alternator assembly  24 . As the rotor  48  rotates within the stator  46 , the magnetic fields created by the magnets on the rotor  48  rotate as well to produce a rotating magnetic flux. The stator  46  includes a series of coils  50  (e.g., turned copper wire) spaced about its circumference to interact with and electromagnetically oppose rotational motion of the rotor  48 . Accordingly, when the rotor  48  and associated magnets rotate within the stator  46 , the rotating magnetic flux produced by the rotor  48  will induce a current within the coils  50 . The spacing between the magnets on the rotor  48  and the coils  50  within the stator  46  and the rotary motion of the rotor  48  generates an AC electrical power output. 
     The AC electrical power output by the alternator assembly  24  is directed upwardly along one or more wires to the controller  26 . As depicted in  FIG. 10 , the controller  26  includes both a rectifier  104  and an inverter  106  to transform and condition the AC electrical power received from the alternator assembly  24 . AC electrical power is first delivered to the rectifier  104 , which transforms the AC electrical power to DC power. The DC power is then provided from the rectifier  104  to the inverter  106 . The inverter  106  inverts the DC power from the rectifier into a cleaner (e.g., higher quality) and more widely useful AC electrical power at a desired frequency and voltage (e.g., 120 VAC at 60 Hz). The generated three phase AC electrical power can then be output from the standby inverter generator  20  and used to power various electronics and building systems. The inverter  106  can be neutral bonded to a ground wire (not shown). 
     Returning to  FIGS. 1-4  and with additional reference to  FIGS. 5-9 and 11 , the structure of the standby inverter generator  20  is shown in additional detail. As explained above, the standby inverter generator  20  is coupled to the floor panel  102  of the standby housing  100 . The standby inverter generator  20  can be coupled to and supported by multiple structures that are bolted or otherwise removably coupled to the floor panel  102 . For example, an alternator stand  108  and a tubular frame  110  can be fastened to the floor panel  102  to securely but removably mount the standby inverter generator  20  to the standby housing  100 . 
     The alternator stand  108  can be a molded or bent sheet metal housing defining a mounting flange  109  and an alternator seat  111  offset from the mounting flange  109 . The mounting flange  109  defines a series of apertures that can receive one or more fasteners to mount and secure the alternator stand  108  to the floor panel  102 . In some examples, the alternator stand  108  has an open end  113  that extends upwardly away from the floor panel  102  to define a fluid flow path into and through a cavity  115  formed beneath the alternator seat  111 . With the alternator stand  108  positioned along an edge of the floor panel  102 , the open end  113  of the alternator stand  108  can serve as a cooling air intake flow path that funnels and directs air entering the standby housing  100  inward, beneath the alternator stand  108 , and into or along the outer surface of the alternator  24  to provide cooling. To maximize the cooling air intake through the open end  113  of the alternator stand  108 , the alternator stand  108  (and standby inverter generator  20 ) can be positioned so that the open end  113  faces a prevailing wind direction (e.g., the open end  113  faces westward). In some examples, a fan (not shown) is provided within the cavity  115  to further drive cooling air upward into and along the alternator assembly  24  and toward the engine  22  and inverter  106 . 
     The tubular frame  110  can include one or more sections  112  of tubing that are bent into a desired shape to suspend and support a portion of the standby inverter generator. For example, the tubular frame  110  can be formed from two symmetrical (e.g., identical) and opposing sections  112  that are positioned adjacent one another on the floor panel  102 . In some examples, an end of each section  112  of the tubular frame is designed to telescope with an opposing end of the other section  112  to create a secure yet releasable coupling between the sections  112 . 
     As depicted in  FIGS. 1-3 and 5-6 , each section  112  of the tubular frame  110  defines two legs  114  and a mounting support  116  that extends upwardly away from the legs  114 . The legs  114  extend along the floor panel  102  (e.g., coplanar with the floor panel  102 ) and define one or more apertures to receive mounting hardware (e.g., fasteners) to secure the tubular frame  110  to the floor panel  102  of the standby housing  100 . In some examples, the legs  114  of each section  112  of the tubular frame  110  extend approximately parallel to one another. The mounting support  116  of the tubular frame  110  bends upwardly away from each leg  114  to a mounting height that is vertically offset from the floor panel  102 . A support bridge  118  is formed within the mounting support  116  at the mounting height and spans the horizontal distance between the legs  114 . The support bridge  118  can extend approximately parallel to the floor panel  102 , and can be provided with a curvature to mimic or follow a curvature defining a perimeter of the alternator assembly  24 , as explained below. 
     Bosses  120  are formed along the support bridge  118  to receive and support the alternator assembly  24 . For example, four bosses  120  can be positioned about the support bridges  118  of the tubular frame  110 . The bosses  120  each support or otherwise receive a locating feature (e.g., a fastener, dowel, an aperture, etc.) to help position the alternator assembly  24  relative to the tubular frame  110 . Threaded rods  122  (e.g., set screws, molded bolts, captive screws, etc.) can be molded or anchored to the bosses  120  to serve as both locating and coupling features that can be used to secure the standby inverter generator  20  to the floor panel  102  of the standby housing  100 . In some examples, the threaded rods  122  are exposed, threaded sections of fasteners that are embedded into the bosses  120 . 
     The alternator stand  108  and the tubular frame  110  together receive and support the engine  22 , the alternator assembly  24 , the controller  26 , the muffler  28 , and the fuel connection  30 . The alternator stand  108  and tubular frame  110  are shaped to facilitate the assembly of the standby inverter generator  20  within the standby housing  100  at a desired location (e.g., a home or building where the standby inverter generator  20  will be used). As explained earlier, the alternator stand  108  is first mounted to the floor panel  102  of the standby housing  100  at a location in which the open end  113  of the alternator stand  108  engages or abuts a side panel (e.g., side panel  103 , shown in  FIG. 2 ) of the standby housing  100 . Once the alternator stand  108  has been secured to the floor panel  102 , the tubular frame  110  can be secured to the floor panel  102  as well. The legs  114  of the tubular frame  110  straddle the alternator stand  108 . The gap between the support bridges  118  of the tubular frame  110  can be approximately centered over the circular alternator seat  111  of the alternator stand  108 . 
     With the alternator stand  108  and tubular frame  110  mounted in place on the floor panel  102 , the alternator assembly  24  can be lowered into position. The alternator assembly  24  includes a generally cylindrical body  124  defined by a cylindrical housing  126  and end caps  128 ,  129 . The cylindrical housing  126  has a generally smooth interior that defines a cylindrical power generation cavity  130 . The power generation cavity  130  receives the rotor  48  and stator  46 . As depicted in  FIG. 5 , the coils  50  of the stator  46  extend circumferentially around the outside surface of the power generation cavity  130 . The rotor  48  extends into the power generation cavity  130  within a central recess  132  defined by the coils  50  that is coaxial with the crankshaft axis  44 . The external surface of the cylindrical body  124  includes a series of cooling fins  134  that extend along the body  124  approximately parallel to the crankshaft axis  44 . In some examples, the underside of the cylindrical housing  126  (e.g., the portion of the housing  126  supported on the alternator seat  111 ) and the alternator seat  111  can define one or more passages to receive and direct cooling airflow from the cavity  115  beneath alternator stand  108  upward into and around the alternator assembly  24 . The cooling airflow can rise upward, through the power generation cavity  130  and outwardly along the cooling fins  134  of the cylindrical housing  126  to direct heat upwardly away from the alternator assembly  24 . 
     The end cap  128  has an annular shape that can be secured to the cylindrical housing  126  to seal the alternator assembly  24 . The end cap  128  defines a rotor passage that is centered above the central recess  132  (e.g., aligned with the crankshaft axis  44 ) to receive a portion of the rotor  48 . In some examples, a portion of the rotor  48  extends upward, through the rotor passage and outward from the alternator assembly so that a coupling can be formed between the crankshaft  42  and the rotor  48 . The coupling formed between the crankshaft  42  and the rotor  48  allows the crankshaft  42  and rotor  48  to rotate in unison (e.g., at identical angular velocities) and transmits torque on the crankshaft  42  (e.g., from reciprocating piston  36  motion) to the rotor  48 . The rotor  48  and crankshaft  42  can extend collinear along the crankshaft axis  44 . 
     Mounting wings  136  extend outwardly from a top of the end cap  128  to help locate and secure the cylindrical housing  126  of the alternator assembly  24  to the tubular frame  110 . The mounting wings  136  can be equally spaced about a perimeter of the end cap  128  (e.g., positioned about 90 degrees apart from one another) to help promote a secure coupling between the end cap  128  and the tubular frame  110 . The mounting wings  136  each define a shelf  138  that extends away from a top of the end cap  128 . In some examples, the shelf  138  extends approximately parallel to the floor panel  102  below. The shelves  138  each define a hole  140  that can be used to locate the end cap  128  and alternator assembly  24 , more generally, with the tubular frame  110 . To facilitate coupling between the alternator assembly  24  and the tubular frame  110 , the holes  140  within the shelves  138  can be aligned with the threaded rods  122  protruding upwardly from the bosses  120  formed on the support bridges  118  of the tubular frame  110 . As the end cap  128  is lowered toward the floor panel  102 , the threaded rods  122  extend through the holes  140  and upwardly beyond each shelf  138 . While an underside of the shelf  138  can be seated on the boss  120 , the exposed portion of the threaded rod  122  can receive a fastener  142  (e.g., a nut and lock washer) that can be torqued to secure the end cap  128  to the tubular frame  102  to mount the alternator assembly  24  into place within the standby housing  100 . In some examples, the shelves  138  further support engine locating features, shown as dowels  144 , to help complete the assembly of the standby inverter generator  20 . 
     As depicted in  FIGS. 1-3, 5, and 7 , the shelves  138  and threaded rods  122  (e.g., shanks of imbedded screws) from the bosses  120  can also be used to mount and secure the muffler  28  to the tubular frame  110  and the standby inverter generator  20 . A bracket  146  is mounted to a top side of the muffler  28  to mount the muffler  28  in a location spaced apart from other heat generating or heat sensitive components (e.g., the engine  22  and the alternator assembly  24 ). Accordingly, the bracket  146  can serve as a heat shield to prevent the transfer of heat within the muffler  28  to the engine  22  that may otherwise cause damage to wear parts within the engine  22  (e.g., engine crankshaft oil seals, etc.). The bracket  146  also provides a pathway for cooling air to approach the muffler  28  from multiple directions simultaneously. The bracket  146  is defined by an H-shape that includes two mounting tabs  148  coupled to a top of the muffler  28 . Legs  150  extend upwardly and perpendicularly away from the mounting tabs  148 . Arms  152  then extend outwardly and perpendicularly away from the legs  150 . The spacing between the arms  152  can be variable (e.g., the spacing changes as the arms  152  extend away from the legs  150 ). As depicted in  FIG. 7 , the arms  152  taper outwardly away from one another to achieve a spacing that is approximately equal to the spacing between the bosses  120  on the tubular frame  110 . Holes  154  are formed through distal portions of the arms  152  to receive the threaded rods  122 . Accordingly, two of the threaded rods  122  and nuts may be used to support and secure both the bracket  146  and the mounting wings  136  of the end cap  128  to the tubular frame  110  simultaneously. 
     The muffler  28  includes a generally cylindrical body  156  that defines a muffler chamber  158 . The generally cylindrical body  156  extends along a muffler axis  157  that is approximately (e.g., within 5 degrees) perpendicular to the crankshaft axis  44 . Conduits  160  (e.g., hoses, pipes, tubes) extend away from the muffler chamber  158  to fluidly couple the muffler  28  with the cylinder heads  38  of the engine  22 . Exhaust gases from combustion within the cylinders  34  are pushed by the piston  36  outward from the cylinder head  38 , through the conduits  160 , and into the muffler chamber  158 . Within the muffler chamber  158 , the exhaust gases are passed through a series of baffles or other sound muffling devices (e.g., tubes, resonating chambers, etc.) that help dampen and dissipate noise generated by the engine  22 . After passing through the muffler chamber  158 , the exhaust gases are directed outward from the standby inverter generator  20  through an exhaust pipe  162  extending outwardly away from the cylindrical body  156 , and into the external environment (or within the standby housing  100 ). In some examples, an exhaust port  163  (shown in  FIG. 11 ) is formed within one of the side panels  103  of the standby housing  100  to release the exhaust gases from the exhaust pipe  162  outward from the standby housing  100  to alleviate heat within the standby housing  100 . 
     Referring now to  FIGS. 1-5 and 9 , the engine  22  is shown. The engine  22  generally includes an engine housing or blower housing  164  that defines an engine cavity  166 . The engine block  32  of the engine  22  is at least partially received within the engine cavity  166  and is at least partially covered by the engine housing  164 . The engine housing  164  can further define a battery box  168 . The battery box  168  can be positioned between the cylinders  34  within the engine block  32 , and can be used to house an on-board battery (e.g., battery  169 , shown in  FIG. 10 ). The on-board battery can be an absorbent glass mat (AGM) battery, for example, which supplies electrical power to the spark plugs to ignite the fuel and air mixture within the cylinders  34  to start the engine  22 . In some instances, the battery can also be used as a booster to help supply electricity when a spike in generator load is requested. The battery can supply DC electrical power to the inverter  106 , which can then be inverted to AC power and output for use. The battery box  168  can be positioned between the cylinders  34  and proximate the cylinder heads  38 , which simplifies the electrical flow path between the battery and the spark plugs within the cylinder heads  38 . Various other electronics can be positioned within the battery box  168  as well. 
     With additional reference to  FIG. 11 , the standby housing  100  is shown in additional detail. As explained above, the standby housing  100  generally includes a floor panel  102 , side panels  103  extending upwardly away from the floor panel  102 , and a cover  105  that together define a cavity. The floor panel  102 , side panels  103 , and cover  105  together surround the standby inverter generator  20  to protect the standby inverter generator  20  from the external environment (e.g., dust, rain, wind, etc.) In some examples, one or more of the side panels  103  define cooling air intakes to help direct cooling air from the external environment into cavity and along the various components of the standby inverter generator  20 . As depicted in  FIG. 11 , the side panel  103  can include separate air intakes  172 ,  174  for the alternator assembly  24  and the engine  22 . The air intakes  172 ,  174  can be spaced apart from one another vertically along the side panel  103 . In some examples, the air intakes  172 ,  174  perform an air filtration function as well. The air intakes  172 ,  174  can be provided with filters or can be defined by one or more louvered panels to restrict the inward flow of contaminants through the side panel  103  and into contact with the standby inverter generator  20 . In some examples, the floor panel  102  is fortified by one or more pieces of bar stock (not shown) that help maintain rigidity within the floor panel  102 , particularly during travel. 
     The controller  26  and inverter  106  are coupled to the engine housing  164 . As depicted in  FIGS. 3, 5, and 9-10 , the controller  26  and inverter  106  are positioned above the engine block  32  and above the engine  22 , generally. By placing the inverter  106  and controller  26  above the engine  22 , the cooling airflow around these components can be maximized. Cooling air entering through the top of the standby housing  100  (e.g., within holes within the side panels  103  or beneath the cover  105 ) will be directed over and past the inverter  106  and controller  26  to remove heat generated by these components. Simultaneously, the cooling air entering from the bottom of the standby housing  100  will be directed upward as it heats up, and will once again pass over the inverter  106  and controller  26  as it rises and exits the standby housing  100 . In some examples, the inverter  106 , alternator assembly  24 , and engine  22  all have separate air intakes. In some examples, once cooling air has passed over the inverter  106  and/or engine  22  and alternator assembly  24 , the warmer air can exit through the air intakes  172 ,  174  formed in the side panel  103 . As depicted in  FIG. 3 , two of the side panels  103  can serve as cooling air inlets, while the remaining side panels  103  (e.g., the side panel  103  that includes the exhaust port  163 ) can serve as cooling air outlets. 
     The controller  26  is in communication, generally, with the engine  22  and fuel delivery systems (e.g., fuel injectors receiving fuel from a fuel tank coupled to the fuel connection  30 ), as well as with various external sources. The controller can interact with and adjust a rate of fuel supply to the internal combustion engine  22  to adjust the speed of the internal combustion engine  22 . In some examples, the controller  26  can be supplied with power from the battery within the battery box  168 , so that the controller  26  remains active regardless of the current operational status of the engine  22 . The controller  26  can also be provided with a control wire or signal in communication with an associated building power line, which can allow the controller  26  to actively monitor the power consumption within the building that the standby inverter generator  20  is associated with. If the controller  26  detects a surge or interruption in the power supply within the building, the controller  26  can initiate an ignition sequence for the engine  22  to begin operating. 
     The controller  26  is configured to operate the standby inverter generator  20  in various different modes to improve efficiency and decrease fuel consumption, noise, and emissions relative to conventional standby generators. Because the controller  26  is in communication with the control wire or signal from the building, the controller  26  can monitor the requested or required load to power devices within the building. Accordingly, the controller  26  optimizes the operation of the engine  22  so that only the necessary amount of power is outputted by the inverter generator  20  at a given time. By adjusting the engine speed and output, the controller  26  can operate the engine  22  so that the amount of AC electrical power generated by the standby inverter generator  20  is correlated to the requested load. In some examples, the controller  26  controls the standby inverter generator  20  to output an amount of AC electrical power that is greater than the current requested load by a threshold amount (e.g., 10% or 20% more) to accommodate additional power requests that may occur within the building instantaneously. The engine  22  is not governed at a specific angular velocity, which allows the standby inverter generator  20  to avoid waste and eliminates unnecessary fuel consumption and noise production. 
     The controller&#39;s  26  ability to adjust engine speed and output enables the use of different operational modes that further improve the efficiency of the standby inverter generator  20  while lowering the fuel consumption, emissions, and noise production. Under normal loading conditions, the controller  26  controls the engine  22  so that the pistons  36  within the cylinders  34  alternate and reciprocate to drive the crankshaft  42 . The engine speed can be adjusted upward or downward by adjusting the rate of fuel delivery into the cylinders  34  in order to meet power load demands. In some examples, the controller  26  can be configured to operate the engine  22  to accommodate very low power load demands. When the requested power load is below a certain threshold value (e.g., less than 30% of maximum output of the standby inverter generator  20 , etc.) the controller  26  may control the engine  22  so that only one of the two cylinders  34  operates. Accordingly, fuel will only be delivered to one of the two cylinders  34 , and battery power will only be supplied to the spark plug positioned in one of the two cylinder heads  38 . With only one of two cylinders  34  operating, the torque and rotational speed of the crankshaft and, as a result, the rotor  48  will be reduced. However, the controller  26  can maintain the engine speed such that even with a single cylinder  34  firing, the rotor  48  generates AC electrical power that can be supplied to the rectifier  104  and inverter  106  and outputted at the desired frequency and voltage. Accordingly, the controller  26  can control the engine to operate at much lower speeds (e.g., 1400 rpm) than conventional generators to still output the necessary amount of AC electrical power. 
     The selective operation of the cylinders  34  can also be used by the standby inverter generator  20  to execute “exercise mode” operations to maintain the readiness of the standby inverter generator  20 . Periodically (e.g., once a week, once a month, once a quarter, etc.) the controller  26  can transition the standby inverter generator  20  to exercise mode in order perform routine exercise procedures. In the exercise mode, the controller  26  once again controls the engine  22  so that only a single cylinder  34  is operating. Alternatively, the engine  22  can be operated at a much lower frequency (e.g., 1400 RPM, 1800 RPM, etc.) using both cylinders  34 . The lower output of the engine  22  and reduced angular velocity of the crankshaft  42  and rotor  48  can cycle fuel through the fuel system of the standby inverter generator  20  and generate an amount of electrical power that is below a rated capacity of the standby inverter generator  20 . The electrical power generated by the standby inverter generator  20  in the exercise mode can be sufficient to partially or fully recharge the battery within the engine housing  164 . Accordingly, the electrical power generated by the alternator assembly  24  can be provided to the rectifier  104  and diverted to the battery, rather than output through the inverter  106 . 
     The controller  26  can activate or transition the standby inverter generator  20  to the exercise mode in a variety of ways. For example, the controller  26  may monitor the crankshaft  42 . If a threshold time period has elapsed (e.g., one week, one month, 90 days, etc.) where the crankshaft  42  has remained idle, the controller  26  can initiate the exercise mode. The controller  26  can activate an ignition sequence by drawing electricity from the battery to power the fuel delivery system and spark plugs within one of the two cylinders  34 . Once combustion has occurred within the cylinder  34  and the crankshaft  42  begins rotating, the power to operate the fuel delivery system and spark plugs can be diverted from the rectifier  104  to continue operation of the standby inverter generator  20 . The controller  26  can continue to operate the engine  22  in the exercise mode until a threshold time period (e.g., fifteen minutes, one hour, etc.) has elapsed. Upon receiving an indication that the threshold time period has elapsed, the controller  26  can command the internal combustion engine  22  to cease operating. In some examples, the controller  26  disconnects the fuel delivery system and spark plugs from an electrical power supply to effectively shut down the engine  22 . 
     The controller  26  can also be configured to output AC electrical power at different frequencies to accommodate different electrical power needs. By controlling the engine speed, the controller  26  effectively controls the angular velocity of the rotor  48 . The relationship between the rotor  48  and stator  46  is such that varying the angular velocity of the rotor  48  can change the characteristics of the signal being output by the alternator assembly  24 . In some examples, the inverter  106  is further configured to accept the DC electrical power from the rectifier  104  and invert the DC electrical power to clean 50 Hz AC electrical power. The inverter  106  can communicate with the controller  26  to adjust engine speed to accommodate a desired output characteristic of the electrical power from the standby inverter generator  20 . The standby inverter generator  20  does not experience any derating due to the engine speed changes. Accordingly, the standby inverter generator  20  can be used in various locations and may be cross-compatible in both the United States and throughout several countries of the world. 
     The controller  26  can also be provided with preset operational parameters that can be selected by a user. For example, the engine  22  of the standby inverter generator  20  can be compatible with several fuel types (e.g., natural gas, propane, gasoline, etc.). Because the fuel sources have different relative energy densities, the rate of fuel delivery may differ across fuel types. In order to achieve the same (or similar) AC electrical power output from the standby inverter generator  20 , the controller  26  (or an actuator or display) may prompt a user to select a fuel source type. The selection can be made by moving or actuating a button or otherwise making a selection via a display that is in communication with the controller  26 . Upon receiving a selection, the controller  26  can access a memory  170  (e.g., an on-board memory or cloud-based memory), which stores operational parameters associated with the selected fuel source. The controller  26  can then communicate with the fuel delivery system and spark plugs of the engine  22  to provide fuel and perform combustion at a frequency necessary to drive the crankshaft  42  and rotor  48  at an angular velocity sufficient to generate the desired electrical load. 
     Although shown as a singular unit, the standby inverter generator  20  can be included in series or in parallel with additional standby inverter generators  20  to increase the total power generation capacity for a building. For example, two 6.5 kW rated standby inverter generators can be positioned in parallel to increase the power delivery capability of the standby inverter generators  20 . Each standby inverter generator  20  can be provided with its own controller  26  or, alternatively, a single controller  26  can control both units. In some examples, one standby inverter generator  20  includes a master controller  26  that can communicate with a slave controller on the one or more additional standby inverter units coupled together. In some examples, the standby inverter generator  20  is a 9.5 kW unit. 
     Referring now to  FIGS. 12-18 , another standby inverter generator  220  is depicted. The standby inverter generator  220 , like the standby inverter generator  20 , includes an internal combustion engine  22 , an alternator assembly  24 , a controller  26 , and a muffler  28 . The inverter generator  220  is positioned within and coupled to a standby housing  300 , which is configured to be positioned alongside a home or building. As depicted in  FIGS. 13-17 , the inverter generator  220  is coupled to a floor panel  302  of the standby housing  300 . A fuel connection  30  can be positioned near a perimeter of the floor panel  302 , and can extend through the standby housing  300  to form a coupling with a fuel source, like compressed natural gas, propane, gasoline, or other suitable energy source. As depicted in  FIG. 14 , the fuel connection  30  can include a flow regulator to help meter the flow of fuel from a nearby fuel source (not shown) into the internal combustion engine  22 . The controller  26  (which includes the inverter  106 ) extends at least partially above the internal combustion engine  22  and alternator assembly  24 , and approximately parallel to an outer surface of the standby housing  300 . 
     The standby inverter generator  220  has a compact design that reduces the overall footprint of the system relative to conventional generators. For example, and as depicted in FIG.  16 , the alternator assembly  24  is defined by a height that is less than half a height defining the engine block  32 . By reducing the height of the alternator assembly  24 , the internal combustion engine  22  can be positioned lower to the floor panel  302 , which can further promote cooling. 
     The standby inverter generator  220  and its associated standby housing  300  are designed to improve airflow and cooling of the various heat-generating components within the standby inverter generator  220 . As depicted in  FIGS. 13-17 , the alternator assembly  24  and internal combustion engine  22  are each suspended off of the floor panel  302  to allow airflow beneath the components. Like the inverter generator  20 , the inverter generator  220  also includes an alternator stand  108  that is configured to permit airflow beneath the alternator assembly  24 . The internal combustion engine  22  is suspended away from the floor panel  302  by a frame, shown as support structure  280 , that is formed of a combination of support bars  282  and one or more panels  284 . The support bars  282  can be bent, welded, or otherwise formed into a shape that provides a support surface  286  that extends approximately parallel to the floor panel  302 . The support surface  286  can include one or more bosses  288  that are used to mount the engine block  32  to the floor panel  302 . In some examples, the one or more panels  284  can be formed to extend around the engine block  32  to serve as a heat shield between the muffler  28  and the internal combustion engine  22  and alternator assembly  24 . 
     The standby inverter generator  220  is designed to direct cooling air into and through the different heat generating components. As depicted in  FIG. 18 , the standby housing  300  is formed of panels  304  and a roof  306 . The panels  304  extend away from the floor panel  302  and can support a series of vents, shown as grilles  308  that allow air to enter into the standby housing  300 . In some examples, the grilles  308  include one or more louvered panels that are designed to filter out contaminants from cooling air prior to entering into the standby housing  300 . 
     The primary air flow pattern through the standby housing  300  directs cooling air over the controller  26  and inverter  106  first, to the electrical panel  290 , and then down into and toward the internal combustion engine  22  and out of the standby housing  300 . As depicted in  FIG. 14 , air is first directed through a grille  308  formed in a panel  304  toward the controller  26  and inverter  106 . The high electrical loading of these components generates a significant amount of heat that is advantageously removed from the system. By directing the primary airflow through the standby housing  300  toward the inverter  106  and controller  26  first, ambient air will contact the inverter  106  and controller  26  when the air is at its coolest temperature. Accordingly, air having the greatest capacity for cooling the system will be directed over the most heat-sensitive components first. 
     The cooling air passes toward the inverter  106  and controller  26  and is heated as the air passes over these components. As the air warms and carries heat away from the inverter  106  and controller  26 , the air rises within the standby housing  300 . A passage is formed above the inverter  106  and controller  26  that directs this air toward the electrical panel  290  that extends above the internal combustion engine  22  and alternator assembly  24 . As depicted in  FIG. 15 , the electrical panel  290  is suspended above the internal combustion engine  22  and separated from the internal combustion engine  22  by an air gap  292 . The air gap  292  can be defined by a tray  294  that receives the electrical panel  290  and a heat shield  296  extending above the internal combustion engine  22 . The tray  294  and the heat shield  296  can extend approximately parallel to one another and approximately parallel to the floor panel  302 . 
     The heated air passes over electrical panel  290 , toward a recess  298  formed within the tray  294  and through the heat shield  296 , as depicted in  FIG. 15 . The heated air then travels downward, through the tray  294  and the heat shield  296 , and to the internal combustion engine  22 . The operation of the internal combustion engine  22  can create a low pressure area near the internal combustion engine  22  which urges the air downward. In some examples, a portion of the cooling air can be used by the internal combustion engine  22  to execute the combustion reaction to drive the engine  22 . The remaining cooling air can pass along the exterior of the engine block  32  and the alternator assembly  24  to carry heat away from these components. Additional grilles  308  can be formed within the panels  304  to direct the cooling air outward from the standby housing  300 , and back to the external environment. Using the primary cooling path, the most heat-sensitive heat generating components can be provided with external cooling air first, which can help to promote a more effective cooling process. 
     Referring now to  FIG. 18 , the standby housing  300  is configured to provide easy access to the various electrical components of the standby inverter generator  220 . In some examples, the roof  306  is designed to be removable from the rest of the enclosure. In addition to the roof  306  being removable, one or more of the panels  304  can be designed to provide access into the inverter  106  and/or controller  26 . For example, the panel  310  extending in front of the inverter  106  and controller  26  can be rotatably coupled to the rest of the standby housing  300 . The panel  310  can be supported by hinge joints  312  that allow the panel  310  to rotate relative to the roof  306  or relative to the other panels  304 , to a position that permits access to the inverter  106  and controller  26  positioned nearby. 
     Using the aforementioned controller  26 , the engine  22  can be controlled to accommodate varying electrical power loads in a manner that avoids excess fuel consumption or unused power. By controlling the engine speed to mirror (or slightly overshoot) the required power output, the engine can run at lower speeds when appropriate, which reduces the amount of noise and fuel emissions outputted by the standby inverter generator. By further controlling the engine to fire only one of two cylinders  34  in certain situations, the emissions and noise can be further limited. Significant efficiency gains result from the low power exercise mode carried out by the controller  26  and engine  22 . The engine  22  and controller  26  also enable the standby inverter generator to operate on multiple different fuel sources effectively. 
     Various other advantages are achieved by the standby inverter generator  20  disclosed. The alternator assembly  24  has a high frequency output, which allows the overall standby inverter generator to be shorter (e.g., by about 6 inches). The height reduction in turn allows the inverter  106  and associated controller  26  to be positioned above the engine  22 , in a position where it is easier to access and more directly within the flow path of cooling air from multiple directions. The inverter  106  can provide clean AC electrical power at different frequencies to accommodate different loading. Similarly, the vertical orientation of the crankshaft  42  reduces the horizontal footprint of the standby inverter generator  20 , allowing for smaller standby housings  100  to be used. In some examples, the floor panel  102  is reinforced to allow the standby housing  100  and standby inverter generator  20  to be moved using a standard dolly. 
     Referring now to  FIGS. 19-22 and 23 , another exemplary embodiment of a standby inverter generator  420  is depicted. The standby inverter generator  420  may be substantially similar to the standby inverter generator  2  except as described herein. For example, the standby inverter generator  420  includes an internal combustion engine  422 , an alternator assembly  424 , a controller  426 , an intake manifold  430 , and a muffler  428 . In some embodiments, the controller  426  may be within the alternator housing  423  of the alternator assembly  424  and not visible. The inverter generator  420  is positioned within and coupled to a standby housing  500 , which is configured to be positioned alongside a home or building. The inverter generator  420  sits on a frame  510  that is coupled to a floor panel  502  of the standby housing  500 . The frame  510  is configured to couple the internal combustion engine  422  to the floor panel  502  and to separate each of the other components of the standby inverter generator  420 . The side walls and upper panel of the standby housing  500  are not shown. A fuel connection can be positioned near a perimeter of the floor panel  502 , and can extend through the standby housing  500  to form a coupling with a fuel source, like compressed natural gas, propane, gasoline, or other suitable energy source. In other embodiments, the fuel connection can be positioned in other locations. 
       FIGS. 20 and 21  are perspective views of the internal combustion engine  422  and the alternator assembly  424  of the standby inverter generator  420  in different orientations.  FIG. 22  shows an exploded perspective view of the internal combustion engine  422  and alternator assembly  424  in the orientation shown in  FIG. 21 . The alternator housing  423  is not shown in  FIGS. 20, 21, and 22 . The alternator assembly  424  of the standby inverter generator  420  is positioned above and is coupled to the internal combustion engine  422 . Referring now to  FIG. 22 , the alternator assembly  424  includes a stator  446  and a rotor  448 . The crankshaft  442  of the internal combustion engine  422  extends through the stator  446  and is coupled to the rotor. As described above, the rotor  448  rotates with the crankshaft  442  and the rotating rotor magnets generate a magnetic flux that induces an electrical current in the coils  450  of the stator  446 , generating alternating current electrical power. The alternating current electrical power is directed to the controller  426 , which includes a rectifier  504  and an inverter  506 , for selectively converting the alternating current electrical power into direct current electrical power and back to stable alternating current electrical power. 
     The alternator assembly  424  includes a fan  451  positioned above and coupled to the rotor  448 , e.g., via a plurality of fasteners  453 . The fan  451  pulls in air from above the standby inverter generator  420  and pushes it down through the alternator assembly  424  to an air intake of the internal combustion engine  422 . The rotor  448  may include a plurality of openings  455  configured to allow air to pass through the rotor  448  to the internal combustion engine  422 . At least a portion of the air is used in the combustion of fuel in the cylinders  434  internal combustion engine  422 . The air moved through the alternator assembly  424  by the fan  451  also acts to cool the alternator assembly  424  and the internal combustion engine  422  without the need for additional fans, blowers, or ducting. Exhaust from the cylinders  434  is directed to the muffler  428 , which reduces the sound generated by the internal combustion engine  422 . The muffler  428  is positioned below the internal combustion engine  422 . Air flow generated by the fan  451  may also cool the muffler  428 . 
     In some embodiments, the alternator assembly  424  may be operated as a starter motor to provide the initial rotation of the crankshaft  442  required to start the engine  422 . The coils  450  in the stator  446  of the alternator assembly  424  draw power from a battery (not shown), generating an electromagnetic field. The electromagnetic field causes the rotor  448  of the alternator assembly  424  to rotate. Thus, the alternator assembly  424  essentially operates in reverse to generate rotation of the rotor  448  using electricity, rather than generating electricity from the rotation of the rotor  448  by the internal combustion engine  422 . Because the rotor  448  is coupled to the crankshaft  442 , the crankshaft  442  rotates with the rotor  448 , which causes the pistons of the cylinders  434  to reciprocate. The internal combustion engine  422  can then begin operate as described above, by igniting an air and fuel mixture in the cylinders  434  using spark plugs to fire the pistons and rotate the crankshaft  442 . The alternator assembly  424  can then stop operating as a starter motor and begin to operate as an alternator to generate electricity from the rotation of the crankshaft  442  by the engine  422  following a set period of time, in response to threshold engine speed, and/or in response to another indication the engine  422  has been started. 
     The controller  426  (shown in  FIG. 19 ) can be configured to control the rotational speed of the rotor  448  when starting the engine  422 . As discussed above with reference to the generator  20 , during operation of the generator  420 , the controller  426  can be configured to control the speed of the engine  422  to match the required power demand (e.g., the electrical load) on the generator  420 . The controller  426  can similarly be configured to control the starting speed of the rotor  448  and thus the crankshaft  442  during startup so that the engine speed can immediately match the power demand when the generator  420  starts. This allows for a more seamless transition from grid power to generator power and can reduce noise at startup compared to using startup speed set to a maximum speed. As described above with respect to the controller  26 , the controller  426  also comprises a rectifier  504  and an inverter  506  respectively configured to convert the AC power from the generator  20  to DC power, and back to a cleaner (e.g., higher quality) and more widely useful AC electrical power at a desired frequency and voltage (e.g., 120 VAC at 60 Hz). 
     The controller  426  can also be configured to control the spark generation timing of the spark plug (not shown). For example, the controller  426  can be configured to delay the spark plug timing at slower speeds such that the cylinders  434  fire near top dead center. At higher speeds, the controller  426  can be configured to fire earlier than when the cylinders  434  are at top dead center. This allows for more efficient use of fuel and operation of the engine  422 . The controller  426  can be electrically coupled to the spark plugs and can send electricity to the spark plug to generate a spark. Because the rotor  448  is coupled to the crankshaft  442 , the position of the rotor  448  can be used to determine the position of the pistons. For example, the alternator assembly  424  may include a rotor position sensor that is communicatively coupled to the controller  426  and configured to detect the position of the rotor  448 . The controller  426  may receive rotor position data from the rotor position sensor and may use the rotor position data to determine when to fire the spark plugs. When starting the internal combustion engine  422 , the controller  426  may control the spark generation timing of the spark plug based on the starting speed determined as described above. 
     The spark plug firing timing can also be adjusted based on fuel type. For example, the generator  420  may be configured to run on both liquefied petroleum (LP) and natural gas (NG). Because these fuels may burn and expand at different rates, the timing of spark plug firings needs to be adjusted to ensure efficient operation of the engine  422 . As shown in  FIG. 19 , the generator  420  may include a switch  465  (e.g., rocker switch, knob, button, etc.) that allows a user to input whether the fuel used is LP, NG or some other fuel (e.g., gasoline).  FIG. 24  is a schematic view of the standby inverter generator  420 , including the switch  465 . The controller  426  may receive a signal from the switch  465  and may adjust the timing of the spark plug firings based on the signal received. In some embodiments, the switch  465  may also enable the flow of one type of fuel while disabling the flow of another type of fuel. For example, moving the switch  465  to the NG position may open a first valve that allows NG from an NG supply to flow into the cylinders  434  and may close a second valve, stopping LP from flowing into the cylinders  434 . Moving the switch  465  may physically open and close the valves or may send an electrical signal causing the valves to open and close. The switch  465  may be positioned on the alternator housing  423 , on a fuel line remote from the generator  420 , or elsewhere in the generator  420 . As discussed above, moving the switch  465  may act to both determine the fuel type allowed to reach the cylinders  434  and send an indication of the selected fuel type to the controller  426 . Fuel flow into the cylinders  434  may be governed by a regulator and/or an electronic fuel injector. As described above, the alternator  424  generates AC power  425 , which is directed the rectifier  504  within controller  426 . The rectifier  504  generates DC power  427 . The DC power  427  is directed to the inverter, which converts the DC power from the rectifier  504  to stable AC power  429  suitable for use in a home or other building. Some of the DC power  427  may be directed to a battery  569  for later use. 
     In some embodiments, the generator  420  may include a sensor configured to detect the type of fuel being delivered to the engine  422 . For example, the sensor may be a chemical sensor configured to detect levels of certain components of the fuel. The controller  426  may be communicatively coupled to the sensor and configured to receive a signal from the sensor indicating the fuel type. The controller  426  can adjust the timing of the spark plug firings based on the signal received from the sensor. In other embodiments, the fuel type may be input via a digital user control panel. 
     Referring still to  FIG. 24 , in some embodiments, the inverter  506  delivers the stable AC power  429  to a transfer switch  2402 . The transfer switch  2402  may also be configured to receive power from the electrical grid  2404 , a solar panel system  2406 , and a battery  2408 . The transfer switch  2402  is configured to switch between the various power sources to supply power to the building  2410 . For example, if grid power  2404  fails (e.g., during a blackout) and no power is available from the solar panels  2406  (e.g., at night), the transfer switch may supply power form the battery  2408  and/or the standby inverter generator  420  to the building  2410 . In some embodiments, the transfer switch  2402  may be configured to allow the standby inverter generator  422 , the grid power  2404 , and/or the solar panels  2406  to charge the battery  2408 . In some embodiments, the transfer switch  2402  may be referred to as a component of the inverter generator  422 . In some embodiments, the transfer switch  2402  is configured to be attached to a building  2410  and is attached to the building  2410  when the standby inverter generator  420  is installed on site. For example, the transfer switch  2402  may be attached to a wall of the building  2410  near the building&#39;s circuit breaker panel. 
       FIG. 25  illustrates a method  2500  of controlling a standby inverter generator (e.g., standby inverter generator  420 ). The method may be performed, for example, by controller  426 . At operation  2502  of method  2500 , an indication of a power demand form a load source is received. For example, the controller  426  may receive an indication of a power demand from a building. The indication may also signal the controller  426  to start the internal combustion engine  422 . At operation  2504  of method  2500 , an indication of a fuel type is received. For example, the controller  426  may receive an indication of a fuel type from the switch  465  or from a fuel type sensor. At operation  2506  of method  2500 , a starting speed of the engine is determined based on the power demand. For example, the controller  426  may control the starting speed of the engine  422  such that the standby inverter generator  420  produces the appropriate amount of power to meet the power demand of the building. At operation  2508  of method  2500 , spark plug timing for the engine is determined based on the fuel type. For example, as described above, the controller  426  may determine the spark plug timing based on whether the fuel source is LP, NG, or gasoline. At operation  2510  of method  2500 , the motor is started using the determined engine starting speed and spark plug timing. For example, the controller  426  may start the internal combustion engine  422  using the determined starting speed and spark plug timing. Once started, the engine  422  can continue to run using the determined starting speed and spark plug timing. At operation  2512  of method  2500 , the engine speed is adjusted based on changed to the power demand. For example, when the load on the building increases or decreases, the controller  426  can adjust the engine speed to such that the standby inverter generator  420  produces the appropriate amount of power to meet the new power demand. 
     Referring now to  FIG. 23 , another exemplary embodiment of a standby inverter generator  620  is depicted. The standby inverter generator  620  includes an internal combustion engine  622 . The internal combustion engine  622  is a single cylinder, horizontal shaft engine. In other embodiments of a standby inverter generator, the internal combustion engine may be a multiple cylinder horizontal shaft engine, for example, a v-twin horizontal shaft engine. In still other embodiments of a standby inverter generator, the internal combustion engine may be a single cylinder vertical shaft engine. The internal combustion engine includes a single cylinder  634  and a crankshaft  642 . The standby inverter generator  620  is positioned within and coupled to a standby housing  700 , which is configured to be positioned alongside a home or building. The standby inverter generator  620  sits on a frame  710  that is coupled to a floor panel  702  of the standby housing  700 . The frame is configured to couple the internal combustion engine  622  to the floor panel  702  and to separate each of the other components of the standby inverter generator  620 . The side walls and upper panel of the standby housing  700  are not shown. However, the standby housing  700  may be substantially similar to the standby housing  100  shown in  FIGS. 11 and 12 . A fuel connection can be positioned near a perimeter of the floor panel  702 , and can extend through the standby housing  700  to form a coupling with a fuel source, like compressed natural gas, propane, gasoline, or other suitable energy source. A muffler  628  is coupled to the frame  710  under the internal combustion engine  622 . In other embodiments, the muffler  628  may be positioned next to the internal combustion engine  622 , e.g., on the opposite side of the crankshaft  642 . The standby housing  700  is similar to and can include the same components as the standby housings  100  and  300 . 
     Like the standby inverter generator  420 , the standby inverter generator  620  includes an alternator assembly  624 , including a stator  646  and a rotor  648 . The crankshaft  642  of the internal combustion engine  622  extends through the stator  646  and is coupled to the rotor  648 . As described above, the rotor  648  rotates with the crankshaft  642  and the rotating rotor magnets generate a magnetic flux that induces an electrical current in the coils  650  of the stator  646 , generating alternating current electrical power. The standby inverter generator  620  includes a controller  626  configured to control the standby inverter generator similarly to the controller  626  of standby inverter generator  420 . For example, the controller  626  includes a rectifier  704  and an inverter  706  to convert the alternating current output by the alternator assembly  624  to a clean alternating current. The controller  626  is also configured to control spark plug timing, control the speed of the engine  622  in response to a detected electrical load, and to control the rotor  648  speed when the alternator assembly  624  is used to start the engine, as discussed above with respect to controller  26  and controller  426 . 
     The alternator assembly  624  also includes a fan  651  coupled to the rotor  648 . The fan  651  is configured to pull in air from next to the standby inverter generator and push the air through the alternator assembly  624  to the internal combustion engine  622 . The engine  622  may draw in a portion of the air to be used in the combustion of fuel in the cylinder  634  internal combustion engine  622 . The airflow from the fan  651  may also cool the alternator assembly  624 , engine  622 , and muffler  628 . 
     Although this description may discuss a specific order of method steps, the order of the steps may differ from what is outlined. Also, two or more steps may be performed concurrently or with partial concurrence or certain method steps may not be performed. Such variation will depend on the software and hardware systems chosen and on designer choice. All such variations are within the scope of the disclosure. Likewise, software implementations could be accomplished with standard programming techniques with rule-based logic and other logic to accomplish the various connection steps, processing steps, comparison steps, and decision steps. 
     As utilized herein, the terms “approximately”, “about”, “substantially”, and similar terms are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. It should be understood by those of skill in the art who review this disclosure that these terms are intended to allow a description of certain features described and claimed without restricting the scope of these features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of the invention as recited in the appended claims. 
     It should be noted that the term “exemplary” as used herein to describe various embodiments is intended to indicate that such embodiments are possible examples, representations, and/or illustrations of possible embodiments (and such term is not intended to connote that such embodiments are necessarily extraordinary or superlative examples). 
     The terms “coupled,” “connected,” and the like, as used herein, mean the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g., permanent, etc.) or moveable (e.g., removable, releasable, etc.). Such joining may be achieved with the two members or the two members and any additional intermediate members being integrally formed as a single unitary body with one another or with the two members or the two members and any additional intermediate members being attached to one another. 
     References herein to the positions of elements (e.g., “top,” “bottom,” “above,” “below,” “between,” etc.) are merely used to describe the orientation of various elements in the figures. It should be noted that the orientation of various elements may differ according to other exemplary embodiments, and that such variations are intended to be encompassed by the present disclosure. 
     The construction and arrangement of the standby inverter generator as shown in the exemplary embodiments is illustrative only. Although only a few embodiments of the present disclosure have been described in detail, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited. For example, elements shown as integrally formed may be constructed of multiple parts or elements. It should be noted that the elements and/or assemblies of the components described herein may be constructed from any of a wide variety of materials that provide sufficient strength or durability, in any of a wide variety of colors, textures, and combinations. Accordingly, all such modifications are intended to be included within the scope of the present inventions. Other substitutions, modifications, changes, and omissions may be made in the design, operating conditions, and arrangement of the preferred and other exemplary embodiments without departing from scope of the present disclosure or from the spirit of the appended claims.