Abstract:
A low profile generator mount for large vehicles, such as tractor trailer combinations, utilizes the space below the door of the cab. The mount is an enclosure connected to the frame and housing a compact diesel engine and generator combination with the exterior of the mount capable of being in the form of steps for ingress into the cab, or formed to assimilate a conventional truck mounted storage box.

Description:
RELATED APPLICATION 
     This invention is a continuation-in-part of application Ser. No. 09/603,725 filed Jun. 23, 2000, now U.S. Pat. No. 6,677,684 the content of which is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to auxiliary power generators and, in particular, to a compact auxiliary power generator having a generator assembly coupled directly to a diesel engine for use in mobile applications, such as large trucks. 
     BACKGROUND OF THE INVENTION 
     Semi-truck tractor trailers frequently employ the use of an auxiliary generator to meet electrical requirements when the main engine is not running. Tractor trailers having a “bunk” or “sleeper” cab area are common and most interstate fuel stations permit the drivers of such vehicles to sleep in their cab. The passenger area of the truck may include convenience items such as a television, VCR, refrigerator, air conditioner, coffee maker, even a microwave oven. While such items may run on direct current provided by an engine mounted alternator, or even alternating current by use of an inverter, the truck engine must be running. Idling laws now prohibit the running of the main engine for prolong periods of time. However, the time and cost savings of keeping the driver near the vehicle while at rest are obvious and ancillary benefits include security as the operator does not leave the vehicle unattended. 
     A problem with the use of auxiliary generators is directed to size, weight, and placement. The size of an auxiliary generator is critical for if the overall dimensions are too large, there will be insufficient areas on a truck for which to place the auxiliary generator. For instance, it is not possible to place an auxiliary engine within the existing main engine compartment. Placement of an auxiliary engine on the frame rails is a known alternative, however conventional auxiliary generators employ baseplates making the size, weight, and subsequent placement a problem. 
     Generators also have a problem with vibration caused by misalignment. Installations commonly address misalignment by mounting the engine and the generator set on a heavy baseplate, the total weight of which may easily approach 500 lbs. By mounting both units on a baseplate the misalignment of the belt drive between the engine and generator is prevented. However, the mounting of a generator and an engine on a baseplate results in a large usage of space due to the separation between the components. 
     The use of gasoline engines to power a generator is also well known. Gasoline engines are lighter in weight and smaller in size when compared to a diesel engine of the same horsepower. However, gasoline is a very volatile fuel and when a gasoline engine is placed into the confines of a container or step box, the gasoline engine must be made either “spark proof” or it will present a lethal environment that can create an explosion. Further, when used on a diesel powered tractor trailer, a separate fuel tank is required and grounding becomes critical since any stray spark can ignite gasoline. 
     The Applicant is a well known assembler of diesel engine/generators packages and has been awarded patents for various arrangements. U.S. Pat. Nos. 6,047,942 and 5,765,805 granted to the Applicant disclose the use of a combination engine/generator that is lightweight and of a novel space saving configuration. 
     Thus what is found lacking in the art is a low profile generator set that employs a diesel engine in a configuration that minimizes space, weight, vibration and includes an installation mount integrating the generator set with a diesel powered tractor trailer. 
     DESCRIPTION OF THE PRIOR ART 
     An integral engine generator set that may be used in this invention is disclosed in U.S. Pat. No. 5,765,805 to G. W. Kennedy, the inventor here. The disclosure of this patent is incorporated herein by reference. 
     The integral engine generator set described in the patent utilizes a bracket interposed between the engine and generator for direct coupling of the components. The inspection plate of the engine is replaced by the bracket and the generator is bolted to the other side of the bracket. The bracket eliminates the need for a common baseplate and a belt tensioner. The engine and bracket may have isolation mounts for support or the engine, alone, may be mounted to the vehicle. 
     Base plates for motors are old and well known in the prior art as exemplified by U.S. Pat. No. 2,662,988. Also, mounting brackets are conventional as shown by Credle, Jr. in U.S. Pat. No. 4,441,684. 
     SUMMARY OF THE INVENTION 
     The instant invention is a unitary combination engine generator set combined with a support housing that is incorporated into the design of the vehicle in which it is mounted. 
     The instant invention is an engine/generator assembly designed specifically for semi-truck tractor trailer applications. The assembly employs a rigid integral diesel engine/generator with a synchronized belt drive therebetween. The assembly is positionable within an enclosure by employing a horizontally disposed engine providing a low profile and securing the assembly within an enclosure to the chassis of the truck, in a similar manner as an auxiliary fuel tank. 
     An objective of this invention is to provide a diesel engine/generator set having a very low profile for placement within an existing compartment of a vehicle. 
     Another objective of this invention is to provide a diesel engine/generator set that is positionable within a conventional low profile step securable to a truck chassis. 
     Still another objective of this invention is to provide a storage container for an auxiliary generator that conceals the contents from theft and adverse environmental conditions. 
     Another objective of this invention is to provide a low profile mount for a diesel engine/generator set that minimizes vibration in the support vehicle. 
     Yet another objective of this invention is to provide a low profile mount which permits easy access to the engine and generator set. 
     Yet still another objective of this invention is to provide a generator storage box that further operates as a step. 
    
    
     Other objectives and advantages of this invention will become apparent from the following description taken in conjunction with the accompanying drawings wherein are set forth, by way of illustration and example, certain embodiments of this invention. The drawings constitute a part of this specification and include exemplary embodiments of the present invention and illustrate various objectives and features thereof. 
     BRIEF DESCRIPTION OF THE FIGURES 
     FIG. 1 is a perspective view of the low profile generator mount installed on a large truck; 
     FIG. 2 is a perspective of the diesel engine/generator set; 
     FIG. 3 is a perspective of the mount of FIG. 1 with the diesel engine/generator exposed; 
     FIG. 4 is another embodiment of the low profile generator mount; 
     FIG. 5 is a prospective of the rear of the truck step; 
     FIG. 6 is a side view of the truck step; 
     FIG. 7 is a side view partially in section illustrating the low profile generator coupled to the truck radiator for cooling purposes; 
     FIG. 8 is a partial perspective view illustrating the low profile generator coupled to a remote radiator. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Now referring to FIGS. 1 and 2 which shows an illustration of a large truck  1  having a chassis, or frame, in which an external fuel tank  5  is typically mounted between the cab  7  and the truck bed  9  or trailer, not shown. The size and height of the truck normally requires steps located beneath the door  11  to gain entry to the cab  7 . In some truck designs, the steps are faired into the external fuel tanks for aesthetics and aerodynamics. In other designs the tanks are behind the doors of the cab and the steps are separate. 
     In the first embodiment, the generator set of the instant invention is incorporated within a box  40  or step structure of the truck. The step structure  40  is made of metal attached to the truck frame  3  and extends below the frame. The step structure has a lower step  42 , extending horizontally closest to the ground, with a non-slip surface  44  extending between side walls  46  and  48  at each end of the step. The side walls form an integral portion of the storage box  40  which is attached to the truck frame by bolts, welding, rivets, and the like. The step  42  may be attached to the brackets in the same manner or made from a single piece of metal further forming a platform for mounting of the generator within the storage box. The step  44  may be a solid planar metal sheet with a non-slip tread formed in the upper surface or an open mesh material. The step  42  extends outwardly from the enclosure sufficiently to provide a safe footing. 
     A vertical cover  50  is rotatably attached to the brackets by a hinge  52  at the upper edge. The cover forms the front wall of the enclosure. The lower edge  54  of the cover  50  may have a latch mechanism  56  to cooperate with the step  42  to releasably hold the cover  50  in place in the closed position. When closed, the cover forms the vertical riser between the lower step and the upper step. The height of the vertical riser is limited to the distance an average person can step, e.g. approximately 14 to 17 inches. The hinged cover  50  provides access to the generator set while providing protection for both the machinery and the operators. The upper surface  58  of the cover  50  may form a second step if necessary to provide egress into the cab  11 . Another fixed vertical cover opposite the front wall forms the back wall  51  of the enclosure. The wall  51  has perforations  53  for ventilation. In one embodiment (not shown), a hinge may be at the lower edge of the side wall and the latch near the upper step. Alternatively, the top may be removable such as those found on Peterbilt trucks. In a preferred embodiment, the upper surface  58  of the enclosure is attached to the side walls  60  and  62  to form the upper step. Kenworth trucks typically include a hinged cover for storage boxes. 
     Now referring to FIG. 3, there is shown a conventional diesel engine  100 , such as manufactured by the Kubota Corporation, having a horizontally disposed cylinder  112  and an integral generator  142  located on opposite sides of the crank case  116 . This orientation is necessary to accommodate the internal space requirements existing in the step  42 . In this installation, the piston reciprocates parallel to the step surface  44 . 
     The engine, shown in FIG. 3, is self contained having a radiator  113 , starter  114 , crank case  116 , air cleaner  118 , and fuel injections system (not shown). The crank case  116  includes isolation mounts  122  mounted to the crank case by the use of support brackets. 
     A support bracket  136  is constructed from an aluminum plate having a thickness of about ⅜ inch with a first side surface  138  securable to the engine and a second side surface  140  available for securing the generator  142 . The bracket  136  may be through-bolted to the engine and generator or otherwise fixed to provide a rigid engine/generator set. A second set of isolation mounts  144  is secured to the bracket  136  providing a structure for mounting inside the storage box  40 . 
     The low profile generator set has the approximate dimensions of 28 inches length, 17 inches height and 16 inches deep. The preferred engine  100  is a one cylinder liquid cooled Kubota diesel engine turning a generator of 3.5 kilowatts capacity at 120 volts and 30 amps. In another embodiment having a height approximately 14 inches, the engine radiator  113  and cooling fan  115  are located outside the enclosure and connected to the engine by the requisite hoses and wires, as shown in FIGS. 5 through 8. Hose and wire connections allowing the remote mounted radiator and/or fan are well known in the art and therefore a detailed description will be omitted. The radiator is secured to the enclosure wall by the use of isolation supports or rubber biscuits  111 . The rubber biscuits  111  space the radiator apart from the enclosure a predetermined distance creating a relief space. The fan  115  is positioned outboard the radiator wherein the fan draws air from the relief space and through the radiator  113 . In addition, the enclosure preferably includes a discharge opening or perforated back wall  51  wherein the fan draws air from the enclosure with the relief space providing additional air if the enclosure lacks sufficient air displacement. In this position, the fan serves the dual purpose of extracting heated air from the enclosure and providing air flow across the radiator. Alternatively, the generator engine can access the primary cooling system of the truck. In this arrangement, the radiator and fan can be removed and fluid circulated through the truck radiator system wherein by its shear volume may not require an auxiliary fan for cooling of the smaller engine coupled to the generator. 
     FIG. 4 sets forth another embodiment wherein the generator set may be mounted in a box  70  having a hinged top  72 . The box  70  would appear that of a conventional storage box found on trucks and may, or may not, operate as a step. The top  72  may be opened to gain access to the generator set rotating along a hinge and secured closed by a latch mechanism  74  to releasably connect the top step to the remainder of the box. In both embodiments of the enclosure, there is adequate ventilation to permit dissipation of heat and engine air intake. 
     It is to be understood that while a certain form of the invention is illustrated, it is not to be limited to the specific form or arrangement of parts herein described and shown. It will be apparent to those skilled in the art that various changes may be made without departing from the scope of the invention and the invention is not to be considered limited to what is shown and described in the specification and drawings.