Patent Publication Number: US-8534198-B2

Title: Locomotive engine enclosure and method for servicing locomotive engine

Description:
TECHNICAL FIELD 
     This patent disclosure relates generally to diesel-electric locomotives and, more particularly, to an engine enclosure for a locomotive. 
     BACKGROUND 
     Diesel-electric locomotives traditionally employ a high power diesel internal combustion engine to rotate an electric generator, which in turn provides electric power to drive the locomotive&#39;s fraction motors and to power other components. In a so-called line haul locomotives, the desired acceleration and pull force required to move rolling stock and cargo weighing hundreds of tons requires a large amount of power. For this reason, the diesel engine in a line haul locomotive often has a rated power output exceeding 4,000 brake horsepower (bhp). 
     Large diesel engines perform well in terms of emissions and fuel efficiency at or near the rated power output. But the duty cycle typically experienced by a line haul locomotive also requires the engine to idle for long periods of time or maintain low train speeds, which results in the diesel engine often operating at a low power output. During operation in low power output modes, the large diesel engine is relatively less effective in terms of emissions and fuel efficiency. 
     Several locomotive manufacturers in the U.S. have begun to commercialize new locomotives which are powered by multiple diesel engines. For instance, multi-engine “genset” locomotives have been developed for use in so-called switcher locomotive applications. Switcher locomotives are typically used in a rail yard to move cars around when assembling and disassembling trains. The relatively recently commercialized switcher locomotives are called genset locomotives because each engine is connected to device a respective electric generator. The multiple engines are typically mounted together on a separate frame as an independent power pack in a fashion similar to a generator set used in backup power or remote power applications. Each genset is individually mounted to the locomotive deck. Genset locomotives can have two to four separate power packs, which may be identical to one another or which may include a larger engine in combination with one or more smaller engines. Having multiple engines allows the operation of just a single engine during idling and low power output. The relatively small, single engine operated during low power output can operate more efficiently than a very large diesel engine at that same power output. A low power output will be a much higher percentage of the rated power of a small engine than it would be for a very large engine, and efficiency is generally a function of the percentage of rated power output. When the locomotive requires high power output, all of the engines can be operated simultaneously to produce maximum power. Thus, with the application of multiple engines, it is possible to reach a new compromise for locomotive propulsion where power can be provided almost as effectively, in terms of emissions and fuel efficiency, at low power output as at high power output. 
     The use of multiple engines and alternators in a single locomotive, however, creates a challenge for packaging of all the different components into the locomotive&#39;s engine compartment. Moreover, the dense packaging of engine and other locomotive components within the engine compartment creates challenges when attempting to access various components for repair and service. 
     SUMMARY 
     The disclosure describes, in one aspect, a locomotive. The locomotive includes a frame having a longitudinally extending centerline. The frame is supported by two trucks having traction motors associated therewith, which are operable to drive one or more wheels configured to engage a railroad. An engine compartment has two sidewall structures extending parallel to the centerline, an inboard end structure and a rear end structure, which extend perpendicular to the centerline. An engine enclosure is defined between the frame, the two sidewall structures, and the inboard and rear end structures. At least one top hatch is connected to the engine compartment and disposed to cover a top opening of the engine enclosure. At least one engine connected to a generator is disposed within the engine enclosure. The generator is configured to provide electrical power to the traction motors. A removable cap is generally box-shaped and extends across a portion of the top opening of the engine enclosure adjacent the at least one top hatch and across a portion of each of the two sidewall structures. An engine pit opening is defined in the engine enclosure and exposed when the removable cap has been removed. The engine pit opening is sufficiently large to accommodate the at least one engine being lifted out of the engine enclosure through the engine pit opening. The engine pit opening is further defined by two side edges extending parallel to the centerline along the sidewall structures, each of the two side edges disposed at a clearance height that is lower than an overall height of the engine compartment. 
     In another aspect, the disclosure describes an engine compartment for housing one or more engines of a machine. The engine compartment includes two sidewall structures extending parallel to a longitudinal centerline of the engine compartment. An inboard end structure and a rear end structure extend perpendicular to the centerline. An engine enclosure is defined between the frame, the two sidewall structures, and the inboard and rear end structures. At least one top hatch is disposed to cover a top opening of the engine enclosure. At least one engine is disposed within the engine enclosure. A removable cap that is generally box-shaped extends across a portion of the top opening of the engine enclosure adjacent the at least one top hatch and across a portion of each of the two sidewall structures. An engine pit opening is defined in the engine enclosure and exposed when the removable cap is removed. The engine pit opening is sufficiently large to accommodate the at least one engine being lifted out of the engine enclosure through the engine pit opening. The engine pit opening is further defined by two side edges extending parallel to the centerline along the sidewall structures, each of the two side edges disposed at a clearance height that is lower than an overall height of the engine compartment. 
     In yet another aspect, the disclosure describes a method for servicing a locomotive engine. The method includes removing one or more top hatches of an engine compartment of the locomotive, and disconnecting and removing various components of the locomotive that are installed on a top portion of the engine compartment. An engine pit opening is exposed through a top of the engine compartment. The engine pit opening has sufficient clearance to allow the lifting and removal of a locomotive engine from the engine compartment. The engine pit opening is at least partially defined by two side edges extending parallel to a centerline of the locomotive, each of the two side edges being disposed at a clearance height that is lower than an overall height of the engine compartment. The locomotive engine is disconnected from other components and systems of the locomotive, and is then lifted and removed from the locomotive through the engine pit opening. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a locomotive in accordance with the disclosure. 
         FIG. 2  is a partially disassembled view of portion of a locomotive&#39;s engine compartment in accordance with the disclosure. 
         FIG. 3  is a top view of a locomotive engine installed in a compartment in accordance with the disclosure. 
         FIG. 4  is a side view and  FIG. 5  is a partially disassembled perspective view of a portion of the engine compartment of a locomotive in accordance with the disclosure. 
         FIG. 6  is a perspective view of the engine compartment for an alternative embodiment of a locomotive in accordance with the disclosure. 
         FIGS. 7 and 8  are views from different perspectives of a removable cap for a locomotive in accordance with the embodiment shown in  FIG. 6 . 
         FIG. 9  is a partially disassembled view of a locomotive during an engine extraction or installation process in accordance with the disclosure. 
         FIG. 10  is a perspective view of the engine compartment of another alternative embodiment for a locomotive in accordance with the disclosure. 
         FIG. 11  is a perspective view of a removable cap for a locomotive in accordance with the embodiment shown in  FIG. 10 . 
         FIG. 12  is a cross section through a portion of the engine compartment shown in  FIG. 10 , and  FIG. 13  is a detail cross section thereof. 
         FIG. 14  is a flowchart for a method in accordance with the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     This disclosure relates to locomotives having one or more engines associated therewith. More particularly, the disclosure relates to a cooling system for locomotives that is configured to be removed such that access is provided for engine service or replacement. While the arrangements in accordance with alternative embodiments are illustrated in connection with a locomotive, the arrangements disclosed herein have universal applicability in various other types of machines as well. The term “machine” may refer to any machine that performs some type of operation associated with an industry such as mining, construction, farming, land or marine transportation, mobile or stationary power generation or any other industry known in the art. For example, the machine may be an earth-moving machine, such as a wheel loader, excavator, dump truck, backhoe, motor grader, material handler or the like. Moreover, mobile or stationary electrical power generation machines, such as gensets, may be used. 
     A locomotive  100  is shown in  FIG. 1 . In the illustration of  FIG. 1 , an exemplary locomotive is shown but other types of locomotives are also contemplated. The locomotive  100  includes a frame  102  supported by two truck assemblies  104 . Each truck assembly  104  is pivotally connected to the frame  102  and includes three wheel axles  106 , each of which is powered by an electric traction motor (not shown) as is known. The frame  102  also includes a fuel tank  108  and couplers  110  disposed on either end. 
     On a top side, the frame  102  includes an operator compartment  112  disposed adjacent an electrical switchgear compartment  114  that houses various electrical power distribution and transformation components (not shown). An generator compartment  116  houses a main generator (not shown), which is arranged to provide DC electrical power to drive the traction motors. An engine compartment  118  is disposed adjacent the generator compartment  116 . The engine compartment  118  includes at least a large diesel engine (not shown) connected to the generator, and a genset having a smaller diesel engine. Radiators  120  that are convectively cooled by an airflow provided by fans  122  are disposed on the upper portion of the engine compartment  118 . 
     Various access panels or doors  126  are provided along the sides of the engine compartment  118  to provide access to the engines for service. However, certain engine service operations may become time consuming or may even be impossible to perform by the relatively limited access to internal components provided through the doors  126 . Accordingly, alternative access to the engines within the engine compartment  118  would be beneficial to the speed and the ability to service the engines. 
     A first embodiment of an engine compartment  218  configured to provide easy access to the engines of the locomotive  100  is from a side perspective in  FIG. 2  and from a top perspective in  FIG. 3 . Certain components, such as the doors  126  and top hatches  128  have been removed, and certain components such as the larger of the two diesel engines has been omitted in the illustrations of  FIG. 2  and  FIG. 3  for clarity. In reference to  FIG. 2 , the engine compartment  218  includes two sidewall structures  220 , an inboard end structure  222  and an end structure  224 . A genset  226  includes an engine  228  and a generator  229  (generator shown in  FIG. 9 ). The generator connected to engine  228  has been omitted from the illustrations, but its positioning and operable association with engine  228  is well known in the art. For example, the genset  226  may be a C18 genset manufactured by Caterpillar, Inc. of Peoria, Ill. 
     The engine  228  may be an inline-6 cylinder, water cooled diesel engine. Cooling water circulating through the engine  228  during operation is provided to radiators  230  that are disposed along the sides of a cooling enclosure  232 . During operation, air is drawn into the cooling enclosure  232  through the radiators  230  by a fan  234 , which then expels the air through the top side of the enclosure  232 . The fan  234  is installed in a top hatch  236 . 
     Turning now to the illustration of  FIG. 3 , the fan  234  and top hatch  236  have been removed to expose an engine pit opening  238 . From this top view, it can be seen that the engine pit opening  238  is sufficiently long and wide to permit the vertical lifting of the engine  228  out of the engine compartment  218 . In this way, when requiring service of the engine  228  that would otherwise be hindered by the structures surrounding the engine  228  within the engine compartment  218 , the engine  228  may be disconnected from the various mechanical, electrical and fluid connections. Thereafter, the electrical connections to the fan  234  may be severed and the top hatch  236  removed to expose the engine  228  through the engine pit opening  238 . With the engine disconnected and exposed, the engine  228  may be simply lifted by an overhead crane (not shown), serviced, and reinstalled or replaced by a standby unit. In this way, service and maintenance of the locomotive  100  may be expedited. 
     In reference now to  FIG. 4 , which is a partial section view of the engine compartment  218 , and to  FIG. 5 , which has certain panels removed, additional and optional structures may be seen. In reference to  FIG. 4 , an intermediate hatch  240  can be seen extending horizontally between an engine enclosure  242  and the cooling enclosure  232 . The intermediate hatch  240 , when one is installed, covers substantially the entire engine pit opening  238  ( FIG. 3 ) and is removed to provide access to the engine  228 . When installed, the intermediate hatch  240  provides a barrier for convective heating of the cooling enclosure  232  and the various components found therein from heated air wafting from the engine  228  during operation. 
     In reference to  FIG. 5 , an optional exhaust stack  244  is shown that extends through both the intermediate hatch  240  and the top hatch  236  to expel exhaust gas during operation of the engine  228 . As shown, a pipe that includes a muffler  246  extends vertically upward through aligned openings in the hatches  236  and  240 . When the stack  244  is installed, optional seals to prevent air at different temperatures mixing between the engine enclosure  242  and the cooling enclosure  232  may be used at the stack openings formed in the hatches  236  and  240 . 
     When the embodiment of an engine compartment  218  is used, as shown in  FIGS. 2-5 , a service procedure to remove and/or replace the engine  228  from the engine enclosure  242  may be carried out by first disconnecting the electrical connections to the fan  234 , the fluid connections to the radiators  230  and, if installed, the gas connections to the stack  244 . Thereafter, the top hatch  236  along with the fan  234  can be removed, followed by the removal of the intermediate hatch  240  to expose the engine  228  from the top through the engine pit opening  238 . Thereafter, the engine may be disconnected from the locomotive  100  and withdrawn from the locomotive  100  by an overhead crane (not shown). This procedure is advantageous because it provides unhindered access to the components of the engine  228  after it has been removed, and represents an improvement over the limited access afforded through the door openings in the sidewall structures  220  while the engine  228  is still connected in the engine enclosure  242 . 
     In the description that follows, structures and features that are the same or similar to corresponding elements and features already described are denoted by the same reference numerals as previously used for simplicity. Accordingly, an alternative embodiment of an engine compartment  318  is shown in  FIG. 6 . The engine compartment  318  includes sidewall structures  220 , an inboard end structure  222  and an end structure  224 . In this embodiment, the end structure  224  is considerably shorter than the corresponding structure shown in  FIG. 2  in that a portion of the end structure  224  is defined on a removable cap  320  that covers the engine enclosure  242 . 
     The removable cap  320 , which is best shown from different perspectives in  FIGS. 7 and 8 , includes a rear structure portion  322  that forms part of the rear structure profile of the locomotive when the cap  320  is installed as part of the engine compartment. The removable cap  320  further includes an inner structure plate  324  that mates with the remaining engine compartment and two radiators  230  disposed at angle that follows the profile of the radiators  230  of the main engine, as shown in  FIG. 6 . The removable cap  320  has a generally rectangular cuboid or box shape. A fan opening  326  is configured to accommodate the fan  234  ( FIG. 5 ), and an exhaust stack opening  328  accommodates the exhaust stack  244  (FIG.  5 ). The removable cap  320  further includes inclined heat shields  330  that substantially isolate the radiators  230  from heated air that rises from the engine  228  during operation. 
     From a functional standpoint, the removable cap  320  supports the fan  234  and radiators  230  in a fashion similar to the engine compartment  218  and hatches  236  and  240  discussed previously relative to the embodiment shown in  FIGS. 2-5 . However, the incorporation of a removable rear structure portion  322  of the rear structure  224  facilitates the removal of the engine  228  from the engine enclosure  242 . More specifically, as best shown in  FIG. 9 , the engine  228  can be lifted from the engine enclosure  242  through the engine pit opening  238 , which has edges  419  extending along the sidewalls of the engine enclosure that are disposed at a clearance height, h, which in the illustrated embodiment is about 40% lower than a total height, H, of the engine compartment  318 . In this way, the locomotive  100  may be more easily serviced in facilities having lower overhead cranes or overhead work clearance. In the illustration of  FIG. 9 , the engine  228  is shown in a partially withdrawn position as it passes through the engine pit opening  238 . 
     When lifting the removable cap  320  from the locomotive  100 , overhead crane cables (not shown) can be connected to lift points  332  and lift the removable cap  320  after the appropriate electrical, fluid and gas connections have been disconnected as previously discussed. When the removable cap  320  is installed onto the locomotive  100 , it may be secured thereto by use of any appropriate means, such as threaded fasteners passing through openings  334 . A rectangular cuboid or box space that is open at least on the sides and top of the engine enclosure  242  permits access to remove the engine  228  from the engine enclosure  242  while also reducing the clearance height that the engine must be lifted to clear the locomotive. 
     An alternative embodiment for an engine compartment  418  is shown in  FIGS. 10-13 . In this embodiment, structures or features that are the same or similar to corresponding structures and features previously described are denoted by the same reference numerals previously used for simplicity. The engine compartment  418  includes sidewall structures  220 , an inboard end structure  222  and an end structure  224 . Unlike the engine compartment  318  as shown, for example, in  FIG. 6 , the end structure  224  of engine compartment  418  is similar to the end structure of engine compartment  218  as shown in  FIG. 2 . In other words, the end structure  224  has a length comparable to the overall height of the engine compartment  418 . 
     Although the end structure  224  is higher for the engine compartment  418  than it is for the engine compartment  318 , the engine compartment  418  includes a removable cap  420  that is structured generally similarly to the removable cap  320 , as shown in  FIGS. 7 and 8 . The removable cap  420  also has a generally rectangular cuboid or box shape. More specifically, as shown in  FIG. 11 , the removable cap  420  includes a rear structure panel  422  that is disposed adjacent the rear structure  224  when the cap  420  is installed as part of the engine compartment  418 . The removable cap  420  further includes an inner structure plate  324  that mates with the remaining engine compartment and two radiators (not shown) disposed at an angle that follows the profile of the radiators  230  of the main engine, as shown in  FIG. 10 . A fan  234  is connected at the top of the removable cap  420  and configured to convectively cool the radiators as in the previous embodiments. 
     The removable cap  420  further includes a flange  424  disposed along the upper, laterally extending edge of the inner structure plate  324  such that the overall profile of the engine compartment appears uninterrupted when the removable cap  420  is installed. As best shown in the cross sections of  FIGS. 12 and 13 , the flange  424  is formed as part of the inner structure plate  324  and extends perpendicularly away therefrom such that it rests on a top engine enclosure structure  426 . The flange  424  is connected to the top engine enclosure structure  426  by fasteners (not shown) extending through bores  428 . In this way, any gaps that may remain in the vertical direction between the removable cap  420  and the remaining structure of the engine compartment  418  will be on the lower or sandbox end of the enclosure and will not detract from the aesthetic appearance of the locomotive engine enclosure. 
     From a functional standpoint, the removable cap  420  supports the fan  234  and radiators  230  in a fashion similar to the engine compartment  218  and hatches  236  and  240  discussed previously relative to the embodiment shown in  FIGS. 2-5 . Yet, even with the increased height, the end structure  224  will not substantially interfere with the removal of the engine  228  through the engine pit opening  238 . After the engine  228  has been lifted beyond a top clearance level at the side edges  419  (also shown in  FIG. 9 ) of the engine pit opening  238 , the engine may be laterally moved away from the locomotive even before the end structure  224  has been cleared. In other words, the engine removal can be accomplished with the relative ease previously described relative to the removable cap  320  as shown in  FIG. 9 . In this way, the locomotive  100  may be more easily serviced in facilities having lower overhead cranes or overhead work clearance. In the illustration of  FIG. 9 , the engine  228  is shown in a partially withdrawn position as it passes through the engine pit opening  238 . 
     Industrial Applicability 
     The present disclosure is applicable to locomotives having multiple engines driving generators or gensets. The various embodiments described herein generally include structures disposed above an engine that can be removed such that the engine can be extracted from the locomotive. Given the relatively tight clearances around the engines disposed in the engine compartment of the locomotive, engine extraction can shorten the time spent servicing the engine by providing easy access to engine components. 
     A flowchart for a method of servicing an engine of a locomotive is shown in  FIG. 14 . Certain engine service procedures may be conducted that require access to hard-to-reach engine components when the engine is installed in the locomotive. In such instances, a service procedure may begin by removing one or more top hatches of an engine compartment of the locomotive at  502 . Various components of the locomotive, such as fans, radiators and the like that are installed on the top of the engine compartment are disconnected and removed at  504 . The removal of these components exposes an engine pit opening at  506 . The engine pit opening is an opening through the top of the engine compartment having sufficient clearance to allow the lifting and removal of a locomotive engine from the engine compartment. 
     The engine exposed from the top through the engine pit opening may be disconnected from other components and systems of the locomotive, lifted through the engine pit opening and removed from the locomotive at  510 . Following the completion of service procedures on the engine removed or, alternatively, replacement of the engine, the engine is replaced in the engine compartment by lowering into position through the engine pit opening at  514 . The engine is reconnected to the appropriate components and systems of the locomotive at  516 , various other components removed at  504  are reinstalled and reconnected at  518 , and the top hatches of the engine compartment are replaced at  520  to complete the service procedure. 
     It will be appreciated that the foregoing description provides examples of the disclosed system and technique. However, it is contemplated that other implementations of the disclosure may differ in detail from the foregoing examples. All references to the disclosure or examples thereof are intended to reference the particular example being discussed at that point and are not intended to imply any limitation as to the scope of the disclosure more generally. All language of distinction and disparagement with respect to certain features is intended to indicate a lack of preference for those features, but not to exclude such from the scope of the disclosure entirely unless otherwise indicated. 
     Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context.