Abstract:
A charge air cooler is composed of a framed heat exchange core which is sealably attached in a selectively removable manner with any suitably shaped inlet and outlet ducts, and is, at the other sides thereof provided with cover panels which collectively necessitate that all of the hot charge air coming from the turbocharger pass entirely through the heat exchange core. In this regard, the heat exchange core is provided with a pair of opposingly disposed mounting frames, each of which being connected sealably to a commensurately sized and configured mounting flange of an inlet duct or an outlet duct.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This patent application claims the benefit of provisional patent application 60/550,835, filed on Mar. 5, 2004. 
    
    
     TECHNICAL FIELD 
     The present invention relates to charge air coolers of the type used in locomotive diesel engines for cooling air exiting the engine turbocharger, and more particularly to a charge air cooler having an absence of air by-pass therethrough. 
     BACKGROUND OF THE INVENTION 
     Locomotive diesel engines generally utilize a combustion intake turbocharger which provides combustion charge air for the engine, and which is rotatably powered by exhaust of the engine. After being compressed in the turbocharger, the combustion charge air is hot, and is in need of cooling. This cooling is supplied by a charge air cooler (sometimes also referred to as an after cooler), located downstream of the turbocharger and upstream of the engine air box combustion chamber. An example of a prior art charge air system  10  is depicted at  FIGS. 1 through 3 , which should be referred to respecting the following description thereof. 
     Referring firstly to  FIGS. 1 through 2 , a turbocharger  12  is interfaced with at least one prior art charge air cooler assembly  14  (two prior art charge air cooler assemblies  14 ′,  14 ″ being shown at  FIG. 1 ). The prior art charge air cooler assembly  14  includes a heat exchange core assembly  16  having a plurality of coolant tubes  14   t  arranged for a four-pass coolant path coolant tube arrangement, and having, for example, 26 to 27 coolant tubes deep, with a multiplicity of fins  14   f  connected in perpendicular relation thereto, wherein coolant (which may be liquid water or a liquid water and anti-freeze solution) circulates through the tubes via an external coolant system  18  and thereby extracts heat of the compressed charge air A from the turbocharger  12 , whereupon cooled compressed charge air A′ now passes to an engine air box combustion chamber  20 . 
     Each prior art charge air cooler assembly  14 ,  14 ′ further includes a cooler plenum  22 ,  22 ′ an inlet duct  24 ,  24 ′ integrally connected to the cooler plenum and an outlet duct  26 ,  26 ′ also integrally connected to the cooler plenum. The heat exchange core assembly  16  is slid into the cooler plenum  22 ,  22 ′ through a flanged opening  22   a  (not visible, but clearly understood from  FIG. 1 ) and then bolted thereto at a flange  22   f ,  22   f ′ of the flanged opening  22   a . Additionally, each inlet duct  24 ,  24 ′ has a flange  24   f ,  24   f ′ for being sealingly connected to a flange  28   f ,  28   f ′ of a respective outlet port  28 ,  28 ′ of the turbocharger  12 ; and each outlet duct  26 ,  26 ′ has a flange  26   f ,  26   f ′ for being sealingly connected to a respective flange  20   f , (two such flanges being present, but only flange  20   f  is shown in  FIG. 2 ) of the engine air box combustion chamber  20 . 
     Now, referring to  FIG. 2 , and with particularity to  FIG. 3 , it will be seen that in order for the heat exchange core assembly  16  to be slidable into the cooler plenum  22 ,  22 ′, a considerable amount of peripheral open space  32  exists between the heat exchange coolant core assembly and the cooler plenum. In operation, some air A B  of the hot compressed charge air A from the turbocharger  12  by-passes the heat exchange core assembly  16  and is not cooled. As a result the cooled compressed charge air A′ is actually a mixture of cooled air A C  that has passed through the heat exchange core assembly  16  and the by-pass air A B , that is A′=A C +A B . 
     To the extent by-pass air A B  exists, the prior art charge air cooler  14  does not do its job of providing cooling of the hot compressed charge air exiting the turbocharger. Additionally, to the extent that the inlet and outlet ducts are integral with the cooler plenum, ease of interconnection with external components of the engine is limited. 
     Accordingly, what is needed in the art is some configuration of a charge air cooler which eliminates by-pass air, and further which provides for easy interconnection with inlet and outlet components. 
     SUMMARY OF THE INVENTION 
     The U.S. Environmental Protection Agency (EPA) has promulgated standards which require locomotive manufacturers to comply after Jan. 1, 2005 with “Tier 2” emissions standards. As a result, there is a need to achieve about a 50% reduction in particulate emissions along with about a 30% reduction in NO x , (nitrogen oxides) emissions for locomotive two-stroke internal combustion diesel engines, dictating need for engine optimization. In accordance with the Tier 2 mandate, one aspect of the locomotive diesel engine which is subject to modification in order to comply with Tier 2 emission standards is the charge air cooler so that by-pass air is eliminated, which aspect is satisfied by the improved charge air cooler according to the present invention. 
     The improved charge air cooler according to the present invention is designed to meet Tier 2 locomotive diesel engine standards, wherein the by-pass air is eliminated; and further, the heat exchange core is directly and readily connectable to any predetermined shape of inlet and outlet duct. 
     The improved charge air cooler according to the present invention includes a heat exchange core assembly which is sealably attached in a selectively removable manner with any suitably shaped, and diametrically opposed, inlet and outlet ducts such that all of the hot charge air coming from the turbocharger passes entirely through the heat exchange core. In this regard, the heat exchange core assembly has a preferably four-pass coolant path coolant tube arrangement, as for example 24 to 25 coolant tubes deep, with a multiplicity of fins connected in perpendicular relation thereto, wherein a coolant (which may be liquid water or a liquid water and anti-freeze solution) circulates through the coolant tubing via an external coolant system and thereby extracts heat of the air passing therethrough. 
     Accordingly, it is an object of the present invention to provide an improved charge air cooler which is designed to meet Tier 2 locomotive diesel engine standards, wherein by-pass air is eliminated; and further, the improved charge air cooler is readily connectable to any predetermined shape of inlet and outlet duct. 
     This and additional objects, features and advantages of the present invention will become clearer from the following specification of a preferred embodiment. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective, exploded view of a prior art charge air system of a locomotive diesel engine, including pair of prior art charge air coolers and a conventional turbocharger. 
         FIG. 1A  is a view of a subshaft cover assembly, seen along line  1 A- 1 A of  FIG. 1 . 
         FIG. 2  is schematic view of a charge air system for a diesel locomotive, wherein a prior art charge air cooler of  FIG. 1  is utilized. 
         FIG. 3  is a detail view of the prior art charge air cooler of  FIGS. 1 and 2 , wherein by-pass charge air is permitted between the heat exchange core assembly and cooler plenum thereof. 
         FIG. 4  is a schematic view of an improved charge air system for a diesel locomotive according to the present invention, wherein an improved charge air cooler according to the present invention is utilized. 
         FIG. 5  is a detail view of the improved charge air cooler of  FIG. 4 , wherein by-pass charge air is eliminated. 
         FIG. 6A  is a perspective view of the improved charge air cooler according to the present invention. 
         FIG. 6B  is a side view of the improved charge air cooler of  FIG. 6A , showing now in particular the improved heat exchange core thereof. 
         FIG. 7A  is a perspective view of a first improved charge air cooler according to the present invention, inclusive of examples of intake and outlet ducts attached thereto. 
         FIG. 7B  is a side view of the first improved charge air cooler according to the present invention, inclusive of the examples of intake and outlet ducts attached thereto. 
         FIG. 8A  is a perspective view of a second improved charge air cooler according to the present invention, inclusive of examples of intake and outlet ducts attached thereto. 
         FIG. 8B  is a side view of the second improved charge air cooler according to the present invention, inclusive of the examples of intake and outlet ducts attached thereto. 
         FIG. 9A  is a side view of a locomotive diesel engine showing a turbocharger and one of the first and second improved charge air coolers connected to the turbocharger. 
         FIG. 9B  is a front view of the locomotive diesel engine of  FIG. 8A , now showing the turbocharger and the first and second improved charge air coolers connected to the turbocharger. 
         FIG. 10  is a graphical representation of plots of thermal effectiveness versus mass flow for a prior art charge air cooler and an improved charge air cooler according to the present invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring now to the drawings,  FIGS. 4 through 9B  depict an example of an improved charge air cooler  100  according to the present invention which is designed for meeting Tier 2 locomotive diesel engine standards for reduction of undesirable emissions, including NO x , without sacrificing fuel consumption. Such an optimized engine is, for example, an optimized General Motors Corporation Electromotive Division 710 locomotive diesel engine equipped with, among other optimizations, the improved charge air cooler according to the present invention which serves to lower the temperature of the hot, compressed charge air coming from the turbocharger by 15% over the prior art charge air cooler assembly discussed hereinabove with respect to  FIGS. 1 through 3 . 
       FIG. 4  depicts a schematic view of a charge air system  102  which utilizes the improved charge air cooler  100 . In this regard, the improved charge air cooler  100  is configured so that an improved heat exchange core  104  thereof is directly sealed with any suitably shaped inlet and outlet ducts  106 ,  108 , and is, elsewhere, provided with cover panels  110  which thereby collectively necessitate that all of the hot charge air AA coming from the turbocharger  12  pass entirely through the heat exchange core assembly so as to provide cooled charge air AA′ to the engine air box combustion chamber  20 . 
     More particularly, the improved heat exchange core  104  of the improved charge air cooler  100  includes a plurality of coolant tubes  104   t , preferably of copper, which are in intimate contact with a multiplicity of perpendicularly oriented cooling fins  104   f , also preferably of copper. In this regard, it is preferred for the coolant tubes  104   t  to be arranged 24 to 25 coolant tubes deep in a four-pass coolant path arrangement of the coolant tubes, as shown at  FIG. 6B . 
     A first tube sheet  115   a  is connected to the coolant tubes  104   t  adjacent a first end coolant fin  104   f ′, and a second tube sheet  115   b  is connected to the coolant tubes adjacent an opposite second end coolant fin  14   f ″. The cover panels  110  include a first manifold  110 M 1  which is connected to the first tube sheet  115   a  by fasteners  125  and has a single baffle  110   a , a second manifold  110 M 2  which is connected to the second tube sheet  115   b  by fasteners  125  and has a pair of baffles  110   b , a coolant inlet  110 I and a coolant outlet  100 O. In this regard, the coolant circulates along arrows W in a counterflow, four-pass coolant path (as shown at  FIG. 6B ), and is interconnected with an external coolant system  18  (as for example shown at  FIG. 4 ). The cover panels  110  further include a first side cover  110 S 1  and a second side cover  110 S 2 , both being connected to the first and second tube sheets by fasteners. The peripheries of the first and second side cover  110 S 1 ,  110 S 2  and the first and second tube sheets  115   a ,  115   b  provide a pair of generally identical, diametrically disposed mounting frames  112  having threaded fastener attachment holes  118  which are utilized to connect the inlet and outlet ducts thereto. 
     Operatively, coolant (which may be liquid water or a liquid water and anti-freeze solution) circulates through the coolant tubes  104   t  via the external coolant system  18  and thereby extracts, in cooperation with the fins  104   f , heat of the compressed charge air AA coming from the turbocharger  12 , whereupon the cooled compressed charge air AA′ now passes to an engine air box combustion chamber  20 . 
     The improved heat exchange core  104  is preferably optimized to increase tube rows by thirty-three percent over the heat exchange core assembly of the prior art charge air cooler assembly discussed hereinabove with respect to  FIGS. 1 through 3 , resulting in an increased thermal effectiveness of five percent for the improved charge air cooler over the prior art charge air cooler assembly  14 . Now, when this is added to an increase in thermal effectiveness of ten percent of the improved charge air cooler  100  over the prior art charge air cooler assembly  14 , due to elimination of by-pass air in the improved charge air cooler  100 , a total increase in thermal efficiency of fifteen percent, as mentioned hereinabove, is realized by the present invention over the prior art. 
     The improved charge air cooler  100  has a preferably symmetrical six-sided box shape. In this regard, the improved heat exchange core  104  is also preferably box-shaped, having the aforementioned mounting frames  112  at diametrically opposed sides thereof for mounting thereto the inlet and outlet ducts, respectively, via the attachment holes  118 , wherein a plurality of holes of mounting flanges  106   f ,  108   f  of each of the inlet and outlet ducts  106 ,  108 , respectively, receive threaded fasteners  116  therethrough (see by way of example  FIG. 7B ) which then threadably engage the attachment holes  118  so as to sealingly connect each mounting frame  112  to a respective one of the inlet and outlet ducts. 
     When all sides of the improved heat exchange core  104  are covered by either a duct  106 ,  108  or a cover panel  110 , the collective result is a sealed plenum  122  surrounding the improved heat exchange core  104  such that all the air flowing thereinto from the inlet duct must entirely flow out through the outlet duct, passing entirely through the improved heat exchange core, without any air by-passing the improved heat exchange core. The inlet duct  106  directs hot, compressed charge air from the turbocharger discharge to the improved charged air cooler  100 , wherein one end of the inlet duct has a suitably configured turbocharger connection flange  106   f ′ for being sealingly connected to an outlet port of the turbocharger. The outlet duct  108  directs cooled, compressed charge air from the improved charge air cooler  100  to the engine air box combustion chamber  20 , wherein one end of the outlet duct has a suitably configured chamber connection flange  108   f ′ for being sealingly connected to a port of the engine air box combustion chamber. 
     Since the shape of the improved charge air cooler  100  is symmetrical, the inlet and outlet ducts  106 ,  108  may be connected to the improved charge air cooler at selected opposing sides thereof. In this regard, the improved charge air cooler  100  may be connected in any direction to the turbocharger  12  and the engine air box combustion chamber  20 , via any suitable ducting  106 ,  108 , without altering its heat exchange characteristics. Therefore, the air direction across the improved heat exchange core  104  can be one way, or the opposite way, as desired for a particular installation, wherein the coolant flows in a perpendicular plane with respect to either direction of air flow. 
     The inlet and outlet ducts  106 ,  108  have been designed to improve air flow distribution to and from the improved charge air cooler  100 , and thereby assist in the charge air cooling efficiency thereof. The inlet and outlet ducts  106 ,  108  also serve to support the charge air cooler  100 ; accordingly, the inlet and outlet ducts are configured and enhanced to withstand vibrations and shock which can cause fatigue structural failure of previous designs of the prior art charge air cooler assembly as recounted above with respect to  FIGS. 1 through 3 . Additionally, the improved charge air cooler  100  and the inlet and outlet ducts  106 ,  108  have been configured to provide ease of installation to the locomotive diesel engine, and to withstand misalignment during the installation process. 
     In that it is preferred for the turbocharger  12  to have two outlet ports, it is therefore preferred to provide two improved charge air coolers  100 , a first improved charge air cooler  100 ′ as shown at  FIGS. 7A and 7B  which interfaces with a first outlet port  28  of the turbocharger  12  (see  FIG. 1 ), and a second improved charge air cooler  100 ″ as depicted at  FIGS. 8A and 8B  which interfaces with a second outlet port  28 ′ of the turbocharger (see  FIG. 1 ). It will be seen that the first improved charge air cooler  100 ′ has associated therewith a first inlet duct  106 ′ and a first outlet duct  108 ′. Additionally, it will be noted that the second improved charge air cooler  100 ″ has associated therewith a second inlet duct  106 ″ and a second outlet duct  108 ″. 
     Referring now to  FIGS. 9A and 9B , a typical installation example of the first improved charge air cooler  100 ′ (and its associated first inlet and outlet ducts  106 ′,  108 ′) and the second improved charge air cooler  100 ″ (and its associated inlet and outlet ducts  106 ″,  108 ″) are shown with respect to a turbocharger  12  and engine air box combustion chamber  20  of a locomotive diesel engine  130 , such as, for example, an optimized General Motors Corporation Electromotive Division Model 710 diesel engine. 
     Referring now to  FIG. 10 , a pair of plots of thermal effectiveness versus mass flow, wherein plot  124  is for the improved charge air cooler  100  according to the present invention, and plot  126  is for the prior art charge air cooler assembly discussed hereinabove with respect to  FIGS. 1 through 3 . It will be seen that the improved charge air cooler  100  is improved by at least ten percent over the prior art charge air cooler assembly. 
     To those skilled in the art to which this invention appertains, the above described preferred embodiment may be subject to change or modification. Such change or modification can be carried out without departing from the scope of the invention, which is intended to be limited only by the scope of the appended claims.