Abstract:
A multi-paneled cooling module adapted to be mounted to an engine exterior protects electronic components such as sensors and associated wiring from heat loads of the engine and/or other heat generating engine devices. The module is formed of wall and ceiling panels having a relatively high thermal conductivity, such as aluminum. The cooling module, which includes strategically situated integral coolant passages within several of its panels, is adapted to protect all enclosed electronic components, including electronic pressure sensors, an EGR valve, and all associated wiring and wiring harnesses. For example, the sensors, harnesses, and valve components associated with and proximal to an EGR venturi may be fully protected from overheating, in spite of exposure of those components to massive heat loads generated by the venturi. Finally, the cooling module may incorporate additional cooling accommodation for hydraulic oil cooling if, for example, the EGR valve is hydraulically actuated.

Description:
TECHNICAL FIELD 
     This disclosure relates generally to a system and method for protecting electronic components attached to engines subjected to deleteriously high temperatures and heat loads. More particularly, the disclosure relates to liquid cooled structural modules adapted to enshroud and shield such components from heat. 
     BACKGROUND 
     Exhaust emissions of internal combustion engines, particularly diesel engines, contain regulated exhaust constituents, mainly nitrogen oxides (NOX) and soot particles. Such emissions are limited by federal laws and regulations in most countries. One common way to reduce nitrogen oxide emissions is to use an exhaust gas recirculation (EGR) system wherein a part of the exhaust gas is purposely returned to the combustion chamber. This action leads to lower peak combustion temperatures, which in turn reduces formation of NOX. 
     The typical modern diesel EGR system employs a so-called high pressure loop (HPL) system wherein a portion of engine exhaust is removed upstream of a turbine of a turbocharger. A pressure differential between exhaust and intake manifolds may be maintained to be positive in order to provide adequate EGR flow upon demand; the pressure differential may be controlled by various means, such as a variable geometry turbine or a backpressure valve. In some embodiments, the exhaust portion flows through an EGR cooler provided with a coolant medium, such as engine coolant or ambient air. From the cooler, the EGR flows through an EGR conduit into an EGR venturi tube (herein called a venturi) adapted to provide control feedback for managing the EGR flow rate. An EGR control valve directly controls the EGR flow rate, as the recirculated exhaust gas mixes with so-called cooled charge air before being inducted into the engine via the intake manifold. 
     In a heavy duty diesel engine environment, the EGR venturi can heat up to temperatures beyond designed operational limits of various electronic pressure sensors and associated wiring, particularly when the engine is operated at higher loads. Many solutions have been offered, including one provided in U.S. Pat. No. 7,921,830, which discloses a venturi containing liquid cooled internal chambers to manage operating temperatures within the physical venturi structure. The solution offered is relatively expensive, and may not be as effective as desired. A second solution is offered in U.S. Pat. No. 6,415,757, which discloses a double-walled chamber ( FIG. 5 ) adapted to enclose temperature sensitive electronics, and to circulate cooling fluid through the chamber. A simpler and more conveniently assembled solution is desired. 
     SUMMARY OF THE DISCLOSURE 
     In one aspect of the disclosure, a cooling module protects from overheating at least one electronic engine component situated proximally to the engine. The module, adapted to be secured to the exterior of an engine, includes a plurality of thermally conductive panels, and at least one panel includes an integral tubular coolant passage. The panels are joined together to form an enclosure defined by interior surfaces of the panels. The joined panels collectively define individual walls and a ceiling of the module to form a plurality of enclosing side walls and an enclosing ceiling. A floor and at least one side wall are substantially open to avoid the trapping of heat. The at least one component is substantially thermally shielded by the enclosing side walls and ceiling from engine generated heat. 
     In a further aspect of the disclosure, at least two enclosing side panels of the cooling module define left and right module walls that include hydraulic oil passages. In this additional aspect, the at least one component is substantially thermally protected from engine generated heat via both active cooling of, and passive heat radiation from, the cooling module. 
     In yet another aspect of the disclosure, a method of making a cooling module includes providing a plurality of thermally conductive panels configured to include a plurality of tubular coolant passages, and joining the panels together to form an enclosure defined by interior surfaces of the panels. The panels define individual walls and a ceiling, and include a substantially open floor and at least one substantially open side wall. At least one engine component is substantially thermally shielded by the cooling module from engine generated heat. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a rear to front perspective view of a portion of an upper surface of an engine, depicting the environment of a prior art EGR venturi, shown supported by a bracket, and including a view of the venturi inlet connected to three EGR coolers via a converging manifold. 
         FIG. 2  is also a rear to front perspective view of an upper surface portion of an engine similar to that shown in  FIG. 1 , but without the bracket, and providing a fragmentary view of the disclosed cooling module (depicted only partially above the venturi), shown secured to an engine manifold and adapted to support the venturi on a pair of spaced legs. 
         FIG. 3  is a cross-sectional view of the entire cooling module and the venturi, as would be viewed along lines  3 - 3  of  FIG. 2 . 
         FIG. 4  is an enlarged perspective view of the cooling module of  FIG. 3 , with an upper portion of the cooling module removed to permit a view along lines  4 - 4  of  FIG. 3  to reveal cooling passages within the module walls and floor portion. 
         FIG. 5  is a perspective view of the entire cooling module of  FIG. 3 . 
         FIG. 6  is a similar perspective view of the entire cooling module, but depicted as a standalone unit just prior to installation, without the engine connections of  FIG. 5 , and with the support legs of the module disconnected from the engine manifold. 
     
    
    
     DETAILED DESCRIPTION 
     Referring initially to  FIG. 1 , an upper surface of an engine  10  includes an EGR valve  12 , along with an absolute pressure sensor  14  and a differential or so-called Delta pressure sensor  16 . Each of the sensors  14 ,  16  may have associated wiring and/or wiring harnesses  18 . An EGR venturi  20  is generally associated with considerable heat output due to the high temperature exhaust gases flowing therethrough. The heat output of the EGR venturi  20  is known to be potentially deleterious to electronic components and associated wiring, including harnesses, attached thereto. A venturi inlet  22  may be adapted to receive high-pressure exhaust gases through a venturi header  24 , also variously called a splitter, which may receive gases from a plurality of EGR coolers  26  (three are shown fragmentarily) situated upstream of the venturi  20 . 
     A cooler-to-venturi coupling  28  assures airtight EGR gas flows into the venturi  20  from the coolers  26 . A prior art bracket  30  has typically been employed to support the venturi  20 , the bracket  30  being anchored to, and supported by, an air intake manifold (not shown). A thermal shield  40  has been used traditionally to attenuate and/or mitigate radiant engine heat, as is well known by those skilled in the art. However, the thermal shield  40  may insufficiently shield the electronic components and associated wiring attached thereto. 
     Referring now to  FIG. 2 , an exemplary embodiment of a cooling module of the present invention is disclosed. Thus, as shown in  FIG. 2 , an upper surface of an engine  110  may also support an EGR valve assembly  112  along with an absolute pressure sensor  114 , and a Delta pressure sensor  116 . Associated wiring and/or wiring harnesses  118  may be connected to the sensors  114 ,  116 . The sensors may be adapted to electronically monitor the rate of EGR gas flow through the venturi  120 . The venturi  120  may include a venturi inlet  122 , which inputs from a splitter  124 , situated downstream of three EGR coolers  126 . A cooler-to-venturi coupling  128  may be adapted to couple the splitter  124  to the venturi inlet  122  in a gas tight manner to facilitate high pressure EGR gas flows into the venturi  120 . Finally, a thermal shield  140  may be employed to mitigate transfer of radiant heat from the engine surface to electronic components and engine control devices situated above the engine  110 . 
     In lieu of the bracket  30  illustrated in  FIG. 1 , however, a cooling module  130  (shown only fragmentarily), also variously referred to as a chiller by those skilled in the art, may be employed to both support the physical venturi  120 , as well as to provide both active, including conductive and convective, as well as passive, i.e., radiative, cooling capabilities to avoid exposing the electronic components, such as the pressure sensors  114  and  116  and the EGR valve assembly  112  that may be situated above the engine  110 , to high heat loads. 
     Referring now also to  FIG. 3 , in addition to the above-described inlet  122 , situated at the front of the cooling module  130 , the venturi  120  has an outlet  132 . From the outlet  132 , EGR gases flow into a venturi outlet conduit  134  and ultimately back into an intake manifold (not shown). In  FIG. 3 , more of the thermal shield  140  is shown as it extends immediately above the engine  110  and below the venturi  120 . 
     Positioned above the venturi  120 , the disclosed cooling module  130  is shown in cross-section. The cooling module  130  has the form of a multi-paneled enclosure, generally defining substantially enclosed sides and a top, but having its front side and its bottom being substantially open. The panels  136  are shown generally in  FIG. 3  as the top and sides of the cooling module  130 . Immediately above the venturi  120  is positioned a sensor mounting block  142  in which sensing passages  115  and  117 , respectively, are drilled to permit EGR gas pressures to be transmitted to pressure sensors  114  and  116 . In the described configuration, the mounting block  142  is a physical part of the venturi casting, although this disclosure is not limited to such a construction. In  FIG. 3 , the sensors  114  and  116  are shown to be secured directly to the mounting block  142 . 
     The mounting block  142  may be positioned to support the sensors  114 ,  116  inside of the enclosure panels  136  (e.g.  180  and  190 ) of the cooling module  130 . Water coolant passages  150  and  152  (shown in cross-section only) may run through the upper portion of the mounting block  142 , i.e., just below the pressure sensors  114 ,  116 , to enhance cooling effect for protection of the sensors  114 ,  116 . Mounted to the venturi outlet  132  and positioned forwardly of the mounting block  142 , the EGR valve assembly  112  may also be supported within the paneled enclosure of the cooling module  130 . Thus, the EGR valve assembly  112  and its associated electro-hydraulic actuator  220  may be supported, so as to extend through the substantially open front wall  210  of the cooling module  130 . Extending laterally through a floor portion  148  of the cooling module  130  may be a coolant water passage  154 , strategically positioned below the EGR valve assembly  112  to effectively cool the valve assembly  112 . 
     Referring now also to  FIGS. 4 and 5 , a pair of left and right cooling module support legs  160 ,  162  may be offset from the cooling module  130 , as shown. The legs  160 ,  162  may include pairs of structural connectors  164 ,  166 , respectively, to accommodate routing of wiring harnesses  118 , as particularly shown in  FIG. 5 . Also, shown in  FIG. 5 , at least one coolant coupling connector  170  and at least one coolant line  174 ,  182  may be positioned to accommodate flows of coolant into each of the right and left sidewalls  172  and  180  of the cooling module  130 . For this purpose, the walls  172  and  180  may be formed of a material having a relatively high heat transfer coefficient, such as an aluminum metal alloy to facilitate expeditious transfer of passive or radiant heat loads. The walls  172 ,  180  may contain integral interior coolant passages (not shown) for providing active cooling. Such interior wall coolant passages may be formed into the walls by an aluminum casting process, as may be appreciated by those skilled in the art. 
     Referring now specifically to  FIG. 4 , a perspective view of the laterally extending water coolant passage  154  more clearly reveals that the passage  154  passes through the floor portion  148 , and runs between the left and right walls  180 ,  172 , respectively, of the cooling module  130 . 
     Referring now also to  FIG. 6 , the multi-paneled cooling module  130  has its several panels  136  joined together to form right and left sidewalls  172 ,  180 , respectively, and a rear wall  190 . It will be appreciated that the sidewalls  172 ,  180 , the rear wall  190 , and the top wall or lid  198  may be joined together to form a paneled enclosure adapted to substantially protect enclosed electrical components, including the described EGR valve assembly  112 , pressure sensors  116 ,  116 , and associated wiring harnesses  118 , from heat damage, particularly when active cooling is provided by integral coolant passages strategically incorporated to accommodate coolant flows within the described panels  136 . 
     As may best be seen in  FIGS. 4 and 6 , a multiplex conduit  176  may be integrated into the right wall  172  as shown for accommodating cooling of hydraulic passages  178  that extend to an electro-hydraulic EGR valve actuator  220 . For such purpose, the coolant line  174  runs parallel and proximally to the pair of hydraulic passages  178  ( FIG. 4 ) within the same panel  136  (e.g., right wall  172  as shown). The EGR valve actuator  220  may alternatively be completely electronically actuated, in which case the hydraulic multiplex conduit  176  could be modified and/or adapted to cool an electric harness instead. 
     As described, such multiplex conduit may be cast into the aluminum panels  136  (e.g., right wall  172 , as shown) with integral passages machined into the cast panels. Other materials, besides aluminum, may be utilized for actual fabrication of the panels  136 . In addition, other means may be employed to form or incorporate the described conduit features into the panels, such as, by way of example, inserts that may be cast into the panels to avoid subsequent machining operations, such as drilling. 
     For accommodating the offset support legs  160 ,  162  of the cooling module  130 , an extension bracket  184 ,  186  may be formed as integral extensions of each of the right and left walls  172 ,  180 , respectively. The result is a cooling module  130  that may be effectively cantilevered over the EGR venturi  120  by the support legs  160 ,  162 , as best depicted in  FIG. 3 . Bolts  188  may be vertically inserted through the support legs  160 ,  162  to secure the legs to an intake manifold. Alternatively, other means, for example welding, may be employed for securement of the legs  160 ,  162  to the manifold. 
     The rear wall  190  ( FIG. 3 ) may be vertically split as shown in  FIG. 6  into left and right halves  192 ,  194 , respectively, thus defining a vertical joint line  196  of a resultant bifurcated rear wall  190 . Having the cooling module  130  split into left and right halves may better facilitate its installation over the above-described electronic components. The lid  198  may be adapted to secure the left and right halves together by bolts  200  ( FIGS. 5 and 6 ). Although the cooling module  130  is depicted herein as being split into left and right halves in a rear-to-front orientation, other embodiments are envisioned herein, including a laterally oriented split, for example, with the split extending medially through the centers of right wall  172  and left walls  180 . 
     The lid  198  may be spaced approximately 4 to 10 mm above the sidewalls  172 ,  180  and rear wall  190  to avoid trapping heated air. As best seen in  FIG. 3 , mounting bosses  202  at the bottom of the lid  198  at each bolt  200  may be configured to provide an air gap  204  under the lid  198  which may, along with the open front wall  210 , facilitate movement of ambient air for convective transfer of heat from within the module panels  136 . 
     Finally, the disclosure of the cooling module  130  has contained only descriptions of the panels  136  as separately formed. However, the cooling module  130  may be envisioned in alternative embodiments, for example, formed with all panels  136  as a one-piece structure. Such a one-piece cooling module  130  could be formed by casting, stamping, or via other means, all within the scope of this disclosure. 
     INDUSTRIAL APPLICABILITY 
     The disclosed cooling module  130  may provide protection of electronic components from damage resulting from engine heat in a variety of machines, including milling machines, excavation machines, haulers, and electric power generators, among many others. 
     The disclosed cooling module  130  may have a generally box-shaped structure as shown and described, including the generally flat panels  136 , as also described herein. Alternatively, however, the module  130  may be configured to have other shapes, with the panels having other shapes, such as curved, hexagonal, etc., and yet fall within the scope of this disclosure. 
     The various walls of the cooling module  130 , including the right wall  172 , left wall  180 , rear wall  190 , top wall or lid  198 , and front wall  210 , cooperatively work together to keep radiative heat out of the interior of the cooling module  130 . On the other hand, conductive heat loads are passed directly from the walls into the integral coolant water passages, including coolant water passage  150 ,  152 , and  154  to be carried away from the cooling module  130 . Finally, convective heat loads are adapted to be moved away from the cooling module  130  via the air gap  202  under the top wall or lid  198  as described, as well as via the open front wall  210 . 
     In operation, the cooling module  130  may be effective to reduce temperatures of engine mounted electronic components even when subjected to engine heat loads exceeding 700° F. Ambient air will generally rise from engine and thermal shield areas. As the air passes through and within the cooling module  130 , the air will carry away heat convectively from the panels  136 . The as-described coolant water will pass through the panels  136  to conductively carry away heat, while the temperature differential between the panel walls and the ambient air will generate radiative heat transfers away from the module  130 . 
     A method of cooling an electronic module situated above an EGR venturi by forming an exterior engine-mounted cooling module  130  may include providing a plurality of thermally conductive panels, and joining the panels together to form an enclosure defined by cooled interior surfaces of the panels for providing active cooling by conduction of heat away from the interior of the module. As such, the panels may define individual walls and a ceiling. 
     The method may further include providing a substantially open floor and at least one substantially open front wall for providing convective movement of heat out of the interior of the module, and configuring the cooling module to include a plurality of integral coolant passages strategically arranged to pass through the panels, both within the side walls and the floor of the module. Such cooling module structure may also be adapted to thermally shield at least one engine component from a radiative heat generating engine device and/or from conductive, convective, and radiative engine generated heat loads.