Patent Publication Number: US-2019170057-A1

Title: Charge air cooler (cac) having a condensate dispersion device and a method of dispersing condensate from a cac

Description:
INTRODUCTION 
     The present disclosure relates to a vehicle heat exchanger, more particularly to a charge air cooler. 
     Modern high efficiency engines utilizes compressors, such as supercharges and turbocharges, to increase the power of an internal combustion engines during periods of high output power demands, such as accelerating from a stop light or margining onto a highway. The compressors increase the density of air, enabling the combustion process to burn more fuel per cycle, thus increasing power output. 
     The temperature of the compressed air is significantly higher than the ambient inlet air due to the compression process. Charge-air coolers (CAC) are employed to remove excessive heat from the compressed air prior to the inlet of the combustion chamber of the internal combustion engine to enhance combustion efficiency, resulting in improved fuel economy and fewer undesirable emissions. CAC are typically air-to-air heat exchangers where heat from the higher temperature compressed combustion air flowing through the CAC is transferred to the external cooler ambient air, resulting in a reduction in temperature of the combustion air. 
     During periods of low power demand, such as idling or normal cruising conditions, when the intake air is not as highly compressed as when there is a high power demand, the effectiveness of the CAC can cause the internal airflow through the CAC to experience a transition in temperature to fall below the dew point temperature, thereby causing moisture in the intake air to condense forming water condensate within the CAC. A sufficient volume of condensate may accumulate within the CAC, thereby obstructing air flow through the CAC to the engine. As the pressure, temperature, and flow rate of combustion air through the CAC are increased due to high output demands, sufficient amounts of condensate may be evaporated and/or droplets of condensate may be dislodged into the combustion air flow. Unmetered water vapor and condensate droplets entering the combustion chamber of the engine may hinder the combustion process, thus resulting in undesirable engine performance. Furthermore, depending on the external ambient air temperature, the accumulated condensate within the CAC may freeze, thereby further obstructing combustion airflow through the CAC as well as potentially damaging the CAC. 
     Thus, while current CAC achieve their intended purpose, there is a need for a CAC having a new and improved condensate dispersion device, and a method for dispersing condensate from CAC. 
     SUMMARY 
     According to several aspects, a heat exchanger having a condensate dispersion device is disclosed. The heat exchanger includes an outlet housing having an interior surface defining an outlet airflow chamber, and an outlet port in fluid communication with the outlet airflow chamber; an outlet duct in fluid having an interior surface defining an outlet duct airflow passageway in fluid communication with the outlet port; and a wicking material having a first end and a second end opposite the first end. The first end is disposed in the outlet airflow chamber and the second end is disposed in the outlet duct airflow passageway. 
     In an additional aspect of the present disclosure, the interior surface of the outlet housing further defines a condensate receiver located at a lower portion of the outlet airflow chamber and the first end of the wicking material is disposed within the condensate receiver. 
     In another aspect of the present disclosure, the wicking material includes an elongated body extending from the first end through the outlet port to the second end. 
     In another aspect of the present disclosure, the heat exchanger further includes an airflow tube having an airflow tube outlet end in fluid communication with the outlet airflow chamber. A first portion of the elongated body of the wicking material is spaced from the airflow tube outlet end and abuts against a portion of the interior surface of the outlet housing such that the wicking material does not substantially obstruct an airflow through the outlet airflow chamber 
     In another aspect of the present disclosure, a second portion of the elongated body of the wicking material is abutted against a portion of the interior surface of the outlet duct such that the wicking material does not substantially obstruct the airflow through the outlet duct airflow passageway 
     In another aspect of the present disclosure, the heat exchanger further includes a plurality of fasteners fixing the first and second portions of the elongated body of the wicking material against the portion of the interior surface of the outlet housing and against the portion of the interior surface of the outlet duct, respectively. 
     In another aspect of the present disclosure, the wicking material comprises a rectangular cross-section. 
     In another aspect of the present disclosure, the wicking material includes a material configured to draw condensate and releases the drawn condensate into a stream of airflow by evaporation. 
     In another aspect of the present disclosure, the first end of the wicking material includes a first cross-sectional area and the elongated body includes a second cross-sectional area, in which the first cross-sectional area is greater than the second cross sectional area. 
     According to several aspects, a charge air cooler having a condensate dispersion device is disclosed. The CAC includes an inlet housing having an inlet port configured to receive a heated pressurized airflow containing a water vapor; an outlet housing having an outlet port and an interior surface defining a condensate receiver located at a lower portion of the outlet housing; a plurality of airflow tubes connecting the inlet housing to the outlet housing such that the inlet housing is in fluid communication with the outlet housing, in which the plurality of airflow tubes are configured transfer heat from the heated pressurized airflow to an ambient airflow; and a wicking material partially disposed in the condensate receiver and extending through the outlet port of the outlet housing. 
     In an additional aspect of the present disclosure, the CAC further includes an outlet duct having an inlet end engaged to the outlet port of the outlet housing and an outlet end opposite of the inlet end. The wicking material includes a first end, a second end opposite the first end, and an elongated body extending from the first end to the second end. The first end of the wicking material is disposed within the condensate receiver, the second end of the wicking material is disposed within the outlet duct, and the elongated body extends from the outlet housing into the outlet duct through the outlet port. 
     In another aspect of the present disclosure, the elongated body of the wicking material is abutted against a portion of the interior surface of the outlet housing and against a portion of an interior surface of the outlet duct such that the wicking material does not substantially obstruct the airflow through the outlet housing and outlet duct. 
     In another aspect of the present disclosure, the CAC further includes a plurality of fasteners fixing the elongated body of the wicking material against the respective portions of the interior surfaces of the outlet housing and of the outlet duct. 
     In another aspect of the present disclosure, the wicking material includes a rectangular cross-section. 
     In another aspect of the present disclosure, the wicking material includes a material configured to draw condensate from the condensate receiver and evaporate the drawn condensate into a stream of airflow through the outlet duct. 
     In another aspect of the present disclosure, the wicking material includes a braided strand material. 
     According to several aspects, a method of dispersing condensate from a charge air cooler is disclosed. The method includes the steps of cooling an airflow containing moisture below a dew point of the airflow such that a portion of the moisture condenses into droplets of liquid; passing the airflow through an outlet housing of the charge air cooler such that a portion of the droplets coalesces into a condensate and settles into a lower portion of the outlet housing; wetting a wicking material by contacting a first portion of the wicking material with the settled condensate such that the condensate wets a second portion of the wicking material extending from the first portion; and exposing the second portion of the wicking material to the airflow such that the condensate wetting the second portion evaporates into the airflow. 
     In an additional aspect of the present disclosure, the method further includes the step of fixing the second portion of the wicking material against an internal surface of the outlet housing such that the second portion of the wicking material does not substantially obstruct the airflow through the outlet housing. 
     In another aspect of the present disclosure, the method further includes the step of extending the second portion of the wicking material through an outlet port of the outlet housing into an outlet duct. 
     In another aspect of the present disclosure, the method further includes the steps collecting the settled condensate in a condensate receiver located at a lower portion of the outlet housing; and disposing the first portion of the wicking material in the condensate receiver such that the first portion of the wicking material is contact with the condensate. 
     Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
         FIG. 1  shows an air intake system, having a charge air cooler (CAC), for an internal combustion engine, according to an exemplary embodiment; 
         FIG. 2  shows a condensate wick disposed within an end housing of the CAC of  FIG. 1 , according to an exemplary embodiment; 
         FIG. 3A  shows the condensate wick of  FIG. 2 , according to an exemplary embodiment; and 
         FIG. 3B  shows the condensate wick of  FIG. 2 , according to another exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. 
       FIG. 1  shows an intake system  100  for delivering combustion air to an internal combustion engine (not shown). The combustion air is mixed with fuel to form an ignitable air/fuel mixture for a combustion process in the engine to generate power to propel a vehicle, such as an on-road vehicle, water vehicle, or air vehicle. The internal combustion engine may also be used as a power generating component on a hybrid vehicle to charge an electrical system or to assist in propelling the hybrid vehicle. 
     The intake system  100  includes an ambient air inlet  102 , an air filter assembly  104 , an air compressor  106 , and a charge air cooler (CAC)  108 . Ambient air is collected through the ambient air inlet  102  and conveyed to the air filter assembly  104  through an air intake duct  110 . The air filter assembly  104  contains a filter media (not shown) that removes particular matter from the airflow that may damage the intake system  100  and/or the engine. The filtered airflow exits the air filter assembly  104  and is directed to the compressor  106  through a compressor inlet duct  112 . The compressor  106  selectively compresses the volume of airflow, thereby increasing the pressure and temperature of the airflow above the pressure and temperature of the ambient air. 
     The compressed airflow exiting the compressor  106  is routed through a CAC inlet duct  113  to the CAC  108 . Heat is removed from the compressed airflow by the CAC  108  to reduce the temperature of the compressed airflow. The cooled compressed air flow exits the CAC  108  through the CAC outlet duct  114  to the engine intake manifold  116  and to the engine combustion chambers (not shown). Fuel may be introduced into the cooled compressed airflow immediately prior to the combustion chambers or within the combustion chambers. 
     The compressor  106  compresses the volume of filtered air flow to increase the density of the airflow, thereby providing more oxygen per unit volume of airflow to the engine for more efficient combustion of fuel to increased power output. The compressor  106  may be that of a supercharger or a turbocharger type compressor. Supercharger type compressors are typically powered by a mechanical power-takeoff, such as a belt, gear, and/or shaft, from a crankshaft of the engine. Modern supercharger type compressors are powered by an electrical motor to avoid direct power draw from the engine. Turbocharger type compressors are powered by the hot exhaust gases of the engine, in which the hot exhaust gases turn a turbine that compresses the filtered airflow. 
     The compressors  106  selectively increase the density of the combustion airflow depending on the demand for output power from the engine. The greater the density of the combustion air supplied to the engine, the greater the output power that the engine can generate. Also, the greater the density, the greater amount of heat is generated during the compression process. Turbocharger type compressors generate greater amounts of heat than supercharger type compressors due to the heat transferred from the hot exhaust gases conducted through the metallic housing and turbine of the turbocharger type compressor to the airflow that is being compressed. Exemplary temperatures of the compressed airflow exiting a turbocharger type compressor can be as high as 200° C. 
     The compressed airflow exiting the compressor  106  is routed through the CAC  108  to reduce the temperature of the compressed airflow before being routed to the engine. The exemplary CAC  108  includes an inlet housing  118  having an air inlet port  120  and an air outlet housing  122  having an air outlet port  124 . A plurality airflow tubes  126  fluidically connect the inlet housing  118  to the outlet housing  122 . At least one of the plurality of tubes  126  include an inlet end  128  in fluid connection with the inlet housing  118  and an opposite outlet end  130  in fluid connection with the outlet housing  122 . The plurality of airflow tubes  126  extends parallel with each other from the inlet housing  118  to the outlet housing  122 . 
     The CAC  108  also includes a plurality of corrugated fins  132  interconnecting the external surfaces of adjacent fluid tubes  126  to increase the external surface area of the CAC  108  for increased heat transfer efficiency. The plurality of airflow tubes  126  and the plurality of corrugated fins  132  defines a CAC core  134  sandwiched between the inlet housing  118  and outlet housing  122 . The corrugated fins  132  interconnecting adjacent airflow tubes  126  defines a plurality of external airflow passageways  136 . The airflow passageways  136  provides for ambient airflow through the core  134  perpendicular to the compressed airflow through the airflow tubes  126 . While a corrugated type fin is shown, it should be appreciated that other types of air-side fins  132 , such as plate fins, may be utilized to increase the external heat transfer area of the CAC  108 . 
       FIG. 2  shows a partial cut-away view of the outlet housing  122  of the CAC  108  and an outlet duct  114  extending from the outlet housing  122 , as generally indicated with reference numeral  2  in  FIG. 1 . The outlet housing  122  includes an interior surface  138  defining an outlet airflow chamber, generally indicated with reference number  140 , having a condensate receiver  142 . The outlet duct  114  includes an interior surface  143  defining an outlet duct airflow passageway  145 . It is preferable that the condensate receiver  142  is located at a lower portion of the outlet airflow chamber  140  where liquid condensate would settle under the force of gravity. A condensate wicking material  144  is shown partially disposed within the outlet airflow chamber  140  of the CAC  108  and extending into the CAC outlet duct  114  toward the engine intake manifold  116 . A first portion of the wicking material  144  is located within the outlet housing  122  and a second portion is located within the outlet duct  114 . A segment of the first portion of the wicking material  144  is disposed within the lower portion of the chamber  140  such that any condensate settled within the condensate receiver would come in physical contact with the wicking material  144 . 
     Shown in  FIG. 3A  and  FIG. 3B  are exemplary condensate wicking material  144  having a first end  146 , a second end  148  opposite of the first end  146 , and an elongated body  150  extending therebetween. The condensate wicking material  144  may be any material that is capable of drawing, or wicking, condensate and allowing the wicked condensate to evaporate into an airflow upon contact with the airflow. Examples of wicking materials includes, but are not limited to, hydrophilic materials, absorbent materials such as sponges, adsorbent materials such as activated carbon, and materials having multiple strands capable of inducing capillary action. 
     In the embodiment shown in  FIG. 3B , the first end  146  of the wicking material  144  includes a first cross-sectional area  152  and the elongated body  150  includes a second cross-sectional area  154 . The first cross-sectional  152  area is larger than the cross-sectional area  154  of the elongated body  150 . The larger cross sectional area of the first end  146  provides greater contact area with the condensate settled within the condensate receiver  142 . The first end  146  may include a first wicking material and the elongated body  150  may include a second wicking material. In one embodiment, the first and second wicking material are the same material. In another embodiment, the first and second wicking material are different materials. 
     The elongated body  150  may be abutted against the interior surface  138  of the outlet housing  122  and fixed in position with adhesives or fasteners  156  to prevent the wicking material  144  from significantly obstructing airflow through the outlet housing  122  such that the combustion process is undesirably affected. The wicking material  144  may include any shaped cross-sectional area including a rectangle as shown in  FIG. 3A , a circle as shown in  FIG. 3B , or square. An advantage of a rectangular cross-sectional wicking material  144  is that the wider width W of the wicking material  144  may be fixed on the interior surfaces of the outlet housing  122  and/or outlet duct  114  to minimize the protrusion of the wicking material  144  into the airflow, thereby minimizing any disturbance of airflow to the engine. 
     The CAC core  134  is configured to provide sufficient cooling of the high temperature compressed airflow from the compressor  106  during periods of high power output demand from engine. However, during periods of nominal or low power output demand from the engine, the compressor  106  is not compressing the combustion air to a pressure and temperature as high as during periods of high power output demand. As the lower temperature compressed airflow passes through the airflow tubes  126 , the airflow tubes  126  provides sufficient cooling such that the lower temperature compressed airflow may drop below its dew point. As the lower temperature compressed airflow drops below its dew point, the moisture in the compressed air condenses into liquid particles and droplets, resulting in a dehumidified airflow. The momentum of the compressed airflow through the airflow tubes  126  carries the liquid particles and droplets to the outlet housing  122  of the CAC  108 . As droplets of condensate collides and coalesces with other droplets, the liquid condensate drops out and settles in the outlet housing  122 . 
     The liquid condensate settles in the lower portion of the outlet housing  122 , in which the first end  146  of the wicking material  144  is disposed. The liquid condensate comes in contact with the first end  146  of wicking material  144  and, by way of capillary action, the wicking material  144  draws the liquid condensate through the elongated body  150  of the wicking material  144 . Depending on the amount of condensate formed in the outlet housing  122 , the condensate is drawn from the first end  146  of the wicking material  144  through the elongated body  150  of the wicking material  144  to the second end  148  of the wicking material  144 . 
     As the dehumidified airflow exits the outlet port  124  of the outlet housing  122  and flowing through the outlet duct  114  to engine manifold  116 , the dehumidified air flow comes in contact with the elongated body  150  and second end  148  of the wicking material  144 . The lower humidity airflow causes the moisture in the wicking material  144  to evaporate into the combustion airflow and into the combustion chamber. The overall length of the wicking material  144  extending into the outlet duct  114  toward the engine may be adjusted accordingly to metered predetermined amounts of condensate evaporating into the airflow to the engine during periods of high power output demand. 
     It should be appreciated that the wicking material  144 , in essences, controls the rate of condensate removal from the outlet housing  122  by evaporating the condensate back into the combustion airflow in a metered fashion. Without the wicking material  144  metering the rate of condensate removal from the outlet housing  122 , the amount of condensate accumulated in the outlet housing  122  may cause droplets or slugs of condensate to splash out of the outlet housing  122  into the airflow towards the engine. The momentum of the airflow would carry the droplets or slugs of condensate to the combustion chamber, thereby causing combustion issues resulting in poor engine performance and the engine management controller generating error codes. 
     While the invention has been described with reference to exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed, but that the invention will include all embodiments falling within the scope of the application.