Patent Publication Number: US-7588018-B2

Title: Exhaust gas recirculation cooler bypass cartridge

Description:
This application claims the benefit of the earlier filing date of U.S. Provisional Application No. 60/811,285, filed on Jun. 6, 2006, which is incorporated by reference herein in its entirety. 

   FIELD OF THE INVENTION 
   The present invention relates to a cooler for use in an exhaust gas recirculation (EGR) system in an internal combustion engine and, more particularly to a bypass valve cartridge provided in the cooler. 
   BACKGROUND OF THE INVENTION 
   In general, when diesel fuel is burned in an engine, nitrogen oxides are produced in the exhaust gas. An EGR cooler provides a cooled dilutent to lower combustion temperatures and reduce the concentration of nitrogen oxides in the exhaust gases. Typically, when an engine is first started, a bypass valve, separate from the EGR cooler, is used to bypass the EGR cooler and redirect uncooled gasses through the engine to accelerate engine warmup. These bypass valves must withstand high temperature and are typically complicated, with an expensive, machined housing. 
   There is a need to provide an inexpensive and replaceable bypass valve for a EGR cooler. 
   SUMMARY OF THE INVENTION 
   An object of the invention is to fulfill the need referred to above. In accordance with the principles of the present invention a bypass valve cartridge is provided for permitting exhaust gas recirculation (EGR) flow to bypass a cooler port of a cooler of a vehicle. The cartridge includes housing structure constructed and arranged to be inserted into and mounted in a portion of a cooler. Flapper structure is disposed in the housing structure and is movable between a first position permitting EGR flow to pass to the cooler port and a second position substantially preventing EGR flow to pass to the cooler port. 
   In accordance with another aspect of the invention, a bypass valve cartridge and cooler combination includes a bypass valve cartridge having housing structure and flapper structure disposed in the housing structure and movable between first and second positions. The cooler cools exhaust gas recirculation (EGR) flow and includes surfaces defining an opening leading to an internal space in the cooler. The cooler has internal walls near the opening and in the internal space. The cartridge is removably disposed in the internal space of the cooler with the housing structure being coupled with certain internal walls so that an inlet port, a cooler flow port, and a bypass flow port are defined in the internal space. When the flapper structure is in the first position, EGR flow is permitted to pass from the inlet port to the cooler port, and when the flapper structure is in the second position, EGR flow is permitted to pass from the inlet port to the bypass flow port while being substantially prevented from passing to the cooler port. 
   In accordance with yet another aspect of the invention, a method provides a bypass valve cartridge in a cooler of a vehicle. A cooler is provided for cooling exhaust gas recirculation (EGR) flow. The cooler has surfaces defining an opening leading to an internal space in the cooler. The cooler has internal walls near the opening and in the internal space. A bypass valve cartridge has housing structure and flapper structure disposed in the housing structure and movable between first and second positions. The cartridge is inserted through the opening and into the internal space, with the housing structure being coupled with certain internal walls so that an inlet port, a cooler flow port, and a bypass flow port are defined in the internal space and so that movement of the flapper structure between the first and second positions controls the EGR flow from the inlet port through either the cooler flow port or the bypass flow port. 
   Other objects, features and characteristics of the present invention, as well as the methods of operation and the functions of the related elements of the structure, the combination of parts and economics of manufacture will become more apparent upon consideration of the following detailed description and appended claims with reference to the accompanying drawings, all of which form a part of this specification. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be better understood from the following detailed description of the preferred embodiments thereof, taken in conjunction with the accompanying drawings, wherein like reference numerals refer to like parts, in which: 
       FIG. 1  is a front view of an EGR cooler bypass valve cartridge in accordance with an embodiment of the invention. 
       FIG. 2  is a view of the bypass valve cartridge of  FIG. 1  shown mounted with respect to walls of a cooler. 
       FIG. 3  is a partial sectional view of the cartridge taken along the line  3 - 3  in  FIG. 2 , showing flap structure in a cooling flow mode position. 
       FIG. 4  is a sectional view of the cartridge showing the flap structure in a bypass flow mode position. 
       FIG. 5  is a view of a cooler having the cartridge of  FIG. 1  installed therein. 
       FIG. 6  is a sectional view of another embodiment of the flapper structure of the cartridge. 
   

   DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS 
   With reference to  FIGS. 1-3 , an EGR cooler bypass valve cartridge is shown, generally indicated at  10 , in accordance with an embodiment of the invention. The cartridge  10  includes a housing structure, generally indicated at  11 . In the embodiment, the housing structure  11  includes a pair of housings  12 ,  12 ′ disposed in spaced relation. As shown in  FIG. 1 , a first end  14  of housing  12 ,  12 ′ is coupled with a first end cap  16  and a second end  18  of housing  12 ,  12 ′ is coupled with a second end cap  20 . The end caps  16  and  20  can be considered to be part of the housing structure  11 . 
   The cartridge  10  also includes a flap structure  22  mounted for rotation between first and second positions, as will be explained more fully below. More particularly, the flap structure  22  is generally a flat plate structure that is supported by a bearing structure  23  at each end thereof. The flap structure  22  is coupled with a shaft  24  at one end thereof such that rotation of the shaft  24  rotates the flap structure  22 . The housings  12 ,  12 ′ and flap structure  22  are preferably stamped parts and the end caps  16 ,  20  are preferably made of sintered powdered metal. Thus, no complicated and expensive machining is required. 
   With reference to  FIGS. 2 and 3 , each housing  12 ,  12 ′ has a pair of longitudinally extending grooves  26  therein that receive internal walls  27  of a cooler. More particularly, with reference to  FIG. 5 , the cartridge  10  is received in an opening  28  leading to an internal space  29  ( FIG. 2 ) in an EGR cooler  30 . The internal walls  27  near the opening  28  are received in the grooves  26 . The cartridge  10  is disposed in the opening  28  in a position that separates flow passages for cooled and un-cooled EGR flow. To reduce leakage, the cartridge  10  enters the cooler  30  from one side only and is held in place with a cover plate (not shown) and a gasket (not shown). 
   With reference to  FIGS. 2 and 3 , when the cartridge  10  is provided in the cooler  30 , the internal walls  27  and cartridge  10  define an inlet port  32 , a cooler port  34 , and a bypass port  36  in the internal space  29 . When the flap structure  22  is in the first position ( FIG. 3 ) the cartridge  10  is in a cooling flow mode position where EGR flow (indicated by arrow A) is permitted to pass from the inlet port  32  to the cooler port  34  and be cooled by the cooler  30 . 
   When the flap structure  22  is in the second position ( FIG. 4 ) the cartridge  10  is in a bypass flow mode position where EGR flow (indicated by arrow B) is permitted to pass from the inlet port  32  to the bypass flow port  36  and bypass the cooler flow port  34  so that the high temperature bypass flow is sent to the intake manifold (not shown) of a vehicle. In particular, in the bypass flow mode position, EGR flow is substantially prevented from entering the cooler flow port  34 . 
   The position of the flapper structure  22  is controlled by movement of the shaft  24  that is coupled to a motor (not shown). The motor can be controlled by an engine control unit. 
     FIG. 6  shows another embodiment of the flapper structure  22 ′. Instead of the flapper structure  22  being within the bounds of the housings  12 ,  12 ′, the flapper structure  22 ′ can extend outside the bounds of the housings  12 ,  12 ′. 
   Thus, by using the replaceable cartridge  10 , a defective cartridge can simply be removed and replaced. Further, since the cartridge  10  is not machined, the cost of an EGR bypass valve is reduced. 
   The foregoing preferred embodiments have been shown and described for the purposes of illustrating the structural and functional principles of the present invention, as well as illustrating the methods of employing the preferred embodiments and are subject to change without departing from such principles. Therefore, this invention includes all modifications encompassed within the spirit of the following claims.