Abstract:
A drop-in cartridge style, four-chamber EGR valve, includes a valve actuator, a valve stem extending from the valve actuator and having two valve heads mutually spaced on the stem, and a frame having a plurality of longitudinally extending members connected by at least first and second ring members, the frame being divided along a longitudinal axis into two mating parts.

Description:
FIELD OF THE INVENTION 
       [0001]    The invention relates to valve assemblies for exhaust gas recirculation, and more particularly, to a valve assembly that can be easily assembled and installed in an exhaust gas recirculation system. 
       BACKGROUND AND SUMMARY 
       [0002]    Exhaust gas recirculation EGR systems in internal combustion engines are controlled or metered by an EGR valve. The EGR valve meters the amount of EGR that will be introduced into the engine. The inlet flows and outlet flow are controlled by an EGR valve. 
         [0003]    As shown in  FIG. 1 , cartridge-style EGR valves  10  typically include an actuator  12  and a valve stem  14  having two valve heads  16 ,  18 . As shown in  FIG. 1 , the valve device  10  is placed in a valve housing  20  in the exhaust manifold or EGR valve body of an engine, which must have valve seats  22  machined or inserted therein. The valve heads  16 ,  18  are shown in the open position. This arrangement allows for three chamber EGR metering; the valve can control two inlet passages  24 ,  26  which join to form a single outlet passage  28 . This does not permit full use of the pressure pulses in the exhaust flow by the turbocharger system or the EGR system. 
         [0004]    The invention provides a solution in a drop-in cartridge style, four-chamber EGR valve. 
         [0005]    According to the invention, the cartridge valve includes a valve actuator, a valve stem extending from the valve actuator and having two valve heads mutually spaced on the stem, and a cage or frame having a plurality of axially extending bars connected by first and second ring assemblies, the ring assemblies being circumferential members. 
         [0006]    According to the invention, the cage is divided along a longitudinal axis into two mating parts. The division of the cage longitudinally provides a “clam shell” configuration that allows for simple assembly of the valve device. The mating parts of the cage allow the valve stem to be installed in the valve actuator and the cage assembled around the valve stem and valve heads in a simple manner. 
         [0007]    According to the invention, the first and second ring assemblies each have formed thereon a valve seat for one of the valve heads. Thus, the requirement of machining or forming the valve seats in the valve housing is eliminated. 
         [0008]    According to the invention, the cage may include a third ring assembly connecting the axially extending bars and disposed between the two ring assemblies with a sealing disk mounted to the third ring assembly to divide the cage axially. The sealing disk may be formed in two parts, one part being attached to each mating part of the cage, wherein, upon mating of the mating parts, the two parts of the sealing plate are joined as an integral disk. 
         [0009]    According to the invention, the ring assemblies may include seats for accepting an o-ring, the seats being formed on a radially outer surface of each ring assembly. The assembly may further comprise an o-ring mounted in each of the seats. The o-rings are configured to contact the inner walls of valve housing formed in the exhaust manifold or EGR valve body and thus provide seals in the valve housing to seal the four chambers from one another. 
         [0010]    Additional ring assemblies or circumferential members may be provided for structural support or for seating and sealing the frame in the valve housing. 
         [0011]    According to the invention, the cage may include four ring assemblies, an end ring assembly providing structural rigidity to the cage. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    The invention will be better understood by reference to the following detailed description read in conjunction with the appended drawings, in which: 
           [0013]      FIG. 1  is a sectional view of a valve assembly and a three-chamber EGR valve according to the prior art; 
           [0014]      FIG. 2  is a sectional view of a valve assembly of the invention and a four-chamber EGR valve; 
           [0015]      FIG. 3  is a side view of valve assembly in accordance with the invention; 
           [0016]      FIG. 4  is a sealing disk that may be installed in the assembly; and, 
           [0017]      FIG. 5  is an exploded view of the valve assembly of  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION 
       [0018]      FIG. 2  shows an EGR valve assembly  100  installed in a four-chamber EGR valve  50  in accord with the invention.  FIG. 3  shows the assembly removed from the exhaust manifold or EGR valve body. 
         [0019]    A valve housing  50  formed in an exhaust manifold or EGR valve body includes two inlet passages  52 ,  54  for recirculated exhaust gas and inlet air, and two outlet passages  56 ,  58 . As described below, the valve assembly  100  divides the valve housing  50  into four chambers  60 ,  61 ,  62 , and  63 . 
         [0020]    The valve assembly  100  includes a valve actuator  102 , a valve stem  104  operatively connected to and extending from the valve actuator, and two valve heads  106 ,  108  mounted in spaced relation on the valve stem. 
         [0021]    According to the invention, the assembly  100  includes a cage or frame  120  that surrounds the valve stem  104  and valve heads  106 ,  108 . The frame  120  is mounted to the valve actuator  102  by any convenient means. The frame  120  is formed by a plurality of longitudinal members  122  extending parallel or substantially parallel to the valve stem  104 . The longitudinal members  122  are interconnected by circumferential members  124 , spaced radially outward of the valve stem  104 . In the embodiment illustrated in  FIGS. 2 and 3 , five circumferential members,  124   a  to  124   e,  are shown; however, it may be possible to use fewer. 
         [0022]    The frame  120  includes at least two circumferential members that are formed with valve seats (identified as  124   b  and  124   d ) to cooperate with the valve heads  108  and  106 , respectively to close portions of the valve housing  50 . Referring now to  FIG. 2 , which shows the valve heads  106 ,  108  in an open position, when the valve stem  104  moves to the right in the figure, the valve head  108  contacts the valve seat formed on circumferential member  124   b  to close chamber  60  and prevent flow from inlet channel  52  from reaching chamber  61  and the outlet channel  56 . Similarly, valve head  106  contacts the valve seat formed on circumferential member  124   d  to close chamber  63  and prevent flow from inlet channel  54  from reaching chamber  62  and the outlet channel  58 . 
         [0023]    In the illustrated embodiment, a seal disk  130 , illustrated in  FIG. 4 , is provided in a circumferential member  124   c  to separate and seal chamber  61  from chamber  62 . With a seal disk  130  in the frame  120 , two flow paths are defined, one including inlet passage  52 , chambers  60  and  61  and outlet passage  56 , and a second including inlet passage  54 , chambers  62  and  63 , and outlet passage  58 . The disk  130  includes a centrally located hole  132  to accept the valve stem  104  and allow free movement therein. The seal disk  130  may be omitted depending on the desired flow pattern through the valve housing  50 . 
         [0024]    The frame  120  includes grooves  128  formed in radially outer surfaces of the longitudinal members  122  and circumferential members  124  to accept and retain o-rings  140  for sealing the frame in the valve housing  50 . Referring to  FIG. 2 , the o-rings  140  contact the valve housing walls to provide seals between the frame circumferential members  124  and the valve housing  50  walls so that the frame  120  helps define the plurality of chambers  60 ,  61 ,  62 , and  63 . 
         [0025]    Turning to  FIG. 5 , the frame  120  of the assembly is formed in two parts  120   a,    120   b,  divided longitudinally. Each part  120   a,    120   b,  will, with circular valve heads, be a half-cylinder and can be assembled around the valve stem  104  and valve heads  106 ,  108  in the manner of a clam shell. This facilitates assembly of the valve assembly. The parts  120   a  and  120   b  are joined at mating longitudinal members  123 ,  125  (longitudinal members on an opposite side of the parts, not visible in this view, will also mate). When a seal disk  130  is provided, the disk will be divided in two parts also, indicated by the line  134  in  FIG. 4 , with one disk part mounted in each of the two frame parts  120   a,    120   b.    
         [0026]    The invention has been described in terms of preferred principles, embodiments and components; however, those of skill in the art will understand that substitutions of equivalent components and structure may be made without departing from the scope of the invention as defined by the appended claims.