Abstract:
A cooler arrangement for connection to an exhaust gas manifold or to an exhaust gas outlet of an engine block of an internal combustion machine includes an exhaust gas cooler comprising at least one exhaust gas duct and a coolant jacket. The exhaust gas cooler is configured to be mounted at the engine block or at the exhaust gas manifold. An exhaust gas recirculation valve is configured to regulate an exhaust gas flow. An actuator is disposed on a side of the exhaust gas recirculation valve opposite the exhaust gas cooler. The actuator is configured to actuate the exhaust gas recirculation valve. A coolant duct segment is arranged between the exhaust gas manifold or the engine block and the actuator. The coolant duct segment is fluidically connected to the coolant jacket.

Description:
CROSS REFERENCE TO PRIOR APPLICATIONS 
       [0001]    This application is a U.S. National Phase application under 35 U.S.C. §371 of International Application No. PCT/EP2011/065050, filed on Aug. 31, 2011 and which claims benefit to German Patent Application No. 10 2010 045 259.9, filed on Sep. 14, 2010. The International Application was published in German on Mar. 22, 2012 as WO 2012/034866 A1 under PCT Article 21(2). 
     
    
     FIELD 
       [0002]    The present invention relates to a cooler arrangement for connection to an exhaust gas manifold or an exhaust gas outlet of an engine block of an internal combustion machine having an exhaust gas cooler with an exhaust gas duct and a coolant jacket mounted on the engine block or on the exhaust gas manifold, an exhaust gas recirculation valve by means of which the exhaust gas flow can be regulated, and an actuator by means of which the exhaust gas recirculation valve can be actuated, the actuator being disposed on the side of the exhaust gas recirculation valve opposite the exhaust gas cooler. 
       BACKGROUND 
       [0003]    For the sake of a simpler assembly and because of their reduced space requirements, exhaust gas cooler modules have been developed in increasing numbers in recent years, wherein an exhaust gas recirculation valve is arranged in a valve housing upstream or downstream of an exhaust gas cooler, the valve housing and the exhaust gas cooler forming a structural unit, by which they are jointly connected directly to the outlet portion of the engine block or of the exhaust gas manifold of the internal combustion engine in order to reduce the number of the conduits needed in the engine compartment. 
         [0004]    EP 1 643 097 A1 describes an exhaust gas cooler module wherein a heat exchanger housing is fastened to a flange plate through which the coolant ducts of the housing are connected with the coolant circuit of the internal combustion engine. A valve housing is fastened to the heat exchanger housing via a flange and extends into an exhaust gas inlet region of the heat exchanger that is arranged upstream of the actual cooling path but is nevertheless already formed with cooling ducts that surround the valve housing. This inlet region correspondingly serves to cool the valve body. There is a drawback, however, in that no thermal separation from the actuator is provided, while the housing thereof is still subjected to a high thermal load, especially due to heat radiation from the engine block. Since, however, very high temperatures of about 700° C. prevail at this site, there is a problem, especially when electric controllers are used, of excessive thermal load on the actuator, which may cause both inaccuracies in position control and a failure of the actuator and thus of the valve. 
         [0005]    Another cooler module is described in WO 2009/047278 A1 which also comprises an exhaust gas cooler as well as a bypass valve and an exhaust gas recirculation valve, which are connected with the housing of the exhaust gas cooler through a distributor housing. For the cooling of the exhaust gas recirculation valve, the distributor housing comprises coolant ducts. The actuator is arranged on a side of the module remote from the engine block so that a shielding is provided by the distributor housing. This embodiment, however, comes with an increased space requirement in the direction remote from the engine block. Modern internal combustion engines, however, often offer no additional space in that area. 
       SUMMARY 
       [0006]    An aspect of the present invention is to provide a cooler arrangement with which the functionality of the actuator can be provided over a long service life and wherein, at the same time, a minimum dimension to the side remote from the engine block is provided so that the cooler arrangement can be mounted at the engine block or at the exhaust gas manifold and in close proximity thereto, using the space available. 
         [0007]    In an embodiment, the present invention provides a cooler arrangement for connection to an exhaust gas manifold or to an exhaust gas outlet of an engine block of an internal combustion machine which includes an exhaust gas cooler comprising at least one exhaust gas duct and a coolant jacket. The exhaust gas cooler is configured to be mounted at the engine block or at the exhaust gas manifold. An exhaust gas recirculation valve is configured to regulate an exhaust gas flow. An actuator is disposed on a side of the exhaust gas recirculation valve opposite the exhaust gas cooler. The actuator is configured to actuate the exhaust gas recirculation valve. A coolant duct segment is arranged between the exhaust gas manifold or the engine block and the actuator. The coolant duct segment is fluidically connected to the coolant jacket. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    The present invention is described in greater detail below on the basis of embodiments and of the drawings in which: 
           [0009]      FIG. 1  shows a side elevational view of a detail of a cooler arrangement of the present invention, shown in section; and 
           [0010]      FIG. 2  shows a frontal view of the pre-cooler of the cooler arrangement of  FIG. 1 , shown as a top plan view. 
       
    
    
     DETAILED DESCRIPTION 
       [0011]    The fact that a coolant duct segment, which is in fluid communication with the coolant jacket of the exhaust gas cooler, is arranged between the exhaust gas manifold or the engine block and the actuator of the exhaust gas recirculation valve results in a thermal separation of the engine block or the exhaust gas manifold and the actuator. The actuator can thus be arranged in immediate proximity to the engine block. The assembly effort is not thereby increased. 
         [0012]    In an embodiment of the present invention, a pre-cooler can, for example, be arranged in the downstream direction of the exhaust gas between the exhaust gas cooler and the exhaust gas manifold or the engine block, whose pre-cooler housing has at least one coolant duct formed therein through which the coolant duct segment is connected with the coolant jacket of the exhaust gas cooler. It is thus achieved that the entire coolant supply is made directly to the coolant duct of a connected heat exchanger without having to use additional hose lines. An efficient cooling capacity exists at the same time in the region of the flap or flaps so that standard bearings, levers and springs can be used. Despite an assembly immediately at the exhaust gas manifold, this efficient cooling made directly at the origin of the heat allows the reduction of the load on all subsequent components. 
         [0013]    In an embodiment of the present invention, the coolant duct segment can, for example, be formed in the pre-cooler housing so that no additional components must be used to realize the thermal separation of the actuator. No hose lines are needed inside the module. 
         [0014]    In order to provide a flow in the coolant duct segment and to thereby increase the cooling effect, two coolant duct segments are provided between the engine block or the exhaust gas manifold and the actuator, which segments are in fluid communication via a connecting duct. The forward flow of the coolant occurs in the first of the two segments, while the return flow occurs in the second segment. 
         [0015]    In an embodiment of the present invention, at least one exhaust gas duct providing a deflection by 90° can, for example, be formed in the pre-cooler housing, and at least one coolant duct is respectively formed at two opposite sides of the at least one exhaust gas duct so that subsequent components, such as the heat exchanger, can be arranged parallel to the engine block, whereby the dimension of the cooler arrangement towards the side remote from the engine block is reduced to a minimum. At the same time, a reliable pre-cooling of the exhaust gas occurs immediately upon entry into the cooler arrangement. 
         [0016]    In an embodiment of the present invention, the at least one coolant duct extends in the pre-cooler housing from the coolant duct segment between the engine block or the exhaust gas manifold and the actuator along the 90° deflection in the pre-cooler housing to the coolant jacket at the side of the exhaust gas cooler remote from the exhaust gas manifold or the engine block. The inflowing exhaust gas is thereby reliably cooled in the pre-cooler over the entire inflow length. An additional thermal separation of the actuator towards the pre-cooler housing is also obtained, whereby the thermal load thereon is further reduced. 
         [0017]    For a further reduction of the assembly effort, the exhaust gas recirculation valve is a flap valve whose turning shaft is supported in the pre-cooler housing. The pre-cooler housing is at the same time the bearing housing of the flap, whereby additional mounting surfaces can be omitted. 
         [0018]    A cooler arrangement is thus provided that can be arranged entirely in immediate proximity to the exhaust gas manifold or to the engine block, without taking the risk of excessive thermal load on the actuator. Connection lines between the components can be omitted both for the coolant circuit and for exhaust gas guiding. The number of components is reduced to a minimum so that the assembly effort can be kept very low. The cooler arrangement can be fastened directly to the exhaust gas manifold or an exhaust gas outlet of an engine block. Due to the good cooling effect of this arrangement, less costly materials can be used, since the cooling efficiency of such an arrangement is increased when compared to known deigns. It is also conceivable to reduce the dimensions of the downstream cooler because of the good cooling effect of the pre-cooler. 
         [0019]    An embodiment of a cooler arrangement according to the present invention is illustrated in the Figures and will be hereinafter described. 
         [0020]    The detail of the cooler arrangement of the present invention illustrated in the Figures comprises a pre-cooler  2  with a pre-cooler housing  4 , as well as an exhaust gas recirculation valve  6  supported in the pre-cooler housing  4 , the exhaust gas recirculation valve  6  being formed by two flap elements  10  arranged on a common shaft  8  for rotation with the same, of which one flap element  10  is visible in the sectional view. The common shaft  8  is connected with an actuator  12  through a linkage. The actuator  12  can be an electromotive actuator. 
         [0021]    The pre-cooler housing  4  comprises a first flange  14  that serves as an exhaust gas inlet into the cooler arrangement and by which the pre-cooler housing  4  can be fastened directly to a non-illustrated engine block or exhaust gas manifold. This exhaust gas inlet is divided into two parts and leads to an exhaust gas duct  16  in the pre-cooler housing  4 , which duct is also divided into two parts, the flow sections thereof being adapted to be controlled by one of the flap elements  10 , respectively. 
         [0022]    An end of the common shaft  8  protrudes laterally from the pre-cooler housing  4 , as can be seen in  FIG. 2 . A first eccentric  18  is provided on this end for rotation with the same, the first eccentric  18  being coupled with a second eccentric  22  via a lever  20 , whereby the linkage is formed. The second eccentric  22  is arranged on a drive shaft  24  of the actuator  12  for rotation with the drive shaft  24 , so that a rotary movement of the actuator  12  is transmitted to the common shaft  8  of the exhaust gas recirculation valve  6 . 
         [0023]    The first eccentric  18  further has a stop element  26  formed thereon against which a first end leg  28  of a return spring  30  abuts that surrounds the common shaft  8 . This return spring  30  is designed as a helical spring that, in a manner known per se, biases the shaft  8  to the closed position of the two flap elements  10 . For this purpose, a spring leg  32  formed at the other end of the helical spring abuts against a stop  34  on the pre-cooler housing  4 . 
         [0024]    The exhaust gas duct  16 , or the two parallel exhaust gas ducts  16 , continue in the pre-cooler housing  4  and are deflected by 90° so that an exhaust gas outlet from the pre-cooler housing  4 , which is formed in a second flange  38 , is arranged perpendicularly to the exhaust gas inlet of the first flange  14 . It can be seen in  FIG. 2  that the two exhaust gas ducts  16  split into a plurality of exhaust gas ducts along the pre-cooler housing  4 , between which respective walls  40  are formed that are extended by connection with a non-illustrated exhaust gas cooler, as well as coolant ducts  42 ,  44  arranged outside are connected with a coolant jacket of the exhaust gas cooler that is connected with the coolant circuit of the internal combustion machine. The exhaust gas cooler is usually welded to the pre-cooler  2 . 
         [0025]    The pre-cooler housing  4  is fastened to the engine block by means of screws. For this purpose, the pre-cooler housing  4  has a plurality of domes  46  with throughholes formed thereon into which the screws can be inserted for fastening. 
         [0026]    For the pre-cooler housing  4  to assume its cooling function, the coolant ducts  42 ,  44  are formed in the pre-cooler housing  4 , two parallel coolant ducts  42  thereof extending in the region between the exhaust gas duct of the exhaust gas cooler and the engine block, and two coolant ducts  44  extending on the side of the exhaust gas cooler remote from the engine block. 
         [0027]    Whereas the coolant ducts  42  extend parallel to the surface of the first flange  14 , the coolant ducts  44  have a 90° deflection like the exhaust gas ducts  16 , i.e., they extend parallel to the exhaust gas ducts  16  on an outer wall  47  of the pre-cooler housing  4 . The exhaust gas ducts  16  are accordingly shielded by the coolant ducts  44  in the direction of the actuator  12 . 
         [0028]    According to the present invention, the coolant ducts  44  comprise coolant duct segments  48  arranged in the region between the actuator  12  and the engine block and extending parallel to the first flange  14  for the entire length of the actuator  12 . These coolant duct segments  48 , numbering two in the present embodiment, are in fluid communication via a connecting duct  50  so that a forward flow occurs in the first coolant duct segment  48 , while a return flow of the coolant occurs in the opposite segment, whereby dead water regions can be avoided in a reliable manner. 
         [0029]    Further, at this segment of the pre-cooler housing  4 , four eye-type bearings  52  are formed on the surface, through which the actuator  12  is fastened to the pre-cooler housing  4  by means of two screws  54  respectively inserted through two opposite eye-type bearings  52 . 
         [0030]    The cooler arrangement of the present invention thus achieves a full thermal shielding of the actuator  12  both from the engine block and from the exhaust gas duct  16  of the cooler arrangement, so that a reliable functionality of the actuator  12  can be provided over a long service life. Both in the region of the first flange  14 , where the heat input is the highest, and in the rest of the pre-cooler housing  4 , the present cooler arrangement allows for a high heat dissipation via the coolant, so that good cooling efficiencies result therefrom. Further, less costly materials can be used for the housings. Due to this good cooling effect of the pre-cooler, as well as the accommodation of an exhaust gas recirculation valve or a bypass flap in the same, a downstream heat exchanger can be built with significantly smaller dimensions, since the temperature is dissipated to a high extent directly at the inlet. The structure proposed is also suitable for large flow volumes, as encountered especially in utility vehicles. Otherwise necessary pipe lines can be omitted. 
         [0031]    It should be clear that various modifications to the described embodiments are possible within the scope of protection of the main claim. In particular, various valves may be integrated in the pre-cooler. The manufacturing and the structural design of the housing parts may also be modified depending on the application. For example, the first flange may be flanged to the pre-cooler housing as a separate component with the exhaust gas recirculation valve. Depending on the application, the number of coolant ducts and exhaust gas ducts may moreover be varied, in particular, only one exhaust gas duct may be formed in the housing, without departing from the scope of protection. 
         [0032]    The present invention is not limited to embodiments described herein; reference should be had to the appended claims. 
         [0033]    What is claimed is: