Abstract:
An air intake tract arrangement for an internal combustion engine includes an exhaust gas inlet device arranged at the inlet side of a charge air cooler and configured to direct injected EGR exhaust gas substantially in a direction towards an inlet of said charge air cooler, thereby enabling the use of plastic intake tract components.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     Priority is claimed based on Federal Republic of Germany patent application no. DE 20 2009 001 782.6 filed Feb. 12, 2009. 
     TECHNICAL FIELD 
     The invention relates generally to an exhaust gas inlet device for an air intake tract of an internal combustion engine with an charge air cooler integrated into the air inlet manifold. 
     BACKGROUND OF THE INVENTION 
     Plastic intake ducts and manifolds for the intake air of a turbo charged combustion engine wherein the EGR (exhaust gas recirculation) inlet into the combustion air flow is situated downstream from the charged air cooler are known. For an example configuration, the EGR inlet is integrated into the plenum of the manifold instead of being upstream from the throttle body. 
     In another known configuration the EGR inlet is positioned upstream of the charge air cooler. At this location air coming from the turbo charger at a temperature above 150 degrees C. has to be mixed with exhaust gas entering the air intake line at temperatures up to 700 degrees C. This mixing creates a flow at a temperature that could exceed the maximum acceptable temperature for plastics. Thus the parts of the intake tract around this mixing zone are required to be made of metal. 
     SUMMARY OF THE INVENTION 
     This invention enables the mixing of exhaust gas and combustion air from the turbo charger in a location upstream from the charge air cooler in an intake manifold made substantially of plastic material. Both or either of the intake manifold and/or the air ducts can be made substantially out of the plastic material. 
     To provide an air intake tract substantially made of plastic material the EGR injection is included in or located close to the charge air cooler module. 
     Preferably the inlet device injects the EGR substantially in the direction of the flow of the combustion air at a position in front of the inlet side of the charge air cooler. Preferably the injection is positioned close to the charge air cooler. In this way exhaust flow can mix in a zone spatially separated from the plastic parts of the air intake tract, thus the walls are not heated by the exhaust gas. The hot mixed flow may be directed to enter the charge air cooler directly. The temperature of the mixed flow is higher directly in the mixing zone and cooler in the area close to the walls of the air intake tract. A homogenous mixing can be supported by a multi point injection. The inlet device could be a tube with several bores in the direction of the charge air cooler. 
     Preferably the EGR inlet device is entering the air intake tract through a cooled flange. The cooled flange is preferably cooled by the charge air cooler. The cooled flange can be constructed in one alternative as a part of the charge air cooler, e.g. as integral part of a charge air module. The cooled flange enables a hot EGR inlet device to be fixed to the air intake tract made substantially from a plastic material. The cooled flange reduces heating of the air intake tract, e.g. by heat conduction from a metal inlet device to the plastic air intake tract. 
     The above features and advantages and other features and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying Figures, where like reference numerals refer to identical or functionally similar elements throughout the separate views and which together with the detailed description below are incorporated in and form part of the specification, serve to further illustrate various embodiments and to explain various principles and advantages all in accordance with the present invention. 
       Features of the present invention, which are believed to be novel, are set forth in the drawings and more particularly in the appended claims. The invention, together with the further objects and advantages thereof, may be best understood with reference to the following description, taken in conjunction with the accompanying drawings. The drawings show a form of the invention that is presently preferred; however, the invention is not limited to the precise arrangement shown in the drawings. 
         FIG. 1  depicts an air intake manifold of an internal combustion engine with an integrated water cooler to cool the charge air from a turbocharger, consistent with the present invention; 
         FIG. 2  shows a cross section through the intake manifold with a charge air cooler module arranged inside the plenum, consistent with the present invention; 
         FIG. 3  shows a cross section through another embodiment of the EGR inlet device arranged within an air intake duct, consistent with the present invention; and 
         FIG. 4  a side view of the module shown in  FIG. 3 . 
     
    
    
     Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention. 
     DETAILED DESCRIPTION 
     Before describing in detail embodiments that are in accordance with the present invention, it should be observed that the embodiments reside primarily in combinations of method steps and apparatus components related to an exhaust gas inlet device for a internal combustion engine including an charge air cooler integrated into the engine air intake tract as disclosed herein. Accordingly, the apparatus components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein. 
     In this document, relational terms such as first and second, top and bottom, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. The terms “comprises,” “comprising,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element preceded by “comprises . . . a” does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element. 
       FIG. 1  shows an air intake manifold  1  of an internal combustion engine with an integrated water cooler  2  to cool the charge air. The clean air for the combustion engine enters the manifold  1  at the air inlet flange  3  through a throttle body. The air enters the plenum  4  of the manifold  1  and flows through the cooler  2  through a second plenum  4 ′ into the inlet ports  5  of the combustion engine. Inside the plenum  4  upstream the cooler  2  there is an EGR (exhaust gas recirculation) inlet device  6  with outlets  7  for the hot exhaust gas which directs the exhaust gas towards the cooler  2 . On the outside of the EGR inlet device  6  there is a flange  9  providing an inlet port  8  for the exhaust gas and a connection to the exhaust gas system. 
     The air cooler can be made with a water circulation system transferring the heat of the exhaust gas and the fresh air through ribs to the water. Other possible alternative of air coolers are known to a person skilled in the art. 
     The EGR inlet device  6  can be made in one part with (integrated with) the air cooler  2  as a unitary module to reduce number of parts and assembly steps. 
     The module (EGR device  6 +charge air cooler  2 ) can be slidably inserted into an opening at one side of the manifold  1  and configured such that the flange  9  closes the manifold at the mounting flange tightly after assembling. 
     In another advantageous solution the manifold  1  can be assembled of several parts with one part being the air cooler  2 . 
       FIG. 2  shows a cross section through the intake manifold  1  with a charge air cooler module  10  positioned inside the plenum  4 . The air flows from the inlet flange  3  through the charge air cooler into the inlet ports  5  of the internal combustion engine. 
     The water circulates from the inlet  11  on the outside of the module through the charge air cooler to the outlet  2 . Upstream of the air cooler  2  the charge air is mixed with the exhaust gas in a region between the charge air cooler  2  and the EGR inlet device  6 . The EGR inlet device  6  has outlets  7  directed towards the cooler. The EGR inlet device  6  is surrounded by the air entering the manifold  1 . 
       FIG. 3  shows a cross section through another embodiment of the EGR inlet device in an air intake line. The air flow from the turbo charger enters a first plenum  14  through an air inlet  13  and passes through the charge air cooler  22  before entering a second plenum  14 ′ upstream the air outlet  15  towards the combustion engine. 
     Inside the plenum there is an EGR inlet device  16  positioned upstream before the cooler  22  with EGR outlet ports  17 . The charge air cooler is passed through by water entering the charge air cooler module  10  by an inlet port  11  and leaving at an outlet port  12 . The housing of the intake duct or line is made of plastic material, the plastic material in this and other embodiments is preferably a polyamide 6,6 or in another alternative polyamide 6, both preferably including glass fibers. 
       FIG. 4  depicts a side view of the module shown in  FIG. 3  is shown. The exhaust gas EGR enters the EGR inlet device  6  at the inlet port  8 . The EGR device  6  has a ring structure with several outlet ports  7  distributed at the ring adjacent to the cooler  22 . The exhaust gas enters the central region at the inlet of the charge air cooler  22 , spatially isolated from the plastic plenum  14  and inlet duct  13 . 
     In the foregoing specification, specific embodiments of the present invention have been described. However, one of ordinary skill in the art appreciates that various modifications and changes can be made without departing from the scope of the present invention as set forth in the claims below. Accordingly, the specification and figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of the present invention. The benefits, advantages, solutions to problems, and any element(s) that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as a critical, required, or essential features or elements of any or all the claims. The invention is defined solely by the appended claims including any amendments made during the pendency of this application and all equivalents of those claims as issued.