Abstract:
A device for turbocharging an internal combustion engine including a turbocompessor including a turbine driven by the engine exhaust gas and a compressor driven by the turbine and compresses the engine intake air. An air intake conduit connects the compressor output to an air intake manifold to the engine and includes a chamber for damping pulsations generated at the compressor output. The damping chamber is connected directly to the compressor output.

Description:
BACKGROUND 
     The present invention relates to a turbocharger device of an internal combustion engine comprising a chamber for damping the pulsations generated at the outlet of the compressor. 
     A device of this type is described in particular in patent applications JP 57049021 and 12330280. 
     In these patent applications, a first damping chamber is situated mid-way on the air intake duct that connects the outlet of the compressor to the intake manifold of the engine. 
     Also, one or two other damping chambers are placed on ducts connected to the section of the intake duct lying between the compressor and the first damping chamber. 
     The chambers reduce the amplitude of the pressure pulsations in the intake duct by an interaction of damping and resonance effects. 
       FIGS. 1 and 2  appended illustrate the prior art closest to the invention. 
     In  FIG. 1 , reference number  1  indicates a turbocharger comprising a turbine  2  driven by the gases flowing in the exhaust duct  3  of the internal combustion engine  4 . 
     The turbine  2  drives the rotor  5  of the compressor  6  which sends the compressed air into the intake duct  7  connected to the intake manifold  8  of the engine  4 . 
     The intake duct  7  comprises on its path a chamber  9  whose structure is detailed in  FIG. 2 . 
     To make the intake duct  7  easier to install on the outlet endpiece  10  of the compressor  6 , the end  11  of the duct  7  is attached around the endpiece  10  by snap-fitting means comprising a retaining clip  19 . 
     The damping chamber  9  comprises a cylindrical external wall  12  which surrounds a cylindrical internal wall  13  whose diameter is substantially equal to that of the intake duct  7 . 
     Between the cylindrical walls  12  and  13 , two annular spaces  14  and  15  separated from one another by a partition  16  are created. Each space  14 ,  15  opens into the inside of the duct  7  through an annular slot  17 ,  18 . 
     The damping chamber assembly is made of several elements welded together. 
       FIG. 2  shows in detail the snap-fitting of the end  11  of the intake duct  7  around the outlet endpiece  10  of the compressor  6 . 
     The end  11  of the duct  7  has a shape that is flared toward the compressor comprising an annular shoulder  24  which rests on the end of a sleeve  23  that surrounds the outlet endpiece  10  of the compressor. 
     The flared end  11  of the duct  7  is snap-fitted to the sleeve  23  thanks to a retaining clip  19 . Between the end  11  and the sleeve  23 , seals  20 ,  21  are inserted. 
     BRIEF SUMMARY 
     The object of the present invention is to provide enhancements to the above known device by simplifying its construction while improving the effectiveness of the damping chamber. 
     According to the invention, the device for turbocharging an internal combustion engine comprising a turbocharger whose turbine is driven by the exhaust gases of the engine and whose compressor driven by this turbine compresses the engine intake air, the air intake duct linking the outlet of the compressor to the air intake manifold to the engine, comprising a chamber for damping the pulsations generated at the outlet of the compressor, is characterized in that said damping chamber is directly connected to the outlet of the compressor. 
     This arrangement makes it possible to simplify the construction while increasing the effectiveness of the damping chamber. 
     According to a preferred version of the invention, said damping chamber partially surrounds a tubular endpiece connected to the outlet of the compressor. 
     Preferably, said damping chamber comprises an external cylindrical wall and an internal wall between which two contiguous annular spaces are made and the internal wall of one of the annular spaces surrounds said outlet endpiece of the compressor. 
     This internal wall therefore forms the end of the intake duct which is adapted around the outlet endpiece of the compressor, which simplifies the construction of the device. 
     According to other particular features of the invention:
         said damping chamber comprises, in a radial plane situated substantially in its middle, a partition having a circular central opening whose diameter is substantially equal to the diameter of the tubular endpiece connected to the outlet of the compressor;   said central opening is extended in a direction opposite to said endpiece by a tubular duct defining, with the external wall of said damping chamber, an annular space which opens toward the air intake duct via an annular opening formed between the free end of said tubular duct and the zone for connecting said chamber with the air intake duct;   said damping chamber has another annular space in a zone extending between said annular partition and the zone for connecting said damping chamber with the outlet of the compressor;   said other annular space opens radially toward the axis of the outlet endpiece of the compressor via a circular slot adjacent to the edge of said circular opening;   the outlet endpiece of the compressor is surrounded annularly by a sleeve attached around the outlet of the compressor, the end of the external wall of the chamber opposite to the air intake duct being snap-fitted around said sleeve,   said sleeve is surrounded by a tubular element one end of which comprises a rim resting on the outlet edge of said outlet endpiece and the other end of which is inserted between said outlet endpiece and the adjacent end of the external wall of the chamber and is attached to said sleeve by the means used to snap-fit the end of the external wall of the chamber to said sleeve.       

    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Other features and advantages of the invention will still appear in the following description. 
       In the appended drawings, given as nonlimiting examples: 
         FIG. 1  is a schematic view in longitudinal section of a turbocharger device comprising a known damping chamber, 
         FIG. 2  is a partial view of the device according to  FIG. 1 , showing the detailed structure of the damping chamber and of the connection of the intake duct to the outlet of the compressor, 
         FIG. 3  is a view similar to  FIG. 1  illustrating the device according to the invention, 
         FIG. 4  is a view similar to  FIG. 2 , showing the damping chamber of the device according to the invention and its direct connection to the outlet of the compressor. 
     
    
    
     DETAILED DESCRIPTION 
     In  FIG. 3 , the portions identical to those of  FIG. 1  bear the same reference numbers. 
     As shown by this  FIG. 3 , the turbocharger device of an internal combustion engine  4  comprises a turbocompressor  1  whose turbine  2  is driven by the exhaust gases  3  of the engine  4  and whose rotor  5  of the compressor  6  driven by this turbine  2  compresses the intake air of the engine. 
     The air intake duct  7  connecting the outlet  10  of the compressor  6  to the air intake manifold  8  to the engine  4  comprises a chamber  9   a  for damping the pulsations generated at the outlet endpiece of the compressor  6 . 
     According to the invention, this damping chamber  9   a  is directly connected to the outlet endpiece  10  of the compressor  6 . 
     As can be seen in  FIGS. 3 and 4 , the damping chamber  9   a  partially surrounds the tubular endpiece  10  connected to the outlet of the compressor  6 . 
     As in the case of  FIGS. 1 and 2 , the damping chamber  9   a  comprises an external cylindrical wall  12   a  and an internal wall  13   a ,  13   b  between which two contiguous annular spaces  14   a ,  15   a  are made. 
     In the case of  FIGS. 3 and 4 , the internal wall  13   a  of the annular space  14   a  almost entirely surrounds the outlet endpiece  10  of the compressor. 
     The damping chamber  9   a  comprises, in a radial plane situated substantially in its middle, a partition  16   a  having a circular central opening  20   a  whose diameter is substantially equal to the diameter of the outlet endpiece  10  connected to the outlet of the compressor. 
     This central opening  20   a  is extended in a direction opposite to the outlet endpiece  10  by a tubular duct  13   b  defining, with the external wall  12   a  of the damping chamber  9   a , an annular space  15   a.    
     This annular space  15   a  opens toward the air intake duct  7  via an annular opening  18   a  formed between the free end of the tubular duct  13   b  and the zone  21  for connecting the chamber  9   a  with the air intake duct  7 . 
       FIG. 4  shows that the tubular duct  13   b  has a shape that is flared in the opposite direction from its central intake opening  20   a.    
     Furthermore, the damping chamber  9   a  has an annular space  14   a  in a zone extending between the annular partition  16   a  and the zone  22  for connection of the damping chamber  9   a  with the outlet of the compressor. 
     The annular space  14   a  opens radially toward the axis of the outlet endpiece  10  of the compressor via a circular slot  17   a  adjacent to the edge of the circular opening  20   a  of the partition  16   a.    
       FIG. 4  also shows that the outlet endpiece  10  of the compressor is surrounded annularly by a sleeve  23   a  attached around the outlet endpiece  10  of the compressor. 
     In addition, the end  22  of the external wall  12   a  of the chamber  9   a  opposite to the air intake duct  7  is snap-fitted around the sleeve  23   a.    
     Furthermore, the sleeve  23   a  is surrounded by a tubular element which consists of the internal wall  13   a  of the internal space  14   a  of the chamber  9   a.    
     One of the ends of this wall  13   a  comprises a rim  24   a  resting on the outlet edge of the outlet endpiece  10 . 
     The other end of this wall  13   a  is inserted between the sleeve  23   a  and the adjacent end  22  of the external wall  12   a  of the chamber  9   a  and is attached to the sleeve  23   a  by the means comprising a clip  19   a  used to snap-fit the end of the external wall  12   a  of the chamber  9   a  to said sleeve  23   a.    
     As in the case of  FIG. 2 , several seals are inserted between the wall  13   a  defining the space  14   a  and the sleeve  23   a.    
     The main advantages of the device according to  FIGS. 3 and 4  relative to that of  FIGS. 1 and 2  are as follows: 
     It is less costly to produce mainly because the internal wall  13   a  of the chamber  9   a  is shaped to be able to be snap-fitted to the sleeve  23   a  which surrounds the outlet endpiece  10  of the compressor. 
     The internal wall  13   a  therefore has a dual function, because it replaces the two walls  13  and  11  of the device represented in  FIGS. 1 and 2 . 
     Furthermore, the other internal wall  13   b  of the chamber  9   a  can be produced in a single piece (as shown in  FIG. 4 ) with the partition  16   a , which saves on a weld. 
     In addition, because the damping chamber  9   a  is situated as close as possible to the compressor, an improvement of its effectiveness is noted and a reduction in the space requirement between the compressor and the intake manifold of the engine is obtained.