Abstract:
An air intake device for an internal combustion engine which includes at least one collection manifold and intake ducts branching off separately to individual cylinders of the internal combustion engine. The intake lines extend to the collection manifold and are formed at least partially of a flexible tube, especially a rubber tube. The intake lines furthermore have stiff or variable-length portions which are divided into at least two segments disposed for movement independently of one another.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to an air intake device for internal combustion engines with at least one collection manifold and intake tubes branching separately to the individual cylinders of the internal combustion engine, in which the intake tubes extend to the collection manifold and are formed at least partially by a flexible element. 
     Published German Patent Application No. DE 197 17 272 discloses an air intake apparatus for an internal combustion engine, which has an air collection manifold and individual air channels to the individual cylinders. Adjustable intake tube extensions are associated with the air channels. These air channel extensions comprise setting devices with rocker systems and pantograph-like levers. A disadvantage of this construction lies in the complicated drive mechanism of the intake tube extensions. Especially in internal combustion engines which are used in motor vehicles, there is a danger that these mechanical components may become impaired by environmental influences. Any failure of the mechanisms inevitably leads to a loss of power. 
     Air intake devices for internal combustion engines are also known which have intake lines made of a flexible tubing. This flexible tubing is contained within a closed system, but a disadvantage of this construction is that the walls of the tubing are ribbed for flexibility, and this needlessly increases resistance to air flow. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide an air intake system which avoids the aforementioned disadvantages. 
     Another object of the invention is to provide an air intake device which will have a positive influence on the power of an internal combustion engine with which it is used. 
     A further object of the invention is to provide an air intake device which will have a simple and reliable construction. 
     It is also an object of the invention to provide an air intake device which will not substantially increase resistance to flow. 
     These and other objects have been achieved in accordance with the present invention by providing an air intake device for an internal combustion engine, said device comprising at least one collection manifold and a plurality of intake tubes which branch separately from the collection manifold to individual cylinders of the internal combustion engine, wherein each of the intake tubes extends to the collection manifold and is formed at least partially by a flexible element, and said intake tubes comprise stiff or variable-length portions, which portions are divided into at least two segments mounted so as to be moveable independently of one another. 
     A significant advantage of the invention is that the intake tubes comprise different regions or segments, and it is possible to couple and decouple the various segments. 
     In accordance with one embodiment of the invention, the various segments are journaled on a common pivot center. This eliminates complicated linkages or drive systems. The common center permits the necessary adjusting movements to be carried out in a simple manner. 
     In another embodiment of the invention the segments are longitudinally displaceable. This is especially practical where the segments consist of short pieces of tubing. Of course, it is also possible to combine longitudinally displaceable segments with rotary segments in order to make optimal use of available space. 
     In a further embodiment the segments are provided with radial and/or axial gaskets at their coupling points. These gaskets assure optimum coupling and prevent the entry of extraneous air. 
     Another embodiment of the invention describes the overall structure of an air intake device in which rigid first element is coupled to a rotatable or longitudinally moveable second element, which in turn can be coupled to a rigid third element. The longitudinally movable element is equipped at the coupling points with sections of variable length. 
     These and other features of preferred embodiments of the invention, in addition to being set forth in the claims, are also disclosed in the specification and/or the drawings, and the individual features each may be implemented in embodiments of the invention either individually or in the form of subcombinations of two or more features and can be applied to other fields of use and may constitute advantageous, separately protectable constructions for which protection is also claimed. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be described in further detail hereinafter with reference to illustrative preferred embodiments shown in the accompanying drawings in which: 
     FIGS. 1 a-c  show an air intake device with two movable segments; 
     FIGS. 2 a-c  show a first variant of the air intake device with a moveable intermediate segment; 
     FIGS. 3 a-c  show another variant of an air intake device with compressible portions at the coupling ends of first and third tube segments; 
     FIGS. 4 a-c  show an air intake device with a flat housing structure; 
     FIGS. 5 a-c  show an air intake device with an intermediate element which is displaceable lengthwise; 
     FIGS. 6 a-c  show a detail of a longitudinally displaceable intermediate element; and 
     FIGS. 7 a-c  show a system with an axially movable intermediate element. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The air intake device comprises a housing  10  which is provided with a flange  11  to fasten the housing to an internal combustion engine, not shown here. Beginning from the flange  11  a fixed intake tube  12  is arranged in the housing  10 . This intake tube is adjoined by two moving intake tube segments  13  and  14 . These intake tube segments are journaled at a common pivot point  15 . The mounting of the intake tube segments  13  and  14  is in the form of a suitable supporting structure  16 ,  17 . In the position shown in FIG. 1 a , the intake tube segments  13  and  14  are spaced apart, i.e., the intake air for the internal combustion engine flows directly according to the arrow  19   a  into the intake tube  12  and from there to the internal combustion engine. This position is the so-called power position and achieves a high torque at high speeds of the internal combustion engine. 
     FIG. 1 b  shows the air intake device in which the intake tube segment  13  is coupled to the intake tube  12 . For this purpose the corresponding coupling gaskets  18  are provided. The air now flows according to arrow  19   b  through the intake tube segment  13  and intake tube  12  into the internal combustion engine. This position provides for optimum torque, especially at low engine speeds. 
     FIG. 1 c  shows the coupling of intake tube segment  14  to segment  13  and intake tube  12 . The air now flows over the longest path into the internal combustion engine. Appropriate gaskets may be provided between the individual segments provide for a reliable seal. 
     FIGS. 2 a  through  2   c  show a first variant of the air intake device. Between the individual segments  13  and  14  and the intake tube  12 , variable length gaskets  20  and  21  are provided. In the position shown in FIG. 2 a , the air intake device forms the longest intake path. FIG. 2 b  shows the uncoupling of segment  14 . At the same time segment  13  enters partially into intake tube  12 . In FIG. 2 c  the segment  13  is swung away from intake tube  12 . The intake air flows directly into intake tube  12 . The advantage of the construction shown in FIG. 2 is that the segment  14  is itself fixedly arranged in the housing. only segment  13  is pivotally mounted. The turning of segment  13  is permitted by the axially displaceable gaskets  20  and  21 , which simultaneously serve as mountings to support the ends of the segments inserted in the adjacent segments. 
     FIGS. 3 a  through  3   c  show another variant of the air intake device. Here the segment  14  is fixedly disposed in the housing  10 . Flexible connection sections  22  and  23  are provided on segment  14  and on intake tube  12 . The rotation of segment  13  produces a compression or stretching of these connection sections and thus, as can be seen in FIG. 3 b , an opening between the segment  13  and segment  14  and, as shown in FIG. 3 c , an opening between the intake tube  12  and segment  13 . 
     FIGS. 4 a  through  4   c  show an air intake device with a shallow housing structure. The housing  24  is provided with a segment  25  and an intake tube  26 . A pivotable element  27  is journaled in the housing. A counter-clockwise rotation of the pivotable element  27  results in a compression of the intake area  22  and simultaneously in an opening between segment  25  and turning element  27 . A clockwise rotation of this turning element  27  leads to a compression of the connection  23  and an opening of the intake tube  26 . In this position the intake air flows directly into the short intake tube. 
     FIGS. 5 a  through  5   c  show an air intake device with a longitudinally displaceable intermediate element. The intermediate element  28  is moved in the direction of the arrow  30 . In the position shown in FIG. 5 a  it connects the intake tube  31  to element  32 . In FIG. 5 b , the intermediate element  28  has shifted toward the intake tube  31  and element  32  is uncoupled. In the position shown in FIG. 5 c  the intermediate element is shifted in the opposite direction and opens the intake tube  31  to provide a short intake path. 
     FIGS. 6 a  through  6   c  show a detail of the intermediate element  28  similar to that described in FIG. 5 except that the compressible sections are mounted on the ends of the end tubes  35  and  36  instead of on the center segment  28 . At its axial ends, the intermediate element carries connecting bells  33  and  34 , which in the position shown in FIG. 6 a  accommodate the flexible ends of the two pipe sections  35  and  36 . In the illustrated embodiment, the intermediate element  28  is fixedly disposed. This signifies that none of the pipe sections is movably mounted. Only the flexible ends of the two pipes  35  and  36  are longitudinally displaceable by means of pushers  37  and  38 . FIG. 6 b  shows a movement of the pusher  37  to the right. This opens a passage  39  between tube  28  and tube  36 . FIG. 6 c  shows a movement of the pusher  38  to the left. This opens the passage  40  between tube  28  and tube  35 . 
     FIG. 7 a  shows shows an intake tube with an intermediate element  28  shifted to a leftward position. The seal between the intermediate element  28  and the pipe  41  is provided by a radial gasket  42  and a seal  44  biased by a compression spring  43 . FIG. 7 b  shows the intermediate element  28  shifted to a rightward position. The seal between intermediate element  28  and the end tube is provided in the same way as on the opposite end by means of a compression spring  45 , a seal  46  and a radial gasket  47 . FIG. 7 c  shows the intermediate element  28  in a mid-position in which sealing is provided at both ends. 
     The foregoing description and examples have been set forth merely to illustrate the invention and are not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed broadly to include all variations falling within the scope of the appended claims and equivalents thereof.