Patent Publication Number: US-7210461-B2

Title: Internal combustion engine for a motor vehicle

Description:
BACKGROUND OF THE INVENTION 
     The invention pertains to an internal combustion engine for a motor vehicle with a cylinder head, an intake manifold, and a fuel distributor rail,
         where the downstream end of the intake manifold is connected by a flange to the intake channels in the cylinder head of the internal combustion engine,   where the fuel distributor rail is located at the downstream end of the intake manifold and is connected to fuel injection valves, and   where the internal combustion engine is installed in the motor vehicle in such a way that the intake manifold is located on the side of the cylinder head on which the external crash force will act during a crash.       

     EP 0732 495 B1 describes an intake manifold for an internal combustion engine of a motor vehicle which has at least one intake manifold channel, where at least one of the intake manifold channels has a predetermined break zone, which is essentially parallel to the longitudinal direction of the channel. This gives the intake manifold better behavior in a crash. When a crash occurs, the intake manifold breaks along the predetermined break zone on the longitudinal axis and thus absorbs some of the energy of the crash. 
     A protective device for a fuel rail is known from U.S. Pat. No. 6,77,132 B2. This device is located underneath the intake manifold and is attached to the fuel rail. When a crash occurs, the protective device wraps itself plastically around the fuel rail and thus protects the fuel line from damage which might otherwise have been caused by the deformation of the intake manifold. The intake manifold absorbs some of the impact energy, and the fuel line remains undamaged. Thus, no fuel is able to leak out. 
     SUMMARY OF THE INVENTION 
     The invention is based on the task of improving an internal combustion engine of the type indicated above with respect to the safety offered in a crash. 
     This task is accomplished according to the invention by an internal combustion engine of the type indicated above, wherein a protective strap which extends at least over the entire width of the flange is attached to the cylinder head. The protective strap is located in such a way that, based on the direction of the crash force, it is a certain distance in front of the fuel distributor rail and, based on the direction in which the intake manifold will deformed upstream of the flange during a crash, this direction being at an angle to the direction of the crash force, a certain distance behind the intake manifold. 
     This offers the advantage that, because of the protective strap is supported on the cylinder head, it will, in the event of a crash, introduce forces into the deforming intake manifold upstream of the flange, as a result of which the point at which the intake manifold will break is shifted forward and the flange itself is relieved of load. Any fragments into which the deforming intake manifold may break will be produced far away from the fuel distributor rail and will be unable to approach to bar too closely. This effectively reduces the danger of damage to the fuel distributor rail which might otherwise be caused by fragments of the intake manifold. The intake manifold is thus effectively prevented from becoming deformed in the area between the protective strap and the flange, that is, in the area where the fuel distributor rail is located, and the flange is prevented from fracturing—either of which events could lead to damage to the fuel distributor rail. 
     It is advisable for the intake manifold to be designed as a one-piece intake manifold. 
     In another embodiment, the intake manifold has a section with intake channels, on at least one of which a predetermined breaking point is provided. The channel will break at this point during a crash, so that the intake can effectively absorb some of the crash energy. 
     The predetermined break point is preferably designed as a break line formed by a reduction in the thickness of the channel wall. The break line can be perpendicular, for example, to the longitudinal direction of the intake channel. 
     Another way of isolating the fuel distributor rail from the effects of the deformation of the intake manifold channels during a crash is to attach the fuel distributor rail not to the intake manifold itself but rather to the means by which the protective strap is fastened to the cylinder head. 
     The protective strap is preferably so stiff that it can resist the attempts of the crash force to deform it. As a result, a gap is maintained between the protective strap and the fuel distributor rail, and thus the protective strap also provides mechanical protection in the event of a crash. 
     The invention is explained in greater detail below on the basis of the drawing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         FIG. 1  shows a perspective view of a preferred embodiment of an inventive internal combustion engine pursuant to the present invention; and 
         FIG. 2  shows a detailed view, in perspective, of the intake manifold, the fuel distributor rail, and the protective strap of the inventive internal combustion engine according to  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The embodiment of an inventive internal combustion engine illustrated in  FIGS. 1 and 2  for a motor vehicle (not shown) comprises a cylinder head  10 , an intake manifold  12 , and a fuel distributor rail  14 . The downstream end of the intake manifold  12  is connected by a flange  15  to the intake channels in the cylinder head  10 . The fuel distributor rail  14  is located at the downstream end of the intake manifold  12  and is connected to fuel injection valves (not shown). The internal combustion engine is installed in the motor vehicle in such a way that the intake manifold  12  is located on the side of the cylinder head  10  on which an external crash force  16  will act during a crash. The intake manifold  12  comprises an intake plenum  18  and intake channels  20 , which divide the air stream into individual substreams, one of which is sent to each cylinder of the internal combustion engine. 
     The expression “during a crash” used here describes a state in which a motor vehicle equipped with the inventive internal combustion engine strikes an obstacle, whereupon at least some of the kinetic energy of the vehicle is absorbed by deformation. In general, this involves the collision of the front end of the motor vehicle, i.e., the end facing in the direction of travel, with an obstacle, so that the front area of the vehicle is deformed and kinetic energy is absorbed there (front-end collision). When the vehicle strikes an obstacle in this way, the crash force therefore acts in the direction opposite that of vehicle travel. Parts of the chassis of the vehicle and components of the internal combustion engine in the engine compartment such as the intake manifold will be deformed. Use is made of the intake manifold in particular as an effective way of absorbing some of the crash energy through the deformation of the intake channels  20 . 
     According to the invention, a protective strap  22  is attached to the cylinder head  10 . This strap  22  extends at least over the entire width of the flange  15  and is arranged in such a way that the protective strap  22 , based on the direction of the crash force  16 , is a certain distance in front of the fuel distributor rail  14  and, based on the direction  24  in which the intake manifold  12  will be deformed upstream of the flange  15  during a crash, this direction being at an angle to the direction of the crash force  16 , that is, not parallel to it, a certain distance behind the intake manifold  12 . 
     As a result, a protected area of the intake manifold  12  is created between the protective strap  22  and the flange  15 , an area which cannot be deformed during a crash. If, during a crash, the intake channels  20  are pushed upward, that is, in the direction of the arrow  24  ( FIG. 1 ), the protective strap  22  prevents such movement in the protected area and instead transmits the forces to the intake manifold  12  at a point farther away from the flange  15  and from the fuel distributor rail  14 . If the intake manifold  12  breaks as a result of the crash, this break will therefore occur a certain distance away from the fuel distributor rail  14 . Any fragments of the intake manifold  12  which may break off will be produced relatively far away from the fuel distributor rail  14  and thus will be unable to damage it. The protective strap  22  also prevents breakage of the intake channels in the area of the flange  15 , so that no damage to the fuel distributor rail  14  can occur as a result of this either. Thus the protective strap  22  both provides mechanical protection for the fuel distributor rail  14  and prevents the deformation of the intake manifold  12  in the area of the fuel distributor rail  14 . 
     In the event of a crash, however, the protective strap  22  remains firmly in place because of its rigid connection to the cylinder head  10  and thus defines a deformation-free zone between itself and the flange  15 . This is the zone in which the fuel distributor rail  14  is located. The protective strap  22  thus causes the intake manifold  12  to be destroyed intentionally in noncritical areas by transmitting stresses into a forward area of the one-piece intake manifold  12  during a crash. As a result, a low-cost, one-piece intake manifold design can be retained, which is nevertheless still able to provide increased safety against damage to the fuel distributor  14  in the event of a crash. 
     For the effective absorption of crash energy, the intake channels  20  are also provided with a break line  26  ( FIG. 2 ), essentially perpendicular to the longitudinal direction of the intake channels  20 . This break line  26  represented the predetermined place where the channels  20  will break during a crash and is produced, for example, by reducing the wall thickness of the intake channels  20  along the break line. 
     The inventive arrangement and design of the protective strap  22  guarantees that, in the event of a crash, no fuel will be able to leak our and that none of the components deformed by the crash force  16  will be able to contact the fuel distributor rail  14 . The seat of the injection valves located underneath the fuel distributor rail  14  will not be destroyed either, because a deformation-free zone is created between the protective strap  22  and the flange  15 . 
     The protective strap  22  takes over the function of introducing stresses to a forward area of the intake manifold  12  and thus relieves the flange  15  of load. The flange  15  is therefore effectively prevented from being broken even in extreme situations. In the event of a crash, the protective strap  22  prevents the intake channels  20  from being deflected upward in the direction of arrow  24  and transmits the additional stresses into the forward area of the intake manifold  12 . During a crash, the intake manifold  12  will therefore fail at the appropriately intended predetermined break points, which in any case are far enough away from the fuel distributor rail  14  that fragments of the intake manifold  12  cannot cause any damage to the fuel distributor rail  14 . The protective strap  22  thus also protects the fuel distributor rail  14 . 
     As a result, the “up-front” arrangement of the intake manifold in the crash area can be retained. Such an arrangement is necessary for engine designs in which the air filter is permanently connect to the engine. The low-cost concept of a one-piece intake manifold  12  can also be retained. The protective strap  22  has the primary function of influencing the breakage behavior of the intake manifold  12  during a crash and the secondary function of protecting the fuel distributor rail  14  from broken pieces. 
     Because the protective strap  22  is supported laterally against the flange  15 , the breaking stress is introduced into noncritical areas, and in the event of a crash the intake manifold  12  will break before the fuel distributor  14  can be damaged. 
     Thus, while there have been shown and described and pointed out fundamental novel features of the present invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the present invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Substitutions of elements from one described embodiment to another are also fully intended and contemplated. It is also to be understood that the drawings are not necessarily drawn to scale but that they are merely conceptual in nature. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.