Abstract:
A unit carrier for secondary units of a motor vehicle internal combustion engine, having secondary unit attachment devices and engine block attachment devices. The unit carrier has a planned deformation point, which allows a relative displacement between the secondary unit and the engine block in case of a vehicle collision, if a predefined force is exceeded. The unit carrier is used in motor vehicles having a front engine arrangement.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a unit carrier for secondary units of a motor vehicle internal combustion engine, having secondary unit attachment devices and engine block attachment devices. The invention also relates to an internal combustion engine for a motor vehicle having at least one secondary unit and one secondary unit carrier.  
         [0003]     2. The Prior Art  
         [0004]     A unit carrier for an internal combustion engine, which has secondary unit attachment devices and engine block attachment devices, is known from German Patent No. DE 195 43 350 C1. The unit carrier attaches a generator to the internal combustion engine. The secondary unit carrier is attached to a face of the internal combustion engine, and is formed by the control housing-cover. The secondary unit carrier is reinforced by means of a carrier structure that is arranged in a framework manner between the holders for the secondary units and has cross-ribs and struts connected with them. By means of the arrangement of the cross-ribs and struts, an extremely rigid control housing cover is created, by way of which an introduction of force of the secondary units into the motor housing can take place.  
       SUMMARY OF THE INVENTION  
       [0005]     It is therefore an object of the invention to improve the crash behavior of motor vehicles. According to the invention, a unit carrier for secondary units of a motor vehicle internal combustion engine, having secondary unit attachment devices and engine block attachment devices, is provided. The unit carrier has a planned deformation point which allows a relative displacement between the secondary unit and the engine block in case of a vehicle collision, if a pre-defined force on a secondary unit is exceeded.  
         [0006]     By providing a planned deformation point, a block formation of secondary units and engine block in case of a crash is avoided, and the risk of penetration of the engine block into the passenger compartment of the motor vehicle is reduced. In this connection, block formation refers to the behavior of the engine with the secondary units as a single, rigid structure, which is displaced as a whole in case of a crash, without absorbing any impact energy. With the unit carrier according to the invention, in case of a crash, the engine block and secondary units can be displaced, relative to one another. This increases the deformation possibilities of a motor vehicle and, in case of a crash, more energy can be absorbed by car body parts or other components, by avoiding the block formation.  
         [0007]     In one embodiment of the invention, the planned deformation point is formed between the secondary unit attachment devices and the engine block attachment devices.  
         [0008]     In this manner, the planned deformation point can be formed independent of the configuration of the secondary unit attachment devices and the engine block attachment devices. This facilities the use of conventional secondary units and conventional engine blocks. Furthermore, in the case of a less severe vehicle collision, it can be assured that the secondary units and the engine block remain essentially undamaged, and merely the unit carrier has to be replaced.  
         [0009]     In addition, the planned deformation point is preferably configured as a planned breakage point. By means of these measures, part of the impact energy can be dissipated by having the unit carrier shear off at planned breakage points provided for this purpose, and a great displacement between the secondary unit and the engine block is made possible by having the unit carrier shear off. In this case, the secondary unit can be prevented from freely flying around, for example by additionally securing the secondary unit with a strap, or by securing the secondary unit with the drive belt or a drive chain, which is provided in any case.  
         [0010]     In a further development of the invention, the planned deformation point is configured such that in case of a vehicle collision, controlled deformation of the planned deformation point and dissipation of impact energy takes place, with a relative displacement between the secondary unit and the engine block. In this manner, the unit carrier can support controlled energy dissipation in case of a collision.  
         [0011]     The invention also includes an internal combustion engine having at least one secondary unit and one secondary unit carrier, wherein a front delimitation of the unit carrier and/or the at least one secondary unit lies in front, relative to a front delimitation of the engine block, seen in a collision direction to be expected here.  
         [0012]     By means of such target placement of the unit carrier and/or the secondary units in front, early contact of the combination of engine block and secondary units with the other party in the accident is produced. In this manner, the internal combustion engine can participate in the delay at an earlier point in time, and dissipation of energy can take place via displacement of the entire internal combustion engine, or also by means of a deformation of the unit carrier. In this connection, the planned deformation point of the unit carrier can be designed in different ways, so that either the unit carrier is deformed or shears off before any displacement of the engine block, or the unit carrier is deformed or shears off only after displacement of the engine block and a further increase in forces. In each case, block formation of the engine block and secondary units during the collision is avoided, and the risk of penetration of the engine block into the interior is reduced. Because energy also can be dissipated by the unit carrier according to the invention during a collision, the surrounding car body parts can be designed to be lighter, for example, since they no longer have to absorb the complete impact energy. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]     Other objects and features of the present invention will become apparent from the following detailed description considered in connection with the accompanying drawings. It is to be understood, however, that the drawings are designed as an illustration only and not as a definition of the limits of the invention.  
         [0014]     In the drawings, wherein similar reference characters denote similar elements throughout the several views:  
         [0015]      FIG. 1  shows a schematic top view of an internal combustion engine according to the invention, in the installed state, with a unit carrier; and  
         [0016]      FIG. 2  shows a schematic representation of the internal combustion engine of  FIG. 1 , after a vehicle collision. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0017]     Referring now in detail to the drawings,  FIG. 1  schematically shows an internal combustion engine  10  having an engine block  12 , which is connected with a motor vehicle by two engine bearings  14 . A forward travel direction of the motor vehicle is indicated by arrow  16 . Opposite forward travel direction  16 , a clutch bell  18  and a transmission  20  follow engine block  12 . The internal combustion engine  10  is arranged in an engine space (not shown) of the motor vehicle. Bearing points  15  that are fixed on the car body are indicated, and a rear delimitation of the engine space is represented by the indicated contour  22  of a water tank. Opposite the forward travel direction  16 , a vehicle interior follows contour  22  of the water tank.  
         [0018]     Seen in the forward travel direction  16 , a unit carrier  24  is attached to one face of engine block  12 , with several secondary units attached to this carrier, for example a generator  26  and a refrigerant compressor  28 . Generator  26  and refrigerant compressor  28  are driven by a drive belt  30 , which in turn is driven by a pulley arranged on a crankshaft continuation  32 .  
         [0019]     Seen in forward travel direction  16 , a radiator  34  follows drive belt  30 , and a front delimitation of the motor vehicle is formed by a front part structure, indicated schematically.  
         [0020]     Unit carrier  24  is configured so that the secondary units, namely generator  26  and refrigerant compressor  28 , seen in the forward travel direction  16 , are arranged on the side, next to engine block  12 . In this connection, both generator  26  and refrigerant compressor  28  are arranged at a distance from engine block  12 , by means of the unit carrier  24 , so that a relative movement of generator  26  and refrigerant compressor  28 , relative to engine block  12 , is possible in case of a crash, as will be explained in more detail below. Unit carrier  24  is provided with two planned breakage points  38  that are merely indicated schematically in  FIG. 1 , by means of a notch. Planned breakage points  38  are arranged approximately at the level of the lateral delimitations of engine block  12 , seen in the forward travel direction  16 . As will be described below, unit carrier  24  can thereby shear off in the region of planned breakage points  38 , and generator  26  and/or refrigerant compressor  28  can be displaced opposite travel direction  16 , together with the broken piece of unit carrier  24  that is attached to them.  
         [0021]     Unit carrier  24  is furthermore configured so that seen in forward travel direction  16 , a front delimitation of the secondary units, namely generator  26  and refrigerant compressor  28 , is located in front, relative to a front delimitation of engine block  12 . A front delimitation of generator  26  or refrigerant compressor  28  is formed by a pulley, in each instance, by way of which drive belt  30  runs and drives a shaft of generator  26  or refrigerant compressor  28 , in each instance. In the representation according to  FIG. 1 , the front delimitation of generator  26  and refrigerant compressor  28  is placed in front of engine block  12 , proceeding from the front delimitation of the latter, by approximately a quarter of its length, in the forward travel direction  16 . In this connection, the forward placement is chosen to be so great that a noteworthy dissipation of energy can already take place by means of unit carrier  24  deforming or shearing off in case of a collision. Because of the energy dissipation by unit carrier  24 , the surrounding car body parts can therefore be relieved of stress in case of a collision, and can be made lighter, if necessary.  
         [0022]     The schematic representation of  FIG. 2  shows the internal combustion engine  10  of  FIG. 1  after a vehicle collision. Here, the front part structure  36  has been displaced by a deformation path A opposite forward travel direction  16 . The original position of front part structure  36  and radiator  34  is indicated by dot-dash lines in  FIG. 2 .  
         [0023]     As a result of the displacement of front part structure  36  by deformation path A, engine block  12  has also been displaced towards the vehicle interior, by a (smaller) distance. This can be seen, for example, by the position of the motor bearings  14  relative to the fixed bearing points  15  on the car body, which has been displaced towards the rear in  FIG. 2 , as well as by the position of engine block  12 , clutch bell  18 , and transmission  20 , which position has been displaced relative to contour  22  of the water tank.  
         [0024]     In  FIG. 2 , unit carrier  24  has sheared off in the region of its two planned breakage points  38 , so that both generator  26  and refrigerant compressor  28  were able to be displaced, seen opposite the forward travel direction  16 . In this connection, both generator  26  and refrigerant compressor  28  have not only been displaced opposite forward travel direction  16 , but have also performed a rotational movement, approximately about the center of unit carrier  24 . In  FIG. 2 , generator  26  and refrigerant compressor  28  are now only connected with engine block  12  by way of drive belt  30 . Guidance of drive belt  30  on generator  26  and refrigerant compressor  28 , respectively, can be implemented in such a way that generator  26  and refrigerant compressor  28 , respectively, with the broken piece of unit carrier  24  attached to them, are prevented from flying around. As an alternative, unit carrier  24  can be configured so that instead of a planned breakage point, a planned deformation point is provided, and even after a vehicle collision, the secondary units are securely held on engine block  12 , by means of unit carrier  24 , which is then deformed.  
         [0025]     In total, it is evident from  FIGS. 1 and 2  that because of the forward placement of generator  26  and refrigerant compressor  28 , relative to engine block  12 , the internal combustion engine  10  can already participate in a collision delay at an early point in time, and that energy dissipation by means of deformation of unit carrier  24  can already take place at an early point in time during the collision, because the secondary units are placed in front and because planned breakage points  38  are provided on unit carrier  24 . Furthermore, by providing planned breakage points  38  on unit carrier  24 , block formation of engine block  12  and generator  26  as well as the refrigerant compressor  28  is avoided, so that compared with the total deformation path A, a relatively low penetration depth of internal combustion engine  10  in the direction of the vehicle interior occurs.  
         [0026]     Accordingly, while only a few embodiments of the present invention have been shown and described, it is obvious that many changes and modifications may be made thereunto without departing from the spirit and scope of the invention.