Abstract:
The invention aims at providing a compact mounting arrangement for an automobile drive unit consisting of a combustion engine and a transmission. According to the invention, the crankshaft of the combustion engine and an auxiliary shaft driven by said crankshaft extend in the longitudinal direction of the vehicle, the cylinders of the combustion engine are subdivided into at least two rows forming an angle in relation to each other, wherein one of said cylinder rows is disposed in a horizontal or substantially horizontal manner.

Description:
This is a U.S. national stage of application No. PCT/EP99/02716, filed on Apr. 22, 1999. Priority is claimed on that application and on the following application: 
   Country: Germany, Application No.: 198 43 258.5, filed Sep. 21, 1998. 

   BACKGROUND OF THE INVENTION 
   The invention relates to an installation arrangement for a drive unit which is intended for a vehicle and has an internal combustion engine and a transmission. 
   EP 0411319 A2, which represents the prior art in this field, discloses a motor vehicle having an inline internal combustion engine, having a crankshaft mounted in a housing of the internal combustion engine and having a parallel auxiliary shaft which is driven by this crankshaft and is used to transmit power to the transmission. The arrangement is in this case designed such that the internal combustion engine, which is in the form of a reciprocating piston internal combustion engine, is installed in the nose of the vehicle transversely between the driven front wheels and with one cylinder row inclined to the rear and with the auxiliary shaft, located in front of the internal combustion engine, being driven via a gear train arranged at the end of the internal combustion engine. This auxiliary shaft transmits the power directly from the internal combustion engine to a transmission, with a transmission output drive shaft that is located behind the internal combustion engine in the direction of travel driving the input drive shaft associated with the front wheels via a branch. 
   DE 39 206 38 C2 discloses a drive system for a motor vehicle having an inline internal combustion engine fitted in the longitudinal direction, in which a longitudinally fitted transmission is arranged behind the internal combustion engine in the direction of travel, is driven directly by the crankshaft, and whose output drive shaft, which runs at the side alongside the internal combustion engine, drives a branch, which is in the form of a differential, in a housing formed separately on an oil sump. An intermediate shaft which passes through the internal combustion engine oil sump runs between this differential and the vehicle wheel located on the other side of the internal combustion engine. 
   In order to reduce the installed height of this drive system, the cylinder row is fitted so that it is inclined to the right when seen in the direction of travel, so that the differential, when seen from above, is arranged lying underneath the cylinder row. 
   Finally, for an internal combustion engine having a V-shaped cylinder arrangement that is symmetrical with respect to a vertical plane and having a longitudinal crankshaft, it is known from EP 0514943 B1 for an arrangement which shortens the installation space of the drive unit comprising the internal combustion engine and the transmission, for the differential (which is driven by the output drive shaft of the transmission which is routed at the side alongside the internal combustion engine) to be arranged lying well forward in the direction of travel, at the side alongside the internal combustion engine. 
   SUMMARY OF THE INVENTION 
   The invention is based on the object of providing an installation arrangement of this generic type for a drive unit having an internal combustion engine and a transmission in a vehicle, which, with an arrangement that saves installation space, allows a comparatively large number of cylinders and allows a small vehicle overhang in front of the vehicle wheels. 
   Pursuant to this object, and others which will become apparent hereafter, one aspect of the present invention resides in an installation arrangement for a vehicle drive unit, which installation arrangement includes an internal combustion engine having cylinders arranged in at least two cylinder rows at an angle to one another. One of the cylinder rows is arranged to lie at least substantially horizontally. The installation arrangement further includes a transmission, an engine housing and a crankshaft mounted in the engine housing so as to lie in a longitudinal direction of the engine. A parallel auxiliary shaft is driven by the crankshaft for transmitting power to the transmission and an output drive shaft is in operative connection with the transmission for driving wheels of the vehicle. 
   In contrast to the prior art in this generic field, the invention provides for the crankshaft to be arranged such that it runs in the longitudinal direction of the vehicle, and for the cylinders of the internal combustion engine to be arranged in at least two cylinder rows that are at an angle to one another, with one of these cylinder rows being arranged horizontally or essentially horizontally. The term “at an angle” in this case means an angle of 90 degrees +/− 45 degrees, but not an angle in the order of magnitude of 180 degrees, as is used for Boxer internal combustion engines and their arrangement, which occupies a large amount of space, at least in width. 
   The output drive power from the crankshaft is not emitted directly from the crankshaft to the transmission, but via the auxiliary shaft to the transmission, which is generally arranged centrally in the vehicle, thus allowing the crankshaft to be moved to the side away from this vehicle center, which in turn enlarges the installation space on the opposite side, and this is filled by the horizontal cylinder row. The second cylinder row, which is arranged at an angle to this horizontal cylinder row, may be vertical, but can also be arranged such that it is swiveled laterally to one side or the other from the vehicle longitudinal center plane in order to reduce the installation height further. 
   In one preferred refinement, the installation space can be further optimized by arranging the auxiliary shaft to run in the vehicle center plane rather than the crankshaft, with a separation plane, which is provided in the housing of the internal combustion engine and bears the auxiliary shaft and the crankshaft, being positioned obliquely, that is to say being arranged inclined to a vertical. 
   Further advantages and features of the invention will become evident from the exemplary embodiment which is explained in more detail in the following text with reference to a drawing. 
   Where this disclosure refers to a lying or horizontal arrangement of the cylinder row, then this does not necessarily mean an exactly horizontally lying cylinder row and a minor deviation of the cylinder row position in both directions is, in fact, feasible without departing from the advantages according to the invention. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In the figures: 
     FIG.  1 : shows a schematic side view of an installation arrangement; 
     FIG.  2 : shows a plan view thereof; 
     FIG.  3 : shows a schematic view from the front; 
     FIG.  4 : shows a view from the rear of the internal combustion engine only; 
     FIG.  5 : shows a view from the right with respect to  FIG. 4 ; 
     FIG.  6 : shows a view from the front of the internal combustion engine only; and 
     FIG.  7 : shows a view from the right with respect to FIG.  6 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   A vehicle, of which only the front vehicle area is illustrated schematically in  FIG. 1 , has a drive unit comprising an internal combustion engine  2  and a transmission  4 . The drive unit is fitted in the longitudinal direction L of the vehicle, which corresponds to a direction of travel F. Seen clockwise in the direction of travel F, the internal combustion engine  2  has a total of three cylinder rows  6 ,  8 ,  10  which each have six cylinders, with the first cylinder row  6  arranged horizontally, and a second cylinder row  8  and a third cylinder row  10  each being arranged at an angle to the first cylinder row  6  such that the second cylinder row  8  is arranged on the angle bisector between the first and third cylinder rows  6  and  10 . 
   The second and third cylinder rows  8  and  10  are provided symmetrically, in the manner of a V-arrangement, with respect to a vertically running crankshaft plane KE which accommodates a crankshaft  12 . 
   The housing (which is designated  14  overall) of the internal combustion engine  2  is formed essentially from three relatively large components, a crankshaft housing upper part  16  which carries the three cylinder rows  6 ,  8 ,  10 , a bearing traverse  18  mounted adjacent thereto, and a housing lower part  20 , which is in turn adjacent to the bearing traverse  18 . The crank housing upper part  16  and the bearing traverse  18  are adjacent to one another in a separation plane TE 1 , in which the crankshaft  12  and an auxiliary shaft  22  driven by it are mounted such that they can rotate. 
   A second separation plane TE 2  runs parallel to the first separation plane TE 1  between the bearing traverse  18  and the housing lower part  20 ; the two separation planes TE 1 , TE 2  are arranged inclined through an angle W with respect to the crankshaft plane KE and the auxiliary shaft plane NE. 
   The auxiliary shaft  22  runs in the auxiliary shaft plane NE which is arranged parallel to and at a distance A from the crankshaft plane KE and is identical to a vehicle longitudinal center plane. 
   The auxiliary shaft  22  is driven in a manner which is not shown within the housing  14  by the crankshaft  12 , and is used to transmit power to the transmission  4 . Located at the rear in the direction of travel F, the transmission  4  has a distributor transmission  24  which, in a manner which will be explained further below, optionally drives rear wheels of the vehicle via an output drive and, via an output drive shaft  26  routed at the front, and in a manner which is still to be described, drives steerable wheels  28  and  30  which are arranged at the side alongside the drive unit. 
   Opening  34  which has a center point MP is provided on a rear wall  32  of the internal combustion engine  2 , located at the rear in the direction of travel F of the vehicle, on which opening  34  the output drive shaft  26  is articulated in a manner which is not shown in any more detail. 
   The crankshaft plane KE runs on a side S 1  of the auxiliary shaft plane NE that is on the right seen in the direction of travel F, while the center point MP is located to the right of this crankshaft plane KE, once again seen in the direction of travel F. 
   The output drive shaft  26 , which is connected to the opening  34 , runs rising in the direction of travel F from the distributor transmission  24  and, in the housing lower part  20 , drives a short shaft  36  which is mounted and supported there. This shaft  36  drives a branch  40 , which is in the form of a differential  38 . A pot-like depression  42  is arranged recessed integrally in the housing lower part  20  in order to accommodate this differential  38 . On the output drive side, an input drive shaft  44  which leads to the right-hand wheel  30  and an intermediate shaft  48 , which leads to an input drive shaft  46  for the left-hand wheel  28 , are arranged directly adjacent to the differential  38 , seen in the direction of travel F. This intermediate shaft  48  is mounted in the depression  42  at the differential end and its longitudinal axis D extends through a bearing neck  50 , formed integrally with the bearing traverse  18 , with its longitudinal axis D passing through the separation planes TE 1  and TE 2 . On the output side of this bearing neck  50 , the input drive shaft  46  is connected and transmits the drive power to the wheel  28 , with both input drive shafts  44 ,  46  being articulated in the region of the wheel axles  52 ,  54 . 
   In a plan view of the vehicle, both input drive shafts  44 ,  46  are positioned angled to the rear with respect to the direction of travel F, that is to say an angle α between the vehicle longitudinal center plane or the auxiliary shaft plane NE and the input drive shafts  44 ,  46  is less than 90 degrees. 
   In a view of the vehicle from the front, both input drive shafts  44 ,  46  are arranged so as to be inclined upward, that is to say with an angle β between the vehicle longitudinal outer plane or the auxiliary shaft plane NE and the input drive shafts  44 ,  46  that is less than 90 degrees. 
   As already mentioned initially in the description of the figures, the distributor transmission  24  may have a further output drive in the form of a universally jointed shaft  56 , which leads to a rear axle differential  58  from where it drives the rear wheels via universally jointed shafts  60 ,  62 . 
   A passage  72  for a steering linkage  74  is provided in the housing lower part  20  between the end wall  32  and the depression  42  for the differential  38 . This passage  72  is operated from a steering wheel  78  with the interposition of the steering column  76  and transmits the rotary movements from the steering wheel  78  by means of a track rods  80  to the driven wheels  28  and  30 . 
   The relationships are particularly space-saving and advantageous for installation if the angle W 13  between the first cylinder center plane ZME 1  and the third cylinder center plane ZME 3  is 120 degrees, as a consequence of which the cylinder center plane ZME 2 , which is arranged on the angle bisector, respectively forms an angle W 12  or W 23  of 60 degrees to the adjacent cylinder center planes ZME 1  and ZME 3 . Values of between 25 degrees and 35 degrees are advantageous in terms of installation space for the angle W, preferably between 30 and 35 degrees, and in particular 33 degrees. W 13  is 120 degrees, as a consequence of which the cylinder center plane  2 , which is arranged on the angle bisector, respectively forms an angle W 12  or W 23  of 60 degrees to the adjacent cylinder center planes ZME 1  and ZME 3 . Values of between 25 degrees and 35 degrees are advantageous in terms of installation space for the angle W, preferably between 30 and 35 degrees, and in particular 33 degrees. 
   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.