Abstract:
An improved an accessory mounting arrangement for an internal combustion engine that allows a low mounting position without overstressing the oil pan that provides a part of the support.

Description:
BACKGROUND OF INVENTION  
         [0001]    This invention is adapted to be embodied in an internal combustion engine and more particularly to a mounting arrangement for an accessory that is driven by an output shaft of the engine at a relatively low position but is quite secure and does not overstress any engine component.  
           [0002]    As is well known, internal combustion engines are particularly utilized to drive a number of accessories, many of which are not essential for the operation of the engine.  
           [0003]    This is particularly true with vehicle applications where the many of the engine driven accessories serve functions for other vehicle systems such as air conditioning, electrical power generation and power assisting vehicle components other than the engine.  
           [0004]    This basically presents problems in both accessory positioning, serviceability, accessory drive and the like. It has therefore been the practice to locate at least some of these accessories quite low and often below the rotational axis of the engine output shaft. An example of such a mounting relation is shown in Japanese Published Application Hei 6-108919. As seen therein the engine has an engine body and support means for allowing an accessory for the engine to be disposed in the outer lateral vicinity of the engine body and to be supported on the engine body,. As is typical, the engine body includes a cylinder block in which cylinder bores are formed. Pistons reciprocate in these cylinder bores and drive the engine crankshaft. This crankshaft is journalled for rotation by the cylinder block and a bulkhead that is secured to the lower face of the cylinder block. Also an oil pan is secured to the lower face of the bulkhead for reserving the engine lubricating oil.  
           [0005]    As shown in this publication, the accessory is supported on the oil pan alone. This requires the oil pan sufficiently to support the accessory even though the oil pan is not originally designed for this purpose. However this may cause the configuration of the oil pan to be complicated and also requires the oil pan to be provided with a bulged portion which tends to make the engine oversized.  
           [0006]    It is therefore a principle object of the invention to provide an accessory mounting arrangement for an internal combustion engine that allows a low mounting position without overstressing the oil pan that provides a part of the support.  
         SUMMARY OF INVENTION  
         [0007]    This invention is adapted to be embodied in an accessory drive and support for an internal combustion engine that is comprised of an engine body consisting of a cylinder block having at least one cylinder bore, a cylinder head affixed to the cylinder block in closing relation to the cylinder bore and a crankcase assembly affixed to a portion of the cylinder block in spaced relation to the cylinder head. The crankcase assembly includes an oil pan for collecting lubricating oil from the engine. A crankshaft is journalled for rotation about an axis between the cylinder block and the crankcase assembly. The crankshaft is driven by a piston reciprocating in the cylinder bore. The engine accessory has a shaft driven from the crankshaft and is supported directly by the oil pan and by another component of the engine body that is disposed on the other side of the crankshaft axis from the oil pan. 
       
    
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0008]    [0008]FIG. 1 is a front elevational view of an internal combustion engine and accessory drive constructed in accordance with an embodiment of the invention.  
         [0009]    [0009]FIG. 2 is an enlarged front elevational view of the engine looking in the same direction as FIG. 1, but with the timing cover of the engine removed.  
         [0010]    [0010]FIG. 3 is a side elevational view of the engine.  
         [0011]    [0011]FIG. 4 is a side elevational view looking in the same direction as FIG. 3, showing only the assembled cylinder block and crankcase assembly in solid lines and some of the engine accessories in phantom. 
     
    
     DETAILED DESCRIPTION  
       [0012]    Referring now in detail to the drawings, a multi-cylinder, four-stroke internal combustion engine embodying the invention is indicated generally by the reference numeral  11 . In the illustrated embodiment the engine  11  is shown as having four in line cylinders. Of course, from the following description it will be obvious to those skilled in the art, that the invention can be utilized with engines having other numbers of cylinders and other engine configurations. In addition the invention is not limited to engines operating on the four stroke principle.  
         [0013]    The engine  11  is adapted to be mounted on and power a vehicle such as an automobile and is depicted as being mounted vertically therein, although the invention is not so limited. The engine  11  has an engine body, indicated generally at  12  supported in a suitable fashion by a vehicle body (not shown). engine body  12  is comprised of a cylinder block, indicated generally at  13 . The cylinder block  13  is formed with four cylinder bores  14  having parallel axes  15 . Detachably affixed, in a known manner, to the lower end of the cylinder block  13  is a bulkhead, indicated generally at  16 , to form the upper portion of a crankcase assembly.  
         [0014]    A cylinder head assembly  17  is secured to the upper face of the cylinder block  13  in a known manner and closed the upper ends of the cylinder bores  14 . The cylinder head assembly  17  supports valves for controlling the admission of a charge into the engine combustion chambers and the discharge of exhaust gasses therefrom in any suitable manner and as is well known in this art. These valves are operated in a manner to be described. This valve and operating mechanism is enclosed by a cylinder head cover  18  that is secured to the upper face of the cylinder head  17 .  
         [0015]    The aforedescribed crankcase assembly, the upper portion of which is formed by the lower part of the cylinder block  13  and bulkhead  16  is completed and closed by an oil pan, indicated generally at  19 , that is suitably secured to the lower face of the bulkhead  16  and contains lubricating oil.  
         [0016]    The engine  11  is provided with pistons  21  reciprocating in the cylinder bores  14  and connected by connecting rods  22  to drive a crankshaft  23 . The crankshaft  23  rotates about an axis  24  that extends generally horizontally. The crankshaft  23  is journalled about this axis  24  by bearings carried by the cylinder block  13  and bulkhead  16  in a manner well known in the art.  
         [0017]    The aforementioned intake and exhaust valves are operated in a suitable manner by a valve actuating mechanism, indicated generally at  25 . This valve actuating mechanism  25  is comprised of an intake camshaft  26  and an exhaust camshaft  27  in suitable operational engagement with the intake valves and exhaust valves, (not shown) respectively. The camshafts  26  and  27  haves axes that extend parallel to the axis  24  of the crankshaft  23 . A timing chain  28  interconnects a sprocket provided on one end of the crankshaft  23  with sprockets on the ends of the camshafts  26  and  27  to drive them in timed relation at one half the rotational speed thereof.  
         [0018]    As has been noted, the cylinder block  13  is made by casting, and preferably of low pressure cast aluminum. The cylinder block  13  generally comprises a cylinder block body, indicated generally at  29 , having a generally cubic shape and in which the plurality of cylinder bores  24  are formed. The body portion  29  has a pair of upper outwardly extending sides  31  defining at their top an upper face  32  that is in suitable sealing contact with the lower face of the cylinder head  17 . In a like manner, the sides of body portion  29  has outwardly extending sides  33  that form part of a lower face  34  that is in suitable sealing contact with the upper face of the bulkhead  16 . The oil pan  19  has a generally dish-shaped oil pan body  35  opening upward and an outward flange  36  formed integrally with the upper outer edge of the oil pan body  35  that is sealingly engaged with the lower face of the bulkhead  16  to add to the rigidity of the structure.  
         [0019]    The engine  11  is provided with a number of accessories disposed in the outer lateral vicinity of the engine body  12 , and support means supporting the accessories on the engine body  12 . Some of these accessories are for engine operation while others are for vehicle or other purposes. These include an air compressor  37  for vehicle air conditioning, an engine coolant pump  38  for delivering coolant to a coolant jacket formed in the engine body  12  to cool the engine body  12 , an alternator  39  for generating electrical power for the vehicle and engine ignition, and a power steering pump  41  for power assist of the vehicle steering. Each of these accessories  37 ,  38 ,  39  and  41  has a respective driven input shaft  42 ,  43 ,  44  and  45  that have their rotational axes extending parallel with the axis  24  of the crankshaft  23 . Respective drive pulleys  46 ,  47 ,  48  and  53  are affixed respectively to the accessory driven input shafts  42 ,  43 ,  44  and  45 . These pulleys are all driven from a pulley  51  that is affixed to the crankshaft  23  by means of a serpentine belt  52 .  
         [0020]    The air compressor  37  is provided has a compressor body  53  in which the input shaft  42  is journalled in any known manner. Upper and lower brackets  54  and  55  protrude integrally from the compressor body  53 . The upper bracket  55  cooperates in a manner to be described with an upper support portion  56  integrally protruding laterally outward from the lower end of the cylinder block  13 . In addition, a lower support portion  57  integrally protruding laterally outward from the upper end of the oil pan  19  that cooperates with the lower bracket  55 . A first pair of fasteners  58  fasten the upper bracket  54  to the upper support portion  56 , and a second pair of fasteners  59  fastening the lower bracket  55  to the lower support portion  57 .  
         [0021]    Thus the air compressor  37  is supported by both ends being secured to the cylinder block  13  and the oil pan  19  and spanning the bulkhead  16 . Nevertheless the compressor body  53  is positioned in the outer lateral area of a vertical area of the bulkhead  16 . In addition, at least part of the upper support portion  56  is formed integrally with the lower outer flange  27  of the cylinder block  13  for reinforcement. Also, at least part of the lower support portion  57  is formed integrally with the outer flange  36  of the oil pan  19  for reinforcement. Specifically, the part of the compressor body  53  defining the axis  44  of the input shaft  43 , protrudes forward from the bulkhead  16  to a greater extent than the upper and lower brackets  54 ,  55 .  
         [0022]    Because the compressor  36  is supported on the engine body  12 , the external force applied by the compressor  36  is not only shared by the cylinder block  13  and the oil pan  19 , but also shared indirectly by the bulkhead  16 , which is overlain by the compressor  36 . Therefore, the support strength of the compressor  36  on the engine body  12  can be more securely improved.  
         [0023]    The engine coolant pump  38  is provided with a casing  61  that forms its outer shell. This is disposed in the outer lateral area of the cylinder block  13  on the same side as the air compressor  37 . This casing  61  is formed integrally with the outer lateral face of the cylinder block  13  and thus reinforces it. At least part of the lower end of the casing  61  is formed integrally with the upper support portion  56 , that is, the upper portion of the air compressor  37  is supported on the cylinder block  13  in the vicinity of the casing  61 .  
         [0024]    Therefore and as described above, the support of the compressor  37  on the engine body  12  is effectively improved by supporting the compressor  37  on both the lower end of the cylinder block  13  and the upper end of the oil pan  19 . Since at least part of the compressor body  53  is positioned in the outer lateral area of the midsection of the bulkhead  16  in the vertical direction, the part of the compressor body  53  can be disposed closer to the crankshaft  23  without obstruction by the outward flanges  36  and/or with the use of the recess in the bulkhead  16  so that the compressor  37  can be arranged in a compact manner, thereby preventing the engine  11  from being oversized. Furthermore, since the compressor  37  can be positioned closer to the crankshaft  23 , the configuration of the drive belt  52  interconnecting the compressor  37  and the crankshaft  23  can be shorter.  
         [0025]    Of course those skilled in the art will readily understand that the described embodiment is only exemplary of forms that the invention may take and that various changes and modifications may be made without departing from the spirit and scope of the invention, as defined by the appended claims. For examples only, the engine  21  may be a two-stroke engine and/or the axes  25  of the cylinder bores  24  may be inclined with respect to the vertical. Also the compressor  37  may be driven from another power source than the engine  11  itself.