Patent Publication Number: US-6904887-B2

Title: Engine accessory drive system

Description:
BACKGROUND OF INVENTION 
   This invention relates to an engine accessory drive system and more particularly to an improved arrangement for mounting a component of the accessory on a light weight casting of the engine body without requiring special reinforcing in the mounting assembly. 
   Frequently an engine accessory is mounted on a light weight casting of an engine body to provide a convenient mounting relationship. For example it has been proposed to mount an oil pump for the engine on an alloy bulkhead member that cooperates with the alloy cylinder block to journal the engine crankshaft. Generally this type of arrangement provides a flexible transmitter drive for driving the oil pump from the engine crankshaft. This type of drive normally requires a tensioner mechanism for maintaining the proper tension in the transmitter. These tensioners are spring biased and the spring loading places a high stress on the alloy casting that might cause problems. An example of this type of construction is shown in Japanese published application, publication number Hei 6-299863. This requires reinforcing of the alloy casting, which adds to the expense. 
   In the aforenoted crankshaft journaling arrangements it has been proposed to embody ferrous reinforcements in at least one of the alloy castings to reinforce the casting in the area where the crankshaft is journalled. Examples of such reinforcing may be seen in U.S. Pat. Nos. 4,693,216 and 5,769,546. However the use of these reinforcements has been limited to the journaling of the crankshaft. 
   It is therefore a principle object of this invention to provide an improved and simplified reinforcement for the mounting of an engine driven assembly component on a light alloy casting thereof. 
   It is a further object of the invention to utilize a reinforcing member in a light alloy casting provided for another purpose, for the mounting of the engine driven assembly component. 
   SUMMARY OF INVENTION 
   This invention is adapted to be embodied in an internal combustion engine and bearing arrangement for an engine driven accessory. The engine has a driven shaft journalled by a pair of mating light alloy castings. A reinforcing element formed from a stronger material than the casting is embedded in one of the mating castings. In accordance with the invention, a component of the engine driven accessory is supported directly by the reinforcing element. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
       FIG. 1  is a front elevational view of an internal combustion engine and accessory drive constructed in accordance with an embodiment of the invention. 
       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. 
       FIG. 3  is a side elevational view of the engine. 
       FIG. 4  is an enlarged cross sectional taken along the line  4 — 4  in FIG.  2 . 
       FIG. 5  is a further enlarged view, in part similar to  FIG. 4 , but shows the tensioner arm in solid lines and is taken along the line  5 — 5  of  FIG. 6   FIG. 6  is a front elevational view of the structure shown in FIG.  5 . with the tensioner and crankshafts being shown in section. 
       FIG. 7  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. 
       FIG. 8  is an enlarged view looking in the same direction as  FIG. 1 , of the oil filter and mounting arrangement therefore with portions broken away and shown in section. 
   

   DETAILED DESCRIPTION 
   Referring now in detail to the drawings and initially primarily to  FIGS. 1-3 , 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. 
   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). The engine body  12  is comprised of a cylinder block, indicated generally at  13 . The cylinder block  13  is formed with four cylinder bores  14  ( FIG. 2 ) 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. 
   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 . 
   The aforementioned 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. 
   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 as will be described. 
   The previously mentioned intake and exhaust valves (not shown) 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, 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 , to be described later, with sprockets on the ends of the camshafts  26  and  27  to drive them in timed relation at one half the rotational speed thereof. 
   As has been noted, the cylinder block  13  is made by casting, and preferably of low pressure cast aluminum with the cylinder head  17  formed of the same material and fixed to the upper face thereof in a known manner. The aforedescribed crankcase assembly and specifically an upper flange  29  of the bulkhead  16  is affixed thereto in any suitable manner. The oil pan  19  has a generally dish-shaped oil pan body  31  opening upward and an outward flange  32  formed integrally with the upper outer edge of the oil pan body  31  that is sealingly engaged with the lower face of the bulkhead  16  to add to the rigidity of the structure. 
   The engine  11  is provided with a number of accessories disposed in the outer lateral vicinity of the engine body  12 . Some of these accessories are for engine operation while others are for vehicle or other purposes. These include an air conditioning compressor  33  for vehicle air conditioning, an engine coolant pump  34  for delivering coolant to a coolant jacket formed in the engine body  12  to cool the engine body  12 , an alternator  35  for generating electrical power for the vehicle and engine ignition, and a power steering pump  36  for power assist of the vehicle steering. Each of these accessories  33 ,  34 ,  35  and  36  are driven in a well known manner from a pulley  37  that is affixed to the crankshaft  23  by means of a serpentine belt  38 . 
   As has been noted, the engine driven accessories include the coolant pump  34 . This pump  34  has an outer housing that is integral with the cylinder block  13  and thus reinforces it. This outer housing includes a discharge duct portion  39  that communicates with cooling jackets  41  ( FIG. 2 ) formed in the cylinder block  13  around the cylinder bores  14 . These cooling jackets  41  also cooperate with cooling jackets (not shown) formed in the cylinder head  17 . The coolant also passes through a heat exchanger (not shown) in a manner well known in the art. 
   In addition to the cooling system just described and in accordance with the invention, the engine  11  is provided with a lubricating system that includes the crankcase assembly and specifically the oil pan  19 . The lubricant is supplied by this system to portions of the engine  11  to be lubricated such as bearings for the crankshaft  23  and the camshafts  26 ,  27 . The lubricating system is provided with an oil pump  42  supported directly on the bulkhead  16  so that it protrudes downward from the lower face of the bulkhead  16  to be disposed in the oil pan  19 . 
   The oil pump  42  may be of any known type and has a drive shaft  43  to which a sprocket  44  affixed to an end thereof that extends outwardly in the oil pan  19 . The sprocket  44  is driven by a driving chain  45  that is driven in turn by a sprocket  46  fixed to one end of the crankshaft  23 . This drive will now be described in more detail by primary reference to  FIGS. 4-6 . There is provided a tensioner mechanism, indicated generally by the reference numeral  47 , for maintaining the desired tension in the oil pump driving chain  45 . 
   The tensioner  47  is includes a tension arm  48 , one end of which is pivoted on the bulkhead  16  by a pivot shaft  49  so that the other end can be rotated about an axis  51  defined by the pivot shaft  49 . The other end of the arm  48  is urged into contact with the chain  45  by a spring, indicated generally at  52 , to maintain the desired tension. tensioner mechanism  47  is supported in a manner that embodies the invention and which will be described in detail by continued reference to  FIGS. 4-6 . 
   In order to reinforce the bearing support for the crankshaft  23  in the bulkhead  16 , the webs of the bulkhead  16  that journal the crankshaft  23  and particularly the forward most end web, a cast iron reinforcement  53  is embedded in the bulkhead body web  54  by insert molding in casting the bulkhead  16  for reinforcing a bearing part for the crankshaft  16 . In the illustrated embodiment, the reinforcement  53  actually carries the bearing for the crankshaft  23 . To this end, the reinforcement  53  is provided with an arcuate reinforcement portion  55  extending in the circumferential direction of the crankshaft  23  along its lower face for supporting the lower half of the crankshaft  23 . A support portion  56  protrudes integrally downward from the reinforcement portion  55  and is embedded in the bulkhead web  54  to support the reinforcement portion  55 . An integral boss  57  protrudes radially outward from the side of reinforcement body  55  adjacent the tensioner  47 . 
   The tensioner arm  48  is pivotally supported by the reinforcement  55  and particularly by its boss  57 . Specifically, a female threaded hole  58  is formed in the boss  57  of the reinforcement  55  on the axis  51 . A male threaded end of the pivot shaft  52  is threaded into the female threaded hole  58 , whereby the pivot shaft  52  is supported on the boss  57  to journal the tensioner arm  48 . 
   The side of the bulkhead web  54  facing the cylinder block  13  is formed with a groove  59  extending in the axial direction in the vicinity of the tensioner  47 . The groove  59  is open at the forward end and closed at its rearward end. One end  61  of the spring  52  is fitted into the open end of the groove  59 . The spring  52  has another end  62  that is engaged with the tension arm  48  so as to urge the tension arm  48  into pressure contact with the chain  45  to maintain the desired tension in the chain  45 . 
   Referring now back to the remaining figures of the drawings and particularly initially to  FIGS. 3 ,  7  and  8 , the oil pump  42  supplies its pumped lubricant to the lubricated components of the engine  11  through a feed system that includes a removable oil filter of the cartridge type, indicated generally by the reference numeral  63 . This is mounted on the engine  11  and particularly on the bulkhead  16  by a mounting bracket, indicated generally at  64  as shown best in FIG.  8 . This mounting bracket  64  is affixed, in a manner to be described shortly, on a mounting pad  65  formed integrally on a side face of the bulkhead  16 . 
   In addition to carrying the oil filter  63 , the mounting bracket  64  carries an oil cooler, indicated generally by the reference numeral  66 . This oil cooler  66  is interposed, in a manner to be described shortly, between the mounting bracket  64  and the oil filter  63 . Referring now additionally to  FIG. 7 , it will be seen that the mounting pad  65  is formed as an outward projection of the side face of the bulkhead  16  and defines an inlet cavity  67  and a discharge cavity  68  that are separated by an angularly disposed dividing wall  69 . 
   Continuing to refer primarily to  FIGS. 7 and 8 , it will be seen that the oil pump  42  discharges the pumped oil in a vertical direction to enter a vertically extending passage  71  that extends in the bulkhead  16  from its lower face. This vertical passage  71  intersects a horizontal passage  72  that terminates in the inlet cavity  67  of the mounting pad  65  via an opening  73 . 
   After passing through the oil cooler  66  and the filter  63 , in a manner to be described shortly, the cooled and filtered lubricant is delivered to the discharge cavity  68  for delivery to the lubricated components of the engine  11  through an opening  74  of the main oil gallery of the engine  11  that is formed initially in the bulkhead  16 . The opening  74  communicates with the initial part of the main oil gallery, indicated by the reference numeral  75 , that is formed in the bulkhead  16  as seen in FIG.  8 . From there the oil passes to the aforenoted lubricated components of the engine through suitable passages, as is well known in the art. 
   Continuing to refer primarily to  FIG. 8 , it will be seen that the mounting bracket  64  which is formed separately from the bulkhead  16  has a pair of side flanges  76  that have openings for receiving fasteners  77  for removable attachment to the mounting pad  65  formed on the outer lateral face of the bulkhead  16 . 
   The oil cooler  66  has an outer housing  78  of a generally ring shape with a generally flat upper surface  79  that is held in sealing relation with a mating lower surface of the mounting bracket  64  by means of a shoulder  81  of a fastener, indicated generally by the reference numeral  82 . The fastener  82  has a threaded portion  83  that is received in a tapped opening of the mounting bracket  64  to load a sealing gasket  84  between the mating face  79  of the oil cooler  66  and the mounting bracket  64 . 
   Positioned within the oil cooler body  78  is a heat exchanger  85  that receives engine coolant from the engine cooling jacket  41  via a conduit  86  and fitting  87  (FIG.  3 ). After this coolant passes through the heat exchanger  75  it is returned to the cooling jacket  41  via a return fitting  88  and return conduit  89 . 
   Referring again to  FIG. 8 , the oil filter  63 , as has already been noted, is of the canister type and includes a can shaped outer housing  91  in which a filter media of any desired type  92  is received. This outer housing is formed with an end wall  93  having a tapped opening  94  that is threaded onto a lower threaded portion  95  of the fastener  82 . A sealing ring  96  is thus sealingly compressed between the end wall  93  and the lower face of the heat exchanger body  78 . 
   The cylinder block oil passage  72  mates with an oil delivery passage  97  formed in the mounting bracket  64  that terminates in a plurality of downwardly opening passages to communicate with the upper wall of the oil cooler  66  in the area inwardly of the sealing gasket  84 . The oil cooler outer housing has a plurality of openings  98  in this area to permit oil to enter into the oil cooler  66  for cooling in the direction indicated by the arrows. 
   In a like manner the lower wall of the oil cooler housing  78  has a plurality of discharge openings to permit the oil to enter the area of the oil filter end wall  83  inwardly of the sealing ring  86  again as shown by the flow indicating arrows. The oil then enters the oil filter  63  to flow through the filter media  82  through openings in the end wall  93  as also shown by the flow indicating arrows. 
   The thus cooled and filtered oil then exits the filter  63  and cooler  66  through an internal passage  99  formed in the fastener  82 . The oil then flows into a delivery passage  101  formed in the mounting bracket  64 , as again shown by the flow arrows. The delivery passage  9101  in turn communicates with the initial part  75  of the engine main oil gallery formed in the bulkhead  16  to deliver the cooled and filtered oil to the engine  11 . After the lubrication, the lubricating oil is returned to the oil pan  19  in any known manner for repeated delivery by the oil pump  42 . 
   In the above case, the oil filter  63  and the oil cooler  66  are both located on an axis defined by the fastener  82 . The lubricating oil flows in an axial direction evenly through the oil filter  63  and the oil cooler  66 , and returns through the passage  89  in the fastener  82 . Thus, the filtration of the lubricating oil by the oil filter  63  and the cooling by the oil cooler  66  can be achieved effectively. 
   Since all of the oil delivery passages and return passages between the oil pump  42 , the oil cooler  66 , oil filter  63  and the engine lubricating main gallery  75  are formed in a single engine body piece, in this case the bulkhead  16 , the number and location of sealing surfaces required by the prior art constructions is substantially reduced with not only cost savings but good insurance against leakage. Also, since the bracket  64  is a separate body from the bulkhead  16 , it is possible to select a variety of postures and positions of the oil filter  63  and the oil cooler  66 , which are secured to the bracket  64 , by selecting a variety of shapes of the bracket  64 . Therefore, adoption of suitable postures and positions of the oil filter  63  and the oil cooler  66  permits arranging the engine body  12 , the oil filter  63 , and the oil cooler  66  in a compact manner, thereby preventing the lubricating system from being oversized. 
   From the foregoing description it should be readily apparent to those skilled in the art that the described construction is highly effective in providing a strong mounting attachment for an engine accessory component on a light weight element of an engine body. 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  11  may be a two-stroke engine and/or the axes  15  of the cylinder bores  14  may be inclined with respect to the vertical.