Patent Publication Number: US-8534251-B2

Title: Engine assembly with camshaft housing

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 61/345,380, filed on May 17, 2010. The entire disclosure of the above application is incorporated herein by reference. 
    
    
     FIELD 
     The present disclosure relates to engine assemblies, and more specifically to an engine assembly that includes a camshaft housing. 
     BACKGROUND 
     This section provides background information related to the present disclosure which is not necessarily prior art. 
     An engine assembly may include an engine structure that rotationally supports a camshaft assembly. The camshaft assembly may include a plurality of lobes and bearing regions located on the exterior surface of a hollow tube. During operation of the engine, the camshaft assembly is rotated and the lobes act to open the intake and/or exhaust valves of the engine. The bearing regions provide the bearing surface for the support of the camshaft assembly. The engine structure may provide one bearing support surface for the bearing regions of the camshaft assembly. A plurality of bearing caps or a camshaft housing may be coupled with the engine structure and provide a second bearing support surface for the bearing regions of the camshaft assembly. 
     SUMMARY 
     This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. 
     An engine assembly may include an engine structure, a first camshaft housing assembly and a first camshaft assembly. The first camshaft housing assembly may be supported by the engine structure and have a first portion providing a first plurality of bearing support surfaces on a first side and a second portion coupled to the first portion and providing a second plurality of bearing support surfaces on a second side opposite the first side. The first camshaft assembly may be rotationally supported by the first camshaft housing assembly and arranged between the first portion and second portion. 
     A method of assembling an engine assembly may include providing a first camshaft housing assembly having a first portion providing a first plurality of bearing support surfaces on a first side and a second portion coupled to the first portion and providing a second plurality of bearing support surfaces on a second side opposite the first side. The method may further include arranging a first camshaft assembly in the second portion such that the first camshaft assembly contacts the second plurality of bearing support surfaces. The first portion may be coupled with the second portion such that the first camshaft assembly is arranged between the first portion and second portion and the first camshaft assembly contacts the first plurality of bearing support surfaces. The first camshaft housing assembly with the first camshaft assembly arranged between the first portion and second portion may be coupled to an engine structure. 
     A central direct injection engine assembly may include an engine structure, an intake camshaft housing assembly, an intake camshaft assembly, an exhaust camshaft housing assembly and an exhaust camshaft assembly. The engine structure may include a cylinder head that defines an aperture. The intake camshaft housing assembly may be supported by the engine structure and have a first portion providing a first plurality of bearing support surfaces on a first side and a second portion coupled to the first portion with a first plurality of fasteners and providing a second plurality of bearing support surfaces on a second side opposite the first side. The intake camshaft housing assembly may be coupled to the cylinder head by a second plurality of fasteners. The intake camshaft assembly may be rotationally supported by the intake camshaft housing assembly and arranged between the first portion and the second portion. The exhaust camshaft housing assembly may be supported by the engine structure and have a third portion providing a third plurality of bearing support surfaces on a third side and a fourth portion coupled to the third portion with a third plurality of fasteners and providing a fourth plurality of bearing support surfaces on a fourth side opposite the third side. The exhaust camshaft assembly may be rotationally supported by the exhaust camshaft housing assembly and arranged between the third portion and the fourth portion. The exhaust camshaft housing assembly may be coupled to the cylinder head by a fourth plurality of fasteners such that the aperture is arranged between the first camshaft housing assembly and the second camshaft housing assembly. 
     Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The drawings described herein are for illustrative purposes only and are not intended to limit the scope of the present disclosure in any way. 
         FIG. 1  is a schematic section view of an engine assembly according to the present disclosure; 
         FIG. 2  is a partial perspective view of the engine assembly of  FIG. 1 ; 
         FIG. 3  is a partial perspective view of a camshaft housing assembly of the engine assembly of  FIG. 1 ; 
         FIG. 4  is a partial perspective view of the camshaft housing assembly of  FIG. 3 ; and 
         FIG. 5  is a partial perspective view of the camshaft housing assembly of  FIG. 3 . 
     
    
    
     Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. 
     DETAILED DESCRIPTION 
     Examples of the present disclosure will now be described more fully with reference to the accompanying drawings. The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. 
     Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail. 
     When an element or layer is referred to as being “on,” “engaged to,” “connected to” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments. 
     With reference to  FIG. 1 , an engine assembly  20  may include an engine structure  30 , a crankshaft  32  rotationally supported by the engine structure  30 , one or more pistons  34  coupled to the crankshaft  32  and reciprocally displaceable between a top dead center position and a bottom dead center position, first and second camshaft housing assemblies (such as intake and exhaust camshaft housing assemblies  35 ,  37 ) supported on the engine structure  30 , first and second camshaft assemblies (such as intake and exhaust camshaft assemblies  36 ,  38 ) rotationally supported on the intake and exhaust camshaft housing assemblies  35 ,  37 , respectively, valve lift assemblies  44 , at least one intake valve  46 , and at least one exhaust valve  50 . The engine structure  30  may include an engine block  56  and cylinder head  54 . The engine block  56  may define cylinder bores  58 . The cylinder head  54  and the cylinder bores  58  in the engine block  56  may cooperate to define combustion chambers  60 . In the present non-limiting example, the engine assembly  20  is shown as a dual overhead camshaft engine with the engine structure  30  having the cylinder head  54  supporting the intake and exhaust camshaft housing assemblies  35 ,  37 . It is understood, however, that the present disclosure is not limited to overhead camshaft configurations. 
     Referring now to  FIGS. 2-5 , exemplary intake and exhaust camshaft housing assemblies  35 ,  37  are illustrated. The intake camshaft housing assembly  35  may include a first portion  100  coupled to a second portion  102 . The first portion  100  may provide a first plurality of bearing surfaces  101  on a first side to rotationally support the intake camshaft assembly  36 . The second portion  102  may provide a second plurality of bearing surfaces  103  to rotationally support the intake camshaft assembly  36  on a second side opposite to the first side corresponding to the first plurality of bearing surfaces  101 . In a non-limiting example, the first portion  100  may be coupled to the second portion  102  by a first plurality of fasteners  105 . Intake camshaft assembly  36  may include a plurality of lobes  136  arranged along its length. 
     Similar to intake camshaft housing assembly  35  described above, the exhaust camshaft housing assembly  37  may include a third portion  110  coupled to a fourth portion  112 . The third portion  110  may provide a third plurality of bearing surfaces  111  on a third side to rotationally support the exhaust camshaft assembly  38 . The fourth portion  112  may provide a fourth plurality of bearing surfaces  113  to rotationally support the exhaust camshaft assembly  38  on a fourth side opposite to the third side corresponding to the third plurality of bearing surfaces  111 . In a non-limiting example, the third portion  110  may be coupled to the fourth portion  112  by a third plurality of fasteners  115 . Exhaust camshaft assembly  38  may include a plurality of lobes  138  arranged along its length. 
     The intake camshaft assembly  36  may be arranged between and rotationally supported by the first and second plurality of bearing surfaces  101 ,  102  of the intake camshaft housing assembly  35  ( FIG. 5 ). The exhaust camshaft assembly  38  may be arranged between and rotationally supported by the third and fourth plurality of bearing surfaces  111 ,  112  of the exhaust camshaft housing assembly  37  ( FIG. 5 ). The intake and exhaust camshaft housing assemblies  35 ,  37 , with intake and exhaust camshaft assemblies  36 ,  38  arranged therein, may be coupled to and supported by the engine structure  30 . 
     In a non-limiting example, the intake and exhaust camshaft housing assemblies  35 ,  37 , with intake and exhaust camshaft assemblies  36 ,  38  arranged therein, may be coupled to and supported by the cylinder head  54 . The intake camshaft housing assembly  35  may be coupled to cylinder head  54  by a second plurality of fasteners  107  that pass through openings  108  in second portion  102  and fasten to cylinder head  54 . Similarly, exhaust camshaft housing assembly  37  may be coupled to cylinder head  54  by a fourth plurality of fasteners  117  that pass through openings  118  in fourth portion  112  and fasten to cylinder head  54 . 
     Oil may be provided to the intake and exhaust camshaft housing assemblies  35 ,  37 , e.g., in order to lubricate the intake and exhaust camshaft assemblies  36 ,  38 . In a non-limiting example, intake camshaft housing assembly  35  may include one or more lubrication structures  109  to provide routing from an oil supply (not shown) to the intake camshaft housing assembly  35  and intake camshaft assembly  36 . A first port  109 A may be defined in lubrication structure  109  to couple to the oil supply. Similarly, exhaust camshaft housing assembly  37  may include one or more lubrication structures  119  to provide routing from an oil supply (not shown) to the exhaust camshaft housing assembly  37  and exhaust camshaft assembly  38 . A second port  119 A may be defined in lubrication structure  119  to couple to the oil supply. 
     In a non-limiting example, one or both of the intake and exhaust camshaft assemblies  36 ,  38  may include cam phasers for providing variable valve timing. Intake and exhaust camshaft housing assemblies  35 ,  37  may include phaser lubrication structures  120 ,  130 , respectively, to provide oil to the cam phasers. Phaser lubrication structure  120  may include a plurality of oil ports  122  for receiving pressurized oil to operate the cam phaser of the intake camshaft assembly  36 . Oil ports  122  may include an advance port for advancing the cam phaser and a retard port for retarding the cam phaser. Similarly, phaser lubrication structure  130  may include a plurality of oil ports  132  for receiving pressurized oil to operate the cam phaser of the exhaust camshaft assembly  38 . Oil ports  132  may include an advance port for advancing the cam phaser and a retard port for retarding the cam phaser. 
     For example only, the engine assembly may be a central direct injection engine. In this type of engine, the intake and exhaust camshaft housing assemblies  35 ,  37  and camshaft assemblies  36 ,  38 , when coupled to the cylinder head  54 , may be separated by an aperture  150  formed in the cylinder head  54 . The spark plugs and fuel injectors to be utilized with the engine assembly  20  may be arranged within the aperture  150 . Oil that lubricates the intake and exhaust camshaft assemblies  36 ,  38  may be prevented from entering the aperture  150 , for example by covering the intake and exhaust camshaft housing assemblies  35 ,  37  with a cam cover (not shown). 
     Engine assembly  20  may be assembled as follows. For example only, intake camshaft assembly  36  may be arranged in the second portion  102  of the intake camshaft housing assembly  35 . Bearing surfaces on intake camshaft assembly  36  may be brought into contact with the second plurality of bearing surfaces  103  of the second portion  102 . The first portion  100  may be coupled with the second portion  102  such that the intake camshaft assembly  36  is arranged between the first and second portions  100 ,  102  and the bearing surfaces on intake camshaft assembly  36  are brought into contact with the first plurality of bearing surfaces  101  of the first portion  100 . The first and second portions  100 ,  102  may be coupled together with a plurality of fasteners  105 . 
     Similarly, exhaust camshaft assembly  38  may be arranged in the fourth portion  112  of the exhaust camshaft housing assembly  37 . Bearing surfaces on exhaust camshaft assembly  38  may be brought into contact with the fourth plurality of bearing surfaces  113  of the fourth portion  112 . The third portion  110  may be coupled with the fourth portion  112  such that the exhaust camshaft assembly  38  is arranged between the third and fourth portions  110 ,  112  and the bearing surfaces on exhaust camshaft assembly  38  are brought into contact with the third plurality of bearing surfaces  111  of the third portion  110 . The third and fourth portions  110 ,  112  may be coupled together with a plurality of fasteners  115 . 
     The intake and exhaust camshaft housing assemblies  35 ,  37  (with their associated intake and exhaust camshaft assemblies  36 ,  38 ) may then be coupled to the engine structure  30 , for example, cylinder head  54 . In a non-limiting example, cylinder head  54  is coupled with engine block  56  before the intake and exhaust camshaft housing assemblies  35 ,  37  (and associated camshaft assemblies  36 ,  38 ) are coupled to the cylinder head  54 . In this manner, the intake and exhaust camshaft housing assemblies  35 ,  37  may be located in a position that restricts access to the fasteners (for example, head bolts) utilized to couple the cylinder head  54  with the engine block  56 , thus reducing the overall size of the engine assembly  20 .