Patent Publication Number: US-11655776-B1

Title: Cylinder block casting slab core cast geometry for sawcut entrance enhancement

Description:
GOVERNMENT LICENSE RIGHTS 
     This invention was made with government support under United States Department of Energy (USDOE) contract: DE-EE0008877 awarded by the United States Department of Energy. The government has certain rights to the invention. 
    
    
     INTRODUCTION 
     The present disclosure relates to automobile vehicle engine cylinder blocks having water-jacket cooling channels. 
     In automobile vehicle engine blocks a sawcut is machined into a cylinder head area proximate to coolant entry ramps to enhance coolant flow to cylinder walls. The current process for the sawcut geometry requires the sawcut and ramps between the sawcut and the coolant entry ports to be machined in individual bore bridges. The production block will then contain sharp corners between the water-jacket casting surfaces and the sawcuts which generate high stress concentrations and lowers safety factors. In addition to difficulties in machining the sawcuts, the existing entrance ramp shapes are difficult to measure and a positional tolerance of the entrance ramps is difficult to control. 
     Thus, while current engine coolant sawcut designs used in automobile vehicle engine blocks achieve their intended purpose, there is a need for a new and improved engine block design having improved coolant flow designs. 
     SUMMARY 
     According to several aspects, an automobile vehicle engine includes multiple water jackets individually formed in a cast engine block proximate to successive ones of multiple cylinder bores. Multiple cast-in place transition regions are individually formed during a casting operation of the cast engine block at entrances to individual ones of the multiple water jackets. Individual ones of multiple sawcuts open into individual ones of the multiple cast-in place transition regions. 
     In another aspect of the present disclosure, a curved region of the cast-in place transition regions opens into one of the multiple water jackets, the curved region formed during casting at a junction of individual ones of the multiple water jackets and individual ones of the cast-in place transition regions. 
     In another aspect of the present disclosure, individual ones of multiple sawcuts extend into the curved region. 
     In another aspect of the present disclosure, the multiple cast-in place transition regions define a semi-circular shaped slot extending through the curved region. 
     In another aspect of the present disclosure, the multiple cast-in place transition regions include: a first downwardly tapering slot which transitions at a first interface into a second downwardly tapering slot; a surface slot interface between an open end of one of the multiple sawcuts and the second downwardly tapering slot; and the second downwardly tapering slot transitions via a second interface into a curved region which opens into the water jacket. 
     In another aspect of the present disclosure, the multiple cast-in place transition regions individually include a tapering portion which opens into a continuous width portion. 
     In another aspect of the present disclosure, the multiple sawcuts have a first continuous width for a length of the multiple sawcuts. 
     In another aspect of the present disclosure, the continuous width portion defines a semi-circular or a concave shape throughout a length of the continuous width portion and has a second continuous width which is greater than the first continuous width. 
     In another aspect of the present disclosure, the cast-in place transition regions and the corner radius are collectively formed by a sand slab core during casting. 
     In another aspect of the present disclosure, the cast-in place transition regions, the corner radius and the semi-circular shaped slot are collectively shaped by a sand slab core during casting. 
     According to several aspects, an automobile vehicle engine block includes multiple water jackets individually formed in a cast engine block proximate to individual cylinder bores. Multiple cast-in-place transition regions are individually formed during a casting operation forming the cast engine block located proximate to individual ones of the multiple water jackets. A curved region of individual ones of the cast-in-place transition regions opens into one of the multiple water jackets. The cast-in-place transition regions including the curved region are collectively formed as a sand slab core during casting. 
     In another aspect of the present disclosure, multiple sawcuts are created in individual bore bridges positioned between successive ones of the cylinder bores. 
     In another aspect of the present disclosure, individual ones of the multiple sawcuts open into individual ones of the multiple cast-in-place transition regions. 
     In another aspect of the present disclosure, the multiple cast-in-place transition regions have a first end proximate to the curved region and a second end opening into one of the multiple sawcuts, the second end narrower than the first end. 
     In another aspect of the present disclosure, individual ones of the multiple cast-in-place transition regions include: a first semi-circular portion having a first transition zone changing into a second semi-circular portion; and a surface slot interface positioned between an open end of individual ones of the multiple sawcuts and the second semi-circular portion. 
     In another aspect of the present disclosure, the curved region has a concave shape. 
     In another aspect of the present disclosure, a second transition zone transitions from the second semi-circular portion into a downwardly sloping third semi-circular portion which opens into the water jacket. 
     According to several aspects, a method for preparing an automobile vehicle engine block comprises: forming multiple water jackets proximate to individual cylinder bores; individually positioning multiple cast-in place transition regions at entrances to individual ones of the multiple water jackets; and creating a curved region of individual ones of the cast-in-place transition regions which opens into one of the multiple water jackets. 
     In another aspect of the present disclosure, the method further includes: collectively forming the cast-in-place transition regions including the curved region as a sand slab core during casting; and forming a core insert for insertion into the slab sand core. 
     In another aspect of the present disclosure, the method further includes forming the core insert having an inorganic sand core insert. 
     Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples 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 illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
         FIG.  1    is a top plan view of a cylinder block casting slab core cast geometry with surface slot entrance according to an exemplary aspect; 
         FIG.  2    is a top perspective view modified from  FIG.  1   ; 
         FIG.  3    is a top perspective view modified from  FIG.  1   ; 
         FIG.  4    is a top perspective view of area  4  of  FIG.  1   ; 
         FIG.  5    is a top perspective view of area  5  of  FIG.  1   ; 
         FIG.  6    is a top perspective view of area  6  of  FIG.  1   ; 
         FIG.  7    is a cross sectional side elevational view of a slab core for casting the engine block of  FIG.  1   ; and 
         FIG.  8    is a cross sectional side elevational view of a water jacket formed at an interface with a machined deck face and a slab core as-cast for the exemplary aspect of  FIG.  1   . 
     
    
    
     DETAILED DESCRIPTION 
     The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. 
     Referring to  FIG.  1   , a cylinder block casting slab core cast geometry with surface slot entrance  10  includes an engine cylinder block casting  12  for an engine of an automobile vehicle having exemplary multiple cylinder bores including an first cylinder bore  14 , a second cylinder bore  15 , a third cylinder bore  16  and a fourth cylinder bore  18 . Successive pairs of the cylinder bores are separated by a bore bridge such as an exemplary first bore bridge  19 . A quantity of the cylinder bores is not determinative and can vary from two up to twelve cylinder bores within the scope of the present disclosure. A coolant is supplied between successive ones of the cylinder bores into individual ones of multiple water jackets formed during casting in the bore bridges, including: a first water jacket  20  created between the first cylinder bore  14  and the second cylinder bore  15 ; a second water jacket  22  created between the second cylinder bore  15  and the third cylinder bore  16 ; and a third water jacket  24  created between the third cylinder bore  16  and the fourth cylinder bore  18 . 
     To promote effective cooling flow from the water jackets, a sawcut is machined into individual ones of the bore bridges after the casting operation is completed such as for example a first sawcut  26  machined into the first bore bridge  19 . Known sawcuts create coolant passages which include sharp corners and edges at entrance ramps between the sawcut and the water jacket. Known sawcut geometry inhibits coolant flow, therefore according to several aspects transition regions are formed during the casting operation between the location where sawcuts will be machined into bore bridges and individual ones of the water jackets. The transition regions provide a streamlined flow path where individual ones of the sawcuts open into individual ones of the water jackets. According to several aspects, the transition regions may vary in geometry thereby providing multiple optional transition region designs to enhance coolant flow. 
     According to several aspects, a first transition region  28  is created during casting at the first water jacket  20  and an entrance location of the first sawcut  26  when the first sawcut  26  is subsequently machined. The first transition region  28  is shown and described in greater detail in reference to  FIG.  4   . A second sawcut  30  is machined after casting in a second bore bridge  31  separating the second cylinder bore  15  and the third cylinder bore  16 . A second transition region  32  is created during casting at the second water jacket  22  and an entrance location of the second sawcut  30  when the second sawcut  30  is subsequently machined. The second transition region  32  is shown and described in greater detail in reference to  FIG.  5   . Similarly, a third sawcut  34  is machined after casting in a third bore bridge  35  separating the third cylinder bore  16  and the fourth cylinder bore  18 . A third sawcut  34  is machined after casting in a bore bridge separating the third cylinder bore  16  and the fourth cylinder bore  18 . A third transition region  36  is created during casting at the third water jacket  24  and an entrance location of the third sawcut  34  when the third sawcut  34  is subsequently machined. The third transition region  36  is shown and described in greater detail in reference to  FIG.  6   . 
     According to several aspects, a minimum clearance  38  of 4.5 mm is maintained between a cylinder bore wall  40  of any of the cylinder bores and a closest point-of-approach of the cylinder bore wall  40  to a transition region wall  42  of any of the transition regions. The minimum clearance  38  is maintained to retain an operational strength and rigidity of the engine cylinder block casting  12  where cast material is omitted to create the transition regions. 
     Referring to  FIG.  2    and again to  FIG.  1   , according to several aspects, a cylinder block casting slab core cast geometry with surface slot entrance  44  differs from the cylinder block casting slab core cast geometry with surface slot entrance  10  as follows. A sawcut  46  having a first continuous width  47  over its length is machined into a machined deck face  48  of a fourth bore bridge  50  which separates an exemplary cylinder bore  52  and a next successive cylinder bore  54 . The sawcut  46  at an interface  56  opens into a transition region  58  having a tapering portion  60  which opens into a continuous width portion  62 . The continuous width portion  62  defines a semi-circular or a concave shape throughout its length and has a second continuous width  64  which is greater than the first continuous width  47  of the sawcut  46 . The sawcut  46  transitions from the continuous width portion  62  via a curved transition region  66  into a curving portion  68  to open into a water jacket  70 . An interface junction  72  between the continuous width portion  62  and the curving portion  68  is rounded to further reduce coolant flow drag and flow resistance. 
     Referring to  FIG.  3    and again to  FIGS.  1  and  2   , according to several aspects, a cylinder block casting slab core cast geometry with surface slot entrance  74  differs from the cylinder block casting slab core cast geometry with surface slot entrance  10  and the cylinder block casting slab core cast geometry with surface slot entrance  44  as follows. A sawcut  76  having a first continuous width  77  over its length is machined into a machined deck face  78  of a fifth bore bridge  79  which separates successive cylinder bores. The sawcut  76  at a rounded interface  80  opens into a transition region  82  defining a continuously tapering portion  84  which continuously increases in width between the rounded interface  80  and a curved transition region  86 . The curved transition region  86  transitions into a curving portion  88  which opens into a water jacket  90 . The continuously tapering portion  84  defines a semi-circular or a concave shape throughout its length. An interface junction  92  between the transition region  82  and the curved transition region  86  is rounded to further reduce coolant flow drag and flow resistance. 
     Referring to  FIG.  4    and again to  FIG.  1   , the first transition region  28  may include a downwardly sloping portion  94  which transitions into a curved region  96  which opens into the first water jacket  20 . A surface slot interface  98  between an open end of the first sawcut  26  and the curved region  96  reduces turbulence for coolant flowing into the first sawcut  26 . 
     Referring to  FIG.  5    and again to  FIG.  1   , the second transition region  32  may include a first downwardly tapering slot  100  which transitions at a first interface  102  into a second downwardly tapering slot  104 . A surface slot interface  106  between an open end of the second sawcut  30  and the second downwardly tapering slot  104  reduces turbulence for coolant flowing into the second sawcut  30 . The second downwardly tapering slot  104  transitions via a second interface  108  into a curved region  110  which opens into the second water jacket  22 . 
     Referring to  FIG.  6    and again to  FIG.  1   , the third transition region  36  differs from the first transition region  28  by the use of semi-circular flow passages. The third transition region  36  may include a first semi-circular portion  112  which at a first transition zone  114  changes into a second semi-circular portion  116 . A surface slot interface  118  between an open end of the third sawcut  34  and the second semi-circular portion  116  reduces turbulence for coolant flowing into the third sawcut  34 . From the second semi-circular portion  116  a second transition zone  120  transitions into a downwardly sloping third semi-circular portion  122  which opens into the third water jacket  24 . 
     Referring to  FIG.  7    and again to  FIG.  1   , a slab core  124  as-cast geometry provides an approximately 10 mm depth of a water jacket  126 . An approximate 4.75 mm split line  128  below a machined deck face  130  eliminates a need to machine a V-shaped sawcut. 
     Referring to  FIG.  8    and again to  FIG.  7   , a water jacket  132  formed at an interface with the machined deck face  130  and a slab core  134  provides approximately 10 mm of the water jacket geometry  136  within the slab core  134  at multiple locations. A split line at approximately 4.75 mm below the machined deck face  130  is provided only at the locations of the water jacket geometry  136  to provide for the formation of transition regions  138  which may be formed as any of the transition regions discussed herein. 
     A cylinder block casting slab core cast geometry with surface slot entrance of the present disclosure offers several advantages. These include elimination of sharp corners between a cast water jacket and a known sawcut to create a more streamlined shape to be cast into the cylinder block. This geometry provides transition regions which eliminate machined entrance ramps for the machined sawcuts. The slot sand core may be formed using an in-organic sand core insert which is molded together with a slab sand core. 
     The description of the present disclosure is merely exemplary in nature and variations that do not depart from the gist of the present disclosure are intended to be within the scope of the present disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the present disclosure.