Patent Publication Number: US-9410472-B2

Title: Internal combustion engine with cartridge style water pump assembly

Description:
BACKGROUND 
     A known water pump for an internal combustion engine includes a pump housing secured to a front end of a cylinder block and an impeller rotatably supported on the pump housing. The water pump typically requires disassembly of certain engine components to which the water pump is attached in order to gain access to pump bearings, seals, impellers, etc., as for replacements. For example, it is known to position a water pump behind a timing chain with an impeller of the water pump being driven by the timing chain. The pump housing of the water pump for housing the impeller is located on the same component that supports a pump bearing and shaft. However, with this known arrangement, servicing and/or replacement of the water pump requires disassembly of the timing chain system and can be difficult and expensive. 
     BRIEF DESCRIPTION 
     In accordance with one aspect, an internal combustion engine for a vehicle comprises a cylinder block having a cylinder head connected to an upper end of the cylinder block. A front end of the cylinder block has a coolant introduction passage. A timing chain provided at the front end of the cylinder block is engaged to a camshaft sprocket operably associated with the cylinder head. A timing chain cover is mounted to the cylinder block and spaced forward of the front end of the cylinder block. A water pump assembly includes a pump housing and an impeller assembly. The pump housing is directly secured to the cylinder block and interposed between the timing chain cover and the front end of the cylinder block. The pump housing has a pump chamber in fluid communication with the coolant introduction passage. The impeller assembly is removably mounted in the pump chamber of the pump housing. The impeller assembly includes an impeller having a hub affixed to a drive shaft to be rotated about an axis defined by the drive shaft. An end of the drive shaft extends forward of the timing chain cover. The impeller assembly is adapted to be removed from the pump housing without removal of the timing chain cover. 
     In accordance with another aspect, a V-type internal combustion engine comprises a cylinder block having left and right banks and left and right spaced cylinder heads fixedly connected to respective upper ends of the left and right banks of the cylinder block. A front end of the cylinder block has a coolant introduction passage. At least one timing chain provided at the front end of the cylinder block is engaged to a camshaft sprocket operably associated with one of the left and right cylinder heads. A timing chain cover is mounted to the cylinder block and spaced forward of the front end of the cylinder block. The front end of the cylinder block and the timing chain cover together define a partially enclosed space for housing the at least one timing chain. A water pump assembly includes a pump housing and an impeller assembly. The pump housing is directly secured to both the cylinder block and at least one of the left and right cylinder heads. The pump housing is interposed between the timing chain cover and the front end of the cylinder block. A mounting structure of the pump housing is sealingly engaged to the cylinder block and the one cylinder head and is positioned behind the at least one timing chain. The pump housing has a pump chamber in fluid communication with the coolant introduction passage. The impeller assembly is removably mounted in the pump chamber of the pump housing. The impeller assembly includes an impeller having a hub affixed to a drive shaft to be rotated about an axis defined by the drive shaft. The drive shaft of the impeller assembly is driven by a front end accessory drive belt located forward of the timing chain cover. 
     In accordance with yet another aspect, a method of mounting a water pump assembly to a V-type internal combustion engine is provided. The method comprises positioning a mounting structure of a pump housing of the water pump assembly behind a timing chain located at a front end of a cylinder block of the internal combustion engine; positioning the pump housing on the front end of the cylinder block such that a pump chamber defined by the pump housing is in communication with a coolant introduction passage provided on the front end of the cylinder block; securing the mounting structure of the pump housing directly to both the cylinder block and to left and right cylinder heads of the internal combustion engine; releasably securing an impeller assembly of the water pump assembly in the pump chamber of the pump housing; aligning an opening located on a timing chain cover with the impeller assembly such that a drive shaft of the impeller assembly projects outwardly from the timing chain cover; mounting the timing chain cover to the front end of the cylinder block, the opening being dimensioned to allow the impeller assembly to be removed from the pump housing without removal of the timing chain cover from the cylinder block; and mounting a front end accessory drive belt to the drive shaft of the impeller assembly. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a front schematic view of an internal combustion engine with a cartridge style water pump assembly. 
         FIG. 2  is a front schematic view of  FIG. 1  with a timing chain cover partially broken away to depict a timing chain and the water pump assembly. 
         FIG. 3  is a cross-sectional view taken along line  3 - 3  of  FIG. 1  according to one aspect of the present disclosure. 
         FIG. 4  is an exploded view of  FIG. 3 . 
         FIG. 5  is an exploded perspective view of the water pump assembly of  FIG. 1 . 
         FIG. 6  is a cross-sectional view taken along line  3 - 3  of  FIG. 1  according to another aspect of the present disclosure 
     
    
    
     DETAILED DESCRIPTION 
     It should, of course, be understood that the description and drawings herein are merely illustrative and that various modifications and changes can be made in the structures disclosed without departing from the present disclosure. In general, the figures of the exemplary internal combustion engine with cartridge style water pump assembly are not to scale. It will also be appreciated that the various identified components of the exemplary internal combustion engine with cartridge style water pump assembly disclosed herein are merely terms of art that may vary from one manufacturer to another and should not be deemed to limit the present disclosure. 
     Referring now to the drawings, wherein like numerals refer to like parts throughout the several views,  FIGS. 1 and 2  schematically illustrate an internal combustion engine  100  for a vehicle (not shown). The internal combustion engine  100  includes a cylinder block  102  having a cylinder head  104  connected to an upper end of the cylinder block. In the depicted embodiment, the internal combustion engine  100  is a V-type internal combustion engine and the cylinder block  102  has left and right banks  110 ,  112  and the cylinder head  104  is defined by left and right cylinder heads  114 ,  116  fixedly connected to respective upper ends of the left and right banks  110 ,  112  of the cylinder block. At least one timing chain  120  is provided at a front end  140  of the cylinder block  102  and engaged to at least one camshaft sprocket  122  operably associated with the cylinder head  104 . With the V-type internal combustion engine, the at least one timing chain  120  includes a first timing chain  124  engaged to camshaft sprockets  126  operably associated with the left cylinder head  114  and a second timing chain  128  engaged to camshaft sprockets  130  operably associated with the right cylinder head  116 . As shown in  FIG. 2 , a crankshaft  132  is installed on a lower end of the cylinder block  102 . A crankshaft sprocket  134  is installed on the crankshaft  132  for rotation therewith. The first timing chain  124  is placed around and engaged with the camshaft sprockets  126  and the crankshaft sprocket  134  and the second timing chain  128  is placed around and engaged with the camshaft sprockets  130  and the crankshaft sprocket  134 . 
     A timing chain cover  136  is mounted to the cylinder block  102  so as to cover the cylinder block and a lower part of each of the left and right cylinder heads  114 ,  116 . The timing chain cover  136  can be fixedly attached to the cylinder block by any mechanical means known in the art, such as but not limited to bolts which threadingly engage mounting holes located on the cylinder block  102 . A forward wall or surface  138  of the timing chain cover  136  is spaced forward of the front end  140  of the cylinder block  102 . As best depicted in  FIG. 3 , the front end  140  of the cylinder block  102  and the forward wall  138  of the timing chain cover  136  together define a partially enclosed space or timing chain chamber  142  for housing the first and second timing chains  124 ,  128 . As shown in  FIG. 2 , a pair of timing chain guides  150 ,  152  supported on the front end  140  of the cylinder block  102  provides tension to the first timing chain  124 . Similarly, a pair of timing chain guides  154 ,  156  also supported on the front end  140  of the cylinder block  102  provides tension to the second timing chain  128 . 
     The internal combustion engine  100  further includes an exemplary water pump assembly  160  according to the present disclosure. With reference to  FIGS. 3-5 , the water pump assembly  160  includes a pump housing  162  and an impeller assembly  164 . The pump housing  162 , which can be a one-piece pump housing, is directly secured to the both the cylinder block  102  and at least one of the left and right cylinder heads  114 ,  116 . As depicted, a mounting structure  166  of the pump housing  162  is sealingly engaged to both the cylinder block  102  and each of the left and right cylinder heads  114 ,  116 . The pump housing  162  is further interposed between the timing chain cover  136  and the front end  140  of the cylinder block  102  with the mounting structure  166  of the pump housing positioned behind each of the first and second timing chains  124 ,  128 . The pump housing  162  includes a body  168  defining a pump chamber  170  in fluid communication with a coolant introduction passage  172  located at the front end  140  of the cylinder block  102 . The body  168  extends from the front end  140  of the cylinder block  102  a distance approximately equal to the spacing between the front end  140  and the forward wall  138  of the timing chain cover  136 , with the body  168  at least partially supporting the forward wall  138 . 
     The mounting structure  166  extends from the body  168  and has a first portion  178  secured to the cylinder block  102  and a second portion  180  secured to the left and right cylinder heads  114 ,  116 . In the depicted embodiment, the first portion  178  of the mounting structure  166  extends radially from and at least partially circumscribes the body  168 . A plurality of spaced mounting openings  182  is provided on the first portion  178 , and according to one aspect, the mounting openings  182  are located on spaced tabs  184  projecting from the first portion. The mounting openings  182  are sized to receive fasteners, such as bolts, which extend through the openings and threadingly engage corresponding mounting holes (not shown) on the front end  140  of the cylinder block  102 . The second portion  180  of the mounting structure  166  extends perpendicularly from the body  168  and is sized to interconnect the left and right cylinder heads  114 ,  116 . Similar to the first portion  178 , a plurality of spaced mounting openings  188  is provided on the second portion  180 , and the mounting openings  188  can be located on spaced tabs  190  projecting from the second portion. The mounting openings  188  are sized to receive fasteners, such as bolts, which extend through the openings and threadingly engage corresponding mounting holes (not shown) on the left and right cylinder heads  114 ,  116 . With this configuration of the mounting structure  166 , the pump housing  162  is supported on both the cylinder block  102  and the cylinder heads  114 ,  116 . 
     Further, as shown in  FIG. 5 , at least one strengthening rib  194  extends from the body  168  and onto the second portion  180  of the mounting structure  166 . In the depicted embodiment, the pump housing  162  is provided with three spaced strengthening ribs  194 ,  196 ,  198 . With reference back to  FIG. 2 , an end portion  200  of the timing chain guide  156  is connected to the strengthening rib  194 . To this end, the strengthening rib  194  can be provided with a cutout  202  dimensioned to receive the end portion  200  and the end portion  200  can include a recess (not shown) for engaging the strengthening rib  194 . Therefore, the exemplary pump housing  162  can be used to support components of the timing chain system. 
     With reference again to  FIGS. 3-5 , the impeller assembly  164  is removably mounted in the pump chamber  170  of the pump housing  162 . In the depicted embodiment, the impeller assembly  164  includes an impeller  210  having a hub  212  affixed to a first end portion  214  of a drive shaft  216  to be rotated about an axis defined by the drive shaft. The drive shaft  216  is housed in an impeller housing  220  dimensioned to be received in the pump chamber  170 . In the illustrated embodiment, an inner surface  222  of the body  168  that defines the pump chamber  170  is cylindrical shaped with an axis coincident with the drive shaft axis, and the impeller housing  220  is similarly shaped. The impeller assembly  164  also may include a single bearing or a pair of bearings  224 ,  226  positioned between a periphery of the drive shaft  216  and an inner surface  228  of the impeller housing  220  which defines a bore  230 . The bearings  224 ,  226  mount the drive shaft  216  in the bore  230  of the impeller housing  220  for rotation. As shown, bearing  224  is located between an end wall  232  of the impeller housing  220  and an enlarged section  234  of the drive shaft  216 . A retaining ring  236  can be positioned on a second end portion  238  of the drive shaft  216  to retain the bearing  226  against the enlarged section  234  in the impeller housing  220 . In addition, to prevent intrusion of coolant into the bearings  224 ,  226 , an annular seal  240  is provided about a section of the first end portion  214  of the drive shaft  216  that extends through the end wall  232 , between the impeller  210  and bearing  224 . Additional seals  242 ,  244  are located between an outer surface  246  of the impeller housing  220  and the inner surface  222  of the body  168 . The seals  242 ,  244  are provided in respective annular grooves  250 ,  252  in the outer surface  246 . A weep hole (not shown) provided in the impeller housing  220  extends to a clearance at the annular seal  240  to drain leakage to the exterior of the pump housing  162 . 
     A mounting flange  260  having spaced mounting openings  262  is formed with the impeller housing  220  opposite the end wall  232 . The mounting flange  260  has a shape corresponding to a forward annular mounting flange  266  provided on the body  168  of the pump housing  162 . A mounting face  268  of the flange  266  includes spaced threaded apertures  270 . The mounting flange  260  of the impeller assembly  164  is fastened to the face  268  of the mounting flange  266  of the pump housing  162 , for example, by the depicted bolts  274 . Further, the timing chain cover  136  includes an opening  280  which when the timing chain cover  136  is mounted to the cylinder block  102  is axially aligned with the pump chamber  170 . The opening  280  is dimensioned to receive the mounting flanges  260 ,  266 , and as shown, a surface  282  of the timing chain cover  136  that defines the opening  280  abuts an outer surface  284  of the mounting flange  266 . In the assembled condition shown in  FIG. 3 , the mounting flange  260  is outwardly spaced from the forward wall  138  of the timing chain cover  136 . The second end portion  238  of the drive shaft  216  has a water pump sprocket  290  installed thereon, by, for example, a bolt  292  extending through an opening  294  in the sprocket  290  and threaded in an aperture  296  in the second end portion  238 . The sprocket  290  is driven by a front end accessory drive belt  300  ( FIG. 1 ). The water pump sprocket  290  is located outside and forward of the timing chain cover  136 . The sprocket  290  and belt  300  may be of toothed construction, as is typical in timing belts. Because the impeller assembly  164  includes the moving parts which may need replacement, such replacement is quickly and easily facilitated as by easy separation of the impeller assembly  164  from the pump housing  162 , and the opening  280  allows the impeller assembly  164  to be removed from the pump housing  162  without removal of the timing chain cover  136  from the cylinder block  102 . Ease of disconnection of the impeller assembly  164  from the pump housing  162  is clear from  FIG. 5 . 
     With reference again to  FIGS. 3 and 4 , the pump housing  162  includes a cylindrical shaped flange or conduit  310  extending from the mounting structure  166  opposite the body  168 . The conduit  310  is dimensioned to be received in the coolant introduction passage  172  provided in the front end  140  of the cylinder block  102  and defines a fluid passage  312  in communication with the pump chamber  170 . The pump housing  162  further defines a volute  318  located downstream of the fluid passage  312  of the conduit  310  and upstream of the pump chamber  170 . A discharge port  320  provided on the mounting structure  166  spaced from the conduit  310  is in communication with the volute  318 . In the assembled condition ( FIG. 3 ), the impeller  210  is located in the volute  318 , and coolant received in the pump chamber  170  from the fluid passage  312  flows in an outward direction to the volute  318  as the impeller  210  rotates. The coolant is then directed from the volute  318  to the discharge port  320 . Coolant pressurized by the water pump assembly  160  is forced to flow from the front end  140  of the cylinder block  102  into the water jackets  324  of the cylinder block  102  and the water jackets (not shown) of the left and right cylinder heads  114 ,  116  and then rearward of the internal combustion engine  100 . As is well known, thereafter, coolant is discharged from a coolant outlet at a rear end of the engine  100  and conducted through a coolant passage to a radiator (not shown). From the radiator, coolant is conducted back into the coolant introduction passage  172  and water pump assembly  160 . 
       FIG. 6  depicts a water pump assembly  160 ′ according to another aspect of the present disclosure. Except as indicated herein, the water pump assembly is the same as the water pump assembly  160  of  FIGS. 3-5  and thus like reference numerals are used on like components (similar components are also identified with like reference numerals, but with a primed (′) suffix, and new components are identified with new numerals). As shown in  FIG. 6 , the water pump assembly  160 ′ includes the pump housing  162 ′ and the impeller assembly  164 ′. The pump housing  162 ′ includes the mounting structure  166 ′ sealingly engaged to both the cylinder block  102  and at least one of the left and right cylinder heads  114 ,  116 . The pump housing  162 ′ is further interposed between the timing chain cover  136 ′ and the front end  140  of the cylinder block  102  with the mounting structure  166 ′ of the pump housing  162 ′ positioned behind each of the first and second timing chains  124 ,  128  (only the first timing chain  124  is visible in  FIG. 6 ). 
     The impeller assembly  164 ′ is removably mounted in the pump chamber  170 ′ of the pump housing  162 ′. The impeller assembly  164  includes the impeller  210 ′ affixed to the drive shaft  216 ′ housed in the impeller housing  220 ′. The pair of bearings  224 ′,  226 ′ positioned on the drive shaft  216 ′ mounts the drive shaft in the bore  230 ′ of the impeller housing  220 ′. Again to prevent intrusion of coolant into the bearings  224 ′,  226 ′, the annular seal  240 ′ is provided about the drive shaft  216 ′. A drain passage  330  provided in the impeller housing  220 ′ is in communication with the bore  230 ′ to drain leakage to the exterior of the pump housing  162 ′. The mounting flange  260 ′ of the impeller assembly  164 ′ is fastened to the mounting flange  266 ′ of the pump housing  162 ′, for example, by the depicted bolts  274 . According to the aspect depicted in  FIG. 6 , the timing chain cover  136 ′ includes the opening  280 ′ dimensioned to receive the impeller housing  220 ′. In the assembled condition, a portion  336  of the timing chain cover  136 ′ is sandwiched between mounting flange  260 ′ of the impeller assembly  164 ′ and the mounting flange  266 ′ of the pump housing  162 ′. This arrangement also allows for easy separation of the impeller assembly  164 ′ from the pump housing  162 ′ without removal of the timing chain cover  136 ′ from the cylinder block  102 . 
     As is evident from the foregoing, the present invention provides a method of mounting the water pump assembly  160  to the V-type internal combustion engine  100 . The method comprises positioning the mounting structure  166  of the pump housing  162  behind the timing chain  120  located at the front end  140  of the cylinder block  102  of the internal combustion engine  100 ; positioning the pump housing  162  on the front end  140  such that the pump chamber  170  defined by the pump housing  162  is in communication with the coolant introduction passage  172  provided on the front end  140  of the cylinder block  102 ; securing the mounting structure  166  of the pump housing  162  directly to both the cylinder block  102  and to the left and right cylinder heads  114 ,  116 ; releasably securing the impeller assembly  164  in the pump chamber  170 ; aligning the opening  280  located on the timing chain cover  136  with the impeller assembly  164  such that the drive shaft  216  of the impeller assembly projects outwardly from the timing chain cover  136 ; mounting the timing chain cover  136  to the front end  140  of the cylinder block  102 , the opening allowing the impeller assembly to be removed from the pump housing without removal of the timing chain cover from the cylinder block; and mounting the front end accessory drive belt  300  to the drive shaft  216 . The method further includes sandwiching a portion of the timing chain cover between the pump housing and the impeller assembly. The method further includes supporting the timing chain guide  156  on the front end  140  of the cylinder block for providing tension to the timing chain  120  and connecting the end portion  200  of the timing chain guide  156  directly to the pump housing  162 . 
     The present invention relates to the cartridge style water pump assembly  160  configured to be driven by the drive belt  300  of a front engine accessory drive. The pump housing  162  for housing the impeller assembly  164  is housed in the enclosed space  142  defined by the timing chain cover  136  and the mounting structure  166  is positioned behind the timing chain  120  so that it remains part of the cylinder block  102 . This allows for removal of the impeller assembly  164  from the pump housing  162  for servicing and/or replacement without removal of the timing chain cover  136  and disassembly of the timing chain system. 
     It will be appreciated that various of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Also that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.