Abstract:
A cooling system is provided for an engine utilizing a parallel flow configuration such that coolant flows from the outer regions of the engine block into the engine block&#39;s inner core. Parallel flow is used to maintain equivalent cylinder temperatures.

Description:
FIELD OF THE INVENTION  
         [0001]    The present invention relates generally to an engine cooling system. In particular, the present invention relates to a cross flow engine cooling system wherein coolant moves from the outer regions of the engine block into the engine block&#39;s inner core in a parallel flow configuration.  
         BACKGROUND OF THE INVENTION  
         [0002]    A cooling system for engines is well known in the art. Typical engine cooling systems work by pumping coolant through the engine in an axial flow direction. Specifically, a coolant pump feeds coolant directly into the engine block&#39;s coolant jacket. The coolant flows from the front of the block to the back of the block, with the coolant increasing in temperature as it flows from front to back. Then, the coolant flows up into the back of the cylinder head and through to the front of the cylinder head where it flows to an outlet at the top of the engine. Similarly, the flow of the coolant from the back to the front of the cylinder head results in another coolant temperature increase.  
           [0003]    This cooling system results in the engine&#39;s front cylinders having the coldest bores and hottest combustion chambers, while the rear cylinders have the hottest bores and coldest combustion chambers. This variation in cylinder temperatures can exceed 30 degrees. Further, since each cylinder is cooled differently, piston ring sealing and spark timing is different for each cylinder.  
           [0004]    In order to get around this problem, especially in high performance applications, manufacturers have resorted to running exterior coolant lines from the coolant pump to the sides of the engine block to force more coolant flow around the rear cylinders. Additionally, external lines have been used to enhance coolant flow at selected cylinder head hot spots. Hence, engine packaging is increased which in turn increases system cost and chance of failure.  
           [0005]    Accordingly, a need exists for a cooling system that minimizes temperature variation between the cylinders without increasing the engine package.  
         SUMMARY OF THE INVENTION  
         [0006]    The present provides a cooling system for an engine with multiple cylinders. This system employs at least one inlet manifold with multiple coolant passages which are associated with a respective cylinder coolant jacket. The inlet manifold serves to bring coolant into the engine. The coolant from the inlet manifold flows through the coolant passages into the respective cylinder coolant jacket. The coolant entering each of the respective cylinder coolant jackets is generally of the same temperature, hence this coolant system reduces the temperature of the cylinders with little variation between cylinder temperatures.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:  
         [0008]    [0008]FIG. 1 is a three-dimensional perspective view of an internal combustion engine exhibiting coolant flow according to the principles of the present invention;  
         [0009]    [0009]FIG. 2 of the present invention is a front view of the internal combustion engine shown in FIG. 1;  
         [0010]    [0010]FIG. 3 is a side view of the engine block shown in FIG. 1;  
         [0011]    [0011]FIG. 4 is a top view of the deck of a cylinder section of the block of the internal combustion engine according to the principles of the present invention;  
         [0012]    [0012]FIG. 5 is a side view of the cylinder head of the internal combustion engine of the present invention;  
         [0013]    [0013]FIG. 6 is a top view of the coolant outlet manifold for the internal combustion engine according to the principles of the present invention; and  
         [0014]    [0014]FIG. 7 is a cross sectional view along line  7 - 7  of FIG. 1. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0015]    The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.  
         [0016]    The present invention is generally related to a cooling system for an engine. In this regard, the cooling system will be described in the context of an internal combustion engine with eight cylinders in a ninety degree formation. However, it is to be understood that the principles embodied herein are equally applicable to other types of engines and engines in different formations as well.  
         [0017]    [0017]FIG. 1 is a three-dimensional perspective view of an engine  10  including a coolant entry section  12  in fluid communication with a coolant distribution system  14  which is also in fluid communication with a coolant exit system  16 . The distribution system  14  and coolant exit system  16  will be discussed with reference to only one side of the engine  10 . It is to be understood that the distribution system  14  and exit system  16  are identical on either side of the engine.  
         [0018]    Referring to FIG. 2, the coolant entry section  12  includes an entry port  18  in fluid communication with a pump  20 , as shown in the art. The pump  20  is positioned on the front of the engine  10 . The pump  20  is in fluid communication with two feeder lines,  22  and  24 . Feeder line  22  is located on the right side of the engine  10 , and feeder line  24  is on the left side of the block. Both feeder lines  22  and  24  are in fluid communication with the distribution system  14 .  
         [0019]    The distribution system  14  has an inlet manifold  26  in fluid communication with the entry section  12 . The inlet manifold  26  runs along the side of the engine  10  and defines a manifold chamber  26 A that decreases in area from front to back as best shown in FIG. 3. The inlet manifold  26  in FIG.  3  is encircled with dashed lines and is also detailed in FIG. 7. Now referring to FIG. 4, the distribution system  14  further includes a coolant network  28  and a cylinder head  38 . This coolant network  28  is in fluid communication with the cylinder head  38 .  
         [0020]    The coolant network  28  includes multiple coolant passages  30 , best shown in FIGS. 4 and 7, which are in fluid communication with the inlet manifold  26 . Referring to FIGS. 4 and 7, these coolant passages  30  are also in fluid communication with a respective cylinder coolant jacket  32 . The individual cylinder coolant jackets  32  combine to make up a coolant chamber  34 . This coolant chamber  34  surrounds the cylinders  36 . The cylinders  36  in the engine  10  each share a wall, commonly known as a Siamese configuration, but they could also be in a standard spaced apart pattern, such that the coolant jackets  32  fully encircle the individual cylinders.  
         [0021]    Referring to FIG. 5, a side view of the cylinder head  38  of the distribution system  14  is shown. The cylinder head  38  is in fluid communication with the coolant network  28  and includes bolt holes  40  which receive bolts (not shown) which also engage the bolt holes in the engine  10 . Specifically, multiple coolant passages (not shown) in the cylinder head area  38  are in fluid communication with the coolant chamber  34 . These coolant passages are also in fluid communication with exit ports  42 ,  44  and  46  in the side of the cylinder head  38 . The exit ports  42 ,  44 , and  46  are aligned in parallel, with central exit port  44  sized such that it is approximately twice the size of exit ports  42  and  46 . This ensures uniform coolant flow. The exit ports  42 ,  44  and  46  are in further fluid communication with the coolant exit system  16 .  
         [0022]    With reference to FIG. 6, coolant exit system  16  includes cylinder outlet passages  48  in fluid communication with distribution system  14 . Specifically, the cylinder outlet passages  48  are in fluid communication with exit ports  42 ,  44  and  46 . These cylinder outlet passages are also fluidly coupled to an outlet manifold  50 . The outlet manifold  50  is in fluid communication with an outlet  52 . Outlet  52  is in fluid communication with a radiator (not shown). The manifold  50  includes bolt holes  51  which receive bolts (not shown) which also engage the bolt holes  40  in the cylinder head  38 .  
         [0023]    [0023]FIG. 7 is a cross-section of the engine  10 , taken through the third and fourth cylinders  36 . The cylinders  36  have corresponding cylinder coolant jackets  32 . The coolant passages  30  fluidly connect the cylinder coolant jackets  32  to the inlet manifold  26 . Specifically, the coolant passages  30  fluidly connect the cylinder coolant jackets  32  to the coolant flow area  26 A of the inlet manifold  26 . In this cross section, the inlet manifold coolant flow area  26 A has been slightly reduced to ensure proper flow distribution at the rear of the inlet manifold  26 .  
         [0024]    During operation of the engine  10 , coolant enters the pump  20  through an entry port  18 . The pump then forces the coolant into two feeder lines  22  and  24 . Following feeder line  24  only, with the understanding that the process is identical for both feeder line  22  and  24 , feeder line  24  sends coolant into the inlet manifold  26 . From inlet manifold  26 , coolant is carried by coolant passages  30  into the respective cylinder coolant jackets  32 . The coolant flows from the coolant jackets  32  and around the coolant chamber  34  as illustrated by the arrows A in FIG. 4. The coolant from the coolant chamber  34  is then forced up into the cylinder head  38  through multiple coolant passages. From the cylinder head  38 , coolant flows out exit ports  42 ,  44  and  46  into the respective outlet passages  48 . From the outlet passages  48 , coolant flows into the outlet manifold  50  where it is forced to exit the system through outlet  52  into the radiator.  
         [0025]    The cooling system of the present invention greatly reduces temperature variation between cylinders. Test results have shown variation as low as 12 degrees across the entire engine, hence improving engine performance and durability by reducing the occurrence of hot piston scuffing and detonation as well as improved ring sealing and reduced piston ring tension. In addition, this system allows flow to be precisely targeted to each area of the engine through manipulation of the diameter of the coolant passages. In this embodiment, the inlet manifold  26  is cast in the engine  10 , and thus reduces external packaging.