Patent Publication Number: US-10330042-B2

Title: Water jacket for cylinder head

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of priority to Korean Patent Application No. 10-2017-0066143 filed in the Korean Intellectual Property Office on May 29, 2017, the entire content of which is incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to a water jacket for a cylinder head. More particularly, the present disclosure relates to a water jacket for a cylinder head that may improve overall cooling efficiency by controlling coolant flow. 
     BACKGROUND 
     Generally, some of heat generated at a combustion chamber of an engine is absorbed by a cylinder head, a cylinder block, intake and exhaust valves, a piston, etc. 
     When temperatures of the constituent components of the engine excessively increase, the constituent components may be thermally deformed, or an oil film of an inner wall of a cylinder may be degraded such that lubrication performance deteriorates, resulting in thermal problems of the engine. 
     Due to the thermal problems of the engine, abnormal combustion such as combustion failure, knocking, etc. occur, thus a piston may be melted, which may result in serious damage to the engine. Further, thermal efficiency and power of the engine may deteriorate. In contrast, excessive cooling of the engine may cause the power and fuel consumption to deteriorate, and may cause low temperature abrasion of the cylinder, thus it is necessary to appropriately control temperature of the coolant. 
     In this respect, in a typical engine, a water jacket is provided inside a cylinder block and a cylinder head, and a coolant circulating in the water jacket cools a periphery of a spark plug corresponding to a combustion chamber and metal surfaces such as peripheries of an exhaust port, a valve seat, etc. 
     However, in the typical engine, since the coolant flowing in according with the order of cylinders is sequentially circulated in the water jacket provided in the cylinder block, portions of the cylinder block corresponding to upper and lower portions of the combustion chamber at which a relative temperature difference is generated are not effectively cooled, such that the cooling of the engine is not entirely sufficient. 
     In addition, durability of the engine deteriorates due to poor cooling efficiency of the engine, and if a separate cooling jet is provided and a high performance water pump is used in order to prevent the deterioration of the durability of the engine, costs thereof may increase. 
     Further, when the temperature of the coolant is low, viscosity of engine oil is high, thus as frictional force increases, fuel consumption increases, that is, fuel efficiency deteriorates, while when the coolant temperature is excessively high, since knocking occurs, performance of the engine may deteriorate by adjusting ignition timing in order to suppress the knocking. 
     The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art. 
     SUMMARY 
     The present disclosure relates to a water jacket for a cylinder head maximizing a cooling effect by cooling a coolant flowing from a cylinder block into a cylinder head as a cross-flow type to flow from an exhaust valve side to an intake valve side. 
     A water jacket for a cylinder head according to an exemplary embodiment of the present disclosure includes: an upper body disposed at an upper part of the cylinder head inside the cylinder head and through which a coolant flows; a lower body disposed under the upper body inside the cylinder head and through which the coolant flows; and a connector disposed corresponding to a position of an exhaust valve between the upper body and the lower body and integrally connected to the upper body and the lower body, wherein at least one penetration hole is formed in the connector along a length direction. 
     The penetration hole may be respectively formed between each combustion chamber of an engine and at both ends in the length direction of the connector to prevent the coolant inflowing from the lower body from directly inflowing to the upper body. 
     When the coolant inflows from the lower body to the upper body, a flow speed may increase through the connector partition by the penetration hole. 
     The lower body may include: a plurality of inflow protrusions formed for each combustion chamber along the length direction at a lower surface corresponding to the position of the connector; and a plurality of exhaust protrusions formed for each combustion chamber along the length direction at the position facing the inflow protrusion by corresponding to the position of the intake valve. 
     The connector may inflow the part of the coolant inflowing through each inflow protrusion inside the cylinder block to the upper body. 
     Each exhaust protrusion may exhaust the coolant passing through the lower body to the cylinder block except for the coolant inflowing to the upper body through the connector. 
     The coolant inflowing to each inflow protrusion may flow as a cross-flow type so as to pass through an intake valve side from an exhaust valve side of the cylinder head while moving along the length direction of the cylinder head and being exhausted to each exhaust protrusion. 
     The coolant inflowing to the cylinder block through each exhaust protrusion may be exhausted outside from the cylinder block through a separate exhaust core disposed at one side separated from the lower body. 
     A coolant exhaust port may be formed in the upper body. 
     As above-described, according to the water jacket for the cylinder head according to an exemplary embodiment of the present disclosure, as the coolant inflowing from the cylinder block to the cylinder head cools the engine as the cross-flow type so as to flow from the exhaust valve side to the intake valve side, the cooling effect of the engine may be maximized. 
     Also, by forming the penetration hole so as to position the partition dividing the water jacket for the cylinder head into the upper and lower body and preventing the flow of the coolant between each combustion chamber, as the flow speed of the coolant inflowed from the lower body to the upper body increases, the cooling efficiency may be improved through overheating prevention of the exhaust valve side having a relatively high temperature in the cylinder head. 
     Also, a crack of and damage to the cylinder head may be prevented, and durability of the cylinder head may be improved. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a water jacket for a cylinder head according to an exemplary embodiment of the present disclosure. 
         FIG. 2  is a front view of a water jacket for a cylinder head according to an exemplary embodiment of the present disclosure. 
         FIG. 3  is a rear view of a water jacket for a cylinder head according to an exemplary embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     An exemplary embodiment of the present disclosure will hereinafter be described in detail with reference to the accompanying drawings. 
     The embodiment described in the present specification and the configuration shown in the drawings are merely an exemplary embodiment of the present disclosure and do not represent all of the technical spirit of the present disclosure. Thus, it should be understood that there may be various equivalents and modified examples that can replace the embodiments described in the present specification and the configuration shown in the drawings at the time of filing the present application. 
     In order to clearly describe the present disclosure, parts that are irrelevant to the description are omitted, and identical or similar constituent elements throughout the specification are denoted by the same reference numerals. 
     Since the size and thickness of each configuration shown in the drawings are arbitrarily shown for convenience of description, the present disclosure is not necessarily limited to configurations illustrated in the drawings, and in order to clearly illustrate several parts and areas, enlarged thicknesses are shown. 
     Moreover, throughout the specification, unless explicitly described to the contrary, the word “comprise” and variations such as “comprises” or “comprising” will be understood to imply the inclusion of stated elements but not the exclusion of any other elements. 
     Furthermore, terms such as “ . . . unit”, “ . . . means”, “ . . . part”, and “ . . . member” described in the specification mean a unit of a comprehensive configuration having at least one function or operation. 
       FIG. 1  is a perspective view of a water jacket for a cylinder head according to an exemplary embodiment of the present disclosure,  FIG. 2  is a front view of a water jacket for a cylinder head according to an exemplary embodiment of the present disclosure, and  FIG. 3  is a rear view of a water jacket for a cylinder head according to an exemplary embodiment of the present disclosure. 
     Referring to  FIG. 1 , a water jacket  100  for a cylinder head according to an exemplary embodiment of the present disclosure is configured inside a cylinder head  10  in an engine configured of the cylinder head  10  and a cylinder block  20 . 
     The water jacket  100  for the cylinder head, as shown in  FIG. 1  and  FIG. 2 , includes an upper body  110 , a lower body  120 , and a connector  130 . 
     Firstly, the upper body  110  is provided at an upper inside of the cylinder head  10 , and a coolant flows therein. 
     The upper body  110  is provided with eight exhaust valve holes  112  and eight intake valve holes  114  that are formed along a length direction, respectively, and the exhaust valve holes  112  and the intake valve holes  114  are formed at positions corresponding to each combustion chamber. 
     In the present exemplary embodiment, eight exhaust and intake valves hole  112  and  114  are formed at the positions corresponding to each combustion chamber in a four-cylinder engine having four combustion chambers, however it is not limited thereto, and the positions and the number of exhaust and intake valve holes  112  and  114  may be changed and applied depending on the number and positions of the combustion chambers. 
     Here, the upper body  110  may be provided with a protrusion unit  116  protruded outward from the exhaust valve hole  112  so as to increase a flow rate of a coolant into the exhaust valve hole  112  side in which an exhaust gas of a high temperature is exhausted from the cylinder head  10 . 
     Accordingly, the upper body  110  increases the flow rate of the coolant into the exhaust side of the cylinder head  10  through the protrusion unit  116 , thereby efficiently cooling the cylinder head  10 . 
     On the other hand, a coolant exhaust port  118  is formed on the upper body  110 . 
     The coolant exhaust port  118  may exhaust the coolant cooling the upper part of the cylinder head  10  while passing through the upper body  110  outside the cylinder head  10 . 
     In the present exemplary embodiment, the lower body  120  is disposed under the upper body  110  inside the cylinder head  10 . The coolant inflowed from the cylinder block  20  flows in the lower body  120 . 
     The connector  130  is disposed corresponding to the position of the exhaust valve between the upper body  110  and the lower body  120 . The connector  130  integrally connects the upper body  110  and the lower body  120 . 
     Here, at least one penetration hole  132  may be formed along the length direction in the connector  130 . 
     As shown in  FIG. 2 , the penetration hole  132  may be respectively formed between the combustion chambers of the engine and both ends of the connector  130  in the length direction to prevent the coolant inflowing from the lower body  120  from directly inflowing into the upper body  120 . 
     Accordingly, when the coolant inflows from the lower body  120  to the upper body  110 , a flow speed may increase through the connector  130  partitioned by the penetration holes  132 . 
     That is, as the penetration holes  132  prevent the flow of the coolant from flowing into unnecessary parts and simultaneously increases the flow speed of the coolant inflowing to the upper body  120  from the lower body  110 , the coolant may quickly inflow into the upper body. 
     Accordingly, the coolant may quickly inflow into the exhaust valve side having a relatively high temperature on the cylinder head  10  and may efficiently cool the exhaust valve side of the cylinder head  10 . 
     Meanwhile, in the present exemplary embodiment, the lower body  120 , as shown in  FIG. 3 , further includes a plurality of inflow protrusions  122  and a plurality of exhaust protrusions  124 . 
     First, the inflow protrusions  122  are formed for each combustion chamber at the lower surface corresponding to the position of the connector  130  along the length direction. 
     The exhaust protrusions  124  are formed for each combustion chamber along the length direction at the position facing the inflow protrusion  122  by corresponding to the position of the intake valve. 
     Therefore, the coolant inflowing to each inflow protrusion  122  and moving along the length direction of the cylinder head  10  may flow as the cross-flow type to pass through the intake valve side from the exhaust valve side of the cylinder head  10  while being exhausted to each exhaust protrusion  124 . 
     The coolant flow of the cross-flow type may efficiently cool the cylinder head  20  having a relatively higher temperature than the cylinder block  20  because of the exhaust of the exhaust gas. 
     Here, the connector  130  may flow part of the coolant inflowing through each inflow protrusion  122  inside the cylinder block  20  to the upper body  110 . 
     Accordingly, each exhaust protrusion  124  exhausts the coolant passing through the lower body  120  into the cylinder block  20  except for the coolant inflowed to the upper body  110  through the connector  130 . 
     The coolant inflowed to the cylinder block through each exhaust protrusion  124  may be exhausted outside from the cylinder block  20  through a separate exhaust core  140  disposed at one side separated from the lower body  120 . 
     That is, the water jacket  100  for the cylinder head according to an exemplary embodiment of the present disclosure cools the exhaust valve side having the relatively high temperature on the cylinder head  10  by using the coolant quickly inflowed to the upper body  110  from the lower body  120  through the connector  130 . 
     In this case, the protrusion units  116  of the upper body  110  increases the flow rate of the coolant in the exhaust valve side of the cylinder head  10 , thereby efficiently cooling the cylinder head  10 . 
     Further, the lower body  120  inflows the coolant from the cylinder block  20  to the exhaust valve side through the inflow protrusions  122  and cools the cylinder head  20  by using the coolant flowing as the cross-flow type while being flowed in the length direction of the lower body  120  and being again exhausted to the cylinder block  20  through the exhaust protrusions  124  formed at the intake valve side. 
     Accordingly, the lower body  120  cools the lower part of the cylinder head  20  as the cross-flow type, thereby more efficiently cooling the engine. 
     Thus, when applying the above-configured water jacket  100  for the cylinder head  20  according to the exemplary embodiment of the present disclosure, as the coolant inflowed from the cylinder block  20  to the cylinder head  10  cools the engine as the cross-flow type to flow the coolant from the exhaust valve side to the intake valve side, the cooling effect of the engine is maximized. 
     Further, by forming the penetration hole  132  in the connector  130  connecting the upper and lower bodies  110  and  120  so as to position the partition dividing the water jacket for the cylinder head  100  into the upper and lower bodies  110  and  120  and preventing the flow of the coolant between each combustion chamber, as the flow speed of the coolant inflowed from the lower body  120  to the upper body  110  increases, the cooling efficiency may be improved through overheating prevention of the exhaust valve side having the relatively high temperature in the cylinder head  10 . 
     A crack of and damage to the cylinder head  10  may be prevented through the efficient cooling, so the durability of the cylinder head  10  and the engine may be improved. 
     While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.