Patent Publication Number: US-2013228141-A1

Title: Cooling device for engine

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is based on and incorporates herein by reference Japanese Patent Application No. 2012-046689 filed on Mar. 2, 2012. 
     TECHNICAL FIELD 
     The present disclosure relates to a cooling device for an engine, through which a coolant passes to cool the engine. 
     BACKGROUND 
     Conventionally, there is a cooling device that cools an engine by using a coolant and includes a flow control valve to adjust a flow rate of the coolant. Such flow control valve is disclosed in Patent Document 1 (JP 2005-249021 A). A flow control valve in Patent Document 1 includes a housing having a flow passage through which water passes, and a valve body arranged in the housing. By moving the valve body, a cross-sectional area of the flow passage is adjusted. 
     When the water freezes in the flow passage of the housing in the flow control valve of Patent Document 1, the valve body may be fixed not to move, and the flow rate of the water may become unable to be adjusted. In a cooling device for an engine, a coolant may freeze when an outside temperature is low. Thus, even when the coolant freezes, a flow control valve may be required to become operable promptly. 
     SUMMARY 
     It is an objective of the present disclosure to make a valve body of a flow control valve be movable promptly even when a coolant around the valve body freezes in a cooling device for an engine. 
     According to an aspect of the present disclosure, a cooling device for an internal combustion engine includes a jacket and a flow control valve. The jacket is provided in the engine such that a coolant is capable of flowing through the jacket. The flow control valve is connected to at least one of an inlet side of the jacket and an outlet side of the jacket to adjust a flow rate of the coolant. The flow control valve includes a housing, a valve body and a heat transfer member. The housing has a flow passage communicating with the jacket such that the coolant is capable of flowing through the flow passage. The valve body is arranged in the housing to open or close the flow passage. The heat transfer member contacts the engine and a part of the housing accommodating the valve body to transfer a heat from the engine to the housing. 
     Accordingly, a combustion heat of the engine is transferred to the part of the housing accommodating the valve body through the heat transfer member. Therefore, even when the coolant around the valve body freezes, the frozen coolant can be melted by the heat transferred from the engine, and the valve body becomes movable promptly. 
     The housing may be connected to the engine such that the flow passage communicates with an inlet of the jacket or an outlet of the jacket. The heat transfer member may contact an inner wall surface of a part of the engine that defines the jacket, and may contact an inner wall surface of the housing that defines the flow passage. 
     The housing may be made of a material which is lower in heat conductivity than that of the heat transfer member. 
     The flow control valve may be located outside of the engine. 
     The housing may include a valve storage part that accommodates the valve body therein. The heat transfer member may contact an inner wall surface of the housing to define an inner space of the valve storage part in which the valve body is accommodated. 
     The heat transfer member may be provided in a connection part between the jacket and the flow passage. The heat transfer member may extend in a flow direction of the coolant to define the flow passage and a part of the jacket. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure, together with additional objectives, features and advantages thereof, will be best understood from the following description, the appended claims and the accompanying drawings, in which: 
         FIG. 1  is a schematic diagram showing a cooling device for an engine, according to a first embodiment of the present disclosure; 
         FIG. 2  is a sectional schematic diagram showing a connection part between a cylinder head and a rotary valve for the cooling device according to the first embodiment; 
         FIG. 3  is a sectional schematic diagram showing a connection part between a cylinder head and a ball valve for a cooling device according to a second embodiment of the present disclosure; 
         FIG. 4  is a sectional schematic diagram showing a connection part between a cylinder head and a butterfly valve for a cooling device according to a third embodiment of the present disclosure; 
         FIG. 5  is a sectional schematic diagram showing a connection part between a cylinder head and a poppet valve for a cooling device according to a fourth embodiment of the present disclosure; 
         FIG. 6  is a schematic diagram showing a cooling device for an engine, according to a fifth embodiment of the present disclosure; 
         FIG. 7  is a schematic diagram showing a cooling device for an engine, according to a modification; and 
         FIG. 8  is a schematic diagram showing a cooling device for an engine, according to a modification. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the present disclosure will be described hereinafter referring to drawings. In the embodiments, a part that corresponds to a matter described in a preceding embodiment may be assigned with the same reference numeral, and redundant explanation for the part may be omitted. When only a part of a configuration is described in an embodiment, another preceding embodiment may be applied to the other parts of the configuration. The parts may be combined even if it is not explicitly described that the parts can be combined. The embodiments may be partially combined even if it is not explicitly described that the embodiments can be combined, provided there is no harm in the combination. 
     First Embodiment 
     A cooling device  1  of a first embodiment will be described with reference to  FIGS. 1 and 2 . The cooling device  1  includes a coolant circuit in which a coolant circulates to cool an internal combustion engine  2 , a pump  3  (water pump) that discharges the coolant, and a radiator  4  which cools the coolant via heat exchange with air. The coolant discharged from the pump  3  into the coolant circuit flows through the engine  2  and the radiator  4  to the pump  3 . For example, a coolant (e.g., Long Life Coolant) which contains ethylene glycol may be used as the coolant of the coolant circuit. 
     The engine  2  includes a cylinder head  6  and a cylinder block  7 , and the cylinder head  6  and the cylinder block  7  have a jacket  8  (water jacket) through which the coolant passes. In the present embodiment, the jacket  8  has an inlet  8 A through which the coolant flows into, and an outlet  8 B from which the coolant is discharged. The inlet  8 A is located in the cylinder block  7  and the outlet  8 B is located in the cylinder head  6 . Thus, the jacket  8  is a coolant passage extends from the cylinder block  7  through between cylinders of the engine  2  to the cylinder head  6 . 
     The pump  3  is disposed adjacent to the inlet  8 A of the jacket  8  to make the coolant circulate in the engine  2 . 
     The radiator  4  is a heat exchanger that cools the coolant discharged from the engine  2  via heat exchange with air. The coolant passed through and cooled by the radiator  4  is supplied to the jacket  8  by the pump  3 . 
     In the coolant circuit, a rotary valve  10  is arranged to control a flow rate of the coolant. In the present embodiment, the rotary valve  10  is connected to an outlet side of the jacket  8  so that an inside of the rotary valve  10  communicates with the outlet  8 B the jacket  8 . The rotary valve  10  may be used as an example of a flow control valve which controls a flow rate of the coolant flowing therethrough. The rotary valve  10  includes a housing  11  and a valve body  112  arranged in the housing  11 . The housing  11  made of resin includes a passage forming portion  115  that has an approximately cylindrical shape to have a flow passage  14  therein, and a flange portion  16  that extends radially outward from an outer surface of an end part of the passage forming portion  115 . The end part of the passage forming portion  115  is located on one side of the passage forming portion  115  in its axial direction. The passage forming portion  115  is arranged so that the flow passage  14  communicates with the outlet  8 B of the jacket  8 . The flange portion  16  is fixed to a surface of the cylinder head  6  by using a screw for example. 
     The passage forming portion  115  includes a cylindrical part  18  having a first cylindrical space therein with an axis of the first cylindrical space extending along a flow direction of the coolant in the flow passage  14 , and a valve storage part  19  having a second cylindrical space therein with an axis of the second cylindrical space extending perpendicular to the flow direction of the coolant in the flow passage  14 . The valve body  112  is arranged inside the valve storage part  19 . The valve body  112  has a bottomed cup-like shape, and rotates about an axis that is perpendicular to the axial direction of the passage forming portion  115 . A wall of the valve body  112  has a through hole  20  through which the coolant is capable of passing. Accordingly, by rotating the valve body  112  about its rotation axis, the flow passage  14  can be opened or closed. 
     In the present embodiment, the rotary valve  10  includes a heat transfer member  22  that contacts the engine  2  and contacts the valve storage part  19  of the housing  11  to transfer a heat from the engine  2  to the housing  11 . The valve storage part  19  is a part of the housing  11  that accommodates the valve body  112  therein. A size of the valve storage part  19  covers a movement range of the valve body  112 , in other words, the valve storage part  19  accommodates the valve body  112  even when the valve body  112  moves. 
     The heat transfer member  22  is made of a material, such as noble metal or steel, superior in heat conductivity for example. The heat transfer member  22  is arranged to contact an inner wall surface  23  of the cylinder head  6  and an inner wall surface  24  of the passage forming portion  115  of the housing  11 . Specifically, the heat transfer member  22  has a cylindrical shape along the axial direction of the passage forming portion  115 , and an outer periphery of the heat transfer member  22  contacts both the inner wall surface  23  of the cylinder head  6  and the inner wall surface  24  of the passage forming portion  115 . The transfer member  22  extends from a part of the inner wall surface  23  that defines the outlet  8 B of the jacket  8  to a part of the inner wall surface  24  located downstream of the valve body  112  in the flow direction of the coolant. Accordingly, the valve storage part  19  of the housing  11 , which accommodates the valve body  112 , is connected to the cylinder head  6  via the heat transfer member  22 . 
     As shown in  FIG. 2 , an inner peripheral surface of the heat transfer member  22  is flush with a part of the inner wall surface  23  of the cylinder head  6  that is located upstream of the heat transfer member  22  in the flow direction of the coolant. Accordingly, the heat transfer member  22  can be prevented from being a flow resistance to the coolant. 
     Effects of the present embodiment will be described. A combustion heat of the engine  2  can be transferred promptly to the valve storage part  19  through the heat transfer member  22  in the present embodiment. Even in a case where the coolant freezes around the valve body  112  inside the valve storage part  19 , the frozen coolant can be melted by the heat transferred from the engine  2  via the heat transfer member  22 . As a result, the valve body  12  can be made to be operable (movable) swiftly. Here, the frozen coolant includes a state (sherbet state) where liquid and solid states of the coolant are mixed. 
     The housing  11  is made of resin that is lower in heat conductivity than that of the heat transfer member  22 , and the heat transfer member  22  is located on an inner side of the passage forming portion  115 . Hence, the heat transferred from the engine  2  is difficult to be radiated to an outside of the housing  11 . Therefore, the heat transferred from the engine  2  can be utilized for melting the frozen coolant effectively. 
     Second Embodiment 
     A cooling device of a second embodiment will be described referring to 
       FIG. 3 . A part different from a part of the first embodiment will be described mainly in the second embodiment. A reference number same as that described in the first embodiment indicates the same structure in the second embodiment as that indicated by the reference number in the first embodiment. Thus, an explanation of a part assigned the reference number is referred to the first embodiment. In the second embodiment, the cooling device includes a ball valve  30  instead of the rotary valve  10  of the first embodiment, and the ball valve  30  may be used as an example of the flow control valve described above. The ball valve  30  includes a housing  11  having a passage forming portion  215 . The passage forming portion  215  has a cylindrical shape, and defines a flow passage  14  therein. A part of the passage forming portion  215  extending by a predetermined length in its axial direction is a valve storage part  19  that accommodates a valve body  212  therein. The valve body  212  has a spherical shape and is arranged in the valve storage part  19 . The valve body  212  has a through hole  26  extending through the valve body  212  in a direction perpendicular to a rotation axis of the valve body  212 . The valve body  212  rotates around the rotation axis thereof that is perpendicular to the axial direction of the passage forming portion  215 . By rotating the valve body  212 , the flow passage  14  can be opened or closed. Effects similar to those of the first embodiment can be obtained in the second embodiment. 
     Third Embodiment 
     A cooling device of a third embodiment will be described referring to  FIG. 4 . A part different from a part of the first embodiment will be described mainly in the second embodiment. A reference number same as that described in the first embodiment indicates the same structure in the third embodiment as that indicated by the reference number in the first embodiment. Thus, an explanation of a part assigned the reference number is referred to the first embodiment. In the third embodiment, the cooling device includes a butterfly valve  40  instead of the rotary valve  10  of the first embodiment, and the butterfly valve  40  may be used as an example of the flow control valve described above. The butterfly valve  40  includes a housing  11  having a passage forming portion  315 . The passage forming portion  315  has a cylindrical shape, and defines a flow passage  14  therein. A part of the passage forming portion  315  extending by a predetermined length in its axial direction is a valve storage part  19  that accommodates a valve body  312  therein. The valve body  312  has a platy shape and is arranged in the valve storage part  19 . The valve body  312  rotates around a rotation axis that is perpendicular to the axial direction of the passage forming portion  315 . By rotating the valve body  312 , the flow passage  14  can be opened or closed. Effects similar to those of the first embodiment can be obtained in the third embodiment. 
     Fourth Embodiment 
     A cooling device of a fourth embodiment will be described referring to  FIG. 5 . A part different from a part of the first embodiment will be described mainly in the fourth embodiment. A reference number same as that described in the first embodiment indicates the same structure in the fourth embodiment as that indicated by the reference number in the first embodiment. Thus, an explanation of a part assigned the reference number is referred to the first embodiment. In the fourth embodiment, the cooling device includes a poppet valve  50  instead of the rotary valve  10  of the first embodiment, and the poppet valve  50  may be used as an example of the flow control valve described above. The poppet valve  50  includes a housing  11  having a passage forming portion  415 . The passage forming portion  415  defines a flow passage  14  therein. The passage forming portion  415  includes a small diametrical part  15   a,  a large diametrical part  15   b  located downstream of the small diametrical part  15   a  in a flow direction of the coolant, and a step part  15   c  located between the small diametrical part  15   a  and the large diametrical part  15   b.  The small diametrical part  15   a  is smaller in diameter than the large diametrical part  15   b.  The step part  15   c  has a surface facing downstream in the flow direction of the coolant. The large diametrical part  15   b  accommodates therein a valve body  412  that is a poppet of the poppet valve  50 . In the fourth embodiment, the valve body  412  is operable to move by a predetermined length in an axial direction of the large diametrical part  15   b.  A part of the large diametrical part  15   b  extending by the predetermined length in the axial direction thereof is a valve storage part  19 . Thus, the valve body  412  is accommodated in the valve storage part  19  even when the valve body  412  is moving. The cooling device  50  includes a heat transfer member  22  provided along an inner wall surface  23  of a cylinder head  6  and along an inner wall surface  24  of the passage forming portion  415 . The heat transfer member  22  has a valve sheet  28  at a position corresponding to the step part  15   c  of the passage forming portion  415 , and the valve body  412  is movable in the axial direction of the large diametric part  15   b  to contact or be separated from the valve sheet  28 . When the valve body  412  contacts or is separated from the valve sheet  28 , the flow passage  14  is closed or opened. Effects similar to those of the first embodiment can be obtained in the fourth embodiment. 
     Fifth Embodiment 
     A cooling device  1   a  of a fifth embodiment will be described referring to  FIG. 6 . A part different from a part of the first embodiment will be described mainly in the fifth embodiment. A reference number same as that described in the first embodiment indicates the same structure in the fifth embodiment as that indicated by the reference number in the first embodiment. Thus, an explanation of a part assigned the reference number is referred to the first embodiment. In the cooling device  1   a  of the fifth embodiment, an inlet  8 A of a jacket  8  is provided in a cylinder block  7 , and outlets  8 B of the jacket  8  is provided respectively in the cylinder block  7  and a cylinder head  6 . Thus, a coolant flowing into the jacket  8  through the inlet  8 A splits into two flows in the cylinder block  7  as shown in  FIG. 6 . Subsequently, one of the two flows passes through the cylinder block  7  to flow out from the jacket  8  through the outlet  8 B provided in the cylinder block  7 , and the other of the two flows enters into the cylinder head  6  to pass through the cylinder head  6  and to flow out of the jacket  8  through the outlet  8 B provided in the cylinder head  6 . The outlets  8 B of the jacket  8  are respectively connected to rotary valves  10 , and each of the rotary valves  10  is same as that described in the first embodiment in structure. Effects similar to those of the first embodiment can be obtained also in the fifth embodiment. 
     Although the present disclosure has been fully described in connection with the preferred embodiments thereof with reference to the accompanying drawings, it is to be noted that various changes and modifications described below will become apparent to those skilled in the art. In the above-described embodiments, the flow control valve is provided on the outlet side of the jacket  8 . However, the flow control valve may be provided on an inlet side of the jacket  8  as shown in  FIG. 7 , or the flow control valves may be provided respectively on the outlet side and the inlet side of the jacket  8  as shown in  FIG. 8 . In the above-described embodiments, the heat transfer member  22  is provided inside the housing  11 , but may be provided outside the housing  11 . In other words, the heat transfer member  22  may be arranged to connect an outer periphery of the housing  11  and an outer wall surface of the cylinder block  7  or an outer wall surface of the cylinder head  6 . In the above-described first embodiment, the heat transfer member  22  contacts both the valve storage part  19  of the housing  11  and a part of the housing  11  other than the valve storage part  19 . For example, the heat transfer member  22  contacts also the cylindrical part  18 . However, the heat transfer member  22  may contact only the valve storage part  19 . Thus, the heat transfer member  22  may be required to contact at least the valve storage part  19 . 
     Additional advantages and modifications will readily occur to those skilled in the art. The disclosure in its broader terms is therefore not limited to the specific details, representative apparatus, and illustrative examples shown and described.