Patent Publication Number: US-2018051621-A1

Title: Engine system having coolant control valve

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based on and claims the benefit of priority to Korean Patent Application No. 10-2016-0106269 filed on Aug. 22, 2016 with the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to an engine system having a coolant control valve unit which improves a cooling efficiency and consumption efficiency of the engine by respectively controlling a coolant supplied from a cylinder head and a cylinder block of the engine. 
     BACKGROUND 
     An engine generates a rotation force by combusting fuel, and the remaining energy from the combustion of the fuel is exhausted as heat energy. In particular, a coolant absorbs heat energy while circulating through the engine, a heater, and a radiator, and discharges the absorbed heat energy to the outside. 
     When a coolant temperature of the engine is low, viscosity of the oil is increased so that a frictional force is increased, fuel consumption is increased, and a temperature of an exhaust gas is slowly increased so that time for activation of a catalyst is extended, and accordingly, quality of the exhaust gas may be deteriorated. Furthermore, time for normalization of operation of the heater is extended so that a passenger or a driver may feel cold. 
     When the coolant temperature of the engine is excessively high, knocking occurs, and ignition timing needs to be adjusted for suppression of the occurrence of knocking, thereby causing operation deterioration. In addition, when a temperature of lubricant is excessively high, lubrication performance may be deteriorated. 
     Thus, one integrated flow control valve that controls several cooling elements is applied to maintain a temperature of the coolant at a specific portion of the engine to be high and a temperature of the coolant at other portions to be low. 
     Further, coolant separation cooling method controlling coolant passing through a cylinder head and coolant passing through a cylinder block respectively is introduced, and the cylinder head is controlled by relatively low temperature and the cylinder block is controlled by relatively high temperature, therefore, fuel consumption may be reduced and cooling efficiency may be improved. 
     Meanwhile, a coolant temperature sensor sensing temperature of the coolant exhausted from the cylinder head is disposed. To improve temperature sensitivity of the coolant temperature sensor, a bypass hole is formed at a valve so that the coolant flows in a state that the valve is closed, however, a deviation between real temperature and sensing temperature of the coolant may be increased because of distance difference between the bypass hole and the coolant temperature sensor. 
     The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure 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 has been made in an effort to provide an engine system having a coolant control valve unit having advantages of being capable of improving precision of controlling by reducing deviation between a sensing temperature sensed from a coolant temperature sensor and real coolant temperature. 
     As described above, an engine system having a coolant control valve unit according to an exemplary embodiment of the present disclosure includes a valve housing in which a passage having a coolant supplied from one side of the passage and exhausted to another side of the passage is formed, a valve for rotating with reference to a rotation center shaft, wherein a closing portion closing the passage according to a rotation position of the valve and an opening portion opening the passage are formed in the valve with a predetermined interval in a rotation direction, and an actuator for rotating the valve with reference to the rotation center shaft, and a controller for controlling the actuator according to driving condition, and a bypass passage penetrating the closing portion of the valve may be formed in a state that the closing portion closes the passage. 
     An exterior circumference of the closing portion of the valve may be formed in a sphere shape, and the opening portion may be formed in a circular shape along a circumference of the passage. 
     The engine system having a coolant control valve unit according to an exemplary embodiment of the present disclosure may further include a connecting member integrally connecting an upper portion with a lower portion of the valve, and the opening portion may be formed between the closing portion and the connecting member. 
     The engine system having a coolant control valve unit according to an exemplary embodiment of the present disclosure may further include a pipe member integrally connecting a lower end portion of the connecting member with an inner side surface of the closing portion, and the bypass passage may be formed at a center portion of the pipe member. 
     The engine system having a coolant control valve unit according to an exemplary embodiment of the present disclosure may further include a coolant temperature sensor disposed at the valve housing to sense a temperature of a coolant passing through an inlet of the pipe member connected with the lower end portion of the connecting member. 
     A head coolant inlet that a coolant is supplied from a cylinder head of the engine and a block coolant inlet that the coolant is supplied from a cylinder block of the engine may be formed at the valve housing, and the valve may control the coolant supplied from the head coolant inlet. 
     The engine system having a coolant control valve unit according to an exemplary embodiment of the present disclosure may further include a block thermostat operating according to a coolant temperature to open or close the second passage. 
     The coolant supplied from the head coolant inlet and the block coolant inlet may be respectively distributed to a heater core conducting heat exchange with indoor air, an oil cooler conducting heat exchange with oil circulating the engine, and a radiator conducting heat exchange with outdoor air. 
     The engine system having a coolant control valve unit according to an exemplary embodiment of the present disclosure may further include a radiator thermostat controlling the coolant operated by the controller and supplied to the radiator according to temperature of the coolant exhausted from the radiator. 
     The coolant exhausted from the heater core, the oil cooler, and the radiator may be pumped to the cylinder block of the engine, and the pumped coolant may circulate through the cylinder head and the cylinder block. 
     An engine system having a coolant control valve unit according to an exemplary embodiment of the present disclosure may include a valve housing including, at one side thereof, a head coolant inlet that a head coolant is supplied from a cylinder head of the engine and a block coolant passage that a block coolant is supplied from a cylinder block of the engine, wherein a first passage connected with the head coolant inlet and a second passage connected with the block coolant passage are formed in the valve housing; a mixing housing disposed at another side of the valve housing, in which the coolant passing through the first and second passages gather, and configured to distribute the coolant to respective coolant demanding elements; a valve for rotating with reference to a rotation center shaft, wherein a closing portion closing the first passage according to a rotation position of the valve and an opening portion opening the passage are formed in the valve with a predetermined interval in a rotation direction; a block thermostat operating according to a coolant temperature to open or close the second passage; an actuator for rotating the valve with reference to the rotation center shaft; and a controller for controlling the actuator according to driving conditions, a bypass passage may be formed to penetrate the closing portion of the valve in a state that the closing portion closes the passage. 
     According to the exemplary embodiments of the present disclosure, the closing portion and the opening portion are formed in a predetermined interval in a rotation direction at the valve, one end portion of the pipe member is integrally connected with the closing portion, the bypass passage is formed along the center portion of the pipe member, and the coolant temperature sensor is disposed at the inlet of the other end of the pipe member. Therefore, accuracy of sensing the coolant temperature may be improved. 
     Further, the pipe member is integrally formed at the closing portion of the valve, and the coolant penetrates easily through the bypass passage in a state that the closing portion of the valve closes the coolant passage. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram illustrating a coolant flow in an engine system having a coolant control valve unit according to an exemplary embodiment of the present disclosure. 
         FIG. 2  is a schematic perspective view of a coolant control valve unit according to an exemplary embodiment of the present disclosure. 
         FIG. 3  is a perspective view of a valve disposed at a coolant control valve unit according to an exemplary embodiment of the present disclosure. 
         FIG. 4  is a front view of a valve disposed at a coolant control valve unit according to an exemplary embodiment of the present disclosure. 
         FIG. 5  is a graph showing effect of an engine system having a coolant control valve unit according to an exemplary embodiment of the present disclosure. 
       
         
           
             
                 
               
                 
                     
                 
                 
                   &lt;Description of symbols&gt; 
                 
                 
                     
                 
               
              
                 
                     
                 
              
             
             
                 
                 
                 
              
                 
                     
                   100: coolant control valve unit 
                   102: valve housing 
                 
                 
                     
                   105: cylinder head 
                   115: oil cooler 
                 
                 
                     
                   120: heater core 
                   125: radiator thermostat 
                 
                 
                     
                   130: radiator 
                   140: coolant pump 
                 
                 
                     
                   110: cylinder block 
                   200: coolant temperature sensor 
                 
                 
                     
                   210: block thermostat 
                   215: block coolant inlet 
                 
                 
                     
                   220: head coolant inlet 
                   230: actuator 
                 
                 
                     
                   250: valve 
                   252: mixing housing 
                 
                 
                     
                   300: closing portion 
                   302: rotation center shaft 
                 
                 
                     
                   310: opening portion 
                   312: connecting member 
                 
                 
                     
                   320: pipe member 
                   325: bypass passage 
                 
                 
                     
                     
                 
              
             
           
         
       
     
    
    
     DETAILED DESCRIPTION 
     An exemplary embodiment of the present disclosure will hereinafter be described in detail with reference to the accompanying drawings. 
       FIG. 1  is a schematic diagram illustrating a coolant flow in an engine system having a coolant control valve unit according to an exemplary embodiment of the present disclosure. 
     Referring to  FIG. 1 , the engine system includes a cylinder head  105 , a cylinder block  110 , a coolant control valve unit  100 , a heater core  120 , an oil cooler  115 , a radiator  130 , a radiator thermostat  125 , and a coolant pump  140 . 
     Further, the engine system includes a controller (not shown) controlling the coolant control valve unit  100 , the radiator thermostat  125 , and the coolant pump  140 , and the controller may respectively control the coolant control valve unit  100 , the radiator thermostat  125 , and the coolant pump  140 . Further, unexplained portions refer to known techniques. 
     Coolant pumped by the coolant pump  140  is pumped to one side of the cylinder block  110 , a portion of the pumped coolant passes the cylinder block  110 , and the remains are distributed to the cylinder head  105 . 
     The coolant passing the cylinder head  105  and the cylinder block  110  is respectively supplied to both sides of the coolant control valve unit  100 , and the coolant control valve unit  100  distributes the supplied coolant to the heater core  120 , the oil cooler  115 , and the radiator  130 . Here, the coolant control valve unit  100  may respectively control the head coolant passing the cylinder head  105  and the block coolant passing the cylinder block  110 . 
     The radiator thermostat  125  may operate by the controller or the coolant temperature to control the coolant passed the radiator, and the coolant passed the heater core  120 , the oil cooler  115  and the radiator  130  recirculates to intake side of the coolant pump  140  again. The structures and functions of the heater core  120 , the oil cooler  115  and the radiator  130  refer to known technologies. 
       FIG. 2  is a schematic perspective view of a coolant control valve unit according to an exemplary embodiment of the present disclosure. 
     Referring to  FIG. 2 , the coolant control valve unit  100  includes a valve housing  102 , an actuator  230 , a valve  250 , a head coolant inlet  220 , a block coolant inlet  215 , a coolant temperature sensor  200 , and a block thermostat  210 . 
     On the front surface of the valve housing  102 , the head coolant inlet  220  that the coolant is supplied from the cylinder head  105  and the block coolant inlet  215  that the coolant is supplied from the cylinder block  110  are respectively formed, and a mixing housing  252  that the coolant gathers is disposed at the opposing side of the block coolant inlet  215 . 
     The coolant gathered in the mixing housing  252  is distributed to the heater core  120 , the oil cooler  115 , and the radiator  130 , as described above. 
     The head coolant supplied through the head coolant inlet  220  is gathered in the mixing housing  252  through a first passage formed in the valve housing  102 , and the block coolant supplied through the block coolant inlet  215  is gathered in the mixing housing  252  through a second passage formed in the valve housing  102 . 
     The valve  250  is disposed at the first passage, and the valve  250  rotates by the actuator  230  to open and close the first passage. Further, the block thermostat  210  is disposed at the second passage, and the block thermostat  210  operates by the coolant temperature to open and close the second passage. 
     The coolant temperature sensor  200  is disposed at the coolant inlet of the valve  250 . The coolant temperature sensor  200  penetrates side surface of the valve housing  102  to protrude toward inside of the head coolant inlet  220 . 
     The coolant temperature according to an exemplary embodiment of the present disclosure is disposed at the inlet of the bypass passage  325  of the valve  250  to improve performance of sensing the coolant temperature. Hereinafter, the structure of the valve  250  will be described in detail referring to  FIG. 3  and  FIG. 4 . 
       FIG. 3  is a perspective view of a valve disposed at a coolant control valve unit according to an exemplary embodiment of the present disclosure, and  FIG. 4  is a front view of a valve disposed at a coolant control valve unit according to an exemplary embodiment of the present disclosure. 
     Referring to  FIG. 3  and  FIG. 4 , the valve  250  includes a virtual rotation center shaft  302 , a closing portion  300 , an opening portion  310 , a connecting member  312 , and a pipe member  320 . 
     The valve  250  rotates with reference to the rotation center shaft  302 , and the closing portion  300  is formed at a rear side with reference to the rotation center shaft  302 . Further, the opening portion  310  is formed in a predetermined interval with the closing portion  300  in the rotation direction. Here, the closing portion  300  and the opening portion  310  are formed by rotation difference of about 90 degrees. 
     The connecting member  312  integrally connects the upper portion and the lower portion of the valve  250 , the opening portion  310  is formed between the connecting member  312  and the closing portion  300 , and the opening portion  310  is formed as a circular shape corresponding to the shape of the first passage. 
     The pipe member  320  is disposed at the lower portion of the valve  250  by a distance with the rotation center shaft  302  in a vertical direction, and the bypass passage  325  is formed at the center portion of the pipe member  320 . 
     More particularly, the front end portion of the pipe member  320  is integrally connected with the lower end portion of the connecting member  312 , the rear end portion of the pipe member  320  is integrally connected with the closing portion  300 , and the bypass passage  325  is formed at the center portion of the pipe member  320 . 
     In a state that the closing portion  300  closes the first passage, the coolant exhausted from the cylinder head  105  circulates through the head coolant inlet  220 , the inlet of the pipe member  320 , and bypass passage  325  to the mixing housing  252 . Further, the coolant temperature sensor  200  is disposed at the inlet of the pipe member  320  to improve performance of sensing coolant temperature. 
       FIG. 5  is a graph showing effect of an engine system having a coolant control valve unit according to an exemplary embodiment of the present disclosure. 
     Referring to  FIG. 5 , the horizontal axis indicates a time, and the vertical axis indicates a coolant temperature. 
     The coolant temperature sensor output value in the open state and the direct measuring value of the coolant in the head are nearly similar. The coolant temperature sensor output value is slightly smaller than the direct measuring value of the coolant in the head. 
     Further, the coolant sensor output value in the close state and the direct measuring value of the coolant in the head maintain high value in the open state, and the coolant temperature sensor output value in the close state increases to follow the direct measuring value of the coolant in the head. 
     In other words, difference between the coolant sensor output value in the close state and the direct measuring value of the coolant in the head decreases than the difference of prior art. 
     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. On the contrary, it is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.