Patent Publication Number: US-11047271-B2

Title: Socket module of compression release type engine brake and operating method of engine brake using thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to and the benefit of Korean Patent Application No. 10-2019-0123903, filed on Oct. 7, 2019, the entire contents of which are incorporated herein by reference. 
     FIELD 
     The present disclosure relates to a socket module of a compression release type of engine brake, and an operation method of the engine brake using the same. 
     BACKGROUND 
     The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. 
     In general, a brake system of an internal combustion engine vehicle uses a hydraulic pressure type of brake, but the engine brake is used to prevent premature abrasion of a brake pad during downhill driving or frequent sudden stops. 
     The compression release type of engine brake device, which is a type of engine brake, temporarily opens an exhaust valve near a compress top dead center of a piston during the basic four strokes of the engine, i.e., exhausts compressed air in a cylinder out of the cylinder to thereby obtain a braking effect by inducing a pumping loss of an expansion stroke. 
     In a compression release type of engine brake according to a conventional art, a socket module is applied between a valve bridge connected with a pair of exhaust valves, and an exhaust rocket arm. 
     In the socket module, the brake piston is provided inside the housing where the brake oil is introduced, and when the engine brake is operated, the brake piston moves downward to eliminate the gap between the exhaust rocker arm and the exhaust cam, thereby forcing the exhaust valve to be opened at the end of the compression stroke. 
     The exhaust valve is opened at the end of the compression stroke by the socket module to add braking force to the vehicle. However, we have discovered that once the engine brake oil is introduced into the socket module, it is not exhausted, and thus the valve may be opened more by oil pressure formed in the socket module. 
       FIG. 11  is a graph that shows a valve lift displacement amount occurring in use of a compression release type of engine brake according to a conventional art. 
     As shown in  FIG. 11 , there is a possibility of occurrence of a contact A between an exhaust valve and an engine piston. 
     When a compression release type of engine brake with a reset bracket is provided on one side of the socket module, the reset bracket must be applied to the outside of the reset module as well. Therefore, we have found that there is a drawback in which the overall size increases. 
     In addition, the socket module applied to the compress relaxes type of engine brake according to conventional art often causes a phenomenon in which the brake piston detaches from the housing when transferring or assembles parts, causing quality problems. 
     The above information disclosed in this Background section is only for enhancement of understanding of the background of the present disclosure, and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. 
     SUMMARY 
     The present disclosure provides a socket module of a compression release type of engine brake that can automatically initialize a pressure inside the socket module by automatically exhausting the engine brake oil that has been introduced into the socket module during engine brake operation, and an operation method of the engine brake using the same. 
     In addition, an exemplary form of the present disclosure applies a stopper that limits the position of the brake valve, so that the brake valve can be prevented from being detached from the housing with a simple structure. 
     In one form of the present disclosure, a socket module for a compression release type of engine brake is provided between an exhaust rocker arm rotating with respect to a rocker arm shaft and a valve bridge in contact with an exhaust valve of an engine. In particular the socket module incudes: a housing in which an inlet through which brake oil is introduced is formed, a brake piston mounting portion is formed, and a reset member mounting portion configured to communicate with the brake piston mounting portion is formed; a brake piston that is provided to be movable in the brake piston mounting portion; a stopper disposed on one side of an inner space of the housing to limit the moving position of the brake piston; and a reset member provided in the reset member mounting portion and configured to discharge brake oil by selectively contacting a push pin coupled to an upper portion of a cylinder head. 
     The socket module may further include at least one upper protrusion and a lower protrusion formed on each exterior surface of the upper and lower portions of the brake piston so that movement of the brake piston is restricted by the stopper. 
     A stopper mounting portion in which the stopper is mounted may be formed in the housing. 
     The at least one upper protrusion may include a plurality of upper protrusions, and upper protrusions of the plurality of upper protrusions may be spaced apart from each other along a circumference of the exterior surface of the upper portion of the brake piston, and the upper protrusions may enclose a certain area of an upper surface and a side surface of the upper protrusion and be connected to an upper edge of the brake piston. 
     An upper passage may be formed between the upper protrusions. 
     The stopper may include a head portion and a body portion, the body portion may be mounted through the stopper mounting portion, and an end of the body portion may be protruded into the brake piston mounting portion to position between the upper and lower protrusions. 
     The housing may further include a rounded mounting groove protruded upward from a upper center of the housing where an adjusting screw mounted to one end of the exhaust rocker arm is mounted. 
     The reset member mounting portion may include a first passage connected with the brake piston mounting portion through a first outlet and a second passage configured to discharge brake oil and connected with the first passage through a slanted surface, wherein a diameter of the second passage is smaller than a diameter of the first passage. 
     The brake piston may be inserted into the brake piston mounting portion, and a receiving groove is formed in an upper portion of the brake piston. 
     The socket module may further include a check valve that is disposed in the receiving groove, and configured to open and close the inlet by being elastically supported by a check spring. 
     The reset member may include a reset valve configured to move in the reset member mounting portion and open and close an outlet and a reset spring configured to elastically support a lower portion of the reset valve, and wherein when the push pin pushes the reset valve brake oil is discharged. 
     The reset valve may have a flow path groove that is concave inward from an upper exterior circumference of the reset valve, and an upper portion of the reset valve may be locked by a slanted surface such that an upper portion of the reset valve does not escape in a downward direction. 
     A method for operating a compression release engine brake using a socket module provided between an exhaust rocker arm and a valve bridge, where the socket module includes a housing including an inlet, a brake piston mounting portion and a reset member mounting portion, a brake piston, and a reset member, the method may include: providing brake oil to the brake piston mounting portion through the inlet of the housing; descending the brake piston by hydraulic pressure of the brake oil and rotating the exhaust rocker arm in a first direction relative to a rocker arm shaft such that a roller and an exhaust cam of the exhaust rocker arm contact to each other; contacting the exhaust cam to a brake cam lobe while rotating and pressing the valve bridge by the exhaust rocker arm while rotating in a second direction relative to the rocker arm shaft such that an exhaust valve is opened; and pushing a reset valve by a push pin as the exhaust rocker arm rotates such that an outlet is opened. 
     The providing the brake oil to the brake piston mounting portion may include introducing the brake oil into a flow path formed in an adjusting screw, and opening a check valve such that the brake oil is introduced into the brake piston mounting portion through the inlet. 
     The descending the brake piston may include: raising the check valve by the restoring force of the check spring to close the inlet, and at the same time, lowering the position of the brake piston so that the upper protrusion contacts the stopper and the position is limited, and supporting the brake piston by the valve bridge such that the housing is lifted, and the roller and the exhaust cam contact each other while the exhaust rocker arm rotates in the first direction relative to the rocker arm shaft. 
     In contacting the exhaust cam to the brake cam lobe, the exhaust rocker arm may rotate in the second direction in a section where the brake cam lobe and the roller contact each other while the exhaust cam rotates, and the exhaust valve connected to the valve bridge may be opened while the valve bridge is pressed in a downward direction. 
     In pushing the reset valve, the reset valve may move upward by the push pin disposed corresponding to the reset valve while the exhaust cam rotates, and a first outlet and a second outlet are opened through a flow path groove formed in the reset valve, and the brake oil introduced into the brake piston mounting portion may be discharged through the first outlet and the second outlet. 
     After pushing the reset valve by the push pin, the brake oil may be discharged, and the reset valve moves upward by a restoring force of a reset spring that elastically supports the reset valve. 
     The compression release type of engine brake socket module according to an exemplary form of the present disclosure and the engine brake operation method of the engine brake using the same may be provided with a stopper for limiting a position of a brake valve, thereby preventing the brake valve from being separated from the housing with simplified scheme. 
     The compression release type of engine brake socket module according to an exemplary form of the present disclosure and the engine brake operation method of the engine brake using the same automatically exhaust the brake oil introduced into the housing during engine brake operation by being provided with a reset member such that It is possible to prevent the exhaust valve from contacting the engine piston. 
     In addition, effects obtained or predicted by the exemplary form of the present disclosure are disclosed directly or implicitly in a detailed description of an exemplary form of the present disclosure. That is, various effects predicted according to an exemplary form of the present disclosure will be disclosed in a detailed description to be described later. 
     Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       DRAWINGS 
       In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which: 
         FIG. 1  is a schematic diagram of a basic four-stroke cycle of an engine; 
         FIG. 2  is a schematic diagram of an engine cycle for description of a compression release type of engine brake; 
         FIG. 3  is a schematic diagram of the compression release type of engine brake; 
         FIG. 4  is a perspective view of the socket module of the compression release type of engine brake; 
         FIG. 5  is a cross-sectional view of  FIG. 4 , taken along the line A-A; 
         FIG. 6  is a perspective view of a brake piston applied to the compression release type of engine brake; 
         FIG. 7  to  FIG. 10  sequentially illustrate an operation of the compression release type engine brake; and 
         FIG. 11  is a graph that shows a valve lift displacement amount occurring in use of a general compression release type of engine brake. 
     
    
    
     The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
     DETAILED DESCRIPTION 
     The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features. 
     The present disclosure will be described more fully hereinafter with reference to the accompanying drawings, in which exemplary forms of the present disclosure are shown. As those skilled in the art would realize, the described forms may be modified in various different ways, all without departing from the spirit or scope of the present disclosure. 
     In the following description, dividing names of components into first, second, and the like is to divide the names because the names of the components are the same as each other, and an order thereof is not particularly limited. 
       FIG. 1  is a schematic diagram of a basic four-stroke cycle of an angle, and  FIG. 2  is a schematic diagram of an engine cycle for description of a compression release type of engine brake according to an exemplary form of the present disclosure. 
     In general, the engine brake may be applied to prevent the vehicle from causing premature wear of the brake pads applied to the foot brake when driving downhill or when frequently stopping suddenly. 
     The compression release type of engine brake is actuated in one of the four basic strokes of the engine, and opens an exhaust valve at the end of a compression stroke so that the engine can perform its braking function. 
     Referring to  FIG. 1 , a vehicle engine is driven by repeating a four-stroke cycle of intake, compression, combustion, and exhaust when driving. 
     As shown in  FIG. 2 , the compression release type of engine brake temporarily opens an exhaust valve at the end of the compression stroke, that is, near a top dead center of the piston, to exhaust compressed air in a cylinder to the outside the cylinder, thereby acquiring a braking effect by inducing a pumping loss in the expansion stroke. 
     For this, the compression release type of engine brake according to the exemplary form of the present disclosure may be formed as follows. 
       FIG. 3  is a schematic diagram of the compression release type of engine brake according to the exemplary form of the present disclosure. 
     Referring to  FIG. 3 , in the compression release type engine brake, a rocker arm shaft  3  is inserted into an exhaust rocker arm  1  such that the exhaust rocker arm  1  rotates with respect to the rocker arm shaft  3 , a roller  5  is mounted to one end of the exhaust rocker arm  1 , and an adjusting screw  7  is mounted to the other end of the exhaust rocker arm  1 . 
     The roller  5  is formed to contact or not contact an exhaust cam  20  installed on a camshaft. 
     The adjusting screw  7  is mounted to the other end of the exhaust valve  10  and is thus connected with a valve bridge  11  through a socket module  30  provided at a lower end thereof. 
     The valve bridge  11  is connected to the exhaust valve  10 , and the exhaust valve  10  may be provided as a pair. 
     In addition, the exhaust cam  20  may be divided into a brake cam lobe section and a main cam lobe section according to a profile, and the brake cam lobe section and the main cam lobe section may be implemented by forming a brake cam lobe  23  and a main cam lobe  25  on the exhaust cam shaft  21 . 
     The main cam lobe  25  may implement the exhaust stroke by contacting the roller  5 , and the brake cam lobe  23  may open the exhaust valve  10  by contacting the roller  5  when the engine brake is operated. 
     In addition, a bias spring (not shown) is mounted to the exhaust rocker arm  1 , and the bias spring lifts one end of the exhaust rocker arm  1 , which corresponds to the roller  5 , and the same time, provides an elastic force in a direction in which the other end of the exhaust rocker arm  1 , which corresponds to the adjusting screw  7 , to be closely attached to the valve bridge  11 . 
     Accordingly, in a state before the engine brake operation (in the basic engine stroke), the roller  5  maintains a distance with the brake cam lobe  23  of the exhaust cam  20 , and, in the exhaust stroke, the roller  5  is pushed upward only by the main cam lobe  25  of the exhaust cam  20 . 
     That is, when brake oil for operation of the engine brake is not supplied, a gap is formed between the roller  5  provided at the other end of the exhaust rocker arm  1  and the exhaust cam  20  and thus the brake cam lobe  23  of the exhaust cam  20  and the roller  5  do not contact each other, thereby causing the engine brake not to work. 
     On the other hand, when the engine brake oil is supplied to operate the engine brake, the socket module  30  lifts the other side of the exhaust rocker arm  1  up such that the roller  5  and the exhaust cam  20  are in constant contact, and thus, at the end of the compression stroke, the exhaust rocker arm  1  is operated by the brake cam lobe  23  of the exhaust cam  20 , so that the braking effect can be obtained. 
     The socket module  30  is applied between the exhaust rocker arm  1  and the valve bridge  11 . 
       FIG. 4  is a perspective view of the socket module of the compression release type of engine brake according to an exemplary form of the present disclosure, and  FIG. 5  is a cross-sectional view of  FIG. 4 , taken along the line A-A.  FIG. 6  is a perspective view of a brake piston applied to the compression release type of engine brake according to an exemplary form of the present disclosure. 
     Referring to  FIG. 4  to  FIG. 6 , the socket module  30  of the compression release type of engine brake includes a housing  40 , a brake piston  70 , a stopper  90  and a reset member  100 . 
     The housing  40  includes a mounting portion  41  that protrudes upward from a center of an upper center thereof. 
     The mounting portion  41  includes a rounded mounting groove  41   a  provided therein such that the adjusting screw  7  is mounted thereto. 
     An inlet  43  connected with the mounting groove  41   a  is formed at a lower center of the mounting portion  41 . 
     In addition, a brake piston mounting portion  45  is formed at a lower side of the inlet  43 . 
     An upper end of the brake piston mounting portion  45  is connected with the inlet  43  inside the housing  40 , and a lower end of the brake piston mounting portion  45  is opened. 
     A stopper mounting portion  47  is formed on one side of the brake piston mounting portion  45 . 
     The stopper mounting portion  47  may be formed long in the left and right directions. 
     The outlet  49  is formed to the other side of the brake piston mounting portion  45 . 
     A reset member mounting portion  50  is formed in a vertical direction on the outlet  49 , and the reset member mounting portion  50  includes a first passage  50   a  and a second passage  50   b , each having a different diameter. 
     The first passage  50   a  is communicated with a first outlet  49   a  that is connected with the brake piston mounting portion  45 . 
     An upper portion of the first passage  50   a  may be closed by a cap  60 . 
     The second passage  50   b  is provided at a lower side of the first passage  50   a  and connected with the first passage  50   a  through a slanted surface  51 , and a diameter of the second passage  50   b  is smaller than that of the first passage  50   a.    
     A second outlet  49   b  that penetrates side surfaces of the housing  40  is connected at one side of the second passage  50   b.    
     The brake piston  70  and the reset member  100  are inserted into the housing  40 . 
     The brake piston  70  is movably provided in the brake piston mounting portion  45 , and is connected with the valve bridge  11 . 
     Referring to  FIG. 6 , the brake piston  70  is formed in a shape of a cylinder as a whole, and a receiving groove  71  that is concave downward is formed in the lower portion of the upper central portion. 
     A check valve  80  that opens and closes the inlet  43  is disposed in the receiving groove  71 . 
     The check valve  80  is elastically supported by a check spring  81  that is mounted to a center of the receiving groove  71  to open and close the inlet  43  while vertically driving. 
     An upper protrusion  73  and a lower protrusion  75  are formed on the exterior surfaces of the upper and lower parts of the brake piston  70 . 
     The upper protrusion  73  is formed in a plurality, and is spaced apart each other along the circumference, enclosing a certain area of the upper and side surfaces connected to the upper edge of the brake piston  70 . 
     The upper protrusion  73  may be formed to be spaced apart at regular intervals along the circumference. 
     The lower protrusion  75  is protruded along the lower side of the brake piston  70 . 
     An upper passage  74  is formed between each upper protrusion  73  so that the oil is easily exhausted through the outlet  49 . 
     That is, the oil flowed into the inlet  43  is exhausted through the outlet  49  through the space, that is the upper passage  74 , between the upper protrusion  73  and the lower protrusion  75  when exhausted. 
     The brake piston  70  operates in a vertical direction along the brake piston mounting portion  45  by brake oil introduced into the housing  40 . 
     At this time, the position of the brake piston  70  in the up and down direction is regulated by the stopper  90 , and the stopper  90  is mounted through the stopper mounting portion  47  of the housing  40 . 
     The stopper  90  includes a head portion  91  and a body portion  93 . 
     The body portion  93  is integrally formed with the head portion  91  and inserted into the stopper mounting portion  47 . 
     The stopper  90  is mounted so that an end of the body portion  93  is protruded into the brake piston mounting portion  45  at a position between the upper and lower protrusions  73  and  75 . 
     Since the stopper  90  is positioned between the upper protrusion  73  and the lower protrusion  75  of the brake piston  70 , the stopper is configured to limit the position of the brake piston  70 . 
     The stopper  90  can adjust the insert length of the body portion  93  in the form of a screw. 
     The reset member  100  is inserted to be vertically operated through the reset member mounting portion  50  of the housing  40 . 
     The reset member  100  includes a reset valve  110  that opens and closes the first and second outlets  49   a  and  49   b  of the housing  40  by being inserted into the reset member mounting portion  50 . 
     A flow path groove  111  that is concave inward is formed at an exterior circumference of an upper side of the reset valve  110 . 
     An upper end of the reset valve  110  is supported by being locked by the slanted surface  51  formed between the first passage  50   a  and the second passage  50   b  and thus supported so as to not escape in the downward direction. 
     In one form, a diameter of the upper end of the reset valve  110  is larger than a portion of the reset valve  110  inserted into the second passage  50   b  corresponding to the first passage  50   a.    
     The reset valve  110  is provided to be movable in a vertical direction by a reset spring  120  that elastically supports a lower end of the reset valve  110  from the outside the housing  40 . 
     In a state that the reset valve  110  is inserted in the reset spring  120 , a lower end of the reset spring  120  is fixed by a spring pin  121  mounted on the lower portion of the reset valve  110 . 
     Here, the reset valve  110  is operated by a push pin  130  (refer to  FIG. 3 ) that is mounted to one side of a cylinder head S. 
     The push pin  130  may be mounted to a top surface of the cylinder head S. A method of operating the engine brake using the socket module  30  configured as described above is as follows. 
       FIG. 7  to  FIG. 10  sequentially illustrate an operation of the compression release type engine brake according to an exemplary form of the present disclosure. 
     Referring to  FIG. 7 , when the engine brake is operated, the brake oil flows through a flow path inside the adjusting screw  7  to the inlet  43  of the housing  40 . 
     Then, the check valve  80  that opens and closes the inlet  43  descends to open the inlet  43  and then is mounted inside the receiving groove  71 . 
     Referring to  FIGS. 8A and 8B , when brake oil is introduced into the brake piston mounting portion  45 , the brake piston  70  descends by a hydraulic pressure and, at the same time, the check valve  80  closes the inlet  43  by an elastic force of the check spring  81  such that the brake piston mounting portion  45  is closed and sealed. 
     Here, the position of the brake piston  70  is limited by the upper protrusion  73  and stopper  90 . 
     In this case, as the brake piston  70  relatively descends, the exhaust rocker arm  1  rotates relative to the rocker arm shaft  3 , and the roller  5  of the exhaust rocker arm  1  contacts the exhaust cam  20 . 
     Subsequently, when the exhaust cam  20  rotates and thus the brake cam lobe  23  of the exhaust cam  20  and the roller  5  contact each other, an end portion of the exhaust rocker arm  1 , corresponding to the roller  5 , is lifted upward and rotates with reference to the rocker arm shaft  3  by the protruded brake cam lobe  23 . 
     Due to such an operation, the valve bridge  11  is pressed downward and the exhaust valve  10  is opened. That is, at the end of the compression stroke, that is, near the top dead center of the piston, the exhaust valve  10  is temporarily opened to exhaust the compressed air in the cylinder out of the cylinder, thereby inducing a pumping loss of the expansion stroke to obtain a braking effect. 
     Referring to  FIG. 9 , as the exhaust rocker arm  1  rotates, the reset valve  110  contacts the push pin  130  such that the reset valve  110  moves upward. 
     In this case, the first outlet  49   a  and the second outlet  49   b  are opened through the flow path groove  111  of the reset valve  110 . 
     The brake oil introduced into the brake piston mounting portion  45  is exhausted through the first outlet  49   a  and the second outlet  49   b.    
     Referring to  FIG. 10 , when the brake oil in the housing  40  is completely exhausted, the brake piston  70  moves upward and the reset valve  110  automatically returns to an initial state such that the roller  5  and the exhaust cam  20  maintain a constant gap therebetween. 
     Thus, the socket module of the compression release type of engine brake according to the exemplary form of the present disclosure and the operation method of the engine brake using the same apply the stopper  90  that limits the position of the brake valve, so that the brake valve can be prevented from coming off the housing  40  with a simple structure. 
     Accordingly, the socket module of the compression release type of engine brake and the operation method can prevent product defects and improve product performance and durability. 
     Thus, the socket module of the compression release type of engine brake according to the exemplary form of the present disclosure and the operation method of the engine brake using the same apply the reset member  100  to automatically exhaust the brake oil introduced into the housing  40  during engine brake operation so that it is possible to prevent the exhaust valve  10  from contacting the engine piston. 
     That is, the oil in the socket module is exhausted every cycle, so that the valve lift can be kept constant when the exhaust valve  10  is opened by the main cam lobe  25 . 
     While this present disclosure has been described in connection with what is presently considered to be practical exemplary forms, it is to be understood that the present disclosure is not limited to the disclosed forms. On the contrary, it is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the present disclosure. 
     
       
         
           
               
             
               
                   
               
               
                 &lt;Description of symbols&gt; 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
            
               
                 1: exhaust rocker arm 
                 3: rocker arm shaft 
               
               
                 5: roller 
                 7: adjusting screw 
               
               
                 10: exhaust valve 
                 11: valve bridge 
               
               
                 20: exhaust cam 
                 21: exhaust camshaft 
               
               
                 23: brake cam lobe 
                 25: main cam lobe 
               
               
                 30: socket module 
                 40: housing 
               
               
                 41: mounting portion 
                 41a: mounting groove 
               
               
                 43: inlet 
                 45: brake piston mounting portion 
               
               
                 47: stopper mounting portion 
                 49: outlet 
               
               
                 49a: first outlet 
                 49b: second outlet 
               
               
                 50: reset member mounting 
               
               
                 portion 
               
               
                 50a: first passage 
               
               
                 50b: second passage 
                 51: slanted surface 
               
               
                 60: cap 
                 70: brake piston 
               
               
                 71: receiving groove 
                 73: upper protrusion 
               
               
                 75: lower protrusion 
                 80: check valve 
               
               
                 81: check spring 
                 90: stopper 
               
               
                 91: head portion 
                 93: body portion 
               
               
                 100: reset member 
                 110: reset valve 
               
               
                 111: flow path groove 
                 120: reset spring 
               
               
                 121: spring pin 
                 130: push pin