Patent Publication Number: US-6666178-B1

Title: Valve deactivation with an electro-hydraulic actuator

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to electrically operated hydraulic actuators which, in response to an electrical control signal cause an electrically operated valve device to control the flow of pressurized hydraulic fluid to a pressure responsive actuator for performing a desired function. Electro-hydraulic actuators are found in widespread usage with a solenoid operated valve employed as the electrically responsive control device for pressurizing piston or diaphragm type pressure responsive actuators. 
     Recent demands for increased fuel economy and reduced emissions from internal combustion engines, particularly for motor vehicle applications, have resulted in the development of systems for selectively deactivating the combustion chamber valves in multi-cylinder engines during operation in order to disable combustion in certain of the combustion chambers. This arrangement has been found to be desirable where relatively large displacement multi-cylinder engines are employed in vehicles requiring substantial engine power during portions of the operating cycle but substantially less power in other portions of the cycle. For example, during the idling portion of the operating cycle it is not required that combustion occur in all cylinders of the engine to maintain engine operation. However, when acceleration or power to maintain speed on a grade is required, it is then desired to engage all combustion chambers for firing. 
     Heretofore, systems for selectively deactivating combustion chamber valves during engine operations have provided for releasable latch mechanisms in the valve gear train of cam operated combustion chamber valves. Such latches, upon release, permit lost motion of the valve gear components which prevents valve movement or “lift” of the combustion chamber poppet valves from their closed position against the valve seats. Early forms of engine valve deactivators employed an electric actuator such as a solenoid for moving a latch holding the pivot fulcrum of each valve; and, thus one electrical actuator was required for each valve to be deactivated. This arrangement proved to be not only relatively costly for high volume motor vehicle engine production but also consumed a prohibitive amount of space or volume and often required enlarged valve gear covers of the engine which created problems in packaging the original in the vehicle engine compartment. Therefore, it was desired to provide a way or means of reducing the number of electrical actuators required for effecting deactivation of selected combustion chamber valves. Furthermore, the amount of electrical power required to operate the number of solenoids required to deactivate the desired number of valves, as for example, up to half of the number of combustion chamber valves in the engine, placed a prohibitive burden upon the engine electrical power source which is typically relatively low voltage in the range of 12 to 14 volts direct current. 
     Thus, it has been desired to provide a way or means of reducing the number of solenoids and the size of the solenoids required for selective combustion chamber valve deactivation and yet provide the speed of actuation for movement of the valve deactivating latch mechanism during the cam dwell or base circle period at the engine speed. 
     It has been proposed to use electro-hydraulic actuators for engine valve deactivation. However, such an arrangement employs a solenoid operated valve for each hydraulic actuator for each valve. This letter arrangement would reduce the power requirements for each solenoid but does not reduce the number of solenoids for each engine valve to be deactivated and thus does not enable engine valve deactivators to be utilized without sufficiently increasing the volume of the engine. 
     BRIEF SUMMARY OF THE INVENTION 
     Broadly, the present invention provides an electro-hydraulic actuator of the type employing a solenoid operated valve for controlling flow of pressurized hydraulic fluid to a pressure responsive actuator. More particularly, the electro-hydraulic actuator of the present invention includes a block having a plurality of bores with moveable pistons therein connected to a common valving chamber to which pressurized hydraulic fluid is valved by a single solenoid operated valve. Each of the pistons is connected respectively externally of its bore to an actuator member adapted for operatively contacting a deactivating member for an engine combustion chamber valve. The electro-hydraulic actuator of the present invention includes a bleed passage above the bores for bleeding air from the system upon the depressurization of the piston bores. The electro-hydraulic actuator of the present invention thus enables a single solenoid operated valve to deactivate a hydraulically powers a plurality of actuators for deactivating a plurality of combustion chamber valve mechanisms. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a top view of the electro-hydraulic actuator of the present invention; 
     FIG. 2 is a front elevation view of the assembly of FIG. 1; 
     FIG. 3 is a right side view of the assembly of FIG. 1; 
     FIG. 4 is a section view taken along section indicating lines  4 — 4  of FIG. 1; 
     FIG. 5 is a section view taken along section indicating lines  5 — 5  of FIG. 1; 
     FIG. 6 is a section view taken along section indicating lines  6 — 6  of FIG. 1; 
     FIG. 7 is a section view taken along section indicating lines  7 — 7  of FIG. 3; 
     FIG. 8 is a section view taken along section indicating lines  8 — 8  of FIG. 3; 
     FIG. 9 is a top view of a portion of the combustion chamber valve gear for an engine showing the invention installed for deactivating the engine valves; 
     FIG. 10 is a front elevation view of the installation of FIG. 9; 
     FIG. 11 is a side elevation view of the installation of FIG. 9; and, 
     FIG. 12 is a view taken along view indicating lines  12 — 12  in FIG.  11 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIGS. 1 through 8, the electro-hydraulic actuator of the present invention is indicated generally at  10  and includes a body  12  having therein a valving chamber  14  which communicates with a valve seat  16  formed about inlet passage  18  which communicates with supply channel  20  which extends through the block  12  and is adapted to have one end thereof plugged as indicated at  22 , with the other end thereof connected to a source (not shown) of pressurized fluid as, for example, engine lubricant from the oil pump circuit pressure galleries. 
     In the presently preferred practice of the invention, the valve seat  16  is formed on an annular valve seat member  24  which is inserted in a bore  26  formed in the valving chamber and which communicates with inlet passage  20 . The valve seat member  24  is sealed in the bore  26  by any suitable expedient, as for example, a resilient seal ring  28 . 
     A solenoid operator indicated generally at  30  has a valving body  32  formed with a valving outlet passage  34  therein which terminates in an annular valve seat  36  formed at the end of the outlet passage  34 . Valving body  32  is sealed in valving chamber  14  by any suitable expedient, as for example, resilient seal ring  38 . Outlet passage  34  communicates with exhaust ports  40  formed in body  32  for exhausting fluid from the valving chamber  14 . 
     A moveable valve member or obturator  42  is disposed in the valving chamber  14  between the inlet valve seat  16  and the outlet valve seat  36  for movement therebetween. Solenoid operator  30  includes an operating rod member  43  indicated in dashed outline in FIGS. 4 and 5 which member is operable upon energization of solenoid operator  30  to effect movement of the valve from inlet valve seat  16  to admit fluid from passage  20  through passage  18  into the valving chamber  14 . Upon de-energization of the solenoid operator  30 , operating rod member  43  moves valve member  42  to the closed position against valve seat  16  and opens valve seat  36  to permit fluid to exhaust through passage  34  and ports  40 . 
     A fluid pressure manifold passage  44  is formed in the valve body  12  in spaced parallel arrangement with the inlet passage  20 . Manifold passage  44  communicates with a plurality of piston bores  46 ,  48 ,  50  (see FIG. 7) each of which has disposed therein a piston denoted respectively  52 ,  54 ,  56  and slidably sealed therein by a seal ring denoted respectively  58 ,  60 ,  62 . Each of the pistons  52 ,  54 ,  56  has extending therefrom a piston rod denoted respectively  64 ,  66 ,  68  which extend outwardly of the respective piston bores; and, the outwardly extending end of each piston rod is slidably guided by a suitable bearing denoted respectively  70 ,  72 ,  74  received in the end of each of the piston bores. 
     Each of the piston rods has connected to the end thereof extending from the piston bore an actuating member in the form of an arm denoted respectively  76 ,  78 ,  80  which arm extends from the body  12 . In the present practice of the invention the arms  76 ,  78 ,  80  are arranged in spaced parallel arrangement as shown in FIG. 2 for implementation with an overhead cam type engine valve gear; however, it will be understood that other arrangements may be used. 
     Each of the piston rods  64 ,  66 ,  68  has disposed thereabout a spring denoted respectively  82 ,  84 ,  86  which bias the pistons respectively inwardly of the piston bores  46 ,  48 ,  50 . 
     In the presently preferred practice of the invention, manifold passage  44  is formed by drilling in the end of the body  12  to a depth intersecting piston bore  50 ; and, the open end of manifold passage  44  is sealed with a plug such as the spherical member  88  precision pressed into the open end of the passage  44 . However, alternatively body  12  may be cast with manifold passage  44 , piston bores  46 ,  48 ,  50 , inlet passage  18  and valving chamber  14  cored therein. 
     In the presently preferred practice of the invention, piston bores  46 ,  50  are aligned in spaced parallel arrangement extending in a common direction; and, piston bore  48  is disposed therebetween and extending parallel with respect thereto in an opposite direction. It will be understood however that the number and arrangement of the piston bores may be varied to accommodate different engine valve and valve gear arrangements. 
     Referring to FIGS. 5,  6  and  8 , a bleed passage is provided in each piston bore respectively as denoted by reference numerals  90 ,  92 ,  94  which connect the piston bore with the inlet passage  20 . The bleed passages  90 ,  92 ,  94  thus permit a small amount of bleed flow to the piston bores  46 ,  48 ,  50  when valve  42  is closed against seat  16 . It will be understood that when inlet seal  16  is closed, outlet seat  36  and passage  34  and exhaust ports  40  are open. Solenoid operated valve  30  thus functions as a shut-off and vent valve with respect to valving chamber  14 . Advantageously, bleed flow to the ports  40  is effective to purge trapped air when the assembly  10  is installed in the valve gear arrangement and orientated as shown in FIG. 9 with ports  40  disposed vertically above the piston bores  46 ,  48 ,  50 . In addition, the location of the exhaust or vent port  40  vertically above the engine cam serves to provide a gravity flow of lubricant for lubricating the cam surface. 
     In operation, it will be understood that upon energization of the solenoid  30  valve  42  is raised from seat  16  and pressurized fluid from the inlet passage  20  flows into the valving passage  14  through the manifold passage  44  and into the piston bores forcing the pistons in an outward direction to move the actuator arms to the position shown in dashed outline in the drawings. This movement of the actuator arms  76 ,  78 ,  80  is employed for valve deactivation in a manner as will hereinafter be described. 
     Referring now to FIGS. 9 through 12, the electro-hydraulic actuator  10  is shown installed in the valve gear of an overhead cam engine having an overhead camshaft  96  with roller followers  98 , 100  each mounted on a rocker arm  102 ,  104  respectively which have an end thereof respectively pivoted on a stationary lash adjuster  108 , 110  with the opposite end thereof pivotally contacting the end of an intake valve  112  and an exhaust valve  114  respectively. Each of the rocker arms  102 , 104  includes a moveable latch member, one of which is illustrated in the foreground and shown in FIG.  11  and denoted reference numeral  106  for the exhaust valve rocker arm  104 . 
     Actuator  10  is mounted on suitable engine structure (not shown) to maintain its position and orientation with respect to the engine valve gear. It will be understood that rocker arm  102  effects actuation of intake valve  112  and rocker arm  104  effects actuation of exhaust valve  114  during normal engine operation and rotation of the camshaft  96 . 
     For normal engine operation, actuator arm  78  of the actuator  10  contacts the end of rocker arm latch member  106  to hold it in the position shown in FIG. 11 with the end of the slot  116  registered against the pin  118  to engage the latch and effect normal movement of the exhaust valve  114 . Upon energization of the solenoid operator  30 , actuator  10  causes arm  78  to move to the position shown in dashed outline thereby permitting latch member  106  to move to the position shown in dashed outline with the opposite end of slot  116  contacting the opposite side of pin  118  and effecting release of the latch mechanism in the rocker arm  104  which causes the rocker arm to provide lost motion and disablement of the movement of the valve  114 . In a similar fashion, actuator arm  80 , which contacts the end of a latch (not shown) but similar to member  106  on rocker arm  102 , is moved to the position shown in dashed outline in FIG. 11 for disablement of movement of the intake valve  112 . It will be understood that actuator arm  76  contacts a third rocker arm latch mechanism (not shown) for disablement of a third combustion chamber valve (not shown). It will be understood that the valve gear arrangement illustrated is for an arrangement wherein the engine has two intake valves and one exhaust valve; and, the second intake valve has been omitted for simplicity of illustration. 
     The present invention thus provides a simple and low cost electro-hydraulic actuator for use in engine valve disablement wherein a single solenoid operated hydraulic actuator can disable plural valves. The arrangement of the present invention thus provides an electro-hydraulic actuator requiring minimum volume for installation in the engine and reduced power consumption for the solenoid operators. 
     Although the invention has hereinabove been described with respect to the illustrated embodiments, it will be understood that the invention is capable of modification and variation and is limited only by the following claims.