Patent Publication Number: US-10316864-B2

Title: Devices for producing vacuum using the venturi effect

Description:
RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 62/146,444, filed Apr. 13, 2015, which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     This application relates to devices for producing vacuum using the Venturi effect, more particularly to such devices having increased suction flow generated with a moderate motive flow rate. 
     BACKGROUND 
     Engines, for example vehicle engines, are being downsized and boosted, which is reducing the available vacuum from the engine. This vacuum has many potential uses, including use by the vehicle brake booster. 
     One solution to this vacuum shortfall is to install a vacuum pump. Vacuum pumps, however, have a significant cost and weight penalty to the engine, their electric power consumption can require additional alternator capacity, and their inefficiency can hinder fuel economy improvement actions. 
     Another solution is an aspirator that generates vacuum by creating an engine air flow path that is parallel to the throttle, referred to as an intake leak. This leak flow passes through a Venturi that generates a suction vacuum. The problem with the presently available aspirators is that they are limited in the amount of vacuum mass flow rate they can generate, and by the amount of engine air they consume. 
     A need exists for improved designs that generate an increased suction mass flow rate, in particular when the motive flow is a boosted motive flow. 
     SUMMARY 
     Devices are disclosed herein that generate increased suction mass flow rate, in particular, when the motive flow is a boosted motive flow, for example, from a turbocharger or supercharger. The devices for producing vacuum using the Venturi effect have a housing defining a suction chamber, a motive passageway converging toward the suction chamber and in fluid communication therewith, a discharge passageway diverging away from the suction chamber and in fluid communication therewith, and a suction passageway in fluid communication with the suction chamber. Within the suction chamber, a motive exit of the motive passageway is generally aligned with and spaced apart from a discharge entrance of the discharge passageway to define a Venturi gap, and the suction passageway enters the suction chamber at a position that generates about a 180 degree change in the direction of suction flow from the suction passageway to the discharge passageway. 
     The motive passageway and the discharge passageway both diverge in cross-sectional area away from the suction chamber as a hyperbolic or parabolic function. The motive exit of the motive passageway has a first corner radius inside the motive passageway, and the discharge entrance is generally flush with a wall of the suction chamber and transitions thereto with a second corner radius. The second corner radius is preferably larger than the first corner radius, and the cross-sectional area of the motive exit is smaller than the cross-sectional area of the discharge entrance. 
     The motive passageway in any of the variations of the devices disclosed herein terminates in a spout protruding into the suction chamber and disposed spaced apart from all one or more sidewalls of the suction chamber, thereby providing suction flow around the entirety of an exterior surface of the spout. The exterior surface of the spout converges toward the outlet end of the motive passageway with one or more converging angles when viewed in a longitudinal cross-section, and the suction chamber has a generally rounded interior bottom below the spout. 
     In all the various embodiments of the devices, the suction chamber has about a 10 mm to about a 25 mm internal width, and has an electromechanical valve in the suction passageway controlling fluid flow into the suction chamber. The electromechanical valve is preferably a solenoid valve in a normally closed position. 
     The devices for producing vacuum using the Venturi effect have a housing defining a suction chamber, a motive passageway converging toward the suction chamber and in fluid communication therewith, a discharge passageway diverging away from the suction chamber and in fluid communication therewith, and a suction passageway in fluid communication with the suction chamber. Within the suction chamber, a motive exit of the motive passageway is generally aligned with and spaced apart from a discharge entrance of the discharge passageway to define a Venturi gap, and the motive passageway terminates in a spout protruding into the suction chamber disposed spaced apart from all one or more sidewalls of the suction chamber thereby providing suction flow around the entirety of an exterior surface of the spout. 
     In all the various embodiments of the devices, the suction passageway is preferably disposed parallel to the discharge passageway, and the exterior surface of the spout converges toward the outlet end of the motive passageway. Also, the motive exit has a first corner radius inside the motive passageway, and the discharge entrance is generally flush with an end wall of the suction chamber and transitions thereto with a second corner radius. The second corner radius is larger than the first corner radius, and the motive passageway and the discharge passageway both diverge in cross-sectional area away from the suction chamber as a hyperbolic or parabolic function. The cross-sectional area of the motive exit is smaller than the cross-sectional area of the discharge entrance, and the suction chamber has a generally rounded interior bottom below the spout. 
     In all the various embodiments of the devices, an electromechanical valve is disposed in the suction passageway to control fluid flow into the suction chamber. The electromechanical valve is preferably a solenoid valve in a normally closed position. 
     Also disclosed herein are systems that include any one of the devices for producing vacuum using the Venturi effect, such as those devices described above and below. Also included in the system is a source of boost pressure fluidly connected to the motive passageway, a device requiring vacuum fluidly connected to the suction passageway, and atmospheric pressure fluidly connected to the discharge passageway. Atmospheric pressure is less than the boost pressure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a side, perspective view of a device that generates vacuum using the Venturi effect. 
         FIG. 1B  is a side, perspective view of just the inlet end of the motive port of an alternate embodiment of the device of  FIG. 1A . 
         FIG. 2  is a side, longitudinal, exploded cross-sectional view of the device of  FIG. 1  taken along line A-A. 
         FIG. 3  is a side, perspective view, generally from the motive exit end, of the motive port portion of the device of  FIG. 1 . 
         FIG. 4A  is an enlarged, side, cross-sectional perspective view of the portion of the device of  FIG. 1  inside the dashed oval. 
         FIG. 4B  is a further enlargement of the outlet end  134  and the inlet end  150  to emphasize the corner radii  162 ,  164 . 
         FIG. 5  is a side, perspective view of a device that generates vacuum using the Venturi effect and includes a solenoid valve. 
         FIG. 6  is a side, longitudinal cross-sectional view of the device of  FIG. 5 . 
         FIG. 7  is an exploded cross-sectional view of the solenoid valve found in the device of  FIG. 6 . 
         FIG. 8  is a top plan view of the solenoid valve found in the device of  FIGS. 5 and 6 . 
         FIG. 9  is a bottom plan view of the solenoid valve found in the device of  FIGS. 5 and 6 . 
         FIG. 10  is a partial, side, longitudinal cross-sectional view of an alternate embodiment of a solenoid valve portion of the device of  FIG. 5 . 
         FIG. 11  is a model of the internal passageway within the motive section. 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description will illustrate the general principles of the invention, examples of which are additionally illustrated in the accompanying drawings. In the drawings, like reference numbers indicate identical or functionally similar elements, even when the first digit is different, for example, reference  100  and reference  200  distinguishing a first embodiment from a second embodiment. 
     As used herein, “fluid” means any liquid, suspension, colloid, gas, plasma, or combinations thereof. 
       FIGS. 1A-4  illustrate different views of a device  100  for producing vacuum using a Venturi effect. The device  100  may be used in an engine, for example, in a vehicle&#39;s engine (an internal combustion engine) to provide vacuum to a device requiring vacuum, such as a vehicle brake boost device, positive crankcase ventilation system, a fuel vapor canister purge device, a hydraulic and/or pneumatic valve, etc. Device  100  includes a housing  106  defining a suction chamber  107  in fluid communication with passageway  104  ( FIG. 2 ), which extends from the motive entrance  132  of the motive port  108  to the discharge exit  156  of the discharge port  112 . The device  100  has at least three ports that are connectable to an engine or components connected to the engine. The ports include: (1) a motive port  108 ; (2) a suction port  110 , which can connect via an optional check valve (not shown) to a device requiring vacuum  180 ; and (3) a discharge port  112 . Each of these ports  108 ,  110 , and  112  may include a connector feature  117  on an outer surface thereof for connecting the respective port to a hose or other component in the engine, as shown in  FIG. 1B  for the motive port  108 . 
     Referring now to  FIGS. 1A and 2 , the housing  106  defining the suction chamber  107  includes a first end wall  120  proximate the motive port  108 , a second end wall  122  proximate the discharge port  112  and at least one side wall  124  extending between the first and second end walls  120 ,  122 . The suction chamber when viewed in a transverse cross-section may be generally pear-shaped, i.e., having a rounded top  148  and rounded bottom  149  where the rounded top is narrower than the rounded bottom. As shown in  FIG. 2 , the suction chamber  107  may be a two-part construction having a container  118   a  and a lid  118   b , where the lid  118   b  seats within or against a rim  119  of the container  118   a  with a fluid-tight seal. Here, the container  118   a  includes the suction port  110  and the discharge port  112  and the lid  118   b  includes the motive port  108 , but is not limited thereto. In another embodiment, the container could include the motive port and the lid could include the suction port and the discharge port. 
     Still referring to  FIG. 2 , the motive port  108  defines a motive passageway  109  converging toward the suction chamber  107  and in fluid communication therewith, the discharge port  112  defines a discharge passageway  113  diverging away from the suction chamber  107  and in fluid communication therewith, and the suction port  110  defines a suction passageway  111  in fluid communication with the suction chamber  107 . These converging and diverging sections gradually, continuously taper along the length of at least a portion of the interior passageway  109 ,  111 , or  113 . The motive port  108  includes an inlet end  130  having a motive entrance  132  and an outlet end  134  having a motive exit  136 . Similarly, the suction port  110  includes an inlet end  140  having a suction entrance  142  and an outlet end  144  having a suction exit  146 , wherein both the motive exit  136  and the suction exit  146  exit into the suction chamber  107 . The discharge port  112  includes an inlet end  150 , proximate the suction chamber  107 , having a discharge entrance  152 , and an outlet end  154 , distal from the suction chamber  107 , having a discharge exit  156 . As illustrated in  FIG. 2 , the suction passageway  111  enters the suction chamber  107  at a position that generates about a 180 degree change in the direction of the suction flow from the suction passageway  111  to the discharge passageway  113 . Accordingly, the suction port  110  is generally parallel to the discharge port  112 . 
     In the assembled device  100 , in particular, within the suction chamber  107 , as shown in  FIG. 4 , the outlet end  134  of the motive passageway  109 , more specifically, the motive exit  136 , is generally aligned with and spaced apart from the discharge entrance  152  at the inlet end  150  of the discharge passageway  113  to define a Venturi gap  160 . The Venturi gap  160 , as used herein, means the lineal distance V D  between the motive exit  136  and the discharge entrance  152 . The motive exit  136  has a first corner radius  162  inside the motive passageway  109 , and the discharge entrance  152  is generally flush with the second end wall  122  of the suction chamber  107  and transitions thereto with a second corner radius  164  that is larger than the first corner radius  162 . These corner radii  162 ,  164  are advantageous because not only does the curvature influence the direction of flow, it also helps to maximize the overall entrance and exit dimensions. 
     Referring to  FIGS. 2-4 , the motive passageway  109  terminates in a spout  170  protruding into the suction chamber  107 , which has an internal width W 1  as labeled in  FIG. 4  of about a 10 mm to about a 25 mm, or more preferably about 15 mm to about 20 mm. The spout  170  is disposed spaced apart from all one or more sidewalls  124  of the suction chamber  107 , thereby providing suction flow around the entirety of an exterior surface  172  of the spout  170 . The exterior surface  172  is generally frustoconical and converges toward the outlet end  134  of the motive passageway  109  with a first converging angle θ 1  (labeled in  FIG. 3 ). The exterior surface  172  may transition into a chamfer  174  more proximate the outlet end  134  than the first end wall  120 . The chamfer  174  has a second converging angle θ 2  that is greater than the first converging angle θ 1 . The chamber  174  as shown in  FIG. 3  changes the generally circular frustoconical exterior surface  172  to a generally more rounded-rectangular or elliptical frustoconical shape. The bottom of the suction chamber  107  below the spout  170  may have a generally rounded interior bottom. The shape of the exterior surface  172 , and/or the chamfer  174 , and the interior bottom of the suction chamber  107  is advantageous to direct suction flow toward the discharge entrance  152  and do so with minimal disturbance/interference in the flow. 
     The spout  170  has a wall thickness T that may be about 0.5 mm to about 5 mm, or about 0.5 to about 3 mm, or about 1.0 mm to about 2.0 mm depending upon the material selected for the construction of the device  100 . 
     Also, as best seen in  FIG. 4 , the cross-sectional area of the motive exit  136  is smaller than the cross-sectional area of the discharge entrance  152 , this difference is referred to as the offset. The offset of the cross-sectional areas may vary depending upon the parameters of the system into which the device  100  is to be incorporated. In one embodiment, the offset may be in the range of about 0.1 mm to about 2.0 mm, or more preferably in a range of about 0.3 mm to about 1.5 mm. In another embodiment, the offset may be in the range of about 0.5 m to about 1.2 mm, or more preferably in a range of about 0.7 to about 1.0 mm. 
     When device  100  is for use in a vehicle engine, the vehicle manufacturer typically selects the size of both the motive port  108  and discharge port  112  based on the tubing/hose size available for connection of the aspirator to the engine or components thereof. Additionally, the vehicle manufacturer typically selects the maximum motive flow rate available for use in the system, which in turn will dictate the area of the interior opening defined at the motive outlet end  134 , i.e., the motive exit  136 . Working within these constraints, the disclosed devices  100  significantly reduce the compromise between the desire to produce high suction flow rates at moderate motive flow rates provided under boost conditions of an engine. This reduction in the compromise is accomplished by changing the configuration of the orientation of the suction port  110 , the suction chamber  107 , including its internal width and shape, the spout of the motive port  108 , the offset of the motive exit and the discharge entrance, adding the corner radii to the motive exit and/or the discharge entrance, and varying the Venturi gap V D . 
     In operation, the device  100 , in particular the suction port  110 , is connected to a device requiring vacuum (see  FIG. 1 ), and the device  100  creates vacuum for said device by the flow of fluid, typically air, through passageway  104 , extending generally the length of the device, and the Venturi gap  160  (labeled in  FIG. 4 ) defined thereby within the suction chamber  107 . In one embodiment, the motive port  108  is connected for fluid communication of its motive passageway with a source of boost pressure and the discharge passageway is connected for fluid communication of its discharge passageway with atmospheric pressure, which is less than the boost pressure. In such an embodiment, the device  100  may be referred to as an “ejector.” In another embodiment, the motive port  108  may be connected to atmospheric pressure and the discharge port may be connected to a source of pressure that is less than atmospheric pressure. In such an embodiment, the device  100  may be referred to as an “aspirator.” The flow of fluid (e.g., air) from the motive port to the discharge port draws the fluid down the motive passageway, which can be a straight cone, a parabolic profile, or a hyperbolic profile, as described herein. The reduction in area causes the velocity of the air to increase. Because this is an enclosed space the laws of fluid mechanics state that the static pressure must decrease when the fluid velocity increases. The minimum cross sectional area of the converging motive passageway abuts the Venturi gap. As air continues to travel to the discharge port, it travels through the discharge entrance and diverging discharge passageway, which is either a straight cone, a parabolic profile, or a hyperbolic profile. Optionally, the discharge passageway can continue as a straight, parabolic profile, or hyperbolic profile cone until it joins the discharge exit, or it can transition to a simple cylindrical or tapered passage before reaching the discharge exit. 
     In a desire to increase the flow rate of air from the suction port  110  into the Venturi gap  160 , the area of the Venturi gap is increased by increasing the perimeter of the discharge entrance  152  without increasing the overall inner dimension of the first motive passageway  109  (preferably with no increase in the mass flow rate). In particular, the motive exit  136  and the discharge entrance  152  are non-circular as explained in co-owned U.S. patent application Ser. No. 14/294,727, filed on Jun. 3, 2014 because a non-circular shaped having the same area as a passageway with a circular cross-section is an increase in the ratio of perimeter to area. There are an infinite number of possible shapes that are not circular, each with a perimeter and a cross sectional area. These include polygons, or straight line segments connected to each other, non-circular curves, and even fractal curves. To minimize cost a curve is simpler and easy to manufacture and inspect, and has a desirable perimeter length. In particular, elliptical- or polygonal-shaped embodiments for the internal cross-sections of the motive and discharge passageways are discussed in the co-owned application referred to above. This increase in perimeter, which is further enhanced by the first corner radius of the motive exit and the second corner radius of the discharge entrance disclosed herein, will again provide the advantage of increasing the intersection area between the Venturi gap and the suction port, resulting in an increase in suction flow. 
     So, as shown in  FIG. 2 , the motive passageway  109  and the discharge passageway  113  both converge in cross-sectional area toward the suction chamber  107  as a hyperbolic or parabolic function. The motive entrance  132  and the discharge exit  156  may be the same shape or different and may be generally rectangular, elliptical or circular. In  FIGS. 1A and 2 , motive entrance  132  and the discharge exit  156  are depicted as circular, but the motive exit  136  and the discharge entrance  152 , i.e., the interior shape of each opening, are rectangularly- or elliptically-shaped. Other polygonal shapes are also possible, and the devices should not be interpreted to be limited to rectangular or elliptical interior shapes. 
     The interior of the motive passageway  109  and/or the discharge passageway may be constructed to have the same general shape. For example, the shape illustrated in  FIG. 11  herein, which is from co-pending application Ser. No. 14/294,727, begins at the motive inlet end  130  as a circular opening having an area A 1  and gradually, continuously transitions, as a hyperbolic function, to an ellipse opening at the motive exit  136  that has an area A 2 , which is smaller than A 1 . The circular opening at the motive inlet end  130  is connected to the ellipse-shaped motive exit  136  by hyperbola lines that provide the advantage of flow lines at the motive exit  136  being parallel to one another. 
     The suction passageway  111  defined by the suction port  110  may be a generally cylindrical passage of constant dimension(s) as shown in  FIG. 1 , or it may gradually, continuously taper as a cone or according to a hyperbolic or parabolic function along its length converging toward the suction chamber  107 . 
     Referring now to  FIGS. 5-9 , a second device for producing vacuum using a Venturi effect, generally designated  200 , is illustrated that has the same or similar features as described above for the embodiment disclosed in  FIGS. 1A-4 . Device  200  differs from device  100  in the inclusion of a solenoid valve  260  to control the flow of fluid through the suction port  210 . Features described above that are repeated in  FIGS. 5-9  have the same numbers other than they begin with a “2,” and as such, an explanation of these features is not duplicated below. 
     The solenoid valve  260  is seated within the suction passageway  211  to control the flow of fluid therethrough. The solenoid valve  260  may be seated in a receptacle  258  defined in the lid  218   b , in the container  218   a , or in a portion of both thereof and includes a spring  259  seated within the chamber  207 , in particular against the interior surface of the second end wall  222 , and connected to a sealing member  266  of the solenoid valve  260 . In  FIG. 6 , the solenoid valve  260  is seated in a receptacle  258  defined in the lid  218   b . The receptacle  258  has a seal seat integral therewith or a seal seat  262  mounted therein to mate a sealing member  266  of the solenoid valve  260  therewith in a fluid-tight engagement. The seal seat  262  defines a bore  274  (see  FIG. 7 ) therethrough in fluid alignment with the suction passageway  211 . The bore  274  is smaller than the bore  278  in a first core  264  of the solenoid valve  260  to seal the suction passageway  211  when the solenoid valve is in a closed position. The seal seat  262  may also include a contoured or beveled face  276  that the sealing member  266  seats against. 
     The solenoid valve  260 , from left to right in  FIG. 7 , includes a first core  264 , the sealing member  266 , a coil  270  wound on a bobbin  268 , and a second core  272 . The first core  264 , the second core  272 , and the sealing member  266  are all made from materials that readily conduct magnetic flux. The first core  264  is generally cup-shaped having a bottom  277  defining a bore  278  therethrough. The bore  278  includes a sealing member-receiving portion  278  having a diameter larger than an outer dimension or outer diameter of the sealing member  266 , such that the sealing member  266  is translatable at least partially therethrough into and out of engagement with the seal seat  262 , and a plurality of flow channels  280  radiating radially outward from the sealing member-receiving portion  278 , which may be best illustrated in  FIG. 8 . The flow channels  280  enable fluid flow around the sealing member  266  and into the chamber  207  defined by the housing  206 . The second core  272  is generally a planar disk mateable to the first core  264  to define a housing for the sealing member  266  and the coil  270  wound on the bobbin  268 . In another embodiment, the first core may be a generally planar disk and the second core may be generally cup-shaped. In another embodiment, the first and second cores may each be generally cup-shaped and mate together to define a housing. In another embodiment, there may be two generally flat cores, one made as  272 , the other made as the bottom of  264 , and a third member being a generally cylindrical part shaped like the axial portion of  264 . 
     The second core  272  defines a bore  295  therethrough. The bore  295  includes a sealing member-seat portion  296  having a diameter similar to the outer dimension of the sealing member  266  and larger than an outer diameter of a spring  259 , and a plurality of flow channels  298  radiating radially outward from the sealing member-seat portion  296 , which may be best illustrated in  FIG. 9 . The sealing member-seat portion  296  may be contoured or beveled to receive a mating portion of the sealing member  266  thereagainst. In one embodiment, the sealing member-seat portion  296  defines a generally conical receptacle. The spring  259  is connected to the sealing member  266  and biases the sealing member  266  into engagement with the seal seat  262  for the closed position. As shown in  FIG. 6 , the sealing member  266  is a solid body with a first end of the spring  259  seated against an end of the sealing member  266 . However, as shown in an alternate embodiment in  FIG. 10 , the sealing member  266 ′ is hollow inside (i.e., defines a hollow core  267 ) and receives the first end of the spring  259  in the hollow core  267 . In both embodiments, the flow channels  298  enable fluid flow around the sealing member  266 ,  266 ′ into the chamber  207  defined by the housing  206 . For maximum fluid flow through the solenoid valve  260 , the flow channels  280  in the first core  264  and the flow channels  298  in the second core  272  are aligned with one another. 
     The bobbin  268  defines a core  271  in which the sealing member  266  is disposed and is translatable. The core  271  may define flow channels  293  between spaced apart guide members  294  defining the core of the bobbin. The guide members  294  are oriented parallel to the longitudinal axis of the sealing member  266  and guide the sealing member  266  as it is translated between the open position and the closed position. Hereto, for maximum fluid flow through the solenoid valve  260 , the flow channels  293  are aligned with the flow channels  280  in the first core  264  and with the flow channels  298  in the second core  272 . The coil  270  wound on the bobbin  268  is connected to electrical connectors (not shown) that are connectable to a source of electric current to activate the solenoid valve  260 . The electrical connectors provide engine designers a plethora of options for control of the suction flow (vacuum) generated by the device  200 . 
     With reference to the sealing member  266  of  FIGS. 6-9 , it has a generally elongate body  289  with a contoured first end  290  and a contoured second end  292 . The elongate body  289  is cylindrical and the first end  290  has a generally conically-shaped exterior surface that seats against the contoured or beveled face  276  of the seal seat  262 . The second end  292  is also a generally conically-shaped exterior surface. The second end  292  seats against the sealing member-seat portion  296  of the second core  272 . In one embodiment, the sealing member  266  may be referred to as a pintle. The sealing member  266  is composed of one or more materials providing it with magnetic properties, so that it can be translated to an open position in response to a magnetic flux created by the first and second cores  264 ,  272 . 
     The solenoid valve  260  of  FIG. 6  is normally closed based on the position of the spring  259 . When an electrical current is applied to the coil  270 , the activated state, a magnetic flux is generated through the first and second cores  264 ,  272 , which moves the sealing member  262  toward and into engagement with the second core  272 , in particular with the sealing member-seat portion  296  thereof, which defines the open position. 
     The addition of the solenoid valve  260  in the device  200  provides the advantage of a simple, inexpensive, compact electrically activated valve to control the suction flow based on selected engine conditions through the use of a controller, such as an automobile&#39;s engine computer. This is advantageous over check valves that open and close merely in reaction to pressure changes in the system. 
     While the solenoid valve  260  as shown in  FIG. 6  is a normally closed valve, it is appreciated that the position of the spring could be changed to make this a normally open valve that is closed in response to an electrical signal from a controller. 
     The devices disclosed herein may be made of a plastic material, except as noted above for component parts of the solenoid valve, or other suitable material(s) for use in a vehicle engine, one that can withstand engine and road conditions, including temperature, moisture, pressures, vibration, and dirt and debris, and may be made by injection molding or other casting or molding processes. 
     Although the invention is shown and described with respect to certain embodiments, it is obvious that modifications will occur to those skilled in the art upon reading and understanding the specification, and the present invention includes all such modifications.