Patent Publication Number: US-9890715-B1

Title: Vacuum for a vacuum consumption device

Description:
FIELD 
     The present description relates generally to devices for providing vacuum to one or more vacuum consumption devices. 
     BACKGROUND/SUMMARY 
     Vehicle systems may include various vacuum consumption devices that are actuated using vacuum. These may include, for example, a brake booster and a purge canister. Vacuum used by these devices may be provided by a dedicated vacuum pump. In other embodiments, one or more aspirators (alternatively referred to as ejectors, venturi pumps, jet pumps, and eductors) may be coupled in the engine system that may harness engine airflow and use it to generate vacuum. 
     In yet another example embodiment shown by Bergbauer et al. in U.S. Pat. No. 8,261,716, a control bore is located in the wall of the intake such that when the throttle plate is at idle position, vacuum generated at the periphery of the throttle is used for a vacuum consumption device. Therein, the positioning of the throttle plate in an idle position provides a constriction at the throttle plate&#39;s periphery. The increasing flow of intake air through the constriction results in a venturi effect that generates a partial vacuum. The control bore is sited so as to utilize the partial vacuum for a vacuum consumption device. 
     The inventors herein have identified potential issues with the above approach. As an example, the vacuum generation potential of the throttle is limited. For example, a single control bore at one location in the intake, as shown in U.S. Pat. No. 8,261,716, is utilized by the vacuum consumption device even though vacuum may be generated at the entire periphery of the throttle. To use vacuum generated at the entire periphery of the throttle, more control bores may be needed in the intake passage. However, fabricating these control bores may result in significant modifications to the design of the intake passage which can increase related expenses. 
     In the approaches that use one or more aspirators to generate vacuum, additional expenses may be incurred because of individual parts that form the aspirator including nozzles, mixing and diffusion sections, and check valves. Further, at idle or low load conditions, it may be difficult to control the total air flow rate into the intake manifold since the flow rate is a combination of leakage flow from the throttle and airflow from the aspirator. Typically, an aspirator shut off valve (ASOV) may be included along with the aspirator to control airflow but with added cost. Further, installing aspirators in the intake can lead to constraints on space availability as well as packaging issues. 
     In one example, the issues described above may be addressed by a method for replenishing vacuum in a vacuum consumption device by flowing air through an annular venturi passage located between identically shaped upper and lower halves of a vacuum generating device. In this way, the vacuum generating device provides vacuum without electronic valves and/or actuators. As one example, air flows through one or more venturi passages of the vacuum generating device. Vacuum is supplied from a venturi passage, through a passage located in the upper half, to the vacuum consumption device. In one example, the vacuum generating device is located in an intake passage and the upper half is configured to slide to and away from the lower half. A position of the upper half is based on an engine operating condition. As an example, the upper half is spaced away from the lower half for higher engine loads and pressed against the lower half for lower/idle engine loads. Thus, the vacuum generating device may adjust intake air flow to an engine while simultaneously providing vacuum to the vacuum consumption device. 
     It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  portrays a schematic diagram of an engine in accordance with the present disclosure. 
         FIG. 2  depicts a first embodiment of a vacuum generating device. 
         FIG. 3  depicts a first position of the vacuum generating device. 
         FIG. 4  depicts a second position of the vacuum generating device. 
         FIG. 5  depicts a second embodiment of a vacuum generating device. 
         FIG. 6  depicts a cross-section of the second embodiment. 
         FIGS. 2-6  are shown approximately to scale. 
         FIG. 7  depicts a system comprising the first embodiment and the second embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     The following description relates to systems and methods for replenishing vacuum in a vacuum consumption device. The vacuum consumption device may be used in an engine system, where it is coupled to a first vacuum generating device in an intake passage and/or to a second vacuum generating device in an auxiliary passage, as shown in  FIG. 1 . The first vacuum generating device comprises upper and lower halves having substantially identical outer surfaces. The halves are hollow and configured to supply vacuum from an annular venturi passage to the vacuum consumption device, as shown in  FIG. 2 . A motive air flow, suck flow, and vacuum flow through the first vacuum generating device in a first position is shown in  FIG. 3 . A motive air flow, suck flow, and vacuum flow through the first vacuum generating device in a second position is shown in  FIG. 4 . The second vacuum generating device comprises upper and lower halves substantially identical to the halves of the first vacuum generating device. The second vacuum generating device also comprises an annular venturi passage, however, the second vacuum generating device differs from the first in that it is completely fixed, while the first vacuum generating device comprises slidable components. The second vacuum generating device is shown in  FIG. 5 . A motive air flow, suck flow, and vacuum flow through the second vacuum generating device is shown in  FIG. 6 . Lastly, a system comprising both the first and second vacuum generating devices is shown in  FIG. 7 . 
       FIGS. 1-7  show example configurations with relative positioning of the various components. If shown directly contacting each other, or directly coupled, then such elements may be referred to as directly contacting or directly coupled, respectively, at least in one example. Similarly, elements shown contiguous or adjacent to one another may be contiguous or adjacent to each other, respectively, at least in one example. As an example, components laying in face-sharing contact with each other may be referred to as in face-sharing contact. As another example, elements positioned apart from each other with only a space there-between and no other components may be referred to as such, in at least one example. As yet another example, elements shown above/below one another, at opposite sides to one another, or to the left/right of one another may be referred to as such, relative to one another. Further, as shown in the figures, a topmost element or point of element may be referred to as a “top” of the component and a bottommost element or point of the element may be referred to as a “bottom” of the component, in at least one example. As used herein, top/bottom, upper/lower, above/below, may be relative to a vertical axis of the figures and used to describe positioning of elements of the figures relative to one another. As such, elements shown above other elements are positioned vertically above the other elements, in one example. As yet another example, shapes of the elements depicted within the figures may be referred to as having those shapes (e.g., such as being circular, straight, planar, curved, rounded, chamfered, angled, or the like). Further, elements shown intersecting one another may be referred to as intersecting elements or intersecting one another, in at least one example. Further still, an element shown within another element or shown outside of another element may be referred as such, in one example. It will be appreciated that one or more components referred to as being “substantially similar and/or identical” differ from one another according to manufacturing tolerances (e.g., within 1-5% deviation). Additionally, upstream and downstream are in relation to a direction of gas flow unless otherwise specified. 
     Referring now to  FIG. 1 , it shows a schematic depiction of a spark ignition internal combustion engine  10 . Engine  10  may be controlled at least partially by a control system including controller  12  and by input from a vehicle operator  132  via an input device  130 . In this example, input device  130  includes an accelerator pedal and a pedal position sensor  134  for generating a proportional pedal position signal PP. 
     Combustion chamber  30  (also known as, cylinder  30 ) of engine  10  may include combustion chamber walls  32  with piston  36  positioned therein. Piston  36  may be coupled to crankshaft  40  so that reciprocating motion of the piston is translated into rotational motion of the crankshaft. Crankshaft  40  may be coupled to at least one drive wheel of a vehicle via an intermediate transmission system (not shown). Further, a starter motor may be coupled to crankshaft  40  via a flywheel (not shown) to enable a starting operation of engine  10 . 
     Combustion chamber  30  may receive intake air from intake manifold  44  via intake passage  42  and may exhaust combustion gases via exhaust passage  48 . Intake manifold  44  and exhaust passage  48  can selectively communicate with combustion chamber  30  via respective intake valve  52  and exhaust valve  54 . In some embodiments, combustion chamber  30  may include two or more intake valves and/or two or more exhaust valves. 
     In this example, intake valve  52  and exhaust valves  54  may be controlled by cam actuation via respective cam actuation systems  51  and  53 . Cam actuation systems  51  and  53  may each include one or more cams and may utilize one or more of cam profile switching (CPS), variable cam timing (VCT), variable valve timing (VVT) and/or variable valve lift (VVL) systems that may be operated by controller  12  to vary valve operation. The position of intake valve  52  and exhaust valve  54  may be determined by position sensors  55  and  57 , respectively. In alternative embodiments, intake valve  52  and/or exhaust valve  54  may be controlled by electric valve actuation. For example, cylinder  30  may alternatively include an intake valve controlled via electric valve actuation and an exhaust valve controlled via cam actuation including CPS and/or VCT systems. 
     Fuel injector  66  is shown coupled directly to combustion chamber  30  for injecting fuel directly therein in proportion to the pulse width of signal FPW received from controller  12  via electronic driver  96 . In this manner, fuel injector  66  provides what is known as direct injection of fuel into combustion chamber  30 . The fuel injector may be mounted in the side of the combustion chamber or in the top of the combustion chamber, for example. Fuel may be delivered to fuel injector  66  by a fuel system (not shown) including a fuel tank, a fuel pump, and a fuel rail. In some embodiments, combustion chamber  30  may alternatively or additionally include a fuel injector arranged in intake manifold  44  in a configuration that provides what is known as port injection of fuel into the intake port upstream of combustion chamber  30 . 
     Ignition system  88  can provide an ignition spark to combustion chamber  30  via spark plug  92  in response to spark advance signal SA from controller  12 , under select operating modes. Though spark ignition components are shown, in some embodiments, combustion chamber  30  or one or more other combustion chambers of engine  10  may be operated in a compression ignition mode, with or without an ignition spark. 
     Engine  10  may further include a compression device such as a turbocharger or supercharger including at least a compressor  162  arranged along intake passage  42 . For a turbocharger, compressor  162  may be at least partially driven by a turbine  164  (e.g., via a shaft) arranged along exhaust passage  48 . Compressor  162  draws air from intake passage  42  to supply boost chamber  46 . Exhaust gases spin turbine  164  which is coupled to compressor  162  via shaft  161 . For a supercharger, compressor  162  may be at least partially driven by the engine and/or an electric machine, and may not include a turbine. Thus, the amount of compression provided to one or more cylinders of the engine via a turbocharger or supercharger may be varied by controller  12 . 
     A wastegate  168  may be coupled across turbine  164  in a turbocharger. Specifically, wastegate  168  may be included in a bypass  166  coupled between an inlet and outlet of the exhaust turbine  164 . By adjusting a position of wastegate  168 , an amount of boost provided by the turbine may be controlled. 
     Intake manifold  44  is shown communicating with throttle  62  having a throttle plate  64 . In this particular example, the position of throttle plate  64  may be varied by controller  12  via a signal provided to an electric motor or actuator (not shown in  FIG. 1 ) included with throttle  62 , a configuration that is commonly referred to as electronic throttle control (ETC). Throttle position may be varied by the electric motor via a shaft. As elaborated in  FIGS. 2-4 , throttle plate  64  may be at least partially hollow and may include an opening  68  which fluidically couples the throttle with vacuum consumption device  140 . Throttle  62  may control airflow from intake boost chamber  46  to intake manifold  44  and combustion chamber  30  among other engine cylinders. The position of throttle plate  64  may be provided to controller  12  by throttle position signal TP from throttle position sensor  58 . 
     Engine  10  is coupled to vacuum consumption device  140  which may include, as non-limiting examples, one of a brake booster, a fuel vapor canister, and a vacuum-actuated valve (such as a vacuum-actuated wastegate and/or EGR valve). Vacuum consumption device  140  may receive vacuum from a plurality of vacuum sources. One source may be vacuum pump  77  that may be selectively operated via a control signal from controller  12  to supply vacuum to vacuum consumption device  140 . Check valve  69  allows air to flow to vacuum pump  77  from vacuum consumption device  140  and limits airflow to vacuum consumption device  140  from vacuum pump  77 . As an example, the check valve  69  allows air to flow to the vacuum pump  77  from the vacuum consumption device  140  in response to a pressure of the vacuum pump  77  being less than a pressure of the vacuum consumption device  140 . In some examples, additionally or alternatively, the vacuum pump  77  may be located in an auxiliary passage outside of the intake passage  42 . As air flows through the auxiliary passage, the vacuum pump  77  may supply vacuum to the vacuum consumption device  140 , as will be described in greater detail below. 
     Another source of vacuum may be throttle plate  64  which is positioned within boost chamber  46 . As shown in  FIG. 1 , an opening  68  within throttle plate  64  may be connected to vacuum consumption device  140  via a hollow shaft mounted on bearings (not shown) and coupled to a conduit  198 . A position of the throttle plate  64  may be adjusted based on a manifold pressure, in some examples. Check valve  73  ensures that air flows from vacuum consumption device  140  to throttle plate  64  and thereon into intake manifold  44  and not from intake manifold  44  to vacuum consumption device  140 . In one example, the throttle  62  and the vacuum pump  77  are substantially identical devices. 
     Exhaust gas sensor  126  is shown coupled to exhaust passage  48  upstream of emission control device  70 . Sensor  126  may be any suitable sensor for providing an indication of exhaust gas air/fuel ratio such as a linear oxygen sensor or UEGO (universal or wide-range exhaust gas oxygen), a two-state oxygen sensor or EGO, a HEGO (heated EGO), a NOx, HC, or CO sensor. Emission control device  70  is shown arranged along exhaust passage  48  downstream of exhaust gas sensor  126 . Device  70  may be a three way catalyst (TWC), NOx trap, various other emission control devices, or combinations thereof. 
     An exhaust gas recirculation (EGR) system may be used to route a desired portion of exhaust gas from exhaust passage  48  to intake manifold  44  through conduit  152  via EGR valve  158 . Alternatively, a portion of combustion gases may be retained in the combustion chambers, as internal EGR, by controlling the timing of exhaust and intake valves. 
     Controller  12  is shown in  FIG. 1  as a conventional microcomputer including: microprocessor unit  102 , input/output ports  104 , read-only memory  106 , random access memory  108 , keep alive memory  110 , and a conventional data bus. Controller  12  commands various actuators such as throttle plate  64 , EGR valve  158 , and the like. Controller  12  is shown receiving various signals from sensors coupled to engine  10 , in addition to those signals previously discussed, including: engine coolant temperature (ECT) from temperature sensor  112  coupled to cooling sleeve  114 ; a position sensor  134  coupled to an accelerator pedal  130  for sensing accelerator position adjusted by vehicle operator  132 ; a measurement of engine manifold pressure (MAP) from pressure sensor  121  coupled to intake manifold  44 ; a measurement of boost pressure from pressure sensor  122  coupled to boost chamber  46 ; a measurement of vacuum in vacuum consumption device  140  from pressure sensor  125 , a profile ignition pickup signal (PIP) from Hall effect sensor  118  (or other type) coupled to crankshaft  40 ; a measurement of air mass entering the engine from mass airflow sensor  120 ; and a measurement of throttle position from sensor  58 . Barometric pressure may also be sensed (sensor not shown) for processing by controller  12 . In a preferred aspect of the present description, engine position sensor  118  produces a predetermined number of equally spaced pulses every revolution of the crankshaft from which engine speed (RPM) can be determined. 
     The controller  12  receives signals from the various sensors of  FIG. 1  and employs the various actuators of  FIG. 1  to adjust engine operation based on the received signals and instructions stored on a memory of the controller. For example, adjusting the throttle plate may include adjusting an actuator of the throttle plate to adjust a position of the throttle plate. As an example, the actuator may be signaled to move the throttle plate to a more open position in response to a tip-in (e.g., accelerator pedal  130  in a more depressed position). 
     As described above,  FIG. 1  merely shows one cylinder of a multi-cylinder engine, and that each cylinder has its own set of intake/exhaust valves, fuel injectors, spark plugs, etc. Also, in the example embodiments described herein, the engine may be coupled to a starter motor (not shown) for starting the engine. The starter motor may be powered when the driver turns a key in the ignition switch on the steering column, for example. The starter is disengaged after engine start, for example, by engine  10  reaching a predetermined speed after a predetermined time. Turning now to  FIG. 2 , it shows an isometric view  200  of a vacuum generating device  210 . 
     Portions of the vacuum generating device  210  shown in dashed lines are occluded by portions of the vacuum generating device  210  shown in solid lines. In one example, the vacuum generating device  210  may be used as the throttle  62  of  FIG. 1 . Additionally or alternatively, the vacuum generating device  210  may be used as the vacuum pump  77  of  FIG. 1 . As such, the vacuum generating device  210  may be adapted to be located in the intake passage  42  or in an auxiliary passage fluidly coupling the vacuum generating device  210  to an ambient atmosphere. 
     An axis system  290  is shown comprising three axes namely, an x-axis parallel to the horizontal direction, a y-axis parallel to the vertical direction, and a z-axis perpendicular to the x- and y-axes. A direction of gravity is shown by arrow  299 , which is parallel to the y-axis. A vertical axis  295  is shown extending through a geometric center of the vacuum generating device  210  parallel to the y-axis. 
     The vacuum generating device  210  may be partially hollow and configured to admit air therethrough to provide vacuum to a vacuum consumption device. The vacuum generating device  210  may flow the air to an intake manifold of an engine (e.g., similar to throttle  62  of  FIG. 1 ), in some examples. Alternatively, the vacuum generating device  210  may flow the air to an ambient atmosphere, in other examples. As such, a vehicle may comprise two of the vacuum generating device  210 , with one located in an intake passage and the second located outside the intake passage (e.g., in the auxiliary passage) functioning as an auxiliary vacuum generating device. 
     The vacuum generating device  210  comprises upper  220  and lower  230  halves aligned with one another along the vertical axis  295 . Upper body  222  and upper outer surface  224  of the upper half  220  are substantially identical to the lower body  232  and lower outer surface  234  of the lower half  230 , respectively. In one example, the upper  222  and lower  232  bodies are cylindrical and partially hollow for flowing air therethrough. Furthermore, the upper outer surface  224  and lower outer surface  234  are convex and protrude into a space between the halves, forming an annular venturi passage  250  located therebetween, as will be described below. The upper outer surface  224  and lower outer surface  234  protrude toward one another. The upper  224  and lower  226  outer surfaces are toroidal, in one example. In other examples, the upper  224  and lower  226  outer surfaces may be frustconical or other similar geometries. 
     Specifically, the lower half  230  comprises a lower outer surface  234  and a lower inner surface  236  angled oppositely toward one another. The lower outer  234  and lower inner  236  surfaces meet at a lower apex  238 . The upper half  220  also comprises the upper outer surface  224  being oppositely angled to an upper inner surface with an upper apex  228  located at an intersection of the two. A distance between the upper half  220  and the lower half  230  is smallest between the upper apex  228  and the lower apex  238 . During some conditions, the upper  228  and lower  238  apices may be pressed against each other, sealing a venturi passage  250 . The venturi passage  250  is annular and located between the upper  220  and lower  230  halves. As such, the upper outer surface  224  and the lower outer surface  234  correspond to a venturi inlet  252  of the venturi passage  250 . The upper inner surface and lower inner surface  236  correspond to a venturi outlet  254 . Lastly, the upper apex  228  and the lower apex  238  corresponds to a venturi throat  256 . Each of the venturi inlet  252 , venturi outlet  254  and venturi throat  256  are annular, with the outlet  254  located adjacent to the vertical axis  295  and the inlet  252  being spaced farthest away from the vertical axis  295 . 
     The vacuum generating device  210  is located in a pipe  202 . Two embodiments of the pipe  202  are shown. A first embodiment  203  is shown in solid line and is concentric with the upper  220  and lower  230  halves about the vertical axis  295 . The first embodiment  203  traverses in a direction parallel to the vertical axis  295 . A diameter of the first embodiment  203  is greater than diameters of the upper  220  and lower  230  halves up to a junction where the first embodiment  203  is physically coupled to the lower body  232  of the lower half  230 . The upper half  220  may comprise one or more supports and/or connectors slidingly coupled to the first embodiment  203 . Additionally or alternatively, a coupling element may couple the upper  220  and lower  230  halves. 
     A second embodiment  205  of the pipe  202  is shown in dashed line and is perpendicular to the vertical axis  295 . The second embodiment  205  is annular and increases in diameter adjacent to the vacuum generating device  210 . The second embodiment  205  is coupled to the upper  220  and lower  230  halves. The coupling may be via bosses and or other suitable coupling elements capable of allowing one or more of the upper  220  and lower  230  halves to actuate (e.g., slide) parallel to the vertical axis  295 . The coupling between the vacuum generating device  210  and the pipe  202  is described in greater detail below. 
     The pipe  202  is configured to admit air from the ambient atmosphere via passage  204 . In one example, the passage  204  is similar to intake passage  44  of  FIG. 1 . Thus, the air is intake air and is directed to engine  10  of  FIG. 1 . Alternatively, the passage  204  is an auxiliary passage separated from the intake passage  44  of  FIG. 1 . As such, ambient air may flow into the passage  204  from the ambient atmosphere without flowing to the engine  10  and/or intake passage  44 . Therefore, air enters the passage  204  from the ambient atmosphere, flows through the vacuum generating device  210 , and exits the passage  204  to the ambient atmosphere when the passage  204  is an auxiliary passage. A portion of the passage  204  upstream of and adjacent to the vacuum generating device  210  is located in the pipe  202 . A remaining portion of the passage  204  downstream of the vacuum generating device  210  is located in an outlet conduit  208  physically coupled to the lower half  230 . 
     In some examples, additionally or alternatively, a plurality of vacuum generating devices  210  may be utilized on a vehicle, with one located in an intake passage (e.g., intake passage  42  of  FIG. 1 ) and a second located in an auxiliary passage separated from the intake passage. Gas flows from the intake and auxiliary passages may merge in the intake manifold  44  in one example. In other examples, the auxiliary passage may expel gas to an ambient atmosphere without mixing with gas from the intake passage. 
     As described above, the upper  220  and lower  230  halves are partially hollow. Specifically, the upper half  220  comprises interior passages  240  including a first passage  242  and a second passage  244 . The first passage  242  is located along the vertical axis  295  and is cylindrically shaped. The second passage  244  is radially spaced from the vertical axis  295  and is ring shaped with the first passage  242  extending therethrough. The first  242  and second  244  passages are fluidly connected to one another at a trifurcated passage  246 , which comprises two outer passages leading to the second passage  244  and a central passage leading to the first passage  242 . A conduit  280  fluidly couples the upper half  220  and the trifurcated passage  246  to the vacuum consumption device (e.g., vacuum consumption device  140  of  FIG. 1 ). Specifically, the conduit  280  directs suck flow from the vacuum consumption device to the trifurcated passage  246  while simultaneously flowing vacuum to the vacuum consumption device, as will be described below. 
     A check valve  248  in the first passage  242  may dictate a direction of flow of suck flow and vacuum flow through the upper half  220 . In one example, the check valve  248  may actuate to an open position in response to a vacuum exceeding a threshold vacuum, as will be described below. Alternatively, the check valve  248  may actuate to a closed position in response to a vacuum of the venturi passage  250  being less than the threshold vacuum. When the check valve  248  is in the open position, more suck flow may flow from the vacuum consumption device to the first passage  242 . Thus, when the check valve  248  is in the closed position, more suck flow may flow from the vacuum consumption device to the second passage  244 . Gas in the first passage  242  exits the upper half  220  along the vertical axis  295 , radially interior to the upper inner surface. The first passage  242  comprises an outlet  243  facing the lower half  230 . Gas in the second passage  244  exits the upper half  220  via the upper apex  228 . As such, vacuum from the venturi passage  250  enters the upper half  220  through the upper apex  228  via the second passage  244 . 
     The lower half  230  comprises an interior passage  239  located radially interior to the lower inner surface  237 . The interior passage  239  is aligned with the first passage  242  along the vertical axis  295 . Thus, an inlet  272  of the interior passage  239  is located directly opposite the outlet  243  such that the inlet  272  and outlet  243  face one another. In one example, a diameter of the interior passage  239  is greater than a diameter of the first passage  242 . This allows the interior passage  239  to direct air flow from the passage  204  and first passage  242  to the outlet conduit  208 . 
     Thus, during a condition where the check valve  248  is in a closed position, gas may flow through the pipe  202  and around the venturi passage  250  before flowing into the venturi inlet  252 . The gas flows annularly through the venturi inlet  252 , before flowing radially inward passed the venturi throat  256 , and into the venturi outlet  254 , where the gas is directed to the interior passage  239 . As the gas flows by the venturi throat  256  (between the upper  228  and lower  238  apices), vacuum is generated and supplied through the second passage  244  to the vacuum consumption device. As vacuum in the vacuum consumption device is replenished, air flows out of the vacuum consumption device, into the second passage  244 , and into the venturi passage  250 . Air flow during the closed check valve position is described in greater detail in  FIG. 3 . 
     Furthermore, during a condition where the check valve  248  is in an open position, gas flowing through the pipe  202  does not enter the venturi passage  250  due to upper  228  and lower  238  apices being pressed against one another. Vacuum from the intake manifold draws air out of the vacuum consumption device through the first passage  242  and replenishes vacuum in the vacuum consumption device. The air flows through the first passage  242 , through the interior passage  239 , and into the intake manifold  44 . Air flow during the open check valve position is described in greater detail in  FIG. 4 . 
     Turning now to  FIG. 3 , it shows cross-sectional view  300  taken along cutting plane M-M′ shown in  FIG. 2 . As such, components previously presented are similarly numbered and not reintroduced. The vacuum generating device  210  is shown fluidly coupled to the vacuum consumption device  140  and intake manifold  44 . Thus, the passage  204  is substantially identical to intake passage  42  or boost chamber  46  of  FIG. 1 . In this way, the vacuum generating device  210  may be used similarly to throttle  64  of  FIG. 1 . 
     The check valve  248  is in the fully closed position, thereby preventing air from flowing through the first passage  242 . This may occur in response to a vacuum in the first passage  242  being less than a threshold vacuum, where the threshold vacuum is based on an amount of vacuum capable of opening the check valve  248 . In one example, if an engine load is greater than a low engine load and/or idle engine load, then an intake manifold vacuum may be less than the threshold vacuum. However, during higher engine loads above the low and/or idle engine loads, a sufficient mass air flow may flow through the venturi passage  250 . As a result, vacuum is generated at the venturi throat  256  and supplied to the vacuum consumption device  140  through the second passage  244 . 
     The vacuum generating device  210  is shown comprising upper  320  and lower  330  connectors rigidly coupled to the upper  220  and lower  230  halves, respectively. The upper  320  and lower  330  connectors comprise upper  322  and lower  332  locking elements, respectively, for preventing the upper  220  and lower  230  halves from sliding apart from one another. As shown, the upper  322  and lower  332  locking elements are hooked shaped and are oriented oppositely one another. In one example, the upper locking element  322  points in a direction opposite gravity  299  whereas the lower locking element  332  points in a direction parallel to gravity  299 . To prevent misalignment and/or separation of the upper  220  and lower  230  halves, tips  324  and  334  of the upper  322  and lower  332  locking elements, respectively, do not become dislodged. Said another way, tip  334  is more proximal to the upper half  220  than tip  324  throughout a range of motion of the upper  220  and lower  230  halves. 
     The connectors  320  and  330  may set a maximum distance between the upper  220  and lower  230  halves. This may be achieved by having the upper  320  and lower  330  connectors press against one another when the maximum distance between the upper  220  and lower  230  halves is reached. In one example, the tips  324  and  334  press against the lower  332  and upper  322  locking elements, respectively. Thus, for distances between the upper  220  and lower  230  halves less than the maximum distance, the connectors  320  and  330  may not be touching one another. 
     A spring  310  is located between the upper  220  and lower  230  halves. The spring  310  is physically coupled to upper inner surfaces  226  and lower inner surfaces  236  at upper  312  and lower  314  ends, respectively. The spring  310  fully expands when the upper half  220  is the maximum distance away from the lower half  230 . Thus, the spring  310  is fully contracted when the upper half  220  is pressed against the lower half  230 , as shown in  FIG. 4 . In this way, the maximum distance may also be set by the spring  310 . Unwanted noises during the collision between the upper  220  and lower  230  halves may be prevented via the spring  310 . As a result, the spring  310  may slowly contract, thereby reducing an impact force between the upper  220  and lower  230  halves. 
     As described above, the lower half  230  is physically coupled to the pipe  202  in both the first  203  and second  205  embodiments. The upper half  220  may be coupled to the pipe  202  via bores  340  and  342  configured to allow the upper half  220  and upper connector  320  slide in the direction parallel to gravity  299 , up and down the vertical axis  295 . In this way, movement of the upper  220  and lower  230  halves is substantially prevented and only vertical movement of the upper half  220  occurs, in one example. Thus, the lower half  230  is rigidly fixed to the pipe  202 . 
     In the embodiment of  FIG. 3 , the upper half  220  is spaced away from the lower half  230 . Specifically, the upper half  220  is a maximum distance away from the lower half  230 , as indicated by the upper  322  and lower  332  locking elements being pressed against each other. In one example, the upper half  220  slides away from the lower half  230  as an intake manifold pressure increases above a threshold lower manifold pressure. When the upper half  220  is the maximum distance away from the lower half  230 , the intake manifold pressure is equal to a threshold upper manifold pressure. Thus, the intake manifold pressure may be pushing the upper half  220  away. The threshold lower manifold pressure may be based on a pressure of the manifold during idle and/or low engine loads. The threshold upper manifold pressure may be based on a pressure of the manifold during high engine loads. As such, the upper half  220  may be gradually pushed away from the lower half  230  as the manifold pressure increases from the threshold lower manifold pressure to the threshold upper manifold pressure. 
     In some examples, additionally or alternatively, the upper half  220  may be actuated by a motor  380  based on engine operating parameters. For example, a controller (e.g., controller  12  of  FIG. 1 ) may signal to the motor  380  to actuate the upper half  220  farther away from the lower half  230  if an intake air demand of the engine is not being met. In this way, the vacuum generating device  210  may be actuated based on an engine air demand whether it is used as a throttle or as an auxiliary vacuum device. 
     Ambient air  350  flows through the pipe  202  toward the vacuum generating device  210 . The ambient air may be admitted to pipe  202  from an ambient atmosphere via a grill and/or fan. 
     Suck flow  352  flows from the vacuum consumption device  140  to the vacuum generating device  210 . The suck flow is drawn from a vacuum reservoir of the vacuum consumption device  140  as its vacuum is replenished. Vacuum  354  is generated in the venturi passage  250 , where the vacuum  354  flows through the second passage  244  to the vacuum consumption device  140 . 
     Ambient air  350  flows annularly around the vacuum generating device  210  before flowing radially inward into the venturi passage  250  via the venturi inlet  252 . As described above, the venturi passage  250  is annular, spanning an entire distance of the space between the upper  220  and lower  230  halves. The ambient air  350  flows through the venturi throat  256  before entering the venturi outlet  254 . As the ambient air  350  flows through the venturi throat  256 , vacuum is generated adjacent to the upper  228  and lower  238  apices. As such, the vacuum  354  flows into the second passage  244  and is supplied to the vacuum consumption device  140  via the conduit  280 . In return, suck flow  352  flows out of the vacuum consumption device  140 , through the second passage  244 , and delivered to the venturi passage  250  via an annular opening  358  of the upper apex  228 . Suck flow  352  and vacuum  354  do not flow to the first passage  342  when the check valve  348  is in the closed position, in one example. The ambient air  350  and suck flow  352  may merge in the venturi outlet  254  before flowing through the interior passage  239  to the intake manifold  44 . An outlet pipe  360  expels the mixture of ambient air  350  and suck flow  352  from the interior passage  239  to the intake manifold  44 . The outlet pipe  360  is concentric with the outlet conduit  208  about the vertical axis  295 . Additionally, the outlet pipe  360  is smaller in diameter than the outlet conduit  208 . In some examples, the outlet pipe  360  may be omitted. 
     In one example, the embodiment of  FIG. 3  may occur during a high engine load with a vehicle driving on a road. Intake manifold vacuum is low compared to lower engine loads and in response, the check valve remains in the closed position. Additionally, a force of the spring is greater than the manifold vacuum, urging the upper half away from the lower half. The connectors set a maximum distance between the upper and lower halves. The venturi passage opens between the upper and lower halves, where ambient air flows therethrough. Vacuum from the venturi passage flows in to a second passage located wholly inside the upper half. Suck flow exits a vacuum reservoir of a vacuum consumption device as vacuum in the reservoir is replenished. In this way, suck flow mixes with ambient air in the venturi passage when the halves are spaced away from each other. 
     Turning now to  FIG. 4 , it shows cross-sectional view  400 , which is substantially identical to the cross-sectional view  300 , expect that the upper half  220  is pressed against the lower half  230 . Specifically, the upper apex  228  is pressed against the lower apex  238  and as a result, the second passage  244  and venturi passage  250  are sealed. A pressure of the intake manifold may be less than the threshold lower pressure. As such, a vacuum of the intake manifold is high enough to move the check valve  248  toward the open position. Additionally, the spring  310  is moved to a fully compressed position as the manifold vacuum exceeds the force of the spring  310 . As such, ambient flow  450  cannot flow through the venturi throat  256  due to upper  228  and lower  238  apices being pressed against one another. Vacuum  454  flows from the intake manifold  44  to the vacuum consumption device  140  through the open check valve  248  in the first passage  242 . Suck flow  452  flows through the first passage  242  along the vertical axis  295 , through the check valve  248 , through the venturi passage  250 , through the interior passage  239 , through the outlet pipe  360 , and into the outlet conduit  208  toward the intake manifold  44 . As such, during engine operating conditions where intake manifold pressure is low (e.g., low engine loads and/or idle), only suck flow flows through the vacuum generating device  210  to the intake manifold  44 . 
     In one example, the check valve is closed when a vehicle is stopped and in idle. Vacuum from the manifold overcomes the force of the spring and moves the upper half closer to the lower half. The spring slowly contracts to decrease an impact force between the upper and lower halves, thereby mitigating noises generated therefrom. The second passage is sealed from the venturi passage and the intake manifold. Additionally, the venturi passage is sealed from an ambient air passage. Vacuum flows from the manifold through the venturi passage, through the first passage, and to the vacuum consumption device. Suck flow flows exactly opposite to vacuum and is the only source of intake air provided to the intake manifold in one example. In another example, the vacuum generating device is in an auxiliary passage such that the intake manifold may receive ambient air from the vacuum generating device and a throttle. 
     Thus,  FIGS. 3 and 4  show two extreme positions of the vacuum generating device, including a first position where the upper half is farthest away from the lower half and a second position where the upper half is pressed against the lower half. When in the first position, the check valve is closed and ambient air flowing through the venturi passage promotes the flow of suck flow from the vacuum consumption device to the venturi passage via the second passage in the upper half. The motive air and suck flow combine and flow through the interior passage of the lower half before flowing to the intake manifold. When in the second position, the check valve is open and intake manifold vacuum promotes suck flow to flow through the first passage, through the interior passage, and into the intake manifold. 
     In some embodiments, additionally or alternatively, the vacuum generating device may comprise a third position between the first and second positions. As such, suck flow may flow through both the first and second passages when the vacuum generating device is in the third position. In this way, the check valve is at least partially open and the upper half is at least slightly spaced away from the lower half, thereby allowing motive flow to enter the venturi passage. 
     Thus, a system comprising a vacuum generating device includes an upper half with surfaces identical to a lower half, and where the halves are aligned along a vertical axis, an annular venturi passage located between the upper and lower halves, the venturi passage being fluidly coupled to a passage configured to receive ambient air, and a vacuum consumption device being fluidly coupled to the annular venturi passage via interior passages of the upper half. The upper half comprises an upper apex and the lower half comprises a lower apex. A distance between the upper and lower halves is smallest between the upper and lower apices. The upper half is slidable parallel to the vertical axis and the lower half is stationary, and where a first position includes spacing the upper half away from the lower half and a second position includes pressing the upper apex of the upper half to the lower apex of the lower half. The second position further includes preventing ambient air flow to the annular venturi passage via sealing the annular venturi passage from the passage. The interior passages of the upper half include a first passage and a second passage, the first passage being cylindrical and located along the vertical axis, and where the second passage is annular and concentric with the first passage about the vertical axis. The first passage fluidly couples the vacuum consumption device to the annular venturi passage in the second position and the second passage fluidly couples the vacuum consumption device to the annular venturi passage in the first position. The lower half comprises an inner passage fluidly coupling the annular venturi passage to an intake manifold, and where vacuum from the intake manifold flows to the vacuum consumption device via the first passage. The vacuum generating device is a throttle and the passage is an intake passage. 
     Turning now to  FIG. 5  it shows an isometric view  500  of a vacuum generating device  510 . The vacuum generating device  510  may be used substantially similarly as the vacuum generating device  210  shown in the embodiment of  FIG. 2 . In one example, the vacuum generating device  510  differs from the vacuum generating device  210  in that it is fixed and does not comprise any sliding components. As such, the vacuum generating device  510  may only be used as an auxiliary vacuum generating device (e.g., vacuum pump  77  in the embodiment of  FIG. 1 ) while the vacuum generating device  210  may be used as a throttle (e.g., throttle  64  in the embodiment of  FIG. 1 ) or an auxiliary vacuum generating device (e.g., vacuum pump  77  in the embodiment of  FIG. 1 ). 
     In this way, a system (e.g., a vehicle) may comprise the vacuum generating device  210  functioning similarly to throttle  62  in intake passage  42  of  FIG. 1  and the vacuum generating device  510  functioning as an auxiliary vacuum generating device in an auxiliary passage completely outside of the intake passage. In one example, the vacuum generating device  210  and vacuum generating device  510  are coupled to different vacuum consumption devices (e.g., an EGR valve and a brake booster). In another example, the vacuum generating device  210  and the vacuum generating device  510  are coupled to the same vacuum consumption device. 
     As shown, vacuum generating device  510  is located in auxiliary passage  504 . The auxiliary passage  504  is located completely outside of passage  204  of  FIG. 2 . In some examples, both the auxiliary passage  504  and the passage  204  expel air to intake manifold  44  of  FIG. 1 . In other examples, the auxiliary passage  504  expels air to an ambient atmosphere through a grill located on a rear face of a vehicle. 
     An axis system  590  is shown comprising three axes, namely an x-axis parallel to the horizontal direction, a y-axis parallel to the vertical direction, and a z-axis perpendicular to the x- and y-axes. A direction of gravity is shown by arrow  599 , which is parallel to the y-axis. A vertical axis  595  is shown extending through a geometric center of the vacuum generating device  510  parallel to the y-axis. 
     The vacuum generating device  510  may be a partially hollow device configured to admit gas therethrough to provide vacuum to a vacuum consumption device  586 . The vacuum generating device  510  may expel the gas to an intake manifold of an engine (e.g., similar to throttle  62  of  FIG. 1 ), in one example. Alternatively, the vacuum generating device  510  may expel the gas to an ambient atmosphere. By doing this, the vacuum generating device  510  may be located in an auxiliary passage  504  with an inlet and an outlet fluidly coupled to the ambient atmosphere, and where the auxiliary passage  504  is fluidly sealed from an engine and/or other components of a vehicle excluding the vacuum consumption device  586 . 
     The vacuum generating device  510  comprises upper  520  and lower  530  halves aligned with one another along the vertical axis  595 . Upper body  522  and upper outer surface  524  of the upper half  520  are substantially identical to the lower body  532  and lower outer surface  534  of the lower half  530 . In one example, the upper  522  and lower  532  bodies are cylindrical and partially hollow for flowing air therethrough. Furthermore, the upper outer surface  524  and lower outer surface  534  are convex and form an annular venturi passage  550  located therebetween, as will be described below. In one example, outer surfaces of the upper  520  and lower  530  halves (e.g., upper  522  and lower  532  bodies, and upper outer  524  and lower outer  534  surfaces) are substantially identical to the outer surfaces of the upper  220  and lower  230  halves (e.g., upper  222  and lower  232  bodies, and upper outer  224  and lower outer  234  surfaces). Thus, venturi passage  550  is substantially identical to venturi passage  250 . In this way, only interior portions of the upper  520  and lower  530  halves and upper  220  and lower  230  halves are different. 
     Specifically, the lower half  530  comprises a lower outer surface  534  and a lower inner surface  536  angled oppositely toward one another. The lower outer  534  and lower inner  536  surfaces meet at a lower apex  538 . As such, the lower outer surface  534  corresponds to a venturi inlet  525  of the venturi passage  550 . The lower inner surface  536  corresponds to a venturi outlet  554 . The lower apex  558  corresponds to a venturi throat  556 . 
     Since outer surfaces of the upper  520  and lower  530  halves are substantially identical, the upper half  520  also comprises the upper outer surface  524  being oppositely angled to an upper inner surface with an upper apex  528  located at an intersection of the two. A distance between the upper half  520  and the lower half  530  is smallest between the upper apex  528  and the lower apex  538 . 
     The vacuum generating device  510  is located in a pipe  502 . Two embodiments of the pipe  502  are shown. A first embodiment  503  is shown in solid line and is concentric with the upper  520  and lower  530  halves about the vertical axis  595 . The first embodiment  503  is physically coupled to the lower half  530  below the lower outer surface  534 . Downstream of and/or vertically below the lower half  530 , an outlet conduit  508  fluidly couples the vacuum generating device  510  to an intake manifold (e.g., intake manifold  44  of  FIG. 1 ) with a diameter substantially equal to a greatest diameter of the lower half  530 . The upper half  520  is spaced away from and located wholly inside the first embodiment  503 . 
     A second embodiment  505  of the pipe  502  is shown in dashed lines and is perpendicular to the vertical axis  595 . The second embodiment  505  surrounds the upper  520  and lower  530  halves. Similar to the first embodiment  503 , the second embodiment  505  is physically coupled to the lower half  530  below the lower outer surface  534 . The upper half  520  is located completely inside of the second embodiment  505 , while the lower half  530  is only partially located inside the second embodiment  505 . The venturi passage  550  is completely located inside the second embodiment  505 . The upper half  520  is spaced away from the second embodiment  505  such that the upper body  522  does not touch interior surfaces of the second embodiment  505 . 
     The upper half  520  is fixed in the pipe  502  and does not move. In one example, a plurality of supports  506  and/or stand-offs  506  may physically couple the upper half  520  to the lower half  530 . In this way, the upper half  520  is cantilevered in the pipe  502 . Said another way, the upper half  520  is spaced away from the lower half  530  with no portions of the upper half  520  contacting any portions of the lower half  530 , and where stand-offs  506  are coupled to the upper  520  and lower  530  halves at opposite ends. Alternatively, the upper half  520  may also be coupled to the pipe  502  via one or more bores  582  coupling the conduit  580  to the pipe  502 . The conduit  580  fluidly couples the upper half  520  to the vacuum consumption device  586 , as will be described below. 
     The pipe  502  is configured to flow ambient air, whether in the first embodiment  503  or second embodiment  505 , to the venturi passage  550  and upper interior passage  542  of the upper half  520  via the auxiliary passage  504 . The ambient air may flow through a grill located on a front of a vehicle fluidly coupling auxiliary passage  504  to the ambient atmosphere. In one example, the auxiliary passage  504  may expel ambient air to the ambient atmosphere without flowing ambient air to the engine. Alternatively, the auxiliary passage  504  may flow ambient air and/or suck flow to an intake manifold of an engine. 
     Ambient air in the auxiliary passage  504  may flow to the outlet conduit  508  by flowing through the venturi passage  550  and/or the upper interior passage  542 . Both passages expel gas to a lower interior passage  544  of the lower half  530 , which expels gas to the outlet conduit  508 . The venturi passage  550  comprises a venturi inlet  552  located between the upper  524  and lower  534  outer surfaces, a venturi outlet  554  located between the upper and lower  536  inner surfaces, and a venturi throat  556  located between the upper  528  and lower  538  apices. As such, vacuum may be generated in the venturi throat  556  as static pressure decreases as it flows through the venturi throat  556 . 
     A combination of the upper  542  and lower  544  interior passages resemble a venturi passage along the vertical axis  595 . Thus, the upper interior passage  542  may be referred to as a second venturi inlet  542 , the lower interior passage  544  may be referred to as a second venturi outlet  544 , and the space between the upper  542  and lower  544  interior passages may be referred to as a second venturi throat  546 . Herein, the venturi passage  550  may be referred to as first venturi passage  550 , and the venturi passage created by the upper  542  and lower  55  interior passages may be referred to as a second venturi passage  540 . The second venturi throat  546  of the second venturi passage  540  is located interior to and/or adjacent to the venturi outlet  554 . In this way, vacuum generated by the second venturi passage  540  may increase a vacuum generated by the first venturi passage  550 , thereby allowing the first venturi passage  550  to provide a greater amount of vacuum to the vacuum consumption device  586  than the venturi passage  250  of  FIG. 2 . 
     The second venturi inlet  542  comprises an upper inlet  541  configured to receive ambient air from the auxiliary passage  504 . Air in the second venturi inlet  542  is expelled to the second venturi throat  546  via an upper outlet  543 . A diameter of the outlet  543  is less than a diameter of the inlet  541 . The outlet  543  faces the lower half  530 . Specifically, the upper outlet  543  is located directly across from a lower inlet  547  of the second venturi outlet  544 . Air in the second venturi outlet  544  is expelled to outlet conduit  508  via a lower outlet  549 . As shown, the lower outlet  549  extends into the outlet conduit  508 . However, it will be appreciated that the lower outlet  549  may not extend into the outlet conduit  508  without departing from the scope of the present disclosure. Due to the venturi shape of the venturi passage  540 , a diameter of the second venturi inlet  542  decreases from the upper inlet  541  to the upper outlet  543 . Oppositely, a diameter of the second venturi outlet  544  decreases from the lower inlet  547  to the lower outlet  549 . 
     Thus, the first venturi passage  550  is an annular venturi passage with an annular venturi inlet  552 , annular venturi outlet  554 , and annular venturi throat  556 . The first venturi passage  550  is concentric with the second venturi passage  540  about the vertical axis  595 . The second venturi passage  540  is parallel to the vertical axis  595  and traverses through the venturi outlet  554 . Specifically, the second venturi throat  546  is located directly along the annular venturi outlet  554 . Vacuum from the second venturi passage  540  pulls air through the annular venturi passage  550 , which in turn may result in a greater amount of vacuum generated in the annular venturi throat  556  compared to only one venturi passage being located in the vacuum generating device  510 . Vacuum generated by the first  550  and second  540  venturi passages flows to the vacuum consumption device  586  the upper half  520 , as will be described below. 
     An annular interior passage  570  is fluidly coupled to the vacuum consumption device  586  via the conduit  580 . As shown, the annular interior passage  570  is located wholly inside of the upper half  520 . The upper interior passage  542  and annular interior passage  570  are concentric about the vertical axis  595 . The upper interior passage  542  and annular interior passage  570  are wholly located inside the upper half  520 , with the annular interior passage  570  circularly surrounding the upper interior passage  542 . Air in the upper interior passage  542  does not mix with air in the annular interior passage  570  in the upper half  520 . The annular interior passage outlet  572  is located at the upper apex  528 . Thus, the upper apex  528  is completely open to the first venturi passage  550 . Vacuum may flow through the annular interior passage  570  to the vacuum consumption device  586  as suck flow flows from the vacuum consumption device  586 , through the annular interior passage  570 , and into the venturi throat  556 . 
     Turning now to  FIG. 6 , it shows a cross-sectional view  600  along a cutting plane N—N′ of  FIG. 5 , including example motive air, suck flow, and vacuum flow through the vacuum generating device  510 . As described above, the vacuum generating device  510  is fixed and does not move. In this way, the vacuum generating device  510  only generates vacuum when ram air is flowing through the auxiliary passage  504 . 
     Ambient air  650  flows through the pipe  502  toward the vacuum generating device  510 . The first venturi passage  550  and second venturi passage  540  receive ambient air flow in different directions. Ambient air flowing parallel to the vertical axis  595  may readily enter the second venturi passage  540  via the upper inlet  541  of the second venturi inlet  542 . The ambient air flows through the second venturi passage  540  by passing through the second venturi inlet  542 , through second venturi throat  546 , and through the second venturi outlet  544 . The second venturi throat  546  generates vacuum  654 , which may promote ambient air to flow radially inward into the first venturi passage  550 . Ambient air  650  flows through the first venturi inlet  552 , venturi throat  556 , and venturi outlet  554 . As such, ambient air  650  from the first  550  and second  540  venturi passages merges in the second venturi throat  646 . Vacuum  654  flows from the first venturi throat  556  into the annular interior passage  570 , through the conduit  580 , and to the vacuum consumption device  586 . In response, suck flow  652  flows from the vacuum consumption device  586 , through the annular interior passage  570 , and into the first venturi throat  556 . Suck flow  652  mixes with ambient air  650  in the second venturi throat  646  adjacent the upper inner surface  526  and lower inner surface  536 , before flowing into the second venturi outlet  644 . The mixture of ambient air  650  and suck flow  652  are expelled to the outlet conduit  508 , where they may be directed to the ambient atmosphere. 
     In one example, additionally or alternatively, the auxiliary passage  504  is fluidly coupled to an intake manifold (e.g., intake manifold  44  of  FIG. 1 ). As such, suck flow from the vacuum consumption device  586  may mix with suck flow from the vacuum consumption device  140  of  FIGS. 1 and 2  in the intake manifold  44 . 
     As shown, the vacuum generating device  510  is static. Ram air flows through the vacuum generating device  510  when a vehicle moves, resulting in vacuum flowing to the vacuum consumption device  586 . In some examples, a fan may be provided upstream of the vacuum generating device  510  to provide air flow during stationary vehicle operating conditions. Upstream and downstream refer to a direction of air flow. Therefore, the fan may allow the vacuum generating device  510  to generate vacuum during vehicle stationary and vehicle moving conditions. 
     Thus, a system comprising an auxiliary passage fluidly separated from intake and exhaust passages of an engine may further include a vacuum generating device located in the auxiliary passage. The vacuum generating device produces vacuum as air flows through the auxiliary passage via first and second venturi passages; the first venturi passage being annularly located between identically shaped upper and lower halves of the vacuum generating device, the second venturi passage traversing through the upper and lower halves along a vertical axis. The vacuum generating device further comprises an annular interior passage circumferentially surrounding the second venturi passage inside the upper half, and where the annular interior passage is configured to flow vacuum from the first venturi passage to a vacuum consumption device. The vacuum generating device is fixed and the upper and lower halves are coupled via one or more stand-offs. The second venturi passage comprises a second venturi throat fluidly coupled to a first venturi outlet of the first venturi passage, and where vacuum from the second venturi throat is supplied to the first venturi throat. The first venturi passage is annular with a first venturi outlet located proximal to the vertical axis and a first venturi inlet located farthest away from the vertical axis. The second venturi passage comprises a second venturi inlet located inside the upper half, a second venturi outlet located inside the lower half, and a second venturi throat located between the upper and lower halves. The upper half is wholly located in a pipe of the auxiliary passage, and where the lower half is partially located in the pipe. The vacuum consumption device is one or more of a brake booster, EGR valve, and fuel-vapor canister. 
     Turning now to  FIG. 7 , it shows a system  700  comprising an engine  10 , vacuum generating device  210 , and vacuum generating device  510 . As such, components previously presented may be similarly numbered and not reintroduced. In one example, the system  700  is a vehicle. Alternatively, the system  700  may be another device configured to draw in air and utilize vacuum consuming devices. Components described as being located at a front end are on a left side of the figure and components described as being located at a rear end are on a right side of the figure. 
     A first grill  702  is configured to admit motive air to the vacuum generating device  210  located in intake passage  42 . Thus, in the embodiment of  FIG. 7 , the vacuum generating device  210  is used as throttle  64  of  FIG. 1 . In this way, the vacuum generating device  210  is adapted to adjust intake air flow to the engine and simultaneously replenish a vacuum of the vacuum consumption device  140 . 
     A second grill  704  is configured to admit ram air to the vacuum generating device  510  located in auxiliary passage  504 . As shown, the auxiliary passage  504  is fluidly separated from the intake passage  42 . Thus, air in the auxiliary passage  504  does not mix with air in the intake passage  42 . A first optional passage  712  is shown connecting the auxiliary passage  504  to the intake manifold  44 . A second optional passage  714  is shown downstream of the first optional passage  712 , fluidly coupling the auxiliary passage  504  to exhaust passage  48 . In some examples, a valve may be located in the second optional passage  714 , where the valve is configured to open during regeneration of the aftertreatment device  70 . In this way, air from the auxiliary passage  504  flows to the aftertreatment device  70  when the valve is in an open position. 
     Thus, a method comprises replenishing vacuum in a vacuum consumption device by flowing air through an annular venturi passage located between identically shaped upper and lower halves of a vacuum generating device. The annular venturi passage comprises an annular venturi throat located between upper and lower apices of the upper and lower halves, respectively, and where the vacuum consumption device is fluidly coupled to the annular venturi throat through an annular passage of the upper half. The upper and lower halves are cylindrical and aligned with one another along a vertical axis, and where the upper and lower halves comprise protrusions extending toward one another. The protrusions form the annular venturi passage. The upper and lower halves are partially hollow and comprise passages located therein for flowing air, vacuum, and suck flow. 
     In this way, vacuum is provided to a vacuum consumption device via a vacuum generating device. Ambient air flows through the vacuum generating device, which comprises one or more venturi passages for producing vacuum. Thus, electronic valves and/or motors may not be coupled to the vacuum generating device, thereby reducing a packaging of the vacuum generating device. Additionally, a portion of the vacuum generating device may be spontaneously moveable based on vehicle operating conditions, such that the vacuum generating device may be used as a throttle in an intake passage. Alternatively, the vacuum generating device may be fixed and located in an auxiliary passage fluidly separated from other passages of a vehicle. The technical effect of providing one or more vacuum generating devices is to replenish vacuum of the vacuum consumption device through a plurality of vehicle operating conditions. 
     In an alternate embodiment a system comprises a throttle configured to provide vacuum to a first vacuum consumption device when air flows through an intake passage, a vacuum generating device configured to provide vacuum to a second vacuum consumption device when air flows through an auxiliary passage, and the throttle and vacuum generating device comprise upper and lower halves aligned along a common axis with annular venturi passages located therebetween, and where the upper half of the throttle is slidable and the halves of the vacuum generating device are fixed. 
     Note that the example control and estimation routines included herein can be used with various engine and/or vehicle system configurations. The control methods and routines disclosed herein may be stored as executable instructions in non-transitory memory and may be carried out by the control system including the controller in combination with the various sensors, actuators, and other engine hardware. The specific routines described herein may represent one or more of any number of processing strategies such as event-driven, interrupt-driven, multi-tasking, multi-threading, and the like. As such, various actions, operations, and/or functions illustrated may be performed in the sequence illustrated, in parallel, or in some cases omitted. Likewise, the order of processing is not necessarily required to achieve the features and advantages of the example embodiments described herein, but is provided for ease of illustration and description. One or more of the illustrated actions, operations and/or functions may be repeatedly performed depending on the particular strategy being used. Further, the described actions, operations and/or functions may graphically represent code to be programmed into non-transitory memory of the computer readable storage medium in the engine control system, where the described actions are carried out by executing the instructions in a system including the various engine hardware components in combination with the electronic controller. 
     It will be appreciated that the configurations and routines disclosed herein are exemplary in nature, and that these specific embodiments are not to be considered in a limiting sense, because numerous variations are possible. For example, the above technology can be applied to V-6, I-4, I-6, V-12, opposed 4, and other engine types. The subject matter of the present disclosure includes all novel and non-obvious combinations and sub-combinations of the various systems and configurations, and other features, functions, and/or properties disclosed herein. 
     The following claims particularly point out certain combinations and sub-combinations regarded as novel and non-obvious. These claims may refer to “an” element or “a first” element or the equivalent thereof. Such claims should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and sub-combinations of the disclosed features, functions, elements, and/or properties may be claimed through amendment of the present claims or through presentation of new claims in this or a related application. Such claims, whether broader, narrower, equal, or different in scope to the original claims, also are regarded as included within the subject matter of the present disclosure.