SUPER ASPIRATOR WITH INTEGRATED DUAL FLOW SHUT OFF

Abstract

In one embodiment, an aspirator is provided including a venturi pipe having a converging section including a converging inlet and a converging outlet, and a diverging section having a diverging inlet and a diverging outlet. The converging outlet is in fluid communication with the diverging inlet. A throat is positioned between the converging outlet and the diverging inlet. A shut off valve is movable between an open position and a closed position. The shut off valve is positioned within the throat when in the closed position.

Description

BACKGROUND OF THE DISCLOSED EMBODIMENTS

Internal combustion engines have long employed air flow conduits to provide vacuum assist for automobile subsystems, such as brakes, automatic transmissions and others. These systems often employ check valves located along the air flow conduit to prevent subsystem back pressure from reaching the engine.

A check valve unit comprises an inlet and an outlet connected to each other via a main air channel. In the assembled state or in case of utilization, the inlet is connected to the operating system and the outlet to the suction system. A first check valve is located in the main air channel. This prevents the negative pressure from escaping once it has been produced in the operating system in case that pressure rises in the suction system. Furthermore, one single outlet channel which branches off from the main air channel downstream of the first check valve and lets out into the atmosphere is provided with the check valve unit. A venturi pipe or a narrowing of the cross-section is provided in this outside channel. This narrowing of the cross-section is connected via a channel, hereinafter the venturi channel, to the main air channel at a point located upstream of the first check valve.

In the known check valve units, it is a disadvantage that air is constantly sucked in through the outside channel. This is especially detrimental with combustion engines where the air mass flowing through the choke valve of the air suction pipe is used for engine control or to optimize the combustion process. The outside channel containing the venturi pipe can be closed off by a sliding valve when the system pressure of the operating system has reached its target value.

SUMMARY OF THE DISCLOSED EMBODIMENTS

In one embodiment an aspirator is provided including a venturi pipe having a converging section including a converging inlet and a converging outlet, and a diverging section having a diverging inlet and a diverging outlet. The converging outlet is in fluid communication with the diverging inlet. A shut off valve is movable between an open position and a closed position. The shut off valve may have an aperture extending therethrough. In the closed position, the aperture is in fluid communication between converging outlet and the diverging inlet. When the shut off valve is in the open position, the aspirator has high mass flow performance to operate devices such as brakes. When the shut off valve is in the closed position, flow through the aspirator is reduced, but not entirely shut off. Accordingly, the shut off valve can be opened to evacuate a brake booster quickly, and closed to reduce an amount of leakage through the system. However, the aperture allows enough leakage to work the brakes if the shut off valve fails and does not open.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:

FIG. 1 illustrates a front view of prior art check valve aspirator.

FIG. 2 illustrates a cross-sectional view of a prior art check valve aspirator.

FIG. 3 illustrates a top view of a prior art check valve aspirator.

FIG. 4 illustrates a cross-sectional view of an aspirator formed in accordance with an embodiment and having a shut off valve in a closed position.

FIG. 5 illustrates a cross-sectional view of the aspirator shown in FIG. 3 and having the shut off valve in the open position.

FIG. 6 illustrates a cross-sectional view of the shut off valve shown in FIG. 3 in the closed position.

FIG. 7 illustrates a cross-sectional view of the shut off valve shown in FIG. 3 in the open position.

FIG. 8 illustrates a cross-sectional view of an aspirator formed in accordance with an embodiment and having a shut off valve in a closed position.

FIG. 9 illustrates a cross-sectional view of the aspirator shown in FIG. 7 and having the shut off valve in the open position.

FIG. 10 illustrates a cross-sectional view of the shut off valve shown in FIG. 7 in the closed position.

FIG. 11 illustrates a cross-sectional view of the shut off valve shown in FIG. 7 in the open position.

DETAILED DESCRIPTION OF THE DISCLOSED EMBODIMENTS

For the purposes of promoting an understanding of the principles of the invention, reference will now be made to the embodiment illustrated in the drawings, and specific language will be used to describe that embodiment. It will nevertheless be understood that no limitation of the scope of the invention is intended. Alterations and modifications in the illustrated device, and further applications of the principles of the invention as illustrated therein, as would normally occur to one skilled in the art to which the invention relates are contemplated and desired to be protected. Such alternative embodiments require certain adaptations to the embodiments discussed herein that would be obvious to those skilled in the art.

A prior art check valve aspirator is illustrated in FIG. 1. The internal configuration and operation of the prior art aspirator is shown and described in U.S. Pat. No. 5,291,916. FIGS. 1-3 are reproductions of the figures from U.S. Pat. No. 5,291,916. The prior art check valve aspirator is commercially available from Nyloncraft Incorporated (616 W. McKinley Ave, Mishawaka, Ind. 46545).

Referring to FIGS. 1-3, check. valve 10 is normally employed in an internal combustion engine in the air flow line between the engine block and the air intake port at the full mixing port, normally a carburetor or fuel injection port. For clarity, the engine, carburetor, hose connections, and subsystems are not shown, and it is understood that these ports are common to the internal combustion engines found in almost all vehicles.

The air flow system in the typical internal combustion engine operates on the principle that as the engine operates, a partial vacuum is created which pulls air through the air intake port of the carburetor of fuel injector to aid in proper fuel combustion. This vacuum has been found to be useful in supplementing vacuum assist subsystems in the vehicle, particularly brakes, automatic transmissions and most recently, air conditioners. Check valve 10 provides the connection between the main airway and the subsystem and serves to inhibit back pressure from the subsystem from disturbing airflow through the main airway.

Check valve 10 shown in the drawings include a substantially one piece valve body 12 which is preferably formed of a top valve half 14 and a bottom valve half 16. The designations of top and bottom halves are for descriptive purposes only and are not limitative of the orientation of valve 10 in the engine compartment. Preferably, top valve half 14 is joined to bottom valve half 16 by sonic welding, heating or other conventional method prior to its use.

Bottom valve half 16 includes an air inlet 18 and an air outlet 20 which are in direct air flow communication via air passageway 22. In typical use in an internal combustion engine, air inlet 18 will be connected via a conduit (not shown) to the air intake port in the engine carburetor or other function member (not shown). Air outlet 20 is preferably connected via a conduit (not shown) to the vacuum port of the engine block (not shown).

As shown, bottom valve half 16 also includes lower valve seats 24, 26. Each lower valve seat 24, 26 is defined by a continuous outer wall 28, 29, and a bottom wall 30, 31. A bore 32, 33 is defined in each lower valve seat 24, 26 to allow for air flow communication with air passageway 22. Each outer wall 28, 29 may include stepped portion 58, 59 as shown to provide for ease in mating with upper valve seats 25, 27, as described later in this specification. A plurality of radially spaced fingers 34, 35 extend integrally upwardly from each bottom wall 30, 31 and serve to support a flexible seal member 36, 37. Air passageway 22 has an opening 38 which allows for air communication between the passageway and valve seat 24.

As shown in FIG. 2, air passageway 22 is defined by a tapering outer passage 40 which narrows from inlet port 18 up to the opening 38, and a widening passage 42 from opening 38 to the intersection of passageway 22 and valve seat 26. This configuration of passageway 22 is commonly known as a venturi conduit, whose functions are well known to those skilled in the art.

Upper valve half 14 is adopted to mate with lower valve half 14 to form check valve 10. Upper valve half 14 as shown includes inlet 44 and inlet 46 which may be connected in air flow communication by air passageway 48. In a typical connection to an internal combustion engine, inlet 44 will be connected via an air hose (not shown) to a brake system (not shown) and inlet 46 will be either capped or connected to another subsystem of a vehicle, such as the air conditioner compressor (not shown).

As shown, upper valve half 14 includes valve seats 25, 27. Each upper valve seat 25, 27 is defined by continuous outer wall 50, 51 and bottom wall 52, 53. A bore 54, 55 is defined in each upper valve seat 25, 27 to allow for air communication with air passageway 48 and inlets 44, 46. Bottom walls 52, 53 are preferably of a smooth concave configuration as shown with bores 54, 55 of a slightly lesser diameter than that of seals 36, 37. Each outer wall 50, 51 preferably has a circumferential groove 56, 57 substantially complemental to the stepped portion 58, 59 of the lower valve seats 24, 26.

Check valve 10 is assembled by aligning valve seats 24, 26 with valve seats 25, 27 such that stepped portions 58, 59 are aligned with grooves 56, 57. Seals 36, 37 are placed on fingers 34, 35, and the valve parts 14, 16 are then pressed together and joined as by sonic welding or other common method. The preferred method of joining valve parts 14, 16 will generally depend on the material used to form the valve parts, in this embodiment an injection molded heat resistant, rigid plastic. It is understood that an suitable plastic or metal or other compound may be used in forming check valve 10, which is now ready for implementation in the internal combustion engine as follows.

With the above hose hook-ups mentioned above, check valve 10 functions as follows. As the engine (not shown) operates, it draws air through inlet 18, passageway 22 and outlet 20. This creates a partial vacuum valve seats 24-27 and passageway 48 to draw seals 36, 37 downward against fingers 34, 35. Due to the spacing of fingers 34, 35 (FIG. 3) free air flow from passageway 48 to passageway 22 is allowed. The partial vacuum created by the operation of the engine serves in the vacuum assistance of the operation of the brake, and, if desired, air conditioning subsystems (not shown) in a common manner.

If for any reason, back pressure in one of the subsystems is generated to create a positive air flow through passageway 48 to inlets 44, 46 a reverse flow vacuum is generated to draw seals 36, 37 tight against valve seat bottom walls 52, 53 to prevent the vacuum from interfering with the above described air flow through passageway 22. The functioning of check valve 10 as thus far described is well-known to those skilled in the art.

As shown in FIG. 2, the tapering and widening passageways 40, 42 create the novel venturi effect on the partial vacuum generated during the operation of the engine (not shown). By their configurations, passageways 40, 42 allow for a marked increase in the velocity with reduced pressure of the air passing through passageway 42. Due to the connection of passageway 22 and valve seats 24, 25, a marked increase in the amount of air drawn through passageway 48 and valve seats 25, 24 provides a significant boost in the vacuum assist for the subsystems (not shown) As an example, check valve 10 was tested in a conventional internal combustion engine which normally pulls a vacuum of about seven inches of mercury (7″ Hg). The observed vacuum at outlet 44 with valve 10 in place was eighteen inches of mercury (18″ Hg) which amounts to a 157% increase generated due to the use of valve 10 with its venturi effect passageways 40, 42.

As illustrated in FIGS. 4-7, an aspirator 210 is provided that may be electronically operated based on signals received from sensors within the engine. The aspirator 210 includes a vacuum channel 216 and an outside air channel 218. The vacuum channel 216 extends between an inlet 212 and a bypass channel 213, and the outside air channel 218 extends between an inlet port 215 and an outlet port 236. The bypass channel 213 fluidly couples the vacuum channel 216 and the outlet port 236. The vacuum channel 216 and the outside air channel 218 are further fluidly coupled by a venturi channel 240. A venturi pipe 220 is located in the outside air channel 218. The venturi pipe 220 includes converging section 222 and a diverging section 224. A throat 226 connects the converging section 222 and the diverging section 224. The converging section 222 extends between a converging inlet 228 and a converging outlet 230. The converging section 222 narrows from the converging inlet 228 to the converging outlet 230. In particular, the converging inlet 228 has a diameter D₁ that is greater than a diameter D₂ of the converging outlet 230. The diverging section 224 includes and diverging inlet 232 and a diverging outlet 234. The diverging section 224 widens from the diverging inlet 232 to the diverging outlet 234. In particular, the diverging inlet 232 has a diameter D₃ that is less than a diameter D₄ of the diverging outlet 234. The throat 226 extends between the converging outlet 230 and the diverging inlet 232.

A shut off valve 250 (illustrated in detail in FIGS. 6 and 7) is positioned between the converging outlet 230 and the diverging inlet 232. The shut off valve 250 is in fluid communication with the converging outlet 230 and the diverging inlet 232. In particular, the shut off valve 250 is positioned to close the throat 226 of the venturi pipe 220. The shut off valve 250 is movable between an open position 221 (shown in FIGS. 5 and 7) and a closed position 223 (shown in FIGS. 4 and 6), wherein in the open position 221, the throat 226 is open, and in the closed position 223, the shut off valve 250 is positioned in the throat 226. The shut off valve 250 is moved between the open position 221 and the closed position 223 by a solenoid 252 positioned adjacent to and coupled to the aspirator 210. The solenoid includes upper bumpers 270 and lower bumpers 272 that the shut off valve 250 contacts when moving between the open position 221 and the closed position 223. In particular, in the open position 221, the shut off valve 250 contacts the upper bumpers 270, and in the closed position 223, the shut off valve 250 contacts the lower bumpers 272. The bumpers 270 and 272 reduce noise when the shut off valve 250 moves between the open position 221 and the closed position 223. In one embodiment, the bumpers 270 and 272 are formed from fluorosilicone rubber.

The shut off valve 250 may be electronically operated based upon signals received from sensors within the engine 80, shown in FIG. 14. When the brake booster vacuum 84, shown in FIG. 14, is equalized with the engine vacuum, the shut off valve closes to prevent air flow through the venturi throat 226 but to allow air flow through the bypass valve 213. In one embodiment, the shut off valve 250 remains open during an ignition cold start to allow the engine intake manifold 80 to draw air from an air intake 82, shown in FIG. 14, through the venturi pipe 220 to create a vacuum within the brake booster 84. In one embodiment, when the engine throttle valve is open, the shut off valve 250 will open if the brake booster vacuum is less than 35 kPa, and the shut off valve 250 will close if the brake booster pressure is greater than 35 kPa, regardless of the intake manifold pressure. In one embodiment, when the engine throttle valve is closed and the engine intake manifold pressure is less than 50 kPa, the shut off valve 250 will open if the brake booster pressure is less than 35 kPa, and the shut off valve 250 will close if the brake booster pressure is greater than 35 kPa. In one embodiment, when the engine throttle valve is closed and the engine intake manifold pressure is greater than 50 kPa, the shut off valve 250 will close regardless of the brake booster pressure. It should be noted that the examples given herein are exemplary only, and the pressures described may vary based on application and engine type.

The solenoid 252 requires a low force to move the shut off valve 250 between the open position 221 and the closed position 223. Because of the low force required, the solenoid is capable of being sized relatively small when compared to other shut off valves. In one embodiment, the shut off valve 250 will not open during a reverse flow event, such as may be created by a turbocharger or a backfire.

When airflow through the venturi is completely shut off, automobile subsystems, such as brakes, may have limited functionality. Accordingly, if the sliding valve becomes stuck or the actuator of the valve malfunctions, the vehicle is with limited control of the automobile subsystems, which can be dangerous and costly. As illustrated in FIGS. 8-11, an aspirator 110 includes a vacuum channel 116 and an outside air channel 118. The vacuum channel 116 extends between an inlet 112 and a bypass channel 113, and the outside air channel 118 extends between an inlet port 115 and an outlet port 136. The bypass channel 113 fluidly couples the vacuum channel 116 and the outlet port 136. The vacuum channel 116 and the outside air channel 118 are further fluidly coupled by a venturi channel 140. A venturi pipe 120 is located in the outside air channel 118. The venturi pipe 120 includes converging section 122 and a diverging section 124. A throat 126 connects the converging section 122 and the diverging section 124. The converging section 122 extends between a converging inlet 128 and a converging outlet 130. The converging section 122 narrows from the converging inlet 128 to the converging outlet 130. In particular, the converging inlet 128 has a diameter D₁₁ that is greater than a diameter D₁₂ of the converging outlet 130. The diverging section 124 includes a diverging inlet 132 and a diverging outlet 134. The diverging section 124 widens from the diverging inlet 132 to the diverging outlet 134. In particular, the diverging inlet 132 has a diameter D₁₃ that is less than a diameter D₁₄ of the diverging outlet 134. The throat 126 extends between the converging outlet 130 and the diverging inlet 132.

A shut off valve 150 (illustrated in detail in FIGS. 10 and 11) is positioned between the converging outlet 130 and the diverging inlet 132. The shut off valve 150 is in fluid communication with the converging outlet 130 and the diverging inlet 132. In particular, the shut off valve 150 is positioned to close the throat 126 of the venturi pipe 120. The shut off valve 150 is movable between an open position 121 (shown in FIGS. 9 and 11) and a closed position 123 (shown in FIGS. 8 and 10), wherein in the open position 121, the throat 126 is open, and in the closed position 123, the shut off valve 150 is positioned in the throat 126. The shut off valve 150 is moved between the open position 121 and the closed position 123 by a solenoid 152 positioned adjacent to and coupled to the aspirator 110. The solenoid includes upper bumpers 170 and lower bumpers 172 that the shut off valve 150 contacts when moving between the open position 121 and the closed position 123. In particular, in the open position 121, the shut off valve 150 contacts the upper bumpers 170, and in the closed position 123, the shut off valve 150 contacts the lower bumpers 172. The bumpers 170 and 172 reduce noise when the shut off valve 150 moves between the open position 121 and the closed position 123. In one embodiment, the bumpers 170 and 172 are formed from fluorosilicone rubber.

The shut off valve 150 includes an aperture 154 extending therethrough. In the open position 121, as illustrated in FIG. 12, the shut off valve 150 does not block any of the venturi pipe 120. The aperture 154 size is determined by tolerable flow rate for the engine. In the closed position 123, as illustrated in FIG. 13, the aperture 154 allows fluid communication between converging outlet 130 and the diverging inlet 132. The aperture 154 has an upstream end 156 position adjacent the converging outlet 130 in the closed position 123. The upstream end 156 has a diameter D₁₅ that is approximately the same as a diameter D₁₂ of the converging outlet 130. The aperture 154 also includes a downstream end 158 positioned adjacent the diverging inlet 132 in the closed position 123. In one embodiment, the downstream end 158 has a diameter D₁₆ that may be less than a diameter D₁₃ of the diverging inlet 132. The aperture 154 converges from the converging outlet 130 to the diverging inlet 132 in the closed position 123. In the closed position 123 an opening 180 in the shut off valve 150 also allows air to leak between the converging section 122 and the vacuum channel 116 through the valve 140.

When the shut off valve 150 is in the open position 121, a first volume of air flows from the converging outlet 130 to the diverging inlet 132. When the shut off valve 150 is in the closed position 123, a second volume of air flows from the converging outlet 130 to the diverging inlet 132. The first volume of air is greater than the second volume of air. When the shut off valve 150 is in the open position 121, air flows from the converging outlet 130 to the diverging inlet 132 at a first flow. When the shut off valve 150 is in the closed position 123, air flows from the converging outlet 130 to the diverging inlet 132 at a second flow rate. The second flow rate is less than the first flow rate. Air leaks through the aperture 154 when the shut off valve 150 is in the closed position 123.

When the shut off valve 150 is in the open position 121, the aspirator 110 has high mass flow performance to operate devices such as brakes. When the shut off valve 150 is in the closed position 123, flow through the aspirator 110 is reduced, but not entirely shut off. Accordingly, the shut off valve 150 can be opened to evacuate a brake booster quickly, and closed to reduce an amount of leakage through the system. However, the aperture 154 allows enough leakage to work the brakes or other subsystems if the shut off valve 150 fails and does not open.

The shut off valve 150 may be electronically operated based upon signals received from sensors within the engine. When the brake booster vacuum is equalized with the engine vacuum, the shut off valve closes to prevent air flow through the venturi throat 126 but to allow air flow through the bypass valve 140. In one embodiment, the shut off valve 150 remains open during an ignition cold start to allow the engine intake manifold to draw air through the venturi pipe 120 to create a vacuum within the brake booster. In one embodiment, when the engine throttle valve is open, the shut off valve 150 will open if the brake booster vacuum is less than 35 kPa, and the shut off valve 150 will close if the brake booster pressure is greater than 35 kPa, regardless of the intake manifold pressure. In one embodiment, when the engine throttle valve is closed and the engine intake manifold pressure is less than 50 kPa, the shut off valve 150 will open if the brake booster pressure is less than 35 kPa, and the shut off valve 150 will close if the brake booster pressure is greater than 35 kPa. In one embodiment, when the engine throttle valve is closed and the engine intake manifold pressure is greater than 50 kPa, the shut off valve 150 will close regardless of the brake booster pressure. It should be noted that the examples given herein are exemplary only, and the pressures described may vary based on application and engine type.

While the invention has been illustrated and described in detail in the drawings and foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected.

Claims

1. An aspirator comprising: a venturi pipe having a converging section including a converging inlet and a converging outlet, and a diverging section having a diverging inlet and a diverging outlet, the converging outlet in fluid communication with the diverging inlet;a throat positioned between the converging outlet and the diverging inlet;a shut off valve movable between an open position and a closed position, the shut off valve positioned within the throat when in the closed position.

2. The aspirator of claim 1, wherein the shut off valve has an aperture extending therethrough, wherein, in the closed position, the aperture is in fluid communication between converging outlet and the diverging inlet.

3. The aspirator of claim 2, wherein the aperture has an upstream end position adjacent the converging outlet, the upstream end having a diameter that is approximately the same as a diameter of the converging outlet.

4. The aspirator of claim 2, wherein the aperture has a downstream end positioned adjacent the diverging inlet, the downstream end having a diameter that is less than a diameter of the diverging inlet.

5. The aspirator of claim 2, wherein the aperture converges from the converging outlet to the diverging inlet.

6. The aspirator of claim 2, wherein, in the open position, a first volume of air flows from the converging outlet to the diverging inlet, and in the closed position, a second volume of air flows from the converging outlet to the diverging inlet, the first volume of air being greater than the second volume of air.

7. The aspirator of claim 2, wherein air leaks trough the aperture when the shut off valve is in the closed position.

8. The aspirator of claim 2, wherein, in the open position, air flows from the converging outlet to the diverging inlet at a first flow rate, and in the closed position, air flows from the converging outlet to the diverging inlet at a second flow rate, the second flow rate being less than the first flow rate.

9. The aspirator of claim 1, wherein the shut off valve is moved between the open position and the closed position by a solenoid.

10. The aspirator of claim 9, wherein the solenoid includes bumpers that reduce noise when the shut off valve moves between the open position and closed position.

11. An aspirator comprising: a valve body having a first air inlet port;an air outlet port in air flow communication with the first air inlet port to define an air passageway;a second air inlet port in air flow communication with the first air inlet port and the air outlet port wherein air is drawn from the second air inlet port towards the air outlet port;a valve positioned between the air passageway and the second air inlet port for inhibiting air flow from the air passageway through the second air inlet port, wherein the air passageway includes a venturi conduit positioned between the first air inlet port and the outlet port, the venturi conduit constituting means for enhancing air flow through the outlet port with a corresponding enhancement of air drawn from the second air inlet port towards the outlet port, the valve including a valve seat positioned between the first and second inlet ports having an opening communicating with the air passageway;a flexible seal means positioned in the valve seat for responding to air exiting the second air inlet port under outside vacuum influence and for seating against the valve seat to prevent air flow from the air passageway from exiting through the second air inlet port, the venturi conduit positioned immediately adjacent the valve seat opening to provide maximum vacuum boost through the valve seat; anda shut off valve movable between an open position and a closed position, the shut off valve positioned within the venturi conduit when in the closed position.

12. The aspirator of claim 11 further comprising a third air inlet port in air flow communication with the second air inlet port to define a second air passageway in the valve body, the valve means positioned between the first-mentioned air passageway and the second air passageway.

13. The aspirator of claim 12 wherein the valve means includes first and second spaced valve seats, each valve seat including a flexible seal means positioned in the valve seat for responding to air exiting one of the second and third air inlet ports under outside vacuum influence and for seating against its associated valve seat to prevent air flow from the first-mentioned passageway from exiting through its respective second and third air inlet ports.

14. The aspirator of claim 13 wherein the venturi conduit has a tapered central portion of narrowed diameter immediately adjacent the valve seat opening.

15. The aspirator of claim 11 further comprising a check valve positioned within the valve seat, the check valve having a scalloped diaphragm.