Compact ejector system for a turbocharged combustion engine

Abstract

Compact ejector for a canister purge system of a turbocharged engine (10), comprising: a flange (152); a venturi tube (170) coupled to the flange (152); and a first and a second tube (160; 162) extending through the flange (152), wherein: the first tube (160) is fluidly coupled to one end of the Venturi tube (170); the second tube (162) is fluidly coupled to a downstream end of a throat (184) of the venturi tube (170); the ejector comprises a first and a second piece coupled together; the venturi tube (170) comprises a first and a second piece coupled together; the first piece comprises the first and second tubes (160; 162), the flange (152) and an upper portion of the venturi tube (170); and the second piece comprises a lower section of the Venturi tube (170).

Description

[0001] The present disclosure relates to a vapor venting ejector system for a turbocharged internal combustion engine and, on the other hand, relates to an ejector for assisting in venting during turbocharged operation.

[0002] Vehicles are equipped with an evaporative emission control system that captures fuel vapors from the vehicle's fuel tank and stores them in a canister containing activated carbon particles or other suitable media. The fuel vapors are absorbed into the activated carbon particles. To prevent the canister from becoming overloaded, so that the activated carbon particles no longer have the capacity to absorb fuel vapors, the canister is periodically purged.

[0003] In a naturally aspirated internal combustion engine, the pressure in the intake manifold is reduced. This vacuum is used to draw fresh air through the canister. The vapor-laden air is then introduced into the engine and burned. A purge valve or port is provided that fluidly couples the canister to the engine intake when purging is desired.

[0004] In turbocharged engines—i.e., those with a turbocharger, supercharger, or forced induction by any suitable device—the pressure in the engine's intake is often above atmospheric pressure, reducing the available time for scavenging. To create a vacuum to drive a scavenging flow, a pipe with a throat (a reduced-diameter section) creates a higher flow velocity, through which the vacuum is created. The component incorporating the throat is called an ejector or aspirator.

[0005] An example of a state-of-the-art design in Fig. 1. An engine 10 has an air intake system including a manifold 12 and a throttle body 14. The throttle body 14 has an air passage 16 and a throttle valve 18 to control the amount of air flowing into the manifold 12. The throttle body 14 has an inlet 20 fluidly connected to an outlet 22 of a turbocharger assembly 24.

[0006] The turbocharger assembly 24 includes a compressor 26 and a turbine 28. The compressor 26 and the turbine 28 are both mounted on a common shaft 30. Exhaust gases are directed through a duct 32 to the turbine 28 and discharged through an outlet pipe 34.

[0007] The compressor 26 takes in air from an intake port 36. The air is pressurized by the compressor 26 and discharged into the outlet 22 and then into the throttle body 14 or charge air cooler, into the manifold 12, and then into the engine 10.

[0008] Modern engines are equipped with evaporative emission control systems that include a fuel vapor storage canister 38. The vapor storage canister 38 contains a quantity of activated carbon particles 40 or other suitable adsorbent material. Activated carbon absorbs and stores fuel vapors. The activated carbon particles 40 are fixed between a lower filter 42 and an upper filter 44. Fuel vapors and air are directed into the interior of the canister 38.

[0009] The activated carbon 40 has a limited storage capacity for fuel vapor. Therefore, the canister is periodically purged to remove fuel vapor from the activated carbon by drawing air from the atmosphere into the canister and through the activated carbon bed. Atmospheric air flows through and captures fuel vapor molecules in an adsorption process. The fuel-laden air is drawn into the combustion chambers of the engine 10 and burned. An air inlet 46 is provided to admit purge air to the engine canister 38. Air from the inlet 46 flows downward through a duct 48 to a space 50 below the filter 42 and above the bottom of the canister 38.

[0010] Canister 38 has an outlet opening 52 to allow purge air and fuel vapors to be discharged from canister 38. Normally, purge air and fuel vapor are desorbed from the activated carbon through a tube 54 to one of tubes 56 or 58; alternatively, the tube may be coupled to the intake manifold. When engine 10 is idling, throttle valve 18 assumes a position 18', and the interior of throttle body 14 downstream of throttle valve 18 is under vacuum. During this period, purge air is drawn from tube 56 through an orifice 60. Excessive purging can impair engine performance. A fuel vapor control valve 62 controls the air-fuel vapor purge into intake manifold 12 based on engine operating conditions.

[0011] When the engine 10 is operated at partial load, ie the throttle valve 18 is between the idle position and the wide open throttle (position as element 18 in Fig. 1). The portion of the throttle body 14 upstream of the throttle valve 18 is subjected to manifold vacuum pressure. This vacuum involves airflow through tube 58, check valve 64, orifice 66, and port 68 into the throttle body 14. The purge flow is influenced by the relative position of the throttle valve 18 to port 68 and by the size of the orifice. The orifice 66 limits the purge airflow into the engine 10 as appropriate for proper operation.

[0012] When the engine 10 is operating under boosted conditions, the compressor 26 creates a higher pressure at the outlet 22 of the turbocharger 24 than at the inlet 36. Under these conditions, the compressor 26 creates positive pressure in the throttle body 14 and in the manifold 12. The check valves 62, 64 prevent airflow from the throttle body 14. The positive pressure at the outlet 22 causes air to flow through a tube 70 to an inlet end portion 72 of an ejector 74. The ejector 74 includes a housing defining the inlet end portion 72, the outlet end portion 66, and a reduced-dimension passage 78 (throat) therebetween. Air flows from the inlet 72 through the throat 78 to an outlet 76 and then through the tube 80 to the inlet 36 of the compressor 26. The air flow through the throat 78 reduces the pressure, as is well known to those skilled in the art.

[0013] The ejector 74 also includes a purge air passage 82 that opens into passage 78. The tube 54 is connected to the purge air passage of the ejector 74. A check valve 84 allows the flow of air and vapors from the tube 54 into the passage 82 and then into the passage 78. Ultimately, the air and vapor flow through the tube 70 into the throttle body 14 and then into the engine 10. During non-boosted operation of the engine 10, the check valve 84 prevents air flow from the ejector 74 back to the canister 38.

[0014] The emissions control described above operates effectively to direct purged vapors to the engine 10 and for treatment by a catalyst (not shown). However, under some conditions, it is not desirable to purge the canister 38. For example, when the catalyst is too cool to effectively process exhaust gases, provisions are made to prevent purging of the canister. A control valve 86 is provided downstream of the outlet opening 52 of the canister 38. The valve 86 has an outlet port 88 formed by a valve seat 90. A movable valve adjusting element, such as a diaphragm 92, is normally positioned against a seat 90 by a spring 94 so that air cannot flow through the valve 86. This is the condition of the valve when, as mentioned above, purging is not desired.

[0015] When airflow through valve 86 is desired, a vacuum pressure is created across diaphragm 92 into valve 86, unblocking port 88. The vacuum is delivered to valve 86 through a tube 96, which is connected to one port of an electromagnetically controlled on / off valve 98. Another port of valve 108 is connected to a tube 100. The tube is in turn connected to a tube 104. An electric solenoid valve 108 is connected to a tube 100. The tube 100 is in turn connected to check valve 102, which is connected to a tube 104. In the open state, the vacuum is transferred to the space above diaphragm 92, thus allowing purging. In the closed state, no vacuum is delivered to the space above diaphragm 92, thus allowing purging.When closed, no vacuum is released into the space above the diaphragm, and port 88 is blocked, preventing purging of the reservoir 38. The solenoid valve 108 is commanded to operate by an electronic control unit 110 (ECU) of the engine.

[0016] The Fig. 1 are provided merely as background to the present disclosure and are not intended to be limiting in any way. The components are known to be coupled in alternative ways, which are described in Fig. 1 are shown.

[0017] The ejector 74 after Fig. 1 has several deficiencies. It is a separate part that must be positioned, protected from damage, and stored separately. As is well known, an ejector is mounted on an engine intake component, such as in Fig. 4. First, Fig. 2, in which an ejector 120 is shown having a flange 122 through which the tubes 124 and 126 extend. The ejector 120 is shown in Fig. 3 in cross-section. An insert 130 with a reduced cross-section is arranged in the tube 124. The insert 130 has a throat 132 with a small cross-section. The velocity at which gases move through the throat 132 is much higher than the velocity of the flow at an inlet of the tube 124. Downstream of the insert 130 is a straight section 136. Preferably, this would be a diverging tube. Prior art manufacturing methods resulted in the tube 136 being straight. The tube 134 is coupled to the tube 124 at the location of the throat 132 via a T-tube 134 to thereby induce flow through 126.

[0018] During the manufacture of the ejector 120, the inner diameter of the tube 134 is formed by an orifice near a plug 128. After manufacture, the T-tube 134 is sealed by the plug 128. The ejector 120 is in Fig. 4 mounted on an air box 150.

[0019] The Fig. The ejector system shown in Figure 4 has some shortcomings. With reference to Fig. 4, the depth to which the ejector extends into the air box 150 is indicated by reference numeral 140, and the width of the ejector 120 within the air box 150 is indicated by reference numeral 142 in Fig. 3. This represents a significant intrusion into the interior of the air box 150. Air boxes have unique designs depending on the engine, the vehicle, and other packaging considerations such as other accessories. Although it would be desirable for a vehicle manufacturer to have three or four standard air boxes, there is actually little overlap between different vehicles. It is likely that many unique ejectors would be required to match the diverse air boxes. The significant intrusion may also result in a higher flow restriction for air flowing through the duct. The ejector according to the Fig. 2-4 includes three elements: the main body of the ejector 120, a cover 144, and an insert 130. The insert 130 is sometimes molded separately to avoid a molding process that uses a thin pin to form the orifice. A tube 136 downstream of the insert 130 is straight because a pin is drawn to form the tube 136. This is not the preferred shape, but simply what is available based on the manufacturing process. Disadvantages of the prior art include the following: the need to mold a separate piece for the insert and a plug; obtaining an ejector with lower flow characteristics than desired (due to a straight section downstream of the throat); and the resulting ejector being bulkier than desired.

[0020] Further prior art is known, for example, from DE 10 2016 005 468 A1, which shows an ejector for insertion into a receiving body, in which a tapered passage connects first and second feed openings. The insertion body is aligned by means of two grooves and locked into the receiving body by means of a locking lug.

[0021] Further ejector systems with insertable ejector pieces are shown in the documents DE 10 2005 002 264 A1, US 2015 / 0096541 A1 and US 5 005 550 A.

[0022] An ejector is desired that is compact and easy to manufacture while maintaining tight tolerances, especially in the throat area.

[0023] To avoid the aforementioned problem in the prior art, the present invention proposes an ejector according to claim 1, an ejector system according to claim 9, and an ejector system according to claim 15. Preferred embodiments of the invention are the subject of the dependent claims.

[0024] The ejector comprises a flange, a Venturi tube coupled to the flange, and a first and second tube extending through the flange. The first tube is fluidly coupled to one end of the Venturi tube. The second tube is fluidly coupled to a downstream end of a throat of the Venturi tube. The ejector comprises a first and a second piece that are coupled to each other. The first piece comprises the first and second tubes, the flange, and an upper half of the Venturi tube. The second piece comprises a lower half of the Venturi tube.

[0025] The flange is substantially flat and a centerline of the venturi tube is substantially parallel to the flange.

[0026] The second tube is substantially perpendicular to the flange, and a centerline of the first tube and a centerline of the second tube form an acute angle. Or, in other embodiments, a centerline of the first tube and a centerline of the second tube are substantially parallel; and the centerline of the first tube is substantially perpendicular to the flange.

[0027] The first piece and the second piece are coupled by means of sonic welding, vibration welding, induction welding, laser welding, ultrasonic welding, hot plate welding, and infrared or thermal welding. In other embodiments, the first and second pieces are coupled by a plurality of snap-fit ​​connectors disposed around the periphery of the first and second pieces. A seal between the first and second pieces is provided by one of: an adhesive material applied to the interfaces of the first and second pieces; and a groove in at least one of the interfaces with an O-ring disposed in the groove. In some embodiments, the seal is unnecessary.

[0028] The venturi tube comprises a converging section to which the first tube is fluidically coupled, the throat, and a diverging section. In some embodiments, the throat diverges.

[0029] In some embodiments, a centerline of the diverging section is angled slightly downward relative to the flange. In some embodiments, the diverging section has a round cross-section at the throat and a cross-section of a flattened circle at the exit, with the flattened portion of the circle being proximate to the flange.

[0030] Also disclosed is an ejector system comprising an ejector including a venturi tube having a converging section, a throat, and a diverging section; a first tube fluidly coupled to the converging section; and a second tube fluidly coupled to the throat. The venturi tube has a first and a second piece welded together.

[0031] An interface between the first and second pieces of the ejector essentially coincides with a diameter of the Venturi tube.

[0032] The first piece of the ejector includes the first and second tubes and a flange through which the first and second tubes pass.

[0033] The ejector system further includes an intake system component defining an opening and having a flat surface at the perimeter of the opening. A perimeter of the flange also has a flat surface. The flat surface of the flange is welded or otherwise attached to or integrated with the flat surface of the opening associated with the intake system component.

[0034] The intake system component is an air cleaning box or an air duct.

[0035] Burr traps are provided adjacent to the surface of the opening associated with the intake system component. Such burr traps largely prevent flowing material from reaching locations where it would interfere with the ejector's performance.

[0036] At least one burr trap is provided in the flange of the ejector immediately adjacent to the surface of the flange that is welded to the intake system component.

[0037] The first tube is further fluidically coupled to an air inlet and the second tube is further fluidically coupled to a volume associated with a fuel tank.

[0038] An ejector system for a turbocharged engine includes: an air duct and an ejector coupled to the air duct. The ejector comprises: a first piece including a first tube, a second tube, a flange with a flat surface around its circumference, and a first portion of a venturi tube; and a second piece coupled to the first piece and including a second portion of the venturi tube. The first and second pieces are attached by welding, snap-fit, and mechanical fasteners.

[0039] The air duct defines an opening with a flat surface surrounding the opening. The ejector flange has a flat surface that connects to the flat surface of the air duct. The flat surface of the ejector is welded to the flat surface of the air duct, with the ejector's venturi tube located within the air duct.

[0040] The ejector's venturi tube includes a converging section, a throat, and a diverging section. A centerline of the converging section and a centerline of the throat are substantially parallel to the flange. A centerline of the diverging section slopes downward from the plane of the flange, viewed in the direction of flow.

[0041] In one embodiment, an ejector for a canister purge system of a boosted engine includes: a flange; a venturi tube coupled to the flange, the venturi tube comprising a converging section, a throat, and a diverging section (alternatively referred to as a diffuser); a first tube fluidly coupled to the venturi tube upstream of the converging section; a second tube fluidly coupled immediately downstream of the throat; and an intake system component defining an opening and having a surface at the perimeter of the opening. A perimeter of the flange has a surface attached to the surface of the opening associated with the intake system component.

[0042] In some embodiments where the first and second pieces of the ejector are welded, one of the two pieces of the ejector has a rim extending from a periphery of the ejector. The rim forms a butt weld, and the mating surfaces form a butt weld. The rim serves as a guide for aligning the two pieces prior to welding.

[0043] The ejector is formed by one of: injection molding, 3D printing, casting, vacuum forming, blow molding, rotational molding, transfer molding, and machining a blank.

[0044] In some embodiments, a centerline of the diverging section is offset from a centerline of the converging section of the venturi tube. The offset may be in a vertically upward or downward direction.

[0045] The ejector is attached to the intake air component by one of the following: a weld, screws, mechanical fasteners, rivets, and an adhesive.

[0046] In some embodiments, the ejector is a single piece, such as in 3D printing. In other embodiments, the majority of the ejector is machined from a single piece with a plug in one end. The plug could be threaded or secured in some suitable manner. Such embodiments are suitable for conventional casting processes or machining a blank, as non-limiting examples.

[0047] In some ejectors, one of the tubes is beveled with respect to the flange; in some embodiments, both tubes are beveled with respect to the flange, i.e., a centerline of the tube forms an acute angle with the flange.

[0048] To prevent backflow under some operating conditions, it has been found helpful to provide a recess extending into the flow path of the diverging section of the ejector. In some embodiments, the recess is shaped like an elongated teardrop, and in other embodiments, it is rectangular. Other shapes are also within the scope of the disclosure.

[0049] By placing the venturi tube within the air system component, the ejector system is more protected from potential damage due to carelessness or in the event of an accident than if the ejector were primarily external.

[0050] The fact that the venturi tube extends substantially parallel to the flange of the ejector means that the ejector protrudes into the air system component to which it is attached to a far lesser extent than if the venturi tube were perpendicular to the flange as in the Fig. 2 and Fig. 3 presented state of the art.

[0051] Advantages of the disclosed embodiments include: simplified design, improved quality, fewer parts, lower unit costs, lower machining investments, fewer assembly steps, lower weight, and more reliable and repeatable manufacturing and assembly.

[0052] For applications where packaging is tight, the design in which one of the tubes is tapered relative to the other shortens the ejector length. If further shortening is desired, the flange near the exit of the diverging section is shortened. Both shortening designs can be combined to create a very compact injector.

[0053] The prior art method for manufacturing an ejector, as explained in more detail below, uses a pin to form the throat. In some applications, the pin used to form the throat of the venturi is so thin and long that it is highly likely to break, resulting in manufacturing downtime. The ejector disclosed here eliminates the need for such a pin entirely.

[0054] Another problem caused by the pin is flash, which is excess material moving where it's not intended. The converging and diverging sections of the venturi are quite large in diameter, and a few flashes won't cause significant blockage. They may disrupt flow somewhat and cause some flow loss. However, flash in the throat area is particularly troublesome, causing at the very least a variation in performance and likely failure. It could also become a source of contamination. This is a quality and scrap issue.

[0055] The ejector according to the embodiments disclosed herein provides a significant performance advantage of approximately 25% greater flow across the boost area compared to prior art ejectors. The reason for the flow advantage is that the two-piece division of the ejector by the venturi provides the ability to optimize the venturi geometry. This advantage also applies to single-piece ejectors, where the geometry is similarly controlled in a manner superior to prior art ejectors.

[0056] The invention is explained in more detail below using preferred embodiments and associated drawings: Fig. 1 is an illustration of a canister purge system incorporating an ejector according to the prior art; Fig. 2 is a state-of-the-art ejector; Fig. 3 is the ejector after Fig. 2 in cross section; Fig. 4 is the ejector after Fig. 2, shown installed in an air box; Fig. 5 is an ejector according to an embodiment of the disclosure; Fig. 6 is the ejector after Fig. 5 shown in cross section; Fig. 7 is a cross-sectional view of an ejector according to an embodiment of the disclosure; Fig. 8 is a cross-sectional view of an exit section of a venturi tube according to an embodiment of the disclosure; Fig. 9 is a graph of flow rate versus boost pressure comparing a prior art ejector and a presently disclosed ejector; Fig. 10 and Fig. 11 are cross-sections of a section of ejectors having snap connections; Fig. 12 is a flow diagram illustrating a prior art process by which an ejector may be manufactured; Fig. 13 is a flow diagram illustrating a process according to the present disclosure by which an ejector may be manufactured; Fig. 14 and Fig. 15 are flowcharts related to the Fig. 13 processes shown show alternative processes; Fig. 16 is a flowchart showing processes involved in installing the ejector in an engine air component; Fig. 17 is an illustration showing an air duct and an ejector before assembly; Fig. 18 is a cross-section of the air duct and ejector after assembly; Fig. 19 is a cross-sectional view of a shortened ejector; Fig. 20 is an illustration showing an air duct with the shortened ejector according to Fig. 19 shows before assembly; Fig. 21 is a one-piece embodiment of the ejector providing close tolerance for the diverging section, the converging section, and the throat; Fig. 22 is a two-piece embodiment of the ejector in which the centerline of the converging section is offset from the centerline of the diverging section; Fig. Figure 23 is an expanded cross-sectional view of a portion of the two pieces of the ejector showing an energy director and a rim; Fig. 24 is an isometric view of an ejector having a recess near the exit of the diverging section; Fig. 25 and Fig. 26 are two views of the diverging section of the ejector according to Fig. 24; and Fig. Figure 27 is an isometric view of an ejector having a rectangular shaped recess near the exit of the diverging section.

[0057] Those of ordinary skill in the art will appreciate that various features of the embodiments illustrated and described with respect to any of the figures may be combined with features illustrated in one or more other figures to produce alternative embodiments not expressly illustrated or described. The combinations of illustrated features provide representative embodiments for typical applications. However, various combinations and modifications of the features consistent with the teachings of the present disclosure may be desirable for particular applications or implementations. Those of ordinary skill in the art may recognize similar applications or implementations, whether or not expressly described or illustrated.

[0058] An embodiment of an ejector 150 according to the disclosure is shown in Fig. 5 and Fig. 6. The ejector 150 includes a flange 152 with a surface 154. The surface 154 enables coupling to the perimeter of an opening in an inlet component. The flange 152 includes a first tube 160 having a centerline 164 and a second tube 162 having a centerline 166 extending therethrough. The first tube 160 is coupled to an air inlet (not shown) for introducing fresh air. The second tube 162 is coupled to a carbon canister (also not shown) for purging the carbon canister. A venturi tube 170 is located at the bottom of the ejector 150. A first end 172 of the venturi tube 170 is closed and a second end 174 is open. The fresh air through the first tube 160 and the fuel vapor laden gases of the second tube 162, which are mixed in the venturi tube 170, flow out through the second end 174.The ejector 150 consists of two pieces welded together at interfaces between the two parts to form a weld 176. The weld 176 is slightly angled in the ejector 150. In other embodiments, the weld is flat. The first piece includes the elements above the weld 176, i.e., the first tube 160, the second tube 162, the flange 152, and an upper portion of the venturi tube 170. The second piece includes a lower portion of the venturi tube 170.

[0059] The weld 176 is substantially parallel to the flange 152 and coincides with a diameter of an opening through the venturi tube 170. Now Fig. 6, which is a cross-sectional view of Fig. 5 and shows an internal shape of the Venturi tube. An inlet section 180 receives fresh air from the tube 160. The purpose of the inlet section 180 is to rectify the flow after passing the 90-degree bend between the tube 160 and the inlet section 180. A converging section 182 is located downstream of the inlet section 180. The flow is accelerated in the converging section 182. The flow from the converging section 182 is directed into a throat 184. The throat 184 contains the section with the smallest cross-section of the Venturi tube 170. The Fig. 6, the throat 184 tapers slightly. The downstream end of the second tube 162 is coupled to the venturi tube 170 immediately downstream of the throat 184. As is well known to those skilled in the art, the acceleration of the flow in the throat results in a pressure drop that draws the flow through the tube 162. Downstream of the throat 184 is a taper section 186. In the embodiment in Fig. 6, a centerline of the diverging section 184 slopes downwards from left to right. This improves the flow characteristics. In other embodiments, the centerline of the venturi tube is straight. In some embodiments, as shown in Fig. 6, the tube 162 widens near a downstream end, such as shown by section 165 of the tube 162. In some embodiments, the welded joint between the two pieces of the ejector 150 is Fig. 6 shows a combination of a butt weld at the interface between the two surfaces and a shear weld. The shear weld is created by providing a rim 168 on the lower piece of the ejector 150 that extends toward the upper piece. In an alternative embodiment, the rim may be provided on the upper piece of the ejector 150.

[0060] With reference to Fig. Figure 7 illustrates an alternative embodiment of an ejector 200 that includes a flange 202 and first and second tubes 210 and 212 extending through the flange 202. The first tube 210 is tapered relative to the second tube 212. A centerline 220 of the first tube 210 forms an acute angle 230 relative to the flange 202. An advantage of such a design is that the tube 210 also serves as the inlet section of the venturi tube. A converging section 232 is directly coupled to the first tube 210. A throat 234 is located downstream of the converging section 232. A diverging section 226 is located downstream of the throat 234. The ejector 200 consists of two separately formed pieces that are attached to each other at a weld 226.Alternatively, these can be coupled by a snap connection, twist lock, mechanical fastening or with an adhesive.

[0061] One of the advantages of the Ejector 200 after Fig. 7 is that the length of the ejector 200 shown as 240 is compared to the length 190 of the ejector 150 according to Fig. 6 is shorter. Such a design requires a smaller opening in an air intake component to accommodate it. In an application where the intake duct has many curves and bends, there may only be a short section, just enough to accommodate the ejector. Thus, a shorter ejector is particularly useful in certain applications.

[0062] As explained below, the ejector 200 is coupled to an air intake component. In some embodiments, a surface 240 on the underside of the flange 202 interfaces with or mates with a surface of the intake air component. As explained, during the molding process, a portion of the material is displaced to an undesirable location, forming mold flash. When the ejector 200 is welded to the air intake component, weld flash develops. To prevent weld flash from moving to locations that would impair the function of the ejector, flash traps 242 and 244 are provided on both sides of the ejector 200.

[0063] An analysis of the design has shown that the exit cross-section of the ejector (e.g. 150, 200) is preferably a flattened circle. An exit 190 of an ejector is in Fig. 8. The upper section 192 of the outlet 190 is flattened. The outlet 190 consists of two pieces welded together at the interfaces 194.

[0064] The flow rate 850 of an ejector according to the state of the art and the flow rate 860 of the ejector according to Fig. 7 and Fig. 8 have been compared and in Fig. 9. The ejector according to the present disclosure exhibits significantly improved flow rate at all boost pressures. The improved flow rate is due to the Venturi tube having a separate converging and diverging section, rather than the straight tubes found in the prior art.

[0065] In an alternative embodiment, Fig. 10 illustrates an alternative method for attaching the upper piece 502 and lower piece 504 to a cross-section of a portion of an ejector 500. The lower piece 504 is provided with a groove 506 in a surface of the lower piece 504 that forms an interface with the lower piece 502. An O-ring 508 is placed in the groove 506. The upper piece 502 is provided with a recess 510 along an outer surface. The recess 510 does not extend completely to the interface with the lower piece 502. A lip 514 extends outwardly. The lower piece 512 is welded to a flexible finger 510 that engages the lip 514.

[0066] In another embodiment in Fig. 11, a cross-section of a portion of an ejector 520 includes an upper piece 522 and a lower piece 524. The upper piece 520 includes a wedge 530 extending outwardly from the surface. The lower piece 524 includes a flexible finger 532 that engages the wedge 530. In the embodiment shown in Fig. 11, an adhesive 526 has been applied to the interface of the upper part 522 and / or the interface of the lower part 524. In the explanation of the Fig. 10 and Fig. In Figure 11, the flexible finger is located at the lower part. However, this is merely a non-limiting example. Variations of these examples are also within the scope of the disclosure.

[0067] The improved design of the ejector disclosed here is based, at least in part, on a new process for manufacturing such ejectors. The prior art process is described in Fig. 12. In blocks 300 and 302, the resin to be fed to the injector molding machine meets the appropriate specification or is adequately dried. In block 304, the resin is injection-molded into the three molds to produce an ejector body, a plug, and an orifice piece that includes at least the throat of the venturi. The orifice piece is molded separately because the orifice size at the throat is small. It is possible to integrate the orifice piece into the ejector body. However, a thin pin is required to form the throat. A rule of thumb is that the length of the pin should be no more than 3.5 times the diameter of the pin. Such a pin for an integrated throat would exceed this safe dimension by at least an order of magnitude. Such a thin pin, capable of extending into the ejector body at such a distance, is likely to result in pin failures.This leads to breakage, downtime, increased scrap, and generally increases the cost of the manufacturing process. The more robust prior art manufacturing method is to manufacture the orifice piece separately. In block 306, the orifice piece is inserted into the ejector body. Each of the ejector bodies is inspected in block 308. If improperly installed, the part is rejected in block 310. If properly installed, the plug is attached to the ejector body in block 312. In the prior art ejector, as shown in FIG. Fig. 2 and Fig. 3, almost the entire ejector is formed in one piece. To move the tube 134 Fig. 3, an opening is provided at one end which is closed by the plug 144.

[0068] Quality control measures begin at block 350, where all leakage, flow, and vacuum generation are measured and determined to be within acceptable ranges. If so, the ejector is ready for assembly into an engine intake component at block 352. If the determination in block 350 is not as specified, block 360 determines whether the defect was caused by the molding process or flash (excess material on the part). If this is determined to be the problem, block 362 stops the molding process or performs machine maintenance and verifies that the correction is effective before proceeding. If block 360 is negative, block 370 determines whether the defect was caused by the welding process. If so, the welding operation or welding process is stopped at block 372. Block 372 also determines whether the correction is effective.If block 370 fails, block 380 determines whether the defect was caused by excessive moisture and / or whether the resin material is not within specification. If dryness is the cause of the defect, the material drying process is stopped and reviewed. If the material is not within specification, the appropriate material is retrieved and loaded into the molding machine in block 382. In any case, if a part does not meet specification, the part is rejected in block 392. If block 390 fails, additional process review continues until the cause of the defect is determined and corrected.

[0069] A flow chart showing processes undertaken to manufacture the disclosed ejector is shown in Fig. 13. Blocks 300, 302, 350, 352, etc., are largely the same for the disclosed process and the prior art process. Therefore, they will not be described separately here. Starting from block 320, the upper and lower pieces of the ejector are injection molded. In block 322, the two pieces are attached together. In one embodiment, the pieces are attached by welding: sonic, ultrasonic, thermal, or any suitable type of welding. An alternative embodiment is shown in Fig. 14, in which, in block 324, an O-ring is placed in a groove in an interface of the first or second piece. One of the first and second pieces has a flexible finger that engages a feature on the other piece in block 326. When the two pieces are snap-fitted together, the O-ring is pressed into the groove and seals the first piece to the second piece. In another alternative, in Fig. 15, the interfaces between the first and second pieces are flat. Adhesive is applied to at least one of the interfaces, block 328, so that the adhesive seals the interfaces between the first and second pieces when the first and second pieces are snap-fitted together in block 330.

[0070] In Fig. 16, an ejector is manufactured in block 400, such as by the process in the Fig. 13-16. In block 402, the air inlet component is manufactured with an opening to accommodate the ejector. In some embodiments, the ejector flange is as short as possible so that the opening in the inlet air component is as small as possible. This is particularly useful when the desired location is in an engine duct with numerous bends, i.e., a limited straight path to accommodate the ejector. In such cases with short ducts, in block 410, the exit section of the ejector is tilted downward to access the opening. In some other embodiments, the ejector can be inserted directly into the aperture without tilting. In block 412, the interface of the ejector flange is aligned with the interface of the air inlet component, i.e., a raised section around the opening in the air inlet component provided for this purpose.The ejector is welded to the intake air component in block 414.

[0071] In Fig. 17, an ejector 600 is shown over an air duct 610 prior to assembly. The ejector 600 includes a flange 602, first and second tubes 604 and 606, and a venturi tube 608. The air duct 610 includes a projection 618 that accommodates the formation of a flat surface 616 onto which a flange 602 is mounted. The surface 616 surrounds an opening 614 into which the venturi tube 608 is placed. The opening 614 is large enough to allow the venturi tube 608 to be inserted straight into the opening 614, as shown by arrows 630. The ejector 600 is attached to the air duct 610 by friction welding or any suitable process. A cross-section of an ejector-air duct assembly is shown in Fig. 18. The underside of the flange 602 is Fig. 17 on the circumference of the opening, surface 616.

[0072] The Fig. 17 and Fig. 18 has a straight section long enough to form an opening 614 (in Fig. 17) of the ejector 610. However, in some applications, air ducts have a limited ability to accommodate the ejector 610 or even the Fig. 7 shown shorter ejector. A shorter version of the ejector 150 according to Fig. 6 is in Fig. 19. The ejector 188 is almost identical to the ejector 150 according to Fig. 6, except that the flange 192 is positioned at the location 196 closer to the pipe 162 than in Fig. 6, is coupled to the diverging section 174. The length of the ejector 188 is shown such that it Fig. 19 has a length of 198, which is shorter than the ejector 150 according to Fig. 6, which has a length of 190.

[0073] In Fig. 20, a shortened ejector 640 is shown having a shortened flange 642 (similar to the shortened flange in Fig. 19), wherein the tubes 604 and 606 extend from the flange 642. The air duct 650 has a projection 658 having an opening 654 (also foreshortened) having a surrounding surface 656 to which a flange 642 is attached. Since the venturi tube 608 is shorter than the venturi tube 608 with respect to the flange 602 according to Fig. 17 protrudes beyond the flange 642, the Venturi tube 608 cannot be installed directly in the opening 654, but must be installed as shown in Fig. 20. After the venturi tube 608 is inserted into the opening 654, the ejector 640 can be straightened so that the flange 642 meets the surface 656. This tilting and subsequent straightening is illustrated by the arrow 660.

[0074] The manufacture of ejectors by injection molding is known. In the prior art, such a manufacturing technique results in the difficulty of manufacturing diverging and converging sections in the ejector, since such sections are formed by cylindrical pins. According to the embodiments disclosed above, the two-piece version split along the venturi tube allows for the formation of a complex shape with a converging section, a diverging section, and a throat that, in some embodiments, diverges slightly. In the prior art, throats are typically straight. However, in some applications, the diverging throat has been found to result in improved flow efficiency, approaching supersonic flow.In some embodiments, the diverging section has a non-uniform shape, and in some embodiments, it is tilted downward; such features are easily achieved with the two-piece ejector disclosed herein. Although it may be less costly to injection mold the ejector in two pieces, there are alternative manufacturing techniques that allow the desired shape to be formed in one piece. A 3D printing process is one alternative. The result could resemble any of the . Fig. 5-7, except that the ejector would be one piece. The difference between a 3D printed ejector according to an embodiment of the present disclosure compared to the prior art in the Fig. 2-4 is that the ejector in the Fig. 2-4 has a straight tube, whereas a 3D-printed ejector can have a converging section, a throat with a controlled diameter, and a diverging section. In yet another, in Fig. In the embodiment shown in Figure 21, an ejector according to one embodiment of the disclosure is formed in one piece by a traditional casting process. To remove the core pieces, i.e., those that provide the openings within the venturi tube, a plug is provided near the upstream end of the venturi tube. Finally, although very costly, the ejector can be machined from a blank.

[0075] In Fig. 22, an ejector 710 has a throat 715 with a converging section on the left (upstream) and a diverging section on the right (downstream). A centerline 712 of the converging section is offset from a centerline 714 of the diverging section. A left tube 716 of the ejector 710 is beveled. A right tube 718 is also beveled in the ejector 710. It has been found through modeling that such an offset provides greater flow, particularly when both tubes 716 and 718 are beveled, as in Fig. 22 shown.

[0076] As described above, some embodiments feature a snap-fit ​​connection to secure the two pieces of the ejector together. In such embodiments, an O-ring, adhesive, or other sealing means may be used. Alternatively, an unevenness near the periphery of one of the pieces will cause it to collide with the other piece of the ejector, as shown in Fig. 23. An ejector 720 includes a first piece 722 and a second piece 724. The second piece 724 includes flexible fingers 730 and 732 for snapping around projections 740 and 742, respectively. Fig. 3 is for illustrative purposes only to show two possibilities by which the ejector pieces 722 and 724 can be sealed. On the left side of Fig. 23, a rib 750 extends outwardly from the projection 740. The rib 750 causes a collision with an inner wall of the flexible finger 730. On the right side of Fig. Figure 23 illustrates an alternative seal in which a rib 752 extends from the protrusion 742 to the second piece 724. The rib 752 causes collision with a top surface of the second piece 724 near the protrusion 742.

[0077] As described above, some embodiments feature a snap-fit ​​connection to secure the two pieces of the ejector together. In such embodiments, an O-ring, adhesive, or other sealing means may be used. Alternatively, an unevenness near the periphery of one of the pieces will result in interference with the other piece of the ejector.

[0078] In Fig. Figure 23 shows a detail of a lower portion 900 of the ejector. A surface 902 includes an energy director 904 useful in the welding process. The energy director 904 typically protrudes about 0.6 mm from the surface. The surface 902 forms a butt weld with respect to a mating surface (not shown). A rim 908 serves two functions: It serves as a guide for locating the mating surface during assembly. In addition, the surface 908 forms a shear weld with a portion of the mating part.

[0079] An isometric view of an ejector has a diverging section 1000 in which a recess 1002 is formed, as in Fig. 24 shown. Fig. 25 is a plan view of the diverging section 1000 with the recess 1002 and Fig. 26 is a side view. Fig.Figure 27 shows an isometric view of an ejector 1100 in which a diverging section 1002 is provided with a rectangular-shaped recess 1106 having a short wall 1104. The recesses 1002 and 1106 are provided to prevent backflow, which would reduce flow through the ejector, which occurs under some operating conditions.

Claims

[1] Compact ejector for a canister purge system of a turbocharged engine (10), comprising: a flange (152); a venturi tube (170) coupled to the flange (152); and a first and a second tube (160; 162) extending through the flange (152), wherein: the first tube (160) is fluidly coupled to one end of the Venturi tube (170); the second tube (162) is fluidly coupled to a downstream end of a throat (184) of the venturi tube (170); the ejector comprises a first and a second piece coupled together; the venturi tube (170) comprises a first and a second piece coupled together; the first piece comprises the first and second tubes (160; 162), the flange (152) and an upper portion of the venturi tube (170); and the second piece comprises a lower section of the Venturi tube (170). [2] The ejector of claim 1, wherein the flange (152) is substantially planar and a centerline of the venturi tube (170) is substantially parallel to the flange (152). [3] Ejector according to claim 1, wherein: the second tube (162) is substantially perpendicular to the flange (152); and a center line of the first tube (160) and a center line of the second tube (162) form an acute angle. [4] Ejector according to claim 1, wherein: a centerline of the first tube (160) and a centerline of the second tube (162) are substantially parallel; and the center line of the first tube (160) is substantially perpendicular to the flange (152). [5] The ejector according to claim 1, wherein the first piece and the second piece are coupled by one of sonic welding, ultrasonic welding, heat welding, vibration welding, induction welding, laser welding, a heating element, and infrared welding. [6] Ejector according to claim 1, wherein: the first and second pieces are coupled by a plurality of snap connectors arranged around the circumference of the first and second pieces. [7] Ejector according to claim 1, wherein: the Venturi tube (170) comprises a converging section (182) to which the first tube (160) is fluidically coupled, the throat (184) and a diverging section (186). [8] Ejector according to claim 7, wherein at least one of the following properties of the diverging section (186) is present: a center line of the diverging section (186) is angled slightly downward with respect to the flange (152); and the diverging section (186) has a round cross-section near the throat (184) and a cross-section of a flattened circle near an exit of the diverging section (186). [9] Ejector system for a supercharged engine (10), comprising: an air system component; an ejector coupled to the air system component, the ejector comprising: a first piece comprising a first tube (160), a second tube (162), a flange (152) having a surface around the circumference and a first portion of a venturi tube (170); and a second piece coupled to the first piece and comprising a second portion of the venturi tube (170). [10] The ejector system of claim 9, wherein the first and second pieces are secured by one of welding, snap fit, and mechanical fasteners. [11] Ejector system according to claim 9, wherein: the air system component defines an opening with a surface surrounding the opening; the flange (152) of the ejector (150; 200; 500; 520; 600; 640; 710; 720) has a surface that connects to the surface of the air system component; and the surface of the ejector (150; 200; 500; 520; 600; 640; 710; 720) is welded to the surface of the air system component, wherein the Venturi tube (170) of the ejector (150; 200; 500; 520; 600; 640; 710; 720) is located within the air duct. [12] Ejector system according to claim 9, wherein: the venturi tube (170) of the ejector comprises a converging section (182), a throat (184) and a diverging section (186); a centerline of the converging portion (182) and a centerline of the throat (184) are substantially parallel to the flange (152); and a center line of the diverging section (186) slopes downwards from the plane of the flange (152), viewed in the direction of flow. [13] The ejector system of claim 9, wherein the air system component is one of an air filter box (150) and an inlet air duct (650). [14] The ejector system of claim 9, wherein, when the first piece is coupled to the second piece, a seal between the first and second pieces (520; 524) is provided by one of: an adhesive material (526) applied to the interfaces of the first and second pieces (520; 524); and a groove in at least one of the interfaces with an O-ring arranged in the groove. [15] Ejector system for a canister purge system of a supercharged engine (10), comprising: a flange (152); a venturi tube coupled to the flange (152), the venturi tube (170) comprising a converging section (182), a throat (184) and a diverging section (186); a first tube (160) fluidly coupled to the venturi tube (170) upstream of the converging section (182); a second tube (162) fluidly coupled to the venturi tube (170) immediately downstream of the throat (184); and an intake system component defining an opening and having a surface at the perimeter of the opening, wherein: a periphery of the flange (152) has a surface; and the surface of the flange (152) is secured to the surface of the opening associated with the intake system component. [16] Ejector system according to claim 15, wherein: the ejector consists of two pieces coupled by a welded joint and a snap-in joint; the first piece comprises the first tube (160), the second tube (162), the flange (152) and a first portion of the venturi tube (170); and the second piece comprises a second section of the Venturi tube (170). [17] The ejector system of claim 16, wherein one of the two pieces of the ejector has a rim extending from a periphery of the ejector to thereby provide a butt and shear weld and orientation for assembly. [18] Ejector system according to claim 15, wherein the ejector is formed by one of: Injection molding, 3D printing, casting, vacuum forming, blow molding, rotational molding, resin transfer molding, and machining a blank. [19] The ejector system of claim 15, wherein a centerline of the diverging portion (186) is offset from a centerline of the converging portion (182) of the venturi tube (170). [20] Ejector system according to claim 15, wherein: the intake air component is one of an intake air duct (650) and an air filter box (150); the ejector is attached to the intake air component by at least one of the following: a weld, screws, mechanical fasteners, rivets, and an adhesive. [21] Ejector system according to claim 15, wherein at least one of the following applies: a center line of the first tube (160) forms an acute angle with the plane of the flange (152); and a center line of the second tube (162) forms an acute angle with the plane of the flange (152). [22] The ejector system of claim 15, wherein a recess extends into the flow path of the diverging section (186) near the outlet end of the diverging section (186).

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