FLUSHING VALVE WITH STEAM RECOVERY SYSTEM AND METHOD

Abstract

Canister flushing valve (112), comprising: an inlet opening (212) configured to couple with an inlet line for receiving a fluid from a steam recovery canister (22); and an outlet (214) with two or more outlet openings (216) configured for coupling with a common outlet line (218) for directing fluid to a motor (8); characterized in that, that the two or more outlet openings (216) at the outlet (214) are arranged in a Gaussian distribution around a predetermined location at the outlet (214), wherein the distance of each outlet opening (216) from a preselected center of the distribution, when represented on a curve as a function of the number of outlet openings (216) at the corresponding distance, approximates a Gaussian distribution.

Description

[0001] The present application relates to a system and method for recovering fuel vapor in an engine system, and more particularly to a system and purge valve having a single inlet and two or more outlet orifices configured to flow into a common outlet conduit.

[0002] Vapor recovery systems are used in engines to capture fuel vapors and thereby reduce vapor emissions. Fuel vapor recovery canisters, which generally contain vapor-absorbing carbon, can be used to capture and store fuel vapor at various times, such as during refueling. Fuel vapors can then be purged from the canister while the engine is running and combusted by forcing atmospheric air through the canister and into the engine combustion chamber. The air used to purge the canister is controlled by a canister purge valve.

[0003] DE 11 2004 000 114 B4 discloses a solenoid valve having a housing consisting of two split bodies, wherein one of the split bodies has an electromagnetic coil and a fixed and a movable iron core and the other split body has an inlet opening and an outlet opening.

[0004] A valve for reducing pressure in a compressible fluid is known, for example, from US 6 505 646 B1.

[0005] DE 11 2006 001 897 T5 discloses a system for processing vaporized fuel gas, which receives vaporized gas in a fuel tank and comprises an outlet port, an inlet port, and an electromagnetic valve device. The gas is temporarily adsorbed in a canister and supplied to an engine intake system. One of the existing problems with canister purge valves is that they can be noisy. An attempt to reduce canister purge valve noise is described in US patent US 6,739,573 B1 to Balsdon. The disclosure attempts to dampen or mitigate the undesirable noise generated due to the opening and closing of the valve by providing a shock-absorbing elastic element to absorb, dampen, or attenuate the impact of the valve on a valve seat.

[0006] The inventors of the present application have identified a problem with the above solution. In particular, the disclosed approach fails to address the primary cause of canister purge valve noise. Current canister purge valves generate undesirable airflow noise during operation. Research and test data have shown that the airflow noise occurs when the valve opens or closes. The cause of the airflow noise is the abrupt change in air pressure between the valve inlet and outlet when the valves transition between open and closed. The sound wave travels from the valve outlet into the engine intake manifold.

[0007] The inventors herein have discovered a way to interrupt the sound wave on its way to the intake manifold. Embodiments according to the present disclosure provide a valve outlet design that can prevent the sound wave from directly entering the intake manifold. These embodiments can be used to break the exhaust flow and the associated sound wave into smaller, respectively. In this way, the sound wave intensity can be significantly reduced.

[0008] According to the invention, the above-mentioned problems are solved according to claim 1. Preferred embodiments are the subject of the subclaims.

[0009] In another example, some of the above problems are addressed by providing a fuel vapor recovery system for an engine. The system may include: a vapor recovery canister disposed in fluid communication with a fuel tank; an intake manifold in fluid communication with an engine combustion chamber; and a purge valve configured to control fluid flow, the purge valve having an inlet coupled to the fuel tank and an outlet pipe having two or more outlet openings coupled in a single, common outlet conduit leading to the intake manifold. In yet another example, some of the above problems may be addressed by providing a method of operating an engine vapor recovery system.The method may include directing a purge gas from a canister through a valve to an engine intake manifold; wherein the purge gas may exit from the valve into a single purge line through two or more outlet ports.

[0010] They show: Fig. 1 is a schematic representation of an engine system having an example fuel vapor recovery system according to the present disclosure; Fig. 2 is a front view illustrating an example of a purge valve according to the present invention which is used with the fuel vapor recovery system of Fig. 1 can be used; Fig. 3 is a partial cross-sectional view illustrating alternative downstream details of another example purge valve according to the present disclosure; Fig. 4 is a partial cross-sectional view illustrating another example flush valve according to the present disclosure; Fig. 5 is a flowchart illustrating an example method for operating the fuel vapor recovery system according to the present disclosure; Fig. 6 is a flowchart showing an example modification of the method of Fig. 5 represents; Fig. 7 is a flowchart showing an example modification of the method of Fig. 6 represents; Fig. 8 is a flowchart showing another example modification of the method of Fig. 6 represents; Fig. Figures 2 to 4 are drawn approximately to scale, although other relative dimensions may be used upon request.

[0011] Fig. 1 is a schematic representation of a vehicle system 6. The vehicle system 6 includes an engine system 8 coupled to a fuel vapor recovery system 200 and a fuel system 18. The engine system 8 may include an engine 10 having a plurality of cylinders with corresponding plurality of combustion chambers 30. The engine 10 includes an engine mount 23 and an engine exhaust 25. The engine mount 23 includes a throttle body 62 in fluid communication with the engine intake manifold 44 via an intake passage 42. The engine exhaust 25 includes an exhaust manifold 48 leading to an exhaust passage 35 that discharges exhaust gas to the atmosphere. The engine exhaust 25 may include one or more emission control devices 70, which may be mounted in a tightly coupled position in the exhaust. One or more emission control devices may include a three-way catalyst, lean NOx trap, diesel particulate filter, oxidation catalyst, etc.It will be appreciated that other components may be incorporated into the engine, such as various valves and sensors, which are further described in the example embodiments of . Fig. 2 to 6 are worked out.

[0012] The engine mount 23 may further include an augmentation device, such as a compressor 74. The compressor 74 may draw in intake air at atmospheric pressure and pressurize it to a higher pressure. The augmentation device itself may be a compressor of a turbocharger, with the amplified air being introduced into a pre-throttle valve, or the compressor of a supercharger, with the throttle valve located upstream of the augmentation device. By using amplified intake air, amplified engine operation can be achieved.

[0013] The fuel system 18 may include a fuel tank 20 connected to a fuel pump system 21. The fuel pump system 21 may include one or more pumps for pressurizing fuel delivered to the injectors of the engine 10, such as the illustrated injector 66. Although only a single injector 66 is illustrated, additional injectors may be provided for each cylinder. It will be appreciated that the fuel system 18 may be a less return fuel system, a recirculation fuel system, or one of various types of fuel systems. Vapors generated in the fuel system 18 may be routed via the conduit 31 to a fuel vapor recovery system 200, as described below, before being purged into the engine mount 23. The conduit 31 may optionally include a fuel tank isolation valve.Among other things, the fuel tank isolation valve may accommodate a fuel vapor canister 22 of the fuel vapor recovery system 200 under low pressure or vacuum without increasing the fuel vaporization rate from the tank (which would otherwise occur if the fuel tank pressure were reduced). The fuel tank 20 may hold multiple fuel mixtures, including fuel with a range of alcohol concentrations, such as various gasoline-ethanol blends, including E10, E85, gasoline, etc., as well as combinations thereof. A fuel tank pressure transducer (FTPT) 120 or fuel tank pressure sensor may be disposed between the fuel tank 20 and the fuel vapor canister 22 to provide an estimation of fuel tank pressure and leak detection when the engine is off.The fuel tank pressure transducer may be alternately located in pipe 31, purge line 28, vent 27, or fuel vapor canister 22 without losing its engine-off leak detection capability.

[0014] The fuel vapor recovery system 200 may include one or more fuel vapor recovery devices, such as one or more fuel vapor canisters 22 filled with an appropriate adsorbent, where the canisters 22 may be configured to temporarily contain fuel vapors (including vaporous hydrocarbons) during fuel tank filling and "run-out" (i.e., fuel vaporized during vehicle operation). In one example, the adsorbent used may be activated carbon. The fuel vapor recovery system 200 may further include a vent 27 that can release gas from the recovery system 200 to the atmosphere when storing or capturing fuel vapors from the fuel system 18.The vent 27 may also allow fresh air to be drawn into the fuel vapor canister 22 when the stored fuel vapors are purged from the fuel system 18 to the engine intake 23 via the purge line 28 and the purge valve 112. A canister check valve 116 may be included in the purge line 28 to prevent (amplified) intake manifold pressure from the flowing gases from passing in the opposite direction into the purge line. Although this example shows the vent 27 exchanging fresh, unheated air, various modifications may also be used. The flow of air and vapors between the fuel vapor recovery system 22 and the atmosphere may be regulated by operation of the canister vent solenoid (not shown) connected to the canister vent valve 108.Further details regarding the fuel vapor recovery system 200, particularly details regarding the purge valve 112, are described below with respect to FIG. Fig. 2 and Fig. 3 described.

[0015] The vehicle system 6 may further include the control system 14. The control system 14 receives information from a plurality of sensors 16 (various examples of which are described herein) and sends control signals to a plurality of actuators 81 (various examples of which are described herein). As one example, the sensors 16 may include the exhaust gas sensor 126 located upstream of the emissions control device, the temperature sensor 128, and the pressure sensor 129. Other sensors, such as pressure, temperature, air / fuel ratio, and composition sensors, may be connected to various locations in the vehicle system 6, as described in more detail herein. As another example, the actuators may include the fuel injector 66, the valve 29, and the throttle 62. The control system 14 may include a controller 12.The controller may receive input data from the various sensors, process the input data, and trigger the actuators in response to the processed input data based on the instruction or code programmed therein according to one or more routines. Example control routines are described herein with respect to . Fig. 4 to 7.

[0016] The fuel vapor recovery system 200 may store vaporized hydrocarbons (HC) from the fuel system 18. Under some operating conditions, such as during filling, the fuel vapors present in the fuel tank may be displaced when liquid is added to the tank. The displaced air and / or fuel vapors may be routed from the fuel tank 20 to the fuel vapor canister 22 and then vented to the atmosphere through the vent 27. In this way, a higher amount of vaporized HC may be stored in the fuel vapor canister 22. During later engine operation, the stored vapors may be added back to the incoming air load using intake manifold vacuum. In particular, the fuel vapor recovery system 22 may draw fresh air through the vent 27 and draw stored HC into the engine intake for combustion in the engine.This purge operation may occur during selected engine operating conditions as described herein.

[0017] The fuel vapor recovery system 200 may include one or more fuel vapor containment devices, such as one or more fuel vapor canisters 22. The canister 22 may be filled with an adsorbent capable of capturing large amounts of vaporized HC. In one example, the adsorbent used is activated carbon. The canister 22 may receive fuel vapors from the fuel tank 20 through the conduit 31. While the illustrated example shows a single canister, it will be appreciated that in alternative embodiments, multiple such canisters may be interconnected.

[0018] A tank isolation valve (not shown) may optionally be disposed in conduit 31 to temporarily prevent fuel vapor pressure from transmitting itself to the rest of the fuel vapor control system. In one example, the tank isolation valve may be mounted to the fuel tank. In another example, as illustrated herein, the tank isolation valve may be connected to the fuel tank along conduit 31. Thus, the optional tank isolation valve 205 may prevent vapor from flowing to the fuel vapor canister 202, thereby reducing fuel vaporization in the tank. Therefore, in the absence of the tank isolation valve, the fuel tank 20 may be subject to low intake manifold pressures, which may accelerate vapor generation. Additionally, canister purge may be most effective when the tank is isolated from the canister.

[0019] Still in relation to Fig. 1, an example embodiment of a fuel vapor recovery system 200 for an engine 8 is shown, and Fig. 2, which illustrates details of a purge valve 112 that the system 200 may include. The fuel recovery system 200 may include a vapor recovery canister 22 in fluid communication with a fuel tank 20. The fuel recovery system 200 may also include an intake manifold 23 in fluid communication with an engine combustion chamber 30. A purge valve 112 may be configured to control a flow of fluid, indicated by arrows 210 in Fig. 2. The purge valve 112 may have an inlet 212 connected to the fuel tank 20. The system 200 may also have an outlet pipe 214 with two or more outlet openings 216 coupled together in a single, common drain line 218 ( Fig. 2), which leads to the intake manifold 23.

[0020] Fig. 3 is a partial cross-sectional view with alternative downstream details of another example purge valve 112 according to the present disclosure. The purge valve 112 may be the canister purge valve 112, which may be configured with an inlet opening ( Fig. 1 and Fig. 2) and with an inlet line for receiving a fluid from a steam recovery canister 22 ( Fig. 1). The canister purge valve 112 may include an outlet 214 with two or more outlet openings 216, which may be configured for connection to a common outlet line 218 to direct the fluid to an engine 8. The common outlet line 218 may lead to the intake manifold 23 of the engine 8. Example fluids may be gases and vapors, for example, originating from the gas tank 20.

[0021] In some embodiments, the two or more outlet openings 216 may be three or four or more outlet openings, where the canister purge valve may be a valve of an engine fuel recovery system. The outlet openings 216 may be arranged radially on the outlet. In some cases, the outlet openings may be substantially equally spaced. For example, three outlet openings may be arranged at substantially 120 degrees apart; four outlet openings may be arranged at substantially 90-degree increments; five at 72-degree increments, etc. The bottom of the outlet tube 214 may, for example, be sealed with an end wall 244 so that the only outlet openings are on the cylindrical sides of the outlet tube 214.

[0022] The outlet openings 216 are arranged in a preselected distribution determined by a mathematical function equation. Specifically, the outlet openings 216 are arranged in a Gaussian distribution. For example, an outlet tube 214 may have nine holes evenly spaced around a circumference of the outlet tube 214, but the distance of each outlet opening from a preselected distribution center, when represented by a curve, approximates a Gaussian distribution.

[0023] Alternative distributions not according to the invention can be applied in a similar manner.

[0024] In some embodiments, the outlet openings may be randomly arranged on the outlet tube 214. The distance of each outlet opening 216 from a predetermined location may be randomly determined, for example, by using a random number generator and the like. The random Distribution or other distribution patterns may be applied to the circumferential or longitudinal location of the exit openings on the outlet tube 214.

[0025] Some embodiments may be configured to at least partially cancel the sound that may be generated by the valve 112 through a predetermined dimension and shape of the outlet tube 214. For example, the sound may reflect off the end wall 244 and back toward the incoming or downstream-moving sound wave. The reflected sound wave may interfere with the incoming wave, such that destructive interference may occur. Additionally, or alternatively, in some embodiments, the exit ports may be located in regions of minimal sound intensity. In this way, the most intense portions of the sound waves may be attenuated within the valve, so that only the least intense components of sound exit the valve through the exit ports.Some embodiments may be configured such that various parts of the valve, and the valve as a whole, are constructed to rupture and / or prevent a particular structural resonance of the valve, the valve components, and / or the fluid flowing through the valve. For example, the valve and parts of the valve may be constructed to be largely rigid or largely elastic, such that the valve and valve parts have a natural vibration frequency that is sufficiently different from substantially any vibration frequency that may be caused by the valve actuation or the fluid flowing through the valve. The "fine-tuning" of the natural frequency may be achieved, at least in part, by the size and / or placement and / or number of exit ports in the valve. In some embodiments, the outlet tube 214 may be substantially cylindrical in shape.In other embodiments, the outlet tube may have a different shape. The two or more outlets 216 may exit from a cylindrical surface 220 of the substantially cylindrical outlet tube 214.

[0026] The valve 112 of the fuel recovery system 200 may include a circumferential seal 224 that may be configured to contact an inner surface 230 of the outlet conduit 218 upstream of the outlet exit ports 216. A clearance 232 may be defined between the inner surface 230 and a portion of the valve downstream of the seal 224. The seal 224 may be a gasket 224 that may be located upstream of the two or more exit ports 216. The seal may be in contact with the inner wall 230 of the outlet conduit 218. The seal 224 may be an O-ring 224 that sits in an O-ring seat 222 formed on the outlet tube and located upstream of the two or more outlet openings 216 configured to receive an O-ring 224 to provide a sealing engagement 226 between the outlet conduit 218 and the valve 112.The outer diameter of the O-ring 224 may be sufficiently larger than an outer diameter of the outlet tube 214 to provide the clearance 232 so that the flow of steam can flow from the outlet openings 216, past the end of the valve, and into the common outlet conduit 218.

[0027] Fig. 3 also shows an example embodiment wherein the outlet tube 214 may have a substantially centrally located bore 240 in fluid communication with the inlet port 212. The bore 240 may be closed at a downstream end 242. The bore 240 may be closed by an end wall 244. The two or more exit ports 216 may be in fluid communication with the bore 240. The bore 240 may fluidly connect the inlet port 212 to the exit ports 216. As shown, a first exit port may be offset in a flow direction along the bore compared to a second exit port. In some examples, each exit port is offset in the flow direction from every other exit port.In other examples, a first pair of exit ports is located at the same downstream location but offset downstream from a second pair of exit ports located at the same downstream location. Further, the first pair of exit ports may be located on opposite sides of the cylindrical surface 220, as may the second pair of exit ports, with the first and second pairs of exit ports being approximately 90 degrees apart from each other about the axis 250. In another example, some exit ports may be located closer to the seal 224 than other exit ports. Further, some exit ports may be located closer to the closed end 244 than other exit ports.Still further, a diameter of the bore upstream of the farthest exit opening can be varied compared to that downstream of the farthest exit opening, such that the bore has a smaller diameter in the downstream region compared to the upstream region to provide a more uniform flow rate distribution within the exit openings. In some examples, there are no exit openings upstream of the seal 224. Furthermore, in some cases, the bore 240 can be offset within the outlet tube 214.

[0028] As particularly in Fig. 3, in some embodiments, at least one exit opening may be longitudinally offset from at least one other exit opening. The illustrated example shows first two exit openings 216 exiting to the right and left of a central axis 250, as viewed on the side, and second two exit openings 216 exiting in and out of the side above the first two exit openings 216. In some examples, every other one of the four outlet openings 216 may be arranged longitudinally offset from the other. In some examples, every other one of the four exit openings may be longitudinally offset with respect to the nearest exit opening 216. In some cases, all may be arranged at the same longitudinal position of the outlet tube. In some cases, these may be offset in various ways.

[0029] Fig. 4 is a partial cross-sectional view illustrating another example purge valve 112 according to the present disclosure. The purge valve 112 may include a central bore 240 that may have a first portion 410 with a variable inner diameter extending in the downstream direction and opening into a wider second portion 412. The second portion 412 may lead into a relatively large cavity 414 defined by a relatively thin tubular housing 416. An incoming sound wave 418 is represented by a series of arcs traveling downstream. A reflected sound wave 420 is represented by a series of arcs traveling upstream. Relatively smaller outgoing sound waves 422 are represented by a series of relatively smaller arcs exiting the exit ports 216 to represent relatively low intensity sound.

[0030] In various embodiments, the two or more exit ports 216 may exit the valve 112 in directions substantially perpendicular to the central axis 250 of the valve 112. In other cases, the exit ports 216 may exit the valve 112 in different directions. In some cases, one or more ports may exit the valve 112 in directions substantially perpendicular to a central axis 240 of the valve 112, with every other one or more exit ports 216 exiting the valve 112 in directions that are not perpendicular to a central axis 240.

[0031] An embodiment may provide a fuel vapor recovery system 200 in which the outlet tube 214 may be substantially cylindrical. The two or more outlet openings 216 may be four outlet openings 216 radially exiting from the cylindrical surface 220 of the outlet tube 214. The four outlet openings 216 may be arranged in approximately 90-degree increments on the cylindrical wall 220, and two of the four outlet openings 216 may be longitudinally offset from the other two of the four outlet openings 216.

[0032] Fig. 5 is a flowchart illustrating an example method for operating an engine vapor recovery system 500. The method 500 may include, at 502, directing a purge gas from a canister through a valve to an engine intake manifold; wherein the purge gas exits the valve from two or more outlet openings in a single purge line. The single purge line may lead to an intake manifold. The two or more outlet openings may direct the purge gas from the valve in two or more directions that are each different from one another. The two or more directions may include directions that are radially arranged differently from a central axis of the valve.

[0033] Fig. 6 is a flowchart illustrating an example modification of the method 500 of Fig. 5. The method 500 may be modified in that directing the purge gas from the canister through the valve 502 at 604 may include directing purge gas to exit in four directions that are substantially perpendicular to each other.

[0034] Fig. 7 is a flowchart illustrating an example modification of the method 600 of Fig. 6. The method 600 may be modified in that directing the purge gas in the four directions 604 at 706 may include directing the purge gas in four directions that are offset in longitudinal positions along the intake manifold side of the valve.

[0035] Fig. 8 is a flowchart illustrating an example modification of the method 600 of Fig.6. The method 600 may be modified in that directing the purge gas in the four directions 604 at 808 may include directing purge gas from locations located downstream of a seal that seals the purge line to the valve.

Claims

[1] Canister flush valve (112), comprising: an inlet opening (212) configured to couple to an inlet conduit for receiving a fluid from a vapor recovery canister (22); and an outlet (214) having two or more outlet openings (216) configured to couple to a common outlet conduit (218) for conducting fluid to a motor (8); characterized by , that the two or more outlet openings (216) at the outlet (214) are arranged in a Gaussian distribution around a predetermined location on the outlet (214), wherein the distance of each outlet opening (216) from a preselected center of the distribution, when plotted on a curve as a function of the number of outlet openings (216) at the corresponding distance, approximates a Gaussian distribution. [2] Canister purge valve (112) according to claim 1, wherein the two or more outlet openings (216) are four outlet openings, the canister purge valve (112) being a valve of a fuel recovery system of the engine (8). [3] Canister purge valve (112) according to claim 2, wherein the four outlet openings (216) are arranged radially on the outlet (214), and wherein the four outlet openings (216) are arranged to be coupled to the common outlet line (218) leading to an intake manifold (23) of the engine (8). [4] Canister purge valve (112) according to claim 1, wherein at least one outlet opening (216) is longitudinally offset from at least one other outlet opening (216). [5] The canister purge valve (112) of claim 1, further comprising an outlet tube (214) on a downstream side of the valve having a substantially centrally located bore (240) in fluid communication with the inlet port (212), the bore (240) being closed at a downstream end (242) thereof, and the two or more outlet ports (216) being in fluid communication with the bore (240). [6] Canister purge valve (112) according to claim 1, wherein the two or more outlet openings (216) are arranged randomly at the outlet (214). [7] The canister purge valve (112) of claim 1, further comprising a cavity (414) configured such that at least a portion of a downstream moving acoustic wave (418) experiences destructive interference with an acoustic wave (420) reflected from an end wall (244). [8] The canister purge valve (112) of claim 1, wherein the valve and portions of the valve are constructed to break up and / or prevent a particular structural resonance of the valve, the valve components, and / or the fluid directed through the valve. [9] Canister purge valve (112) according to claim 1, wherein the two or more outlet openings (216) exit from a cylindrical surface (220) of a substantially cylindrical outlet tube (214).

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