Patent Description:
In automotive engines, on/off operation of a vacuum generator and/or accessory is frequently controlled by a gate valve in which a rigid gate is deployed across a conduit to stop the flow of a fluid (in this exemplary application, air) through the valve. Within automated or "commanded" valves, the gate is typically actuated by a solenoid and opened or closed in response to an electrical current applied to the solenoid coil. These solenoid-powered gate valves also tend to include a coil spring, diaphragm, or other biasing element which biases the gate towards an unpowered, 'normally open' or 'normally closed' position.

The pressure in an engine crankcase is ideally maintained near atmospheric pressure (ATM pressure +/- <NUM> kPa). Furthermore, it is desirable to be able to detect any leak in the crankcase ventilation system (path from fresh air to the manifold, including all flow passageways and passageway connections) to ensure crankcase gasses are appropriately managed to avoid excessive pollutants being discharged into the atmosphere. In order to achieve these conditions, free flow (minimal restriction) of air into the crankcase is needed, which can be switched to a restricted opening, in order to conduct a pressure integrity check (and not create an excessively negative pressure in the crankcase). The gate valve approach while successful, is more expensive and takes up engine space. A more cost effective and compact system to enable the pressure integrity check of the crankcase ventilation system is desirable, especially one as disclosed herein that does not require any electrical connections to move an actuator, such as a solenoid, to operate a valve.

An example is provided by <CIT>, which discloses a load sensitive proportion multiple unit valve guide control with hydraulic pressure steady voltage attenuator.

In this connection, <CIT> discloses a method and apparatus for controlling relative movement such as rotary movement between a railway truck and a car body supported thereby to control truck hunting through application of reaction forces resisting such rotary movement which are effective primarily to resist higher velocity relative rotational movements.

In this respect, <CIT> concerns a hydraulic control device, comprising at least one directional control valve which is connected to a pump and return line and from which at least one consumer line (leads to a hydraulic consumer, a fixed displacement pump supplying a pump line via a regulating valve, and a control-pressure circuit in which a control pressure dependent upon the load pressure in the consumer line can be controlled, the regulating valve of which can be acted upon on a closing-pressure side by the control pressure from the control circuit and by spring force as well as on an opening-pressure side by the pump pressure, has a hydraulic, mechanically preloaded, opening-movement damping device between the closing-pressure side and the control circuit, which opening-movement damping device can be automatically cut out if a predetermined pressure difference between the higher control pressure applied to the closing-pressure side and the lower control pressure prevailing in the control circuit is exceeded.

For example, <CIT> discloses a damping unit has a single intake connection and located behind it a branch divides into two parallel conduits. The conduits contain opposite back pressure valves, and they are united in front of a single outlet connection. A throttle element e.g. a nozzle is located between the conduit connection point and the outlet connection. Conduits, seats for the valves, and the throttle are e.g. formed by bores in a rigid housing block.

Other examples are disclosed in <CIT>, <CIT> or <CIT>.

The present invention discloses a flow control device and a crankcase ventilation breach detection system of an internal combustion engine according to the appended claims.

The following detailed description will illustrate the general principles of the invention, examples of which are additionally illustrated in the accompanying drawings. In the drawings, like reference numbers indicate identical or functionally similar elements.

As used herein, "fluid" means any liquid, suspension, colloid, gas, plasma, or combinations thereof.

<FIG> illustrates one embodiment of an engine system <NUM>, which may be a vehicle engine system that is a turbocharged or supercharged system. The engine system <NUM> is configured for combusting fuel vapor accumulated in at least one component thereof and includes a multi-cylinder internal combustion engine <NUM>. The engine system <NUM> receives air from an air intake <NUM>, which may include an air filter <NUM> (also known as an air cleaner). The engine system of <FIG> is a turbocharged engine system having a turbocharger <NUM>, but could just as equally be a supercharged engine system. The compressor <NUM> of the turbocharger <NUM> receives air from the air intake <NUM>, compresses the air, and directs a flow of compressed air (or boosted air) downstream through a charge air cooler or intercooler <NUM> and then to a throttle <NUM>. The throttle <NUM> controls fluid communication between the compressor <NUM> and the intake manifold <NUM> of the engine <NUM>. The throttle <NUM> is operable using known techniques to vary an amount of intake air provided to the intake manifold <NUM> and the cylinders of the engine. In alternative embodiments, the intercooler <NUM> may be positioned downstream of the throttle, and as such, may be housed in the intake manifold.

Still referring to <FIG>, intake manifold <NUM> is configured to supply intake air or an air-fuel mixture to a plurality of combustion chambers of engine <NUM> located within the engine block <NUM>. The combustion chambers are typically arranged above a lubricant-filled crankcase <NUM> such that reciprocating pistons of the combustion chambers rotate a crankshaft (not shown) located in the crankcase <NUM>. Unburned fuel and other combustion products may escape past each piston and/or valve guides from the engine block into the crankcase <NUM>. The resulting gases in the crankcase, often referred to as "blow-by" gases may excessively pressurize the crankcase <NUM> if not vented therefrom. Engine <NUM> includes a crankcase ventilation system, which serves to vent blow-by gases from the crankcase <NUM> to intake manifold <NUM>.

Still referring to <FIG>, the crankcase ventilation system includes a positive crankcase ventilation valve <NUM> in fluid communication between the crankcase <NUM> and the intake manifold <NUM>, to regulate the flow of blow-by gases from the crankcase to the intake manifold, and a conduit known as a crankcase ventilation tube <NUM> placing the crankcase <NUM>, in particular, the blow-by gas in fluid communication with clean air from the air intake <NUM>. Here, the crankcase ventilation tube <NUM> is in fluid communication upstream of the compressor <NUM>. The crankcase ventilation tube <NUM> divides into a flow control system <NUM> that includes a pressure sensor <NUM> positioned between the flow control system <NUM> and the crankcase <NUM>. In the flow control system detection of no pressure differential by the pressure sensor <NUM> indicates a breach in the system.

As represented by the box surrounding the flow control system and, optionally, the pressure sensor <NUM>, rather than being separate conduits, check valves, restriction, and sensor, these are integrated as flow control device <NUM>, shown in more detail in the embodiments in <FIG>. The flow control system <NUM> in the embodiment of <FIG> and hence the flow control device <NUM> include three parallel conduits, one conduit <NUM> defines a restriction profile <NUM>, another conduit <NUM> has a normally closed check valve <NUM> controlling flow therethrough from the air intake to the crankcase, and yet another conduit <NUM> has a normally neutral check valve <NUM> controlling flow therethrough from the crankcase to the air intake. The normally closed check valve <NUM> opens under a first preselected pressure differential, the second check valve opens under a second preselected pressure differential, and the restriction profile has a third preselected pressure differential that is the same in either direction of flow therethrough. As labeled in <FIG>, a first direction D<NUM> (the normal flow direction) is from the air intake upstream of the compressor to the crankcase and the second direction D<NUM> is the opposite of the first direction. Flow in the first direction D<NUM> through the flow control device <NUM> is through the open hemispherical poppet check valve as shown by the arrows in <FIG>. Flow in the second direction D<NUM> through the flow control device <NUM> is through the open normally neutral check valve as shown by the arrows in <FIG>.

A "normally closed" check valve is in the closed position until the pressure differential (change in pressure) between the inlet and the outlet is sufficient to overcome the spring holding the poppet in the closed position. A "normally neutral" check valve is neither open nor closed and depends on sufficient pressure differential to overcome the minimal mass of the disc to be in either the open or closed position, depending on the flow direction. The normally closed check valve <NUM> can be tuned to open within <NUM> kPa to <NUM> kPa of the preselected pressure differential of a control system for a particular engine system based on the setpoints selected for said engine system. In one embodiment, the preselected pressure differential is a change of about <NUM> kPa. When used as a "normally closed" check valve the opening pressure differential can be tuned by varying the spring rate and preselected spring force at installation of the spring.

The flow control system of <FIG> is set to have the first preselected pressure differential of the normally closed check valve <NUM> greater than or equal to the third pressure differential of the restrictor <NUM>, and the second pressure differential of the normally neutral check valve <NUM> is the same or less than the third pressure differential of the restrictor <NUM>. The first, second and third pressure differentials are in a range of about <NUM> kPa to about <NUM> kPa, more preferably about <NUM> kPa to about <NUM> kPa. "About" herein means +/- <NUM> kPa. In one embodiment, the normally closed check valve <NUM> opens at about a <NUM> kPa pressure differential at <NUM> slpm and at about a <NUM> kPa pressure differential at <NUM> slpm, while the normally neutral check valve <NUM> opens at about a <NUM> kPa pressure differential at <NUM> slpm and at about a <NUM> kPa pressure differential at <NUM> slpm, with the restrictor orifice being continuously open and constructed for a <NUM> kPa pressure differential at <NUM> slpm.

Turning now to <FIG>, a first embodiment of a flow control device <NUM> is disclosed that has a housing <NUM> having a first housing portion <NUM> defining a first port <NUM> and a second housing portion <NUM> defining a second port <NUM> that are sealingly fixed together with a fluid-tight seal at flange <NUM> and collectively define an internal cavity <NUM>. The first port <NUM> and the second fluid port <NUM> are both in fluid communication with the internal cavity <NUM>. The internal cavity <NUM> has larger dimensions than the first port <NUM> and the second port <NUM> and splits into three parallel conduits <NUM>, <NUM>, <NUM> each of which are in fluid communication with the first port <NUM> and the second port <NUM>. In the illustrated embodiment, the first port <NUM> and the second port <NUM> are positioned opposite one another to define a generally linear flow path through the flow control device <NUM>, but is not limited to this configuration. In another embodiment, the first and second ports may be positioned relative to one another at an angle of less than <NUM> degrees. Each of the exterior ends of the first port <NUM> and the second port <NUM> can include connecting features <NUM>, such as flanges, ribs, grooves, barbs, etc. to attach a hose thereto or a duct of a device within the engine system. The first port <NUM> may include a sensor port <NUM> for a sensor such as a pressure sensor to detect changes in pressure that will indicate a leak in the engine system. Alternately, a sensor may be placed in the system between the first port and the crankcase.

Referring to <FIG> the first conduit <NUM> defining the restrictor <NUM> is generally positioned centrally in the flow control device <NUM> between the normally closed check valve <NUM> and the normally neutral check valve <NUM>. In this embodiment, the first conduit <NUM> is aligned with the first port <NUM> and the second port <NUM> along a central longitudinal axis A of the housing. The first conduit <NUM> may be molded of a suitable plastic separately from the first housing portion <NUM> and the second housing portion <NUM> and is inserted therein in registration therewith using mating registration features <NUM>, <NUM>. The restrictor <NUM> has an internal profile having upstream and downstream portions <NUM>, <NUM> converging toward one another and defining a throat <NUM> where the two meet. Both portions <NUM>, <NUM> are circular, when viewed in a transverse cross-section, and each narrow according to a parabolic or hyperbolic function along its length, which meet at the throat <NUM>. The internal profile of the upstream and downstream portions <NUM>, <NUM> may be symmetrical, mirror image of one another. The throat diameter is the parameter that determines or sets the maximum mass flow rate. A larger diameter for the throat equates to a larger mass flow rate. Here, the throat diameter is in a range of about <NUM> to <NUM>, more preferably about <NUM> to about <NUM>. For the throat diameter, "about" means +/- <NUM>.

The normally closed check valve <NUM> is a hemispherical poppet check valve that is spring biased into the closed position as illustrated in <FIG> and <FIG>. The hemispherical poppet check valve <NUM> has an internal cavity <NUM> defined by the fluid tight connection of the first housing portion <NUM> and the second housing portion <NUM>. The internal cavity <NUM> is generally spherically shaped and defines an annular seat <NUM> for engagement with a hemispherical poppet sealing member <NUM>, which is translatable between a closed position against the annular seat <NUM> (<FIG> and <FIG>) and an open position (<FIG>). The generally spherical shape of the internal cavity <NUM> complements the shape of the hemispherical poppet sealing member <NUM> and provides a low restriction flow path in the open position. The annular seat <NUM> in a longitudinal cross-section through the check valve <NUM>, as shown in <FIG>, defines a convex spherical radius as indicated by arrow <NUM> in <FIG>. The convex spherical radius of the annular seat <NUM> is preferably positioned or formed at a transition from the first port <NUM> into the internal cavity <NUM>. The internal cavity <NUM> has a generally spherical shape as noted above and, in the closed position, a convex surface of the hemispherical poppet sealing member <NUM> as indicated by arrow <NUM> in <FIG> is engaged with the convex spherical radius <NUM> of the annular seat <NUM>.

Referring to <FIG>, the convex surface-convex surface seal is shown as an enlarged image. This seal forms a tangent seal interface that is insensitive to slight misalignment of the hemispherical poppet sealing member <NUM> when closing. A slightly misaligned hemispherical poppet sealing member will still have good seal integrity, approximately <NUM> scc/m or less. As seen, the interior of the first housing portion <NUM> has, in a longitudinal cross-section, a partial "S" shaped curve centered about the convex spherical radius <NUM> that defines gaps <NUM>, <NUM> between the hemispherical poppet sealing member and the housing above and below the convex surface-convex surface seal, based on the orientation of the figure to the page.

Turning back to <FIG>, to aid in seal alignment, the internal cavity <NUM> has a pin <NUM> centrally positioned and protruding into the cavity opposite the annual seat <NUM>. The hemispherical poppet valve <NUM> has a cupped underside <NUM> defining a first seat <NUM> for the spring <NUM> and has a hollow stem <NUM> protruding from the cupped underside <NUM> toward the pin <NUM> and receives the pin <NUM> therein for translation of the hemispherical poppet sealing member <NUM> along the pin <NUM>. When spring <NUM> is present, a first end <NUM> of the spring <NUM> is seated and retained by first seat <NUM> in the cupped underside <NUM> of the hemispherical poppet sealing member <NUM> and a second end <NUM> of the spring <NUM> is seated and retained be a second seat <NUM> defined by the second housing portion <NUM> and protruding into the internal cavity proximate a base <NUM> of the pin <NUM>. The cupped underside <NUM> of the hemispherical poppet sealing member <NUM> provides a large restriction to fluid flow in the "non-flow direction" represented by the arrows in <FIG>, thereby producing sufficient force to translate the sealing member to the closed position, even without the spring force provided by the spring, if desired.

Referring to <FIG>, in all embodiments, one or both of the annular seat <NUM> and the hemispherical poppet sealing member <NUM> can include a ring of elastomeric sealing material <NUM> (<FIG>) to define the convex spherical radius <NUM> of the annular seat <NUM> or to define the portion of the convex surface <NUM> of the hemispherical poppet sealing member <NUM> (<FIG>) that engages the annular seat <NUM> in the closed position. However, as shown in <FIG>, a ring of elastomeric sealing material is not required. The ring of elastomeric sealing material <NUM> matches (is flush with) the partial "S" shaped curved contour of the first housing portion <NUM> so as not to create a flow restriction, in the open position and the ring of elastomeric sealing material <NUM> matches (is flush with) the hemispherical surface of the hemispherical poppet sealing member <NUM> so as not to create a flow restriction, in the open position. The ring of elastomeric sealing material <NUM>, <NUM> is insert molded or co-molded as part of one or both of the annular seat <NUM>, i.e., first housing portion <NUM>, and the hemispherical poppet sealing member <NUM>. Either or both of the rings of elastomeric sealing material <NUM>, <NUM> may include an annular lip <NUM> best seen in <FIG> to help retain the molded elastomeric sealing material <NUM>, <NUM> in place in its respective member.

The ring of elastomeric sealing material may be formed of a fluoroelastomer. Suitable fluoroelastomers include, but are not limited to, polyvinyl fluoride, polyvinylidene fluorides, polytrifluoromonochloroethylene, polytetrafluoroethylene, polyhexafluoropropylene, polydifluoroethylene, polytetrafluoroethylene, fluorosilicone, ethylene-tetrafluoroethylene copolymer, hexafluoropropylene-tetrafluoroethylene copolymer, hexafluoropropylene-difluoroethylene copolymer, perfluoroalkoxytetrafluoroethylene copolymer, tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride terpolymer, or other commercially available elastomeric material that will provide seal integrity at both low pressure differentials (such as <NUM> kPa) and at high pressure differentials (such as <NUM> kPa), and blends thereof.

In all embodiments, the hemispherical poppet sealing member <NUM> has a cupped underside <NUM> defining an outer rim <NUM>. Referring now to <FIG>, the outer rim <NUM> can include an elastomeric flange <NUM> extending radially outward that, in the closed positioned, forms a clearance fit or an interference fit with a surface of the internal cavity <NUM>. This elastomeric flange <NUM> enhances the ability of the hemispherical poppet sealing member <NUM> to close under low reverse flow conditions. The elastomeric flange <NUM> is insert molded or co-molded to the hemispherical poppet sealing member <NUM> and may include a head <NUM> inserted into the hemispherical poppet sealing member <NUM> as shown in <FIG>. The elastomeric flange <NUM> as shown in <FIG> may include a hinge feature <NUM> that allows the elastomeric flange <NUM> to bend out of the way in response to the pressure differentials in the system to maintain minimal restrictions on the fluid flow through the check valve in the open position, i.e., the flange <NUM> bends away from the surface of the internal cavity <NUM> toward the stem <NUM> and the pin <NUM>.

With reference to all embodiments, best seen in <FIG>, the first housing portion <NUM> terminates away from the first port <NUM> with a double flanged end <NUM>, wherein an interior flange <NUM> of the double flange is shorter than an exterior flange <NUM> of the double flange and the interior flange <NUM> is contoured to lie radially inward of a rim <NUM> of the second housing portion <NUM> to collectively define the generally spherical shape of the internal cavity <NUM>. The spherical radius and/or the radial position of spherical radius center of the first housing portion's profile is slightly less than the spherical radius and/or the radial position of spherical radius center of the second housing portion's profile, which creates an "overlap" of the interior flange <NUM> with the rim <NUM> described above and provides a low restriction flow path as well as low audible noise in the check valve <NUM>.

The exterior flange <NUM> of the first housing portion <NUM> and the rim <NUM> of the second housing portion <NUM> can have a snap-fit connection <NUM> as shown in <FIG>. In all embodiments, the first housing portion <NUM> and the second housing portion <NUM> can be formed of a plastic material suitable for combustion engine environments and can be spin-welded together. As shown in <FIG>, the double flange end <NUM> of the first housing portion <NUM> can include an annular bead of sealing material <NUM> between the interior flange <NUM> and the exterior flange <NUM> to provide additional material for the spin weld.

Referring again to <FIG>, the open end <NUM> of the stem <NUM> and the head <NUM> of the pin <NUM> can have snap-fit features <NUM> to assist in maintaining the position of the hemispherical poppet sealing member <NUM> during assembly of the check valve <NUM>.

Turning now to <FIG>, the normally neutral check valve <NUM> has an internal cavity <NUM> defined within the third conduit <NUM> formed by the fluid tight connection of the first housing portion <NUM> to the second housing portion <NUM>. The normally neutral check valve <NUM> has a pin <NUM> defined by one of the first or second housing portions <NUM>, <NUM> and the other housing portion defines a sleeve <NUM> in which the pin <NUM> is received when the first and second housing portions are mated together. The sealing disk <NUM> has a central bore <NUM> therethrough that receives the pin <NUM> such that the sealing disc <NUM> is seated upon the pin <NUM>. The sealing disc <NUM> floats and translates along the pin <NUM> between an open position and a closed position based on pressure differentials in the system. The sealing disc <NUM> is not a spring biased sealing member.

The portion of the housing <NUM> defining the internal cavity <NUM> includes an internal first seat <NUM>, here collectively a first annular seal bead <NUM> and a second annular seal bead <NUM>, upon which the sealing disc <NUM> seats when the check valve is "closed," as shown in <FIG> and <FIG>. The second annular seal bead <NUM> is radially inward of the first annular seal bead <NUM>. A second seat <NUM> is defined by a plurality of radially spaced fingers <NUM> extending into the internal cavity <NUM> from an interior surface of the internal cavity that is more proximate the second port <NUM> and the air box of the engine system. The plurality of radially spaced apart fingers <NUM> have a pre-selected length that provides a distance between the first seat <NUM> and the second seat <NUM>, thereby enabling the sealing disc <NUM> to translate along the pin from the closed position to the open position. In the open position the sealing disc <NUM> is elastically flexed against the plurality of radially spaced fingers <NUM> as shown in <FIG>.

The pin <NUM> is typically centrally positioned within the internal cavity <NUM> and a plurality of ribs <NUM> comprising connecting ribs and/or partial ribs <NUM> as disclosed in any of the configurations disclosed in <CIT> extend radially outward from the pin <NUM> or toward the pin <NUM> to subdivide the flow path into a plurality of conduits to direct the fluid flow around the periphery of the sealing disk <NUM> as shown by the arrows in <FIG> when the check valve <NUM> is elastically flexed in the open position.

The sealing disk <NUM> can have a constant thickness across its diameter as illustrated in the figures, thereby being a flat planar disc, or it can be a stepped disk as described in co-owned <CIT>. The sealing disc <NUM> is elastically flexible to bend toward the second seat <NUM> in response to a preselected pressure differential across the normally neutral check valve <NUM>. The sealing disc <NUM> transforms between a flat shape in the closed position to a shallow bowl shape in the open position and back again. The sealing disc <NUM> readily flexes when there is a pressure differential from the side of the first seat <NUM> to the second seat <NUM>, i.e., higher pressure is at the first seat <NUM>.

The sealing disc <NUM> may be or include an elastomeric material suitable for use in fluid communication with blow-by-gas from the crankcase ventilation system of an internal combustion engine, i.e., is durable when exposed to temperatures and pressures associated with such an environment. In one embodiment, the sealing disc <NUM> may be or include one or more of a natural rubber, synthetic rubber, silicone rubber, fluorosilicone rubber, fluorocarbon rubber, nitrile rubber, EPDM, PTFE, and combinations thereof, but is not limited thereto.

Turning now to <FIG>, the graph of the flow rate versus the pressure drop experienced at the crankcase shows that in manifold vacuum there is a detectable amount of pressure drop to meet diagnostic requirements, but minimal increase in pressure drop as flow increases so as not to cause engine damage, while in manifold boost there is minimal pressure drop as desired. This allows diagnostic compliance anytime there is manifold vacuum.

Turning now to <FIG>, a second embodiment of a flow control device, generally designated <NUM>, is disclosed that has a housing <NUM> having a first housing portion <NUM> defining a first port <NUM> and a second housing portion <NUM> defining a second port <NUM> that are sealingly fixed together with a fluid-tight seal at flange <NUM> and collectively define an internal cavity <NUM>. The first port <NUM> and the second fluid port <NUM> are both in fluid communication with the internal cavity <NUM>. The internal cavity <NUM> has larger dimensions than the first port <NUM> and the second port <NUM> and splits into three parallel conduits <NUM>, <NUM>, <NUM>, each of which are in fluid communication with the first port <NUM> and the second port <NUM>. The first conduit <NUM> defines a restriction profile <NUM>, the second conduit <NUM> has a normally closed check valve <NUM> controlling flow therethrough from the air intake to the crankcase, and the third conduit <NUM> has a normally neutral check valve <NUM> controlling flow therethrough from the crankcase to the air intake. The normally closed check valve <NUM> opens under a first preselected pressure differential, the second check valve opens under a second preselected pressure differential, and the restriction profile has a third preselected pressure differential that is the same in either direction of flow therethrough. Flow in the first direction D<NUM>, from the air box to the intake manifold, through the flow control device <NUM> is through the open hemispherical poppet check valve as shown by the arrows in <FIG>. Flow in the second direction D<NUM> through the flow control device <NUM>, from the intake manifold to the air box, is through the open, normally neutral check valve as shown by the arrows in <FIG>. In this embodiment, the first port <NUM> and the second port <NUM> are positioned opposite one another to define a generally linear flow path through the flow control device <NUM>, but are not limited to this configuration. In another embodiment, the first and second ports may be positioned relative to one another at an angle of less than <NUM> degrees.

Each of the exterior ends of the first port <NUM> and the second port <NUM> can include connecting features, such as flanges, ribs, grooves, barbs, etc. to attach a hose thereto or a duct of a device within the engine system. In the embodiment of <FIG>, the second port <NUM> includes a connecting feature <NUM>, a cap for permanent connection to a duct of a device within the engine system, such as the air box. The cap <NUM> has a dual flanged terminal end <NUM> which receives a rim of the duct between the flanges. The dual flanged terminal end <NUM> lends itself to spin-welding the flow control device <NUM> to the duct. Alternately, the dual flanged terminal end can be attached to the duct by adhesive, other forms of welding, such as vibration welding or induction welding, heat-bonding, laser-bonding, or other methods known for mating plastic components in engine systems.

The first port <NUM> includes a sensor port <NUM> for a sensor such as a pressure sensor <NUM>, shown in <FIG>, to detect changes in pressure that will indicate a leak in the engine system. The pressure sensor <NUM> includes an electrical plug <NUM> for connection to an electrical source. The sensor portion of the pressure sensor <NUM> is in fluid communication with the sensor port <NUM> to be able to sense or measure parameters of the fluid and/or fluid flow within the flow control device.

Turning back to <FIG>, the first conduit <NUM> defining the restrictor <NUM> is generally positioned centrally in the flow control device <NUM> between the normally closed check valve <NUM> and the normally neutral check valve <NUM>. As described above for the first embodiment, the first conduit <NUM> is aligned with the first port <NUM> and the second port <NUM> along a central longitudinal axis A of the housing. The first conduit <NUM> may be molded of a suitable plastic separately from the first housing portion <NUM> and the second housing portion <NUM> and is inserted therein in registration therewith using mating registration features <NUM>, <NUM>. The restrictor <NUM> has the same characteristics, internal profile, and parameters described above.

In all aspects, the flow control devices have a housing that is typically molded of plastic, such as, but not limited to, nylon <NUM>, nylon <NUM>/<NUM>, nylon <NUM>/<NUM> and/or polyoxymethylene. The sealing members of the check valve may be constructed of a fluoroelastomer. Suitable fluoroelastomers include, but are not limited to, polyvinyl fluoride, polyvinylidene fluorides, polytrifluoromonochloroethylene, polytetrafluoroethylene, polyhexafluoropropylene, polydifluoroethylene, polytetrafluoroethylene, fluorosilicone, ethylene-tetrafluoroethylene copolymer, hexafluoropropylene-tetrafluoroethylene copolymer, hexafluoropropylene-difluoroethylene copolymer, perfluoroalkoxytetrafluoroethylene copolymer, tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride terpolymer, or other commercially available elastomeric material that will provide seal integrity at both low pressure differentials (such as <NUM> kPa) and at high pressure differentials (such as <NUM> kPa), and blends thereof. The flow control device is constructed of materials suitable for operation under a pressure range of <NUM> kPa to -80kPa and a temperature range of -<NUM> to <NUM>. The flow control device is typically about <NUM> to about <NUM> in length, more preferably about <NUM> to about <NUM> in length.

The advantages and/or benefits of the flow control device include a simplified design of reduced size that does not require electromotive controls (i.e., it is a passive device) for either check valve and reduces the number of hose connection points. The reduced number of connections eliminates costs and potential leak points. Further, the flow control devices has a tunable normally closed check valve (adjust the spring, i.e., the spring force applied to the poppet sealing member) and a tunable restrictor by preselecting an orifice size suitable for the engine system, and customizable end connector sizes and styles, for example an end that connects permanently to the air box as shown in <FIG>. The spring can be tuned to open at a higher or lower pressure differential for different engine sizes.

In operation, the flow control device provides the advantage of enabling a pressure sensor to continuously check for leaks up- and down-stream of the flow control device due to constant flow through the restrictor's preselected orifice size. If the normally closed check valve does not open, the pressure sensor will sense an increased vacuum level, which will cause an error detection. And, if the normally neutral check valve fails to open, the pressure sensor will sense a higher pressure, which will cause an error detection.

Furthermore, the hemispherical poppet check valve provides additional advantages to the flow control device, such as a check valve that opens under low differential pressure and has low flow restriction once open. The low flow restriction in the open position is a result of the combined shapes of the generally spherical internal cavity and the upper surface of the hemispherical poppet sealing member (see the flow arrows in <FIG>), more particularly, the internal flange of the first housing portion overlapping the rim of the second housing portion and defining matching contours once sealingly fixed together. This configuration also provides low audible noise when open and a no-leak seal when closed. Another advantage is that the check valve is not sensitive to the orientation of the flow control device in an engine system because the hemispherical poppet sealing member has a low mass, and does not move to the closed or open position under its own mass.

It should be noted that the embodiments are not limited in their application or use to the details of construction and arrangement of parts and steps illustrated in the drawings and description. Features of the illustrative embodiments, constructions, and variants may be implemented or incorporated in other embodiments, constructions, variants, and modifications, and may be practiced or carried out in various ways. Furthermore, unless otherwise indicated, the terms and expressions employed herein have been chosen for the purpose of describing the illustrative embodiments of the present invention for the convenience of the reader and are not for the purpose of limiting the invention.

Claim 1:
A flow control device (<NUM>) comprising:
a housing (<NUM>) defining a plurality of parallel conduits (<NUM>, <NUM>, <NUM>) comprising:
a first conduit (<NUM>) having a normally closed check valve (<NUM>) controlling flow through the first conduit (<NUM>), wherein the normally closed check valve (<NUM>) opens under a first preselected pressure differential in a first direction (D1) of flow;
a second conduit (<NUM>) having a normally neutral check valve (<NUM>) that opens under a second preselected pressure differential in a second direction (D2) of flow that is opposite the first direction (D1) of flow; and
a third conduit (<NUM>) defining a restriction profile that is continuously open and having a third preselected pressure differential;
characterized in that
the flow control device (<NUM>) has a first port (<NUM>) in fluid communication with all of the plurality of parallel conduits (<NUM>, <NUM>, <NUM>) and defines a sensor port (<NUM>) in the first port (<NUM>) for connection to a pressure sensor (<NUM>), and a pressure sensor (<NUM>) operatively connected to the sensor port (<NUM>).