Abstract:
A variable flow valve with position feedback is disclosed. The variable flow valve includes a housing having an inlet port and a discharge port and one or more control ports, and also includes a piston connected to a primary valve to open and close fluid communication between an inlet port and a discharge port of the housing. The housing and the piston intermesh to define an inner chamber and an outer chamber each in fluid communication with its own control port. A control port valve opens and closes at least one of the control ports to control access to a source of pressure change. A position sensor is part of the position feedback and communicates the position of the primary valve, relative to the discharge port, to a controller that operates the control port valve to hold the primary valve in a position where the discharge port is partially open.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/662,255, filed Jun. 20, 2012. 
     
    
     TECHNICAL FIELD 
       [0002]    This application relates to variable flow valves, more particularly, to such a valve having position control and metered control of the flow of fluids through the valve, including valves such as a compressor recirculation valve. 
       BACKGROUND 
       [0003]    Internal combustion engines, its mechanisms, refinements and iterations are used in a variety of moving and non-moving vehicles or housings. Today, for examples, internal combustion engines are found in terrestrial passenger and industrial vehicles, marine, stationary and aerospace applications. There are generally two dominant ignition cycles commonly referred to as gas and diesel, or more formally as spark ignited (SI) and compression ignition (CI), respectively. More recently, exhaust-driven turbochargers have been incorporated into the system connected to the internal combustion engine to improve the power output and overall efficiency of engine. 
         [0004]    Currently available valves used in turbocharger systems of internal combustion engines, such as a compressor bypass valve, operate such that they are either open or closed in response to changes within the system. These valves do not provide active control of the position of the valve. 
         [0005]    Herein compressor recirculation valves are disclosed that allow original equipment manufacturers (“OEMs”) or anyone using a turbocharger to actively control the position of this valve with precision not before envisioned. This level of control has the objective of more precise control of turbo speeds, which allows OEMS or others to keep the turbo speed higher and thereby reduce turbo response time and turbo lag and improve fuel economy and drivability of the vehicle. 
       SUMMARY 
       [0006]    In one aspect, internal combustion engines having an exhaust driven turbocharger system are disclosed that include a variable flow valve. In one embodiment, the variable flow valve may be a compressor bypass valve, but is not limited thereto. In the system the variable flow valve assists in controlling the exhaust driven turbocharging system. The turbocharger has its compressor outlet connected in fluid communication to the variable flow valve and also to an air inlet of an engine. The variable flow valve includes a position sensor that senses the position of the primary valve therein and communicates this position to a controller to control the opening and closing of the variable flow valve. In particular, the primary valve may be held in a position where the discharge port is partially open thereby affecting the flow of air into the air inlet of the engine. 
         [0007]    The variable flow valve include a housing having an inlet port and a discharge port and one or more control ports, and also includes a piston connected to a primary valve to open and close fluid communication between an inlet port and a discharge port of the housing to make the variable control possible. Here, the housing and the piston intermesh to define an inner chamber and an outer chamber each in fluid communication with its own control port. A control port valve opens and closes at least one of the control ports to control access to a source of pressure change. A position sensor is also part of the variable flow valve to communicate the position of the primary valve, relative to the discharge port, to a controller that operates the control port valve to hold the primary valve in the partially open position. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a diagram including flow paths and flow directions of one embodiment of an internal combustion engine turbo system that includes a compressor recirculation valve (“CRV”). 
           [0009]      FIG. 2  is a cross-sectional view of one embodiment of a compressor recirculation valve in an open position. 
           [0010]      FIG. 3  is a cross-sectional view of the compressor recirculation valve of  FIG. 2  in a closed position. 
       
    
    
     DETAILED DESCRIPTION 
       [0011]    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. 
         [0012]      FIG. 1  illustrates one embodiment of an internal combustion engine turbo system, generally designated  100 . The turbo system  100  includes the following components in controlling the operating parameters of a turbocharger: an exhaust-driven turbo charger (“EDT”)  2  with a turbine section  22  and compressor section  24 , a turbine bypass valve commonly referred to as a wastegate  13 , and a compressor recirculation valve  6  (shown in detail in  FIGS. 2 and 3 ). The EDT includes an exhaust housing  17 ,  18  containing a turbine wheel  26  that harnesses and converts exhaust energy into mechanical work through a common shaft to turn a compressor wheel  28  that ingests air, compresses it and feeds it at higher operating pressures into the inlet  11  of the internal combustion engine  10 . 
         [0013]    Still referring to  FIG. 1 , the wastegate  13  is a control valve used to meter the exhaust volume  16  coming from the exhaust manifold  12  of the internal combustion engine  10  and the energy available to power the EDT turbine wheel  26 . The wastegate  13  works by opening a valve (not shown) to bypass  19  so that exhaust flows away from the turbine wheel  26 , thereby having direct control over the speed of the EDT  2  and the resultant operating pressure of the ICE intake manifold. The wastegate  13  may have any number of embodiments, including the embodiments disclosed in applicant&#39;s U.S. patent application Ser. No. 12/717,130, which is incorporated by reference herein in its entirety. 
         [0014]    In any EDT system, there exists operating pressures in the compressor inlet  3 , intake manifold  5 ,  11  (IM), exhaust manifold  12 ,  16  (EM) and exhaust  18 ,  21 . With respect to  FIG. 1 , the EDT compressor inlet is defined as the passageway from the air intake system  1  to the inlet  3  of the EDT compressor section  24 , typically operating at an ambient pressure in a single stage EDT system. The engine&#39;s inlet manifold is defined as the passages between the EDT compressor discharge  4  and the ICE intake valve(s)  11 . The engine&#39;s exhaust manifold is defined as the passages between the ICE exhaust valve  12  and the EDT turbine inlet  17 . The exhaust is broadly defined as any passageway after the EDT turbine discharge  18 . In order to achieve effective exhaust gas recirculation (EGR), the pressures in the exhaust manifold should be significantly higher than the pressures found in the inlet manifold in order for exhaust gas to flow in that direction. The design of EDT and the varied combinations that exist of compressor and exhaust sizes is extensive. To summarize, smaller EDT exhaust profiles produce higher desired exhaust manifold pressures at the expense of lower efficiencies. One can appreciate that engineers in the art weigh a fine balance between achieving efficiency and EGR effectiveness. 
         [0015]    By definition, the compressor recirculation valve  6  is a regulating valve located in the passageway  5  between the discharge port  4  (also called an exhaust outlet) of a compressor section  24  of the EDT  2 , be it exhaust or mechanically driven, and the ICE inlet  11 . In the enlarged views in  FIGS. 2 and 3 , the CRV  6  includes a discharge port  8 . The discharge port  8  may be, but is not limited to, one that is vented to atmosphere or re-circulated back into the compressor&#39;s ambient inlet  3  (as shown in  FIG. 1 ). 
         [0016]    A CRV may be used on a spark ignited ICE with a throttle plate  9  as depicted in  FIG. 1 . At any given ICE operating range, the EDT can be spinning up to 200,000 revolutions per minute (RPM). The sudden closing of the throttle  9  does not immediately decelerate the RPM of the EDT  2 . Therefore, this creates a sudden increase in pressure in the passages between the closed throttle and EDT compressor section  24  such as passage  5 . The CRV  6  functions by relieving, or bypassing this pressure back to the flow path between the air induction system  1  and the compressor section  24 . 
         [0017]    The CRV  6  in  FIGS. 2-3 , is a multi-chambered valve capable of employment in any EDT enabled ICE, including diesels, and capable of controlling the opening and/or closing of the valve, even to various partial open positions, in response to signals from a position sensor  92  included as part of the valve. CRV  6  includes a housing  50  having an inlet port  7  and the discharge port  8 , one or more control ports  38  passing through the housing  50  that are connected to a control port valve  72  to open and close said control ports to access a source of pressure change (in  FIGS. 2-3 , an integral solenoid  70  with an armature is shown as the control port valve, but the invention is not limited thereto), and a piston  36  connected to a valve  30  seated within the housing. The housing  50  may be a one or two piece configuration. In a two piece embodiment, the housing may include a cover  80  and a main body  82 . The solenoid  70  may be directly mounted to the cover  80  with the armature  72  in the fluid flowpath  90  (illustrated by the double-headed arrow) connecting the one or more control ports  38  to a pathway  76  through the solenoid  70  to a vacuum  78  (one example of a source of a pressure change). The direct mounting of the solenoid  70  eliminates the need for connecting hoses, shortens the pathway for faster reaction time, and overall is a more compact construction with less components for potential future failure. Other examples of a source of pressure change is any type of pump for moving a fluid in a positive direction, a negative direction, or alternating therebetween such as, but not limited to, an air pump, a hydraulic pump, a fluid injector, a vacuum pump. 
         [0018]    The piston  36  includes a central shaft  40  having a first end  41  and a second end  42 . The first end  41  includes a sealing member  52  such as, but not limited to, an O-ring for sealing engagement with a first portion of the housing  50 . Extending from the second end  42  is a flange  44  extending toward the first end  41 , but spaced a distance away from the central shaft  40  of the piston  36 . The flange  44  terminates in a thickened rim  45  having a seat  54  for a second sealing member  56  such as, but not limited to, an O-ring. The second sealing member  56  also provide sealing engagement with a second portion of the housing  50 . The flange  44  defines a general cup-shaped chamber  46  (best seen in  FIG. 3 ) between the central shaft  40  and itself, and when housed inside housing  50  define a plurality of chambers  58 ′ (innermost) and  58 ″ (outermost). The piston  36  is movable between an open position (shown in  FIG. 2 ) and a closed position (shown in  FIG. 3 ) by the biasing spring  32 , by positive or negative actuating pressure (provided, for example, by vacuum) through fluid flowpath  90 , or a combination thereof. 
         [0019]    The sealing member be any suitable seal or washer for sealing reciprocating components, including a lip seal. In an embodiment where at least one of the sealing members  52 ,  56  is an O-ring, the O-ring may have one of various cross-sectional profiles including a circular profile, an X-shaped profile, a square profile, a generally V-shaped profile, a generally U-shaped profile or other profiles suitable for sealing reciprocating components. 
         [0020]    Still referring to  FIGS. 2 and 3 , the position sensor  92  may be any device that permits position measurement. In one embodiment, it is a relative position sensor (a displacement sensor) based on movement of the valve  30  relative to the opening it is seated in, whether in the inlet port  7  or the discharge port  8 . The position sensor  92  may be a capacitive transducer, an eddy-current sensor, a grating senor, a Hall-effect sensor, an inductive non-contact position sensors, a laser Doppler Vibrometer (optical), a linear variable differential transformer (LVDT), a multi-axis displacement transducer, a photodiode array, a piezo-electric transducer (piezo-electric), a potentiometer, a proximity sensor (optical), a seismic displacement pick-up, a string potentiometer (also known as string pot, string encoder, cable position transducer), or a combination thereof. 
         [0021]    In the embodiment illustrated in  FIGS. 2 and 3 , the position sensor  92  is a Hall effect sensor comprising a chip/Hall effect position sensor  96  that sensors the displacement of magnet  94 , which is connected to the valve  30  for translation therewith. The magnet  94  may be mounted to or within the piston  36  or the valve  30 , for example, the magnet  94  may be recessed into the valve  30  or the piston  36  (not shown). In  FIGS. 2 and 3 , the magnet  94  is housed within a bracket  98  connected to the piston  36 . The bracket  98  suspends the magnet  94  within the innermost chamber  58 ′ (labeled in  FIG. 3 ) defined between the piston  36  and the housing  50 . The bracket  98  includes one or more holes  102  therein leading into a pathway  104  through the valve  30  into fluid communication with the discharge port  8 . The holes in the bracket  98  also place the inlet port  7  (or discharge port  8 , depending upon the mounting orientation of the primary valve  30  within the housing  50  and the orientation of the CRV in the system), via pathway  104 , in fluid communication with the innermost chamber  58 ′. The chip/Hall effect position sensor  96  may be positioned within the actuator structure in sufficient proximity to sense the movement of the magnet  94 . In the embodiment in  FIGS. 2 and 3 , the chip/Hall effect position sensor  96  is oriented horizontally in a position above the magnet  94  as part of the cover  80 , i.e., axial relative to the magnet  94 . In another embodiment, the chip/Hall effect position sensor  96  may be oriented vertically in a position radially outward away from the magnet  94 . The innermost chamber also houses a biasing member  32  in such a way that the magnet  94  does not interfere therewith. 
         [0022]    Pathway  104 ,  FIG. 2 , is formed axially through the valve  30 . 
         [0023]    As discussed above, the control port valve  72  may be solenoid  70  and its armature  72  operable in response to instructions from a CPU  106  to turn on the selenoid  70  to move the armature  72  to open the fluid flowpath  90  ( FIG. 2 ) between the outermost chamber  58 ″ and the source of pressure change  78 . 
         [0024]    The present invention enables the ICE engineer to control the operating pressure of the exhaust manifold  12 ,  16  on command. By selectively opening the CRV  6 , see  FIG. 3 , to a desired displacement, including a plurality of partial open positions, relative to the opening its seated in when in a closed position, the operating pressures can be controlled to produce a desired effect. In one embodiment, the operator is effectively controlling the operating pressure of the engine&#39;s intake manifold  5 ,  11  by utilizing the CRV  6 . There exists several methodologies for controlling the opening and closing of embodiments of a CRV  6  that can produce the Effect. In one embodiment, the CRV  6  can be made to open naturally against a biasing spring  32 , where when operating pressure exceeds the pre-load force of the spring, the CRV  6  opens and then regulates against the pre-load force to maintain a given operating pressure at the intake manifold  5 ,  11  ( FIG. 1 ). Once signaled open, the CRV  6  operates similar to the previous example. Additionally, CRV  6 , direct-acting or pneumatic, may be signaled to open by having a circuit apply a control frequency with a given duty cycle in order to produce a target operating pressure in the intake manifold  5 ,  11  against which to regulate, or perhaps determine the lift and position of the valve  30  in the CRV  6 . 
         [0025]    Herein, as seen in  FIGS. 2 and 3 , the selective metering (partial opening of the valve to a plurality of positions) is accomplished using the CPU  106  and the signals the CPU  106  receives from the position sensor  92 . The selective metering is enhanced by the geometry of the valve seat  110  and the valve  30 . In particular, the valve seat  110  and the valve  30  are shaped such that a slight displacement of the valve can partially open the discharge port. 
         [0026]    A variety of control methodologies are known, or may be developed hereafter, that enable the sensing of system operating pressures or referencing the system operating pressure against the mechanical operation of a valve therein and thereafter produce an output to achieve an Effect. The system arrangements can be as fundamental as pneumatically communicating pressure signals that are produced in the system are to a mechanical actuators surface area acting against a spring bias. As system conditions change, then the performance of the actuator will change accordingly in a simple closed-loop logic. The control system can also increase in complexity to include pressure sensors that communicate signals to an electronic processing unit that integrates those signals electronically, or against a table of comparative values, and then output a control signal to a solenoid that will pneumatically control the actions of the actuator. As discussed in U.S. patent application Ser. No. 13/369,971, which is incorporated herein by reference in its entirety, the control of a valve in the position of the CRV  6  in  FIG. 1  may be coordinated with the opening and closing of the wastegate  13  to control the boost pressure at the intake manifold  5 ,  11 . 
         [0027]    Having described the invention in detail and by reference to preferred embodiments thereof, it will be apparent that modifications and variations are possible without departing from the scope of the invention which is defined in the appended claims.