Abstract:
A valve having a valve body with an inlet port and an outlet port and a valve disposed between the inlet port and outlet port. A sensor is operably associated with the valve and the valve body, and measures a characteristic in proximity to the valve. The sensor communicates information regarding said characteristic to a control unit that sends position commands to said valve.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 60/834,984, filed Aug. 2, 2006. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a valve having an integrated sensor. 
     BACKGROUND OF THE INVENTION 
     Valves having position sensors often have a set of predetermined valve positions that correlate to predetermined engine operating conditions. These predetermined conditions do not compensate for changes in operating conditions that are not part of the control unit&#39;s program. For example, as the components of the valve wear, contamination begins to build up inside the valve causing the flow of gas through the valve to be affected. The control unit has no way of adjusting operations in response. Therefore, there exists a need to compensate for changes in gas flow and adjust the position of the valve. 
     SUMMARY OF THE INVENTION 
     The present invention is a valve having a valve body with an inlet port and an outlet port and a valve disposed between the inlet port and outlet port. A sensor is operably associated with the valve and the valve body and measures a characteristic in proximity to the valve. The sensor communicates information regarding the characteristic to a control unit that sends position commands to the valve. 
     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating the preferred embodiment of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
         FIG. 1  a schematic of an engine intake and exhaust system incorporating an exhaust gas return valve, according to the present invention; 
         FIG. 2  is a sectional side view of a system with an EGR valve having a solenoid as an actuator, according to the present invention; and 
         FIG. 3  is an exhaust gas return system having a pressure sensor incorporated into the EGR valve, and a pressure sensor located in the intake manifold, according to the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following description of the preferred embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
     An exhaust gas recirculation (EGR) system is shown in  FIG. 1  generally at  10 . The system  10  includes an engine  12  which has an intake manifold  14  and an exhaust manifold  16 . The exhaust manifold  16  feeds exhaust gas from the engine  12  into a turbocharger unit  18 . The turbocharger unit  18  has a turbine  20 , and a compressor  22 . The compressor  22  includes an inlet pipe  24  for receiving air from the atmosphere and feeding it into an intercooler  26 . The intercooler  26  is connected to a throttle valve  28 , the throttle valve  28  is used for controlling the flow of air into the intake manifold  14 . 
     The system  10  also includes an EGR valve  30  for controlling the flow of exhaust gas from the exhaust manifold  16  to the intake manifold  14 . There is a first conduit  32  which is connected between the exhaust manifold  14  and the EGR valve  30 , and a second conduit  34  connected between the EGR valve  30  and the intake manifold  14 . Both the throttle valve  28  and the EGR valve  30  are controlled by an electronic control unit (ECU)  36 . 
     Referring now to all of the figures, a cross sectional view of the EGR valve  30  is shown. The EGR valve  30  is actuated by an actuator  38 . The actuator  38  in this embodiment is a solenoid. The EGR valve  30  has a valve body  40  with an inlet port  42  and an outlet port  44 . Located between the inlet port  42  and the outlet port  44  is a valve  50  having a valve stem  52 , and a valve member  54 . The valve member  54  rests against the valve seat  56  when the valve  50  is in the closed position. The inlet port  42  is in fluid connection with the first conduit  32 , and the outlet port  44  is in fluid connection with the second conduit  34 . 
     Also included in the valve body  40  is a first passage  46  and a second passage  48 ; the valve seat  56  has a first side  58  and a second side  60 . The first passage  46  is connected to the second side  60  of the valve seat  56  and the second passage  48  is connected to the first side  58  of the valve seat  56 . The first passage  46  and second passage  48  are operably connected to the flow path through the valve body. A sensor  62 , which in this embodiment is a pressure sensor, is integrated into the valve body  40 , and is located in the first passage  46  and the second passage  48 . The placement of the sensor  62  in the first passage  46  and second passage  48  allow the sensor  62  to take pressure readings on both sides of the valve  50 . Furthermore, the sensor  62  can take readings with minimal intrusion into the flow path of the valve  50 . 
     The valve stem  52  is connected to the solenoid  38  which acts on the valve stem  52  to move the valve member  54  between the open and closed position, or any other desired position therebetween, with respect to the valve seat  56 . The amount of space created by the valve member  54  and the valve seat  56  when the valve member  54  is displaced from the valve seat  56  is referred to as an effective orifice  64 . The effective orifice  64  is the amount of area available for the exhaust gas to flow through when it is flowing between the valve member  54  and the valve seat  56 . This effective orifice  64  creates a restriction of exhaust gas flow, and a pressure drop across the valve member  54  and the valve seat  56 . The size of the effective orifice  64  will vary, depending upon the position of the valve member  54  in relation to the valve seat  56 . The size of the effective orifice  64  can range from zero, when the valve  50  is closed, to a size equal to or greater than the size of the valve seat  56 , when the valve is fully open. 
     The actuator  38  also includes a position sensor  66  which provides a signal to the ECU  36  indicating the position of the valve member  54 . This allows the ECU  36  to compare the position of the valve  50  and the pressure across the valve  50  simultaneously. It is not required that a position sensor  66  be used in order to determine the appropriate position of the valve  50 . Rather the data collected by the sensor  62  can be enough for the ECU  36  to make a determination of how the valve  50  needs to be adjusted. 
     The embodiment shown in  FIG. 2  also shows a wiring harness  68  which is used to connect the sensor  62  to the ECU  36 . However, the embodiment in  FIG. 2  includes the concept of having the sensor  62  having an alternate connection  70 , which would allow the sensor  62  to be included in the connector  72 . Having the single connector  72  for both the solenoid  38  and the sensor  62  simplifies the invention even further. 
     The actuator  38  shown in the present embodiment of the invention is a solenoid. It is within the scope of this invention for virtually any other type of actuator to be used that will cause the desired controlled movement of the valve  50  in response to the signal from the sensor  62 , and if applicable, the position sensor  66 . Examples of other types of actuators  38  include, but are not limited to, D.C. motors, stepper motors, pneumatic actuators, hydraulic actuators or combinations thereof. The type of control signal generated by the ECU  36  to the actuator will depend on the type of actuator being used. For example, the control signal can be a stepped electrical pulse, an amplitude modulated signal, a pulse width modulated signal, or other electronic signals. 
     When the system  10  and valve  50  shown in  FIGS. 1-2  are operated, fresh air is fed into the intake pipe  24  and is compressed by the compressor  22 , and fed into the intercooler  26 . The air is then cooled by the intercooler  26 , and flows through the throttle valve  28 , through the intake manifold  14 , and into the engine  12 . The amount of air which flows into the intake manifold  14  is controlled by the throttle valve  28 . 
     The compressor  22  is powered by the turbine  20 . Once the fresh air is received by the engine  12  is combined with fuel, compressed, combusted and converted to exhaust gas. The turbine  20  receives the exhaust gas from the exhaust manifold  16 , and the energy from the exhaust gas is used to power the turbine  20 . That power is transferred to the compressor  22 , where the compressor compresses fresh air. 
     A portion of the exhaust gas does not flow to the turbine  20 . Some of the exhaust gas is recirculated back into the intake manifold and is fed into the engine  12 . This portion of exhaust gas will flow from the exhaust manifold  16  into the first conduit  32  and into the EGR valve  30 . Once the gas flows through the EGR valve  30 , it will flow into the second conduit  34 , and into the intake manifold  14 . 
     The EGR valve  30  controls the amount of exhaust gas that is recirculated from the exhaust manifold  16  to the intake manifold  14 . The EGR valve  30  and the throttle valve  28  are both controlled by the vehicle&#39;s ECU  36 . The ECU  36  controls the amount of fresh air going into the intake manifold  14  through the use of the throttle valve  28 , and also controls the amount of exhaust gas which is recirculated through the use of the EGR valve  30 . The sensor  62  measures a characteristic in proximity to the valve  50  relative to the valve position and flow. The sensor  62  as shown in  FIG. 2  is a pressure, sensor that measures pressure at the first side  58  and second side  60  of the valve  50 . The sensor  62  then transmits a signal to the ECU  36 . Using the information from the signal the ECU  36  determines whether the valve  50  needs to change position or be maintained. The desired position of the valve  50  is achieved by the ECU  36  adjusting the control signal to the actuator  38 . 
     It should be noted that the characteristic measured is not necessarily limited to pressure; the characteristic could also be mass flow rate, volumetric flow rate, temperature, air particulate content, contamination, density, or any other type of characteristic which can be used to provide an indication of gas flow. The sensor  62  could be any type of sensor used to measure the specific characteristics listed above on the first side  58  and the second side  60  of the valve seat  56 . 
     The pressure drop can be used to calculate the amount of exhaust gas flowing through the effective orifice  64 . The sensor  62  will then provide a signal to the ECU  36 ; the ECU  36  will then determine if the valve  50  position and control signal must change to achieve the desired exhaust gas flow through EGR valve  30 . In this embodiment, ECU  36  is programmed with a map of engine  12  operating conditions, or a set of predetermined operating conditions for the valve  50 , and a desired exhaust gas flow for each condition. There is an associated EGR valve  30  control signal and sensor  62  signal for each level of exhaust gas flow. The ECU  36  will receive the pressure inputs from the sensor  62  and the position sensor  66 , and determine the control signal required to achieve the desired position of valve  50  in EGR valve  30 , and provide the required amount of exhaust gas flow. The ECU  36  will adjust the position of the valve  50  to achieve or maintain the proper amount of exhaust gas flow through the EGR valve  30 . 
     Another embodiment of the present invention is shown in  FIG. 3  which includes a separate sensor  74  used to determine the exhaust gas pressure in the intake manifold  14  and ascend side  60  of valve seat  56 . The sensor  62  will then determine the level of pressure on the first side  58  of the valve seat  56 . The pressure measurement taken by the sensor  62  and the separate sensor  74  can also provide an indication of pressure differential, and therefore determine the amount of exhaust gas flow. 
     Another embodiment of the present invention is shown in phantom in  FIG. 1 . In this embodiment, the first conduit  32  is connected to the turbine  20 , instead of the exhaust manifold  16 , and the second conduit  34  is connected to the inlet pipe  24  of the compressor  22 . In this mode of operation, the EGR valve  30  is a “low-pressure” valve, because it is located downstream from the turbine  20 , and upstream from the compressor  22 . After the exhaust gas flows through the turbine  20 , the exhaust gas will flow through the first conduit  32 , and if the EGR valve  30  is open, the exhaust gas will flow through the EGR valve  30 , through the second conduit  34 , and into the inlet pipe  24 . If the EGR valve  30  is closed, the exhaust gas in the first conduit  32  will flow out of an outlet pipe  76 . 
     The present invention has the advantage of measuring exhaust gas flow and adjusting the size of the effective orifice  64  accordingly to ensure the exhaust gas flow is correct for each of the engine operating conditions. This presents a significant advantage over EGR systems which use a set of predetermined valve positions for each engine operating parameter which do not take into account contamination, wear, assembly tolerances, and other external factors which can affect the flow of exhaust gas through the valve  50 . These types of EGR valves infer flow from the position of the valve. The present invention has the distinct advantage of taking an actual measurement of gas pressure, and adjusting the flow of the gas to compensate for contamination, wear, assembly tolerances, and other factors affecting the flow of the gas. Essentially, the ECU  36  is using feedback from the sensor  62  and position sensor  66  to ensure there is optimal exhaust gas flow for each engine operating condition. 
     It should be noted that the position sensor  66  can be eliminated if necessary to suit a specific application. The sensor  62  can be used to provide feedback to the ECU  36 , and the ECU  36  will adjust the position of the valve  50  until the proper amount of exhaust gas flow is achieved. The actuator could also be a hydraulic actuator (not shown) where hydraulic pressure would be used to actuate the valve  50 . 
     In addition to the sensor  62  being physically integrated into the EGR valve  30 , the sensor  62  can also be electrically integrated in that there can be a single electrical connector which can be used for both the EGR valve  30  and the sensor  62 . 
     The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.