Abstract:
A fuel contaminant sensor is provided. The fuel containment sensor includes a fluid reservoir having an inlet and an outlet. A light source for projecting a light beam through the fluid reservoir is disposed on the fluid reservoir. A light beam detector for receiving the light beam projected through the fluid reservoir is disposed opposite the light source. A controller is provided for activating the light source and for receiving an output of the light beam detector. An interruption of the light beam inhibits the light beam detector from receiving the light beam.

Description:
FIELD 
       [0001]    The present disclosure relates to contaminant sensing, and more particularly to a fuel contaminant light sensor. 
       BACKGROUND 
       [0002]    The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art. 
         [0003]    Diesel engine fuel systems are sensitive to the presence of water and other contaminants in the diesel fuel. Since water does not provide the lubricity required for the tight fitting components of the diesel engine fuel system, the presence of water in the diesel fuel can cause wear on the components. In addition, water often contains biological and chemical corrosives that can cause degradation of the diesel fuel system components. As such, many diesel fuel systems use fuel-water separators to remove water and other contaminants from the diesel fuel. 
         [0004]    Fuel-water separators are typically coupled to a fuel line between the source of the diesel fuel and the engine. Fuel-water separators typically include a reservoir that collects the water and other contaminants after they have been separated from the diesel fuel. While these fuel-water separators work well for their intended purpose, the reservoir needs to be interrogated to determine if the volume of captured water is such that it needs to be drained and serviced. One form of interrogation known in the art is periodic visual inspection through the optically clear reservoir of the fuel-water separator. 
         [0005]    In recent years, electrically based sensors using electrodes have been added to the fuel-water separators to trigger a warning signal indicating that the reservoir needs to be drained. An electric potential is impressed upon these electrodes which is not conducted through the electrically non-conductive diesel fuel. However, when electrically conductive water is present, the electric potential is conducted through the water, thereby indicating the reservoir needs draining. While these electric sensors have worked well in the past, the electrodes of the electric sensors are possibly subject to some of the corrosive elements within the diesel and fuel contaminants. Therefore, there is room in the art for an improved non-conductive water sensing system. 
       SUMMARY 
       [0006]    In one aspect of the present invention a fuel contaminant light sensor is provided. 
         [0007]    In another aspect of the present invention the light sensor includes a fluid reservoir having an inlet and an outlet, a light source for projecting a light beam through the fluid reservoir, a light beam detector for receiving the light beam projected through the fluid reservoir, and a controller for activating the light source and receiving an output of the light beam detector. An interruption of the light beam inhibits the light beam detector from receiving the light beam. 
         [0008]    In still another aspect of the present invention the interruption is due to a change of an index of refraction of a fluid between the light source and the receiver. 
         [0009]    In still another aspect of the present invention the interruption is due to a change of index of refraction due to the introduction of a second fluid within the reservoir between the light source and the receiver. 
         [0010]    In still another aspect of the present invention the second fluid has an index of refraction different than an index of refraction of the first fluid. 
         [0011]    In still another aspect of the present invention the first fluid and the second fluid define an interface between the first fluid and the second fluid. 
         [0012]    In still another aspect of the present invention the light beam is refracted when the interface is disposed above the receiver and below the light source. 
         [0013]    In still another aspect of the present invention the interruption is due to droplets of a second fluid passing across the path of the light beam. 
         [0014]    In still another aspect of the present invention the light source is positioned near a top of the reservoir and the detector is positioned near a bottom of the reservoir. 
         [0015]    In still another aspect of the present invention the light source pulses the light beam. 
         [0016]    In still another aspect of the present invention the light source continuously emits the light beam. 
         [0017]    In still another aspect of the present invention the light source is a laser. 
         [0018]    In still another aspect of the present invention the light source is a light emitting diode. 
         [0019]    In a second aspect of the present invention a device for detecting a change in the contents of a fuel-water separator is provided. 
         [0020]    In another aspect of the present invention the device includes a fluid reservoir for containing a fluid, an emitter/detector coupled to the reservoir for emitting a light beam through the fluid and for detecting the light beam, a controller in electronic communication with the emitter/detector. The controller is operable to activate the emitter/detector to emit the light beam and operable to determine whether the light beam has been detected. A reflector is coupled to the reservoir. The reflector is in alignment with the emitter/detector such that the light beam emitted from the emitter is reflected by the reflector back to the emitter/detector. An interruption of the light beam between the emitter/detector and the reflector prevents the emitter/detector from detecting the light beam. 
         [0021]    In still another aspect of the present invention, the interruption is due to a change of index of refraction due to the introduction of a second fluid within the reservoir between the emitter/detector and the reflector. 
         [0022]    In still another aspect of the present invention the second fluid has an index of refraction different than an index of refraction of the first fluid. 
         [0023]    In still another aspect of the present invention the first fluid and the second fluid define an interface therebetween. 
         [0024]    In still another aspect of the present invention the interface refracts the light when the interface is disposed above the reflector and below the emitter/detector. 
         [0025]    In still another aspect of the present invention the interruption is due to a change of index of refraction in the fluid. 
         [0026]    In still another aspect of the present invention the interruption is due to droplets of a second fluid passing across the path of the light beam. 
         [0027]    In still another aspect of the present invention the emitter/detector pulses the light beam. 
         [0028]    In still another aspect of the present invention the emitter/detector continuously emits the light beam. 
         [0029]    In still another aspect of the present invention the emitter/detector includes a laser. 
         [0030]    In still another aspect of the present invention the emitter/detector includes a light emitting diode. 
         [0031]    Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
     
    
     
       DRAWINGS 
         [0032]    The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
           [0033]      FIG. 1A  is a schematic view of a fuel-water separator having a first embodiment of a water sensing system according to the principles of the present invention; 
           [0034]      FIG. 1B  is a schematic view of a fuel-water separator having the first embodiment of the water sensing system of the present invention with water present in the fuel-water separator; 
           [0035]      FIG. 2A  is a schematic view of a fuel-water separator having a second embodiment of the water sensing system according to the principles of the present invention; and 
           [0036]      FIG. 2B  is a schematic view of a fuel-water separator having the second embodiment of the water sensing system of the present invention with water present in the fuel-water separator. 
       
    
    
     DETAILED DESCRIPTION 
       [0037]    The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. 
         [0038]      FIG. 1A  illustrates a sensing system  10  according to the principles of the present invention. The sensing system  10  is illustrated in operation with an exemplary fuel-water separator  12 . However, it should be appreciated that the sensing system  10  may be employed with any structure having a reservoir for containing a substance, such as a fuel tank or storage container. The fuel-water separator  12  is typically located between a fuel supply (not shown) and an engine (not shown) of a motor vehicle (not shown). The fuel-water separator  12  is operable to separate water and other contaminates from fuel, as will be described in further detail below. The fuel-water separator  12  generally includes a ported housing  14  and a cup-shaped reservoir  16 . The housing  14  includes an inlet port  18  for receiving a fuel from the fuel supply (not shown) and an outlet port  20  for discharging the fuel once water and contaminates have been removed. The housing  14  further includes a fuel discharge port  22  and a fuel return port  24  located on a bottom surface  26  of the housing  14 . The reservoir  16  is sealingly secured to the bottom surface  26  such that the fuel discharge port  22  and fuel return port  24  are located within a cavity  28  defined by the reservoir  16  and the housing  14 . 
         [0039]    During operation of the fuel-water separator  12 , fuel from the fuel supply (not shown) enters the housing  14  via the inlet port  18 . The fuel passes through a flow passage (not shown) within the housing  14  and is discharged into the reservoir  16  via the fuel discharge port  22 , as indicated by the downward arrow. Water and contaminants, which are heavier than the fuel, settle to a quiet zone  30  located at the bottom of the reservoir  16 . The fuel then returns to the housing  14  via the fuel return port  24 , as indicated by the upward arrow. The fuel may then be further filtered within the housing  14  before being discharged from the fuel-water separator  12  via the outlet port  20 . To remove water or contaminants from the quiet zone  30 , the fuel-water separator  12  includes a drain valve  32  located at the bottom of the reservoir  16 . The drain valve  32  communicates between the reservoir and the surrounding environment. Opening the drain valve  32  allows the contents of the reservoir  16  to be discharged therefrom. 
         [0040]    The sensing system  10  includes a controller  34  in electronic communication with an emitter  36 , or light source, and a receiver  38 . In an alternate embodiment, the controller  34  is in electronic communication with the drain valve  32  in order to automatically open or close the drain valve  32 . The controller  34  is an electronic device having a preprogrammed digital computer or processor, control logic, memory used to store data, and at least one I/O section. The control logic includes a plurality of logic routines for monitoring, manipulating, and generating data. The controller  34  may be part of the control for a motor vehicle or a separate module. 
         [0041]    The emitter  36  is secured to the reservoir  16 , as will be described in further detail below. The emitter  36  is operable to emit a light beam therefrom. The light beam is indicated by the arrow “A” in  FIG. 1A  and may be coherent light or any other form of light. The emitter  36  may be any kind of light source, such as, for example, a laser or light emitting diode. The emitter  36  may emit the light beam continuously or it may pulse the light beam at predetermined or random intervals for selected time periods. The receiver  38  is also secured to the reservoir  16  and is located generally opposite the emitter  36 . The receiver  38  is operable to detect the light beam emitted from the emitter  36 . In the preferred embodiment, the emitter  36  and receiver  38  are protected by a layer or coating of non-corrosive materials, such as, for example, glass. 
         [0042]    In the particular example provided, the emitter  36  and the receiver  38  are coupled to an inner surface  40  of the reservoir  16 . Alternatively, the emitter  36  and the receiver  38  may be coupled to an outer surface  42  of the reservoir  16  so long as the emitter  36  is able to emit the light beam through the reservoir  16 . This may be accomplished by employing a transparent reservoir  16  made from a material having a known index of refraction or by providing ports through the reservoir  16  for the emitter  36  and receiver  38  to extend therethrough. 
         [0043]    The emitter  36  and receiver  38  are positioned within the reservoir  16  such that the light beam is directed from the emitter  36  towards the receiver  38 . So long as any substance, such as fuel or air, located within the cavity  28  has a constant index of refraction, the light beam emitted from the emitter  36  will be detected by the receiver  38 . 
         [0044]    The controller  34  communicates with the emitter  36  to activate the light beam and communicates with the receiver  38  to determine whether the light beam has been detected by the receiver  38 . If the light beam is directed from the emitter  36  to the receiver  38  without interruption, then the receiver  38  will communicate with the controller  34  that the receiver  38  is detecting the coherent light beam. This detection of the light beam is indicative that there is no interruption of the light beam, indicative that there is no change of index of refraction of the fuel within the cavity  28  of the fuel-water separator  12  and indicative that the reservoir  16  does not need to be drained of water or contaminants. 
         [0045]    in an alternate embodiment the sensing system  10  includes a plurality of receivers  39  located on the reservoir  16  opposite the emitter  36 . Alternatively, the receivers  38  and  39  may form one single strip sensor that extends along the reservoir  16 . The plurality of receivers  39  are in electronic communication with the controller  34 . Like the receiver  38 , the additional plurality of receivers  39  are operable to communicate with the controller  34  that the plurality of receivers  39  are detecting the light beam. As will be described in greater detail below, the plurality of receivers  39  will only detect the light beam when the light beam has been redirected within the reservoir  16 . 
         [0046]    Turning now to  FIG. 1B , if water is contained within the fuel as it enters the fuel-water separator  12 , this water will settle to the quiet zone  30  of the reservoir  16  where the water will accumulate, as indicated by reference number  44 . The water  44  in part defines an interface  46  between the water  44  and any other substance, such as fuel or air, within the cavity  28 . While water  44  is illustrated in the particular example provided, it should be appreciated that various other contaminants may separate out of the fuel and behave in the same manner as the water  44 . 
         [0047]    As the amount of collected water  44  increases, the interface  46  of the water  44  will rise towards the bottom surface  26  of the housing  12 . Eventually, the interface  46  of the water  44  will rise above the receiver  38  within the reservoir  16 , as is illustrated in  FIG. 1B . Once the interface  46  of the water  44  has risen above the receiver  38 , the water  44  will be in a direct line with the light beam emitted from the emitter  36 . As the light beam passes through the interface  46  of the water  44 , the light beam is refracted such that the light beam is no longer directed towards the receiver  38 . This refraction of the light beam occurs because the water  44  has an index of refraction different from the index of refraction of the fuel or air located within the cavity  28 . For example, the fuel within the cavity  28  has an index of refraction of approximately 1.44 while the water  44  has an index of refraction of approximately 1.33. The position of the receiver  38  with respect to the reservoir  16  determines how much water  44  is allowed to accumulate before the light beam is refracted. In the example illustrated in  FIGS. 1A and 1B , the receiver  38  is located near the bottom of the reservoir  16  such that a small amount of water  44  within the reservoir  16  will refract the coherent light beam. Alternatively, the receiver  38  may be positioned on the reservoir  16  closer to the bottom surface  26  of the housing  14  to allow more water  44  to accumulate before the water  44  refracts the light beam. In this sense, knowing the location of the receiver  38  relative to the reservoir  16  allows the sensing system  10  to know how much water has collected in the reservoir  16 . 
         [0048]    The light beam also may be attenuated if there is a change in the transparency of the substance within the cavity  28 . For example, if the fuel suffers from gelling or clouding due to cold weather, the transparency of the fuel will change, and the light beam will be attenuated such that it is not detected by the receiver  38 . Additionally, refraction may occur when water droplets falling from the top of the reservoir  16  to the quiet zone  30  momentarily interrupt the coherent light beam. Such momentary interruption of detection by the receiver  38  may be used to indicate early warning accumulation of water  44  within the reservoir  16 . 
         [0049]    As noted above, the controller  34  communicates with the emitter  36  to activate the light beam and communicates with the receiver  38  to determine whether the light beam has been detected by the receiver  38 . If the presence of the water  44  within the reservoir  16  refracts the light beam, the receiver  38  will communicate with the controller  34  that the receiver  38  is not detecting the light beam. This non-detection of the light beam is indicative of a problem within the fuel-water separator  12 . This problem may be that the water  44  within the reservoir  16  should be drained by opening the drain valve  32  or that the fuel is gelling or clouding due to cold weather. Once a problem has been detected, the controller  34  may take various initiatives to alert an operator of the motor vehicle of the problem or to take action to solve the problem. For example, the controller  34  may activate a water warning signal (either digital or analog), send an electronic signal to the motor vehicle control to activate a engine warning signal, automatically open the drain valve  32  using an electronically controlled actuator, or automatically activate a heating element to warm the fuel. 
         [0050]    In the embodiment where the sensing system  10  includes the plurality of receivers  39 , refraction or attenuation of the light beam can direct the light beam towards one of the plurality of receivers  39 . The plurality of receivers  39  then detects the light beam and communicates the detection to the controller  34 . Control logic within the controller  34  can use the detection of the light beam from a specific one of the plurality of receivers  39  to determine various conditions within the reservoir  16 . For example, the controller  34  may include a look-up table of known indices of refraction for known substances that are often additives of Diesel fuel such as kerosene or biodiesel fuel. As one of the plurality of receivers  39  detects the light beam, the controller  34  may calculate the index of refraction of the substance within the reservoir  16  based on which receiver  39  has detected the light, and use this calculated index of retraction to look up which substance has a matching index of refraction. In this way, the sensing system  10  can determine not only that there has been an interruption of the light beam, but it can also determine what kind of substance is located within the reservoir  16 . This may include what kind of fuel is being employed (such as what percentage of biodiesel fuel, kerosene, etc.) or what kind of contaminants are in the reservoir  16  (such as water, sea water, etc.). The use of the plurality of sensors  39  may also be used to determine the water level or contamination level within the reservoir  16  based on the degree of the calculated index of refraction. The controller  34  is operable to track the change in the index of refraction of the fuel within the reservoir  16  over a period of time. The controller  34  may then communicate the determined composition of the fuel to an engine controller (not shown) which can then use the information to adjust combustion parameters. 
         [0051]    With reference to  FIG. 2 , a second sensing system  100  is illustrated with the exemplary fuel-water separator  12 . The second sensing system  100  includes a controller  102  in electronic communication with an integrated light emitter/detector  104 . A reflector  106  is positioned opposite the integrated light emitter/detector  104 . The controller  102  is an electronic device having a preprogrammed digital computer or processor, control logic, memory used to store data, and at least one I/O section. The control logic includes a plurality of logic routines for monitoring, manipulating, and generating data. The controller  102  may be part of the control for a motor vehicle or a separate module. 
         [0052]    The integrated light emitter/detector  104  is coupled to the reservoir  16 , as will be described in further detail below. The integrated light emitter/detector  104  is operable to emit a light beam therefrom and is operable to detect a returning light beam. The light beam is indicated by the arrow “A” in  FIG. 2A . The integrated light emitter/detector  104  may be any kind of light source and light detector known in the art. The integrated light emitter/detector  104  may emit the light beam continuously or the integrated light emitter/detector  104  may pulse the light beam at predetermined or random intervals. The reflector  106  is also coupled to the reservoir  16  and is located generally opposite the emitter  36 . The reflector  106  has a surface  108  operable to reflect the light beam back towards the integrated light emitter/detector  104 . In the preferred embodiment, the integrated light emitter/detector  104  and the reflector  106  are protected by a coating or layer of a non-corrosive material, such as, for example, glass. 
         [0053]    In the particular example provided, the integrated light emitter/detector  104  and reflector  106  are coupled to an inner surface  40  of the reservoir  16 . Alternatively, the integrated light emitter/detector  104  and the reflector  106  may be coupled to an outer surface  42  of the reservoir  16  so long as the integrated light emitter/detector  104  is able to emit the light beam through the reservoir  16 . This may be accomplished by employing a transparent reservoir  16  made from a material having a known index of retraction or by providing ports through the reservoir  16  for the integrated light emitter/detector  104  and the reflector  106  to extend therethrough. 
         [0054]    The integrated light emitter/detector  104  and the reflector  106  are positioned within the reservoir  16  such that the light beam is directed from the integrated light emitter/detector  104  towards the reflector  106  which in turn reflects the light beam back towards the integrated light emitter/detector  104 . So long as any substance, such as fuel or air, located within the cavity  28  has a constant index of refraction, the light beam emitted from the integrated light emitter/detector  104  will be reflected by the reflector  106  and in turn detected by the integrated light emitter/detector  104 . 
         [0055]    The controller  102  communicates with the integrated light emitter/detector  104  to activate the light beam and to determine whether the light beam has been in turn detected by the integrated light emitter/detector  104 . If the light beam is emitted and detected by the integrated light emitter/detector  104 , then the integrated light emitter/detector  104  will communicate with the controller  102  that the integrated light emitter/detector  104  is detecting the light beam. This detection of the light beam is indicative that there is no interruption of the light beam, indicative that there is no change of index of refraction of the fuel within the cavity  28  of the fuel-water separator  12  and indicative that the reservoir  16  does not need to be drained of water or contaminants. 
         [0056]    Turning now to  FIG. 2B , water  44  located within the reservoir  16  at a level above the reflector  106  has an effect similar to that described in  FIG. 1A . Specifically, as the amount of water  44  that is collected increases, the interface  46  of the water  44  will rise towards the bottom surface  26  of the housing  12 . Eventually, the interface  46  of the water  44  will rise above the reflector  106  within the reservoir  16 . Once the interface  46  of the water  44  has risen above the reflector  106 , the water  44  will be in direct line with the light beam emitted from the integrated light emitter/detector  104 . As the light beam passes across the interface  46  of the water  44 , the light beam is refracted such that the light beam is no longer directed towards the receiver  38 . This refraction of the light beam occurs because the water  44  has an index of refraction different from the index of refraction of the fuel or air located within the cavity  28 . The position of the reflector  106  with respect to the reservoir  16  determines how much water  44  is allowed to accumulate before the light beam is refracted. 
         [0057]    The light beam also may be attenuated if there is a change in the transparency of the substance within the cavity  28 . For example, if the fuel suffers from gelling or clouding due to cold weather, the transparency of the fuel will change, and the light beam will be attenuated such that it is not detected by the integrated light emitter/detector  104 . 
         [0058]    As noted above, the controller  102  communicates with the integrated light emitter/detector  104  to activate the light beam and to determine whether the light beam has been detected. If the presence of the water  44  within the reservoir  16  refracts the light beam, the integrated light emitter/detector  104  will communicate with the controller  102  that the integrated light emitter/detector  104  is not detecting the light beam. This non-detection of the light beam is indicative of a problem within the fuel-water separator  12 . This problem may be that the water  44  within the reservoir  16  should be drained by opening the drain valve  32  or that the fuel is gelling or clouding due to cold weather. Once a problem has been detected, the controller  102  may take various initiatives to alert an operator of the motor vehicle of the problem or to take action to solve the problem. For example, the controller  102  may activate a water warning signal (either digital or analog), send an electronic signal to the motor vehicle control to activate a engine warning signal, automatically open the drain valve  32  using an electronically controller actuator, or automatically activate a heating element to heat the fuel. 
         [0059]    The description of the invention is merely exemplary in nature and 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.