Abstract:
A customizable low fuel indicator system for a motor vehicle having an engine control unit storing the average fuel economy of the motor vehicle. A fuel tank sensor is in electronic communication with the engine control unit and is adapted to sense the amount of fuel remaining in a fuel tank of the motor vehicle. An indicator is in electronic communication with the engine control unit. An input device is in communication with the electronic control unit for selecting a threshold distance to empty. The engine control unit calculates a distance to empty value based on the average fuel economy and the amount of fuel sensed by the fuel tank sensor. The indicator is activated by the engine control unit when the distance to empty is less than the threshold distance to empty.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to a low fuel indicator system and more particularly to a low fuel indicator system that is customizable.  
       BACKGROUND OF THE INVENTION  
       [0002]     Running out of fuel while driving a motor vehicle is a common occurrence. The essential problem is that many drivers inadvertently forget to observe when the fuel level gauge has reached the “empty” position. And even then it can occur when the driver is unaware how far the motor vehicle can travel at any given position of the fuel gauge, and the motor vehicle runs out of fuel between service stations.  
         [0003]     To combat this issue, many motor vehicles are equipped with a fuel warning indicator that notifies the driver of the motor vehicle, typically with a light or sound, that the fuel tank is running low. While this solution has worked very satisfactorily, there is still room for improvement.  
         [0004]     The distance a motor vehicle can travel without stopping to refill the fuel tank is dependent on the amount of fuel within the tank and the fuel economy of the motor vehicle. In order to calculate when an indicator should be activated, the typical fuel warning indicator uses an estimated fuel economy based on the type and class of the particular motor vehicle. However, this estimation does not take into account the actual fuel economy of the motor vehicle, which can be dependent on how and where the motor vehicle is driven. Moreover, the point in time at which the typical fuel warning indicator is activated is set by the manufacturer, and may be any particular distance to empty.  
       SUMMARY OF THE INVENTION  
       [0005]     A customizable low fuel indicator system for a motor vehicle includes an engine control unit storing the average fuel economy of the motor vehicle. A fuel tank sensor is in electronic communication with the engine control unit and is adapted to sense the amount of fuel remaining in a fuel tank of the motor vehicle. An indicator is in electronic communication with the engine control unit. An input device is in communication with the electronic control unit for selecting a threshold distance to empty. The engine control unit calculates a distance to empty value based on the average fuel economy and the amount of fuel sensed by the fuel tank sensor. The indicator is activated by the engine control unit when the distance to empty is less than the threshold distance to empty.  
         [0006]     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  
       [0007]     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:  
         [0008]      FIG. 1  is a schematic illustration of a motor vehicle having a low fuel indicator system constructed according to the principles of the present invention;  
         [0009]      FIG. 2  is a schematic diagram of the control system for the low fuel indicator system of  FIG. 1 ; and  
         [0010]      FIG. 3  is a flowchart illustrating a methodology for customizing the low fuel indicator system of claim  1 . 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0011]     Referring to  FIG. 1  of the drawings, a motor vehicle  8  is illustrated having a low fuel indicator system  10  constructed according to the principles of the present invention. Those skilled in the art will appreciate that the incorporation of the low fuel indicator system  10  into the motor vehicle  8  is merely exemplary in nature and that the low fuel indicator system  10  has applicability to various other environments, for example motor boats or aircraft.  
         [0012]     The low fuel indicator system  10  generally includes an engine control unit  12 , a trip computer  14 , a visual indicator  16 , an audible indicator  18 , and a fuel tank sensor  20 . The engine control unit  12  is a centralized controller that essentially controls the electromechanical and electronic mechanisms of the motor vehicle  8  according to pre-programmed instructions and driver input. In this regard, the engine control unit  12  is in communication with the powertrain (not shown) of the motor vehicle  8  as well as the various other components of the low fuel indicator system  10 , as will be described below. Alternatively, the engine control unit  12  may be a body controller or any generic microprocessor controller.  
         [0013]     The trip computer  14  is mounted within the dashboard  20  of the motor vehicle  8  so as to be easily accessible by an occupant of the motor vehicle  8 . Alternatively, the trip computer  14  can be mounted within the roof (not shown) or center console (not shown) of the motor vehicle  8 . The trip computer  14  is a microprocessor that includes a display (not shown) and input controls (not shown) linked to a microprocessor (not shown).  
         [0014]     The visual indicator  16  is mounted within the dashboard  20  near the driver side of the motor vehicle  8  for indicating to the driver of the motor vehicle  8  when the fuel level is low. In the particular example provided, the indicator  20  is a light emitting diode (LED). However, various other light indicators may be employed, for example a candescent bulb.  
         [0015]     The audible indicator  18  is mounted within the dashboard  22  and also indicates to the driver of the motor vehicle  8  when the fuel level is low. Alternatively, the audible indicator  18  may be mounted within the trip computer  14 . The audible indicator  18  is preferably a conventional speaker that provides an audible sound, such as, for example, a bell sound. However, various other sound producing mechanisms and various other audible sounds may be employed.  
         [0016]     The fuel sensor  20  is mounted within a fuel tank  26  of the motor vehicle. The fuel sensor  20  senses the amount of fuel (not shown) within the fuel tank  26  using conventional means.  
         [0017]     Turning to  FIG. 2 , the control schematic for the low fuel indicator system  10  is provided. As can be seen, the trip computer  14  is in two way electronic communication with the engine control unit  12 . The microprocessor (not shown) within the trip computer  14  converts signals from the engine control unit  12  and displays them for the occupants. The microprocessor also converts input from the occupants into electronic signals and sends the signals to the engine control unit  12 . The visual and audible indicators  16 ,  18  are in electronic communication with the engine control unit  12  and are activated by an electronic signal from the engine control unit  12 . The fuel sensor  20  is in electronic communication with the engine control unit  12  and sends a signal to the engine control unit  12  providing the fuel level within the fuel tank  26 .  
         [0018]     With reference to  FIG. 3 , a method of customizing the low fuel indicator system  10  will now be described and is generally indicated by reference numeral  100 . The method  100  begins when the occupant or driver of the motor vehicle  8  sets a Threshold Distance To Empty (TDTE) in the trip computer  14 , shown at step  102 . The TDTE is essentially at what time the driver wishes to be notified that the fuel tank  26  is nearing empty. The TDTE is expressed as the distance the motor vehicle  8  can travel before the fuel tank  26  is empty. Crossing the TDTE, as will be described below, will activate the visual and audible indicators  16 ,  18  thereby notifying the driver that the fuel tank  24  is low. In this regard, the driver selects the TDTE to correspond to the distance the driver wishes to be able to travel after the driver has been warned by the visual and audible indicators  16 ,  18 . For example, if the driver wishes to be able to travel  60  miles after the visual indicator  16  has been activated, the driver may enter “60” as the TDTE (e.g. as the threshold distance).  
         [0019]     During operation of the motor vehicle, the engine control unit  12  calculates and stores the Average Fuel Economy of the motor vehicle  8  at step  104 . The Average Fuel Economy is an average over time of the distance traveled by the motor vehicle  8  per unit of consumed fuel. The Average Fuel Economy may be higher or lower depending on how and where the motor vehicle  8  is being driven (e.g. fast acceleration typically provides a lower Average Fuel Economy than slow acceleration, and driving on a highway provides a typically higher Average Fuel Economy than driving on a surface road).  
         [0020]     The fuel sensor  20  next senses the amount of fuel within the fuel tank  26  at step  106 . This information is submitted to the engine control unit  12 . It should be noted that while step  106  is illustrated as being dependent on step  104 , sensing the fuel is a continuous process that occurs simultaneously with other steps.  
         [0021]     The engine control unit  12  then calculates a Distance To Empty (DTE) at step  108 . The DTE is the calculated distance the motor vehicle  8  can be expected to travel before the fuel tank  26  is empty. The DTE is calculated using the current amount of fuel in the fuel tank  26  using the fuel sensor  20  at step  106 . The Average Fuel Economy is then used to estimate the DTE. By taking into account the unique Average Fuel Economy of the motor vehicle  8 , a more precise DTE can be calculated.  
         [0022]     The DTE is then compared to the TDTE at step  110 . If the DTE is greater than the TDTE (e.g. the motor vehicle  8  can travel farther than the distance the driver has selected as the threshold), then the method  100  proceeds to step  112 . At step  112 , if the visual indicator  16  is currently activated, then the visual indicator  16  is deactivated by the engine control unit  12  at step  114 . This corresponds to the situation wherein the visual indicator  16  has been activated due to low fuel in the fuel tank  26 , but due to a change in the fuel level (e.g. the tank has been filled) the DTE is no longer less than the TDTE. After the visual indicator  16  has been deactivated, the method  100  returns to step  104  and the method  100  repeats. At step  112 , if the visual indicator  16  was not active, then the method  100  also returns to step  104  and repeats.  
         [0023]     At step  110 , if the DTE is less than or equal to the TDTE (e.g. the distance the motor vehicle  8  can travel is less than the threshold distance selected by the driver), then the method proceeds to step  116 . At step  116 , if the visual indicator  16  is currently activated, then the method  100  returns to step  104  and repeats. This corresponds to the situation wherein the driver is already being notified that the threshold distance has been passed since the visual indicator  16  has already been activated.  
         [0024]     However, if at step  116  the visual indicator  16  is not currently activated, then at step  118  the engine control unit  12  activates the audible indicator  18  to indicate audibly that the threshold distance has been crossed. The audible indicator  18  is only activated once so as not to distract or harass the occupants of the motor vehicle  8 . Then, at step  120 , the visual indicator  16  is activated to further notify the driver that the motor vehicle  8  is low on fuel. The method  100  then returns to step  104  and repeats. The visual indicator  16  will stay activated until such time as the DTE of the motor vehicle  8  is greater than the TDTE.  
         [0025]     By allowing the driver to customize when the indicators  16 ,  22  are activated, the low fuel indicator system  10  provides greater driver satisfaction. Moreover, using the actual average fuel economy of the motor vehicle  8 , rather than an estimate, provides a more accurate estimation of the distance the motor vehicle  8  can travel before the fuel tank  22  is empty.  
         [0026]     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.