Abstract:
A fuel pump controller includes a detecting device for detecting environmental vibrational energy and converting the environmental vibrational energy into an electrical signal. A motor controller is coupled to a fuel pump motor wherein the electrical signal is used by the controller to command the fuel pump motor to operate at one of a plurality of speeds wherein the commanded speed is at least in part a function of the environmental vibrational energy.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 60/782,421, filed on Mar. 15, 2006. The disclosure of the above application is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     This application generally relates to vehicle fuel delivery systems and more particularly relates to control systems for variable speed fuel pumps. 
     BACKGROUND 
     Vehicle fuel pump systems commonly employ an electric motor coupled to a mechanical pump for pumping fuel from a fuel reservoir to an engine. Although it is possible to simplify the fuel system controls by operating the electric motor at a sufficiently high speed such that the pump will meet the greatest, fuel demand imposed by the engine, such a simplistic approach may degrade the fuel efficiency of the vehicle (by wasting electrical energy) and adversely effects the life expectancy of the components in the fuel delivery system. In order to operate a fuel delivery system as efficient as possible, it is common for the fuel control system to monitor one or more engine parameters indicative of the real time fuel demand of the engine. Under this controlled, approach, the fuel control system can operate the motor at slower speeds when the fuel demand of the engine is minimal or moderate and the control system can operate the pump motor at higher speeds when the fuel consumption demand of the engine is high. Although such control systems are effective for enhancing the efficiency and life expectancy of the components of the fuel delivery system, they require extra complexity, such as tying the fuel delivery system to the engine or engine control system. This complexity not only increases development costs, but it also increases the cost of implementing the system inasmuch as additional electrical conductors, connectors, and other components must be incorporated into the fuel delivery system. 
     The present invention provides, among other things, a variable speed motor coupled to a fuel pump, without requiring interconnection of the fuel system to the engine or engine control system for sensing the fuel demands of the engine. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagrammatic view of a vehicle employing an embodiment of the fuel pump speed control system of the present invention; 
         FIG. 2  is a diagrammatic view of an embodiment of the fuel pump speed control system of the present invention; 
         FIG. 3  is a graphical representation of an interaction between a signal derived from an environmental noise transducer and a road noise threshold level signal. 
     
    
    
     DETAILED DESCRIPTION 
     Now referring to  FIG. 1 , vehicle  10  employs engine  12  for propelling vehicle  10  and fuel system  14  for storing and pumping fuel from fuel tank  16  to engine  12  by way of fuel delivery conduit  18 . Although much of the description herein primarily focuses on the delivery of liquid fuels to engine  12 , nothing herein is meant to limit the present invention to liquid fuel delivery systems. Fuels in gaseous, or even semi-solid states could also be delivered using the present invention. 
     Fuel system  14  may use electric power provided from power source  20  (typically a battery or the like), to provide electrical operating power to motor  22  and to the electrical components (motor controller  24 , signal conditioning module  26 , and possibly environmental noise transducer  28 ) used to control the speed of motor  22 . Fuel pump  32  and motor  22  may be packaged together  30  and reside within a fuel storage cavity of fuel tank  16 . Although this packaging methodology is common, nothing in the present invention is limited to only this packaging convention and the present invention may be used in systems where only one of the pump  32  or the motor  22  resides within the fuel storage cavity of the fuel tank  16 . It is also possible to locate both the fuel pump  30  and the motor  22  outside of the fuel tank  16  and rely on gravity or other means (such as a pump vacuum) to deliver the fuel from fuel tank  16  to pump  32 . 
     Motor controller  24 , signal conditioning module  26 , and, if included, an environmental noise transducer  28 , can reside in any portion of the vehicle and still function to carry out an embodiment of the present invention. However, for many embodiments, it may be advantageous to fit all three components (motor controller  24 , signal conditioning module  26 , and environmental noise transducer  28 ) within a single connector housing  34  which may, in turn, function as an electrical connector to mate with a receiving/mating electrical connector  36 . Connector  36  conveys appropriate electrical signals from connector  34  to motor  22 . By integrating motor controller  24 , signal conditioning module  26 , and, if present, an environmental noise transducer  28 , within a single connector housing  34 , most of the electrical components that comprise fuel system  14  are conveniently located in a single wiring connector  34 . This packaging approach not only minimizes the handling and inventorying of numerous, discrete components, it also minimizes electrical connections that would otherwise be exposed to environmental conditions that might eventually compromise the operation of motor controller  24 , signal conditioning module  26 , or environmental noise transducer  28 . 
     Now referring to  FIG. 1  and  FIG. 2 , connector  34  may include interface portion  38  which is adapted to receivingly mate with interface portion  40  of connector  36 . Interface  38  may carry all of the electrical conductors which are necessary for the operation of fuel pump and motor assembly  30 . Connector  34  includes, in an embodiment, an environmental transducer  28  for converting environmental noise or vibration to an electrical signal. Transducer  28 , in one embodiment, can be any type of detecting device for detecting environmental vibrational energy associated with a vehicle state, such as a microphone for picking up ambient, road noise associated with the vehicle as the vehicle traverses the road. In another embodiment, transducer  28  can include an accelerometer for picking up vehicle vibration imparted to an accelerometer during vehicle operation. In many instances, the combination of one or more engine noise, drivetrain noise, or road noise picked up by environmental noise transducer  28  can be used as an accurate proxy for engine fuel demand. Specifically, under many vehicle operating conditions, there is a positive correlation between environmental vibrational energy and fuel demand. Accordingly, in order to satisfy the fuel demands of engine  12  during a high fuel demand mode of operation, the signal generated by environmental noise transducer  28  can be sent directly to controller  24  as a means of measuring fuel demand. In some applications it may be advantageous to electronically condition the transducer  28  signal by way of a signal conditioning module  26  for filtering, amplifying, or the like prior to sending it to controller  24 . 
     The output  42  of motor controller  24  may be directly coupled to motor  22  (by way of connector  36 ) and it is used to control the speed of fuel pump motor  22 . Motor controller  24  may be of the type that employs pulse width modulation (hereinafter PWM) motor control. However, other motor control methodologies known to those skilled in the art may also be used to control the rotational speed of motor  22 . 
     Now referring to  FIG. 3 , the present invention can be implemented using any number of discrete speed settings for fuel pump and motor assembly  30 ; however, the present invention will now be discussed in the context of two discrete motor speed command settings. 
     In instances where the output signal of environmental noise transducer  28  (after it is conditioned by module  26 ) is below a preset noise threshold level (such as depicted at t 1  in  FIG. 3 ), the output  42  of motor controller  26  may be maintained at a first level (SP 1 ) such that fuel pump and motor assembly  30  rotate at a first speed which is sufficient to meet the low and moderate fuel demands of engine  12 . 
     In periods of operation when engine  12  is required to deliver more horsepower, the output signal from signal conditioning module  26  will cross (shown at t 2 ), and reside above preset road noise threshold level (see the time duration span between t 2  and t 3  in  FIG. 3 ). During the time when the output signal from signal conditioning module  26  is above preset road noise threshold level, the output signal generated by controller  24  is adjusted upward to a level indicated by SP 2 . The SP 2  level indicates a motor speed command that is greater than that commanded at the SP 1  level. This increased command will cause fuel pump motor and pump assembly  30  to rotate at a higher speed enabling greater fuel volume rates to be delivered to engine  12 . Once the conditioned output signal from signal conditioning module  26  returns below the preset road noise threshold level (depicted by the cross over at t 3 ), motor controller  24 , once again, issues an output signal at the SP 1  signal at its output  42  thereby commanding fuel pump and motor assembly  30  to rotate at a slower speed (thereby conserving energy costs associated with running the fuel pump motor  30  at higher speeds). By following the control methodology of  FIG. 3 , the fuel pump will deliver fuel at a rate that is a function of (or is correlated to) engine demand. 
     Although the present invention has been discussed in the context of operating fuel pump motor and pump assembly  30  at two operational speeds (i.e. SP 1 , and SP 2 ), it is fully contemplated that three or more command speeds may be used for carrying out the invention and that improved efficiencies may be realized by using three or more motor speed command levels. Additionally, although an embodiment of the present invention has been discussed in the context of using discrete steps between motor speed command SP 1  and motor speed command SP 2 , it is contemplated that the differences between adjacent, discrete steps can be made infinitesimally small such that the motor speed command achieved at output  42  allows infinitely variable (or near infinitely variable) speed adjustment for fuel pump motor and pump assembly  30 . 
     Having described various embodiments of the present, invention, it will be understood that various modifications or additions may be made to the embodiments illustrated herein without departing from the spirit of the present invention. For example, environmental transducer  28  has been disclosed herein in the form of a microphone, an accelerometer, or combinations of the two. However, it is contemplated that other types of environmental transducers can be used for carrying out the present invention. Accordingly, it is to be understood that the subject, matter sought to be afforded protection hereby shall be deemed to extend to the subject matter defined in the appended claims, including all fair equivalents thereof.