Patent Publication Number: US-2016230720-A1

Title: Fluid Conditioning Module

Description:
TECHNICAL FIELD 
     This patent disclosure relates generally to fluid conditioning systems and, more particularly, to fuel conditioning modules for combustion engines. 
     Reciprocating internal combustion (IC) engines are known for converting chemical energy stored in a fuel supply into mechanical shaft power. A fuel-oxidizer mixture is received in a variable volume of an IC engine defined by a piston translating within a cylinder bore. The fuel-oxidizer mixture burns inside the variable volume to convert chemical energy from the mixture into heat. In turn, expansion of the combustion products within the variable volume performs work on the piston, which may be transferred to an output shaft of the IC engine. 
     Combustion engines may inject high pressure liquid fuel directly into the variable volume, and a liquid fuel delivery system may employ two or more fuel pumping stages in series to achieve the desired final injection pressure. For example, common rail fuel systems for direct injection compression ignition engines may include a fuel transfer pump that draws fuel from a fuel tank and delivers the fuel to the inlet of a high pressure common rail pump, which further increases the fuel pressure to the desired injection pressure. 
     Filters have been used to remove unwanted particulates, unwanted fluids (e.g., water), or both, from liquid fuel systems. For example, US Patent Publication No. US2004/0118764 (“the &#39;764 publication”) describes a multiple fuel filter pump module. The dual fuel filter pump module of the &#39;764 publication draws a flow of fuel from a fuel tank and delivers one portion of the fuel flow to an engine fuel supply line, and directs another portion of the fuel flow to the fuel tank via a regulator fuel line for re-circulation through the fuel system. Although the fuel system described in the &#39;764 publication may be used advantageously for some combustion engine applications, other fuel systems may be better tailored to meet the filtration performance and system packaging needs of other combustion engine applications. 
     Accordingly, there is a need for improved fuel systems to address the aforementioned concerns and/or other problems in the art. 
     SUMMARY 
     According to an aspect of the disclosure, a fluid conditioning system comprises a first filter mount having a first filter inlet port and a first filter outlet port; a first motor; a first pump operatively coupled to the first motor, an outlet of the first pump being fluidly coupled to the first filter inlet port via a first filter inlet conduit, an inlet of the first pump being fluidly coupled the first filter outlet port via a first filter outlet conduit; a second filter mount having a second filter inlet port; a second pump, an inlet of the second pump being fluidly coupled to the first filter outlet port via the first filter outlet conduit, an outlet of the second pump being fluidly coupled to the second filter inlet port via a second filter inlet conduit; and a controller operatively coupled to the first motor, the controller being configured to operate the first pump at a flowrate that is higher than a flowrate of the second pump. 
     According to another aspect of the disclosure, a fluid conditioning module comprises a block defining a first filter inlet port, a first filter outlet port, a second filter inlet port, and a second filter outlet port; a first pump fastened to the block, an outlet of the first pump being fluidly coupled to the first filter inlet port via a first filter inlet conduit defined by the block, an inlet of the first pump being fluidly coupled to the first filter outlet port via a first filter outlet conduit defined by the block; and a second pump fastened to the block, an outlet of the second pump being fluidly coupled to the second filter inlet port via a second filter inlet conduit defined by the block, an inlet of the second pump being fluidly coupled to the first filter outlet port via the first filter outlet conduit. 
     According to another aspect of the disclosure, a method for conditioning a fluid includes comprises pumping a fluid flow through a first pump; filtering the fluid flow through a first filter; recirculating a first portion of the fluid flow through the first filter via the first pump; pumping a second portion of the fluid flow through a second pump, the second portion of the fluid flow being less than the first portion of the fluid flow; and filtering the second portion of the fluid flow through a second filter. 
     According to another aspect of the disclosure, a fluid conditioning module comprises a block, a first pump fastened to the block, a second pump fastened to the block, a first filter removably coupled to the block, an inlet of the first filter being fluidly coupled to an outlet of the first pump via a first filter inlet conduit defined by the block, an outlet of the first filter being fluidly coupled to an inlet of the first pump via a first filter outlet conduit, and a second filter removably coupled to the block, an inlet of the second filter being fluidly coupled to an outlet of the second pump via a second filter inlet conduit defined by the block, an inlet of the second pump being fluidly coupled to the outlet of the first filter via the first filter outlet conduit. 
     According to another aspect of the disclosure, a fluid conditioning system comprises a first filter mount having a first filter inlet port and a first filter outlet port; a motor unit; a recirculation pump unit operatively coupled to the motor unit, an outlet of the recirculation pump unit being fluidly coupled to the first filter inlet port via a first filter inlet conduit, an inlet of the recirculation pump unit being fluidly coupled to the first filter outlet port via a first filter outlet conduit; a second filter mount having a second filter inlet port; and a delivery pump unit operatively coupled to the motor unit. The delivery pump unit includes a plurality of delivery pumps, an inlet of each delivery pump of the plurality of delivery pumps being fluidly coupled to an inlet of the delivery pump unit, and an outlet of each delivery pump of the plurality of delivery pumps being fluidly coupled to an outlet of the delivery pump unit. The inlet of the delivery pump unit is fluidly coupled to the first filter outlet port via the first filter outlet conduit, and the outlet of the delivery pump unit is fluidly coupled to the second filter inlet port via a second filter inlet conduit. 
     According to another aspect of the disclosure, a fluid conditioning module comprises a block defining a first filter inlet port, a first filter outlet port, a second filter inlet port, and a second filter outlet port; a recirculation pump unit fastened to the block, an outlet of the recirculation pump unit being fluidly coupled to the first filter inlet port via a first filter inlet conduit defined by the block, an inlet of the recirculation pump unit being fluidly coupled to the first filter outlet port via a first filter outlet conduit defined by the block; and a delivery pump unit fastened to the block. The delivery pump unit includes a plurality of delivery pumps, an inlet of each delivery pump of the plurality of delivery pumps being fluidly coupled to an inlet of the delivery pump unit, and an outlet of each delivery pump of the plurality of delivery pumps being fluidly coupled to an outlet of the delivery pump unit. The outlet of the delivery pump unit is fluidly coupled to the second filter inlet port via a second filter inlet conduit defined by the block, and the inlet of the delivery pump unit is fluidly coupled to the first filter outlet port via the first filter outlet conduit. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a side view of a machine, according to an aspect of the disclosure. 
         FIG. 2  shows a schematic view of a fuel supply system, according to an aspect of the disclosure. 
         FIG. 3  shows a schematic view of a fluid conditioning module, according to an aspect of the disclosure. 
         FIG. 4  shows a schematic view of a fluid conditioning module, according to an aspect of the disclosure. 
         FIG. 5  shows a perspective view of a fluid conditioning module, according to an aspect of the disclosure. 
         FIG. 6  shows a partial cross sectional view of the fluid conditioning module illustrated in  FIG. 5 , according to an aspect of the disclosure. 
         FIG. 7  shows a partial cross sectional view of the fluid conditioning module illustrated in  FIG. 5 , according to an aspect of the disclosure. 
         FIG. 8  shows a partial cross sectional view of the fluid conditioning module illustrated in  FIG. 5 , according to an aspect of the disclosure. 
         FIG. 9  shows a schematic view of a fluid conditioning module, according to an aspect of the disclosure. 
         FIG. 10  shows a schematic view of a delivery pump unit, according to an aspect of the disclosure. 
         FIG. 11  shows a schematic view of a delivery pump unit, according to an aspect of the disclosure. 
         FIG. 12  shows a schematic view of a motor unit, according to an aspect of the disclosure. 
         FIG. 13  shows a schematic view of a motor unit, according to an aspect of the disclosure. 
         FIG. 14  shows a schematic side view of a fluid conditioning module, according to an aspect of the disclosure. 
         FIG. 15  shows a schematic side view of a fluid conditioning module, according to an aspect of the disclosure. 
         FIG. 16  shows a schematic side view of a fluid conditioning module, according to an aspect of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Aspects of the disclosure will now be described in detail with reference to the drawings, wherein like reference numbers refer to like elements throughout, unless specified otherwise. 
       FIG. 1  shows a side view of a machine  100 , according to an aspect of the disclosure. The machine  100  includes an internal combustion (IC) engine  104  that is fluidly coupled to a fuel supply system  106 . The IC engine  104  maybe a reciprocating internal combustion engine, such as a compression ignition engine or a spark ignition engine, for example, or a rotating internal combustion engine, such as a gas turbine, for example. 
     The machine  100  may be propelled over a work surface  110  by wheels  112  coupled to a chassis  114 . The wheels  112  may be driven by motors  116 , a mechanical transmission coupled to the IC engine  104 , or combinations thereof. It will be appreciated that the machine  100  could also be propelled by tracks (not shown), combinations of wheels  112  and tracks, or any other surface propulsion device known in the art. Alternatively, the machine  100  could be a stationary machine, and therefore may not include a propulsion device. 
     The machine  100  may also include a work implement  118  driven by an actuator  120 . The work implement  118  could be a dump bed, a shovel, a drill, a fork lift, a feller-buncher, a conveyor, or any other implement known in the art for performing work on a load. The actuator  120  may be a hydraulic actuator, such as a linear hydraulic motor or a rotary hydraulic motor, an electric motor, a pneumatic actuator, or any other actuator known in the art. 
     The machine may include a cab  122  configured to accommodate an operator, and have a user interface  124  including using input devices for asserting control over the machine  100 . The user interface  124  may include pedals, wheels, joysticks, buttons, touch screens, combinations thereof, or any other user input device known in the art. Alternatively or additionally, the user interface  124  may include provisions for receiving control inputs remotely from the cab  122 , including wired or wireless telemetry, for example. The IC engine  104 , the fuel supply system  106 , and the user interface  124  may be operatively coupled to one another via a machine controller  130 . 
     The machine can be an “over-the-road” vehicle such as a truck used in transportation or may be any other type of machine that performs some type of operation associated with an industry such as mining, construction, farming, transportation, or any other industry known in the art. For example, the machine may be an off-highway truck; an earth-moving machine, such as a wheel loader, an excavator, a dump truck, a backhoe, a motor grader, or a material handler; a marine vehicle or machine; a locomotive; or any other machine known in the art. The term “machine” can also refer to stationary equipment, such as a generator that is driven by an internal combustion engine to generate electricity. The specific machine  100  illustrated in  FIG. 1  is a dump truck having a dump bed  118  actuated by a linear hydraulic cylinder  120 . 
       FIG. 2  shows a schematic view of a fuel supply system  106 , according to an aspect of the disclosure. The fuel supply system  106  includes a fluid conditioning module  200  having an inlet port  202  that is in fluid communication with a fuel reservoir  206  via a fuel suction conduit  208 . An outlet port  210  of the fluid conditioning module  200  may be in fluid communication with the IC engine  104  via a module outlet conduit  212 . The fluid conditioning module  200  may include pumps, valves, filters, sensors, heaters, coolers, controllers, combinations thereof, or any other structures known in the art to be beneficial to conditioning a fluid. 
     A power port  214  of the fluid conditioning module  200  is operatively coupled to a power source  216  via a power conduit  218 . The power source  216  may be an electrical power source, a hydraulic power source, a pneumatic power source, a shaft power source, combinations thereof, or any other power source known in the art. The power conduit  218  may include an electrical conductor, a fluid conduit, a shaft, or any other means for transmitting power known in the art. According to an aspect of the disclosure, the power source  216  is an electrical power source, and the power conduit  218  consists of one or more electrical conductors. 
     The fluid conditioning module  200  may be fluidly coupled to the fuel reservoir  206  via a low-pressure transfer pump  220 , which takes suction from the fuel reservoir  206  via the fuel suction conduit  208 . Alternatively, the fluid conditioning module  200  includes a pump, and the fuel reservoir  206  may provide sufficient net positive suction head to the fluid conditioning module  200  such that the low-pressure transfer pump  220  is not necessary, and is therefore not included in the fuel supply system  106 . 
     An inlet  222  of the low-pressure transfer pump  220  may be fluidly coupled to the fuel reservoir  206  via a filter or strainer  224 , a check valve  226 , or both. Alternatively or additionally, an outlet  228  of the low-pressure transfer pump  220  may be fluidly coupled to the inlet port  202  of the fluid conditioning module  200  via a filter or strainer  230 . Further, it will be appreciated that the inlet port  202  of the fluid conditioning module  200  may be fluidly coupled to the fuel reservoir  206  via the filter or strainer  224 , the check valve  226 , or both, independent of whether the fuel supply system  106  includes the low-pressure transfer pump  220 . The check valve  226  is configured to allow flow through the suction conduit  208  only in a direction from the fuel reservoir  206  toward the fluid conditioning module  200 . 
     According to the aspect illustrated in  FIG. 2 , the outlet port  210  of the fluid conditioning module  200  is fluidly coupled to the IC engine  104  via a high-pressure pump system  250 , which includes a high-pressure pump  252 . The high-pressure pump  252  may be a high-pressure unit pump that is coupled to a single fuel injector of the IC engine  104 , or a high-pressure common rail pump that is fluidly coupled to two or more fuel injectors  254  of the IC engine  104  via a common rail  256 . Therefore, according to an aspect of the disclosure, the fluid conditioning module  200  is in fluid communication with the IC engine  104  via at least one pump disposed downstream of the outlet port  210  of the fluid conditioning module  200  along a direction of fuel flow through the module outlet conduit  212 . 
     The fuel reservoir  206  may be in fluid communication with a pump drain conduit  260 , a fuel injector drain conduit  262 , or both, via a return conduit  264 . The return conduit  264  may optionally include a heat exchanger  266  that is configured to transfer heat away from a flow of fuel through the return conduit  264 . Further, the return conduit  264  may include an air bleed device  268  for separating gases from liquid fuel flowing through the return conduit  264  upstream of the fuel reservoir  206 . The fuel reservoir  206  may be a liquid fuel reservoir that supplies one or more liquid fuels to the IC engine  104 , such as, distillate diesel, biodiesel, dimethyl ether, seed oils, ethanol, methanol, combinations thereof, or any other combustible liquid known in the art. 
     Although the fluid conditioning module  200  is shown in the context of a fuel supply system  106  in  FIG. 2 , it will be appreciated that the fluid conditioning module  200  could be used to condition other fluids, such as, hydraulic fluid, coolant, water, lubricating oil, combinations thereof, or any other fluid known in the art. Unless specified otherwise, the term “fluid” is used herein to describe gases, liquids, slurries, combinations thereof, or other similar matter that tends to flow in response to applied sheer stress. 
       FIG. 3  shows a schematic view of a fluid conditioning module  200 , according to an aspect of the disclosure. The fluid conditioning module  200  includes a first pump  300 , a second pump  302 , a first filter  304 , a second filter  306 , a motor  308 , and a module controller  310 . 
     An inlet  312  to the first pump  300  is fluidly coupled to the inlet port  202  of the fluid conditioning module  200 , and therefore the fuel suction conduit  208 , via a first pump inlet conduit  314 . An outlet  316  from the first pump  300  is fluidly coupled to an inlet port  318  of the first filter  304  via a first filter inlet conduit  320 . An outlet port  322  of the first filter  304  is fluidly coupled to the first pump inlet conduit  314  at a node  324  via a first filter outlet conduit  326 . Accordingly, the first filter inlet conduit  320 , the first filter outlet conduit  326 , and the first pump inlet conduit  314  form a fluid recirculation loop  328  about the first pump  300 , which includes the first filter  304 . 
     An inlet  330  to the second pump  302  is fluidly coupled to the node  324  via a second pump inlet conduit  332 . In turn, the inlet  330  of the second pump  302  is fluidly coupled to the first filter outlet conduit  326  and the inlet port  202  of the fluid conditioning module  200  via the second pump inlet conduit  332 . According to an aspect of the disclosure, the first pump  300  may be a turbomachine, such as, for example, a centrifugal pump. According to another aspect of the disclosure, the second pump  302  may have a positive displacement design, such as, for example a gerotor or external gear pump construction. However, it will be appreciated that either the first pump  300  or the second pump  302  may be a turbomachine, a positive displacement pump, or any other pump known in the art, to satisfy the needs of a particular application. 
     An outlet  334  from the second pump  302  is fluidly coupled to an inlet port  336  of the second filter  306  via a second filter inlet conduit  338 . An outlet port  340  of the second filter  306  is fluidly coupled to the outlet port  210  of the fluid conditioning module  200  via a second filter outlet conduit  342 . The second filter outlet conduit  342  may include a check valve  344  that is configured to allow flow only in a direction from the second filter  306  toward the outlet port  210  of the fluid conditioning module  200 . 
     The fluid conditioning module  200  may include a pressure regulating valve  350  having an inlet  352  that is fluidly coupled to the second filter outlet conduit  342  at a node  354  via a regulating valve inlet conduit  356 . Although  FIG. 2  shows the node  354  located upstream of the check valve  344 , it will be appreciated that the node  354  could be located anywhere along the second filter inlet conduit  338  and the second filter outlet conduit  342 . 
     An outlet  358  of the pressure regulating valve  350  is fluidly coupled to the first filter inlet conduit  320  at a node  360  via a first drain conduit  362 . Accordingly, the outlet  358  of the pressure regulating valve  350  is fluidly coupled to the inlet port  318  of the first filter  304  via the first drain conduit  362 . Alternatively or additionally, the outlet  358  of the pressure regulating valve  350  may be fluidly coupled to the second pump inlet conduit  332  at a node  364  via a second drain conduit  366 . In turn, the outlet  358  of the pressure regulating valve  350  may be in fluid communication with the inlet  312  to the first pump  300  and the inlet to the second pump  302  via the second drain conduit  366 . 
     The pressure regulating valve  350  has a first configuration that blocks fluid communication between the inlet  352  and the outlet  358  of the pressure regulating valve  350 , and a second configuration that effects fluid communication between the inlet  352  and the outlet  358  of the pressure regulating valve  350 . Further, the pressure regulating valve  350  may actuate between its first configuration and its second configuration based on a difference between the pressure at the inlet  352  and a predetermined threshold value. According to an aspect of the disclosure, the pressure regulating valve  350  may toggle from its first configuration to its second configuration when the pressure at the inlet  352  exceeds a predetermined threshold value. According to another aspect of the disclosure, the pressure regulating valve  350  may operate proportionally between its first configuration and a wide open position based on a difference between the pressure at the inlet  352  and a predetermined threshold value. 
     The first pump  300  is operatively coupled to the motor  308  via a first shaft  370  for transmission of shaft power therebetween, and the second pump  302  is operatively coupled to the motor  308  via a second shaft  372  for transmission of shaft power therebetween. The motor  308  may be powered by electrical power, hydraulic power, pneumatic power, combinations thereof, or any other motor power source known in the art. 
     According to an aspect of the disclosure, the motor  308  is configured to drive the first shaft  370  at the same angular velocity as the second shaft  372 . According to another aspect of the disclosure, the motor  308  may include gearing  374  operatively coupled to the first shaft  370 , the second shaft  372 , or both, such that an angular velocity for the first shaft  370  is different from the angular velocity of the second shaft according to a prescribed relationship as a function of the angular velocity of the motor  308 . 
     The motor  308  is operatively coupled to the module controller  310  for control thereof, and the module controller  310  is operatively coupled to the power source  216  at the power port  214  via the power conduit  218 , as described previously. The fluid conditioning module  200  may include a pressure sensor  376  that is in fluid communication with the second filter outlet conduit  342 , and operatively coupled to the module controller  310  for transmission of data signals, power, or both, therebetween. Accordingly, the module controller  310  may exchange data signals, power transmission, or both, with the motor  308  or the pressure sensor  376 . 
     According to an aspect of the disclosure, the motor  308  is a variable speed motor and the module controller  310  is configured to vary a rotational speed of the motor  308 . Further, the module controller  310  may be configured to vary a speed of the motor  308  based on a comparison between a pressure signal from the pressure sensor  376  and a predetermined threshold value. According to another aspect of the disclosure, the motor  308  is a constant speed motor, and the module controller  310  is configured to actuate the motor  308  between a stopped condition and a fixed-speed condition. 
     The module controller  310  may be any purpose-built processor for effecting control of the fluid conditioning module  200 . It will be appreciated that the module controller  310  may be embodied in a single housing, or a plurality of housings distributed throughout the fluid conditioning module  200 . Further, the module controller  310  may include power electronics, preprogrammed logic circuits, data processing circuits, volatile memory, non-volatile memory, software, firmware, input/output processing circuits, combinations thereof, or any other controller structures known in the art. 
       FIG. 4  shows a schematic view of a fluid conditioning module  200 , according to an aspect of the disclosure. Similar to  FIG. 3 , the fluid conditioning module  200  in  FIG. 4  includes the first pump  300 , the second pump  302 , the first filter  304 , the second filter  306 , and the module controller  310 . However, the fluid conditioning module  200  in  FIG. 4  further includes a first motor  400  operatively coupled to the first pump  300  via the first shaft  370 , and a second motor  402  operatively coupled to the second pump  302  via the second shaft  372 . The first motor  400  and the second motor  402  may each be operatively coupled to the module controller  310  for control thereof. Either of the first motor  400  or the second motor  402  may be powered by electrical power, hydraulic power, pneumatic power, or any other motor power source known in the art. According to an aspect of the disclosure, the first shaft  370  is free from any mechanical coupling with the second shaft  372  that would prohibit rotation of the first shaft  370  independent of rotation with the second shaft  372 . 
     The first motor  400  and the second motor  402  may embody various combinations of fixed-speed and variable-speed characteristics as outlined below. According to an aspect of the disclosure, both the first motor  400  and the second motor  402  are variable speed motors, and the module controller  310  is configured to operate each of the first motor  400  and the second motor  402  at speeds independent of one another. According to another aspect of the disclosure, the first motor  400  is a variable speed motor and the second motor  402  is a fixed speed motor, and the module controller  310  is configured to operate the first motor  400  at a speed that is independent of a speed of the second motor  402 . According to another aspect of the disclosure, the first motor  400  is a fixed speed motor and the second motor  402  is a variable speed motor, and the module controller  310  is configured to operate the second motor  402  at a speed that is independent of a speed of the first motor  400 . 
     According to another aspect of the disclosure, both the first motor  400  and the second motor  402  are fixed speed motors, and the controller is configured to operate the first motor  400  and the second motor  402  independent of one another. It will be appreciated that the first motor  400  may have a fixed operating speed that is the same as or different from a fixed operating speed of the second motor  402 . 
       FIG. 5  shows a perspective view of a fluid conditioning module  200 , according to an aspect of the disclosure. The fluid conditioning module  200  may include a block  450  that functions to provide points of attachment for any of the components of the fluid conditioning module  200 , to define fluid passages to effect fluid communication between components of the fluid conditioning module  200 , or combinations thereof. It will be appreciated that the block  450  may be formed and consist of a single unitary part, or alternatively, the block  450  may include a plurality of parts fastened to one another by threaded fasteners, rivets, welding, brazing, interference fits, combinations thereof, or any other material fasteners or techniques known in the art. 
     In  FIG. 5 , a height or vertical direction  452  extends along the z-axis, a width direction  454  extends along the x-axis, and a depth direction  456  extends along the y-direction, where the x-axis, the y-axis, and the z-axis may all be mutually normal or perpendicular to one another. 
     The first filter  304  and the second filter  306  are each mounted to a lower surface  460  of the block  450 . A longitudinal axis  462  of the first filter  304  and a longitudinal axis  464  of the second filter  306  may each extend away from the lower surface  460  of the block along the height direction  452 . The longitudinal axis  462  of the first filter  304  may be substantially parallel to the longitudinal axis  464  of the second filter  306 . Further, the longitudinal axis  462  of the first filter  304  and the longitudinal axis  464  of the second filter  306  may each lie in a plane defined by the width direction  454  and the height direction  452 . 
     The block  450  may define the inlet port  202 , the outlet port  210 , or both, of the fluid conditioning module  200 . It will be appreciated that the block  450  may include fluid fittings coupled thereto, and that such fluid fittings may be said to part of the block  450  and define the inlet port  202 , the outlet port  210 , or both. 
     As shown in  FIG. 5 , the block  450  includes a first block portion  470 , a second block portion  472  fastened to the upper surface  466  of the first block portion  470 , and a third block portion  474  fastened to the upper surface  466  the first block portion  470 . The second block portion  472  and the third block portion  474  each extend away from the upper surface  466  of the first block portion  470  along the height direction  452 . Alternatively, it will be appreciated that combinations of the first block portion  470 , the second block portion  472 , and third block portion  474  may be machined, cast, or otherwise formed as a single unitary piece. 
     The second pump  302  may be disposed at least partly within the third block portion  474 . According to an aspect of the disclosure, the second pump  302  is disposed completely within the third block portion  474 , except for the second shaft  372 , which may extend outside the third block portion  474  to the motor  308 . As discussed below, each of the first block portion  470 , the second block portion  472 , and the third block portion  474  may define fluid passages therein, thereby effecting fluid communication between the various components of the fluid conditioning module  200 . 
     The first pump  300 , the second pump  302 , and the motor  308  are shown fastened to an upper surface  466  of the first block portion  470 , where the upper surface  466  of the block  450  is opposite the lower surface  460  of the block along the height direction  452 . The first pump  300 , the second pump  302 , and the motor  308  may be fastened to the block  450  by threaded fasteners, or any other fasteners known in the art. Although only one motor  308  is shown in  FIG. 5 , it will be appreciated that the motor  308  could be replaced by the first motor  400  and the second motor  402  shown schematically in  FIG. 4 , without changing the arrangement of the first pump  300 , the first shaft  370 , the second pump  302 , and the second shaft  372  along the width direction  454 . 
     The second block portion  472  and the third block portion  474  each extend away from the upper surface  466  of the first block portion  470  along the height direction  452 . The second pump  302  may be disposed at least partly within the third block portion  474 . According to an aspect of the disclosure, the second pump  302  is disposed completely within the third block portion  474 , except for the second shaft  372 , which extends outside the third block portion  474  to the motor  308 . 
     The module controller  310  may be fastened to the motor  308 , or otherwise fastened to the block  450 , either directly or indirectly through another component. As discussed previously, the module controller  310  receives power from a power source  216  via a power conduit  218  coupled to the power port  214  of the fluid conditioning module  200 . 
     Referring now to  FIGS. 6-8 ,  FIG. 6  shows a partial cross sectional view of the fluid conditioning module  200  illustrated in  FIG. 5 , according to an aspect of the disclosure;  FIG. 7  shows a partial cross sectional view of the fluid conditioning module  200  illustrated in  FIG. 5 , according to an aspect of the disclosure; and  FIG. 8  shows a partial cross sectional view of the fluid conditioning module  200  shown in  FIG. 5 , according to an aspect of the disclosure. 
     In  FIG. 6 , the fluid conditioning module  200  is shown without the first filter  304  and the second filter  306 , to illustrate the a first filter mount  500  and a second filter mount  502 , defined by the lower surface  460  of the block  450 . The first filter mount  500  may define a first filter inlet aperture or port  504 , which may effectively define a downstream terminal end of the first filter inlet conduit  320  (see  FIG. 8 ), and may define a first filter outlet aperture or port  506 , which may effectively define an upstream terminal end of the first filter outlet conduit  326 . The second filter mount  502  may define a second filter inlet aperture or port  508 , which may effectively define a downstream terminal end of the second filter inlet conduit  338  (see  FIG. 3 ), and may define a second filter outlet aperture or port  510 , which may effectively define an upstream terminal end of the second filter outlet conduit  342 . The first filter mount  500  and the second filter mount  502  may also include filter fastening features, such as, for example, internal threads, external threads, clamps, or other filter fastening structures known in the art. 
     Each of the first block portion  470 , the second block portion  472 , and the third block portion  474  may define fluid passages therein, thereby effecting fluid communication between the various components of the fluid conditioning module  200 . For example, as shown in  FIGS. 6 and 7 , the second block portion  472  may define the fluid node  324  therein, such that the second block portion  472  effects fluid communication between the first filter outlet conduit  326 , the first pump inlet conduit  314 , the second pump inlet conduit  332  (see  FIG. 7 ), and a module inlet conduit  512 . Further as shown in  FIG. 8 , the first block portion  470  may define the fluid node  354  therein, such that the first block portion  470  effects fluid communication between the second filter outlet conduit  342  and the first drain conduit  362  via the pressure regulating valve  350 . 
     Referring to  FIG. 6 , a longitudinal axis  520  of the first shaft  370  may be substantially parallel with a longitudinal axis  522  of the second shaft  372 . According to another aspect of the disclosure, the longitudinal axis  520  of the first shaft  370  may be substantially collinear with the longitudinal axis  522  of the second shaft  372 . Further, each of the longitudinal axis  520  of the first shaft  370  and the longitudinal axis  522  of the second shaft  372  may be substantially aligned with the width direction  454 . 
       FIG. 9  shows a schematic view of a fluid conditioning module  600 , according to an aspect of the disclosure. The fluid conditioning module  600  is similar to the fluid conditioning module  200  shown in  FIG. 3 ; however, the fluid conditioning module  600  includes a recirculation pump unit  602  in place of the first pump  300 , a delivery pump unit  604  in place of the second pump  302 , and a motor unit  606  in place of the motor  308 . The recirculation pump unit  602  may include one or more pumps, and the delivery pump unit  604  may include one or more pumps. The motor unit  606  is operatively coupled to the module controller  310  and may include one or more motors. The recirculation pump unit  602  and the delivery pump unit  604  may share common features or attributes with the first pump  300  and the second pump  302 , respectively. Further, it will be appreciated that the fluid conditioning module  600  may otherwise have any of the features, fluid connections, applications, or attributes of the fluid conditioning module  200  illustrated in  FIGS. 2-8 , for example. 
     An outlet  608  of the recirculation pump unit  602  is fluidly coupled to the inlet port  318  of the first filter  304  via the first filter inlet conduit  320 , and an inlet  610  of the recirculation pump unit  602  is fluidly coupled to the fluid node  324 . The recirculation pump unit  602  is operatively coupled to the motor unit  606  via the first shaft  370 . Accordingly, the recirculation pump unit  602  is configured to receive shaft power from the motor unit  606  and recirculate a flow of fluid through the fluid recirculation loop  328 . 
     According to an aspect of the disclosure, the recirculation pump unit  602  includes a centrifugal pump. According to another aspect of the disclosure, the centrifugal pump includes a housing  530  (see  FIG. 6 ) configured to receive an impeller  532  (see  FIG. 6 ) from a plurality of impellers, where each impeller  532  of the plurality of impellers effects a unique flow-versus-pressure rise characteristic when operating within the housing  530 . 
     An outlet  612  of the delivery pump unit  604  is fluidly coupled to the inlet port  336  of the second filter  306  via the second filter inlet conduit  338 , and an inlet  614  of the delivery pump unit  604  is fluidly coupled to the fluid node  364 . The delivery pump unit  604  is operatively coupled to the motor unit  606  via the second shaft  372 . Accordingly, the delivery pump unit  604  is configured to receive shaft power from the motor unit  606  and deliver a flow of fluid through the second filter  306 . 
       FIG. 10  shows a schematic view of a delivery pump unit  604 , according to an aspect of the disclosure. In  FIG. 10 , the delivery pump unit  604  includes a first delivery pump  620  and a second delivery pump  622 . The first delivery pump  620  is operatively coupled to the motor unit  606  via the shaft  372 , and operatively coupled to the second delivery pump  622  via a shaft  624 . It will be appreciated that the shaft  372  and the shaft  624  may be integrated into one unitary shaft, or comprise a plurality of shafts fastened together for transmitting torque therebetween. 
     The first delivery pump  620  and the second delivery pump  622  are plumbed in parallel, such that an inlet  626  of the first delivery pump  620  and an inlet  628  of the second delivery pump  622  are fluidly coupled to the inlet  614  of the delivery pump unit  604  via an inlet manifold  630 , and an outlet  632  of the first delivery pump  620  and an outlet  634  of the second delivery pump  622  are fluidly coupled to the outlet  612  of the delivery pump unit  604  via an outlet manifold  636 . Accordingly, both the first delivery pump  620  and the second delivery pump  622  receive fluid from node  364  via the inlet manifold  630 , and deliver fluid to the inlet port  336  of the second filter  306  via the outlet manifold  636 . 
       FIG. 11  shows a schematic view of a delivery pump unit  604 , according to an aspect of the disclosure. Similar to  FIG. 10 , the delivery pump unit  604  illustrated in  FIG. 11  includes a first delivery pump  620  and a second delivery pump  622 , but further includes a third delivery pump  640 . The third delivery pump  640  is operatively coupled to the second delivery pump  622  via a shaft  642 . It will be appreciated that the shaft  372 , the shaft  624 , and the shaft  642  may be integrated into one unitary shaft, or comprise a plurality of shafts fastened together for transmitting torque therebetween. 
     The third delivery pump  640  is plumbed in parallel with both the first delivery pump  620  and the second delivery pump  622 , such an inlet  644  of the third delivery pump  640  is in fluid communication with the inlet  614  of the delivery pump unit  604  via the inlet manifold  630 , and an outlet  646  of the third delivery pump is in fluid communication with the outlet  612  of the delivery pump unit  604  via the outlet manifold  636 . It will be appreciated that the delivery pump unit  604  may include any number of delivery pumps greater than or equal to two, which are plumbed in parallel with one another to suit a particular application. 
     According to an aspect of the disclosure, the first delivery pump  620 , the second delivery pump  622 , the third delivery pump  640 , or combinations thereof, are positive displacement pumps. According to another aspect of the disclosure, the first delivery pump  620 , the second delivery pump  622 , the third delivery pump  640 , or combinations thereof are gerotor positive displacement pumps. 
       FIG. 12  shows a schematic view of a motor unit  606 , according to an aspect of the disclosure. The motor unit  606  illustrated in  FIG. 12  includes a first motor  650  and a second motor  652 . The first motor is operatively coupled to the recirculation pump unit  602  via the shaft  370 , and operatively coupled to the second motor  652  via a shaft  654 . The second motor  652  is also operatively coupled to the delivery pump unit  604  via the shaft  372 . The first motor  650  and the second motor  652  are each operatively coupled to the module controller  310  for control thereof. 
     It will be appreciated that the shaft  370 , the shaft  654 , and the shaft  372  may be integrated into one unitary shaft, or comprise a plurality of shafts fastened together for transmitting torque therebetween. According to an aspect of the disclosure, each of the shaft  370 , the shaft  654 , and the shaft  372  rotates at the same rotational speed. 
       FIG. 13  shows a schematic view of a motor unit  606 , according to an aspect of the disclosure. Similar to  FIG. 12 , the motor unit  606  illustrated in  FIG. 13  includes a first motor  650  and a second motor  652 , but the motor unit  606  illustrated in  FIG. 13  further includes a third motor  656 . The third motor  656  is operatively coupled to the second motor  652  via a shaft  658 , and operatively coupled to the delivery pump unit  604  via the shaft  372 . The third motor  656  is also operatively coupled to the module controller  310  for control thereof. 
     It will be appreciated that the shaft  370 , the shaft  654 , the shaft  658 , and the shaft  372  may be integrated into one unitary shaft, or comprise a plurality of shafts fastened together for transmitting torque therebetween. According to an aspect of the disclosure, each of the shaft  370 , the shaft  654 , the shaft  658 , and the shaft  372  rotates at the same rotational speed. According to another aspect of the disclosure, the first motor  650 , the second motor  652 , the third motor  656 , or combinations thereof, are brushless DC electric motors. 
       FIG. 14  shows a schematic side view of a fluid conditioning module  600 , according to an aspect of the disclosure. The fluid conditioning module  600  of  FIG. 14  includes a recirculation pump unit  602 , a motor unit  606 , and a delivery pump unit  604 , all fastened to a block  450  via threaded fasteners, rivets, welding, brazing, clamps, or any other fastening structures known in the art. Similar to  FIGS. 10 and 12 , the motor unit  606  includes a first motor  650  and a second motor  652 , and the delivery pump unit  604  includes a first delivery pump  620  and a second delivery pump  622 . According to an aspect of the disclosure, the recirculation pump unit  602 , the motor unit  606 , the delivery pump unit  604 , or combinations thereof, are fastened to the upper surface  466  of the block  450 , opposite the first filter mount  500  and the second filter mount  502  disposed on the lower surface  460  of the block  450 . 
     Similar to  FIGS. 6-8 , the block  450  in  FIG. 14  may define various internal flow passages or flow conduits. For example, the block  450  may define fluid conduits to effect fluid communication between the inlet  610  to the recirculation pump unit  602  and the module inlet port  202 , and between the outlet  608  of the recirculation pump unit  602  and the inlet port  504  of the first filter mount  500 . The block  450  may further define fluid conduits to effect fluid communication between the outlet port  506  of the first filter mount  500  and the inlet  626  of the first delivery pump  620  and the inlet  628  of the second delivery pump  622 , and effect fluid communication between the outlet  632  of the first delivery pump  620  and the outlet  634  of the second delivery pump  622  and the inlet port  508  of the second filter mount  502 . The block  450  may further define fluid conduits to effect fluid communication between the outlet port  510  of the second filter mount  502  and the module outlet port  210 . Thus, the block  450  may define the inlet manifold  630 , the outlet manifold  636 , or both, illustrated in  FIG. 10 . However, it will be appreciated that any of the above-described fluid conduits could be defined, either entirely or in part, by structures such as tubes or pipes distinct from the block  450 . 
     As shown in  FIG. 14 , the first motor  650  may be operatively coupled to the second motor  652  by the shaft  654 , such that the first motor  650  and the second motor  652  are disposed adjacent to one another. Further, the first delivery pump  620  may be operatively coupled to the second delivery pump  622  by the shaft  624 , such that the first delivery pump  620  is disposed adjacent to the second delivery pump  622 . 
     A bearing  660  may be fastened to the block  450 , and disposed on the shaft  370  between the recirculation pump unit  602  and the first motor  650 , for rotational support of the shaft  370 . A bearing  662  may be fastened to the block  450 , and disposed on the shaft  372  between the second motor  652  and the first delivery pump  620 , for rotational support of the shaft  372 . A bearing  664  may be fastened to the block  450 , and disposed on the shaft  624  on an outboard side  666  of the second delivery pump  622 , for rotational support of the shaft  624 . Alternatively or additionally, the bearing  660 , the bearing  662 , the bearing  664 , or combinations thereof, may be incorporated into one or more of the recirculation pump unit  602 , the motor unit  606 , and the delivery pump unit  604 . 
     According to an aspect of the disclosure, longitudinal axes for each of the shaft  370 , the shaft  654 , the shaft  372 , and the shaft  624  are all parallel to one another. According to another aspect of the disclosure, longitudinal axes for each of the shaft  370 , the shaft  654 , the shaft  372 , and the shaft  624  are all coincident with one another along a common shaft longitudinal axis  668 . However, it will be appreciated that other arrangements of the shaft longitudinal axes are contemplated to be within the scope of the disclosure. 
       FIG. 15  shows a schematic side view of a fluid conditioning module  600 , according to an aspect of the disclosure. The fluid conditioning module  600  of  FIG. 15  includes a recirculation pump unit  602 , a motor unit  606 , and a delivery pump unit  604 , all fastened to a block  450  via threaded fasteners, rivets, welding, brazing, clamps, or any other fastening structures known in the art. Similar to  FIG. 14 , the motor unit  606  includes a first motor  650  and a second motor  652 , and the delivery pump unit  604  includes a first delivery pump  620  and a second delivery pump  622 ; however, the motor unit  606  of  FIG. 15  further includes a third motor  656 , and the delivery pump unit  604  further includes a third delivery pump  640 . 
     Similar to  FIG. 14 , the block  450  in  FIG. 15  may define various internal flow passages or flow conduits. For example, in addition to the fluid conduits defined by the block  450  in and discussed with respect to  FIGS. 6-8 and 14 , the block  450  may further define fluid conduits to effect fluid communication between the outlet port  506  of the first filter mount  500  and the inlet  644  to the third delivery pump  640 , and between the outlet  646  of the third delivery pump  640  and the inlet port  508  of the second filter mount  502 . Thus, the block  450  may define the inlet manifold  630 , the outlet manifold  636 , or both, illustrated in  FIG. 11 . However, it will be appreciated that any of the above-described fluid conduits could be defined, either entirely or in part, by structures such as tubes or pipes distinct from the block  450 . 
     As shown in  FIG. 15 , the third motor  656  may be operatively coupled to the second motor  652  by the shaft  658 , such that the third motor  656  and the second motor  652  are disposed adjacent to one another. Further, the third delivery pump  640  may be operatively coupled to the second delivery pump  622  by the shaft  642 , such that the third delivery pump  640  is disposed adjacent to the second delivery pump  622 . 
     A bearing  662  may be fastened to the block  450 , and disposed on the shaft  372  between the third motor  656  and the first delivery pump  620 , for rotational support of the shaft  372 . A bearing  664  may be fastened to the block  450 , and disposed on the shaft  642  on an outboard side  670  of the third delivery pump  640 , for rotational support of the shaft  642 . Alternatively or additionally, the bearing  660 , the bearing  662 , the bearing  664 , or combinations thereof, may be incorporated into one or more of the recirculation pump unit  602 , the motor unit  606 , and the delivery pump unit  604 . 
     According to an aspect of the disclosure, longitudinal axes for each of the shaft  370 , the shaft  654 , the shaft  658 , the shaft  372 , the shaft  624 , and the shaft  642  are all parallel to one another. According to another aspect of the disclosure, longitudinal axes for each of the shaft  370 , the shaft  654 , the shaft  658 , the shaft  372 , the shaft  624 , and the shaft  642  are all coincident with one another along a common shaft longitudinal axis  668 . However, it will be appreciated that other arrangements of the shaft longitudinal axes are contemplated to be within the scope of the disclosure. 
       FIG. 16  shows a schematic side view of a fluid conditioning module  600 , according to an aspect of the disclosure. The fluid conditioning module  600  of  FIG. 16  includes a recirculation pump unit  602 , a motor unit  606 , and a delivery pump unit  604 , all fastened to a block  450  via threaded fasteners, rivets, welding, brazing, clamps, or any other fastening structures known in the art. Similar to  FIG. 14 , the motor unit  606  includes a first motor  650  and a second motor  652 , the delivery pump unit  604  includes a first delivery pump  620  and a second delivery pump  622 , and the block  450  in  FIG. 16  may define any of the various internal flow passages or flow conduits defined in or discussed with respect to  FIGS. 6-8 and 14 . 
     However, in  FIG. 16  the elements of the motor unit  606  and the delivery pump unit  604  are interspersed with one another along the block  450 . The first delivery pump  620  is operatively coupled to the first motor  650  by the shaft  372 , and operatively coupled to the second motor  652  by the shaft  670 . Further, the second motor  652  is operatively coupled to the second delivery pump  622  by the shaft  672 . Thus, the first motor  650  may be disposed adjacent to the first delivery pump  620 , and the second motor  652  may be disposed adjacent to the second delivery pump  622 . 
     A bearing  662  may be fastened to the block  450 , and disposed on the shaft  670  between the second motor  652  and the first delivery pump  620 , for rotational support of the shaft  670 . A bearing  664  may be fastened to the block  450 , and disposed on the shaft  672  on an outboard side  666  of the second delivery pump  622 , for rotational support of the shaft  672 . Alternatively or additionally, the bearing  660 , the bearing  662 , the bearing  664 , or combinations thereof, may be incorporated into one or more of the recirculation pump unit  602 , the motor unit  606 , and the delivery pump unit  604 . 
     According to an aspect of the disclosure, longitudinal axes for each of the shaft  370 , the shaft  372 , the shaft  670 , and the shaft  672  are all parallel to one another. According to another aspect of the disclosure, longitudinal axes for each of shaft  370 , the shaft  372 , the shaft  670 , and the shaft  672  are all coincident with one another along a common shaft longitudinal axis  668 . However, it will be appreciated that other arrangements of the shaft longitudinal axes are contemplated to be within the scope of the disclosure. 
     INDUSTRIAL APPLICABILITY 
     The present disclosure is applicable to fluid conditioning systems and, more particularly, to fuel conditioning modules for combustion engines. 
     Fuel injection pressures for direct injection compression ignition engines have increased over time at least partly in response to more stringent emissions regulations and incentives to improve fuel economy. And in response to this trend, Applicants have discovered that fuel injection system designs for higher injection pressures may exhibit higher sensitivity to fuel cleanliness, especially with respect to fuel-borne particulates. Further, the increased particulate sensitivity extends not only to the total volume fraction of particulates in the fuel, but also the maximum tolerable particle size. In turn, improved fuel filtration and conditioning systems can improve component service life through mitigation of surface wear and scuffing, heat-induced wear, or combinations thereof. 
     While conventional methods exist for improving filtration of fuel in a machine  100 , Applicants recognized that the conventional methods tend to be bulky and expensive. As a result, Applicants have developed improvements to the conventional filtering methods within current design constraints for product packaging, cost, and maintainability, as described herein. 
     Referring to  FIGS. 3 and 4 , aspects of the disclosure provide a fluid conditioning module  200  including a first pump  300  operating in a fluid recirculation loop  328  with a first filter  304 , in addition to a second pump  302  for delivering fuel from the fluid recirculation loop  328  to an engine  104  via a second filter  306 . Applicants discovered that improved fuel filtering could be achieved within the aforementioned packaging, cost, and maintainability constraints by operating the first pump  300  a flow rate that is at least twice as high as the flow rate through the second pump  302 . According to an aspect of the disclosure, the flow rate through the first pump  300  is greater than or equal to five times greater than the flow rate through the second pump  302 . 
     As a result, a parcel of fuel entering the fluid conditioning module  200  from the fuel reservoir  206  will likely flow through the first filter  304  multiple times before advancing to the engine  104  via the second pump  302  and the second filter  306 , thereby improving fuel quality with each successive pass through the first filter  304 . While some conventional systems may effect so-called “kidney loop” operation with a separate system that recirculates fuel back to a fuel reservoir, Applicants discovered packaging and cost advantages by incorporating the fluid recirculation loop  328  into the fluid conditioning module  200  without recirculation to the fuel reservoir  206 . Instead, the second pump  302  takes suction from the fluid node  324 , which is in fluid communication with the outlet port  322  of the first filter  304 . In turn, Applicants have identified improvements in fuel system component service life, especially for components operating downstream of a high-pressure common rail pump  252  (e.g., high-pressure common rail fuel injectors  254 ) within established limits for fuel system packaging size and cost. 
     Accordingly, during operation of the fluid conditioning module, a first flow of fuel enters the inlet  312  of the first pump  300 . The first flow of fuel may have originated from the inlet port  202  to the fluid conditioning module  200 , the fluid recirculation loop  328 , the pressure regulating valve  350 , or combinations thereof. The first pump  300  drives the first flow of fuel through the first filter  304  and back to the fluid node  324 . 
     At node  324 , the first flow of fuel may be split into a second flow of fuel that proceeds back to the inlet  312  of the first pump  300 , and a third flow of fuel that proceeds to the inlet  330  of the second pump  302 . According to an aspect of the disclosure, the second flow of fuel constitutes about 50-75% of the first flow of fuel, with the balance proceeding to the inlet  330  of the second pump  302 . 
     Improvements to filtration performance are further realized by pressurization of the fuel entering the first filter  304  by the first pump  300 , which enables the use of finer filtration media in the first filter  304 , the second filter  306 , or both. For example, while some conventional approaches may only accommodate 10 μm filtration media within prescribed design constraints, aspects of the present disclosure enable use of finer 4 μm filtration media within the same design constraints; thereby further improving filtration performance and fuel quality. According to an aspect of the disclosure, the first filter  304  includes a single stage of 4 μm filtration media. According to another aspect of the disclosure, the first filter  304  includes a single stage of 4 μm filtration media, and the second filter  306  includes two stages of 4 μm filtration media arranged in series. According to another aspect of the disclosure, the two stages of 4 μm filtration media in the second filter  306  are arranged coaxially in series with one another. However, persons having skill in the art will appreciate that either the first filter  304  or the second filter  306  may include multiple filter elements in a single filter housing, multiple filter housings, or combinations thereof. 
     According to an aspect of the disclosure, the module controller  310  is configured to operate the first pump  300  with a discharge pressure at the outlet  316  up to about 18 psi (125 kPa). According to another aspect of the disclosure, the module controller  310  is configured to operate the second pump  302  with a discharge pressure at the outlet  334  of about 87 psi (600 kPa). Thus, it will be appreciated that the fluid conditioning module  200  does not include a high-pressure common rail pump capable of increasing fuel pressure to the final injection pressure. Instead, according to some aspects of the disclosure, the fluid conditioning module  200  performs a low-pressure transfer function to supply high-quality fuel to a high-pressure common rail pump  252 . 
     The module controller  310  is configured to operate the first pump  300  at a flow rate that is higher than a flow rate of the second pump  302 , and the module controller  310  may achieve this result in a number of ways depending upon the application. 
     Referring to  FIG. 3 , where both the first pump  300  and the second pump  302  are driven by a single motor  308 , the first pump  300  may be selected to have a pumping characteristic such that, at the target pressure rise across the first pump, the flow rate through the first pump  300  is greater than the flow rate through the second pump  302 , when the second pump  302  is also operated at its target pressure rise and the second pump  302  is operated at the same speed as the first pump  300 . Accordingly, for the aforementioned pumping characteristics and same-speed operation of the first pump  300  and the second pump  302 , the module controller  310  is configured to operate the first pump  300  at a higher flow rate than that of the second pump  302  by operating both the first pump  300  and the second pump  302  at the same speed. 
     Alternatively, as discussed above, the motor  308  may include gearing  374 , such that the first pump  300  operates at a higher speed than the second pump  302  for any given operating speed of the motor  308 . Accordingly, for the configuration where the first pump  300  and the second pump  302  have substantially the same pumping characteristic, operating the first pump  300  at a higher speed than the second pump  302 , as a result of the gearing  374 , the controller may be configured to operate the first pump  300  at a higher flow rate than that of the second pump  302  by operating the motor  308  at a given speed or range of speeds. Further, it will be appreciated that the gearing  374  may be combined with different pumping characteristics for the first pump  300  and the second pump  302  to achieve the desired relative flow rates between the first pump  300  and the second pump  302 . 
     Referring now to  FIG. 4 , where the first pump  300  and the second pump  302  are operated independently by separate motors  400  and  402 , respectively, it will be appreciated that the module controller  310  may be configured to tailor the flow rate of the first pump  300  relative to the flow rate of the second pump  302  by operating the first motor  400  and the second motor  402  at different speeds. As discussed previously, the first motor  400  and the second motor  402  may be variable speed motors, for example, and the module controller  310  may tailor the speeds of the first motor  400  and the second motor  402  to achieve the desired relative flow rates from the first pump  300  and the second pump  302 . 
     Alternatively, if one of the first motor  400  and the second motor  402  were a variable speed motor and the other were a fixed speed motor, the module controller  310  could tailor the relative flow rates between the first pump  300  and the second pump  302  by varying the speed of the motor having variable speed capability. Further still, if the first motor  400  and the second motor  402  were each fixed speed motors, then the fixed speeds of the two motors could be selected in combination with the pumping characteristics of the first pump  300  and the second pump  302  to effect the desired relative flow rates between the first pump  300  and the second pump  302 . Accordingly, the module controller  310  would be configured to operate the first pump  300  at a higher flow rate than the second pump  302  by operating the two fixed-speed motors  400 ,  402  at different respective fixed speeds. 
     Similar to operation of the first pump  300  and the second pump  302 , the module controller  310  may be configured to operate the recirculation pump unit  602  and the delivery pump unit  604  such that a flow rate through the recirculation pump unit  602  is greater than a flow rate through the delivery pump unit  604 . Further, it will be appreciated that any of the aforementioned operating methods or procedures applicable to the first pump  300  and the second pump  302  may be effected for the recirculation pump unit  602  and the delivery pump unit  604 , respectively, by action of the module controller  310 . 
     The module controller  310  may be configured to monitor the operating speed of the motor  308 , the first motor  400 , the second motor  402 , or combinations thereof, for purposes of identifying a filter loading level of the first filter  304 , the second filter  306 , or both. Further, the module controller  310  may be configured to monitor a signal from the pressure sensor  376  and compare the pressure signal to a prescribed threshold value. The signal from the pressure sensor  376  dropping below the prescribed threshold value may be indicative a high loading state of the first filter  304 , the second filter  306 , or both. In response to identifying a high loading state of filters within the fluid conditioning module  200 , the module controller  310  may be configured to transmit a signal to the machine controller  130  or a display in the machine cab  122  informing an operator of the high filter loading condition within the fluid conditioning module  200 . 
     Electrically driven pumps  300 ,  302  within the fluid conditioning module  200  may advantageously facilitate priming after filter service, as the engine need not be running to drive either the first pump  300 , the second pump  302 , or both, but instead use electrical energy stored in a battery to operate the fluid conditioning module  200 . Similarly, electrically driven pumps  300 ,  302  may provide advantages with respect to starting the IC engine  104 , because the electrically driven pumps  300 ,  302  do not require shaft power from the engine to pressurize the high-pressure pump system  250  prior to starting the IC engine  104 . 
     It will be appreciated that standardized, modular, and compact nature of the fluid conditioning module  200  facilitates application and installation engineering, particularly in light of only three connections between the machine  100  and the fluid conditioning module  200 , namely: the inlet port  202 , the outlet port  210 , and the power port  214 . Further, the compact and modular design of the fluid conditioning module  200  advantageously lends itself for mounting on a fuel tank or the chassis  114  of a machine  100 , thereby avoiding the higher vibration environment of the IC engine  104 . Applicants have discovered that vibration may diminish filtration performance through disruption of filter cake captured on filter media of the first filter  304  or the second filter  306 . 
     Moreover, referring to  FIGS. 9-16 , aspects of the disclosure provide a fluid conditioning system having a fluid capacity that is scalable using modular components. For example, the fluid capacity of the delivery pump unit  604  may be tailored to a particular application by choosing an appropriate number of modular delivery pumps greater than or equal to one. For example,  FIGS. 10, 14, and 16  illustrate non-limiting configurations for the fluid conditioning module  600  including a first delivery pump  620  and a second delivery pump  622 ; and  FIGS. 11 and 15  illustrate non-limiting configurations for the fluid conditioning module  600  including a first delivery pump  620 , a second delivery pump  622 , and a third delivery pump  640 . 
     Further, the shaft power capacity of the motor unit  606  may be tailored to a particular application by choosing an appropriate number of modular motors greater than or equal to one. For example,  FIGS. 12, 14, and 16  illustrate non-limiting configurations for the fluid conditioning module  600  including a first motor  650  and a second motor  652 ; and  FIGS. 13 and 15  illustrate non-limiting configurations for the fluid conditioning module  600  including a first motor  650 , a second motor  652 , and a third motor  656 . 
     According to an aspect of the disclosure, each delivery pump of the delivery pump unit  604  has a common operating characteristic, such as a common characteristic relationship between flow rate, pressure rise, and speed, for example. According to another aspect of the disclosure, each motor in the motor unit  606  has a common operating characteristic, such as a common characteristic relationship between shaft torque, shaft speed, electric current, and electric voltage, for example. Therefore, a manufacturer or operator of the fluid conditioning module  600  need only stock a single model of delivery pump, motor, or both, to accommodate an array of fluid capacities for the delivery pump unit  604 . 
     Moreover, when the recirculation pump unit  602  unit includes a centrifugal pump, a common centrifugal pump housing  530  (see  FIG. 6 ) may be used across a range of fluid capacities for the fluid conditioning module  600  by selecting one of a plurality of distinct centrifugal impellers  532  (see  FIG. 6 ) for use in the common centrifugal housing  530 . Therefore, a manufacturer or operator of the fluid conditioning module  600  need only stock a single common centrifugal pump housing  530  for the recirculation pump unit  602  to accommodate an array of fluid capacities for the recirculation pump unit  602 . 
     Aspects of the disclosure that use one or more identical electric motors for the motor unit  606  enable reduced cost through simplified design of the module controller  310 . Indeed, a common motor controller architecture may be advantageously replicated in the module controller  310  to accommodate any number of modular electric motors in the motor unit  606 , compared to manufacturing or purchasing a plurality of different controller architectures. 
     In addition to economies related to reduced inventory part numbers, modular components having common operating characteristics for the fluid conditioning module  600  may also provide cost savings to manufacturers and operators of the fluid conditioning module  600  by increasing the volumes of modular components manufactured or purchased, instead of purchasing lower quantities across a plurality of components having different operating characteristics. Accordingly, aspects of the disclosure enable reduced manufacturing and operating costs of a family of fluid conditioning modules  600  spanning a wide range of fluid capacities. 
     Any of the methods or functions described herein may be performed by or controlled by the module controller  310 . Further any of the methods or functions described herein may be embodied in a machine-readable non-transitory medium for causing the module controller  310  to perform the methods or functions described herein. Such machine-readable non-transitory media may include magnetic disks, optical discs, solid state disk drives, combinations thereof, or any other machine-readable non-transitory medium known in the art. Moreover, it will be appreciated that the methods and functions described herein may be incorporated into larger control schemes for the engine  104 , the machine  100 , or combinations thereof, including other methods and functions not described herein. Accordingly, the module controller  310  may be operatively coupled to the machine controller  130  for communication therewith, or at least partly embodied within the machine controller  130 . 
     It will be appreciated that the foregoing description provides examples of the disclosed system and technique. However, it is contemplated that other implementations of the disclosure may differ in detail from the foregoing examples. All references to the disclosure or examples thereof are intended to reference the particular example being discussed at that point and are not intended to imply any limitation as to the scope of the disclosure more generally. All language of distinction and disparagement with respect to certain features is intended to indicate a lack of preference for those features, but not to exclude such from the scope of the disclosure entirely unless otherwise indicated. 
     Unless specified otherwise, use of the word “substantially” herein means “considerable in . . . extent,” or “largely but not necessarily wholly that which is specified.” 
     Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context.