Vehicle electrical distribution system and method of use therefor

[0001] This invention relates to electrical distribution systems for vehicle chassis having systems controllable by nonmechanical control signals.

[0002] Vehicle chassis typically include a multitude of electrical devices that must be in electrical communication with one another in order to properly function. Prior art vehicle chassis typically use complex bundles of wires, or wiring harnesses, to operatively interconnect chassis electrical devices. Wiring harnesses are labor intensive to produce and to route through the chassis between electrical devices. Wiring harnesses are typically of considerable length and have a multitude of branches, and can therefore be cumbersome to handle. The particularly large number of electrical devices in fuel cells and by-wire control systems exacerbates the problems inherent in wiring harnesses.

[0003] Furthermore, vehicle models having different quantities or types of electrical devices typically employ differently-configured wiring harnesses, resulting in increased wiring harness inventory requirements at assembly plants and reduced flexibility in vehicle assembly.

[0004] A vehicle chassis includes a steering system, a braking system, an energy conversion system, and an energy storage system operatively connected to the energy conversion system. The steering system, the braking system and the energy conversion system are operatively connected to at least one wheel, and at least two of the steering system, braking system, and energy conversion system are responsive to nonmechanical control signals. A plurality of electrical devices at least partially forms at least one of the steering system, the braking system, the energy conversion system and the energy storage system.

[0005] The vehicle chassis also includes an electrical distribution system that has at least one junction box. The at least one junction box includes at least one exposed electrical connector. Each of the plurality of electrical devices is operatively connected to the at least one junction box so as to be in electrical communication with at least one other of the plurality of electrical devices. At least one of the electrical devices is connected to the at least one junction box via the at least one exposed electrical connector.

[0006] Preferably, the electrical distribution system also includes at least one conductive path that is configured to transfer electrical energy between two different regions of the vehicle chassis. The at least one conductive path is operatively connected to the at least one junction box such that the at least one electrical connector is an access port at which current may enter, or depart from, the at least one conductive path.

[0007] In a preferred embodiment, the electrical distribution system includes a plurality of junction boxes. The junction boxes are positioned in various regions of the chassis, and conductive paths interconnect the junction boxes. Electrical devices in a particular region of the chassis are connected to the at least one electrical connector of a proximate, i.e., nearby, junction box so as to be in operative electrical communication with at least one other electrical device connected to the electrical distribution system.

[0008] The electrical distribution system facilitates the interconnection of electrical devices by replacing the long and cumbersome wiring harnesses of the prior art; electrical devices can be individually connected to a proximate junction box with a relatively short length of wire, or more than one electrical device can be connected to a proximate junction box with a short and easy-to-handle wiring harness.

[0009] The electrical distribution system preferably includes sensors and microprocessors to monitor the transmission of electrical energy through the electrical distribution system and report fault conditions, such as inadequate signal strength, excessive noise, etc.

[0010] The electrical distribution system preferably contains sufficient conductive paths and sufficient terminals to accommodate, and operatively interconnect, the electrical devices of each of the electrical device combinations that an assembler intends to install in various vehicles. The electrical distribution system is thus a standard, commonized system that can be used without modification in vehicles having different quantities of electrical devices or vehicles having differently-configured electrical devices. Accordingly, a method of coordinating the electrical communication of vehicle electrical devices is also provided.

[0011] The method includes determining a quantity of electrical device combinations for vehicles, each combination having a different quantity of electrical devices or differently-configured electrical devices. The method also includes maintaining an inventory of substantially identical electrical distribution systems each having a plurality of junction boxes and a plurality of conductive paths interconnecting the plurality of junction boxes. The junction boxes each include at least one electrical connector with terminals connected to at least one of the plurality of conductive paths. The electrical distribution systems each include sufficient conductive paths and sufficient terminals to accommodate, and operatively interconnect, the electrical devices of each of the quantity of electrical device combinations without modification.

[0012] A similar distribution system can be employed in a vehicle chassis to transfer signals in nonmechanical forms not limited to electricity. For example, where a nonmechanical signal transmitting device transmits signals using light, then a distribution system can employ optical fibers as a conductive path or medium between the transmitting device and a receiving device.

[0013] The above features and advantages, and other features and advantages, of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings.

[0046] Referring to FIG. 1, a vehicle chassis 10 in accordance with the invention, also referred to as the “rolling platform,” includes a structural frame 11. The structural frame 11 depicted in FIG. 1 comprises a series of interconnected structural elements including upper and lower side structural elements 12 and 14 that comprise a “sandwich”-like construction. Elements 12 and 14 are substantially rigid tubular (or optionally solid), members that extend longitudinally between the front and rear axle areas 16, 18, and are positioned outboard relative to similar elements 20, 22. The front and rear ends of elements 12, 14 are angled inboard, extending toward elements 20 and 22 and connecting therewith prior to entering the axle areas 16, 18. For added strength and rigidity a number of vertical and angled structural elements extend between elements 12, 14, 20 and 22. Similar to the elements 12, 14, 20 and 22, which extend along the left side of the rolling platform 10, a family of structural elements 26, 28, 30 and 32 extend along the right side thereof.

[0047] Lateral structural elements 34, 36 extend between elements 20, 30 and 22, 32, respectively nearer the front axle area 16 and lateral structural elements 38, 40 extend between elements 20, 30 and 22, 32, respectively nearer the rear axle area 18, thereby defining a mid-chassis space 41. The front axle area 16 is defined in and around structural elements 43, 44 at the rear and front, and on the sides by structural elements 46, 48 which may be extensions of the elements 20, 22, 30, 32 or connected therewith. Forward of the front axle area, a forward space is defined between element 44 and elements 50, 52. The rear axle area 18 is defined in and around structural elements 53, 54 at the front and rear, and on the sides by structural elements 56, 58, which may be extensions of the elements 20, 22, 30, 32 or connected therewith. Rearward of the rear axle area 18, a rearward space is defined between element 54 and elements 60, 62. Alternatively, the rear axle area 18 or the rearward space may be elevated relative to the rest of the structural frame 11 if necessary to accommodate an energy conversion system, and the frame may include other elements to surround and protect an energy conversion system. The frame defines a plurality of open spaces between the elements described above. Those skilled in the art will recognize materials and fastening methods suitable for use in the structural frame. For example, the structural elements may be tubular, aluminum, and welded at their respective connections to other structural elements.

[0048] The structural frame 11 provides a rigid structure to which an energy conversion system 67, energy storage system 69, suspension system 71 with wheels 73, 75, 77, 79 (each wheel having a tire 80), steering system 81, and braking system 83 are mounted, as shown in FIGS. 1-3, and is configured to support an attached body 85, as shown in FIG. 4. A person of ordinary skill in the art will recognize that the structural frame 11 can take many different forms, in addition to the cage-like structure of the embodiment depicted in FIGS. 1-3. For example, the structural frame 11 can be a traditional automotive frame having two or more longitudinal structural members spaced a distance apart from each other, with two or more transverse structural members spaced apart from each other and attached to both longitudinal structural members at their ends. Alternatively, the structural frame may also be in the form of a “belly pan,” wherein integrated rails and cross members are formed in sheets of metal or other suitable material, with other formations to accommodate various system components. The structural frame may also be integrated with various chassis components.

[0049] Referring to FIG. 2, a body attachment interface 87 is defined as the sum of all body connection components, i.e., connective elements that function to operably mate a vehicle body to the chassis 10. The body connection components of the preferred embodiment include a plurality of load-bearing body-retention couplings 89 mounted with respect to the structural frame 11 and a single electrical connector 91.

[0050] As shown in FIG. 4, the load-bearing body-retention couplings 89 are engageable with complementary attachment couplings 93 on a vehicle body 85 and function to physically fasten the vehicle body 85 to the chassis 10. Those skilled in the art will recognize that a multitude of fastening and locking elements may be used and fall within the scope of the claimed invention. The load-bearing body-retention couplings 89 are preferably releasably engageable with complementary couplings, though non-releasably engageable couplings such as weld flanges or riveting surfaces may be employed within the scope of the claimed invention. Ancillary fastening elements may be used as lock downs in conjunction with the load-bearing body-retention couplings. Load-bearing surfaces without locking or fastening features on the chassis 10 may be used with the load-bearing body-retention couplings 89 to support the weight of an attached vehicle body 85. In the preferred embodiment, the load-bearing body-retention couplings 89 include support brackets with bolt holes. Rubber mounts (not shown) located on the support brackets dampen vibrations transmitted between the body and the chassis. Alternatively, hard mounts may be employed for body-retention couplings.

[0051] The electrical connector 91 is engageable with a complementary electrical connector 95 on a vehicle body 85. The electrical connector 91 of the preferred embodiment may perform multiple functions, or select combinations thereof. First, the electrical connector 91 may function as an electrical power connector, i.e., it may be configured to transfer electrical energy generated by components on the chassis 10 to a vehicle body 85 or other non-chassis destination. Second, the electrical connector 91 may function as a control signal receiver, i.e., a device configured to transfer non-mechanical control signals from a non-chassis source to controlled systems including the energy conversion system, steering system, and braking system. Third, the electrical connector 91 may function as a feedback signal conduit through which feedback signals are made available to a vehicle driver. Fourth, the electrical connector 91 may function as an external programming interface through which software containing algorithms and data may be transmitted for use by controlled systems. Fifth, the electrical connector may function as an information conduit through which sensor information and other information is made available to a vehicle driver. The electrical connector 91 may thus function as a communications and power “umbilical” port through which all communications between the chassis 10 and an attached vehicle body 85 are transmitted. Electrical connectors include devices configured to operably connect one or more electrical wires with other electrical wires. The wires may be spaced a distance apart to avoid any one wire causing signal interference in another wire operably connected to an electrical connector or for any reason that wires in close proximity may not be desirable.

[0052] If one electrical connector performing multiple functions is not desirable, for example, if a cumbersome wire bundle is required, or power transmission results in control signal interference, the body attachment interface 87 may include a plurality of electrical connectors 91 engageable with a plurality of complementary electrical connectors 95 on a vehicle body 85, with different connectors performing different functions. A complementary electrical connector 95 performs functions complementary to the function of the electrical connector with which it engages, for example, functioning as a control signal transmitter when engaged with a control signal receiver.

[0053] Referring again to FIGS. 1-3, the energy conversion system 67, energy storage system 69, steering system 81, and braking system 83, are configured and positioned on the chassis 10 to minimize the overall vertical height of the chassis 10 and to maintain a substantially horizontal upper chassis face 96. A face of an object is an imaginary surface that follows the contours of the object that face, and are directly exposed to, a particular direction. Thus, the upper chassis face 96 is an imaginary surface that follows the upwardly facing and exposed contours of the chassis frame 11 and systems mounted therein. Matable vehicle bodies have a corresponding lower body face 97 that is an imaginary surface that follows the downwardly facing and exposed contours of the body 85, as shown in FIG. 4.

[0054] Referring again to FIGS. 1-3, the structural frame 11 has a thickness defined as the vertical distance between its highest point (the top of structural element 20) and its lowest point (the bottom of structural element 22). In the preferred embodiment, the structural frame thickness is approximately 11 inches. To achieve a substantially horizontal upper chassis face 96, the energy conversion system 67, energy storage system 69, steering system 81, and braking system 83 are distributed throughout the open spaces and are configured, positioned, and mounted to the structural frame 11 such that the highest point of any of the energy conversion system 67, energy storage system 69, steering system 81, and braking system 83 does not extend or protrude higher than the highest point of the structural frame 11 by an amount more than 50% of the structural frame thickness. Alternatively, the highest point of any of the energy conversion system 67, energy storage system 69, steering system 81, and braking system 83 does not extend or protrude higher than the top of any of the tires 80. Alternatively, the highest point of any of the energy conversion system 67, energy storage system 69, steering system 81, and braking system 83 does not extend or protrude higher than the top of any of the wheels 73, 75, 77, 79. In the context of the present-invention, a tire is not considered part of a wheel. A wheel typically comprises a rim and a wheel disc or nave that connects the rim to a wheel hub, and does not include a mounted tire. A tire is mounted around the periphery of a wheel. The substantially horizontal upper chassis face 96 enables the attached vehicle body 85 to have a passenger area that extends the length of the chassis, unlike prior art bodies that have an engine compartment to accommodate a vertically-protruding internal combustion engine.

[0055] Most of the powertrain load is evenly distributed between the front and rear of the chassis so there is a lower center of gravity for the whole vehicle without sacrificing ground clearance, thereby enabling improved handling while resisting rollover forces.

[0056] Referring again to FIG. 4, the preferred embodiment of the rolling platform 10 is configured such that the lower body face 97 of a matable vehicle body 85 is positioned closely adjacent to the upper chassis face 96 for engagement with the rolling platform 10. The body connection components have a predetermined spatial relationship relative to one another, and are sufficiently positioned, exposed, and unobstructed such that when a vehicle body 85 having complementary connection components (complementary attachment couplings 93 and a complementary electrical connector 95) in the same predetermined spatial relationship as the body connection components is sufficiently positioned relative to the upper chassis face 96 of a chassis 10 of the invention, the complementary connection components are adjacent to corresponding body connection components and ready for engagement, as depicted in FIG. 4. In the context of the present invention, a body connection component having a protective covering is exposed and unobstructed if the protective covering is removable or retractable.

[0057] Each body connection component has a spatial relationship relative to each of the other body connection components that can be expressed, for example, as a vector quantity. Body connection components and complementary connection components have the same predetermined spatial relationship if the vector quantities that describe the spatial relationship between a body connection component and the other body connection components to be engaged also describe the spatial relationship between a corresponding complementary connection component and the other complementary connection components to be engaged. For example, the spatial relationship may be defined as follows: a first body connection component is spaced a distance Ax+By from a reference point; a second body connection component is spaced a distance Cx+Dy from the reference point; a third body connection component is spaced a distance Ex+Fy from the reference point, etc. Corresponding complementary connection components in the same predetermined spatial relationship are spaced in a mirror image relationship in the lower body face, as depicted in FIGS. 4 and 5. A protective covering (not shown) may be employed to protect any of the body connection components.

[0058] The body connection components and the complementary connection components are preferably adjacent without positional modification when a vehicle body 85 is sufficiently positioned relative to a chassis 10 of the invention; however, in the context of the present invention, the body connection components may be movable relative to each other within a predetermined spatial relationship to accommodate build tolerances or other assembly issues. For example, an electrical connector may be positioned and operably connected to a signal-carrying cable. The cable may be fixed relative to the structural frame at a point six inches from the electrical connector. The electrical connector will thus be movable within six inches of the fixed point on the cable. A body connection component is considered adjacent to a complementary connection component if one or both are movable within a predetermined spatial relationship so as to be in contact with each other.

[0059] Referring to FIG. 5, the body-attachment interface of the claimed invention enables compatibility between the chassis 10 and different types of bodies 85, 85′, 85″ having substantially different designs. Bodies 85, 85′, 85″ having a common base 98 with complementary attachment couplings 93 and complementary electrical connectors 95 in the same predetermined spatial relationship with one another as the predetermined spatial relationship between body connection components on the body-attachment interface 87, are each matable with the chassis 10 by positioning the body 85, 85′, 85″ relative to the chassis 10 such that each complementary attachment coupling 93 is adjacent to a load-bearing body-retention coupling 89, and the complementary electrical connector 95 is adjacent to the electrical connector 91. Preferably, all bodies and chassis comply with this common, standardized interface system, thereby facilitating compatibility between a wide array of different body types and styles and a single chassis design. The substantially horizontal upper chassis face 96 also facilitates compatibility between the rolling platform 10 and a multitude of differently-configured body styles. The common base 98 functions as a body structural unit and forms the lower body face 97 in the embodiment depicted. FIG. 5 schematically depicts a sedan 85, a van 85′, and a pickup truck 85″ each having a common base 98.

[0060] The body connection components are preferably sufficiently exposed at a chassis face to facilitate attachment to complementary connection components on a matable vehicle body. Similarly, complementary connection components on a matable vehicle body are sufficiently exposed at a body face to facilitate attachment to body connection components on a vehicle chassis. The body connection components are preferably located at or above the upper chassis face for engagement with complementary connection components located at or below a lower body face.

[0061] A connection device may be employed to engage or operably connect a body connection component with a distant complementary connection component, in the situation where a vehicle body does not have complementary connection components in the same predetermined spatial relationship as the body connection components on a vehicle chassis. For example, a cable having two connectors, one connector engageable with the electrical connector on a body attachment interface and the other connector engageable with a complementary connector on a matable vehicle body, may be used to operably connect the electrical connector and the complementary connector.

[0062] The bodies 85, 85′, 85″ shown schematically in FIG. 5 each use all of the body connection components on the vehicle chassis 10. However, within the scope of the claimed invention, a chassis may have more body connection components than are actually mated with a vehicle body. For example, a chassis may have ten load-bearing body-retention couplings, and be matable with a body that engages only five of the ten load-bearing body-retention couplings. Such an arrangement is particularly useful when an attachable body is of a different size than the chassis. For example, a matable body may be smaller than a chassis. Similarly, and within the scope of the claimed invention, a body may be modular such that separate body components are independently connected to the vehicle chassis by the load-bearing body-retention couplings.

[0063] A body may have more complementary connection components than are engageable with the body connection components of a particular chassis. Such an arrangement may be employed to enable a particular body to be matable to multiple chassis each having a different predetermined spatial relationship among its body connection components.

[0064] The load-bearing body-retention couplings 89 and the electrical connector 91 are preferably releasably engageable without damage to either an attached body 85 or the chassis 10, thereby enabling removal of one body 85 from the chassis 10 and installation of a different body 85′, 85″ on the chassis 10.

[0065] In the preferred embodiment, the body-attachment interface 87 is characterized by the absence of any mechanical control signal-transmission linkages and any couplings for attaching mechanical control signal-transmission linkages. Mechanical control linkages, such as steering columns, limit the compatibility between a chassis and bodies of different configurations.

[0066] Referring to FIG. 1, the steering system 81 is housed in the front axle area 16 and is operably connected to the front wheels 73, 75. Preferably, the steering system 81 is responsive to non-mechanical control signals. In the preferred embodiment, the steering system 81 is by-wire. A by-wire system is characterized by control signal transmission in electrical form. In the context of the present invention, “by-wire” systems, or systems that are controllable “by-wire,” include systems configured to receive control signals in electronic form via a control signal receiver on the body attachment interface 87, and respond in conformity to the electronic control signals.

[0067] Referring to FIG. 6, the by-wire steering system 81 of the preferred embodiment includes a steering control unit 99, and a steering actuator 100. Sensors 101 are located on the chassis 10 and transmit sensor signals 102 carrying information concerning the state or condition of the chassis 10 and its component systems. The sensors 101 may include position sensors, velocity sensors, acceleration sensors, pressure sensors, force and torque sensors, flow meters, temperature sensors, etc. The steering control unit 99 receives and processes sensor signals 102 from the sensors 101 and electrical steering control signals 103 from the electrical connector 91, and generates steering actuator control signals 104 according to a stored algorithm. A control unit typically includes a microprocessor, ROM and RAM and appropriate input and output circuits of a known type for receiving the various input signals and for outputting the various control commands to the actuators. Sensor signals 102 may include yaw rate, lateral acceleration, angular wheel velocity, tie-rod force, steering angle, chassis velocity, etc.

[0068] The steering actuator 100 is operably connected to the front wheels 73, 75 and configured to adjust the steering angle of the front wheels 73, 75 in response to the steering actuator control signals 104. Actuators in a by-wire system transform electronic control signals into a mechanical action or otherwise influence a system's behavior in response to the electronic control signals. Examples of actuators that may be used in a by-wire system include electromechanical actuators such as electric servomotors, translational and rotational solenoids, magnetorheological actuators, electrohydraulic actuators, and electrorheological actuators. Those skilled in the art will recognize and understand mechanisms by which the steering angle is adjusted. In the preferred embodiment, the steering actuator 100 is an electric drive motor configured to adjust a mechanical steering rack.

[0069] Referring again to FIG. 6, the preferred embodiment of the chassis 10 is configured such that it is steerable by any source of compatible electrical steering control signals 103 connected to the electrical connector 91. FIG. 6 depicts a steering transducer 105 located on an attached vehicle body 85 and connected to a complementary electrical connector 95. Transducers convert the mechanical control signals of a vehicle driver to non-mechanical control signals. When used with a by-wire system, transducers convert the mechanical control signals to electrical control signals usable by the by-wire system. A vehicle driver inputs control signals in mechanical form by turning a wheel, depressing a pedal, pressing a button, or the like. Transducers utilize sensors, typically position and force sensors, to convert the mechanical input to an electrical signal. In the preferred embodiment, a +/−20 degree slide mechanism is used for driver input, and an optical encoder is used to read input rotation.

[0070] The complementary electrical connector 95 is coupled with the electrical connector 91 of the body attachment interface 87. The steering transducer 105 converts vehicle driver-initiated mechanical steering control signals 106 to electrical steering control signals 103 which are transmitted via the electrical connector 91 to the steering control unit 99. In the preferred embodiment, the steering control unit 99 generates steering feedback signals 107 for use by a vehicle driver and transmits the steering feedback signals 107 through the electrical connector 91. Some of the sensors 101 monitor linear distance movement of the steering rack and vehicle speed. This information is processed by the steering control unit 99 according to a stored algorithm to generate the steering feedback signals 107. A torque control motor operably connected to the slide mechanism receives the steering feedback signals 107 and is driven in the opposite direction of the driver's mechanical input.

[0071] In the context of the present invention, a “by-wire” system may be an actuator connected directly to an electrical connector in the body attachment interface. An alternative by-wire steering system 81′ within the scope of the claimed invention is depicted schematically in FIG. 7, wherein like reference numbers refer to like components from FIG. 6. A steering actuator 100 configured to adjust the steering angle of the front wheels 73, 75 is connected directly to the electrical connector 91. In this embodiment, a steering control unit 99′ and a steering transducer 105 may be located in an attached vehicle body 85. The steering transducer 105 would transmit electrical steering control signals 103 to the steering control unit 99′, and the steering control unit 99′ would transmit steering actuator control signals 104 to the steering actuator 100 via the electrical connector 91. Sensors 101 positioned on the chassis 10 transmit sensor signals 102 to the steering control unit 99′ via the electrical connector 91 and the complementary electrical connector 95.

[0072] Examples of steer-by-wire systems are described in U.S. Pat. No. 6,176,341, issued Jan. 23, 2001 to Ansari; U.S. Pat. No. 6,208,923, issued Mar. 27, 2001 to Hommel; U.S. Pat. No. 6,219,604, issued Apr. 17, 2001 to Dilger, et al.; U.S. Pat. No. 6,318,494, issued Nov. 20, 2001 to Pattok; U.S. Pat. No. 6,370,460, issued Apr. 9, 2002 to Kaufmann, et al.; and U.S. Pat. No. 6,394,218, issued May 28, 2002 to Heitzer; which are hereby incorporated by reference in their entireties.

[0073] The steer-by-wire system described in U.S. Pat. No. 6,176,341 includes a position sensor for sensing angular position of a road wheel, a hand-operated steering wheel for controlling direction of the road wheel, a steering wheel sensor for sensing position of the steering wheel, a steering wheel actuator for actuating the hand-operated steering wheel, and a steering control unit for receiving the sensed steering wheel position and the sensed road wheel position and calculating actuator control signals, preferably including a road wheel actuator control signal and a steering wheel actuator control signal, as a function of the difference between the sensed road wheel position and the steering wheel position. The steering control unit commands the road wheel actuator to provide controlled steering of the road wheel in response to the road wheel actuator control signal. The steering control unit further commands the steering wheel actuator to provide feedback force actuation to the hand-operated steering wheel in response to the steering wheel control signal. The road wheel actuator control signal and steering wheel actuator control signal are preferably scaled to compensate for difference in gear ratio between the steering wheel and the road wheel. In addition, the road wheel actuator control signal and steering wheel actuator control signal may each have a gain set so that the road wheel control actuator signal commands greater force actuation to the road wheel than the feedback force applied to the steering wheel.

[0074] The steer-by-wire system described in U.S. Pat. No. 6,176,341 preferably implements two position control loops, one for the road wheel and one for the hand wheel. The position feedback from the steering wheel becomes a position command input for the road wheel control loop and the position feedback from the road wheel becomes a position command input for the steering wheel control loop. A road wheel error signal is calculated as the difference between the road wheel command input (steering wheel position feedback) and the road wheel position. Actuation of the road wheel is commanded in response to the road wheel error signal to provide controlled steering of the road wheel. A steering wheel error signal is calculated as the difference between the steering wheel position command (road wheel position feedback) and the steering wheel position. The hand-operated steering wheel is actuated in response to the steering wheel error signal to provide force feedback to the hand-operated steering wheel.

[0075] The steering control unit of the '341 system could be configured as a single processor or multiple processors and may include a general-purpose microprocessor-based controller, that may include a commercially available off-the-shelf controller. One example of a controller is Model No. 87C196CA microcontroller manufactured and made available from Intel Corporation of Delaware. The steering control unit preferably includes a processor and memory for storing and processing software algorithms, has a clock speed of 16 MHz, two optical encoder interfaces to read position feedbacks from each of the actuator motors, a pulse width modulation output for each motor driver, and a 5-volt regulator.

[0076] U.S. Pat. No. 6,370,460 describes a steer-by-wire control system comprising a road wheel unit and a steering wheel unit that operate together to provide steering control for the vehicle operator. A steering control unit may be employed to support performing the desired signal processing. Signals from sensors in the road wheel unit, steering wheel unit, and vehicle speed are used to calculate road wheel actuator control signals to control the direction of the vehicle and steering wheel torque commands to provide tactile feedback to the vehicle operator. An Ackerman correction may be employed to adjust the left and right road wheel angles correcting for errors in the steering geometry to ensure that the wheels will track about a common turn center.

[0077] Referring again to FIG. 1, a braking system 83 is mounted to the structural frame 11 and is operably connected to the wheels 73, 75, 77, 79. The braking system is configured to be responsive to non-mechanical control signals. In the preferred embodiment, the braking system 83 is by-wire, as depicted schematically in FIG. 8, wherein like reference numbers refer to like components from FIGS. 6 and 7. Sensors 101 transmit sensor signals 102 carrying information concerning the state or condition of the chassis 10 and its component systems to a braking control unit 108. The braking control unit 108 is connected to the electrical connector 91 and is configured to receive electrical braking control signals 109 via the electrical connector 91. The braking control unit 108 processes the sensor signals 102 and the electrical braking control signals 109 and generates braking actuator control signals 110 according to a stored algorithm. The braking control unit 108 then transmits the braking actuator control signals 110 to braking actuators 111, 112, 113, 114 which act to reduce the angular velocity of the wheels 73, 75, 77, 79. Those skilled in the art will recognize the manner in which the braking actuators 111, 112, 113, 114 act on the wheels 73, 75, 77, 79. Typically, actuators cause contact between friction elements, such as pads and disc rotors. Optionally, an electric motor may function as a braking actuator in a regenerative braking system.

[0078] The braking control unit 108 may also generate braking feedback signals 115 for use by a vehicle driver and transmit the braking feedback signals 115 through the electrical connector 91. In the preferred embodiment, the braking actuators 111, 112, 113, 114 apply force through a caliper to a rotor at each wheel. Some of the sensors 101 measure the applied force on each caliper. The braking control unit 108 uses this information to ensure synchronous force application to each rotor.

[0079] Referring again to FIG. 8, the preferred embodiment of the chassis 10 is configured such that the braking system is responsive to any source of compatible electrical braking control signals 109. A braking transducer 116 may be located on an attached vehicle body 85 and connected to a complementary electrical connector 95 coupled with the electrical connector 91. The braking transducer 116 converts vehicle driver-initiated mechanical braking control signals 117 into electrical form and transmits the electrical braking control signals 109 to the braking control unit via the electrical connector 91. In the preferred embodiment, the braking transducer 116 includes two hand-grip type assemblies. The braking transducer 116 includes sensors that measure both the rate of applied pressure and the amount of applied pressure to the hand-grip assemblies, thereby converting mechanical braking control signals 117 to electrical braking control signals 109. The braking control unit 108 processes both the rate and amount of applied pressure to provide both normal and panic stopping.

[0080] An alternative brake-by-wire system 83′ within the scope of the claimed invention is depicted in FIG. 9, wherein like reference numbers refer to like components from FIGS. 6-8. The braking actuators 111, 112, 113, 114 and sensors 101 are connected directly to the electrical connector 91. In this embodiment, a braking control unit 108′ may be located in an attached vehicle body 85. A braking transducer 116 transmits electrical braking control signals 109 to the braking control unit 108′, and the braking control unit 108′ transmits braking actuator signals 109 to the braking actuators 111, 112, 113, 114 via the electrical connector 91.

[0081] Examples of brake-by-wire systems are described in U.S. Pat. No. 5,366,281, issued Nov. 22, 2994 to Littlejohn; U.S. Pat. No. 5,823,636, issued Oct. 20, 1998 to Parker, et al.; U.S. Pat. No. 6,305,758, issued Oct. 23, 2001 to Hageman; and U.S. Pat. No. 6,390,565, issued May 21, 2002 to Riddiford, et al.; which are hereby incorporated by reference in their entireties.

[0082] The system described in U.S. Pat. No. 5,366,281 includes an input device for receiving mechanical braking control signals, a brake actuator and a control unit coupled to the input device and the brake actuator. The control unit receives brake commands, or electrical braking control signals, from the input device and provides actuator commands, or braking actuator control signals, to control current and voltage to the brake actuator. When a brake command is first received from the input device, the control unit outputs, for a first predetermined time period, a brake torque command to the brake actuator commanding maximum current to the actuator. After the first predetermined time period, the control unit outputs, for a second predetermined time period, a brake torque command to the brake actuator commanding voltage to the actuator responsive to the brake command and a first gain factor. After the second predetermined time period, the control unit outputs the brake torque command to the brake actuator commanding current to the actuator responsive to the brake command and a second gain factor, wherein the first gain factor is greater than the second gain factor and wherein brake initialization is responsive to the brake input.

[0083] U.S. Pat. No. 6,390,565 describes a brake-by-wire system that provides the capability of both travel and force sensors in a braking transducer connected to a brake apply input member such as a brake pedal and also provides redundancy in sensors by providing the signal from a sensor responsive to travel or position of the brake apply input member to a first control unit and the signal from a sensor responsive to force applied to a brake apply input member to a second control unit. The first and second control units are connected by a bi-directional communication link whereby each controller may communicate its received one of the sensor signals to the other control unit. In at least one of the control units, linearized versions of the signals are combined for the generation of first and second brake apply command signals for communication to braking actuators. If either control unit does not receive one of the sensor signals from the other, it nevertheless generates its braking actuator control signal on the basis of the sensor signal provided directly to it. In a preferred embodiment of the system, a control unit combines the linearized signals by choosing the largest in magnitude.

[0084] Referring again to FIG. 1, the energy storage system 69 stores energy that is used to propel the chassis 10. For most applications, the stored energy will be in chemical form. Examples of energy storage systems 69 include fuel tanks and electric batteries. In the embodiment shown in FIG. 1, the energy storage system 69 includes two compressed gas cylinder storage tanks 121 (5,000 psi, or 350 bars) mounted within the mid-chassis space 41 and configured to store compressed hydrogen gas. Employing more than two compressed gas cylinder storage tanks may be desirable to provide greater hydrogen storage capacity. Instead of compressed gas cylinder storage tanks 121, an alternate form of hydrogen storage may be employed such as metal or chemical hydrides. Hydrogen generation or reforming may also be used.

[0085] The energy conversion system 67 converts the energy stored by the energy storage system 69 to mechanical energy that propels the chassis 10. In the preferred embodiment, depicted in FIG. 1, the energy conversion system 67 includes a fuel cell stack 125 located in the rear axle area 18, and an electric traction motor 127 located in the front axle area 16. The fuel cell stack 125 produces a continuously available power of 94 kilowatts. Fuel cell systems for vehicular use are described in U.S. Pat. No. 6,195,999, issued Mar. 6, 2001 to Arnold, et al.; U.S. Pat. No. 6,223,843, issued May 1, 2001 to O'Connell, et al.; U.S. Pat. No. 6,321,145, issued Nov. 20, 2001 to Rajashekara; and U.S. Pat. No. 6,394,207, issued May 28, 2002 to Skala; which are hereby incorporated by reference in their entireties.

[0086] The fuel cell stack 125 is operably connected to the compressed gas cylinder storage tanks 121 and to the traction motor 127. The fuel cell stack 125 converts chemical energy in the form of hydrogen from the compressed gas cylinder storage tanks 121 into electrical energy, and the traction motor 127 converts the electrical energy to mechanical energy, and applies the mechanical energy to rotate the front wheels 73, 75. Optionally, the fuel cell stack 125 and traction motor 127 are switched between the front axle area 16 and rear axle area 18. Optionally, the energy conversion system includes an electric battery (not shown) in hybrid combination with the fuel cell to improve chassis acceleration. Other areas provided between the structural elements are useful for housing other mechanisms and systems for providing the functions typical of an automobile as shown in FIGS. 2 and 3. Those skilled in the art will recognize other energy conversion systems 67 that may be employed within the scope of the present invention.

[0087] The energy conversion system 67 is configured to respond to non-mechanical control signals. The energy conversion system 67 of the preferred embodiment is controllable by-wire, as depicted in FIG. 10. An energy conversion system control unit 128 is connected to the electrical connector 91 from which it receives electrical energy conversion system control signals 129, and sensors 101 from which it receives sensor signals 102 carrying information about various chassis conditions. In the preferred embodiment, the information conveyed by the sensor signals 102 to the energy conversion system control unit 128 includes chassis velocity, electrical current applied, rate of acceleration of the chassis, and motor shaft speed to ensure smooth launches and controlled acceleration. The energy conversion system control unit 128 is connected to an energy conversion system actuator 130, and transmits energy conversion system actuator control signals 131 to the energy conversion system actuator 130 in response to the electrical energy conversion system control signals 129 and sensor signals 102 according to a stored algorithm. The energy conversion system actuator 130 acts on the fuel cell stack 125 or traction motor 127 to adjust energy output. Those skilled in the art will recognize the various methods by which the energy conversion system actuator 130 may adjust the energy output of the energy conversion system. For example, a solenoid may alternately open and close a valve that regulates hydrogen flow to the fuel cell stack. Similarly, a compressor that supplies oxygen (from air) to the fuel cell stack may function as an actuator, varying the amount of oxygen supplied to the fuel cell stack in response to signals from the energy conversion system control unit.

[0088] An energy conversion system transducer 132 may be located on a vehicle body 85 and connected to a complementary electrical connector 95 engaged with the electrical connector 91. The energy conversion system transducer 132 is configured to convert mechanical energy conversion system control signals 133 to electrical energy conversion system control signals 129.

[0089] In another embodiment of the invention, as shown schematically in FIG. 11, wherein like reference numbers refer to like components from FIGS. 6-10, wheel motors 135, also known as wheel hub motors, are positioned at each of the four wheels 73, 75, 77, 79. Optionally, wheel motors 135 may be provided at only the front wheels 73, 75 or only the rear wheels 77, 79. The use of wheel motors 135 reduces the height of the chassis 10 compared to the use of traction motors, and therefore may be desirable for certain uses.

[0090] Referring again to FIG. 2, a conventional heat exchanger 137 and electric fan system 139, operably connected to the fuel cell stack 125 to circulate coolant for waste heat rejection, is carried in an opening that exists between the rear axle area 18 and the structural elements 54, 60. The heat exchanger 137 is set at an inclined angle to reduce its vertical profile, but to provide adequate heat rejection it also extends slightly above the top of elements 12, 26 (as seen in FIG. 4). Although the fuel cell stack 125, heat exchanger 137 and electric fan system 139 extend above the structural elements, their protrusion into the body pod space is relatively minor when compared to the engine compartment requirements of a conventionally designed automobile, especially when the chassis height of the preferred embodiment is approximately a mere 15 inches (28 centimeters). Optionally, the heat exchanger 137 is packaged completely within the chassis' structure with airflow routed through channels (not shown).

[0091] Referring again to FIG. 1, the suspension system 71 is mounted to the structural frame 11 and is connected to four wheels 73, 75, 77, 79. Those skilled in the art will understand the operation of a suspension system, and recognize that a multitude of suspension system types may be used within the scope of the claimed invention. The suspension system 71 of the preferred embodiment of the invention is electronically controlled, as depicted schematically in FIG. 12.

[0092] Referring to FIG. 12, the behavior of the electronically controlled suspension system 71 in response to any given road input is determined by a suspension control unit 141. Sensors 101 located on the chassis 10 monitor various conditions such as vehicle speed, angular wheel velocity, and wheel position relative to the chassis 10. The sensors 101 transmit the sensor signals 102 to the suspension control unit 141. The suspension control unit 141 processes the sensor signals 102 and generates suspension actuator control signals 142 according to a stored algorithm. The suspension control unit 141 transmits the suspension actuator control signals 142 to four suspension actuators 143, 144, 145, 146. Each suspension actuator 143, 144, 145, 146 is operably connected to a wheel 73, 75, 77, 79 and determines, in whole or in part, the position of the wheel 73, 75, 77, 79 relative to the chassis 10. The suspension actuators of the preferred embodiment are variable-force, real time, controllable dampers. The suspension system 71 of the preferred embodiment is also configured such that chassis ride height is adjustable. Separate actuators may be used to vary the chassis ride height.

[0093] In the preferred embodiment, the suspension control unit 141 is programmable and connected to the electrical connector 91 of the body-attachment interface 87. A vehicle user is thus able to alter suspension system 71 characteristics by reprogramming the suspension control unit 141 with suspension system software 147 via the electrical connector 91.

[0094] In the context of the claimed invention, electronically-controlled suspension systems include suspension systems without a suspension control unit located on the chassis 10. Referring to FIG. 13, wherein like reference numbers are used to reference like components from FIG. 12, suspension actuators 143, 144, 145, 146 and suspension sensors 101 are connected directly to the electrical connector 91. In such an embodiment, a suspension control unit 141′ located on an attached vehicle body 85 can process sensor signals 102 transmitted through the electrical connector 91, and transmit suspension actuator control signals 142 to the suspension actuators 143, 144, 145, 146 via the electrical connector 91.

[0095] Examples of electronically controlled suspension systems are described in U.S. Pat. No. 5,606,503, issued Feb. 25, 1997 to Shal, et al.; U.S. Pat. No. 5,609,353, issued Mar. 11, 1997 to Watson; and U.S. Pat. No. 6,397,134, issued May 28, 2002 to Shal, et al.; which are hereby incorporated by reference in their entireties.

[0096] U.S. Pat. No. 6,397,134 describes an electronically controlled suspension system that provides improved suspension control through steering crossover events. In particular, the system senses a vehicle lateral acceleration and a vehicle steering angle and stores, for each direction of sensed vehicle lateral acceleration, first and second sets of enhanced suspension actuator control signals for the suspension actuators of the vehicle. Responsive to the sensed vehicle lateral acceleration and sensed vehicle steering angle, the system applies the first set of enhanced actuator control signals to the suspension actuators if the sensed steering angle is in the same direction as the sensed lateral acceleration and alternatively applies the second set of enhanced actuator control signals to the suspension actuators if the sensed steering angle is in the opposite direction as the sensed lateral acceleration.

[0097] U.S. Pat. No. 5,606,503 describes a suspension control system for use in a vehicle including a suspended vehicle body, four un-suspended vehicle wheels, four variable force actuators mounted between the vehicle body and wheels, one of the variable force actuators at each corner of the vehicle, and a set of sensors providing sensor signals indicative of motion of the vehicle body, motion of the vehicle wheels, a vehicle speed and an ambient temperature. The suspension control system comprises a microcomputer control unit including: means for receiving the sensor signals; means, responsive to the sensor signals, for determining an actuator demand force for each actuator; means, responsive to the vehicle speed, for determining a first signal indicative of a first command maximum; means, responsive to the ambient temperature, for determining a second signal indicative of a second command maximum; and means for constraining the actuator demand force so that it is no greater than a lesser of the first and second command maximums.

[0098] Electrically conductive wires (not shown) are used in the preferred embodiment to transfer signals between the chassis 10 and an attached body 85, and between transducers, control units, and actuators. Those skilled in the art will recognize that other non-mechanical means of sending and receiving signals between a body and a chassis, and between transducers, control units, and actuators may be employed and fall within the scope of the claimed invention. Other non-mechanical means of sending and receiving signals include radio waves and fiber optics.

[0099] The by-wire systems are networked in the preferred embodiment, in part to reduce the quantity of dedicated wires connected to the electrical connector 91. A serial communication network is described in U.S. Pat. No. 5,534,848, issued Jul. 9, 1996 to Steele, et al., which is hereby incorporated by reference in its entirety. An example of a networked drive-by-wire system is described in U.S. patent application Publication No. US 2001/0029408, Ser. No. 09/775,143, which is hereby incorporated by reference in its entirety. Those skilled in the art will recognize various networking devices and protocols that may be used within the scope of the claimed invention, such as SAE J1850 and CAN (“Controller Area Network”). A TTP (“Time Triggered Protocol”) network is employed in the preferred embodiment of the invention for communications management.

[0100] Some of the information collected by the sensors 101, such as chassis velocity, fuel level, and system temperature and pressure, is useful to a vehicle driver for operating the chassis and detecting system malfunctions. As shown in FIG. 14, the sensors 101 are connected to the electrical connector 91 through a chassis computer 153. Sensor signals 102 carrying information are transmitted from the sensors 101 to the chassis computer 153, which processes the sensor signals 102 according to a stored algorithm. The chassis computer 153 transmits the sensor signals 102 to the electrical connector 91 when, according to the stored algorithm, the sensor information is useful to the vehicle driver. For example, a sensor signal 102 carrying temperature information is transmitted to the electrical connector 91 by the chassis computer 153 when the operating temperature of the chassis 10 is unacceptably high. A driver-readable information interface 155 may be attached to a complementary electrical connector 95 coupled with the electrical connector 91 and display the information contained in the sensor signals 102. Driver-readable information interfaces include, but are not limited to, gauges, meters, LED displays, and LCD displays. The chassis may also contain communications systems, such as antennas and telematics systems, that are operably connected to an electrical connector in the body-attachment interface and configured to transmit information to an attached vehicle body.

[0101] One control unit may serve multiple functions. For example, as shown in FIG. 15, a master control unit 159 functions as the steering control unit, braking control unit, suspension control unit, and energy conversion system control unit.

[0102] Referring again to FIG. 15, the energy conversion system 67 is configured to transmit electrical energy 160 to the electrical connector 91 to provide electric power for systems located on an attached vehicle body, such as power windows, power locks, entertainment systems, heating, ventilating, and air conditioning systems, etc. Optionally, if the energy storage system 69 includes a battery, then the battery may be connected to the electrical connector 91. In the preferred embodiment, the energy conversion system 67 includes a fuel cell stack that generates electrical energy and is connected to the electrical connector 91.

[0103] FIG. 16 shows a chassis 10 with rigid covering, or “skin,” 161 and an electrical connector or coupling 91 that functions as an umbilical port. The rigid covering 161 may be configured to function as a vehicle floor, which is useful if an attached vehicle body 85 does not have a lower surface. In FIG. 17, a similarly equipped chassis 10 is shown with an optional vertical fuel cell stack 125. The vertical fuel cell stack 125 protrudes significantly into the body pod space which is acceptable for some applications. The chassis 10 also includes a manual parking brake interface 162 that may be necessary for certain applications and therefore is also optionally used with other embodiments.

[0104] FIG. 18 depicts an embodiment of the invention that may be advantageous in some circumstances. The energy conversion system 67 includes an internal combustion engine 167 with horizontally-opposed cylinders, and a transmission 169. The energy storage system 69 includes a gasoline tank 171.

[0105] FIG. 19 depicts an embodiment of the invention wherein the steering system 81 has mechanical control linkages including a steering column 173. Passenger seating attachment couplings 175 are present on the body attachment interface 87, allowing the attachment of passenger seating assemblies to the chassis 10.

[0106] FIGS. 20 and 20a depict a chassis 10 within the scope of the invention and a body 85 each having multiple electrical connectors 91 and multiple complementary electrical connectors 95, respectively. For example, a first electrical connector 91 may be operably connected to the steering system and function as a control signal receiver. A second electrical connector 91 may be operably connected to the braking system and function as a control signal receiver. A third electrical connector 91 may be operably connected to the energy conversion system and function as a control signal receiver. A fourth electrical connector 91 may be operably connected to the energy conversion system and function as an electrical power connector. Four multiple wire in-line connectors and complementary connectors are used in the embodiment shown in FIGS. 20 and 20a. FIG. 20a depicts an assembly process for attaching corresponding connectors 91, 95.

[0107] Referring to FIG. 21, a further embodiment of the claimed invention is depicted. The chassis 10 has a rigid covering 161 and a plurality of passenger seating attachment couplings 175. A driver-operable control input device 177 containing a steering transducer, a braking transducer, and an energy conversion system transducer, is operably connected to the steering system, braking system, and energy conversion system by wires 179 and movable to different attachment points.

[0108] The embodiment depicted in FIG. 21 enables bodies of varying designs and configurations to mate with a common chassis design. A vehicle body without a lower surface but having complementary attachment couplings is matable to the chassis 10 at the load-bearing body retention couplings 89. Passenger seating assemblies may be attached at passenger seating attachment couplings 175.

[0109] Referring to FIG. 22, wherein like reference numbers refer to like components from FIGS. 1-21, a vehicle chassis 10g forms a portion of a vehicle and includes an electrical distribution system 180. The electrical distribution system 180 has four junction boxes 184A-D that are spaced a distance apart from one another and mounted with respect to the structural frame (not shown) of the vehicle chassis 10g. The junction boxes 184A-D each include at least one electrical connector (not shown).

[0110] The electrical distribution system 180 also includes conduits 188 that contain wires (not shown) that extend between, and operatively interconnect, the junction boxes 184A-D such that the at least one electrical connector of each junction box 184A-D is an access port at which current may enter, or depart from, at least one of the wires in the conduit 188. The wires function as conductive paths that transfer electrical energy, including electrical signals, between different regions of the vehicle chassis 10g.

[0111] The vehicle chassis 10g also includes a selection and combination of electrical devices. Electrical devices include steering actuators 100′, 100″ that partially form the steering system; braking actuators 111′, 112′, 113′, 114′ that partially form the braking system; electric traction motor 127′, fuel cell stack 125′, and wheel motors 135′ that partially form the energy conversion system; and a battery pack 200 forming a portion of the energy storage system. Other electrical devices include cooling fan 139′ and heating, ventilating and air condition unit 202. A master control unit 159′ is operatively connected to the electrical connector 91′ through which it is configured to receive control signals from a vehicle body (not shown) mated with the chassis 10g.

[0112] The electrical devices include electrical transmitting devices that produce electrical energy or electrical signals. The electrical devices also include electrical receiving devices that receive electrical energy from an electrical transmitting device and convert the electrical energy into another form of energy, or that receive and respond to electrical signals from an electrical transmitting device. An electrical receiving device is often distant from an electrical transmitting device from which it is configured to receive electrical energy or signals. The electrical distribution system 180 facilitates the transmission of electrical energy and signals from electrical transmitting devices to electrical receiving devices. The vehicle chassis electrical devices are connected to the electrical distribution system 180 via the electrical connectors of the junction boxes 184A-D so that various electrical transmitting devices are in operative electrical communication with electrical receiving devices.

[0113] More specifically, the fuel cell stack 125′ and the battery pack 200 are electrical transmitting devices that are in electrical communication with, and transmit electrical energy to, various electrical receiving devices, including the traction motor 127′, the wheel motors 135′, the steering actuators 100′, 100″, braking actuators 111′, 112′, 113′, 114′, the cooling fan 139′, and the heating, ventilating and air conditioning unit 202. The master control unit 159′ is an electrical transmitting device that is in electrical communication with, and sends electrical signals to, the actuators 100′, 100″, 111′, 112′, 113′, 114′, and the heating, ventilating and air conditioning unit 202. Sensors 101 are electrical transmitting devices that are in electrical communication with, and transmit electrical signals to, the master control unit 159′.

[0114] The battery pack 200 is in hybrid combination with the fuel cell stack 125′; thus, in addition to producing and transmitting electrical energy to electrical receiving devices when the fuel cell stack 125′ cannot produce sufficient electrical current to satisfy electrical demands, the battery pack 200 is also an electrical receiving device, receiving electrical energy from the fuel cell stack 125′ and storing the energy in chemical form.

[0115] The electrical distribution system 180 enables the use of small wiring harnesses 192A-D that are shorter in length and significantly less cumbersome than large wiring harnesses typically employed in the prior art. Each small wiring harness 192A-D is used to operatively connect some of the electrical devices to a proximate junction box 184A-D via an electrical connector 196 that is engaged with the at least one electrical connector on the proximate junction box 184A-D.

[0116] Referring to FIG. 23, wherein like reference numbers refer to like components from FIG. 22, vehicle chassis 10g′ includes an alternative embodiment of the electrical distribution system 180′. Junction boxes 184A′, 184B′, 184C′, 184D′ each include a plurality of electrical connectors (not shown) to provide multiple access ports to the electrical distribution system 180′. Each of the electrical devices is operatively connected to a proximate junction box 184A′-D′ via a wire 204 and a connector 208 that is engaged with one of the electrical connectors on the proximate junction box 184A′-D′. The steering actuator 100′″ is a pre-assembled module that includes a wire 204 operatively connected at one end to the steering actuator 100′″ and operatively connected at the other end to an electrical connector 208 that is engaged with an electrical connector on junction box 184D.

[0117] Referring to FIG. 24, wherein like reference numbers refer to like components from FIGS. 22 and 23, exemplary junction box 184D′ is schematically depicted. Junction box 184D′ includes exposed electrical connectors 212 engageable with complementary electrical connectors 208. The electrical connectors 212 include pins 220. Each of the pins 220 is connected to at least one other pin by a conductive path. Thus, each pin 220 serves as a terminal for the at least one conductive path to which it is connected. Wires 216 act as conductive paths that connect some of the pins 220 to pins in at least one of the other junction boxes 184A′, 184B′, 184C′ of FIG. 23. Other wires 222 act as conductive paths that operatively interconnect only pins 220 within a single junction box 184D′. For clarity, only exemplary wires 216, 222 are depicted in FIG. 24.

[0118] Those skilled in the art will recognize a variety of conductive elements, such as wires, flexible printed circuit elements, printed circuit boards, etc, that may be employed within the scope of the claimed invention to at least partially form a conductive path. Within the scope of the claimed invention, a conductive path may or may not comprise more than one conductive element. Furthermore, within the scope of the claimed invention, a conductive path may or may not include switch elements such as relays so that the conductive path is selectively interruptible.

[0119] Branched connections 224 may be employed to operatively connect two or more pins 220 to a single wire 216. Those skilled in the art will recognize multiple techniques and devices that may be used to form a branched connection within the scope of the claimed invention, including bus bars, printed circuit boards, wire splices, etc. Within the scope of the claimed invention, a wire 216, 222 may carry electrical power, electrical signals, or both.

[0120] In the context of the present invention, an “electrical distribution system” includes at least one junction box having a plurality of terminals and at least one conductive path that interconnects at least two of the terminals. The at least one conductive path of an “electrical distribution system” includes conductive paths that are routed within a single junction box, such as wires 222, and conductive paths that interconnect terminals of two or more spaced-apart junction boxes, such as wires 216. An “electrical distribution system” does not include conductive elements providing any part of a conductive path immediately between an electrical device and a junction box terminal, such as wires 204 and connectors 208.

[0121] FIG. 25, wherein like reference numbers refer to like components from FIGS. 22-24, exemplary junction box 184D is schematically depicted. Junction box 184D includes a single exposed electrical connector 212′ having a plurality of pins 220. Some of the pins 220 are operatively connected to wires 216 in the conduit 188 so as to be connected to at least one other pin in at least one of the other junction boxes (not shown). Some of the pins 220 are operatively connected to other pins 220 within junction box 184D by wires 222. The single connector 212′ is engageable with complimentary connector 196 on harness 192D.

[0122] Vehicle manufacturers typically offer vehicles of a particular model with optional features. The optional features typically employ electrical devices; thus some vehicles of a particular model have a different combination of electrical devices than other vehicles of the same model. In other words, some vehicles of a particular model have a different quantity of electrical devices than other vehicles of the same model, or some vehicles have electrical devices that are differently-configured than the electrical devices of other vehicles of the same model in order to perform a different function or to perform the same function in a different manner.

[0123] Within the scope of the claimed invention, an electrical device is “differently-configured” from another electrical device if (1) it generates or consumes a different amount of electrical power than the other device under identical conditions; (2) it responds to control signals differently from how the other device responds to identical control signals under identical conditions; (3) it transmits control signals that are different from the control signals the other device transmits under identical conditions; (4) it has a different size or shape than the other electrical device; (5) it has a different electrical interface, i.e., connector; (6) it includes a different material composition; etc. The electrical distribution system can be employed to reduce complexity of vehicle assembly and provide flexibility in the assembly of vehicles having different options.

[0124] The electrical distribution system preferably contains sufficient conductive paths and sufficient terminals to accommodate, and operatively interconnect, the electrical devices of each of the electrical device combinations available for a particular vehicle model. The electrical distribution system is thus a standard, commonized system that can be used without modification in multiple vehicles each having a different quantity of electrical devices or differently-configured electrical devices from one another.

[0125] Referring to FIG. 26, wherein like reference numbers refer to like components from FIGS. 22-25, vehicle chassis 10g″ includes electrical distribution system 180, which is substantially identical to the electrical distribution system 180 of FIG. 22. Vehicle chassis 10g″ includes a selection and combination of electrical devices that have a different quantity of electrical devices than the selection and combination of electrical devices in vehicle chassis 10g of FIG. 22. The selection and combination of electrical devices of vehicle chassis 10g″ also have electrical devices that are differently-configured from every electrical device in the selection and combination of electrical devices in vehicle chassis 10g of FIG. 22. More specifically, vehicle chassis 10g″ does not include a cooling fan, a heating, ventilating and air conditioning system, or wheel motors. The fuel cell stack 125″ is larger in size and has a larger maximum electrical output than the fuel cell stack 125′ of FIG. 22. The electrical devices of chassis 10g″ are operatively connected to the electrical distribution system 180 such that each of the devices is in operative electrical communication with at least one other electrical device.

[0126] A chassis assembler may maintain an inventory of differently-configured small wiring harnesses to accommodate the connection of different electrical device selections and combinations to the electrical distribution system. For example, wiring harnesses 192A′, 192B′, 192C′ have a different quantity of individual electrical wires than similarly positioned harnesses 192A, 192B, 192C of FIG. 22. Pins in the junction boxes that correspond to an electrical device that is not part of chassis 10g″ are simply unused. Thus, connectors 196′ do not engage the same quantity of pins in the junction box electrical connectors as similarly positioned connectors 196 of FIG. 22.

[0127] Referring to FIG. 27, wherein like reference numbers refer to like components from FIGS. 22-26, vehicle chassis 10g′″ includes an electrical distribution system 180′ substantially identical to the electrical distribution system 180′ of FIG. 23. Vehicle chassis 10g′″ includes a selection and combination of electrical devices having a different quantity of electrical devices than the selection and combination of electrical devices in vehicle chassis 10g′. The selection and combination of electrical devices of vehicle chassis 10g′″ also have electrical devices that are differently-configured from every electrical device in the selection and combination of electrical devices in vehicle chassis 10g′ of FIG. 23. More specifically, vehicle chassis 10g′″ does not include a cooling fan, a heating, ventilating and air conditioning system, or wheel motors. The fuel cell stack 125″ is larger in size and has a larger maximum electrical output than the fuel cell stack 125′ of FIG. 23. A junction box electrical connector is simply unused in vehicle chassis 10g′″ if the electrical connector does not have a corresponding electrical device employed in vehicle chassis 10g′″.

[0128] FIG. 28, wherein like reference numbers refer to like components from FIGS. 22-27, schematically depicts an electrical distribution system 180″ installed in vehicle chassis 10h. Electrical distribution system 180″ comprises two junction boxes 184E, 184F operatively interconnected by one conduit 188 with wires (not shown). Vehicle chassis 10h includes two electrical connectors 91″ engageable with complementary electrical connectors on a vehicle body (not shown). Electrical connectors 91″ are integral parts of junction boxes 184E, 184F to further simplify the wiring of the vehicle chassis 10h. Two wiring harnesses, 192A′, 192B′ interconnect the electrical devices with a proximate junction box 184E, 184F.

[0129] Referring to FIG. 29, wherein like reference numbers refer to like components from FIGS. 22-28, fault detection and monitoring systems within the electrical distribution system 180″ are schematically depicted. Various wires, connectors, and other components of the electrical distribution system 180″ are not shown for clarity. An electrical device 226 is configured to transmit electrical energy in the form of an electrical signal 228 to junction box 184E via at least one terminal 230 in one of the electrical connectors of junction box 184E. The electrical signal 228 is transmitted by a conductive path from the at least one terminal 230 of junction box 184E through the conduit 188 to junction box 184F. An electrical device 232 is operatively connected to the conductive path via at least one terminal 230 in a connector of junction box 184F to receive the electrical signal 228 from the conductive path.

[0130] Various connectivity issues may arise in any electrical distribution system. For example, noise may diminish the quality of an electrical signal, or a problem in the electrical distribution system may result in a loss of signal strength. The electrical distribution system 180″ preferably includes sensors and microprocessors to monitor and detect fault conditions in the electrical distribution system 180″.

[0131] In order to detect problems with energy loss or signal strength, a sensor 234 is sufficiently configured and positioned with respect to the conductive path to measure a characteristic of the conductive path in junction box 184E and transmit a sensor signal 236 indicative of the value of the characteristic to a microprocessor 238 in junction box 184F. The measured characteristic is preferably voltage or current. A sensor 240 is sufficiently configured and positioned with respect to the conductive path to measure the characteristic of the conductive path in junction box 184F and transmit a signal 242 indicative of the value of the characteristic to microprocessor 238.

[0132] The microprocessor 238 is programmed and configured to compare signal 236 and signal 242, and to generate a signal 244 indicative of a fault condition if the value indicated by signal 242 differs more than a predetermined amount from the value indicated by signal 236. The signal 244 is transmitted to an interface 246 for the microprocessor, such as a pin in the electrical connector 91″, to alert a vehicle operator, technician, onboard diagnostics system, etc., of the fault condition.

[0133] In order to detect problems with the quality of signal transmission, a microprocessor 248 is sufficiently configured and positioned with respect to the conductive path to receive and replicate the signal 228 in junction box 184E transmitted by the electrical device 226 to generate a replicate signal 250. In the context of the present invention, a “replicate signal” is a signal that is a copy or reproduction of another signal. The microprocessor 248 is configured to transmit the replicate signal 250 to microprocessor 238 in junction box 184F. Microprocessor 238 is sufficiently configured and positioned to receive the signal 228 from the conductive path in junction box 184F.

[0134] Microprocessor 238 is programmed to compare the signal 228 as received in junction box 184F to the replicate signal 250, and to transmit a signal 244 indicative of a fault condition to the interface 246 if the signal 228 as received at junction box 184F differs from the replicate signal 250 more than a predetermined amount.

[0135] FIG. 30, wherein like reference numbers refer to like components from FIGS. 22-29, schematically depicts an inventory 254 of substantially identical electrical distribution systems 180. The electrical distribution systems of vehicle chassis 10g, 10g″ are preferably taken from the inventory 254. Alternatively, an inventory could contain a plurality of other electrical distribution system configurations, such as the electrical distribution system 180′ depicted in FIGS. 23 and 27, or the electrical distribution system 180″ depicted in FIG. 28.

[0136] FIG. 31 schematically depicts a method of advantageously employing electrical distribution systems to coordinate the electrical communication of vehicle electrical devices. The method comprises determining a quantity of electrical device combinations for a vehicle portion 258. Within the scope of the claimed invention, a “vehicle portion” may include an entire vehicle, or a lesser portion thereof, such as a chassis or body. The electrical device combinations differ quantitatively or functionally from one another. A combination differs quantitatively from another combination if the combination has a different quantity of electrical devices from the other combination. A combination differs functionally from another combination if the combination contains an electrical device that is differently-configured from every electrical device in the other combination. The method also comprises maintaining an inventory of substantially identical electrical distribution systems 262. The electrical distribution systems each have a plurality of junction boxes that include at least one electrical connector with terminals and a plurality of conductive paths connected to the plurality of junction boxes to operatively interconnect the terminals. The electrical distribution systems each include sufficient conductive paths and sufficient terminals to accommodate, and operatively interconnect, the electrical devices of each of the quantity of electrical device combinations without modification.

[0137] The method may also comprise assembling a first vehicle portion 266. The first vehicle portion has a first plurality of electrical devices according to one of the quantity of electrical device combinations, and a first electrical distribution system taken from the inventory. The first plurality of electrical devices is operatively connected to the first electrical distribution system so that the electrical distribution system operatively interconnects the first plurality of electrical devices. The method may also comprise assembling a second vehicle portion 270. The second vehicle portion has a second plurality of electrical devices according to one of the quantity of electrical device combinations different from the first plurality, and a second electrical distribution system taken from the inventory. The second plurality of electrical devices is operatively connected to the second electrical distribution system so that the electrical distribution system operatively interconnects the second plurality of electrical devices.

[0138] The first plurality of electrical devices preferably includes electrical devices that at least partially form a first by-wire steering system, a first by-wire braking system, and a first by-wire energy conversion system. The second plurality of electrical devices preferably includes electrical devices that at least partially form a second by-wire steering system, a second by-wire braking system, and a second by-wire energy conversion system.

[0139] FIG. 32 schematically depicts a method of advantageously employing electrical distribution systems to increase flexibility in vehicle assembly. The method comprises assembling a first vehicle portion 274. The first vehicle portion includes a first selection of electrical devices characterized by a first quantity of electrical devices. Each of the electrical devices of the first selection is characterized by a configuration.

[0140] A first electrical distribution system operatively interconnects the first selection of electrical devices. The first electrical distribution system has a first plurality of conductive paths, and a first plurality of junction boxes spaced a distance apart from one another. Each of the first plurality of junction boxes includes at least one electrical connector and is operatively connected to the first plurality of conductive paths so that the at least one electrical connector is an access port to at least one of the first plurality of conductive paths.

[0141] The first selection of electrical devices is sufficiently operatively connected to the first plurality of conductive paths so that each electrical device of the first selection is in electrical communication with at least one other electrical device of the first selection. Each of the first plurality of junction boxes operatively connects, via its respective at least one electrical connector, at least one of the electrical devices of the first selection to the first plurality of conductive paths.

[0142] The method may also comprise assembling a second vehicle portion 278. The second vehicle portion includes a second selection of electrical devices characterized by a second quantity of electrical devices. Each of the electrical devices of the second selection is characterized by a configuration.

[0143] A second electrical distribution system that is substantially identical to the first electrical distribution system operatively interconnects the second selection of electrical devices. The second electrical distribution system has a second plurality of conductive paths, and a second plurality of junction boxes spaced a distance apart from one another. Each of the second plurality of junction boxes includes at least one electrical connector and is operatively connected to the second plurality of conductive paths so that the at least one electrical connector is an access port to at least one of the second plurality of conductive paths.

[0144] The second selection of electrical devices is sufficiently operatively connected to the second plurality of conductive paths so that each of the electrical devices of the second selection is in electrical communication with at least one other of the electrical devices of the second selection. Each of the second plurality of junction boxes operatively connects, via its respective at least one electrical connector, at least one of the electrical devices of the second selection to the second plurality of conductive paths.

[0145] The second quantity of electrical devices is different from the first quantity of electrical devices, or the second selection includes an electrical device that is differently-configured from every electrical device of the first selection.

[0146] It may be advantageous for the first vehicle portion to include a first by-wire steering system, a first by-wire braking system, a first by-wire energy conversion system, and a first energy storage system operatively connected to the first by-wire energy conversion system. The first selection of electrical devices at least partially forms one of the first by-wire steering system, the first by-wire braking system, the first by wire energy conversion system, and the first energy storage system. Similarly, the second vehicle portion may include a second by-wire steering system, a second by-wire braking system, a second by-wire energy conversion system, and a second energy storage system operatively connected to the second by-wire energy conversion system. The second selection of electrical devices at least partially forms one of the second by-wire steering system, the second by-wire braking system, the second by wire energy conversion system, and the second energy storage system.

[0147] As set forth in the claims, various features shown and described in accordance with the different embodiments of the invention illustrated may be combined.

[0148] While the best modes for carrying out the invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the scope of the invention within the scope of the appended claims.