Abstract:
Central mounting of control electronics proximate to the engine is provided by attaching the electronics to an upper surface of the intake manifold to provide heat shielding and heat conduction for active components on the circuit card. The central location provides extremely short harnesses to important actuators located in cylinder heads of the engine thus reducing wiring clutter and cost.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to Provisional Appln. No. 60/130,860, filed Apr. 22, 1999. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     BACKGROUND OF THE INVENTION 
     The present invention relates generally to automotive electronics and in particular to a method of simplifying control wiring within the engine compartment by mounting control electronics on the air intake manifold. 
     Internal combustions used in automobiles and the like employ sophisticated engine control technologies making use of a variety of sensors and actuators and communication with microprocessor-based control circuitry. Generally engine control provided by these systems offers increased performance, reduced emissions and higher reliability in the operation of the vehicle. 
     Currently, the microprocessor-based control circuitry may be located near the vehicle firewall to provide a secure mounting of the circuitry away from the high temperature components of the engine and communicating with driver instrumentation in the passenger compartment. 
     The control circuitry communicates with a variety of sensors on or close to the engine including, for example, sensors for air mass flow, engine temperature, throttle position, engine speed and crankshaft position. The control circuitry in receiving these sensor signals, produces actuator signals to control throttle valves, fuel injectors, ignition coils, engine valves and the like. 
     The sensors and actuators must be connected to the control circuitry by wiring and the wiring must be of sufficient gauge to resist breaking under the tensile load and flexures incident to the normal service. The wires are therefore typically bound together in “harnesses” to improve their mechanical resilience and may be sheathed to better resist abrasion. 
     Wiring harnesses represent a significant cost in manufacturing of the vehicle, not only in cost of material and manufacture, but also in costs of routing and connection to the sensors and actuators. Mechanically robust harnesses add weight to the vehicle affecting vehicle mileage and emissions. The harness with its attendant branching wire sets can increase the clutter in the engine compartment adversely affecting the assembly, maintenance and repair of the engine. Further, long wire harnesses are a source of Electromagnetic Interference (EMI) which may adversely affect the performance of all vehicle electronics. 
     BRIEF SUMMARY OF THE INVENTION 
     The present inventors have recognized that a significant number of actuators are concentrated near the heads of the engine cylinders. Accordingly, placement of the control electronics at a central location between the engine cylinders can significantly reduce wiring. The sensitivity of the electronics to high temperatures normally occurring near the engine may be solved by a special circuit carrier supported by the intake manifold that may block the transmission of heat to the circuitry from the engine and may remove heat internally generated by such circuitry. 
     Specifically, the present invention provides an intake manifold circuit carrier including an air intake manifold providing chamber walls conducting air from a throttle body opening to a plurality of exit ports associated with locations of cylinders on an internal combustion engine. Support walls are provided extending outwardly from the chamber walls to define a volume adjacent to the chamber walls. The circuit board having circuit components mounted thereon and including a first aperture is attached to a heat conductive plate on the first side of the circuit board, the heat conductive plate being in thermal communication with it to form a laminated plate assembly. The heat conductive plate has a second aperture aligned with the first aperture in the circuit board and the laminated plate assembly is attached to an upper edge of the support walls to cover the volume with the circuit board internal to the heat conductive plate with respect to the volume. 
     Thus, it is one object of the invention to create a hospitable environment for temperature sensitive electronic components near the actuators associated with engine cylinders. 
     A throttle body may be included having a central lumen and attached to the laminated plate assembly with the lumen aligned with the first and second apertures so as to place the throttle body in thermal communication with the heat conductive plate. The throttle body may include fins projected inward to the lumen to conduct heat from the throttle body to air passing across the fins. 
     Thus it is another object of the invention to provide a path of heat conduction away from the electronics into the air normally aspirated by the engine. 
     The support walls may be molded of heat conductive plastic or may be an integral part of the intake manifold. 
     Thus it is another object of the invention to provide a path of heat conduction into the air normally drawn through the chamber walls of the intake manifold. 
     The short harnesses required between the circuit card and the actuators on the cylinder heads may be conventional wire harnesses terminating in electrical connectors that may connect to the actuators or may be extensions of a flexible circuit board substrate of the circuit board terminating in electrical connectors or may be a conductor assembly (for example, a rigid plastic) having electrical connectors attached to corresponding connectors on the printed circuit board and also attached to the control component or may be conductors attached directly to the air intake manifold. 
     Thus it is another object of the invention to provide great flexibility in the construction of the harnesses based on their short length and close proximity to the control actuators. 
     In an alternative embodiment of the invention, the intake manifold circuit carrier may include an air intake manifold providing chamber walls conducting air from an entrance port to a plurality of exit ports associated with locations of the cylinders on an internal combustion engine. Support walls may extend outward from the chamber walls to define a volume adjacent to the chamber walls. A circuit board having circuit components mounted thereon may be sandwiched between the upper edge of the support walls and a cover shroud attachable at the upper edge of the support walls, the cover shroud when so assembled, providing air channels conducting air from a throttle body port in the cover shroud pass the circuit board leading to the entrance port of the air intake manifold. 
     Thus it is another object of the invention to provide direct airflow of aspirated engine air across the circuit board to provide cooling thereof. 
     The foregoing and other objects and advantages of the invention will appear from the following description. In this description, reference is made to the accompanying drawings, which form a part hereof, and in which there is shown by way of illustration, a preferred embodiment of the invention. Such embodiment and its particular objects and advantages do not define the scope of the invention, however, and reference must be made therefore to the claims for interpreting the scope of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a simplified perspective view of an engine showing location of the engine cylinders in phantom and the position of the air intake manifold beneath the circuit carrier of one embodiment of the present invention; 
     FIG. 2 is a cross-section taken along lines  2 — 2  of FIG. 1 of a circuit card used in the carrier of the present invention as constructed of a flexible substrate having extensions forming harnesses and as attached to a heat conductive plate; 
     FIG. 3 is a view similar to that of FIG. 2 showing the attaching of side walls and a gasket material to the circuit card and a coating applied to the exposed portions of the harness extensions; 
     FIG. 4 is a figure similar to that of FIG. 2 showing the circuit card inverted and placed on inner and outer support walls of the circuit carrier of the present invention attached to the manifold of FIG.  1  and to a throttle body and showing paths of heat conduction from the components on the circuit card 
     FIG. 5 is an axial cross-sectional view of the throttle body of FIG. 4 showing radially inward extending fins; 
     FIG. 6 is a fragmentary view similar to that of FIG. 4 showing a second embodiment in which the inner support walls are removed and the walls of a throttle body provide direct heat conduction to aspirated air and wherein the throttle body is integrated with heat conductive plate. 
     FIG. 7 is a figure similar to that of FIG. 6 showing a third embodiment wherein the support walls are integral extensions of the air intake manifold; 
     FIG. 8 is a view similar to that of FIGS.  4  and  6 - 7  of a fourth embodiment in which the circuit card extensions are eliminated in favor of connectors connecting through the support walls to the intake manifold carrying conductors therein or on its surface; 
     FIG. 9 is a figure similar to FIGS.  4  and  6 - 8  showing yet an alternative embodiment in which circuit card based connectors attached to upwardly connectable connectors being part of the actuators controlled by the control electronics; 
     FIG. 10 is an alternative embodiment of the embodiment of FIG. 9 showing the use of downwardly extending conductors on the actuated components; 
     FIG. 11 is a view similar to FIGS.  4  and  6 - 11  showing an additional alternative embodiment in which a cover shroud is used to conduct aspirated air destined for the intake manifold across the circuit card and having extending portions for holding connections against vibration and including holes for passing air through the circuit card; 
     FIG. 12 is an alternative embodiment of the extended portions of FIG. 11 for use with a wire harness such as may also be used with other embodiments; 
     FIG. 13 is a plan view of the circuit card of FIG. 6 showing formation of harnesses through extensions of a flexible printed circuit board media; 
     FIG. 14 is an alternative embodiment of the circuit card such as may be used in the embodiment of FIGS. 10 and 11 showing wire harness extensions; 
     FIG. 15 shows an alternative embodiment to that of FIG. 13 in which a manifold formation of extensions is replaced with L-shaped arms; and 
     FIG. 16 is yet an alternative embodiment of the circuit card of FIG. 13 in which the arms arc not separated from one another. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to FIG. 1, an engine  10  suitable for use with the present invention provides an engine block  12  having a plurality of cylinders  14  at whose heads may be various actuators  16 . Currently, such actuators  16  include fuel injectors and ignition coils but in the future it is expected that such actuators  16  may also include engine valves and possibly sensing electronics. 
     An air-intake manifold  18  leads generally from an inlet  20  to conduct air within chamber walls  22  to exit ports  24  at the heads of the cylinders  14  according to methods well known in the art. 
     In the present invention, a circuit carrier  25  may be positioned centrally about the inlet  20  approximately centered between the cylinders  14 . While as depicted, the engine  10  is in a V-configuration with the circuit carrier  25  substantially at the center of the cylinders  14 , it will be understood from the following description that the invention may also be used for in-line engine configurations with the circuit carrier  25  positioned to the side of the cylinders  14  on the intake manifold. 
     Referring now to FIGS. 2 and 13, a circuit board  26  holding engine control electronics may include mounted on its surface, active components  28  and passive components  30  distinguished principally by their sensitivity to high temperature and their generation of internal heat. The active components  28  need generally a lower ambient temperature than the passive components  30 . The active components  28  are centrally mounted on the circuit board  26  while the passive component  30  may be mounted on harness portions  32  shown more clearly in FIG.  13 . 
     As will be described below, the harness portions  32  provide harness-like structures allowing connection of active components  28  and  30 , as connected by conductive traces  34  of the circuit board  26 , to the actuators  16  in the function of wiring harnesses. The harness portions  32  may be cut out of a single flexible substrate of the circuit board  26  or cut from separate flexible circuit board substrate and attached at a subsequent manufacturing step by soldering, welding or other methods known in the art. 
     The conductive traces  34  connects components  30  and  28  also to connectors  36  at the ends of the harness portions  32  such as may be received by other connectors on actuators  16  (shown in FIG. 4, for example). A central aperture  38  may be cut in the circuit board  26  as will align with the throttle body  66  as described below as well as mounting apertures  40  whose use will also be described. 
     Referring specifically to FIG. 2, a thermally conductive plate  42 , for example of an aluminum or magnesium material, may be attached to the rear side of the circuit board  26  opposite the components  28  and  30  to be electrically insulated from the conductive traces  34  (except perhaps for a ground connection) but thermally communicating with the active components  28 . The thermally conductive plate  42  may be glued to the rear side of the circuit board  26  with thermally conductive glues such as are known in the art. The conductive plate  42  may have an aperture  38 ′ and  40 ′ commensurate with apertures  38  and  40  and aligned with them when the conductive plate  42  is attached to the circuit board  26 . 
     Referring now to FIG. 3, a support frame  44  may be injection molded about the combined conductive plate  42  and circuit board  26  through in-molding techniques well known in the art in which molded rivets  46  pass through the combined apertures  40  and  40 ′ so as to retain the conductive plate  42  against the circuit board  26  and to hold the support frame  44  thereto. In a preferred embodiment, the support frame  44  is molded of a thermally and electrically conductive plastic, provided by the inclusion of metal particles in a thermal plastic binder, to provide heat conduction and shielding from electromagnetic interference. 
     The support frame  44  provides an upwardly extending outer wall  48  defining the periphery of the active components  28  and the conductive plate  42  and upwardly extending inner walls  50  ringing the apertures  38  and  38 ′, the two joined by one or more ribs  51 . 
     An elastomeric seal  54  may be molded on the top of the walls  48  and the harness portions  32  may be covered with an elastomeric protecting material  56 , of types well known in the art, to protect them against abrasion and short-circuiting of their surface conductors. 
     Referring now to FIG. 4, the air intake manifold  18  generally provides in the upper chamber wall  22  an entrance aperture  61  for conducting engine intake air  62  as shown by like numbered arrows to exit ports  64  associated with each cylinder  14  shown in FIG.  1 . Engine actuator component  16  may be mounted to the air intake manifold  18  or merely affixed relative to the exit ports  64 . 
     The assembly of FIG. 3 may be inverted and placed against the air-intake manifold with the upper edges of the walls  48  and  50  (per the orientation of FIG. 3) abutting upper chamber walls  22  of an air intake manifold  18 . In this configuration, the seals  54  arc compressed against the upper chamber wall  22  so that the walls  48  and  50  in touching the upper chamber wall  22  define an enclosed volume  60  in which the active components  28  are held. 
     As shown in FIG. 4, the interposition of the air-intake manifold  18  between the remainder of the engine  10  and the circuit board  26  allows flowing air  62  to collect heat  67  generated by the active components  28  themselves. 
     The throttle body  66 , conducting aspirated air  68 , may provide additional cooling to the volume  60  by conduction through throttle body walls  58  as augmented by internal fins  70  in the throttle body  66  in a portion passing between walls  50 . Referring to FIG. 5, the fins  70  may extend radially inward within the central lumen of the throttle body  66 . The fins are designed to provide minimal airflow restriction through the assembly. The throttle body  66  may rest against the conductive plate  42  to provide good thermal communication between that plate and the air  68  flowing through the throttle body  66 . When the engine is not running, additional heat flow paths  72  may occur through the conductive plate  42  from the volume  60  to ambient air. 
     Referring to FIGS. 4 and 13, the flexible harness portions  32  allow connectors  36  to be connected directly to the actuators  16  resulting in very short effective harnesses. 
     Referring now to FIG. 6, in an alternative embodiment, the throttle body  66  may be an integral part of the conductive plate  42  thus simplifying construction and improving heat flow between the two. Further, the inner wall  50  may be omitted allowing direct connection of the volume  60  to the throttle body wall  58 . These two variations may be used individually as will be understood from this description. 
     Referring now to FIG. 7, in another alternative embodiment, the walls  48  and  50  may be extensions from the air-intake manifold  18 , for example, cast as part of the metal casting of the air-intake manifold  18  or molded as part of a plastic molding of the air-intake manifold  18 . In this case, the thermal conductivity of the walls  48  and  50  to the air-intake manifold  18  may be improved. An elastomeric material  75  may be placed on the circuit board  26  so as to provide good sealing between walls  48  and  50  and the circuit board  26 . 
     The portion of the throttle body  66  passing between the walls  50  may be eliminated or per the embodiments of FIGS. 4 and 6 include a finned portion that passes through apertures  38  to be assembled in a sleeve-like configuration with walls  50  may be cut down to dotted line  76 . 
     In previous embodiments, the harness portions  32  were formed by flexible extensions of the circuit board  26 . In an alternative embodiment of FIG. 8, the circuit board  26 , which may be either on a flexible or rigid substrate, terminates at the edge of the conductive plate  42 . A connector  36 ′ may be attached directly to the circuit board  26  either as a separate component soldered to the circuit board  26  or by making use of the traces of the circuit board as connector elements as held in a molded shell. In either case, wall  48  then incorporates a mating connector half  82  communicating with conductors  78  embedded in or on the air-intake manifold  18  itself. In this way, assembly of the circuit board  26 , conductive plate  42 , and throttle body  66  to the air-intake manifold  18  also provides electrical connections to the actuators  16 . 
     The conductor  78  may be in-molded to a high temperature plastic material or may be attached to the surface of a metal casting or the like using adhesives or other techniques. A second connector  83  may be incorporated into the actuators  16  to receive the conductor  78  emerging from the air-intake manifold  18  as connector  36 ′. This allows attachment of the actuators  16  to the air-intake manifold  18  to provide for their electrical connection as well. In this case, the air-intake manifold  18  provides support structure for the conductor  78  avoiding the need for other structural components. 
     Referring now to FIG. 9, in a variation on the embodiment of FIG. 8, the downwardly extending connectors  36 ′ may be received by conductor support structure  80  being a rigid thermoplastic support formed as part of the actuators  16  or attached thereto and providing a path for conductor  78  and support of connector half  82 . Connector half  82  is positioned to join with the connector  36 ′ when the circuit board  26  is assembled to the air-intake manifold  18 . In this way, the air-intake manifold  18  need not be modified or in the case of failure of the internal conductor  78 , need not be replaced. 
     Referring now to FIG. 10, a similar arrangement may be provided with a connector  36 ″ extending upward from circuit board  26  past conductive plate  42  to connect with downward connector half  82 ′ attached to rigid support structure  80 ′ (similar to structure  80  but holding connector half  82 ′) to attach to connector  36 ″ after the circuit board  26  is assembled to the intake manifold  18 . Again the support structure  80 ′ includes an internal conductor  78  communicating with actuators  16 . In this case, the structure  80 ′ may serve to retain circuit board  26  in its position after it has been so assembled and may be an integral part of the actuator  16  eliminating the need for a second connector pair. 
     Referring now to FIG. 11, in a further embodiment, throttle body  66  may be attached to a shroud cover  87  having a generally planar plate  84  extending parallel to the circuit board  26 . The plate  84  is in substantially the same alignment as the conductive plate  42  described above but spaced from the circuit board  26  by downwardly extending bosses  86  and a peripheral wall  88  defining a chamber  90  between an upper surface of the board  26  and a lower surface of the plate  84 . This chamber  90  allows free circulation of aspirated air  68  along the upper surface of the circuit board  26 . 
     The central aperture  38  of the circuit board  26  need not be present in this case but instead vent slots  92  as shown in FIGS. 13 or  14  may be used to allow passage of air  68  past the circuit board  26  to an entrance aperture  61  of the air-intake manifold  18  (shown in FIG.  11 ). Outer walls  48  may still support the circuit board  26  above the chamber walls  22  of the intake manifold. However, inner walls  50  are replaced by upstanding bosses  93  that allow free passage of air  68  about the lower surface of the circuit board  26  within the walls  48  within volume  60 ′. In this way, direct air-cooling of the active components  28  may be accomplished. 
     Shroud wings  96  may extend from the plate  84  to cover the harness portions  32  and may have a foot portion  98  pressing on connector  36  to hold it engaged with connector  83  of actuators  16 . Thus shroud wing  96  provides not only a protective covering for the harness portions  32  but also a retention of the connectors  36 . 
     Referring now to FIG. 12, a similar shroud wing  96 ′ may be used when the harness portions  32  are discrete wiring as opposed to portions of the circuit board  26 . 
     Referring now to FIG. 14, construction of the circuit board  26  for the embodiment of FIG. 12 is shown with various wire harness portions  32 ′ connected to connectors  36 . 
     FIG. 15 shows an alternative embodiment to the embodiment of FIG. 14 in which a single rectangular and planar sheet of flexible material is used to form circuit board  26  and harness portions  32  with connectors  36  aligned along its lateral edges. 
     In FIG. 16 yet an alternative embodiment of the circuit board  26  is shown in which the harness portions  32  are formed as L-shaped members  100  formed of two segments attached at right angles, attached to a main body  102  of the circuit  26  at an end of one of the segments, this approach conserving on flexible substrate material. 
     It is specifically intended that the present invention not be limited to the embodiments and illustrations contained herein, but modified forms of those embodiments including portions of the embodiments and combinations of elements of different embodiments as come within the scope of the following claims.