Internal combustion engine air supply device

Abstract: An internal combustion engine air supply device (1) comprising a body (7) having a channel (2) for supplying air to the engine; a throttle (3) installed along the channel (2); drive means (4) for operating the throttle (3); and a sensor (27) for detecting the position of the throttle (3). The main characteristic of the present invention consists in the fact that the device (1) comprises an electronic device (34) for controlling the drive means (4) and the sensor (27); and a seat (12) formed in the body (7) and housing the electronic device (34).

Description: The present invention relates to an internal combustion engine air supply device. As we know, internal combustion engine air supply devices substantially comprise a throttled body, a torque motor for operating the throttle, and a sensor for detecting the position of the throttle. Air supply devices of the aforementioned type present several drawbacks. In particular, the electronics controlling the electric components on the throttled body are installed in the electronic control system controlling the internal combustion engine and all the other electric components on the vehicle, so that the control system is both cumbersome and, hence, difficult to house. Moreover, by virtue of being housed inside the engine compartment on the vehicle, the electronic control system is also unfavourably located as regards effective heat exchange. As we know, the engine compartment is one of the hottest parts of the vehicle, and poses serious problems as regards heat exchange for dissipating the heat produced by the electronic blocks with which the control system is provided, and also by the power blocks of the electronics controlling the electric components on the throttled body. The control system and the electric components on the throttled body are connected electrically over cables necessarily extending over a long route. Extensive routing of the electric cables is known to result in electronic disturbance frequently caused by interference with the electromagnetic fields produced by nearby electric components, so that the electric cables act as an antenna for receiving spurious signals. Finally, in view of the length of the path along which the electric cables are routed, care must be taken to avoid thermal and mechanical hazards by which the cables might possibly be damaged; and a number of assembly brackets and anchoring devices are required, thus increasing the complexity and cost of the electric connections. The European Patent n. 405935A1 suggests a first solution for this problems. This solution proposes the use of an electronic device for controlling the actuator which operates the throttle. The electronic device comprises some printed circuits and a sensor which detects the position of the throttle. It is an object of the present invention to provide an internal combustion engine air supply device designed to enable a reduction in the size of the control system, a reduction in, and hence more effective dissipation of, the heat produced by the control system, and which provides for solving the problems posed by the electric connections between the control system and the components on the throttled body. Further objects and advantages of the present invention will be disclosed in the following description. According to the present invention, there is provided an internal combustion engine air supply device comprising a body having a channel for supplying air to said internal combustion engine; a throttle installed along said channel; drive means for operating said throttle; and a sensor for detecting the position of said throttle; an electronic device for controlling said drive means and said sensor, said electronic device including a printed circuit in turn comprising a number of electric blocks; and a first seat formed in said body and housing said electronic device; characterized by the fact that said electric blocks are defined by first low-heat-dissipation electric blocks and by second high-heat-dissipation blocks; said second blocks being located on a portion of said printed circuit close to said channel. A preferred embodiment of the present invention will be described by way of example with reference to the accompanying drawings, in which: Fig.1 shows a partially sectioned view of a device in accordance with the teachings of the present invention; Fig.2 shows a cross section of the Fig.1 device; Fig.3 shows a side view of the Fig.1 device. Number 1 in the accompanying drawings indicates an air supply device for a vehicle internal combustion engine (not shown). Device 1 comprises a substantially cylindrical channel 2 of axis 9, for supplying air to the internal combustion engine; a throttle 3 housed inside channel 2, for choking the air supply; a motor 4 (normally a torque motor) for operating throttle 3; a sensor 27 for detecting the position of throttle 3; and a printed circuit 6 comprising a number of electric blocks for controlling motor 4 and sensor 27, and for additional functions described hereinafter. Device 1 also comprises a metal body 7 in which are formed said channel 2; a seat 8 of axis 10, for housing motor 4; a seat 11 also of axis 10, for housing a spring assembly 26 and a limit stop 5 for assembly 26; and a seat 12 for printed circuit 6. As shown in the accompanying drawings, body 7 comprises a substantially prismatic central element 13 having a through hole of axis 9 and defining channel 2; a box element 14 originating from a first outer lateral wall 15 of element 13 and internally defining seat 8; and a box element 16 extending from a second outer lateral wall 17 of element 13, opposite said first wall 15, and internally defining seat 11. A tubular portion 19, defining the mouth of channel 2, extends outwards of element 13 from lateral wall 18 of element 13 and coaxially with channel 2. Between walls 15 and 17, element 13 presents a lateral wall 21 from which originates a coplanar tab 22; wall 21 and tab 22 defining the end wall of seat 12. Tab 22 extends from the edge defined between walls 21 and 17, and by a length greater than the longitudinal extension of element 16, so that (Fig.1) the first portion of tab 22 is an integral part of a corresponding lateral wall of element 16. As shown in Fig.2, seat 8 presents a fluidtight cover plate 23 screwed to element 14 by means of screws 24; and motor 4 presents an output shaft 25, of axis 10, extending from seat 8 to seat 11 and through channel 2. The portion of shaft 25 inside channel 2 is fitted by means of screws 29 with throttle 3; while the portion of shaft 25 inside seat 11 is fitted with sensor 27, which, in the example embodiment shown, is represented by an electric potentiometer. Between shaft 25 and an anchorage defined by a portion of element 16, seat 11 houses spring assembly 26 of known type and operation. Sensor 27 is integrated in the (fluidtight) cover plate of seat 11, and is screwed to element 16 by means of screws 28. With reference to Fig.s 1 and 3, seat 12 is defined by an end wall composed of wall 21 and tab 22; by four low lateral walls 31; and by a fluidtight cover plate 32. Printed circuit 6 is fitted to the end wall of seat 12 by means of screws 33, and presents a so-called "intelligent" electronic device 34 capable of processing data, controlling and diagnosing motor 4 and sensor 27, and transmitting and receiving data to/from an electronic control system 35 controlling the vehicle internal combustion engine, and to/from a control panel 36 in the passenger compartment of the vehicle. Control system 35 and panel 36 are shown schematically by respective blocks in Fig.1. Device 34 comprises a number of electronic blocks divided schematically into low-heat-dissipation blocks 34a producing little heat as a consequence of the Joule effect, and high-heat-dissipation power blocks 34b producing considerable heat as a consequence of the Joule effect, and including, for example, the driver of motor 4 and the electric supply stabilizer of device 34. Blocks 34b are located in a portion 38 of printed circuit 6 close to a lateral wall portion of channel 2 (as shown in Fig.1), so that the heat produced by blocks 34b is advantageously dissipated towards the air flowing along channel 2 and which thus also provides for cooling device 1. With reference to Fig.s 1 and 3, printed circuit 6 presents a group 41 of electric connections for connecting circuit 6 to the terminals of the electric winding of motor 4; a group 42 of electric connections for connecting circuit 6 to the terminals of sensor 27; and a group 43 of electric connections for connecting circuit 6 to a male connector 44 supported on tab 22. All the above electric connections are welded so that efficiency is unaffected by vibration of body 7. Male connector 44 is connected to a female connector 45 (Fig.1) from which originate two bundles 46 of electric cables respectively connecting control system 35 and panel 36. Bundles 46 are fitted with an antivibration clamp 51 screwed by means of screw 52 to the plate defined by sensor 27. As shown in Fig.1, the block indicating control system 35 contains a block 53 indicating a data storage circuit, in particular for memorizing the speed of the vehicle; and the block indicating panel 36 contains four blocks 47, 48, 49, 50 indicating the members for controlling or enabling the overall function of panel 36, which consists in automatically controlling the speed of the vehicle. In more detail, block 47 indicates a manually operated switch for enabling or disabling the automatic vehicle speed control function of panel 36. Block 48 indicates a manually operated switch for memorizing in block 53 and setting by means of control system 35 a vehicle speed equal to the traveling speed of the vehicle when block 48 is operated. Block 49 indicates a switch operated by means of the brake and/or clutch pedal for temporarily disabling the automatic control function of panel 36. Block 50 indicates a switch operated manually between two states for setting a vehicle speed selection strategy immediately following operation of block 49, normally as a result of braking. In a first of said two states, vehicle speed is controlled by the user via the accelerator pedal; while, in the second, the vehicle is restored automatically to the set memorized speed. Device 34 performs various functions, of which only the principal ones will be dealt with herein. These include enabling control of motor 4, and evaluating the response of throttle 3 to motor 4, as indicated by throttle position sensor 27. In this way, it is possible to determine any positioning errors of throttle 3 due to a defect on motor 4 or to severe friction along shaft 25. Device 34 also determines the energy consumption of motor 4, which, if excessive, indicates either a defect on motor 4 or severe friction along shaft 25. In other words, device 34 provides for locally diagnosing operation of motor 4 and sensor 27. Another principal function of device 34 consists in evaluating the consistency, i.e. the correct sequence, of the controls set by blocks 47, 48, 49 and 50, which obviously translates into a diagnosis of the blocks themselves. The advantages of the present invention will be clear from the foregoing description. Firstly, it provides a solution to the installation problems of electronic control system 35 inside the engine compartment, both as regards the size of the system, and the amount of heat produced and the manner in which it is dispersed. According to the present invention, in fact, control system 35 controlling the internal combustion engine and all the other electric components on the vehicle is smaller as compared with currently used systems, by virtue of the electronics controlling the electric components on throttled body 7 being separated from system 35. From the heating standpoint also, control system 35 produces less heat as compared with currently used systems; and, on device 1, the electronic blocks of device 34 producing most heat are concentrated in a limited area close to the lateral wall of channel 2, thus enabling the air flowing along channel 2 to be exploited for dissipating the heat produced by device 34. Such dissipation obviously also provides for advantages as regards the engine, especially when this is cold-started. Secondly, the length of the electric connections between the control blocks of the throttled body and the electric components on the body itself is minimized, thus minimizing electronic disturbance caused by interference with the electromagnetic fields produced by any nearby electric components. Thirdly, minimizing the length of the electric connections provides for troublefree routing of the cables inside the engine compartment; for eliminating the need to so route the cables as to avoid thermal and mechanical hazards by which the cables might be damaged; and also for considerably reducing assembly cost by eliminating the assembly brackets and anchorages. Moreover, the functions (control, check, diagnosis, etc.) performable directly on throttled body 7 by device 34 are unaffected by signal errors caused, for example, by electrical interference of any type, and as such are more precise and effective. Also, by virtue of being welded, the electric connections between device 34 and the electric components connected to it are unaffected by vibration of body 7, thus improving the efficiency and extending the working life of the connections.

Claims: Internal combustion engine air supply device comprising a body (7) having a channel (2) for supplying air to said internal combustion engine; a throttle (3) installed along said channel (2); drive means (4) for operating said throttle (3); and a sensor (27) for detecting the position of said throttle (3); an electronic device (34) for controlling said drive means (4) and said sensor (27), said electronic device including a printed circuit (6) in turn comprising a number of electric blocks (34a, 34b); and a first seat (12) formed in said body (7) and housing said electronic device (34); characterized by the fact that said electric blocks are defined by first low-heat-dissipation electric blocks (34a) and by second high-heat-dissipation blocks (34b); said second blocks (34b) being located on a portion (38) of said printed circuit (6) close to said channel (2). A device as claimed in Claim 1, characterized by the fact that said printed circuit (6) presents a first group (41) of electric connections for connecting said printed circuit (6) to the terminals of said drive means (4); a second group (42) of electric connections for connecting said printed circuit (6) to the terminals of said sensor (27); and a third group (43) of electric connections for connecting said printed circuit (6) to a male connector (44); said first, second and third groups (41, 42, 43) of electric connections being welded. A device as claimed in Claim 2, characterized by the fact that said male connector (44) is connected to a female connector (45) from which originates a first bundle (46) of electric cables for connection to an electronic control system (35) controlling said internal combustion engine. A device as claimed in Claim 3, characterized by the fact that, from said female connector (45), there originates a second bundle (46) of electric cables for connection to an automatic control panel (36). A device as claimed in at least one of the foregoing Claims, characterized by the fact that said first seat (12) presents a fluidtight cover plate (32). A device as claimed in at least one of the foregoing Claims, characterized by the fact that said body (7) comprises said channel 2; said first seat (12); a second seat (8) housing said drive means (4); and a third seat (11) housing said sensor (27). A device as claimed in Claim 6, characterized by the fact that said body (7) comprises a substantially prismatic central element (13) having a through hole defining said channel (2); a first box element (14) originating from a first outer lateral wall (15) of said central element (13) and internally defining said second seat (8); and a second box element (16) extending from a second outer lateral wall (17) of said central element (13), opposite said first wall (15), and internally defining said third seat (11); between said first and second lateral walls (15, 17), said central element (13) presenting a third lateral wall (21) from which originates a coplanar tab (22); said third wall (21) and said tab (22) defining the end wall of said first seat (12).

Inventors: AUSIELLO FRANCESCO PAOLO, CANNONE DOMENICO, AUSIELLO, FRANCESCO PAOLO, CANNONE, DOMENICO
Applicants: MAGNETI MARELLI SPA, MAGNETI MARELLI S.p.A.
Application year: 1993
Main classification: F02D11
IPC codes: F02D11