FR2965927A1 - INSTALLATION FOR DETECTING THE ROTATION SPEED OF AN EXHAUST GAS TURBOCHARGER OF AN INTERNAL COMBUSRION ENGINE - Google Patents

Abstract

Apparatus for detecting the rotational speed (14) of a supercharging plant (10), in particular an internal combustion engine, and in particular an exhaust gas turbocharger. The supercharging system (10) comprises a housing (12) and a rotational speed detection system (14) equipped with a sensor (22). A cooling member (26) is associated with the sensor (22). This cooling member (26) is made of metal.

Description

FIELD OF THE INVENTION The present invention relates to an installation for detecting the speed of rotation of a supercharging installation, in particular of an exhaust gas turbocharger of an internal combustion engine, this supercharging installation. having a housing. STATE OF THE ART Rotational speed detection installations such as, for example, rotational speed detecting devices serve to detect the rotational speed of the supercharging installation such as, for example, the turbocharger equipping a vehicle with a speed of rotation. internal combustion engine. The design of the rotational speed detectors uses different measuring principles and is installed in different places. Usually, a rotational speed detecting device is used in the form of a rotational speed sensor in a supercharger such as a turbo-compressor by mounting this sensor on the compressor side of the turbo. exhaust gas compressor because the temperatures that are established are in a range below 220 ° C. In other words, these temperatures are much lower than those encountered on the turbine side of a turbocharger supercharger because then temperatures above 400 ° C can be achieved. Applications of the rotational speed detection system are known as rotational speed sensors using the principle of eddy currents. In such assemblies, the detection element is for example housed in a measurement sensor while the operating electronics is located at a remote location, connected by a cable connection to the measurement sensor due to the high temperatures. above 160 ° C; at the location of the operating electronics, the temperature level will be lower. According to other rotational speed sensor embodiments, magnets are installed on the front surface of the compressor shaft of the turbocharger-type supercharging system. A sensor detects the speed of rotation of the

2 mants using a GMR (giant magnetoresistance effect) element or using an eddy current sensor. The sensor is located in the upstream zone of the compressor and thus disrupts the aerodynamics of the turbocharger supercharger because the congestion resulting from the mounting of the sensor limits the maximum section available for the passage of the engine. 'air. It has been found that the high temperatures on the compressor side of the exhaust turbocharger housing only occur very briefly, only for a few minutes, especially after the vehicle has stopped, since then there is no longer a problem. circulation wind that ensures cooling. The high temperatures, however, related to the thermal conductivity of the housing of the supercharging plant remain. As soon as the internal combustion engine equipped with the supercharging system is started again, the fresh supply air passage through the compressor part ensures rapid cooling and thus a sudden drop in pressure. temperature level. Electronic components such as ASIC circuits and turntables used for speed sensors installed in the engine enclosure of a vehicle are designed for ambient temperatures up to 165 ° C. vs. In continuous operation of these ASIC circuits or the plates that carry them, the maximum permissible temperatures are only 155 ° C. Special ASIC enclosures, resistant to high temperatures, can only be used under very limited conditions because of their high cost. Document DE 10 2007 005796 A1 relates to a rotational speed detection installation associated with a supercharging installation, in particular to the rotor of the compressor part of an exhaust gas turbocharger. The exhaust gas turbocharger includes a housing having associated therewith a sensor circuit and at least one permanent magnet and at least one magneto-resistance element for detecting an alternating magnetic field. The housing is made of plastic and a wall of the housing includes

3 minus one permanent magnet, this permanent magnet and the sensor circuit being separated from each other. DESCRIPTION AND ADVANTAGES OF THE INVENTION The subject of the present invention is a rotational speed detection device of the type defined above, characterized in that it comprises a sensor element to which is associated a metal cooling member. . Thus, according to the solution of the invention, there is a cooling member made in particular of a metal and installed under the screw fixing flange at the sensor body of a rotational speed detection installation carried out under the as a sensor of the rotation speed and / or alternatively at the sensor head of the rotational speed detection device in the form of a rotational speed sensor. Thus, the cooling member according to the invention, which is made of a metal material, can reach the ni-calf of the eyelet for screwing the flange. This means that the flange is thermally coupled in a particularly good manner to the metal cooling member. The sensor element can use for example the GMR effect (giant magnetoresistant effect) to detect a light compressor that passes in front of the sensor. Alternatively, it is also possible to use an induction method such as, for example, a method using eddy currents. The cooling member is for example made in simple sheet by a shaping process such as for example creep pressing or deep drawing. In particular, the cooling member manufactured by cold forming can be put into its final form by simple folding or bending processes and once in its final form, it is mounted on the sensor element of the data acquisition system of the speed of rotation realized as a speed sensor. In particular, it is advantageous to make the metal cooling member and to give it, for example, a gooseneck shape to have an air gap for the sensor, at the bottom of the cup surrounding the sensor of the installation. rotational speed sensor in the form of a rotation sensor.

Alternatively, the cooling member can be made in the form of an extruded profile to the press. In the case of such a profile, it is possible to house the sensor or the sensor body in the cylindrical cavity of the extruded profile to the press and to use the cooling fins which project radially from the surface. envelope side to evacuate the heat. The cooling element which surrounds the sensor element of the rotational speed detection installation and which is made in particular of metal, also makes it possible to block the troublesome electromagnetic radiation which would arrive on the sensor, thanks to an effect screen. The rotational speed detection device according to the invention offers more freedom, thanks to the selection of appropriate sensors in principle, implemented in the speed detection installation. In addition to the use of a conventional CMOS-ASIC technique, the signals can be captured by the rotational speed detection device according to the invention using, for example, the GMR effect or the eddy current principle. (induction). In addition, the solution according to the invention makes it possible to greatly reduce the cost of the rotational speed detection installations which results in a non-negligible way from the fact that an ASIC circuit can be installed closer to a sensor itself, exposed to high level temperatures. In addition, the risk of mass production is reduced by the fact that known manufacturing techniques are used which have been confirmed for the sensor principles used until now. Finally, we will have a very compact form of construction for the installation of input of the rotational speed and have a small footprint. The quality of the signal is improved by avoiding long transmission lines between the sensor element and the operation of the signal, for example in the case of the inductive principle between the coil and the ASIC. The cooling member develops a screen effect that results in protection against electromagnetic waves (EMV) of the electrical circuits.

Drawings The present invention will be described in more detail below with the aid of various exemplary embodiments of a rotational speed detection installation, represented diagrammatically in the accompanying drawings in which: FIG. the mounting of a rotational speed detection device on the casing of a supercharging installation, in particular of an exhaust gas turbocharger, - FIG. 2 shows a first variant of the cooling member according to FIG. invention, made in the form of a cup, - Figure 2.1 shows the mounting of the sensor on the housing of the supercharging system, - Figure 2.2 shows the mounting of the sensor in a cavity of the housing of the installation of FIG. 3 shows another variant of the cooling element according to the invention, the fins of which surround the body of the fan-shaped sensor, FIG. section of the sensor according to section line III.1 - III.1 of FIG. 3; FIG. 4 shows a variant of the cooling element according to the invention in the form of an extrusion profile with radial fins extending in the radial direction of the envelope surface of the extruded profile, - Figure 4.1 is a section of the extruded profile constituting the cooling member, along the section line IV.1 - IV.1 of Figure 4, FIG. 5 shows another variant of the rotational speed detection device according to the invention, the cooling element of which is in the form of a cup, and whose point of reading of the sensor is in the housing. of a supercharging installation, - Figure 6 shows an alternative embodiment of the cooling member according to the invention which is partially overmolded by injection in the speed of rotation detection system and which surrounds both parts of the mounting flange and the onnecteur. 5 35

DESCRIPTION OF EMBODIMENTS OF THE INVENTION FIG. 1 shows the basic mounting of a sensor for detecting the rotational speed of a supercharging plant, in particular an exhaust gas turbocharger.

Thanks to the lower temperatures, the speed of rotation of the supercharging system 10 will be captured especially at the fins 11 of the compressor rotor because the temperatures are lower compared to the temperature level of the turbine rotor of the installation of overeating. The rotational speed acquisition system 14 is fixed to the housing 12 of the supercharging system 10. FIG. 1 shows that the speed sensor 14, that is to say the sensor, the rotational speed is surrounded by a cooling member 26, for example in the form of a cup 24. The rotation speed acquisition device 14 comprises a connection output 20 through which the speed sensor input installation rotation 14 is fixed for example by means of a fastener 32 in the form of a screw to a flange 16 of the sensor. The screw, that is to say the fixing element 32, connects the sensor flange 16 to a fastening means 18 itself mounted on a fastener 14 of the casing 12 of the supercharger; this fixing element 14 is preferably made with a high thermal resistance. The reference 17 denotes the axis of rotation of the rotor of the compressor carrying the fin 11. Variations of embodiment Figure 2 shows a first alternative embodiment of the cooling member according to the invention. In this variant, the cooling member surrounds the body of the sensor or of the sensor element of the speed-measurement acquisition system produced in the form of a speed-of-rotation sensor. The cooling member has a cup shape surrounding the body of the sensor.

According to FIG. 2, in a first variant of the cooling member according to the invention which is preferably made of metal, this member is applied to a supercharging installation 10, in particular in the form of a gas turbocharger. exhaust. This cooling member 26 has the shape of a cup 24.

In the first variant embodiment of FIG. 2 of the solution of the invention, which is a very simple embodiment, the rotational speed detection device 14 comprises a sensor body 21 substantially surrounded by the sensor member. This embodiment is particularly suitable, for example, for using ASIC circuits which detect the signals by magneto-resistance effect. The cooling member 26 (here in the form of a cup 24) is integrally connected mechanically and thermally to a fastening means 18 made of metal. Between the metal cup 24 and the sensor element 22, preferably plastic, housed in the sensor body 21, there preferably is an isolation air gap 28 around the sensor element 22 and the cooling member 26 formed here in the form of a cup 24 for thermal decoupling and insulation. The cooling member 26 is applied flat against the housing 12 of the supercharging system 10; in a variant, the cooling member 26 is housed in a blind hole-shaped opening of the housing 12 of the supercharging system 10.

According to FIG. 2, above the fixing means 18, which is preferably made of a metal having good thermal conductivity characteristics, there is a sensor head 23 traversed by an electrical line 20. In the variant embodiment of FIG. Figure 2, this power line has an angled trace to the connection output. The sensor head 23 of the rotational speed acquisition system 14 in the form of a rotational speed sensor is integrally connected via a sensor flange 16 with the aid of FIG. a fixing element 32, for example in the form of a screw, to the fixing means 18; this fixing means is preferably made of metal so as to have a contact promoting the thermal conductivity. According to FIG. 2, the heat emitted by the supercharging system 10, produced especially in the form of an exhaust gas turbocharger, is discharged from the sensor element 22 or its body 21 by the cooling member 25 in the form of a cup 24 because the cooling member 26 in the form of a

8 cup 24 is connected to the fastening means 18 by a heat conduction bond. There is also heat dissipation through the sensor head 23 and the power line 20 or the fastening flange 16 and the fastening means 18, preferably made of metal. Due to the particularly good thermal connection between the sensor element 22 and the electrical line 20, the electrical contact made in the speed-detecting installation 14 is preferably made using a metallic electrical rail. , continued. According to FIG. 2, the body 21 of the sensor of the rotation speed acquisition system 14 comprises a magnet 34 which is necessary if the sensor element 22 is produced for example in the form of a GMR effect sensor (effect giant magneto-resistant). Figure 2 shows that at the bottom 25 of the cup and at the periphery of the body 21 of the sensor, there is the isolation air gap 28 for performing thermal insulation. The cup-shaped cooling member 26 is preferably connected via the fastening element 32 which connects the sensor flange 16 to the fastening plate 33 on the motor side, thereby to be clamped and locked. . Figure 2.1 shows a detail of Figure 2.

According to FIG. 2.1, the installation for capturing the rotational speed 14 can comprise, in particular at the level of the lower face or of the lateral peripheral surface of the sensor body 21, spacing members 30 which guarantee the air gap. insulation 28 in relation to the inner side of the cooling member 26 in the form of a cup 24. In addition, the lower face of the speed-detecting device 14 also comprises spacers 30 below the The embodiment of Figure 2.1, the bottom 25 of the cooling member 26 in the form of cup 24 is applied against the outer face of the housing 12. of the supercharging plant. Figure 2.2 shows another alternative embodiment of the mounting of the cup-shaped cooling member on the housing of the supercharging system. According to FIG. 2.2, which corresponds to another variant embodiment, the bottom 25 of the cooling member 26 in the form of

9 cup 24 is housed in a cavity formed in the outer side of the housing 12 of the supercharging system 10. In this variant shown in Figure 2.2, there are also spacers 30 in the form of bosses, particularly at the level the lower face of the body 21 of the speed of rotation capture installation 14 and also at the peripheral surface; these spacers define the insulating air gap 28 both at the bottom of the cup and in the area of the side wall of the cup. Figure 3 shows another alternative embodiment of the cooling member according to the invention. According to FIG. 3, the supercharging installation 10 made in the form of an exhaust gas turbo-compressor comprises a housing 12 housing the fins 11 of the compressor rotor. The supercharging system 10 in the form of an exhaust gas turbocharger comprises the housing 12, a part of the wall of which appears in FIG. 3 with hatching. An attachment plate 33 which corresponds to the fixing means 18 of FIG. 2, made of metal, carries the installation for detecting the speed of rotation 14 fixed by means of a screw 32. The installation comprises in addition to the sensor head 23, the sensor body 21 and a sensor element 22 at its front face. The installation for capturing the speed of rotation 14 is preferably made of plastic. The speed detection device 14 is connected to the fixing plate 33 via the sensor flange 16 shown in FIG. 3.

According to FIG. 3, the body 21 of the sensor of the rotational speed detection installation 14 is surrounded by the cooling member 26. The cooling member 26, according to this alternative embodiment represented in FIG. Figure 3, has separate cooling fins 35 projecting from the sensor body 21 in the radial direction. As follows from FIG. 3, the different cooling fins 35 radially around the envelope surface of the sensor body 21 may have a different radial extension depending on the axial length of the sensor body 21. Thus, the cooling fins 35 of the cooling member 26 shown in FIG. 3 have a larger radial dimension at

10 of their side remote from the housing 12, compared to the radial extension of the cooling fins 35 at the front face of the sensor body 21 at the sensor element 22 on the side facing the housing 12 of the the supercharging system 10.

Figure 3.1 is a section of the cooling member of Figure 3 along the section line III.1 - 111.1. According to FIG. 3.1, the sensor body 21 of the speed-detection device 14, in particular the speed-of-rotation sensor, is on the one hand surrounded by the cooling fins 35 of the cooling member 26 and on the other hand, there is an insulation by air 36 distributed in a substantially star pattern; the insulation extends over different areas of the peripheral surface of the sensor body 21. The sectional view of Fig. 3.1 also shows that the different cooling fins 35 of the cooling member 26 have a different length in their direction. axial. Figure 4 shows another alternative embodiment of the cooling member according to the invention associated with the sensor element of the speed sensor. According to FIG. 4, the sensor element or, more simply, the sensor 22 and in particular its body 21 extends in the axial direction in the cavity of a press-extruded section 44. An annular air gap 28 exists between the envelope surface of the body 21 of the sensor 22 and the inner envelope surface of the press extrusion 44.

According to Figure 4, a number of cooling fins 46 are derived from the envelope surface of the press extrusion section 44. The cooling fins 46 can be distributed continuously or discontinuously, perpendicular to the plane of the sin, at the periphery of the profile 44. In place of a 45 ° distribution like that shown in FIG. 4.1, cooling ribs 46 extending in the radial direction of the extruded profile 44 to the press, it is also possible to have a larger or smaller number of cooling fins 46 at the envelope surface of the press extrusion 44.

According to FIG. 4, the cooling fins 46 extend substantially in the radial direction with respect to the shell surface of the pressed extrusion section 44, to enlarge the surface of the profile 44 to remove the heat. thermal conduction to the environment. Thus the body of the sensor 21, that is to say the sensor 22 of the speed of rotation capture installation 14 in the cavity of the pressed extrusion section 44, is protected against heat. Figure 5 shows another alternative embodiment of the solution of the invention. According to Figure 5, the cooling member 26 also has a cup shape but with an opening in the bottom. This opening can receive, for example, a coil used for a method operating by induction. The cooling member 26, according to the geometrical shape shown in FIG. 5, preferably penetrates into the blind hole-shaped cavity of the housing 12 of the supercharging system 10, in particular in the form of an exhaust gas turbocharger. As the sensor element 22 is housed in the opening of the wall of the housing 12, there is thus a reading zone for the sensor 22 of the rotational speed detection installation 14 which is very close to the fins 11 of the supercharging system 10, in particular as an exhaust gas turbocharger. This allows a detection as accurate as possible of the rotational speed of the compressor of the supercharging system 10.

FIG. 5 further shows that the cooling member 26 whose bottom has an opening is housed in a cavity 12 of the supercharging installation 10. Between the inner side of the cooling member 26 and the outer side of the rotational speed detection installation 14, in particular of the sensor body 21 as well as of the sensor 22, there will be an isolation air gap 28. This air gap also exists between the front face of the sensor 22 and the residual thickness 56 of the wall of the housing 12. In the variant embodiment of the rotational speed detection installation 14 according to the invention, as represented in FIG. the distance between the fins 11, in particular those of a rotor of

12 and the sensor 22 while having an isolation air gap 28 between the front face of the sensor 22 and the residual thickness 56 of the wall of the housing 12. The representation of FIG. operating electronics 52 housed in the rotational speed detection installation 14 is electrically connected by an electrical rail 50. The integrated operating electronics 52 use, for example, the principle of induction according to the design. of the rotational speed detection installation 14. FIG. 6 shows another alternative embodiment of the solution proposed by the invention. According to FIG. 6, the cooling member 58, preferably made of metal, is partially overmoulded by injection into the rotational speed detection installation 14 with the sensor body 21, the sensor 22, the sensor head 23 The connection outlet protrudes beyond the plastic material of the rotational speed detection installation 14. The sensor flange 16, according to another variant embodiment, is also made of metal to be integrally connected to the cooling member 58. by a connection preferably thermal and mechanical. In the alternative embodiment shown in FIG. 6, the cooling member made of metal is integrated by injection into the plastic material, which gives a block generally carrying the reference 60. The lower side by which the cooling member 58 is pressed against the housing 12 of the supercharger has a curved surface 62 or a fillet to have a direct contact only between the rotational speed detection installation 14, that is to say the 22 and the housing 12, but so that the cooling member 58 does not directly touch the housing 12. As another variant, we can consider a combination of the variants of Figure 5 and Figure 6. In this case , the injection-molded cooling member 58 enters the housing 12 of the turbocharger-type supercharger.35 NOMENCLATURE

10 Supercharger plant 11 Compressor rotor blade 12 Housing 14 Rotating speed detection system 16 Sensor flange 17 Rotor shaft of the compressor rotor 18 Mounting medium 20 Connection output 21 Sensor housing 22 Sensor 23 Head of sensor sensor 24 Cup 25 Cup bottom 26 Cooling element 28 Isolation air gap 30 Spreader 32 Fastening element 33 Fastening plate 34 Magnet 35 Cooling fin 44 Extrusion press profile 46 Cooling fin 50 Rail electrical 52 Operating electronics 56 Residual wall thickness of housing 58 Cooling element 60 Plastic block 62 Curved surface35

Claims (1)

CLAIMS1 »Rotational speed detection system (14) for a supercharging system (10), in particular an exhaust gas turbocharger of an internal combustion engine, * the supercharging plant (10) having a housing (12), a detection device (14) characterized in that it comprises a sensor element (22) to which is associated a metal cooling member (26, 58). 2 »rotational speed detection device according to claim 1, characterized in that the cup-shaped cooling member (26) surrounds the sensor (22). 3 »rotational speed detection device according to claim 1, characterized by an isolation air gap (28) between the sensor body (21) and the sensor (22) and / or the envelope surface and / or the bottom (25) of the cup-shaped cooling member (26) (24). 4 »rotational speed detection device according to claim 1, characterized in that the cooling member (26) comprises a number of cooling fins (35) extending in the radial direction. 5 »rotational speed detection device according to claim 4, characterized in that the cooling fins (35) of the cooling member (26) have different radial dimensions with respect to the sensor body (21). The rotational speed detection apparatus according to claim 3, characterized in that the sensor body (21) of the rotational speed detecting device (14) is supported by spacers (30) against the bottom (25) and / or the envelope surface of the cooling member (26) and the spacers (30) define the insulation gap (28). 7 »rotational speed detection device according to claim 3, characterized in that the sensor body (21), including the sensor (22), is surrounded by a press-extruded profile (44) having ribs cooling means (46) radially directed. The rotational speed detection device according to claim 1, characterized in that the sensor is housed in a cooling member (26) and the reading point of the sensor (22) is in a housing cavity. (12) of the supercharging plant (10). 9 »Rotational speed detection device according to claim 1, characterized in that the sensor body (58) is metal injection-molded with plastic and integrated in the plastics material. 10 »rotational speed detection device according to claim 1, characterized in that the cooling member (26) has an aperture in its bottom receiving the sensor (22) to minimize the distance from the sensor. boundary wall (56) in a cavity of the housing (12) of the supercharging plant (10).