Piezoelectric relief sensor for automotive vehicles
The piezoelectric sensor addresses the challenge of rotor temperature measurement errors by enabling remote, accurate temperature sensing in electric motors, enhancing control performance and eliminating electromagnetic interference.
Patent Information
- Authority / Receiving Office
- FR · FR
- Patent Type
- Applications
- Current Assignee / Owner
- CONTINENTAL AUTOMOTIVE TECHNOLOGIES GMBH
- Filing Date
- 2024-11-22
- Publication Date
- 2026-05-29
AI Technical Summary
Direct measurement of rotor temperature in electric motors is difficult due to rotation, leading to measurement errors of up to ±20°C using integrated algorithms, which can result in motor damage or failure.
A piezoelectric sensor with a fluid evacuation channel and a piezoelectric element that receives ultrasonic power signals, measures parameters, and converts them into ultrasonic response signals, allowing remote measurement without wired probes, and eliminating the need for metallic barriers.
Enables accurate temperature measurement near magnets, improving motor control performance by reducing measurement errors and eliminating electromagnetic interference, while facilitating sensor insertion and fluid evacuation.
Smart Images
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Abstract
Description
Title of the invention: Relief piezoelectric sensor for motor vehicles technical field
[0001] The present invention relates to the automotive field and more particularly concerns a relief piezoelectric sensor for motor vehicles. Prior art
[0002] As is known, an electric motor comprises a rotor and a stator. The operation of such a motor causes the rotor and stator to heat up. However, the rotor's temperature rise can lead to performance losses and demagnetization of the magnets inside it beyond a certain temperature, which can result in damage or even motor failure. It is therefore necessary to measure the temperature inside the rotor in order to reduce its speed when the temperature approaches the critical operating limit and thus prevent damage to the motor or its failure.
[0003] Due to its rotation during operation, the rotor temperature is difficult to measure directly by wired temperature probes, therefore it is estimated by algorithms and models integrated into the motor management system.
[0004] However, these integrated algorithms and models result in measurement errors of up to plus or minus 20°C, which is not satisfactory for controlling the motor in order to avoid damaging it or causing its failure.
[0005] A simple, reliable and effective solution that would at least partially remedy these drawbacks would therefore be advantageous. Description of the invention
[0006] To this end, the invention first relates to a sensor for measuring a parameter for a motor vehicle, said sensor comprising an elongated body having at least one lateral face extending between a distal end, having a raised shape extending projecting from said at least one lateral face, and a proximal end, said body comprising along at least one lateral face at least one fluid evacuation channel extending from the distal end to the proximal end, said sensor further comprising a piezoelectric element and a measuring element, said piezoelectric element being mounted inside the body adjacent to the distal end and being configured to receive an ultrasonic power signal and to electrically power said measuring element from said ultrasonic power signal,the measuring element being mounted inside the body, being electrically connected to the piezoelectric element and being, configured to, when electrically powered by the piezoelectric element, measure the parameter, generate a measurement signal representative of the value of said parameter at a given instant and transmit said measurement signal to the piezoelectric element, said piezoelectric element being configured to convert said measurement signal into an ultrasonic response signal and emit said ultrasonic response signal.
[0007] At least one channel allows fluid to be evacuated when the sensor is inserted into a receiving space, for example formed in a rotor or in a housing.
[0008] The sensor according to the invention enables remote measurements via the remote module by powering the sensing element with energy from signals sent by the main module over a wireless link. Thus, measurements can be taken very close to the magnets, thereby increasing the performance of the electrical machine control. The invention also eliminates the need for metallic barriers such as, for example, the housing and protective flanges, which block electromagnetic waves of the Wifi or Bluetooth type. The sensor according to the invention is easy to insert into a receiving space thanks to its profiled distal end, which also allows fluids to be expelled from said receiving space.The fluid evacuation channel(s) allow fluids, particularly air, to be evacuated to the outside when the sensor is inserted into the receiving space, in order to improve the quality of the emission and reception of ultrasonic signals by the piezoelectric element.
[0009] Preferably, the sensor further comprises a conduction element connecting the measuring element to the outside of the sensor, preferably by one of its lateral faces.
[0010] In one embodiment, the conduction element is a thermal conduction element, preferably made of aluminum or copper.
[0011] Advantageously, the piezoelectric element extends along a plane.
[0012] Preferably, the plane is orthogonal to the longitudinal axis of the sensor body.
[0013] According to one aspect of the invention, the distal end has a concave or pointed shape, for example conical.
[0014] In one embodiment, at least one drainage channel is a groove formed on the surface of the sensor body or a conduit formed in a lateral face of the sensor body.
[0015] The invention also relates to a sensor housing, said housing comprising a molded material delimiting a receiving space in which a sensor as presented above is mounted.
[0016] Preferably, the housing includes a magnet embedded in the molding material so as to be flush with the receiving space.
[0017] The invention also relates to an electric machine for a motor vehicle, said electric machine comprising a stator, a rotor and a sensor as previously presented, said electric machine being configured to be mounted in said vehicle in order to drive the wheels of said vehicle in rotation, electric machine in which the main module is mounted on the stator and the sensor is mounted inside the rotor.
[0018] The invention also relates to a battery or a group of batteries or a fuel cell for a motor vehicle, comprising a measuring sensor as previously described, the sensor being mounted respectively inside said battery or inside at least one battery of the group of batteries or inside the fuel cell.
[0019] The invention also relates to a motor vehicle comprising a sensor as previously described.
[0020] The invention also relates to a motor vehicle comprising an electric machine as presented above or a battery as presented above or a group of batteries as presented above or a fuel cell as presented above.
[0021] The invention also relates to a method of mounting a sensor as described above in a receiving space of a motor vehicle, said receiving space being dimensioned to receive said sensor without play, said method comprising the steps of:
[0022] - application of glue at least on the distal end of the sensor body,
[0023] - insertion of the distal end of the sensor into the receiving space,
[0024] - when the distal end of the sensor reaches the bottom of the receiving space, evacuation of fluids present in the receiving space by at least one evacuation channel so as to fix the sensor in the receiving space.
[0025] The invention also relates to a method for measuring a parameter using a sensor as described above, said method comprising the steps of:
[0026] - emission, by the main piezoelectric transceiver, of an ultrasonic signal power supply to the sensor,
[0027] - reception, by the piezoelectric element of the sensor, of the ultrasonic signal power supply emitted,
[0028] - power supply, via the piezoelectric element, to the measuring element using the electrical energy contained in the received ultrasonic power supply signal,
[0029] - measurement, by the measuring element, when it is electrically powered by the element piezoelectric, of the parameter,
[0030] - generation, by the measuring element, of a measurement signal representative of the value of said parameter at the given moment,
[0031] - transmission, by the measuring element, of said measuring signal to the element piezoelectric,
[0032] - conversion, by the piezoelectric element, of the measurement signal into an ultrasonic signal in response,
[0033] - emission, by the piezoelectric element, of said ultrasonic response signal,
[0034] - reception, by the main piezoelectric transceiver, of the ultrasonic signal of response issued,
[0035] - transmission, by the main piezoelectric transceiver, of the ultrasonic signal of the response received at the control level,
[0036] - determination, by the control stage, in the received ultrasonic measurement signal, of the measured temperature value.
[0037] Advantageously, the method includes a step of controlling, by the control stage, the rotor speed as a function of the determined temperature value. Brief description of the drawings
[0038] Other features and advantages of the invention will become apparent from the following description. This description is purely illustrative and should be read in conjunction with the accompanying drawings, in which:
[0039] [Fig-1] Fig. 1 is a schematic longitudinal cross-sectional view of a shape of realization of the sensor according to the invention.
[0040] [Fig.2] The [Fig.2] is a schematic longitudinal sectional view of a receiving space formed in a rotor and comprising the sensor of the [Fig.1].
[0041] [Fig.3] The [Fig.3] is a schematic longitudinal cross-sectional view of one embodiment of the electric machine according to the invention.
[0042] [Fig.4] Fig.4 schematically illustrates an example of three-step mounting of the sensor in a housing.
[0043] [Fig.5] Fig.5 schematically illustrates one embodiment of the assembly method according to the invention.
[0044] [Fig.6] Fig.6 schematically illustrates one embodiment of the measurement method according to the invention. Description of the implementation methods
[0045] Fig. 1 represents an example of a sensor 1 according to the invention and the figure an example of a receiving space 2A comprising the sensor 1.
[0046] The sensor 1 allows the measurement of a parameter such as, for example, temperature, pressure, torque, force or any other parameter that it is necessary to measure.
[0047] Sensor 1 is intended to be mounted in a motor vehicle.
[0048] Preferably, and as given by way of example in the remainder of this description, the sensor 1 is intended to be mounted in a machine rotor 320 electric 300 motor vehicle, as illustrated in [Fig.3] which will be described below.
[0049] The sensor 1 comprises a body 10, a piezoelectric element 20 and a measuring element 30.
[0050] The body 10 is at least partially hollow and has an elongated shape, for example tubular or parallelepiped-shaped. In the example shown in the figures, the body 10 has a circular cross-section.
[0051] The body 10 comprises a lateral face 110 extending between a proximal end 120P and a distal end 120D.
[0052] The distal end 120D has a raised shape extending outward from the lateral face 110. In the example of [Fig.1], the distal end 120D has a conical shape.
[0053] The body 10 comprises two fluid drainage channels, shown in the example of [Fig. 1] as two conduits 130 extending from the distal end 120D to the proximal end 120P, opening to the outside at each end. These conduits 130 allow the drainage of both liquids such as, for example, water or glue, and air.
[0054] The piezoelectric element 20 is mounted inside the body 10 adjacent to the distal end 120D.
[0055] In the example of [Fig.2], the piezoelectric element 20 is placed behind the distal end cone 120D and extends along a plane P orthogonal to the longitudinal axis X of the body 10 of the sensor 1 in order to improve the reception and transmission of ultrasonic signals with a main piezoelectric transceiver 310P of the stator 310 ([Fig.3]) as will be explained below.
[0056] The piezoelectric element 20 is configured to receive an ultrasonic power supply signal SUA (referenced on [Fig.6]) and to electrically supply the measuring element 30 from said ultrasonic power supply signal SUA.
[0057] The measuring element 30 includes an electrical circuit board 31 mounted inside the body 10 and electrically connected to the piezoelectric element 20 via an electrical connector 25.
[0058] The measuring element 30 is configured to, when electrically powered by the piezoelectric element, measure the parameter, generate a measurement signal S (referenced on [Fig.6]) representative of the value of said parameter at a given instant and transmit said measurement signal S to the piezoelectric element 20.
[0059] In the example of [Fig. 2], the measuring element 30 comprises a resistor 32 (or a thermistor) mounted on the electrical circuit board 31 and whose resistance varies with temperature. The measuring signal S is in this case the voltage applied across the terminals of said resistor 32 (or said thermistor).
[0060] The piezoelectric element 20 is configured to convert the measurement signal S into an ultrasonic response signal SUR (referenced in [Fig.6]) and to emit said ultrasonic response signal SUR to the main piezoelectric transceiver 310P of the stator 310. In other words, the piezoelectric element 20 is configured to emit the measurement signal S in the form of an ultrasonic signal.
[0061] In the example of [Fig.2], the sensor 1 further comprises an element of conduction 40 connecting the measuring element 30 to the outside of the sensor 1 via the lateral face 110. Preferably, this conduction element 40 is in the form of a blade, a rod or a bar, in particular made of metal.
[0062] When the sensor 1 is a temperature measuring sensor, as illustrated in this example, the conduction element 40 is a high thermal conduction element, for example made of aluminium or copper, in order to efficiently conduct heat to the measuring element.
[0063] Still with reference to [Fig.2], the sensor 1 is mounted in a receiving space 2A formed in the rotor 320 of the electric machine 300 to measure the temperature of a magnet of the rotor 320, in particular when said rotor 320 is driven in rotation.
[0064] The receiving space 2A has dimensions substantially equal to or slightly greater than those of the sensor 1 so that the sensor 1 can be housed without play, for example by force, in the receiving space 2A.
[0065] Still with reference to [Fig.2], the rotor 320 includes a coated magnet 2B flush with the receiving space 2A at the point where the conduction element 40 opens so that the temperature measured by the measuring element 30 is that of the magnet 2B and in particular varies with that of the magnet 2B via the thermal conduction element 40.
[0066] Fig. 3 illustrates an example of an electrical machine 300 comprising a receiving space in which a sensor 1 is housed as described above.
[0067] Figure 3 is an example of an electric machine 300 for a motor vehicle. The electric machine 300 is configured to be mounted in the vehicle in order to drive the wheels of said vehicle in rotation.
[0068] The electric machine 300 comprises a stator 310, a rotor 320 and a sensor 1 as previously presented.
[0069] The rotor 320 is configured to rotate around a longitudinal axis Y.
[0070] In this example, the rotor 320 includes a material shaft 321 extending along the longitudinal axis Y of rotation and comprising a first portion of axis 321A and a second portion of axis 321B connected to the stator 310 by means of a bearing system 315.
[0071] The stator 310 includes a control stage 31 OC and a main piezoelectric transceiver 31 OP configured to transmit the ultrasonic power signal SUA to the sensor 1 and to receive the ultrasonic response signal SUR.
[0072] Advantageously, the sensor 1 is mounted so that the piezoelectric element 20 extends in a plane P parallel to the plane P' of the main piezoelectric transceiver 310P to promote the exchange of ultrasonic signals.
[0073] The control stage 310C is configured to control the position of the rotor 320 and the temperature from the value of the parameter contained in the SUR response ultrasonic signal received by the main piezoelectric transceiver 310P.
[0074] It should be noted that the sensor could be used for other applications, for example in a battery or a group of batteries or a fuel cell.
[0075] Example of sensor mounting
[0076] First, with reference to Figures 4 and 5, in a step 11, glue is applied to the distal end 120D of the body 10 of the sensor 1 and optionally to the lateral face 110 of the body 10 of the sensor 1.
[0077] The sensor 1 is then fully inserted into the receiving space 2A in a step E2, the distal end 120D entering the receiving space 2A first ([Fig.4], left).
[0078] As the distal end 120D progresses through the receiving space 2A, and particularly when it reaches the bottom of the receiving space 2A, fluids such as air 3 and possibly excess glue and / or water present in the receiving space 2A are evacuated through the drainage channels 130 in a step E3 so that the sensor 1 completely occupies the receiving space 2A without any play, especially at the distal end 120D ([Fig. 4], center). In other words, the conical distal end 120D directs the fluids towards the drainage channels 130 as the sensor 1 is inserted into the receiving space 2A, and in particular expels the air that could otherwise interfere with the reception and transmission of ultrasonic signals by the piezoelectric element 20.
[0079] Once fully inserted into the receiving space 2A, without residual play, the glue dries and fixes the sensor 1 to the walls of the receiving space 2A so that it remains securely fixed in the rotor 320, in particular when the rotor 320 is driven in rotation ([Fig.4], right).
[0080] Example of implementation in the case of an electrical machine
[0081] With reference to [Fig. 6], when a temperature measurement is to be taken by the sensor 1, particularly when the rotor 320 is being rotated, the control stage 310C commands the emission, by the main piezoelectric transceiver 310P, of an ultrasonic power supply signal SUA to the sensor 1 in a step FL
[0082] The piezoelectric element 20 of the sensor 1 receives the ultrasonic power supply signal SUA in a step F2 and then electrically supplies the measuring element 30 with the electrical energy contained in the ultrasonic power supply signal SUA received in a step F3.
[0083] The measuring element 30, when electrically powered by the piezoelectric element 20, measures the parameter in a step F4 and generates a measurement signal representative of the value of said parameter at the given instant in a step F5, which it transmits to the piezoelectric element 20 in a step F6. In this example, the resistance of the resistor 32 varies according to the temperature of the magnet 2B connected to the measuring element by the conduction element 40, and the resistance value of the resistor 32 therefore corresponds to a given temperature, predetermined, for example, empirically. The measurement signal S then corresponds to the signal representing the voltage measured across the resistor 32.
[0084] The piezoelectric element 20 then converts the measurement signal S into an ultrasonic signal with SUR response in a step F7 and then emits said ultrasonic signal with SUR response in a step F8.
[0085] The SUR response ultrasonic signal is received by the main piezoelectric transceiver 310P in a stage F9 and then transmitted to the control stage 310C in a stage F10.
[0086] The control stage 310C then analyzes the received SUR measurement ultrasonic signal to determine the measured temperature value in a step Fl 1 and then controls the position of the rotor 320, in a manner known per se, as a function of the determined temperature value, for example using a predetermined lookup table stored in its memory area and giving the temperature value as a function of the voltage value given in the SUR response ultrasonic signal, in a step F12.
[0087] The invention therefore makes it possible to measure a parameter using a remote module powered remotely by electrical energy, thus avoiding the use of a battery to be changed, which is particularly advantageous in the case of an electric machine rotor.
Claims
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6. Demands A sensor (1) for measuring a parameter for a motor vehicle, said sensor (1) comprising an elongated body (10) having at least one lateral face (110) extending between a distal end (120D), having a raised shape projecting from said at least one lateral face (110), and a proximal end (120P), said body (10) having along at least one lateral face (110) at least one fluid discharge channel (130) extending from the distal end (120D) to the proximal end (120P), said sensor (1) further comprising a piezoelectric element (20) and a measuring element (30), said piezoelectric element (20) being mounted inside the body (10) adjacent to the distal end (120D) and being configured to receive an ultrasonic power signal (UPS) and to supply power said measuring element (30) from said ultrasonic power signal (UAS),the measuring element (30) being mounted inside the body (10) and electrically connected to the piezoelectric element (20) and configured to, when electrically powered by the piezoelectric element (20), measure the parameter, generate a measurement signal (S) representative of the value of said parameter at a given instant and transmit said measurement signal (S) to the piezoelectric element (20), said piezoelectric element (20) being configured to convert said measurement signal (S) into an ultrasonic response signal (URS) and emit said ultrasonic response signal (URS). Sensor (1) according to claim 1, further comprising a conduction element (40) connecting the measuring element (30) to the outside of the sensor (1), preferably by one of its lateral faces (110). Sensor (1) according to the preceding claim, wherein the conduction element (40) is a thermal conduction element, preferably made of aluminum or copper. Sensor (1) according to any one of the preceding claims, wherein the piezoelectric element (20) extends along a plane (P). Sensor (1) according to any one of the preceding claims, wherein the distal end (120D) has a pointed shape. Sensor (1) according to any one of the preceding claims, wherein at least one discharge channel is a groove formed on the surface of the body (10) of the sensor (1) or a conduit (130) formed in a lateral face (110) of the body (10) of the sensor (1).
7. Housing for a sensor (1) according to any one of claims 1 to 6, said housing (2) comprising a molding of material delimiting a space in which said sensor (1) is mounted.
8. Electric machine (300) for motor vehicle, said electric machine (300) comprising a stator (310), a rotor (320) and a sensor (1) according to any one of claims 1 to 6, said electric machine (300) being configured to be mounted in said vehicle in order to drive the wheels of said vehicle in rotation, electric machine (300) in which a main piezoelectric transceiver (310P) configured to transmit the ultrasonic power signal (SUA) to the sensor (1) and to receive the ultrasonic response signal (SUR) is mounted on the stator (310) and the sensor (1) is mounted inside the rotor (320).
9. Motor vehicle comprising a sensor (1) according to any one of claims 1 to 6.
10. Method of mounting a sensor (1) according to any one of claims 1 to 6 in a receiving space (2A) of a motor vehicle, said receiving space (2A) being dimensioned to receive said sensor (1) without play, said method comprising the steps of: - application (E1) of an adhesive at least on the distal end (120D) of the body (10) of the sensor (1), - insertion (E2) of the distal end (102D) of the sensor (1) into the receiving space (2A), - when the distal end (120D) of the sensor (1) reaches the bottom of the receiving space (2A), evacuation (E3) of the fluids present in the receiving space (2A) through at least one evacuation channel (30) so as to fix the sensor (1) in the receiving space (2A).