A method and system for predicting the remaining service life of a braking member of a vehicle, in terms of remaining available mileage

Abstract

The remaining service life of a braking member of a vehicle, in terms of the remaining available mileage, is estimated on the basis of monitoring the progression of wear and temperature of the braking member as result of vehicle use. Successive wear levels and the temperature of the braking member are monitored through a sensor (2) of wear and temperature of a braking member of a vehicle comprising detection electric circuits (12) arranged in ordered sequence. The electronic control unit of the vehicle associates the interruption of a given detection electric circuit (12) to a corresponding value of a dimension of the braking member which is subject to decrease due to wear and detects the vehicle mileage at the installation of the braking member and at each subsequent detection of a given level of wear of the braking member. In this way, after each detection of a certain level of wear of the braking member, the stored data on the detected mileages and corresponding values of said dimension of the braking member can be used to estimate the remaining service life of the braking member in terms of the remaining mileage available before a predetermined minimum value of said dimension of the braking member is reached.

Description

[0001] “A method and system for predicting the remaining service life of a braking member of a vehicle, in terms of remaining available mileage” ****

[0002] TEXT OF THE DESCRIPTION

[0003] Field of the invention

[0004] The present invention relates to a method and a system for predicting the remaining service life of a braking member of a vehicle, for example a disk brake pad or a lining for a drum brake shoe, or other friction braking member. The invention relates in particular to a method and a system for predicting the remaining service life of a braking member, in terms of the remaining mileage that can be traveled by the vehicle, based on monitoring the progression of wear and temperature of the braking member,

[0005] Prior art

[0006] Detection units for the wear and temperature of a braking member (also referred to as “brake pad” hereinafter, for brevity only) are known in the art, for example from document EP 3948007 B1. Figure 1 schematically illustrates two opposite end portions of the known detection unit, with parts removed for clarity (such as the intermediate part). The detection unit 1 includes a detection sensor 2, an electric connector 3 for connecting the detection unit 1 to an electronic control unit (ECU) of the vehicle, and an electric wiring 4 for connecting the detection sensor 2 to the electric connector 3. The detection sensor 2 comprises a body 5, preferably cylindrical, which is configured to be inserted and locked into a recess of the brake pad in such a way that the longitudinal axis 6 of the sensor 2 extends orthogonally to the rubbing surface 7 between the pad and the disk. The detection unit 1 comprises a flexible strip 8 (for example, polymeric) which has a first end part 9 embedded in the body 5 of the sensor 2, a second end part 10 opposite to the first which extends inside the electric connector 3 of the detection unit 1 , and an intermediate section 11 which extends between the body 5 of the sensor 2 and the electric connector 3. On the first end part 9 of the flexible strip 8, embedded in the sensor 2, a row of independent detection electric circuits 12 is arranged. The detection electric circuits 12 are arranged in cascade along the longitudinal axis 6 of the sensor 2 starting from its front surface 7 (i.e. , the surface facing the disk brake) and are made by depositing electrically conductive material on an outer surface of the flexible strip 8. The detection electric circuits 12 have respective first ends 13 all electrically coupled to a conductive track 14 arranged in the body 5 of the sensor 2 parallel to the longitudinal axis 6, and second ends 15 electrically isolated amongst each other. The first ends 13 of the detection circuits 12 are polarized to a first voltage V- received via the electric connector 3, and the second ends 15 of the detection circuits 12 are polarized to a second voltage V+ received via the electric connector 3. Each detection circuit 12 comprises a wear detector 16, i.e. a section of the circuit 12 which, when worn due to the progressive wear of the brake pad in which the sensor 2 is arranged, opens the relative circuit 12 (i.e., electrically isolates the first end 13 from the second end 15 of the circuit 12). Each detection circuit 12 (or a subset thereof) also comprises a temperature detector 17 (e.g., a resistance thermometer). An electronic control unit 18 (e.g., a microprocessor) is electrically connected to the detection circuits 12 so as to emit, during the wear of the brake pad, an output signal S which depends on the wear and temperature of the pad itself. In particular, wear is determined by the microprocessor 18 by detecting the electric continuity at the ends of the detection circuits 12, which will be progressively interrupted due to wear. The temperature is determined as a function of the resistance value of the resistance thermometer arranged in the intact detection circuit 12 which from time to time is closest to the rubbing surface 7 between the pad and the disk.

[0007] Additional sensors for detecting wear and temperature of a braking member are described in US 2018 / 0128334 A1 and US 5559286 A.

[0008] In the known sensor described above, errors may occur in reading the wear value and / or temperature of the brake pad due to possible faults in the sensor itself (for example, the interruption of one or more of the detection circuits due to causes other than wear). In such cases, the information provided to the driver of the vehicle is incorrect.

[0009] In order to overcome these drawbacks, in the Italian patent application IT 10 2023 000001701 filed on 02 / 02 / 2023 and still secret at the date of filing of the present application, the Applicant has proposed a method and a unit for detecting wear and temperature of a braking member that are able to provide more reliable detections than the solutions of the prior art, being able to also detect any faults in the sensor used for the detection.

[0010] However, there is a need to further improve the aforementioned solution, in order to obtain new functionalities, in particular with reference to the possibility of signaling to the driver, with a relatively high precision, the expected duration of the braking member, in terms of remaining mileage that the vehicle can travel before it is necessary to provide for a replacement of the braking member.

[0011] Object of the invention

[0012] The object of the present invention is therefore to improve the solution proposed in the aforementioned previous Italian patent application IT 10 2023 000001701 of the Applicant, in order to obtain new functionalities, in particular with reference to the possibility of signaling to the driver, with a relatively high precision, the expected duration of the braking member, in terms of remaining mileage that the vehicle can travel before it is necessary to provide for a replacement of the braking member.

[0013] Summary of the invention

[0014] According an aspect, the invention relates to a method for predicting the remaining service life of a braking member of a vehicle, in terms of remaining available mileage, based on monitoring the progression of wear and temperature of said braking member as result of vehicle use,

[0015] - wherein successive wear levels and temperature of said braking member are monitored through the following operations: a) detecting the resistance values of a set of detection electric circuits arranged in ordered sequence along an axis of a detection sensor, wherein each of said detection electric circuits comprises a respective wear detector of the braking member, and each detection electric circuit in a subset of said detection electric circuits comprises a respective temperature detector of the braking member, wherein a first detection electric circuit of said ordered sequence is arranged toward a rubbing surface of said braking member and, a last detection electric circuit of said ordered sequence is arranged toward a support back plate of said braking member; b) producing a N-bit binary sequence, N being the number of said detection electric circuits, wherein the bits of said binary sequence are orderly associated, from a most significant bit to a least significant bit, to said ordered sequence of detection electric circuits, and wherein each bit of said binary sequence takes a first logic value if the corresponding detection electric circuit is electrically continuous and a second logic value if the corresponding detection electric circuit is electrically interrupted; c) identifying, in said N-bit binary sequence, a most significant bit amongst the bits having said first logic value, and determining the wear degree of said braking member as a function of the position of said identified bit in said binary sequence; d) identifying, in a subset of said N-bit binary sequence corresponding to said subset of detection electric circuits, a further most significant bit amongst the bits having said first logic value, and determining the temperature of said braking member as a function of the resistance of the temperature detector associated to the detection electric circuit corresponding to said further most significant bit; e) storing a set of allowable cases for said N-bit binary sequence; f) comparing said N-bit binary sequence to said stored allowable cases; and g) producing an error message if said N-bit binary sequence does not correspond to any of said stored allowable cases, and wherein the following operations are also provided:

[0016] - associating the interruption of a given detection electric circuit to a corresponding value of a dimension of the braking member which is subject to decrease due to wear

[0017] - detecting, at an electronic control unit of the vehicle, the vehicle mileage at the installation of the braking member and at each subsequent detection of a given level of wear of the braking member corresponding to the interruption of a given detection electric circuit,

[0018] - storing the different mileages so detected and the corresponding values of said dimension of the braking member,

[0019] - in such a way that after each detection of a given level of wear of the braking member, the stored data on the detected mileages and corresponding values of said dimension of the braking member are used to estimate the remaining service life of the braking member in terms of remaining mileage available before a predetermined minimum value of said dimension of the braking member is reached.

[0020] According to another aspect, the invention relates to a system for predicting the remaining service life of a braking member of a vehicle, in terms of the remaining available mileage, based on monitoring the progression of wear and temperature of said braking member as result of vehicle use, wherein said system includes a detection unit for monitoring successive wear levels and temperature of said braking member, wherein said detection unit includes a detection sensor, an electric connector configured to connect the detection unit to an electronic control unit of the vehicle, and an electric wiring configured to connect the detection sensor to the electric connector; wherein the detection sensor comprises:

[0021] - a body having a longitudinal axis and configured to be inserted into the braking member; and

[0022] - a set of detection electric circuits arranged in said body in an ordered sequence along said longitudinal axis, said detection electric circuits having respective first terminals all electrically coupled to a conductive track arranged in said body of the detection sensor and configured to receive a first power supply voltage, and respective second terminals electrically isolated amongst each other and configured to receive a second power supply voltage, wherein each of said detection electric circuits comprises a respective wear detector of said braking member, and each of said detection electric circuits in a subset of said detection electric circuits comprises a respective temperature detector of said braking member, wherein a first detection electric circuit of said ordered sequence is arranged toward a rubbing surface of said braking member and a last detection electric circuit of said ordered sequence is arranged toward a support back plate of said braking member; and wherein the electric connector comprises a microprocessor coupled to said detection electric circuits to sense their respective resistance values and a transceiver coupled to said microprocessor, and configured to transmit a message indicative of the wear degree and temperature of said braking member to an electronic control unit of said vehicle, said microprocessor being configured for:

[0023] (a) detecting the resistance values of a set of detection electric circuits arranged in ordered sequence along an axis of a detection sensor, wherein each of said detection electric circuits comprises a respective wear detector of the brake member, and each detection electric circuit in a subset of said detection electric circuits comprises a respective temperature detector of the brake member, wherein a first detection electric circuit of said ordered sequence is arranged toward a rubbing surface of said brake member and a last detection electric circuit of said ordered sequence is arranged toward a support back plate of said brake member;

[0024] (b) producing a N-bit binary sequence, N being the number of said detection electric circuits, wherein the bits of said binary sequence are orderly associated, from a most significant bit to a least significant bit, to said ordered sequence of detection electric circuits, and wherein each bit of said binary sequence takes a first logic value if the corresponding detection electric circuit is electrically continuous and a second logic value if the corresponding detection electric circuit is electrically interrupted;

[0025] (c) identifying, in said N-bit binary sequence, a most significant bit amongst the bits having said first logic value, and determining the wear degree of said braking member as a function of the position of said identified bit in said binary sequence; d) identifying, in a subset of said N-bit binary sequence corresponding to said subset of detection electric circuits, a further most significant bit amongst the bits having said first logic value, and determining the temperature of said braking member as a function of the resistance of the temperature detector associated to the detection electric circuit corresponding to said further most significant bit; e) storing a set of allowable cases for said N-bit binary sequence; f) comparing said N-bit binary sequence to said stored allowable cases; and

[0026] (g) producing an error message if said N-bit binary sequence does not correspond to any of said stored allowable cases, the electronic control unit of the vehicle being also configured for: - associating the interruption of a given detection electric circuit to a corresponding value of a dimension of the braking member which is subject to decrease due to wear,

[0027] - detecting the vehicle mileage at the installation of the braking member and at each subsequent detection of a given level of wear of the braking member corresponding to the interruption of a given detection electric circuit,

[0028] - storing the different mileages so detected and the corresponding values of said dimension of the braking member,

[0029] - in such a way that after each detection of a given level of wear of the braking member, the stored data on the detected mileages and corresponding values of said dimension of the braking member can be used to estimate the remaining service life of the braking member in terms of remaining mileage available before a predetermined minimum value of said dimension of the braking member is reached.

[0030] According to another aspect, the invention relates to a corresponding computer program product loadable into a memory of at least one processing device (e.g., a microprocessor of the detection unit) and comprising software code instructions for executing the steps of the method according to one or more embodiments when the program is executed by the at least one processing device. As used herein, a reference to such a computer program product is intended to be equivalent to a reference to a computer-readable medium containing instructions for controlling the processing device in order to coordinate the implementation of the method according to one or more embodiments. A reference to “at least one processing device” is intended to highlight the possibility that one or more embodiments are implemented in a modular and / or distributed form.

[0031] Detailed description of the invention

[0032] Further features and advantages of the invention will be apparent from the following description with reference to the attached drawings, provided purely by way of non-limiting example, in which:

[0033] - figure 1 , described above, illustrates a unit for detecting the wear and temperature of a braking member according to the known art;

[0034] - figure 2 illustrates a unit for detecting the wear and temperature of a braking member according to one or more embodiments of the present invention;

[0035] - figure 3 illustrates a flow diagram of a method for detecting wear and temperature of a braking member according to one or more embodiments of the present invention,

[0036] - figure 4 illustrates a diagram of a vehicle provided with the system according to the invention, and

[0037] - figure 5 is a diagram illustrating the advantages of the invention.

[0038] The method and the system according to the invention are based on a detection of the wear and temperature of a braking member (e.g., a brake pad) through a detection unit, for example as illustrated in figure 2, in which parts corresponding to those of figure 1 are indicated with the same reference numbers, and are not described again here, for brevity. Furthermore, any differences in the dimensioning (e.g., in the proportions) of such parts between different figures must not be interpreted as implying a structural difference, but may be due (only) to a greater clarity of representation.

[0039] As described above, on the end part 9 of the flexible strip 8 embedded in the sensor 2 a row of independent detection electric circuits 12 is arranged. Each detection circuit 12 comprises a wear detector 16, optionally, a temperature detector 17 (e.g., a resistance thermometer). It will be noted that the presence of a wear detector 16 in each circuit 12 is almost implicit, since the electric continuity of each circuit 12 is in fact impaired by the progressive wear of the brake pad, regardless of the specific shape of the portion 16 of the circuit 12, here exemplified as a “V”. In the example considered here, the sensor 2 comprises:

[0040] - a first circuit 12 comprising a wear detector 16 and a resistance thermometer Te90, arranged at 90% of the usable thickness of the brake pad (starting from the surface 7 when the sensor 2 is intact);

[0041] - a second circuit 12 comprising a wear detector 16 and a conductive track Pi70, arranged at 70% of the usable thickness;

[0042] - a third circuit 12 comprising a wear detector 16 and a resistance thermometer Te50, arranged at 50% of the usable thickness;

[0043] - a fourth circuit 12 comprising a wear detector 16 and a conductive track Pi30, arranged at 30% of the usable thickness; - a fifth circuit 12 comprising a wear detector 16 and a resistance thermometer Te10, arranged at 10% of the usable thickness;

[0044] - a sixth circuit 12 comprising a wear detector 16 and a conductive track PiO, arranged at 0% of the usable thickness (i.e. , the usability limit of the brake pad, beyond which the pad must be replaced - e.g., when the residual thickness of the pad is in the order of 2.6 mm);

[0045] - a seventh circuit 12 comprising a wear detector 16 and a conductive track PiW, arranged between 0% of the usable thickness of the brake pad and the back plate (or support or support back plate) of the brake pad (e.g., at an alarm threshold); and

[0046] - an eighth circuit 12 comprising a wear detector 16 and a resistance thermometer TeBP, arranged at the back plate of the brake pad (e.g., at the end of the friction material of the brake pad, i.e. the eighth circuit can be “embedded” in the steel).

[0047] The electronic control unit 18 is electrically connected to the detection circuits 12 so as to emit, during the vehicle use and as a function of the progressive wear of the brake pad, an output signal S which depends on the wear and temperature of the pad itself. The electronic control unit 18 receives a power supply voltage between two power supply terminals V+ and V- (e.g., positive terminal and reference or ground or grounding terminal). The power supply voltage, possibly regulated and / or rescaled, is used to power the internal circuits of the unit 18 and to polarize the detection circuits 12. As described above, wear is determined by the unit 18 by detecting the electric continuity across the detection circuits 12. In particular, the unit 18 comprises a microprocessor 180 and a LIN (Local Interconnect Network) transceiver 182. The microprocessor 180 is electrically coupled to the circuits 12 to sense their electric continuity (i.e., substantially, the resistance value), and executes an algorithm (e.g., implemented by the microprocessor firmware) that processes the data received from each circuit 12 and produces an output signal in the LIN format. The signal in the LIN format is transmitted to the LIN transceiver 182 and from there is transmitted as an output signal S to a vehicle control unit (ECU) via a LIN bus. The output signal S in particular transmits information about the sensor 2 identifier (by which the vehicle identifies the braking member from which the information comes, for example front left, front right, rear left or rear right), the wear degree of the brake pad, the temperature of the brake pad, and the detection of any faults in the sensor 2.

[0048] In particular, the microprocessor 180 is configured to associate to each detection circuit 12, based on its resistance value, a digital (logic) value indicative of the fact that the circuit is electrically continuous, i.e. intact (e.g., logic “1”) or is electrically interrupted, i.e. worn or damaged (e.g., logic “0”). The sequence of digital values produces a N-bit binary code, where N is the number of detection circuits 12 (e.g., 8 bits in the example of figure 2). In particular, the binary code can be structured so that the Most Significant Bit (MSB) is associated to the first circuit 12, i.e. the one closest to the surface 7, and the Least Significant Bit (LSB) is associated to the last (e.g., eighth) circuit 12, i.e. the one closest to the back plate of the brake pad. For example, when the brake pad is new and intact, the microprocessor 180 produces the binary code “11111111”, corresponding to the value 255 in base-10, as shown in Table I at the end of the description.

[0049] If, however, the brake pad is slightly worn and the detection circuit 12 closest to the disk brake (i.e., the circuit comprising the resistance thermometer Te90) is worn to the point of being electrically discontinuous (i.e., open), the microprocessor 180 produces the binary code “01111111”, corresponding to the value 127 in base-10, as shown in Table II at the end of the description.

[0050] Again by way of example, if the brake pad is worn to the limit of its usable thickness and the detection circuit 12 comprising the conductive track PiO is worn to the point of being electrically discontinuous, the microprocessor 180 produces the binary code “00000011”, corresponding to the value 3 in base-10, as shown in Table III at the end of the description.

[0051] Essentially, assuming that no errors or faults occur in sensor 2, only eight binary codes (and the corresponding eight numerical values in base- 10) are “acceptable” for microprocessor 180, i.e. the codes in which the bits with value “0” (if present) are consecutive and arranged starting from the most significant bit, as shown in Table IV at the end of the description. It will be noted that the code in which all the bits take value “0” is not considered acceptable, since the least significant bit indicates the electric integrity of circuit 12 corresponding to the back plate of the brake pad, which is not subject to wear (being “embedded” in the steel and not in the friction material of the pad).

[0052] Any other binary code (and any other numerical value in base-10) other than those listed in Table IV identifies a sensor operating error, as it indicates that a certain detection circuit 12 is open when at least one other detection circuit 12 which is closer to the contact surface 7 with the disk brake is still closed (or, in the case of a code with all bits equal to “0”, it would indicate wear of the circuit 12 embedded in the back plate - which cannot occur). For example, the binary code “11011111” would indicate the wear of the resistance thermometer Te50 when the resistance thermometer Te90 and the conductive track Pi70 are not yet worn, which is incompatible with the expected operation of the sensor 2, which wears progressively along the direction of the longitudinal axis 6 starting from the surface 7.

[0053] Therefore, as exemplified in the flow chart of figure 3, in a step 300 of the detection method 30 the microprocessor 180 is configured to store, in a respective memory area, the allowable numerical values (in base-10) in the form 2n-1 with n = 1 , ..., N (e.g., eight numerical values 1 , 3, 7, 15, 31 , 63, 127, 255 for N = 8).

[0054] In a step 302, the microprocessor 180 detects the electric continuity of the circuits 12 and produces the corresponding binary code, assigning the logic value “1” to each closed circuit and the logic value “0” to each open circuit, with the most significant bit (MSB) corresponding to the detection circuit closest to the rubbing surface 7 (e.g., the circuit comprising the resistance thermometer Te90) and the least significant bit (LSB) corresponding to the detection circuit closest to the back plate of the brake pad (e.g., the circuit comprising the resistance thermometer TeBP).

[0055] In a step 304, the microprocessor 180 determines the wear value of the brake pad by selecting the most heavily weighted bit (i.e., the most significant bit) amongst all the bits having a value of “1” in the binary code produced in step 302. The search for the most heavily weighted bit “1” may be performed in various ways, implemented by the firmware of the microprocessor 180. For example, the microprocessor may examine the values of the bits of the binary code starting from the most significant bit, and stop the search as soon as it detects a bit having a value of logic “1”. Alternatively, the microprocessor may multiply each bit of the binary code by a corresponding coefficient, such coefficients having respective values that increase as the significance of the bit increases (i.e. , the most heavily weighted coefficient being associated to the MSB and the least heavily weighted coefficient being associated to the LSB), thereby producing a set of weighted values; the wear value may then be selected as the value corresponding to the bit that produces the maximum of such weighted values. The coefficients can correspond to the base-10 value that would be encoded by the corresponding bit if the sensor were to function correctly (i.e., if all circuits 12 from the closest to the back plate to the nthwere closed). For example, Table V shown at the end of the description illustrates such possible coefficients associated to the bits of the binary code.

[0056] Once the wear degree of the brake pad has been identified by selecting the most significant bit amongst the bits having a logic value of “1” in the binary code produced in step 302, the microprocessor 180 determines the temperature of the brake pad in step 306 by selecting, as the reading sensor, the detection circuit 12 which includes a resistance thermometer and which corresponds to the bit with the greatest weight (i.e., the most significant one) amongst the bits having a logic value of “1” in the binary code produced in step 302. In other words, if the bit corresponding to the resistance thermometer Te90 is equal to “1”, the resistance thermometer Te90 is chosen as the temperature reading sensor. Next, if the bit corresponding to the resistance thermometer Te90 is equal to “0” and the bit corresponding to the track Pi70 is equal to “1”, the resistance thermometer Te50 is chosen if the corresponding bit is equal to “1”, alternatively the resistance thermometer Te10 if the corresponding bit is equal to “1”, and as a last alternative the resistance thermometer TeBP if the corresponding bit is equal to “1”. If the bit corresponding to the last resistance thermometer TeBP is also equal to “0” (which may correspond to an error or fault), the sensor determines that it is impossible to sense the temperature as all the resistance thermometers are out of order. Next, if the bit corresponding to the track Pi70 is equal to “0” and the bit corresponding to the resistance thermometer Te50 is equal to “1”, the resistance thermometer Te50 is chosen. Next, if the bit corresponding to the resistance thermometer Te50 is equal to “0” and the bit corresponding to the track Pi30 is equal to “1”, the resistance thermometer Te10 is chosen if the corresponding bit is equal to “1”, and alternatively the resistance thermometer TeBP if the corresponding bit is equal to “1”. If the bit corresponding to the last resistance thermometer TeBP is also equal to “0”, the sensor determines that it is impossible to sense the temperature as all the resistance thermometers are out of order. Next, if the bit corresponding to the track Pi30 is equal to “0” and the bit corresponding to the resistance thermometer Te10 is equal to “1”, the resistance thermometer Te10 is chosen. Next, if the bit corresponding to the resistance thermometer Te10 is equal to “0” and the bit corresponding to the track PiO or PiW is equal to “1”, the resistance thermometer TeBP is chosen if the corresponding bit is equal to “1”. If the bit corresponding to the last resistance thermometer TeBP is also equal to “0”, the sensor determines that it is impossible to sense the temperature because all the resistance thermometers are out of order.

[0057] In step 308, the microprocessor 180 calculates the base-10 value corresponding to the binary code produced in step 302, and compares it to the allowable numerical values stored in the memory area. If the calculated value corresponds to one of the allowable numerical values, the sensor is operating correctly (i.e., there is no “abnormal” interruption of the detection circuits 12). If the calculated value does not match any of the stored numerical values, then the sensor has a fault in at least one of the detection circuits 12, and an error message is produced, which is conveyed to the driver of the vehicle - together with the wear and temperature information - via the signal S.

[0058] As an example, the case in which the binary code produced at step 302 is equal to “11011111”, as shown in Table VI at the end of the description, is analyzed here. In this case, the detection unit indicates that the thickness of the brake pad is still greater than 90% of the usable thickness (since the circuit Te90 is electrically continuous) and detects the temperature based on the resistance of the resistance thermometer Te90 (again since the circuit Te90 is electrically continuous), but at the same time indicates to the driver that the sensor has a fault (since the circuit Te50 is electrically discontinuous even though the circuits Te90 and Pi70 are electrically continuous).

[0059] In the method and system according to the invention, the wear and temperature measurements of the braking member carried out with the method described above are used to obtain a prediction of the remaining service life of a braking member of a vehicle, in terms of remaining available mileage.

[0060] Figure 4 of the attached drawings shows a diagram of a vehicle provided with a system according to the present invention.

[0061] In figure 4, the references R1 , R2 indicate respectively the two front wheels and the two rear wheels of a vehicle, each of which is associated to a disk brake, respectively indicated by F1 , F2, F3, F4. Each of the disk brakes F1-F4 can be made according to any known technique and comprises a disk D rigidly connected to the wheel hub, so as to rotate with the wheel, and a brake caliper C carried by the structure of the vehicle (not illustrated) and suitable for engaging the disk D to slow its rotation. Also according to the prior art, the vehicle is provided with a braking device MC operated by a brake pedal P and connected hydraulically or electrically to a pressure modulator unit H that controls the supply of pressurized fluid to fluid actuators of the brake calipers C. One or more of the disk brakes F1- F4 have their respective brake calipers C with brake pads provided with detection units of the type described above forming part of the system according to the invention. The output signals from the detection units associated to the disk brakes F1-F4 are sent to the electronic control unit E of the vehicle.

[0062] According to the invention, the electronic control unit E is also configured to receive the output signals from an odometer OD of any known type, with which the vehicle is provided, capable of providing an indication of the kilometers traveled by the vehicle. Furthermore, the electronic control unit E is configured to store in a memory M associated to it (see figure 4) the values of the dimension of the braking member which is liable to decrease due to wear (in the case of a disk brake pad, the thickness of the brake pad) as wear progresses, starting from a nominal value of that dimension corresponding to the new braking member, as soon as it is installed. Each time the electronic control unit E receives from the detection unit of one of the disk brakes F1-F4, following the interruption of a certain detection electric circuit 12, a signal indicating that a certain level of wear of the respective brake pad has been reached, the electronic control unit E is configured to store in memory M the corresponding value of the current dimension of the braking member (i.e. the thickness of the brake pad) and to associate this value to the value of the kilometers travelled by the vehicle, reported by the odometer OD, after the detection of a previous level of wear (or after the installation of the brake pad if the current level of wear corresponds to the first level of wear after the installation of a new brake pad). The electronic control unit E is thus able to store in memory M the different detected mileages and the corresponding values of the thickness of the brake pad.

[0063] In this way, after each detection of a certain level of brake pad wear, the stored data on the detected mileages and corresponding brake pad thickness values can be used to estimate the remaining service life of the brake pad in terms of the remaining available mileage before reaching a predetermined minimum value of the brake pad thickness. The estimation of the remaining mileage that can be driven can be carried out according to any known extrapolation method. For example, after the installation of a new brake pad, the electronic control unit E signals a theoretical nominal service life value, which is stored in the memory M. After reaching a first level of wear, the electronic control unit can detect the kilometers actually driven and update the remaining service life as a first approximation according to a linear extrapolation that takes into account the total wearable thickness. After reaching a second level of wear, the electronic control unit can detect the kilometers traveled after reaching the second level of wear, determine the variation with respect to the linear extrapolation previously performed and thus calculate a correction coefficient to be applied to a new linear extrapolation, and so on. As indicated, the estimation method can be any. The estimate thus performed implicitly considers the real use of the braking member of the vehicle, updating itself at each wear step taking into account the more or less aggressive driving style, the load conditions and the route taken.

[0064] Figure 5 shows the results of the application of the method according to the invention in a practical case. The line T shows the kilometers traveled by the vehicle as the wear of a brake pad progresses. At kilometer zero, the thickness of the brake pad is 100% of the nominal value of the new pad just installed. In a road test, it was empirically found that the kilometers traveled when the brake pad was completely worn (0% of the nominal thickness) were 38683. Line R shows the decrease in the remaining mileage as the brake pad wear increases, as empirically found. Based on this practical test, when the brake pad was installed, the system should have reported a remaining mileage equal to the value that resulted in reality, i.e. 38683. For each successive level of wear, line R provides the value of the remaining mileage that the system should have reported to provide an accurate prediction of what was verified in reality. Finally, line D provides the values of the remaining available mileage as the wear progresses, as obtained with the system and the method of the invention. As is evident, the invention provides results that are close to the real data with a high degree of approximation.

[0065] Of course, notwithstanding the principle of the invention, the construction details and the embodiments may vary widely with respect to what is described and illustrated purely by way of example, without thereby departing from the scope of the present invention, as defined in the attached claims.

[0066] T able

[0067] Table III able IV Table VI

Claims

CLAIMS1. A method (30) for predicting the remaining service life of a braking member of a vehicle, in terms of remaining available mileage, based on monitoring the progression of wear and temperature of said braking member as result of vehicle use,- wherein successive wear levels and temperature of said braking member are monitored through the following operations: a) detecting (302) resistance values of a set of detection electric circuits (12) arranged in ordered sequence along an axis (6) of a detection sensor (2), wherein each of said detection electric circuits (12) comprises a respective wear detector (16) of the braking member, and each detection electric circuit (12) in a subset of said detection electric circuits (12) comprises a respective temperature detector (17; Te90, Te50, Te10, TeBP) of the braking member, wherein a first detection electric circuit (12, Te90) of said ordered sequence is arranged toward a rubbing surface (7) of said braking member and a last detection electric circuit (12, TeBP) of said ordered sequence is arranged toward a support back plate of said braking member; b) producing (302) a N-bit binary sequence, N being the number of said detection electric circuits (12), wherein the bits of said binary sequence are orderly associated, from a most significant bit to a least significant bit, to said ordered sequence of detection electric circuits (12), and wherein each bit of said binary sequence takes a first logic value if the corresponding detection electric circuit (12) is electrically continuous and a second logic value if the corresponding detection electric circuit (12) is electrically interrupted; c) identifying (304), in said N-bit binary sequence, a most significant bit amongst the bits having said first logic value, and determining the wear degree of said braking member as a function of the position of said identified bit in said binary sequence; d) identifying (306), in a subset of said N-bit binary sequence corresponding to said subset of detection electric circuits (12), a further most significant bit amongst the bits having said first logic value, and determining the temperature of said braking member as a function of theresistance of the temperature detector associated to the detection electric circuit (12) corresponding to said further most significant bit; e) storing (300) a set of allowable cases for said N-bit binary sequence; f) comparing (308) said N-bit binary sequence to said stored allowable cases; and g) producing (308) an error message if said N-bit binary sequence does not correspond to any of said stored allowable cases, said method also comprising the operations of:- associating the interruption of a given detection electric circuit (12) to a corresponding value of a dimension of the braking member which is subject to decrease due to wear- detecting, at an electronic control unit of the vehicle, the vehicle mileage at the installation of the braking member and at each subsequent detection of a given level of wear of the braking member corresponding to the interruption of a given detection electric circuit (12),- storing the different mileages so detected and the corresponding values of said dimension of the braking member,- in such a way that after each detection of a given level of wear of the braking member, the stored data on the detected mileages and corresponding values of said dimension of the braking member are used to estimate the remaining service life of the braking member in terms of the remaining available mileage before a predetermined minimum value of said dimension of the braking member is reached.

2. The method (30) of claim 1 , wherein the step of storing (300) said set of allowable cases for said N-bit binary sequence comprises storing the base-10 values corresponding to the sequences where the bits having said second logic value, if present, are consecutive and arranged starting from the most significant bit of said N-bit binary sequence, and wherein the step of comparing (308) said N-bit binary sequence to said stored allowable cases comprises comparing the base-10 value of said N-bit binary sequence to said stored base-10 values.

3. The method (30) of claim 1 or claim 2, comprising storing a lookup table between the position of the bit in said binary sequence and wear degree of the braking member, wherein the step of determining the weardegree of said braking member as a function of the position of said identified bit in said binary sequence comprises applying said lookup table.

4. The method (30) of any of the previous claims, wherein said first logic value is a logic “1” and said second logic value is a logic “0”, and wherein the step of identifying (304), in said N-bit binary sequence, the most significant bit amongst the bits having said first logic value comprises:- multiplying each bit of said binary sequence by a corresponding coefficient, said coefficients having respective values that increase as the significance of the bit of the binary sequence increases, producing a set of weighted values;- identifying the maximum value amongst said weighted values; and- selecting the bit of the binary sequence that produces said maximum value amongst said weighted values as the most significant bit amongst the bits having said first logic value.

5. The method (30) of any of the previous claims, wherein the step of identifying (304), in said N-bit binary sequence, the most significant bit amongst the bits having said first logic value comprises examining the values of the bits of said binary sequence starting from the most significant bit and stopping the search as soon as a bit having said first logic value is detected.

6. The method (30) of any of the previous claims, wherein the most significant bit of said binary sequence is associated to the first detection electric circuit (12, Te90) and the least significant bit of said binary sequence is associated to the last detection electric circuit (12, TeBP).

7. The method (30) of any of the previous claims, wherein said first logic value is a logic “1” and said second logic value is a logic “0”.

8. A system for predicting the remaining service life of a braking member of a vehicle, in terms of the remaining available mileage, based on monitoring the progression of wear and temperature of said braking member as result of vehicle use, wherein said system includes a detection unit (1 ) for monitoring successive wear levels and temperature of said braking member, wherein said detection unit (1 ) includes a detection sensor (2), an electric connector (3) configured to connect the detection unit (1 ) to an electronic control unit of the vehicle, and an electric wiring (4) configured toconnect the detection sensor (2) to the electric connector (3); wherein the detection sensor (2) comprises:- a body (5) having a longitudinal axis (6) and configured to be inserted into the braking member; and- a set of detection electric circuits (12) arranged in said body (5) in an ordered sequence along said longitudinal axis (6), said detection electric circuits (12) having respective first terminals (13) all electrically coupled to a conductive track (14) arranged in said body (5) of the detection sensor (2) and configured to receive a first power supply voltage (V-), and respective second terminals (15) electrically isolated amongst each other and configured to receive a second power supply voltage (V+), wherein each of said detection electric circuits (12) comprises a respective wear detector (16) of said braking member, and each of said detection electric circuits (12) in a subset of said detection electric circuits (12) comprises a respective temperature detector (17; Te90, Te50, Te10, TeBP) of said braking member, wherein a first detection electric circuit (12, Te90) of said ordered sequence is arranged toward a rubbing surface (7) of said braking member and a last detection electric circuit (12, TeBP) of said ordered sequence is arranged toward a support back plate of said braking member; and wherein the electric connector (3) comprises a microprocessor (180) coupled to said detection electric circuits (12) to sense their respective resistance values and a transceiver (182) coupled to said microprocessor (180), and configured to transmit a message indicative of the wear degree and temperature of said braking member to an electronic control unit of said vehicle, said microprocessor being configured for: a) detecting (302) resistance values of a set of detection electric circuits (12) arranged in ordered sequence along an axis (6) of a detection sensor (2), wherein each of said detection electric circuits (12) comprises a respective wear detector (16) of the braking member, and each detection electric circuit (12) in a subset of said detection electric circuits (12) comprises a respective temperature detector (17; Te90, Te50, Te10, TeBP) of the braking member, wherein a first detection electric circuit (12, Te90) of said ordered sequence is arranged toward a rubbing surface (7) of said braking member and a last detection electric circuit (12, TeBP) of saidordered sequence is arranged toward a support back plate of said braking member; b) producing (302) a N-bit binary sequence, N being the number of said detection electric circuits (12), wherein the bits of said binary sequence are orderly associated, from a most significant bit to a least significant bit, to said ordered sequence of detection electric circuits (12), and wherein each bit of said binary sequence takes a first logic value if the corresponding detection electric circuit (12) is electrically continuous and a second logic value if the corresponding detection electric circuit (12) is electrically interrupted; c) identifying (304), in said N-bit binary sequence, a most significant bit amongst the bits having said first logic value, and determining the wear degree of said braking member as a function of the position of said identified bit in said binary sequence; d) identifying (306), in a subset of said N-bit binary sequence corresponding to said subset of detection electric circuits (12), a further most significant bit amongst the bits having said first logic value, and determining the temperature of said braking member as a function of the resistance of the temperature detector associated to the detection electric circuit (12) corresponding to said further most significant bit; e) storing (300) a set of allowable cases for said N-bit binary sequence; f) comparing (308) said N-bit binary sequence to said stored allowable cases; and g) producing (308) an error message if said N-bit binary sequence does not correspond to any of said stored allowable cases, the electronic control unit of the vehicle being also configured for:- associating the interruption of a given detection electric circuit (12) to a corresponding value of a dimension of the braking member which is subject to decrease due to wear- detecting the vehicle mileage at the installation of the braking member and at each subsequent detection of a given level of wear of the braking member corresponding to the interruption of a given detection electric circuit (12),- storing the different mileages so detected and the correspondingvalues of said dimension of the braking member,- in such a way that after each detection of a given level of wear of the braking member, the stored data on the detected mileages and corresponding values of said dimension of the braking member can be used to estimate the remaining service life of the braking member in terms of remaining mileage available before a predetermined minimum value of said dimension of the braking member is reached.

9. The system of claim 8, wherein said set of detection electric circuits (12) comprises:- a first circuit (12), comprising a respective wear detector (16) and a respective resistance thermometer (Te90), arranged at 90% of the usable thickness of said braking member;- a second circuit (12), comprising a respective wear detector (16), arranged at 70% of the usable thickness of said braking member;- a third circuit (12), comprising a respective wear detector (16) and a respective resistance thermometer (Te50), arranged at 50% of the usable thickness of said braking member;- a fourth circuit (12), comprising a respective wear detector (16), arranged at 30% of the usable thickness of said braking member;- a fifth circuit (12), comprising a respective wear detector (16) and a respective resistance thermometer (Te10), arranged at 10% of the usable thickness of said braking member;- a sixth circuit (12), comprising a respective wear detector (16), arranged at 0% of the usable thickness of said braking member;- a seventh circuit (12), comprising a respective wear detector (16), arranged between 0% of the usable thickness of said braking member and a support back plate of said braking member; and- an eighth circuit (12), comprising a respective wear detector (16) and a respective resistance thermometer (TeBP), arranged at said support back plate of said braking member.

10. A computer program product loadable in a memory of at least one processing device, and comprising software code instructions which, when the program is executed by said at least one processing device, cause said at least one processing device to carry out the method of any of claims 1 to 7.

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