A delay line type SAW-based connecting rod bearing temperature measurement system and method

Abstract

The application relates to a connecting rod bearing temperature measuring system and method based on a delay line type SAW, which comprises a radio frequency signal controller, a coaxial cable, a delay line type SAW sensor and a signal transceiving antenna; the radio frequency signal controller is electrically connected with the coaxial cable, and the coaxial cable is electrically connected with the signal transceiving antenna; wherein the radio frequency signal controller is used for generating a radio frequency signal and analyzing a connecting rod bearing temperature signal according to a return signal; the coaxial cable is used for transmitting the radio frequency signal and the return signal; the signal transceiving antenna is used for sending the radio frequency signal to the delay line type SAW sensor and receiving a return signal of the delay line type SAW sensor; and the delay line type SAW sensor is used for collecting a temperature signal and modulating the temperature signal into the radio frequency signal to obtain the return signal. The application provides the connecting rod bearing temperature measuring system and method based on the delay line type SAW, improves the temperature measuring range and precision, shortens the measuring time, and avoids the interference between sensor signals.

Description

Technical Field

[0001] This invention relates to the field of engine temperature measurement technology, and in particular to a connecting rod bearing temperature measurement system and method based on delayed linear shape (SAW). Background Technology

[0002] High efficiency, reliability, long lifespan, and intelligence are the development directions of modern marine engines. The engine is the main propulsion unit and prime mover of a ship's generator set. Its connecting rod connects the piston and crankshaft, converting the reciprocating motion of the piston into the rotational motion of the crankshaft. The small end bushing (connecting rod bushing) matches the piston pin, and the large end bushing matches the crankshaft main journal. The bushings operate in a harsh environment, bearing the gas forces generated by combustion in the cylinder and alternating loads. Excessive wear of the bushings can cause damage, ranging from minor bushing failure to severe deformation and breakage of the connecting rod or even the crankshaft, seriously affecting the engine's reliability and safety. Monitoring the wear condition of the connecting rod bushings is one of the main aspects of engine intelligence.

[0003] To achieve accurate measurement of bearing temperature, existing wireless passive temperature measurement systems for connecting rod bearings are primarily developed based on resonant surface acoustic wave (SAW) wireless passive temperature sensors. The resonant SAW sensor receives a wirelessly transmitted swept frequency signal, converts it into a surface acoustic wave via an interdigital transducer, and forms a standing wave within the resonant cavity. The SAW travels on the surface of the resonant SAW element substrate and is reflected by a reflective grating. When the external swept frequency signal stops, the interdigital transducer converts the SAW within the resonant cavity into an echo electrical signal. When the frequency of the external swept frequency signal matches the resonant frequency of the resonant cavity within the resonant SAW element, resonance occurs within the resonator, resulting in the strongest reflected echo signal. This echo signal can be received to measure the resonant frequency of the SAW element. Furthermore, the resonant frequency of the resonant cavity has a linear relationship with temperature, allowing for temperature measurement. The resonant SAW wireless passive temperature sensor communicates wirelessly, requires no power supply, is relatively small, has a stable internal structure, and can be directly mounted by drilling to contact the surface of the measured component (bearing).

[0004] However, the wireless passive temperature measurement system for connecting rod bearings based on resonant SAW sensors requires the transmission of frequency sweep signals to measure temperature. The frequency sweep time is limited by the range of the scanning frequency band, the accuracy of the scanning frequency, and the hardware response time. In order to achieve a wider temperature range and higher accuracy temperature measurement, the frequency sweep time needs to be increased, which greatly increases the temperature measurement time. The echo signal of the resonant SAW element is relatively strong. In order to avoid frequency band interference between the signals of the sensors of different connecting rod bearings in the engine, a frequency division multiple access method needs to be adopted. That is, each connecting rod bearing in the same engine needs to be equipped with a resonant SAW temperature sensor with a different resonant frequency, which increases the measurement cost. Summary of the Invention

[0005] In view of this, it is necessary to provide a connecting rod bearing temperature measurement system and method based on delayed linear SAW, so as to solve the problem that the temperature measurement time, temperature measurement range and measurement accuracy of the existing connecting rod bearing temperature measurement system cannot be simultaneously achieved, and the measurement cost will be increased in order to reduce the interference between sensor signals.

[0006] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution:

[0007] In a first aspect, the present invention provides a connecting rod bearing temperature measurement system based on a delayed linear SAW sensor, comprising: a radio frequency signal controller, a coaxial cable, a delayed linear SAW sensor, and a signal transceiver antenna; the radio frequency signal controller is electrically connected to the coaxial cable, and the coaxial cable is electrically connected to the signal transceiver antenna.

[0008] Among them, the radio frequency signal controller is used to generate radio frequency signals and analyze the temperature signal of the connecting rod bearing based on the echo signal;

[0009] Coaxial cable is used to transmit radio frequency signals and echo signals;

[0010] The signal transceiver antenna is used to send radio frequency signals to the delayed linear SAW sensor and receive the echo signals from the delayed linear SAW sensor.

[0011] The delayed linear SAW sensor is used to acquire temperature signals and modulate them into an radio frequency signal to obtain an echo signal.

[0012] Preferably, the radio frequency signal controller includes: a main controller, a radio frequency signal circuit, and an echo signal circuit; the main controller is electrically connected to the radio frequency signal circuit and the echo signal circuit respectively, and the radio frequency signal circuit and the echo signal circuit are electrically connected to a coaxial cable respectively;

[0013] The main controller is used to generate an initial signal, acquire echo signals, and analyze the temperature signal of the connecting rod bearing based on the echo signals.

[0014] Radio frequency (RF) signal circuitry is used to process the initial signal to obtain an RF signal and then transmit the RF signal.

[0015] The echo signal circuit is used to acquire echo signals, preprocess the echo signals, and send them to the main controller.

[0016] Preferably, the radio frequency signal circuit includes: a frequency multiplier, a power divider, a gain amplifier, and a first bandpass filter; the frequency multiplier, the power divider, the gain amplifier, and the first bandpass filter are electrically connected in sequence;

[0017] Among them, the frequency multiplier is used to multiply the initial signal to obtain a high-frequency signal, and then send the high-frequency signal to the power divider.

[0018] A power divider is used to split a high-frequency signal into two output signals with equal energy, and then send the output signals to the gain amplifier and the echo signal circuit respectively.

[0019] A gain amplifier is used to amplify the output signal and send the amplified output signal to the first bandpass filter.

[0020] The first bandpass filter is used to denoise the amplified output signal to obtain the radio frequency signal.

[0021] Preferably, the echo signal circuit includes: a second bandpass filter, a low-noise amplifier, an IQ demodulator, and an AD acquisition board; the second bandpass filter, the low-noise amplifier, the IQ demodulator, and the AD acquisition board are electrically connected in sequence.

[0022] The second bandpass filter is used to denoise the echo signal and send the denoised echo signal to the low-noise amplifier.

[0023] The low-noise amplifier is used to amplify the denoised echo signal and send the amplified echo signal to the IQ demodulator.

[0024] The IQ demodulator is used to compare the output signal with the amplified echo signal to obtain an analog signal, and then send the analog signal to the AD acquisition board.

[0025] AD acquisition board is used to convert analog signals into digital signals and send the digital signals to the main controller.

[0026] Preferably, the radio frequency signal controller further includes: a radio frequency switch and a circulator; the radio frequency switch is electrically connected to the first bandpass filter, the second bandpass filter, the main controller and the circulator respectively;

[0027] Among them, the radio frequency switch receives the control signal sent by the main controller, intercepts the radio frequency signal, sends the intercepted radio frequency signal to the circulator, and switches the transmit channel to the receive channel;

[0028] A circulator is used to isolate radio frequency signals and echo signals.

[0029] Preferably, it further includes: an engine block, a support bracket, and a connecting rod bearing; wherein, the radio frequency signal controller is fixed to the outer side of the engine block; the support bracket is fixedly connected to the engine block, and the signal transceiver antenna is fixed to the support bracket; the delay linear SAW sensor is fixed to the connecting rod bearing.

[0030] Preferably, the signal transceiver antenna is a PCB antenna, which is fixed to the support bracket.

[0031] Preferably, the delayed linear SAW sensor includes: an interdigital transducer, a substrate material, and a reflective grating; the interdigital transducer and the reflective grating are respectively fixed to the substrate material;

[0032] Among them, the interdigital transducer is used to convert radio frequency signals into surface acoustic waves and to convert reflected surface acoustic waves into echo signals.

[0033] The substrate material is used to fix the interdigital transducer and the reflective grating, and deforms with temperature changes;

[0034] A reflective grating is used to reflect surface acoustic waves that detect deformation of the substrate material.

[0035] Preferably, the delayed linear SAW sensor further includes a sensor antenna; the sensor antenna is used to receive the radio frequency signal transmitted by the signal transceiver antenna and send the echo signal to the signal transceiver antenna.

[0036] Secondly, the present invention also provides a method for measuring the temperature of a connecting rod bearing based on a delayed linear SAW (Short-Wave Arrangement), comprising: a connecting rod bearing temperature measurement system based on a delayed linear SAW as described in any of the above implementations; and a method for measuring the temperature of a connecting rod bearing based on a delayed linear SAW.

[0037] Radio frequency (RF) signals are generated by an RF signal controller and transmitted to a delayed linear SAW sensor via a coaxial cable and a signal transceiver antenna.

[0038] The delayed linear SAW sensor acquires the temperature signal and modulates the temperature signal onto the radio frequency signal to obtain the echo signal;

[0039] The echo signal is transmitted to the radio frequency signal controller via a coaxial cable and a signal transceiver antenna.

[0040] The radio frequency signal controller analyzes and demodulates the echo signal to obtain the temperature signal.

[0041] The beneficial effects of the above embodiments are as follows: This invention relates to a connecting rod bearing temperature measurement system and method based on a delayed linear SAW sensor. The system includes: a radio frequency (RF) signal controller, a coaxial cable, a delayed linear SAW sensor, and a signal transceiver antenna. The RF signal controller is electrically connected to the coaxial cable, and the coaxial cable is electrically connected to the signal transceiver antenna. The RF signal controller generates an RF signal and analyzes the temperature signal of the connecting rod bearing based on the echo signal. The coaxial cable transmits the RF signal and the echo signal. The signal transceiver antenna transmits the RF signal to the delayed linear SAW sensor and receives the echo signal from the delayed linear SAW sensor. The delayed linear SAW sensor acquires the temperature signal and modulates it into the RF signal to obtain the echo signal. This invention provides a connecting rod bearing temperature measurement system and method based on a delayed linear SAW sensor. By measuring the temperature of the engine's connecting rod bearing using a delayed linear SAW sensor, frequency sweeping is not required, shortening the transmission and reception time of the RF signal, improving the range and accuracy of temperature measurement, reducing measurement time, and avoiding interference between sensor signals. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of an embodiment of the connecting rod bearing temperature measurement system based on delayed linear SAW provided by the present invention;

[0043] Figure 2 A schematic diagram of an embodiment of the radio frequency signal controller provided by the present invention;

[0044] Figure 3 A schematic diagram of a structure of an embodiment of the delay-line SAW sensor provided by the present invention;

[0045] Figure 4 This is a schematic flowchart of an embodiment of the connecting rod bearing temperature measurement method based on delayed linear SAW provided by the present invention. Detailed Implementation

[0046] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which form part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0047] In the description of this application, "multiple" means two or more, unless otherwise expressly and specifically defined.

[0048] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0049] This invention provides a connecting rod bearing temperature measurement system and method based on delayed linear SAW (Sequentially Delayed Wheat Surface) profiles, which will be described below.

[0050] Please see Figure 1 , Figure 1 This is a schematic diagram of an embodiment of the connecting rod bearing temperature measurement system based on delayed linear SAW provided by the present invention. A specific embodiment of the present invention discloses a connecting rod bearing temperature measurement system based on delayed linear SAW, comprising: a radio frequency signal controller 110, a coaxial cable 120, a delayed linear SAW sensor 130, and a signal transceiver antenna 140; the radio frequency signal controller 110 is electrically connected to the coaxial cable 120, and the coaxial cable 120 is electrically connected to the signal transceiver antenna 140;

[0051] Among them, the radio frequency signal controller 110 is used to generate radio frequency signals and analyze the temperature signal of the connecting rod bearing 170 based on the echo signal;

[0052] Coaxial cable 120, used for transmitting radio frequency signals and echo signals;

[0053] The signal transceiver antenna 140 is used to send radio frequency signals to the delayed linear SAW sensor 130 and receive the echo signals from the delayed linear SAW sensor 130.

[0054] The delayed linear SAW sensor 130 is used to acquire temperature signals and modulate the temperature signals into radio frequency signals to obtain echo signals.

[0055] In the above embodiment, the radio frequency signal controller 110 is an integrated device that can generate radio frequency signals, send out radio frequency signals, receive returned echo signals, and analyze the echoes to detect the temperature signal of the connecting rod bearing 170, thereby realizing the temperature detection of the connecting rod bearing 170.

[0056] Coaxial cable (120) is a type of wire and signal transmission line suitable for a wide variety of applications, most notably television broadcasting, long-distance telephone transmission, short-distance connections between computer systems, and local area networks. It can be used for the transmission of both analog and digital signals.

[0057] It should be noted that the RF signal controller based on the resonant SAW temperature sensor requires an envelope detector, which determines the resonant frequency by measuring the envelope amplitude of the echo signal at different frequency points; the RF signal controller 110 based on the delay line SAW sensor 130 performs orthogonal phase detection and frequency conversion of the echo signal through an IQ demodulator in order to detect the phase.

[0058] Compared with the prior art, this embodiment provides a connecting rod bearing temperature measurement system based on a delayed linear SAW sensor, including: a radio frequency (RF) signal controller 110, a coaxial cable 120, a delayed linear SAW sensor 130, and a signal transceiver antenna 140; the RF signal controller 110 is electrically connected to the coaxial cable 120, and the coaxial cable 120 is electrically connected to the signal transceiver antenna 140; wherein, the RF signal controller 110 is used to generate RF signals and analyze the temperature signal of the connecting rod bearing 170 based on the echo signal; the coaxial cable 120 is used to transmit the RF signal and the echo signal; the signal transceiver antenna 140 is used to send the RF signal to the delayed linear SAW sensor 130 and receive the echo signal from the delayed linear SAW sensor 130; the delayed linear SAW sensor 130 is used to acquire the temperature signal and modulate the temperature signal into the RF signal to obtain the echo signal. The present invention provides a connecting rod bearing temperature measurement system and method based on delayed linear SAW sensor. The system measures the temperature of the connecting rod bearing 170 of the engine by means of a delayed linear SAW sensor 130. It does not require frequency sweeping, shortens the transmission and reception time of radio frequency signals, improves the range and accuracy of temperature measurement, shortens the measurement time, and avoids interference between sensor signals.

[0059] Please see Figure 2 , Figure 2 This is a schematic diagram of an embodiment of the radio frequency signal controller provided by the present invention. In some embodiments of the present invention, the radio frequency signal controller 110 includes: a main controller 210, a radio frequency signal circuit 220, and an echo signal circuit 230; the main controller 210 is electrically connected to the radio frequency signal circuit 220 and the echo signal circuit 230 respectively, and the radio frequency signal circuit 220 and the echo signal circuit 230 are electrically connected to the coaxial cable 120 respectively.

[0060] The main controller 210 is used to generate an initial signal, acquire echo signals, and analyze the temperature signal of the connecting rod bearing 170 based on the echo signals.

[0061] The radio frequency signal circuit 220 is used to process the initial signal to obtain the radio frequency signal and transmit the radio frequency signal;

[0062] The echo signal circuit 230 is used to acquire echo signals, preprocess the echo signals, and send them to the main controller 210.

[0063] In the above embodiments, besides generating the initial signal, the main controller 210 primarily analyzes and processes the acquired echo signals to calculate the real-time temperature of the connecting rod bearing 170. As a preferred embodiment, the main controller 210 can be developed based on a parallel processing processor such as an FPGA. It is understood that the main controller 210 can also be selected in other forms, as long as it can calculate the real-time temperature of the connecting rod bearing 170; this invention does not impose further limitations in this regard.

[0064] The radio frequency signal circuit 220 can amplify, distribute and denoise the initial signal to obtain a radio frequency signal that meets the acquisition requirements. The radio frequency signal is then sent to the signal transceiver antenna 140 to acquire the temperature of the connecting rod bearing 170.

[0065] The echo signal circuit 230 receives the echo signal after the temperature of the connecting rod bearing 170 is collected by the delayed linear SAW sensor 130, performs noise reduction, amplification and demodulation processing on the echo signal, and converts the echo signal into a digital signal before sending it to the main controller 210, which then analyzes and calculates it.

[0066] In some embodiments of the present invention, the radio frequency signal circuit 220 includes: a frequency multiplier 221, a power divider 222, a gain amplifier 223, and a first bandpass filter 224; the frequency multiplier 221, the power divider 222, the gain amplifier 223, and the first bandpass filter 224 are electrically connected in sequence.

[0067] Among them, the frequency multiplier 221 is used to multiply the initial signal to obtain a high-frequency signal, and then send the high-frequency signal to the power divider 222;

[0068] The power divider 222 is used to split the high-frequency signal into two output signals with equal energy, and send the output signals to the gain amplifier 223 and the echo signal circuit 230 respectively.

[0069] Gain amplifier 223 is used to amplify the output signal and send the amplified output signal to the first bandpass filter 224;

[0070] The first bandpass filter 224 is used to denoise the amplified output signal to obtain the radio frequency signal.

[0071] In the above embodiment, the frequency multiplier 221 amplifies the initial signal generated by the main controller 210 to generate a high-frequency signal, so as to excite the delay linear SAW sensor 130 in the sensor body.

[0072] The power divider 222 splits a high-frequency signal into two output signals with equal energy. One of them enters the IQ demodulator 233 as the local oscillator signal, and the other enters the gain amplifier 223.

[0073] Gain amplifier 223 further amplifies the output signal, thereby improving the detectability of the output signal and acquiring the temperature signal.

[0074] The first bandpass filter 224 filters out frequency components other than the frequency of the amplified output signal, eliminating interference from external noise in practical engineering applications and improving detection accuracy.

[0075] In some embodiments of the present invention, the echo signal circuit 230 includes: a second bandpass filter 231, a low-noise amplifier 232, an IQ demodulator 233, and an AD acquisition board 234; the second bandpass filter 231, the low-noise amplifier 232, the IQ demodulator 233, and the AD acquisition board 234 are electrically connected in sequence.

[0076] The second bandpass filter 231 is used to denoise the echo signal and send the denoised echo signal to the low-noise amplifier 232.

[0077] The low-noise amplifier 232 is used to amplify the denoised echo signal and send the amplified echo signal to the IQ demodulator 233.

[0078] The IQ demodulator 233 is used to compare the output signal with the amplified echo signal to obtain an analog signal, and then send the analog signal to the AD acquisition board 234.

[0079] AD acquisition board 234 is used to convert analog signals into digital signals and send the digital signals to the main controller 210.

[0080] In the above embodiment, the second bandpass filter circuit filters the echo signal emitted by the delayed linear SAW sensor 130 to remove interference noise during the signal echo process.

[0081] The low-noise amplifier 232 amplifies the weak echo signal for subsequent signal analysis and processing.

[0082] The IQ demodulator 233 further performs quadrature phase detection and frequency conversion on the amplified echo signal, converting the echo signal into a baseband signal (i.e., an analog signal).

[0083] The AD acquisition board 234 converts analog signals into digital signals so that the main controller 210 can analyze and process the echo signals.

[0084] In some embodiments of the present invention, the radio frequency signal controller 110 further includes: a radio frequency switch 240 and a circulator 250; the radio frequency switch 240 is electrically connected to a first bandpass filter 224, a second bandpass filter 231, a main controller 210 and a circulator 250 respectively;

[0085] Among them, the radio frequency switch 240 receives the control signal sent by the main controller 210, intercepts the radio frequency signal, sends the intercepted radio frequency signal to the circulator 250, and switches the transmit channel to the receive channel.

[0086] Circulator 250 is used to isolate radio frequency signals and echo signals.

[0087] In the above embodiment, the main controller 210 also generates a control signal (TTL signal). The TTL signal generated by the main controller 210 is directly transmitted to the radio frequency switch 240. The radio frequency switch 240 intercepts the radio frequency signal for a certain period of time based on the TTL signal and excites the SAW element of the sensor body through the signal transceiver antenna 140. After the signal is excited, the radio frequency switch 240 converts the signal transmission channel into a receiving channel. The circulator 250 can effectively isolate the transmitted signal and the received signal by relying on its unidirectional ring transmission characteristics.

[0088] In some embodiments of the present invention, the system further includes: an engine block 150, a support bracket 160, and a connecting rod bearing 170; wherein, a radio frequency signal controller 110 is fixed to the outer side of the engine block 150; the support bracket 160 is fixedly connected to the engine block 150, and a signal transceiver antenna 140 is fixed to the support bracket 160; and a delay linear SAW sensor 130 is fixed to the connecting rod bearing 170.

[0089] In the above embodiments, the connecting rod bearing 170 temperature measurement system based on delayed linear SAW provided by the present invention acquires the temperature signal of the connecting rod bearing 170 by fixing the radio frequency signal controller 110 on the engine block 150 and transmitting the signal through a coaxial cable and a signal transceiver antenna 140 fixed on the support bracket 160.

[0090] In some embodiments of the present invention, the signal transceiver antenna 140 is a PCB antenna, and the PCB antenna is fixed to the support bracket 160.

[0091] In the above embodiments, the signal transceiver antenna 140 and the delayed linear SAW sensor 130 exchange information in a one-to-one manner, that is, one signal transceiver antenna 140 corresponds to one delayed linear SAW sensor 130. The signal transceiver antenna 140 should comprehensively consider transmission performance and size; therefore, this invention uses a PCB antenna to achieve performance matching that of a spring antenna in a smaller size, resulting in higher space utilization.

[0092] Please see Figure 3 , Figure 3This is a schematic diagram of a structure of an embodiment of the delay line SAW sensor provided by the present invention. In some embodiments of the present invention, the delay line SAW sensor 130 includes: an interdigital transducer 310, a substrate material 320, and a reflective grating 330; the interdigital transducer 310 and the reflective grating 330 are respectively fixed to the substrate material 320.

[0093] Among them, the interdigital transducer 310 is used to convert radio frequency signals into surface acoustic waves and to convert reflected surface acoustic waves into echo signals.

[0094] The substrate material 320 is used to fix the interdigital transducer 310 and the reflector grating 330, and deforms with temperature changes;

[0095] The reflective grating 330 is used to reflect surface acoustic waves that detect deformation of the substrate material 320.

[0096] In the above embodiment, the radio frequency signal is transmitted to the interdigital transducer 310, which converts the electrical signal (radio frequency signal) into a surface acoustic wave. The surface acoustic wave propagates on the substrate material 320. When it encounters the reflective grating 330 inside the sensor, it will be reflected back to the interdigital transducer 310 in sequence. The surface acoustic wave is converted into an electrical signal, which is an echo signal. The echo signal is sent to the radio frequency signal controller 110 for analysis and processing.

[0097] Unlike resonant SAW sensor designs, which employ a single reflective grating 330 on one side or one reflective grating 330 on each side, and primarily determine temperature by measuring the resonant frequency of the echo signal, the delay-line SAW sensor 130 typically arranges multiple reflective gratings 330 on one side to utilize the time delay / phase of the echo signal between the reflective gratings 330 for temperature measurement.

[0098] In some embodiments of the present invention, the delay linear SAW sensor 130 further includes a sensor antenna 340; the sensor antenna 340 is used to receive radio frequency signals transmitted by the signal transceiver antenna 140 and to send echo signals to the signal transceiver antenna 140.

[0099] In the above embodiments, the resonant frequencies of the delayed linear SAW sensor 130, sensor antenna 340, and signal transceiver antenna 140 should be consistent. Impedance matching should be performed between the delayed linear SAW sensor 130 and sensor antenna 340, and between the circuits of the RF signal controller 110, to reduce the loss of RF signals during transmission. The signals of the first bandpass filter 224 and the second bandpass filter 231 should be adjusted according to the resonant frequency. By reasonably adjusting the signal power, the optimal signal transmission and reception distance and angle between the signal transceiver antenna 140 and the sensor antenna 340 can be adjusted.

[0100] Please see Figure 4 , Figure 4 This is a flowchart illustrating an embodiment of the connecting rod bearing temperature measurement method based on delayed linear SAW provided by the present invention. In a second aspect, the present invention also provides a connecting rod bearing temperature measurement method based on delayed linear SAW, comprising a connecting rod bearing temperature measurement system based on delayed linear SAW as described in any of the above implementations, including:

[0101] S401: An RF signal is generated by an RF signal controller and transmitted to a delayed linear SAW sensor via a coaxial cable and a signal transceiver antenna.

[0102] The S402, a delayed linear SAW sensor, acquires temperature signals and modulates these signals onto an radio frequency signal to obtain an echo signal.

[0103] S403. The echo signal is transmitted to the radio frequency signal controller via a coaxial cable and a signal transceiver antenna.

[0104] S404, the radio frequency signal controller, analyzes and demodulates the echo signal to obtain the temperature signal.

[0105] In the above embodiment, the RF signal controller 110 generates an RF signal. The delayed linear SAW sensor 130, mounted on the connecting rod bearing 170, receives the RF signal transmitted by the signal transceiver antenna 140. After activating the delayed linear SAW sensor 130, an echo signal is generated. The echo signal is transmitted to the RF signal controller 110 through the signal transceiver antenna 140. After filtering and low-noise signal amplification, IQ demodulation is performed. In the IQ demodulator 233, the echo signal is split into two identical signals after passing through the 0° power divider 222, while the local oscillator signal generated by the RF signal is split into two signals with a 90° phase difference after passing through the 90° power divider 222. The signals are mixed, and the following relationship can be obtained:

[0106]

[0107]

[0108] A and B represent the signal amplitude, t is the period time extracted based on the TTL signal, specifically from the start time of one radio frequency signal transmission to the start time of the next radio frequency signal transmission, w0 is the angular frequency, and φ i The phase change of the echo signal from the i-th reflector grating 330 is represented by the following: After low-pass filtering, the high-frequency signals of I and Q are removed, resulting in two orthogonal signals I' and Q':

[0109]

[0110]

[0111] Two orthogonal signals I' and Q' are converted from analog to digital signals by the AD acquisition board 234 and sent to the main controller 210. In the main controller 210, periodic extraction is performed based on the TTL signal of the control RF switch 240. Since the connecting rod bearing 170 is in a rotating state, the signal is weak when the signal transceiver antenna 140 is far from the delay linear SAW sensor 130. Therefore, a threshold can be set to determine whether the number of sampling points n greater than the threshold in the periodic data is greater than the rated number of points n. 额定 When n is greater than n 额定 When n is within acceptable signal range, the signal transceiver antenna 140 and the delayed linear SAW sensor 130 can be considered to be within acceptable signal range, and the next step of calculation can be performed; when n is less than n 额定 At this time, the signal transmitted between the signal transceiver antenna 140 and the delayed linear SAW sensor 130 is weak and it is difficult to calculate the phase. The radio frequency signal can be regenerated to excite the delayed linear SAW sensor 130.

[0112] When n is greater than n 额定 At that time, the periodic data of the I and Q channels are used in the main controller 210 to calculate the phase φ through arctangent operation. i Changes:

[0113]

[0114] Furthermore, the phase φ is determined by the positive and negative signs of the I' and Q' signals. i The quadrant it is located in is shown in the following formula:

[0115]

[0116]

[0117]

[0118] Furthermore, the phase values ​​of different reflective gratings 330 of the delayed linear SAW sensor 130 are obtained, and the phase difference of the echo signals from different reflective gratings 330, such as φ1-φ2 ​​and φ2-φ3, is calculated by subtraction. During real-time calculation, the temperature values ​​t1 and t2 corresponding to φ1-φ2 ​​and φ2-φ3 are calculated respectively, and the accurate real-time temperature is calculated by averaging t1 and t2.

[0119]

[0120] The delayed linear SAW sensor 130 is placed in a constant temperature chamber. The phase difference value is calculated by adjusting the temperature to obtain an accurate temperature-phase difference curve. When the engine connecting rod bearing 170 is monitored in real time, the temperature corresponding to the phase difference value calculated in real time on the temperature-phase difference curve is the real-time temperature of the connecting rod bearing 170.

[0121] Existing resonant SAW sensors measure temperature based on frequency sweep signals. The hardware scan step time is typically 0.05s-0.1s. Assuming a scan step time of 0.05s, a temperature measurement range of 0°C-150°C for the resonant SAW sensor, and a measurement accuracy of 0.1°C, then the time during the frequency sweep process is:

[0122]

[0123] The connecting rod bearing temperature at 170°C is a slowly varying signal. Therefore, a frequency sweep can be performed using five frequencies above and below the frequency of the last measured temperature to reduce the sweep time. The optimized sweep time is:

[0124] T' 扫频 =0.05 × 11 = 0.55 s;

[0125] Using temperature measurement as a standard of once per revolution of the engine crankshaft, the highest speed at which a resonant SAW sensor can achieve temperature measurement is:

[0126]

[0127] This rotational speed is only applicable to the temperature measurement of the connecting rod bearing 170 of low-speed marine engines. For medium-speed and high-speed engines, its measurement efficiency will be reduced. Furthermore, the frequency division multiple access sensor design will make the RF signal generation and signal processing complexity of the resonant SAW wireless temperature measurement system higher than that of the delayed linear SAW wireless temperature measurement system.

[0128] The delayed linear SAW sensor 130 based on this invention requires only a fixed frequency radio frequency excitation signal. The excitation time depends on the distance between the reflector grating 330 and the interdigital transducer 310. Assuming the excitation time of the radio frequency signal is 250 ns, the excitation time of the radio frequency signal on the delayed linear SAW element is 4 μs, meaning the time period from one excitation to the next is 4 μs. The echo signal of the delayed linear SAW sensor 130 is relatively weak; therefore, the signal transceiver antenna 140 and the sensor antenna 340 should be as close as possible. Assuming the angle between the signal transceiver antenna 140 and the sensor antenna 340 within the acceptable signal range during the movement of the connecting rod bearing 170 is 20°, the starting point of the excitation time period is not necessarily located at the starting point of the optimal acceptable signal angle range. Therefore, a certain time margin should be allowed during measurement. Assuming there should be an 8 μs excitation time within the 20° acceptable signal angle, the highest rotational speed that the delayed linear SAW sensor 130 can achieve to meet the temperature measurement standard is:

[0129]

[0130] The above is a single-factor influence analysis. When the signal generation time, coaxial cable 120 transmission time, and processing time are the same, the delayed linear SAW sensor 130 should have a faster temperature measurement response time than the resonant SAW sensor, and is suitable for low-speed, medium-speed, and high-speed engines.

[0131] In summary, this invention relates to a connecting rod bearing temperature measurement system and method based on a delayed linear SAW sensor. The system includes: a radio frequency (RF) signal controller 110, a coaxial cable 120, a delayed linear SAW sensor 130, and a signal transceiver antenna 140. The RF signal controller 110 is electrically connected to the coaxial cable 120, and the coaxial cable 120 is electrically connected to the signal transceiver antenna 140. The RF signal controller 110 generates an RF signal and analyzes the temperature signal of the connecting rod bearing 170 based on the echo signal. The coaxial cable 120 transmits the RF signal and the echo signal. The signal transceiver antenna 140 transmits the RF signal to the delayed linear SAW sensor 130 and receives the echo signal from the delayed linear SAW sensor 130. The delayed linear SAW sensor 130 acquires the temperature signal and modulates it into the RF signal to obtain the echo signal. The present invention provides a connecting rod bearing temperature measurement system and method based on delayed linear SAW sensor. The system measures the temperature of the connecting rod bearing 170 of the engine by means of a delayed linear SAW sensor 130. It does not require frequency sweeping, shortens the transmission and reception time of radio frequency signals, improves the range and accuracy of temperature measurement, shortens the measurement time, and avoids interference between sensor signals.

[0132] The serial numbers assigned to components in this document, such as "first" and "second," are used solely to distinguish the described objects and do not have any sequential or technical meaning. In the description of this application, it should be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used solely for the convenience of describing this application and for simplification, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0133] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A delay line SAW based connecting rod bearing temperature measurement system, characterized by, The application relates to a radio frequency signal controller, a coaxial cable, a delay line type SAW sensor and a signal transceiving antenna; the radio frequency signal controller is electrically connected with the coaxial cable, and the coaxial cable is electrically connected with the signal transceiving antenna. The radio frequency signal controller is used for generating a radio frequency signal and analyzing a temperature signal of a connecting rod bearing bush according to a return signal. The coaxial cable is used for transmitting the radio frequency signal and the return signal. The signal transceiving antenna is used for transmitting the radio frequency signal to the delay line type SAW sensor and receiving a return signal of the delay line type SAW sensor. The delay line type SAW sensor is used for collecting a temperature signal and modulating the temperature signal into the radio frequency signal to obtain the return signal. The radio frequency signal controller comprises a main controller, a radio frequency signal circuit and a return signal circuit; the main controller is electrically connected with the radio frequency signal circuit and the return signal circuit respectively, and the radio frequency signal circuit and the return signal circuit are electrically connected with the coaxial cable respectively. The main controller is used for generating an initial signal, collecting a return signal and analyzing a temperature signal of a connecting rod bearing bush according to the return signal. The radio frequency signal circuit is used for processing the initial signal to obtain a radio frequency signal and transmitting the radio frequency signal. The return signal circuit is used for collecting a return signal, pre-processing the return signal and transmitting the return signal to the main controller. The radio frequency signal circuit comprises a frequency multiplier, a power divider, a gain amplifier and a first band pass filter; the frequency multiplier, the power divider, the gain amplifier and the first band pass filter are electrically connected in sequence. The frequency multiplier is used for frequency multiplying the initial signal to obtain a high frequency signal and transmitting the high frequency signal to the power divider. The power divider is used for dividing the high frequency signal into two output signals with equal energy and transmitting the output signals to the gain amplifier and the return signal circuit respectively. The gain amplifier is used for amplifying the output signals and transmitting the amplified output signals to the first band pass filter. The first band pass filter is used for denoising the amplified output signals to obtain a radio frequency signal. The return signal circuit comprises a second band pass filter, a low noise amplifier, an IQ demodulator and an AD acquisition board; the second band pass filter, the low noise amplifier, the IQ demodulator and the AD acquisition board are electrically connected in sequence.

2. The delay line SAW based connecting rod bearing temperature measurement system of claim 1, wherein, The second band pass filter is used for denoising the return signal and transmitting the denoised return signal to the low noise amplifier. The low noise amplifier is used for amplifying the denoised return signal and transmitting the amplified return signal to the IQ demodulator. The IQ demodulator is used for comparing the output signal and the amplified return signal to obtain an analog signal and transmitting the analog signal to the AD acquisition board. The AD acquisition board is used for converting the analog signal into a digital signal and transmitting the digital signal to the main controller. ​ 3. The delay line SAW based connecting rod bearing temperature measurement system of claim 2, wherein, The radio frequency signal controller further comprises a radio frequency switch and a circulator; the radio frequency switch is electrically connected with the first band-pass filter, the second band-pass filter, the main controller and the circulator respectively; The radio frequency switch receives a control signal sent by the main controller, intercepts the radio frequency signal, sends the intercepted radio frequency signal to the circulator, and switches the transmitting channel to a receiving channel; The circulator is used for isolating the radio frequency signal and the echo signal.

4. The delay line SAW-based connecting rod bearing temperature measurement system of claim 1, wherein, Further comprising: An engine body, a support bracket and a connecting rod bearing; wherein the radio frequency signal controller is fixed to the outer side of the engine body; the support bracket is fixedly connected with the engine body, and the signal transceiving antenna is fixed to the support bracket; and the delay line type SAW sensor is fixed to the connecting rod bearing.

5. The delay line SAW based connecting rod bearing temperature measurement system of claim 4, wherein, The signal transceiving antenna is a PCB antenna, and the PCB antenna is fixed to the support bracket.

6. The delay line SAW based connecting rod bearing temperature measurement system of claim 1, wherein, The delay line type SAW sensor comprises an interdigital transducer, a base material and a reflection grating; the interdigital transducer and the reflection grating are fixed to the base material respectively; The interdigital transducer is used for converting the radio frequency signal into a surface acoustic wave and converting the reflected surface acoustic wave into an echo signal; The base material is used for fixing the interdigital transducer and the reflection grating and deforming with temperature change; The reflection grating is used for reflecting the surface acoustic wave detected by the deformation of the base material.

7. The delay line SAW based connecting rod bearing temperature measurement system of claim 6, wherein, The delay line type SAW sensor further comprises a sensor antenna; the sensor antenna is used for receiving the radio frequency signal sent by the signal transceiving antenna and sending the echo signal to the signal transceiving antenna.

8. A delay line SAW based connecting rod bearing temperature measurement method based on the delay line SAW based connecting rod bearing temperature measurement system according to any one of claims 1 to 7, characterized in that, Comprising: The radio frequency signal controller generates a radio frequency signal, and the radio frequency signal is sent to the delay line type SAW sensor through the coaxial cable and the signal transceiving antenna; The delay line type SAW sensor collects a temperature signal, modulates the temperature signal to the radio frequency signal to obtain an echo signal; The echo signal is sent to the radio frequency signal controller through the coaxial cable and the signal transceiving antenna; The radio frequency signal controller analyzes and demodulates the echo signal to obtain the temperature signal.

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