Diesel engine operation signal simulation system and simulation method

Abstract

The present application provides a diesel engine operation signal simulation system and simulation method, wherein the system comprises: a thermal resistance module for continuously simulating the signal of a PT100 thermal resistance temperature sensor; a current signal module for continuously simulating the signal of a 4-20mA current type sensor; a rotating speed signal module for continuously simulating the signal of a frequency type rotating speed signal digital switch dry joint; and a high frequency vibration signal module for continuously simulating the signal of a high frequency vibration signal. The present application realizes the simulation of various types of diesel engine operation signals, effectively reduces or replaces the actual vehicle operation of the diesel engine; adopts a modular and hierarchical design idea, which can not only reduce the volume, but also reduce the processing burden of the main control system, and is also convenient for heat dissipation and maintenance.

Description

Technical Field

[0001] This invention relates to the field of diesel engine signal simulation system technology, and more specifically, to a diesel engine operating signal simulation system and simulation method. Background Technology

[0002] In the development of diesel engine operation status monitoring and fault diagnosis systems, actual vehicle operation of the diesel engine is generally required when the system's hardware and software are involved in testing, debugging, experimentation, improvement, and acceptance. For large diesel engines, operation consumes a significant amount of fuel, water, and electricity; calculations show that the hourly operating cost is approximately 40,000 to 80,000 yuan. In addition, there are substantial subsequent maintenance costs. This operating method increases enterprise costs and inevitably leads to energy waste.

[0003] Meanwhile, during the development of the diesel engine operating status monitoring and fault diagnosis system, it is also necessary to simulate diesel engine faults in order to verify the accuracy and reliability of the monitoring and fault diagnosis system. This is something that is difficult to achieve even in actual vehicle operation. Summary of the Invention

[0004] To address the aforementioned shortcomings in the prior art, this invention provides a diesel engine operating signal simulation system and method.

[0005] According to one aspect of the present invention, a diesel engine operating signal simulation system is provided, comprising:

[0006] Thermocouple module, which is used to continuously output the signal of PT100 thermocouple temperature sensor in analog mode;

[0007] Current signal module, which is used to continuously simulate and output signals from a 4-20mA current-type sensor;

[0008] Speed ​​signal module, which is used to continuously analog output frequency-type speed signal digital switch dry contact signal;

[0009] High-frequency vibration signal module, which is used to continuously simulate and output high-frequency vibration signals.

[0010] Preferably, the RTD module includes several groups of RTD simulation units; wherein each group of RTD simulation units includes: an input operational amplifier U1, a D / A converter U4, an inverter U2, an output operational amplifier U3, and a standard resistor R. x ;in:

[0011] The input operational amplifier U1 is connected as a resistor follower, and its output voltage is U. iThe reference voltage of the D / A converter U4 is used as the reference voltage; the D / A converter U4 proportionally adjusts the reference voltage to obtain an output voltage U. D / A =K ui , where K ui The value of U4 after proportional adjustment of the reference voltage; when the inverter U2 operates in linear amplification mode, the potentials at both input terminals are equal, then the voltage at the inverting terminal of the inverter U2 is K. ui ; This is how the force applied to the standard resistor R is obtained. x The voltage on is U i =UK ui Where U is the total external input voltage applied to the standard resistor R. x The current on is I i =(UK) ui ) / R, where R is the equivalent combined resistance of the PT100 resistance temperature sensor; the output operational amplifier U3 is used to increase the amplitude of the signal;

[0012] The input operational amplifier U1, D / A converter U4, inverter U2, output operational amplifier U3, and standard resistor R are used. x The simulated equivalent combined resistance R of the PT100 RTD temperature sensor is:

[0013] R = U i / I i =R x / (1+K) (1)

[0014] Among them, U i I is the output voltage of the input operational amplifier U1; i Let R be the current flowing through the combined resistor R. x is the standard resistor; K is the control coefficient, which is adjusted by changing the input digital value of the D / A converter U4.

[0015] Preferably, the current signal module includes several groups of current signal simulation units, wherein each group of current signal simulation units includes: a signal amplification chip, a transistor, and a resistor R. in The signal amplification chip controls the transistor to operate in the amplification region, and the resistor R in Connected in series between the pins of the transistor and the signal amplifier chip, the resistor R is detected. in The voltage is used to feedback and adjust the input of the transistor, thereby realizing the analog output of the current signal.

[0016] Preferably, the rotational speed signal module includes at least one set of rotational speed signal simulation units; wherein each set of rotational speed signal simulation units includes: a pulse width modulator with timing function, a power drive circuit and an opto-isolation circuit, wherein the pulse width modulator is used to generate pulse signals of different amplitudes, the power drive is used to enhance the pulse signals to generate stable square wave signals, and the opto-isolation circuit is used to filter, amplify and level-convert the square wave signals to generate magnetoelectric rotational speed signals.

[0017] Preferably, the high-frequency vibration signal module includes several groups of high-frequency vibration signal simulation units, wherein each group of high-frequency vibration signal simulation units includes: a microprocessor and an oscillator, a pulse counter, a delay unit, a pulse width generator, a ramp generator, and an output amplifier respectively connected to the microprocessor, constituting a pulse signal generator; wherein, the main oscillator is used to generate a periodic square wave; the delay unit is used to delay the pulse signal; the pulse width generator is used to generate the required pulse width; the ramp generator is used to generate the leading edge and trailing edge of the pulse; the output amplifier is used to generate the required high level and low level of the pulse; the microprocessor is used to control the parameter setting and function switching of the oscillator, pulse counter, delay unit, pulse width generator, ramp generator, and output amplifier.

[0018] Preferably, the system further includes:

[0019] Thermocouple module, which is used to continuously simulate output signals from at least 32 K-type thermocouple temperature sensors.

[0020] Preferably, the thermocouple module includes several sets of thermocouple simulation units; wherein each set of thermocouple simulation units includes: a DAC digital-to-analog converter for outputting a voltage signal and an operational amplifier circuit for scaling down the voltage signal, simulating the output of a K-type thermocouple temperature sensor signal.

[0021] Preferably, the system further includes: a host computer, a main control module connected to the host computer via data communication, and an auxiliary control module connected to the main control module via data communication; the resistance temperature detector (RTD) module, the current signal module, the speed signal module, and / or the thermocouple module are connected to the main control module via digital isolation, and the high-frequency vibration signal module is connected to the main control module via digital isolation and the auxiliary control module via data communication.

[0022] According to a second aspect of the present invention, a method for simulating diesel engine operating signals is provided, comprising:

[0023] A resistance temperature detector (RTD) module is provided, through which the signal of a PT100 RTD temperature sensor is continuously simulated and output.

[0024] A current signal module is provided, through which a 4-20mA current-type sensor signal is continuously simulated and output;

[0025] A speed signal module is provided, through which the frequency-type speed signal digital switch dry contact signal is continuously simulated and output;

[0026] A high-frequency vibration signal module is provided, through which high-frequency vibration signals are continuously simulated and output.

[0027] Preferably, the above method further includes:

[0028] A thermocouple module is provided, through which the signal of a K-type thermocouple temperature sensor is continuously simulated and output.

[0029] Preferably, the above method further includes:

[0030] The generated analog signals are transmitted to the host computer via data communication for the development and research of a diesel engine operating status monitoring and fault diagnosis system.

[0031] By adopting the above technical solution, the present invention has at least one of the following beneficial effects compared with the prior art:

[0032] The diesel engine operation signal simulation system and method provided by this invention, through the design of each functional module, realizes the simulation of various operating signals of diesel engines, effectively reducing or replacing the actual vehicle operation of diesel engines.

[0033] The diesel engine operating signal simulation system and method provided by this invention include a thermal resistor module. By changing the input digital value of the D / A converter, the K value can be adjusted to change the synthesized resistance value, thereby effectively achieving the required resistance value.

[0034] The diesel engine operation signal simulation system and method provided by this invention include a current signal module with a precision voltage regulator that can provide independent power to external circuits, simplifying the design of external power supplies. It features high accuracy and low nonlinear error. A dedicated power transistor interface is designed to adapt to external NPN power transistors, and its parallel connection with the internal output transistors can reduce the chip's power consumption.

[0035] The diesel engine operation signal simulation system and simulation method provided by this invention adopts a modular and hierarchical design concept, which can reduce the size, reduce the processing burden of the main control system, and facilitate heat dissipation and maintenance. Attached Figure Description

[0036] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0037] Figure 1 This is a schematic diagram of the working principle of the resistance temperature detector (RTD) simulation unit of the RTD module in a preferred embodiment of the present invention.

[0038] Figure 2 This is a schematic diagram of the working principle of the thermocouple simulation unit of the thermocouple module in a preferred embodiment of the present invention.

[0039] Figure 3 This is a schematic diagram of the working principle of the current signal simulation unit of the current signal module in a preferred embodiment of the present invention.

[0040] Figure 4 This is a schematic diagram of the working principle of the high-frequency vibration signal simulation unit of the high-frequency vibration signal module in a preferred embodiment of the present invention.

[0041] Figure 5 This is a schematic diagram of the overall architecture of a diesel engine operation signal simulation system in a preferred embodiment of the present invention.

[0042] Figure 6 This is a flowchart illustrating the process of a diesel engine operation signal simulation method in a preferred embodiment of the present invention. Detailed Implementation

[0043] The embodiments of the present invention are described in detail below: These embodiments are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention.

[0044] One embodiment of the present invention provides a diesel engine operation signal simulation system. The system is based on hardware design to simulate various sensor signals during diesel engine operation, thereby reducing or replacing the actual operation of the diesel engine in a vehicle.

[0045] The diesel engine operating signal simulation system provided in this embodiment may include:

[0046] Thermocouple module, which is used to continuously output the signal of PT100 thermocouple temperature sensor in analog mode;

[0047] Current signal module, which is used to continuously simulate and output signals from a 4-20mA current-type sensor;

[0048] Speed ​​signal module, which is used to continuously analog output frequency-type speed signal digital switch dry contact signal;

[0049] High-frequency vibration signal module, which is used to continuously simulate and output high-frequency vibration signals.

[0050] In some preferred embodiments, the above-mentioned RTD module may further include: a plurality of RTD simulation units; wherein each group of RTD simulation units includes: an input operational amplifier U1, a D / A converter U4, an inverter U2, an output operational amplifier U3, and a standard resistor R. x ;in:

[0051] The input operational amplifier U1 is connected as a resistor follower, and its output voltage is U. i The reference voltage of the D / A converter U4 is used as the reference voltage; the D / A converter U4 proportionally adjusts the reference voltage to obtain an output voltage U. D / A =K ui , where K ui The value of U4 after proportional adjustment of the reference voltage; when the inverter U2 operates in linear amplification mode, the potentials at both input terminals are equal, then the voltage at the inverting terminal of the inverter U2 is K. ui ; This is how the force applied to the standard resistor R is obtained. x The voltage on is U i =UK ui Where U is the total external input voltage applied to the standard resistor R. x The current on is I i =(UK) ui ) / R, where R is the equivalent combined resistance of the PT100 resistance temperature sensor; the output operational amplifier U3 is used to increase the amplitude of the signal;

[0052] The input operational amplifier U1, D / A converter U4, inverter U2, output operational amplifier U3, and standard resistor R are used. x The simulated equivalent combined resistance R of the PT100 RTD temperature sensor is:

[0053] R = U i / I i =R x / (1+K) (1)

[0054] Among them, U i I is the output voltage of the input operational amplifier U1; i Let R be the current flowing through the combined resistor R. x is the standard resistor; K is the control coefficient, which is adjusted by changing the input digital value of the D / A converter U4.

[0055] In some preferred embodiments, the above-mentioned current signal module may further include: a plurality of groups of current signal simulation units, wherein each group of current signal simulation units includes: a signal amplification chip, a transistor, and a resistor R. inThe signal amplification chip controls the transistor to operate in the amplification region, and the resistor R in Connected in series between the pins of the transistor and the signal amplifier chip, the resistor R is detected. in The voltage is used to feedback and adjust the input of the transistor, thereby realizing the analog output of the current signal.

[0056] Furthermore, the internal reference voltage can serve as the excitation source for the signal amplification chip. The signal amplification chip can amplify the weak current signal of 40–200 μA generated by the front-end circuit by 100 times, obtaining a standard output of 4–20 mA; it can automatically limit the current when the loop current approaches 32 mA.

[0057] The signal amplification chip incorporates a +5V precision voltage regulator with an output voltage accuracy of ±0.05%, which can provide independent power to external circuits (such as preamplifiers), thereby simplifying the design of external power supplies.

[0058] The allowable range of the loop power supply voltage is 7.5 to 36V, and the signal amplification chip is powered by the loop power supply.

[0059] A power transistor interface is specially designed to accommodate external NPN power transistors. When connected in parallel with the internal output transistor, it can reduce the chip's power consumption.

[0060] In some preferred embodiments, the above-mentioned speed signal module may further include: at least one set of speed signal simulation units; wherein each set of speed signal simulation units includes: a pulse width modulator with timing function, a power drive circuit and an opto-isolation circuit, wherein the pulse width modulator is used to generate pulse signals of different amplitudes, the power drive is used to enhance the pulse signals to generate stable square wave signals, and the opto-isolation circuit is used to filter, amplify and level-convert the square wave signals to generate magnetoelectric speed signals.

[0061] In some preferred embodiments, the above-mentioned high-frequency vibration signal module may further include: a plurality of high-frequency vibration signal simulation units, wherein each of the high-frequency vibration signal simulation units includes: a microprocessor and an oscillator, a pulse counter, a delay unit, a pulse width generator, a ramp generator, and an output amplifier respectively connected to the microprocessor, constituting a pulse signal generator; wherein, the main oscillator is used to generate a periodic square wave; the delay unit is used to delay the pulse signal; the pulse width generator is used to generate the required pulse width; the ramp generator is used to generate the leading edge and trailing edge of the pulse; the output amplifier is used to generate the required high level and low level of the pulse; the microprocessor is used to control the parameter setting and function switching of the oscillator, pulse counter, delay unit, pulse width generator, ramp generator, and output amplifier.

[0062] In some preferred embodiments, the above system may further include:

[0063] Thermocouple module, which is used to continuously simulate the output signal of a K-type thermocouple temperature sensor.

[0064] In some preferred embodiments, the thermocouple module may further include: a plurality of thermocouple simulation units; wherein each of the thermocouple simulation units includes: a DAC digital-to-analog converter for outputting a voltage signal and an operational amplifier circuit for scaling down the voltage signal, thereby simulating the output of a K-type thermocouple temperature sensor signal.

[0065] In some preferred embodiments, the above system may further include: a host computer, a main control module connected to the host computer via data communication, and an auxiliary control module connected to the main control module via data communication; the resistance temperature detector (RTD) module, the current signal module, the speed signal module, and / or the thermocouple module are respectively connected to the main control module via digital isolation, and the high-frequency vibration signal module is connected to the main control module via digital isolation and the auxiliary control module via data communication.

[0066] The technical solution provided by the above embodiments of the present invention will be further described in detail below with reference to a specific application example.

[0067] In this specific application example, the diesel engine operating signal simulation system used includes:

[0068] Thermocouple module, which is used to continuously simulate output signals from at least 48 PT100 thermocouple temperature sensors;

[0069] Current signal module, which is used to continuously simulate output signals from at least 32 channels of 4-20mA current-type sensors;

[0070] Speed ​​signal module, which is used to continuously analog output at least 4 channels of frequency-type speed signal digital switch dry contact signals;

[0071] High-frequency vibration signal module, which is used to continuously simulate and output at least 40 channels of high-frequency vibration signals.

[0072] In this specific application example, the diesel engine operating signal simulation system may also include any one or more of the following:

[0073] - Thermocouple module, which is used to continuously simulate output signals from at least 32 K-type thermocouple temperature sensors;

[0074] -A host computer, a main control module connected to the host computer for data communication, and an auxiliary control module connected to the main control module for data communication; the RTD module, thermocouple module, current signal module, and speed signal module are connected to the main control module for data communication via digital isolation, and the high-frequency vibration signal module is connected to the auxiliary control module for data communication via digital isolation.

[0075] This diesel engine operation signal simulation system, based on the overall requirements of the condition monitoring and fault diagnosis system, simulates signals from at least 48 PT100 resistance temperature sensors, 32 K-type thermocouple temperature sensors, 32 4-20mA current sensors, 4 frequency-type speed signals, and 40 high-frequency vibration signals.

[0076] The main performance requirements for this diesel engine operation signal simulation system are as follows:

[0077] 1. It can continuously simulate and output signals from 48 PT100 resistance temperature sensors based on database data;

[0078] 2. It can continuously simulate and output signals from 32 K-type thermocouple temperature sensors based on database data;

[0079] 3. It can continuously simulate and output signals from 32 channels of 4-20mA current-type sensors based on database data;

[0080] 4. It can continuously simulate and output signals from the dry contacts of four frequency-type speed signals digital switches based on database data;

[0081] 5. It can continuously simulate and output 40 channels of high-frequency vibration signals based on database data.

[0082] Based on the overall system requirements and specific performance indicators, a diesel engine operation signal simulation system was designed, implemented as follows:

[0083] In the RTD section, the analog output of the RTD signal is designed;

[0084] Thermocouple section: Design of analog output for thermocouple signals;

[0085] The current signal section involves the design of the analog output of the current signal.

[0086] The speed signal section involves the design of the analog output of the speed signal.

[0087] The high-frequency vibration signal section designs the analog output of high-speed vibration signals.

[0088] Based on the aforementioned overall design objectives, this invention employs a modular and hierarchical design approach to construct a diesel engine operating signal simulation system, comprising: a resistance temperature detector (RTD) module, a thermocouple module, a current signal module, a speed signal module, and a high-frequency vibration signal module. Each module consists of multiple sub-modules. Each sub-module is digitally isolated and connected to the main control board. The main control board is connected via a network cable and transmits data via TCP.

[0089] in:

[0090] For the RTD module:

[0091] This section simulates the resistance of a PT100 resistance temperature sensor within a temperature range of 1-260℃, where the corresponding resistance variation range is 100-200Ω.

[0092] This section uses programmable synthesized resistors to simulate the resistance changes of the PT100 resistance temperature sensor. The structural principle of each set of resistance simulation units is as follows: Figure 1 As shown:

[0093] This part of the circuit structure consists of an input operational amplifier U1, a D / A converter, an inverter U2, an output operational amplifier U3, and a standard resistor R. x The circuit consists of a D / A converter as its core component. The basic operating principle is as follows: the input voltage at one end of the standard resistor is buffered, amplified, and proportionally adjusted before being fed back to the other end of the standard resistor. This feedback controls the input current, thereby determining the input resistance value.

[0094] Operational amplifier U1 is configured as a resistor follower, with an output voltage of Ui, which serves as the reference voltage for D / A converter U4. The D / A converter ensures good proportional output even when the reference voltage is reduced to near zero; its transfer factor K is determined by the input digital signal of U1. Therefore, the output voltage of the D / A converter is Ui. D / A =K ui Since the potentials at both input terminals of U2 are equal when U2 is operating in linear amplification mode, the voltage at the inverting terminal of U2 is K. ui Thus, the voltage applied across the standard resistor is U. i =UK ui The current is I i =(UK) ui Since the input current of operational amplifier U1 is zero, the combined resistance R = U / R at the input terminal is calculated. i / I iThe output operational amplifier U3 can increase the signal amplitude, creating a clear difference between the signal and noise, and filtering the signal to remove noise and interference. Analysis shows that, for the input terminal, the equivalent combined resistance R is:

[0095] R = U i / I i =R x / (1+K) (1)

[0096] Where R x The standard resistor is 200Ω in the design, with an accuracy of 0.01%. K is a control coefficient, K = D / 65535, so as it changes from 0 to 1, the equivalent combined resistance changes from R... x Change to R x / 2. By changing the input digital value of the D / A converter to adjust the K value, the synthesized resistance value can be changed, thereby achieving the actual required resistance value.

[0097] Regarding the thermocouple module:

[0098] This section simulates the voltage (mV) of a type K thermocouple temperature sensor within a temperature range of 1-1000℃. The structural principle of each thermocouple simulation unit is as follows: Figure 2 As shown:

[0099] The main component in this section, the DAC8568, is a low-power, voltage-output, 16-bit digital-to-analog converter. This device has an internal 2.5V, 2PPM / ℃ reference source, providing an output voltage range of 2.5V-5V. Its output is unidirectional and exhibits excellent linearity. Its interface is compatible with standard SPI, QSPI, and DSP interfaces. The DAC chip generates a level with an accuracy of 1 / 4096, which is then buffered by the OP1177 operational amplifier circuit to output an analog K-pair temperature value.

[0100] Using this device to output 8 voltage signals can reduce the number of signal analog boards and also reduce the number of fault points. The voltage signal output by the DAC8568 has a much higher amplitude than the thermocouple signal, so the signal needs to be scaled down. After the output voltage signal is driven by an operational amplifier follower, it is scaled down by a high-precision resistor network, and then driven by an operational amplifier for another stage to improve the driving capability of the output signal.

[0101] For the current signal module section:

[0102] This section can continuously simulate and output 32 channels of 4-20mA current signals, and the structural principle of each current signal simulation unit is as follows: Figure 3 As shown. The XTR116 is a two-wire current transmitter, and its characteristics are as follows:

[0103] (1) The internal 2.5V reference voltage can be used as the excitation source for the sensor. The XTR116 can amplify the weak current signal of 40-200μA generated by the sensor by 100 times to obtain a standard output of 4-20mA. It can automatically limit the current when the loop current approaches 32mA. The current limit value can be changed by connecting a resistor in parallel between pins 3 and 5.

[0104] (2) A +5V precision regulator has been added to the chip, with an output voltage accuracy of ±0.05% and a voltage temperature coefficient of only 20x10-6 / ℃. It can provide power to external circuits (such as preamplifiers) separately, thereby simplifying the design of external power supplies.

[0105] (3) High accuracy and low nonlinear error. The conversion accuracy can reach ±0.05%, and the nonlinear error is only ±0.003%.

[0106] (4) The allowable range of the loop power supply voltage is 7.5 to 36V. The XTR116 is powered by the loop power supply. The operating temperature range is -40 to +85℃.

[0107] (5) A power transistor interface is specially designed to adapt to external NPN power transistors. When connected in parallel with the internal output transistor, it can reduce the power consumption of the chip.

[0108] By inputting a value into the 16-bit DA converter, the output drives the XTR116 to generate different currents to simulate and restore the signal.

[0109] For the speed signal module:

[0110] This section mainly simulates the main shaft speed and turbocharger speed of the diesel engine (range: 30-32000). It mainly simulates the generation of pulse signals of different frequencies. The given frequency signal is generated by a high-speed timer PWM, and the high-speed opto-isolation circuit is driven by a power drive circuit to realize the dry junction output of the speed signal.

[0111] The pulse width modulator and preceding main oscillator circuits are used to generate pulse signals of different amplitudes (weak in intensity). The power drive and subsequent circuits are used to amplify this signal, generate a stable square wave signal, and filter, amplify, and level-convert the signal to generate a magnetoelectric rotation speed signal.

[0112] For the high-frequency vibration signal module:

[0113] Since vibration signals are also an important indicator of whether a diesel engine is operating normally, vibration signal restoration has been included in this section. It can generate 40 channels, each with a discrete voltage signal of ±5V amplitude at 2000 points per second. The main data source is the restoration of actual diesel engine operation test records.

[0114] Each high-frequency vibration signal simulation unit functions as a programmable pulse signal generator, primarily composed of oscillators, pulse counters, delay units, pulse width generators, ramp units (leading and trailing edges), output amplifiers, and microprocessors. The main oscillator unit generates a periodic square wave with a variable period, which can be synchronously triggered by an external signal. The pulse counter unit controls the number of output pulses in "BURST" mode. The delay unit delays the pulse signal. The pulse width generator forms the required pulse width. The ramp unit forms the leading and trailing edges of the pulse. The output amplifier unit generates the required high and low pulse levels. The microprocessor controls the parameter settings and function switching of all unit circuits. The structure of each high-frequency vibration signal simulation unit is as follows: Figure 4 As shown.

[0115] In some embodiments of the present invention:

[0116] Considering space, heat dissipation, and maintenance requirements, the system will adopt a modular and hierarchical design approach, dividing the entire signal analog module into five parts, each of which consists of multiple sub-boards. Each sub-board in each part is digitally isolated and connected to the main control board, which reduces the size, lightens the processing load on the main control system, and facilitates heat dissipation and maintenance.

[0117] Using a PC as the host computer for the simulation system provides multiple data interfaces for easy data transmission, supports a wide range of protocols, and facilitates the construction of a software monitoring platform.

[0118] The diesel engine operating signal simulation system provided in the above embodiments of the present invention has the following overall architecture: Figure 5 As shown.

[0119] One embodiment of the present invention provides a method for simulating diesel engine operating signals, such as... Figure 6 As shown, the method may include the following operations:

[0120] S1 provides a resistance temperature detector (RTD) module, through which the signal of the PT100 RTD temperature sensor is continuously simulated and output;

[0121] S2 provides a current signal module, through which the signal of a 4-20mA current-type sensor is continuously simulated and output;

[0122] S3 provides a speed signal module, through which the frequency-type speed signal digital switch dry contact signal is continuously simulated and output;

[0123] S4 provides a high-frequency vibration signal module, through which a high-frequency vibration signal is continuously simulated and output.

[0124] In some preferred embodiments, the above method may further include:

[0125] S5 provides a thermocouple module that continuously simulates and outputs signals from at least 32 K-type thermocouple temperature sensors.

[0126] In some preferred embodiments, the above method may further include:

[0127] S6 transmits various generated analog signals to the host computer via data communication for the development and research of a diesel engine operating status monitoring and fault diagnosis system.

[0128] It should be noted that the steps in the method provided by the present invention can be implemented using corresponding modules, devices, units, etc. in the system. Those skilled in the art can refer to the technical solution of the system to implement the steps and flow of the method. That is, the embodiments in the system can be understood as preferred examples of the method, and will not be elaborated here.

[0129] The diesel engine operation signal simulation system and method provided in the above embodiments of the present invention, through the design of each functional module, realizes the simulation of various operating signals of diesel engines, effectively reducing or replacing the actual vehicle operation of diesel engines; the design of the thermal resistor module allows the K value to be adjusted by changing the input digital quantity of the D / A converter, thereby changing the synthesized resistance value and effectively achieving the required resistance value; the design of the current signal module adds a precision voltage regulator, which can provide separate power supply to the external circuit, simplifying the design of the external power supply; it has high accuracy and small nonlinear error; a power transistor interface is specially designed to adapt to external NPN power transistors, and its parallel connection with the internal output transistor can reduce the power consumption of the chip; the modular and hierarchical design concept reduces the size, reduces the processing burden of the main control system, and facilitates heat dissipation and maintenance.

[0130] Those skilled in the art will understand that, in addition to implementing the system and its various devices provided by this invention in the form of purely computer-readable program code, the same functions can be achieved entirely through logical programming of the method steps, making the system and its various devices of this invention function as logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers. Therefore, the system and its various devices provided by this invention can be considered as a hardware component, and the devices included therein for implementing various functions can also be considered as structures within the hardware component; alternatively, the devices for implementing various functions can be considered as both software modules implementing the method and structures within the hardware component.

[0131] Any matters not covered in the above embodiments of the present invention are well-known in the art.

[0132] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A diesel engine operating signal simulation system, characterized in that, include: Thermocouple module, which is used to continuously output the signal of PT100 thermocouple temperature sensor in analog mode; The current signal module includes several groups of current signal simulation units, each group of which includes a signal amplification chip, a transistor, and a resistor. The signal amplification chip controls the transistor to operate in the amplification region, and the resistor... Connected in series between the pins of the transistor and the signal amplifier chip, the resistance is detected. The voltage is used to feedback and adjust the transistor input, thereby realizing the analog output of the current signal, which is used to continuously simulate the output of the 4-20mA current sensor signal; A speed signal module includes at least one set of speed signal simulation units; each set of speed signal simulation units includes: a pulse width modulator with timing function, a power drive circuit, and an opto-isolation circuit. The pulse width modulator is used to generate pulse signals of different amplitudes, the power drive is used to amplify the pulse signals to generate stable square wave signals, and the opto-isolation circuit is used to filter, amplify, and level-convert the square wave signals to generate magnetoelectric speed signals for continuous analog output of frequency-type speed signal digital switch dry contacts. A high-frequency vibration signal module includes several sets of high-frequency vibration signal simulation units for continuously simulating and outputting high-frequency vibration signals. Each set of high-frequency vibration signal simulation units includes a microprocessor and an oscillator, pulse counter, delay unit, pulse width generator, ramp generator, and output amplifier connected to the microprocessor, forming a pulse signal generator. The oscillator generates a periodic square wave; the delay unit delays the pulse signal; the pulse width generator forms the required pulse width; the ramp generator generates the leading and trailing edges of the pulse; and the output amplifier generates the required high and low pulse levels. The microprocessor controls the parameter settings and function switching of the oscillator, pulse counter, delay unit, pulse width generator, ramp generator, and output amplifier.

2. The diesel engine operating signal simulation system according to claim 1, characterized in that, The RTD module includes several sets of RTD simulation units; each set of RTD simulation units includes: an input operational amplifier U1, a D / A converter U4, an inverter U2, an output operational amplifier U3, and a standard resistor. ;in: The input operational amplifier U1 is connected as a resistor follower, and its output voltage is The reference voltage of the D / A converter U4 is used as the reference voltage; the D / A converter U4 proportionally adjusts the reference voltage to obtain an output voltage of... ,in, The value of U4 after proportional adjustment of the reference voltage; when the inverter U2 operates in linear amplification mode, the potentials at both input terminals are equal, then the voltage at the inverting terminal of the inverter U2 is... This is how the standard resistor is applied. The voltage on is ,in, The total external input voltage is applied to the standard resistor. The current on is ,in, The equivalent combined resistance of the PT100 resistance temperature sensor; the output operational amplifier U3 is used to increase the signal amplitude; The input operational amplifier U1, D / A converter U4, inverter U2, output operational amplifier U3, and standard resistor are used. The simulated equivalent combined resistance R of the PT100 RTD temperature sensor is: （1） in, The input voltage is the output voltage of operational amplifier U1; The current passing through the combined resistor R, is the standard resistor; K is the control coefficient, which is adjusted by changing the input digital value of the D / A converter U4.

3. The diesel engine operation signal simulation system according to claim 1, characterized in that, Also includes: Thermocouple module, which is used to continuously simulate the output signal of a K-type thermocouple temperature sensor.

4. The diesel engine operating signal simulation system according to claim 3, characterized in that, The thermocouple module includes several sets of thermocouple simulation units; each set of thermocouple simulation units includes: a DAC digital-to-analog converter for outputting a voltage signal and an operational amplifier circuit for scaling down the voltage signal, simulating the output of a K-type thermocouple temperature sensor signal.

5. The diesel engine operating signal simulation system according to any one of claims 1-4, characterized in that, Also includes: A host computer, a main control module connected to the host computer via data communication, and an auxiliary control module connected to the main control module via data communication. The resistance temperature detector (RTD) module, current signal module, speed signal module, and / or thermocouple module are connected to the main control module via digital isolation. The high-frequency vibration signal module is connected to the main control module via digital isolation and the auxiliary control module.

6. A method for simulating diesel engine operating signals, characterized in that, include: A resistance temperature detector (RTD) module is provided, through which the signal of a PT100 RTD temperature sensor is continuously simulated and output. A current signal module is provided, which continuously simulates and outputs a 4-20mA current-type sensor signal. The current signal module includes several sets of current signal simulation units, each set comprising a signal amplifier chip, a transistor, and a resistor. The signal amplification chip controls the transistor to operate in the amplification region, and the resistor... Connected in series between the pins of the transistor and the signal amplifier chip, the resistance is detected. The voltage is used to feedback and adjust the input of the transistor, thereby realizing the analog output of the current signal; A rotational speed signal module is provided, which continuously simulates and outputs the signal of the frequency-type rotational speed signal digital switch dry contact. The rotational speed signal module includes at least one set of rotational speed signal simulation units. Each set of rotational speed signal simulation units includes: a pulse width modulator with timing function, a power drive circuit, and an opto-isolation circuit. The pulse width modulator generates pulse signals of different amplitudes, the power drive circuit amplifies the pulse signals to generate stable square wave signals, and the opto-isolation circuit filters, amplifies, and levels the square wave signals to generate a magnetoelectric rotational speed signal. A high-frequency vibration signal module is provided, comprising several sets of high-frequency vibration signal simulation units, through which high-frequency vibration signals are continuously simulated and output. Each set of high-frequency vibration signal simulation units includes a microprocessor and an oscillator, pulse counter, delay unit, pulse width generator, ramp generator, and output amplifier, all connected to the microprocessor, forming a pulse signal generator. The oscillator generates a periodic square wave; the delay unit delays the pulse signal; the pulse width generator forms the required pulse width; the ramp generator generates the leading and trailing edges of the pulse; and the output amplifier generates the required high and low pulse levels. The microprocessor controls the parameter settings and function switching of the oscillator, pulse counter, delay unit, pulse width generator, ramp generator, and output amplifier.

7. The diesel engine operating signal simulation method according to claim 6, characterized in that, Also includes: A thermocouple module is provided, through which signals from at least 32 K-type thermocouple temperature sensors are continuously simulated and output. and / or The generated analog signals are transmitted to the host computer via data communication for the development and research of a diesel engine operating status monitoring and fault diagnosis system.

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