CN106499489B - Diesel engine particle catcher carbon loading amount detection device and detection method - Google Patents

Abstract

The invention discloses a firewoodThe carbon loading amount detection device comprises a detection coil, a power module, a controller module, a radio frequency amplification module and a data acquisition module, wherein the detection coil and a filter layer of a DPF carrier are placed in parallel and are arranged between a DPF carrier packaging layer at the bottom of the DPF carrier and a DPF carrier body, the detection coil is also connected with the data acquisition module and the radio frequency amplification module, and the power module, the data acquisition module, the radio frequency amplification module and the controller module are connected and provide power for the data acquisition module, the radio frequency amplification module and the controller module. The detection method comprises the following steps: 1. collecting a voltage amplitude a1 and a voltage amplitude b 1; 2. the detection coil transmits the received radio frequency signal to the data acquisition module; 3. to obtain | S₁₁L, |; 4. forming a database; 5. completing online detection; 6. and finishing the regeneration of the DPF carrier. Has the advantages that: meanwhile, the device has the advantages of simple detection device, high speed, high precision, reliable work and the like.

Description

Diesel engine particle catcher carbon loading amount detection device and detection method

Technical Field

The invention relates to a carbon loading detection device and a detection method, in particular to a carbon loading detection device and a detection method for a diesel particulate filter.

Background

Currently, with the continuous improvement of automobile keeping quantity in China, the emission standard of automobile exhaust is more and more strict. Because of the advantages of fuel saving, long service life and the like of the diesel engine, the trend that the modern automobile is driven by the gasoline engine to be driven by the diesel engine is more and more obvious, and the development of the diesel engine becomes an important development direction of the automobile industry at present. The diesel exhaust mainly includes carbon monoxide (CO), Hydrocarbons (HC), nitrogen oxides (NOx), soot (PM), and the like. Among them, soot emitted from a diesel engine needs to be removed by using a diesel particulate trap (DPF). The diesel DPF, which is a filter installed in an exhaust system of a diesel engine, is composed of a ceramic honeycomb carrier made of silicon carbide, and particles in exhaust gas can be trapped when the exhaust gas flows through the DPF carrier, and the device can reduce soot generated from the engine by more than 90%.

After a diesel DPF has been in operation for a period of time, the trapped soot particles build up, causing the diesel backpressure to increase, resulting in a decrease in diesel performance. In order to prevent the DPF from being clogged and affecting the diesel exhaust, it is necessary to periodically treat the particulate matter trapped in the particulate trap, i.e., regenerate the DPF.

Therefore, in the diesel particulate trap system, the detection of the state of the catalyst in the DPF plays a key role in the control of the system. The carbon loading (Soot loading) in the catalyst state is an important parameter.

Currently, methods for measuring carbon loading of a DPF are classified into: computational and empirical methods, and synthetic methods.

The calculation method is a method for calculating the carbon loading of the DPF by using a related mathematical or physical formula.

The carbon loading is obtained by obtaining a difference between the PM discharge amount and the natural PM regeneration amount. Or dividing the increment part of the carbon accumulation amount into three parts of carbon deposition amount change caused by the change of the total flow resistance, carbon deposition amount change caused by the mass of ash and carbon deposition amount change caused by the volume flow of waste gas, and calculating by using a related formula to obtain the carbon accumulation amount.

The carbon loading is judged by an empirical method mainly by determining a curve or a MAP (MAP) chart formed by the relationship between parameters such as the pressure difference value at two ends of the DPF, the exhaust gas flow in an exhaust pipe, the temperature of the DPF and the carbon loading, and then checking the chart to determine the real-time carbon loading.

In the specific implementation process, the carbon loading amount estimated value of the DPF can be obtained by looking up a corresponding table of the differential pressure value and the carbon loading amount, and the accuracy is improved by correcting parameters such as airflow temperature and the like; calibrating the carbon loading capacity of the DPF of the engine by utilizing the universal characteristic curve of the engine; calibrating an ash component MAP based on a pressure difference across the DPF and an exhaust gas flow rate in the exhaust pipe (temperature of the DPF); and determining a standard pressure difference calibration curve of the standard pressure difference and the accumulated carbon amount by using an idle state equation.

And the comprehensive method is a comprehensive experience method and a calculation method, the DPF carbon loading amount is detected by the two methods at the same time, and the two data are mutually calibrated to obtain more accurate DPF carbon loading amount data.

If a DPF pressure difference model is established to obtain a first carbon loading amount, and then a second carbon loading amount is calculated for the PM discharging amount and the regeneration amount, and carbon loading data with higher accuracy is reserved. Or obtaining the second carbon loading capacity through a MAP (MAP of the running condition and the carbon particle loading speed), and comprehensively judging the carbon loading capacity by combining the two modes.

In the process of obtaining the carbon loading amount based on the methods such as the differential pressure, the exhaust gas flow, the PM discharge amount and the regeneration amount and the comprehensive method thereof, a large number of sensors are needed, the cost is high, the accuracy degree of the sensors often depends on the accuracy of the sensors and the accuracy of a calculation model, large errors exist under certain working conditions, the carbon loading amount in the DPF cannot be accurately estimated under special extreme conditions, and the regeneration time of the DPF is directly influenced.

The DPF internal carbon loading amount can be accurately obtained at a low cost by using an optical method and an electromagnetic method. DPF carbon loading may also be detected, for example, by scattering of light by PM particles. Or DPF carbon loading may be detected by radio frequency techniques.

By utilizing the principle that the carbon loading amount of the DPF of the diesel engine is different and the resonant frequency of the DPF is different, the carbon loading amount in the DPF can be directly measured without depending on data of other sensors. The electromagnetic characteristic change condition measured by the method is measured by taking the ceramic honeycomb filter body, the coating, other metal catalysts and the like in the DPF as a whole, and the method has the advantages of high speed, higher measurement precision, strong anti-interference capability, simplicity in operation, accurate result and the like, and the mechanical noise of the engine has no influence on radio frequency transmission and reception.

In the patent of a method and equipment for realizing accurate regeneration of DPF by detecting carbon accumulation amount based on radio frequency technology (application number: 201610309409.0), a method for measuring the carbon accumulation amount in a DPF filter body in real time based on the corresponding relation between RF resonance frequency and carbon accumulation amount is provided. The system detects the resonant frequency by an RF generator and an RF receiver which are arranged on the upper and the lower streams of the DPF, radiates a radio frequency signal and receives the radio frequency signal transmitted by the DPF. In the selection of the device and the position relation between the DPF and the antenna, the invention adopts the mode that two devices of radio frequency emission and reception are respectively arranged at the upper stream and the lower stream of the DPF, and the structure is more complex; in the process of processing the radio frequency signals, the method of carrying out Fourier transform on the transmitted radio frequency signals to obtain the maximum point of an energy spectrum curve is adopted to finish the calibration of the resonant frequency.

Disclosure of Invention

The invention aims to solve the problems of the existing DPF carbon loading amount detection device and method, and provides a diesel particulate filter carbon loading amount detection device and method.

The invention provides a carbon loading amount detection device of a diesel particulate filter, which comprises a detection coil, a power supply module, a controller module, a radio frequency amplification module and a data acquisition module, wherein the detection coil is arranged in parallel with a filter layer of a DPF carrier and is arranged between a DPF carrier packaging layer at the bottom of the DPF carrier and a DPF carrier body, the detection coil periodically emits radio frequency from one frequency to the other frequency, the radio frequency is reflected in the DPF carrier and then received by the original detection coil again, the detection coil is also connected with the data acquisition module and the radio frequency amplification module, the data acquisition module and the radio frequency amplification module are both connected with the controller module and controlled by the controller module to work, and the power supply module, the data acquisition module, the radio frequency amplification module and the controller module are all connected and provide electric power for the data acquisition module, the radio frequency amplification module and the controller module.

The data acquisition module mainly comprises a coil, a communication chip and a storage chip and is used for receiving the reflected radio frequency signals and sending the received radio frequency signals to a main control chip in the controller module for calculation and analysis so as to carry out the next control.

The radio frequency amplification module is mainly composed of a radio frequency generator, a power amplifier and a coil, the radio frequency amplification module is controlled by a main control chip in a controller module to work and is used for generating radio frequency signals with different frequencies transmitted to the DPF carrier, the radio frequency generator is powered by a power supply, direct current electric energy is converted into electromagnetic energy, electromagnetic oscillation is excited in the radio frequency generator, therefore, radio frequency signals with corresponding frequencies are generated in corresponding time periods and transmitted to a detection coil placed at the bottom of the DPF carrier, and the radio frequency signals are radiated out through the detection coil.

The controller module mainly comprises a main control chip, a communication chip and a plurality of interfaces and is used for radio frequency signal control, signal processing, carbon loading amount estimation and ECU equipment communication, the main control chip sends out a driving signal to control the radio frequency amplification module, the data acquisition module acquires a reflected radio frequency signal and sends the reflected radio frequency signal back to the controller module, the controller module receives the signal and calculates and compares the signal to obtain the current carbon loading amount in the DPF carrier, and the interfaces arranged on the controller module are connected with and communicate with the ECU equipment in the engine.

The detection coil, the power supply module, the controller module, the radio frequency amplification module, the data acquisition module and the ECU device are all assembled by existing equipment, and therefore specific models and specifications are not further described.

The invention provides a method for detecting carbon loading of a diesel particulate filter, which comprises the following steps:

step one, recording voltage amplitude a1 caused by radio frequency signals emitted by a DPF carrier at the same port and voltage amplitude b1 caused by received reflected radio frequency signals when the DPF carrier is under the same carbon loading amount and different frequencies;

step two, the detection coil transmits the received radio frequency signal to the data acquisition module, and the data acquisition module sends the data to a main control chip in the controller module through the communication unit for calculation, as shown in the following formula:

wherein, because the detection coil is only arranged at the bottom of the DPF carrier, when a₂When the content is equal to 0, the content,

|S₁₁i is return loss in dB, | S₁₁I can change along with the change of the internal parameters of the resonant cavity, and describes the condition of energy transmission in the resonant cavity, so that the change condition of the carbon loading in the DPF carrier is reflected;

step three, obtaining | S under different frequencies with the frequency of 500MHz to 2500MHz and the step length of 100KHz under the same DPF carbon loading state₁₁I, when S₁₁The corresponding frequency when | takes the minimum value is the frequency when the resonant cavity resonates, because | S₁₁I has a one-to-one correspondence with the resonant frequency, and S is adopted₁₁I is used for calibrating the resonant frequency, and when the I is S under the same carbon loading amount₁₁Calculating the resonance frequency when the I reaches the minimum value, and when the carbon loading amount in the DPF carrier is different, I S₁₁The resonant frequency of the corresponding resonant cavity is different when the minimum value is obtained, so that the numerical value of each resonant frequency corresponds to different carbon loading states in the DPF carrier;

establishing corresponding relations between different carbon loading amounts and resonant frequencies under different frequencies ranging from 500MHz to 2500MHz and with the step length of 100KHz, forming a database and writing the database into a main control chip;

step five, the device is installed in a diesel engine post-processing system, when the engine starts to work, the radio frequency amplification module generates a frequency sweep signal, the main control chip receives the collected radio frequency signal data, and the minimum echo loss | S in a frequency sweep period is obtained through calculation₁₁The value of | is calculated and the echo with the minimum generation is calculatedLoss of S₁₁Matching the resonance frequency at the moment of the | numerical value with the resonance frequency data in the database to obtain the real-time carbon loading amount, and completing the on-line detection of the DPF carbon loading amount;

and step six, when the carbon loading amount in the DPF carrier reaches a preset value, the controller module sends a regeneration signal to ECU equipment in the engine, and regeneration of the DPF carrier is completed under the control of the ECU equipment of the engine.

The working principle of the invention is as follows:

in the selection of the device, the detection coil for transmitting and receiving the radio frequency signals is arranged at one position of the DPF carrier, and the resonance frequency is detected by the radio frequency signals reflected by the DPF carrier, so that the circuit for transmitting and receiving the signals can be integrated at one position, the structure of the detection device is simplified, and the operation is easy. And the detection coil and the DPF carrier filtering layer are arranged in parallel on the position relation between the DPF carrier and the detection coil and are arranged at the bottom of the DPF carrier, namely between the DPF carrier packaging layer and the DPF carrier. Because the DPF carrier is packaged by the metal material, the detection coil is arranged between the metal material and the DPF carrier, so that the detection coil is not influenced by external interference, and the measurement precision is improved. If the detection coil is arranged in the airflow direction, the shielding layer cannot be arranged, and meanwhile, soot particles in the exhaust gas can be accumulated on the coil located at the upstream of the DPF, so that the measurement accuracy is affected. When the radio frequency signal is processed, the detection coil is adopted to transmit the radio frequency signal and simultaneously receive the reflected radio frequency signal, and the return loss | S is obtained through calculation₁₁And l, calibrating the resonant frequency by finding out the resonant frequency corresponding to the minimum value of the parameter.

The invention has the beneficial effects that:

the invention provides a device and a method for detecting carbon loading of a diesel particulate filter, which are used for converting the process of capturing carbon smoke particles in the working process of a DPF carrier into an observable numerical value by utilizing a radio frequency technology. By comparing the return loss | S₁₁Recording the minimum value of | under different carbon carrying quantity, and calculating the current | S₁₁Obtaining the corresponding frequency when the minimum value is obtained, namely the resonant frequency of the DPF carrier at the moment, and establishing the resonant frequency of the DPF carrier and carbon plusAnd a detection database of the load capacity. Sending real-time DPF carrier internal radio frequency signals back to a main control chip of a controller module to obtain a return loss value | S₁₁Calculating to obtain | S in a sweep frequency period₁₁And | acquiring the corresponding resonant frequency when the minimum value is obtained, comparing the calculated resonant frequency with the resonant frequency value in the database to obtain the real-time carbon loading amount in the DPF carrier, and finishing the detection of the state of the catalyst in the DPF carrier so as to regenerate the DPF carrier.

The method for detecting the carbon loading amount in the DPF carrier by using the radio frequency detection is a non-contact detection method, has small interference on the working DPF carrier, and has the advantages of simple detection device, high speed, high precision, reliable work and the like.

Drawings

FIG. 1 is a schematic view of the structure of the device of the present invention.

Fig. 2 is a schematic view of the installation position of the detection coil according to the present invention.

FIG. 3 is | S₁₁And | detecting a frequency spectrum schematic diagram.

1. Detection coil 2, power module 3, controller module 4, radio frequency amplification module

5. Data acquisition module 6, DPF carrier 7, encapsulation layer 8, ECU equipment.

Detailed Description

Please refer to fig. 1, fig. 2 and fig. 3:

the invention provides a carbon loading amount detection device of a diesel particulate filter, which comprises a detection coil 1, a power module 2, a controller module 3, a radio frequency amplification module 4 and a data acquisition module 5, the detection coil 1 and the filter layer of the DPF carrier 6 are placed in parallel and are arranged between the packaging layer 7 of the DPF carrier 6 at the bottom of the DPF carrier 6 and the body of the DPF carrier 6, the detection coil 1 periodically emits radio frequency from one frequency to the other frequency, the radio frequency is received by the original detection coil 1 again after being reflected inside the DPF carrier 6, the detection coil 1 is also connected with the data acquisition module 5 and the radio frequency amplification module 4, the data acquisition module 5 and the radio frequency amplification module 4 are both connected with the controller module 3 and controlled by the controller module 3 to work, and the power supply module 2, the data acquisition module 5, the radio frequency amplification module 4 and the controller module 3 are all connected and provide power for the data acquisition module 5, the radio frequency amplification module 4 and the controller module 3.

The data acquisition module 5 mainly comprises a coil, a communication chip and a storage chip, and is used for receiving the reflected radio frequency signal and sending the received radio frequency signal to a main control chip in the controller module 3 for calculation and analysis so as to perform the next control.

The radio frequency amplification module 4 mainly comprises a radio frequency generator, a power amplifier and a coil, wherein the radio frequency amplification module 4 is controlled by a main control chip in the controller module 3 to work and is used for generating radio frequency signals with different frequencies transmitted to the DPF carrier 6, the radio frequency generator is powered by a power supply and converts direct current electric energy into electromagnetic energy to excite electromagnetic oscillation in the radio frequency generator, so that radio frequency signals with corresponding frequencies are generated in corresponding time periods and are transmitted to the detection coil 1 placed at the bottom of the DPF carrier 6, and the radio frequency signals are radiated out through the detection coil 1.

The controller module 3 mainly comprises a main control chip, a communication chip and a plurality of interfaces, and is used for radio frequency signal control, signal processing, carbon loading estimation and ECU equipment 8 communication, the main control chip sends out a driving signal to control the radio frequency amplification module 4, the reflected radio frequency signal is collected by the data collection module 5 and sent back to the controller module 3, the controller module 3 receives the driving signal and calculates and compares the current carbon loading in the DPF carrier 6, and the controller module 3 is also provided with an interface to be connected with and communicate with the ECU equipment 8 in the engine.

The detection coil 1, the power module 2, the controller module 3, the radio frequency amplification module 4, the data acquisition module 5 and the ECU device 8 are all assembled by existing devices, and therefore specific models and specifications are not further described.

The invention provides a method for detecting carbon loading of a diesel particulate filter, which comprises the following steps:

firstly, recording voltage amplitude a1 caused by radio frequency signals emitted by the DPF carrier 6 at the same port and voltage amplitude b1 caused by received reflected radio frequency signals when the DPF carrier 6 is under the same carbon loading and different frequencies;

step two, the detection coil 1 transmits the received radio frequency signal to the data acquisition module 5, and the data acquisition module 5 sends the data to a main control chip in the controller module 3 through a communication unit for calculation, as shown in the following formula:

wherein, because the detection coil 1 is only placed at the bottom of the DPF carrier 6, when a₂When the content is equal to 0, the content,

|S₁₁i is return loss in dB, | S₁₁I can change along with the change of the internal parameters of the resonant cavity, and describes the condition of energy transmission in the resonant cavity, so as to reflect the change condition of the carbon loading amount in the DPF carrier 6;

step three, obtaining | S under different frequencies with the frequency of 500MHz to 2500MHz and the step length of 100KHz under the state of the same 6 carbon loading amount of the DPF carrier₁₁I, when S₁₁The corresponding frequency when | takes the minimum value is the frequency when the resonant cavity resonates, because | S₁₁I has a one-to-one correspondence with the resonant frequency, and S is adopted₁₁I is used for calibrating the resonant frequency, and when the I is S under the same carbon loading amount₁₁Calculating the resonance frequency when | reaches the minimum value, and | S when the carbon loading amount in the DPF carrier 6 is different₁₁The corresponding resonant cavities have different resonant frequencies when the minimum value is obtained, so that the numerical value of each resonant frequency corresponds to different carbon loading states in the DPF carrier 6;

establishing corresponding relations between different carbon loading amounts and resonant frequencies under different frequencies ranging from 500MHz to 2500MHz and with the step length of 100KHz, forming a database and writing the database into a main control chip;

step five, the device is installed in a diesel engine post-processing system, and when the engine starts to work, the radio frequency amplification module generates a sweep frequency signalAnd the main control chip receives the acquired radio frequency signal data, and the minimum echo loss | S in a frequency sweep period is obtained after calculation₁₁The value of | is calculated and the S which produces the minimum return loss | is calculated₁₁Matching the resonance frequency at the moment of the | numerical value with the resonance frequency data in the database to obtain real-time carbon loading, and completing the online detection of the 6 carbon loading of the DPF carrier;

and step six, when the carbon loading amount in the DPF carrier 6 reaches a preset value, the controller module 3 sends a regeneration signal to an ECU device 8 in the engine, and regeneration of the DPF carrier 6 is completed under the control of the engine ECU device 8.

Claims (1)

1. A detection method of a carbon loading detection device of a Diesel Particulate Filter (DPF) comprises a detection coil, a power module, a controller module, a radio frequency amplification module and a data acquisition module, the detection coil and the filter layer of the DPF carrier are placed in parallel and are arranged between a DPF carrier packaging layer at the bottom of the DPF carrier and a DPF carrier body, the detection coil periodically emits radio frequency from one frequency to the other frequency, the radio frequency is received by the original detection coil again after being reflected inside the DPF carrier, the detection coil is also connected with a data acquisition module and a radio frequency amplification module, the data acquisition module and the radio frequency amplification module are both connected with a controller module and are controlled by the controller module to work, and a power supply module, the data acquisition module, the radio frequency amplification module and the controller module are all connected with one another and provide power for the data acquisition module, the radio frequency amplification module and the controller module;

the detection steps are as follows:

step one, recording voltage amplitude a1 caused by radio frequency signals emitted by a DPF carrier at the same port and voltage amplitude b1 caused by received reflected radio frequency signals when the DPF carrier is under the same carbon loading amount and different frequencies;

step two, the detection coil transmits the received radio frequency signal to the data acquisition module, and the data acquisition module sends the data to a main control chip in the controller module through the communication unit for calculation, as shown in the following formula:

|S₁₁i is return loss in dB, | S₁₁I can change along with the change of the internal parameters of the resonant cavity, and describes the condition of energy transmission in the resonant cavity, so that the change condition of the carbon loading in the DPF carrier is reflected;

step three, obtaining | S under different frequencies with the frequency of 500MHz to 2500MHz and the step length of 100KHz under the same DPF carrier carbon loading state₁₁I, when S₁₁The corresponding frequency when | takes the minimum value is the frequency when the resonant cavity resonates, because | S₁₁I has a one-to-one correspondence with the resonant frequency, and S is adopted₁₁I is used for calibrating the resonant frequency, and when the I is S under the same carbon loading amount₁₁Calculating the resonance frequency when the I reaches the minimum value, and when the carbon loading amount in the DPF carrier is different, I S₁₁The resonant frequency of the corresponding resonant cavity is different when the minimum value is obtained, so that the numerical value of each resonant frequency corresponds to different carbon loading states in the DPF carrier;

establishing corresponding relations between different carbon loading amounts and resonant frequencies under different frequencies ranging from 500MHz to 2500MHz and with the step length of 100KHz, forming a database and writing the database into a main control chip;

step five, the detection device is installed in a diesel engine post-processing system, when the engine starts to work, the radio frequency amplification module generates a frequency sweep signal, the main control chip receives the collected radio frequency signal data, and the minimum echo loss | S in a frequency sweep period is obtained through calculation₁₁The value of | is calculated and the S which produces the minimum return loss | is calculated₁₁Matching the resonance frequency at the moment of the | numerical value with the resonance frequency data in the database to obtain real-time carbon loading, and completing the on-line detection of the carbon loading of the DPF carrier;

and step six, when the carbon loading amount in the DPF carrier reaches a preset value, the controller module sends a regeneration signal to ECU equipment in the engine, and regeneration of the DPF carrier is completed under the control of the ECU equipment of the engine.

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