CN106437948A - DPF regenerating system and control method - Google Patents

Abstract

The invention provides a DPF regeneration system and a control method. The system mainly includes an NTP injection system, a double DPF system, a thermoelectric conversion device and a control module. The NTP injection system uses air as the gas source, discharges through the NTP generator to generate active substances, sprays out from the nozzle installed at the front end of the DPF, and enters the interior of the DPF to participate in regeneration. The dual DPF system includes two parallel DPFs to ensure that the diesel engine can run normally when the NTP injection system alternately regenerates the DPFs online. The thermoelectric conversion device controls the temperature of the DPF by using the electric heating layer wrapped in the DPF shell, so that the DPF is at an optimal regeneration temperature. The NTP injection system, double DPF system and thermoelectric conversion device are all connected to the control module. The invention can regenerate the DPF online in real time under the running state of the diesel engine, and effectively solves the problem that the NTP utilization rate decreases due to excessive exhaust gas flow.

Description

A DPF regeneration system and control method

technical field

The invention relates to the technical field of post-treatment of diesel engine exhaust, in particular to a DPF regeneration system and a control method.

Background technique

Due to its good fuel economy, high reliability, high thermal efficiency and long service life, diesel engines are widely used in transportation, industrial and agricultural production and other fields. The main pollutants emitted by diesel engines are nitrogen oxides NO _X and particulate matter (PM for short), especially PM, which seriously endanger human health. In recent years, increasingly stringent emission regulations have put forward higher requirements on PM emissions from diesel engines. Diesel particulate filter (DPF for short) technology is considered to be the most effective post-treatment method to reduce PM at present, and the collection efficiency can reach more than 90%. However, as the DPF continues to capture PM in the exhaust, the DPF will be blocked, which will lead to the consequences of increased exhaust back pressure, performance degradation, and increased fuel consumption of the diesel engine. Therefore, the key to DPF technology is to timely remove the PM adsorbed by the DPF. , that is, the regeneration of the DPF.

Traditional DPF regeneration methods are mainly divided into active regeneration and passive regeneration. Active regeneration includes fuel injection heating regeneration, electric heating regeneration, microwave heating regeneration and infrared heating regeneration and other thermal regeneration methods. Thermal regeneration technology mainly uses external energy to heat and burn off the PM deposited on the DPF. The reaction temperature is usually as high as 600°C or higher, and the carrier is easily damaged due to local overheating. Passive regeneration mainly includes catalytic regeneration and continuous regeneration. Compared with thermal regeneration, catalytic regeneration technology and continuous regeneration technology with catalyst can greatly reduce the reaction temperature of PM, but the temperature range in which the catalyst maintains activity is narrow, and the requirements for oil products are higher. Therefore, the traditional DPF regeneration method has its own shortcomings, and its use is limited.

Low-temperature plasma (Non-thermal plasma, NTP) technology has the advantages of high efficiency, wide range of treatment, thorough purification and simultaneous treatment of multiple pollutants in the field of pollutant treatment. Great application prospects. The NTP generator produces strong oxidizing active substances such as O ₃ and NO ₂ through high-voltage discharge of the air source. The essence of NTP regeneration DPF technology is that the active substances such as O ₃ and NO ₂ produced by it undergo complex chemical reactions with PM deposited in the DPF, and realize the oxidative decomposition of PM at a temperature far below the ignition temperature of PM to achieve the removal of PM the goal of. At present, the use of NTP technology to reduce diesel engine emissions has achieved certain research results. A method for regenerating the DPF using NTP technology when the diesel engine is shut down is described in the Chinese patent application with the Chinese publication number CN102678238A. This method selectively uses the waste heat of the exhaust gas of the diesel engine and electric heating to make the DPF reach the regeneration temperature, and realizes the off-line of the DPF regeneration. However, this method has the disadvantages that it cannot regenerate the DPF in real time online, and it cannot provide an effective online regeneration strategy for the DPF system that the diesel engine runs for a long time. The Chinese patent application with the Chinese publication number CN105221220A provides a regeneration strategy that uses NTP technology to perform online regeneration and offline regeneration of the DPF. This strategy can regenerate the DPF in real time when the diesel engine is running, and completely regenerate the DPF periodically. However, the disadvantage of this method is that the exhaust gas flow rate is much greater than the NTP flow rate during online regeneration, and this method fails to solve the problems of decreased NTP utilization rate and low regeneration efficiency.

Contents of the invention

Aiming at the deficiencies in the prior art, the present invention provides a DPF regeneration system and control method, which adopts a regeneration strategy combining online regeneration and offline regeneration, and uses an NTP injection system and a thermoelectric conversion device to perform online alternate regeneration of a dual DPF system , greatly improving the NTP utilization rate and regeneration efficiency during online regeneration.

The present invention achieves the above-mentioned technical purpose through the following technical means.

A DPF regeneration system includes an NTP injection system, a double DPF system and a control module; the NTP injection system includes an NTP generator, an air supply fan, a mass flow controller, an oscilloscope, a power supply, an injection pipeline, and a nozzle; the supply The gas fan is connected to the inlet end of the NTP generator through a pipeline equipped with a mass flow controller, and the gas outlet end of the NTP generator is connected to the nozzle through an injection pipeline, and the rear section of the injection pipeline is divided into two injection branches. The first NTP control valve and the second NTP control valve are respectively installed on the two injection branches, the end of the injection branch with the first NTP control valve is connected to the first nozzle, and the injection with the second NTP control valve is installed The end of the branch is connected to the second nozzle;

The dual DPF system includes a first DPF and a second DPF, the first DPF and the second DPF are connected in parallel through an exhaust branch, and a first exhaust control valve is installed on the exhaust branch at the front end of the first DPF , a first differential pressure sensor is installed on the exhaust branch of the first DPF; a second exhaust control valve is installed on the exhaust branch at the front end of the second DPF, and a second differential pressure sensor;

The first nozzle and the second nozzle in the NTP injection system are respectively installed at the inlets of the first DPF and the second DPF, the first NTP control valve, the second NTP control valve, the first exhaust control valve, the first The second exhaust control valve, the first differential pressure sensor and the second differential pressure sensor are all connected to the control module.

The control module pre-stores the DPF pressure difference upper limit threshold ΔP _c , and the target pressure difference ΔP ₀ marking the completion of DPF regeneration, and collects the pressure difference ΔP ₁ at both ends of the first DPF and/or the pressure at both ends of the second DPF through the pressure difference sensor in real time. difference ΔP ₂ , according to the pre-stored DPF pressure difference upper limit threshold ΔP _c and the real-time detected pressure difference ΔP ₁ across the first DPF and/or the pressure difference ΔP ₂ across the second DPF to determine whether DPF regeneration is required; and by controlling the The opening and closing of an NTP control valve, the second NTP control valve, the first exhaust control valve, the second exhaust control valve, and the opening and closing of the NTP injection system realize online regeneration or shutdown of the first DPF and/or the second DPF regeneration.

Preferably, a first temperature sensor and a second temperature sensor are respectively installed downstream of the first DPF and the second DPF, and the shells of the first DPF and the second DPF are respectively wrapped with first electric heaters connected to a power supply. layer and the second electric heating layer, the first temperature sensor and the second temperature sensor are both connected to the control module;

The optimal temperature range of regeneration T _f ~ T _c is pre-stored in the control module, and the control module is also based on the temperature T ₁ of the first DPF and the temperature T ₂ of the second DPF, when performing online regeneration or shutdown regeneration , control T ₁ and/or T ₂ to be within the optimal temperature range T _f ~ T _c for regeneration.

Preferably, a thermoelectric conversion device is also included, and the thermoelectric conversion device is installed on the front exhaust pipeline of the double DPF system to provide electric energy for the first electric heating layer and the second electric heating layer.

Preferably, the installation positions of the first nozzle and the second nozzle are respectively 100 mm away from the front faces of the first DPF and the second DPF.

Preferably, the NTP injection system adopts a water-cooled cooling system, and the cooling water enters the NTP generator through the water inlet and is discharged through the water outlet; the voltage and frequency of the power supply of the NTP injection system can be adjusted.

Preferably, the NTP generator is a dielectric barrier discharge type, including a fine wire mesh outer electrode, a quartz tube and a stainless steel tube inner electrode; the fine wire mesh outer electrode is wrapped on the outer wall of the quartz tube, and the stainless steel tube inner electrode is installed inside the quartz tube, A discharge gap with a circular section is formed between the inner electrode of the stainless steel tube and the quartz tube, and the outer electrode of the fine wire mesh is a discharge area.

Preferably, the first electric heating layer and the second electric heating layer are powered by the vehicle battery when the diesel engine is stopped.

The DPF regeneration control method of described DPF regeneration system, comprises the steps:

Step 1: Carry out a calibration test on the dual DPF system, determine the DPF pressure difference upper limit threshold ΔP _c corresponding to the diesel engine under different working conditions, and mark the regeneration target pressure difference ΔP ₀ after DPF regeneration is completed; set the pressure difference upper limit threshold ΔP _c , regeneration target The pressure difference ΔP ₀ is stored in the control module;

Step 2: The control module monitors the pressure difference ΔP ₁ and ΔP ₂ at the front and rear ends of the first DPF and the second DPF through the first differential pressure sensor and the second differential pressure sensor, and compares them with the pre-stored pressure difference upper limit threshold ΔP _c in the control module , to determine whether regeneration is required;

When the control module detects that the pressure difference ΔP ₁ between the front and back ends of the first DPF is greater than the upper limit threshold ΔPc of the pressure difference and the pressure difference ΔP ₂ between the front and rear ends of the second DPF is smaller than the upper limit threshold ΔP _c of the pressure difference, it is considered that the first DPF needs to be regenerated; if at this time If the second exhaust control valve is in the closed state, then open the second exhaust control valve and make a new determination; if the second exhaust control valve is in the open state at this time, then close the first exhaust control valve and perform online regeneration. Send a signal to start the NTP injection system, open the first NTP control valve, inject active gas from the front end of the first DPF, and regenerate the first DPF; the control module monitors that the pressure difference ΔP ₁ between the front and rear ends of the first DPF is less than the regeneration target pressure difference When ΔP is ₀ , it is considered that the regeneration is completed; the control module sends a signal to close the first NTP control valve, open the first exhaust control valve, and close the NTP injection system;

When the control module detects that the pressure difference ΔP ₂ at the front and rear ends of the second DPF is greater than the upper limit threshold ΔP _c of the pressure difference and the pressure difference ΔP ₁ at the front and rear ends of the first DPF is less than the upper limit threshold ΔP _c of the pressure difference, it is considered that the second DPF needs to be regenerated; if so When the first exhaust control valve is closed, open the first exhaust control valve and re-determine; if the first exhaust control valve is open at this time, close the second exhaust control valve to perform online regeneration and The module sends a signal to start the NTP injection system, opens the second NTP control valve, injects active gas from the front end of the second DPF, and regenerates the second DPF; the control module monitors that the pressure difference ΔP ₂ between the front and rear ends of the second DPF is less than the regeneration target pressure When the difference ΔP is ₀ , it is considered that the regeneration is completed; the control module sends a signal to close the second NTP control valve, open the second exhaust control valve, and close the NTP injection system;

When the control module detects that the pressure difference between the front and rear ends of the first DPF and the second DPF is greater than the pressure difference upper limit threshold ΔP _c , it is considered that both need to be regenerated; at this time, in order to ensure smooth exhaust, the control module controls the first exhaust control valve and the second exhaust control valve remain open, and after receiving the shutdown signal of the diesel engine, the first exhaust control valve and the second exhaust control valve are closed to perform shutdown regeneration, the control module sends a signal to start the NTP injection system, and the first The NTP control valve and the second NTP control valve inject active gas into the front end of the first DPF and the second DPF respectively to regenerate the first DPF and the second DPF; when the control module monitors the pressure difference between the front and back ends of the first DPF ΔP ₁ , When the pressure difference ΔP ₂ at the front and back ends of the second DPF is less than the regeneration target pressure difference ΔP ₀ , the regeneration is considered to be completed; the control module sends a signal to close the first NTP control valve and the second NTP control valve, open the first exhaust control valve and The second exhaust control valve, closes the NTP injection system.

Preferably, the step 1 also includes determining the optimum temperature range for the reaction of active gas and carbon deposits inside the DPF through experiments to obtain the optimum regeneration temperature upper limit T _c and the optimum regeneration temperature lower limit T _f , and The optimal regeneration temperature upper limit T _c and the optimal regeneration temperature lower limit T _f are stored in the control module; when online regeneration and shutdown regeneration are performed, the temperature drop trend of the corresponding DPF is monitored by the DPF temperature sensor to judge Whether the timing of regeneration is reached; when the control module detects that T ₁ and/or T ₂ is less than the optimal regeneration temperature upper limit _Tc , regeneration will start; during the regeneration process, when T ₁ and/or T ₂ is less than the optimum When the regeneration temperature lower limit _Tf , the control module starts the first electric heating layer and/or the second electric heating layer to heat the first DPF and/or the second DPF, so that the temperature of the first DPF and/or the second DPF is kept at the minimum within the optimal regeneration temperature range; after the regeneration is completed, the first electric heating layer and/or the second electric heating layer stop heating.

Preferably, the control module adjusts the air supply rate to 10L/min through a mass flow controller; the power supply voltage of the NTP injection system is 17-20kV, and the discharge frequency is 7-10kHz.

Beneficial effects of the present invention: 1) The double DPF system can be alternately regenerated during the operation of the diesel engine, which solves the problem that the NTP utilization rate decreases due to excessive exhaust flow in online regeneration; 2) The thermoelectric conversion device can effectively control the DPF The temperature is within the optimum regeneration temperature range, and no external power supply is required during the operation of the diesel engine.

All DPF regeneration processes are carried out after the corresponding exhaust control valve is closed to avoid excessive exhaust flow and affect the reaction effect of NTP and carbon deposits inside the DPF; all DPF regeneration processes are carried out within the optimum regeneration temperature range , which greatly improves the utilization rate of NTP; therefore, the present invention adopts a regeneration strategy combining online and offline, which improves regeneration efficiency and effectively saves energy.

Description of drawings

Fig. 1 is a schematic structural diagram of the DPF regeneration system of the present invention.

Fig. 2 is a schematic diagram of the structure of the NTP injection system of the present invention.

Fig. 3 is a schematic diagram of a double DPF system equipped with an NTP injection system and a thermoelectric conversion device according to the present invention.

Fig. 4 is a schematic diagram of exemplary steps of the DPF regeneration control method of the present invention.

in:

001: Diesel engine 002: Air filter 003: Intake pipeline

004: exhaust pipe 100: NTP injection system 200: double DPF system

300: Thermoelectric conversion device 400: Control module 101: NTP generator

102: Air supply fan 103: Mass flow controller 104: Air inlet

105: Gas outlet 106: Fine barbed wire outer electrode 107: Quartz tube

108: Electrode in stainless steel tube 109: Oscilloscope 110: Power supply

111: Generator water inlet 112: Generator water outlet 113: Injection pipeline

114: First NTP control valve 115: Second NTP control valve 116: First nozzle

117: Second nozzle 201: First DPF 202: Second DPF

203: First exhaust control valve 204: Second exhaust control valve 301: First electric heating layer

302: Second electric heating layer 401: First differential pressure sensor 402: Second differential pressure sensor

403: First temperature sensor 404: Second temperature sensor

detailed description

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

As shown in Figure 1, the DPF regeneration system of the present invention includes an NTP injection system 100, a double DPF system 200, a thermoelectric conversion device 300 and a control module 400, and the thermoelectric conversion device 300 is installed in the front row of the dual DPF system 200 On the gas pipeline, the NTP injection system 100 , the dual DPF system 200 and the thermoelectric conversion device 300 are all connected to the control module 400 .

As shown in FIG. 2 , the NTP injection system 100 includes an NTP generator 101 , an air supply fan 102 , a mass flow controller 103 , an oscilloscope 109 , a power supply 110 , an injection pipeline 113 , and a nozzle. The NTP generator 101 is a dielectric barrier discharge type, comprising a fine barbed wire outer electrode 106, a quartz tube 107 and a stainless steel tube inner electrode 108; the thin barbed wire outer electrode 106 is wrapped in the outer wall of the quartz tube 107, and the stainless steel tube inner electrode 108 is installed on Inside the quartz tube 107, a discharge gap with a circular section is formed between the stainless steel tube inner electrode 108 and the quartz tube 107, and the thin barbed wire outer electrode 106 is a discharge area. The power supply 110 is used to provide trigger power to the NTP generator 101 , and the oscilloscope 109 is used to record different discharge conditions of the power supply 110 .

The air supply fan 102 is connected to the inlet end 104 of the NTP generator 101 through a pipeline equipped with a mass flow controller 103, and the gas outlet end 105 of the NTP generator 101 is connected to the nozzle through an injection pipeline 113, and the injection The rear section of the pipeline 113 is divided into two injection branches. The first NTP control valve 114 and the second NTP control valve 115 are respectively installed on the two injection branches, and the end of the injection branch where the first NTP control valve 114 is installed It is connected to the first nozzle 116, and the end of the injection branch line installed with the second NTP control valve 115 is connected to the second nozzle 117. The NTP gas source enters the discharge gap through the inlet port 104, and discharges through the discharge area to form NTP active gas. The active gas enters the injection pipeline 113 through the NTP generator outlet port 105, and is ejected from the nozzle to participate in the regeneration of the DPF.

As shown in FIG. 3 , the dual DPF system 200 includes a first DPF 201 and a second DPF 202, the first DPF 201 and the second DPF 202 are connected in parallel through an exhaust branch, and the front-end row of the first DPF 201 A first exhaust control valve 203 is installed on the gas branch, a first differential pressure sensor 401 is installed on the exhaust branch of the first DPF 201, and a first temperature sensor 403 is installed downstream of the first DPF 201; A second exhaust control valve 204 is installed on the exhaust branch at the front end of the second DPF 202 , a second differential pressure sensor 402 is installed on the exhaust branch of the second DPF 202 , and the downstream of the second DPF 202 is further A second temperature sensor 404 is installed; the shells of the first DPF 201 and the second DPF 202 are wrapped with the first electric heating layer 301 and the second electric heating layer 302 respectively, and the thermoelectric conversion device 300 selectively uses waste heat to convert The electric energy and the storage battery provide energy for the first electric heating layer 301 and the second electric heating layer 302, so that the DPF is at an optimal regeneration temperature. The first electric heating layer 301 and the second electric heating layer 302 are powered by the vehicle battery when the diesel engine is stopped.

The first nozzle 116 and the second nozzle 117 in the NTP injection system 100 are respectively installed at the inlets of the first DPF 201 and the second DPF 202, and the thermoelectric conversion device 300 is installed at the front exhaust pipe of the double DPF system 200 On the road, 100 mm away from the front faces of the first DPF 201 and the second DPF 202; the first NTP control valve 114, the second NTP control valve 115, the first exhaust control valve 203, the second exhaust control valve 204, The first differential pressure sensor 401 , the second differential pressure sensor 402 , the first temperature sensor 403 , and the second temperature sensor 404 are all connected to the control module 400 .

The first NTP control valve 114 and the second NTP control valve 115 are both closed when the NTP injection system 100 is shut down, and the first exhaust control valve 203 and the second exhaust control valve 204 are both closed when the diesel engine is running normally. is in an open state; the first exhaust control valve 203 is in a closed state during the regeneration of the first DPF 201, and the second exhaust control valve 203 is in a closed state during the regeneration of the second DPF 202; the first The exhaust control valve 203 and the second exhaust control valve 204 cannot be closed at the same time when the diesel engine is running. When the first DPF 201 and the second DPF 202 meet the regeneration requirements at the same time, the first exhaust control valve 203 and the second exhaust The control valve 204 is opened at the same time, and the DPF is regenerated off-line after the diesel engine stops.

Figure 4 shows the flow chart of DPF regeneration; before use, a calibration test should be performed on the dual DPF system 200 to determine the corresponding DPF pressure difference upper limit threshold ΔP _c of the diesel engine under different working conditions, and to mark the regeneration target of DPF regeneration completion Pressure difference ΔP ₀ ; determine the optimal temperature range for the reaction of active gas and carbon deposit inside the DPF through experiments, and obtain the upper limit of the optimal regeneration temperature T _c and the lower limit of the optimal regeneration temperature T _f . The pressure difference upper limit threshold ΔP _c and regeneration target pressure difference ΔP ₀ are stored in the control module 400 . The optimal regeneration temperature upper limit T _c and the optimal regeneration temperature lower limit T _f are stored in the control module 400 .

Once the vehicle is started, the control module 400 monitors the differential pressures ΔP ₁ and ΔP ₂ at the front and rear ends of the first DPF 201 and the second DPF 202 through the first differential pressure sensor 401 and the second differential pressure sensor 402 , which are compared with the pre-stored pressure in the control module 400 . Compare with the difference upper limit threshold ΔP _c to determine whether regeneration is required;

When the control module 400 detects that the pressure difference ΔP ₁ between the front and back ends of the first DPF 201 is greater than the upper limit threshold ΔPc of the pressure difference and the pressure difference ΔP ₂ between the front and rear ends of the second DPF 202 is smaller than the upper limit threshold ΔP _c of the pressure difference, it is considered that the first DPF 201 needs to be regenerated; If the second exhaust control valve 204 is in the closed state at this time, then open the second exhaust control valve 204 and re-determine; if the second exhaust control valve 204 is in the open state at this time, then close the first exhaust control valve 203 , to perform online regeneration, the control module sends a signal to start the NTP injection system 100, opens the first NTP control valve 114, injects active gas from the front end of the first DPF 201, and regenerates the first DPF 201; the control module 400 monitors the first When the pressure difference ΔP ₁ between the front and back ends of the DPF 201 is less than the regeneration target pressure difference ΔP ₀ , the regeneration is considered to be completed; the control module sends a signal to close the first NTP control valve 114, open the first exhaust control valve 203, and close the NTP injection system 100;

When the control module 400 detects that the pressure difference ΔP ₂ between the front and rear ends of the second DPF 202 is greater than the upper limit threshold ΔP _c of the pressure difference and the pressure difference ΔP ₁ between the front and rear ends of the first DPF 201 is smaller than the upper limit threshold ΔP _c of the pressure difference, it is considered that the second DPF 202 needs to be regenerated ; If the first exhaust control valve 203 is in the closed state at this time, then open the first exhaust control valve 203 and re-determine; if the first exhaust control valve 203 is in the open state at this time, then close the second exhaust control valve 204, perform online regeneration, the control module sends a signal to start the NTP injection system 100, opens the second NTP control valve 115, injects active gas from the front end of the second DPF 202, and regenerates the second DPF 202; the control module 400 monitors the first 2. When the pressure difference ΔP ₂ between the front and rear ends of the DPF 202 is less than the regeneration target pressure difference ΔP ₀ , the regeneration is considered to be completed; the control module sends a signal to close the second NTP control valve 115, open the second exhaust control valve 204, and close the NTP injection system 100;

When the control module 400 detects that the pressure difference between the front and rear ends of the first DPF 201 and the second DPF 202 is greater than the pressure difference upper limit threshold ΔP _c , it is considered that both need to be regenerated; at this time, in order to ensure smooth exhaust, the control module 400 controls the first The first exhaust control valve 203 and the second exhaust control valve 204 are kept open. After receiving the shutdown signal of the diesel engine, the first exhaust control valve 203 and the second exhaust control valve 204 are closed to perform shutdown regeneration, and the control module sends out a signal Turn on the NTP injection system 100, open the first NTP control valve 114 and the second NTP control valve 115, inject active gas into the front end of the first DPF 201 and the second DPF 202 respectively, and regenerate the first DPF 201 and the second DPF 202; When the control module 400 monitors that the pressure difference ΔP ₁ between the front and rear ends of the first DPF 201 and the pressure difference ΔP ₂ between the front and rear ends of the second DPF 202 are both less than the regeneration target pressure difference ΔP ₀ , the regeneration is considered complete; the control module sends a signal to close the first NTP The control valve 114 and the second NTP control valve 115 open the first exhaust control valve 203 and the second exhaust control valve 204 and close the NTP injection system 100 .

When online regeneration and shutdown regeneration are performed, the DPF temperature sensor starts to monitor the temperature drop trend of the corresponding DPF to judge whether the regeneration opportunity is reached _; when the control module 400 detects that T1 and/or T2 are less _than the upper limit of the optimal regeneration temperature value _Tc , start to regenerate, during regeneration, when T1 and/or T2 is less _than the optimal regeneration temperature lower limit _Tf , the control module starts the first electric heating layer 301 and/or the _second electric heating layer 301 The heating layer 302 heats the first DPF 201 and/or the second DPF 202, so that the temperature of the first DPF 201 and/or the second DPF 202 is kept within the optimal regeneration temperature range; after the regeneration is completed, the first electric heating layer 301 and/or The second electric heating layer 302 stops heating.

During shutdown and regeneration, the first electric heating layer 301 and the second electric heating layer 302 are powered by the vehicle battery. During online regeneration, the first electric heating layer 301 and the second electric heating layer 302 are powered by the thermoelectric conversion device 300 installed on the front exhaust pipeline of the double DPF system 200 .

During the regeneration process, the control module adjusts the air supply rate to 10L/min through the mass flow controller 103; the voltage of the NTP injection system power supply 110 is 17-20kV, and the discharge frequency is 7-10kHz.

All DPF regeneration processes are carried out after the corresponding exhaust control valve is closed to avoid excessive exhaust flow and affect the reaction effect of NTP and carbon deposits inside the DPF; all DPF regeneration processes are carried out within the optimum regeneration temperature range , which greatly improves the utilization rate of NTP; therefore, the present invention adopts a regeneration strategy combining online and offline, which improves regeneration efficiency and effectively saves energy.

The described embodiment is a preferred implementation of the present invention, but the present invention is not limited to the above-mentioned implementation, without departing from the essence of the present invention, any obvious improvement, replacement or modification that those skilled in the art can make Modifications all belong to the protection scope of the present invention.

Claims (10)

1. A kind of DPF regeneration system is characterized in that, comprises NTP injection system (100), double DPF system (200) and control module (400); Described NTP injection system (100) comprises NTP generator (101), supply Air fan (102), mass flow controller (103), oscilloscope (109), power supply (110), injection pipeline (113), nozzle; described air supply fan (102) is equipped with mass flow controller (103 ) pipeline is connected with the inlet end (104) of the NTP generator (101), and the outlet end (105) of the NTP generator (101) is connected with the nozzle through the injection pipeline (113), and the injection pipeline ( 113) The rear section is divided into two injection branches, the first NTP control valve (114) and the second NTP control valve (115) are respectively installed on the two injection branches, and the first NTP control valve (114) is installed The end of the injection branch is connected to the first nozzle (116), and the second NTP control valve (115) is installed at the end of the injection branch to connect the second nozzle (117); The dual DPF system (200) includes a first DPF (201) and a second DPF (202), the first DPF (201) and the second DPF (202) are connected in parallel through an exhaust branch, and the first A first exhaust control valve (203) is installed on the exhaust branch at the front end of the DPF (201), and a first differential pressure sensor (401) is installed on the exhaust branch of the first DPF (201); the second The exhaust branch of the DPF (202) is equipped with a second exhaust control valve (204), and the upstream and downstream of the second DPF (202) are respectively equipped with second differential pressure sensors (402). The first nozzle (116) and the second nozzle (117) in the NTP injection system (100) are respectively installed at the inlets of the first DPF (201) and the second DPF (202), and the first NTP control valve (114), second NTP control valve (115), first exhaust control valve (203), second exhaust control valve (204), first differential pressure sensor (401), second differential pressure sensor (402) All are connected with the control module (400); The control module (400) pre-stores the DPF pressure difference upper limit threshold ΔP _c , the target pressure difference ΔP ₀ marking the completion of DPF regeneration, and collects the pressure difference ΔP ₁ at both ends of the first DPF (201) and/or the second DPF ( 202) the pressure difference ΔP ₂ at both ends, according to the pre-stored DPF pressure difference upper limit threshold ΔP _c and the real-time detected pressure difference ΔP ₁ at both ends of the first DPF (201) and/or the pressure difference ΔP ₂ at both ends of the second DPF (202) Determine whether DPF regeneration is required; and control the opening and closing of the first NTP control valve (114), the second NTP control valve (115), the first exhaust control valve (203), and the second exhaust control valve (204) And the opening and closing of the NTP injection system (100) realizes online regeneration or shutdown regeneration of the first DPF (201) and/or the second DPF (202). 2. The DPF regeneration system according to claim 1, characterized in that a first temperature sensor (403) and a second temperature sensor are respectively installed downstream of the first DPF (201) and the second DPF (202) (404), the shells of the first DPF (201) and the second DPF (202) are respectively wrapped with the first electric heating layer (301) and the second electric heating layer (302) connected to the power supply, the first Both the temperature sensor (403) and the second temperature sensor (404) are connected to the control module; The optimal temperature range T _f ~ T _c for regeneration is pre-stored in the control module, and the control module (400) is also based on the temperature T 1 of the first DPF (201) and the temperature T ₂ of the _second DPF (202) , during on-line regeneration or shutdown regeneration, control T ₁ and/or T ₂ to be within the optimal temperature range T _f ~ T _c for regeneration. 3. DPF regeneration system according to claim 1, is characterized in that, also comprises thermoelectric conversion device (300), and described thermoelectric conversion device (300) is installed on the front-end exhaust pipeline of double DPF system (200), is The first electric heating layer (301) and the second electric heating layer (302) provide electric energy. 4. The DPF regeneration system according to claim 1, characterized in that, the installation positions of the first nozzle (116) and the second nozzle (117) are respectively far from the first DPF (201) and the second DPF (202) The front face of the 100mm. 5. The DPF regeneration system according to claim 1, characterized in that, the NTP injection system (100) adopts a water-cooled cooling system, and the cooling water enters the inside of the NTP generator (101) from the water inlet (111) and passes through the water outlet (112) discharge; the voltage and frequency of the power supply (110) of the NTP injection system (100) are adjustable. 6. The DPF regeneration system according to claim 1, characterized in that, the NTP generator (101) is a dielectric barrier discharge type, comprising a fine wire mesh outer electrode (106), a quartz tube (107) and a stainless steel tube inner electrode ( 108); the fine barbed wire outer electrode (106) is wrapped in the outer wall of the quartz tube (107), the stainless steel tube inner electrode (108) is installed inside the quartz tube (107), and the stainless steel tube inner electrode (108) and the quartz tube ( 107) form a discharge gap with a ring-shaped section, and the outer electrode (106) of the fine wire mesh is a discharge area. 7. The DPF regeneration system according to claim 1, characterized in that the first electric heating layer (301) and the second electric heating layer (302) are powered by an on-board battery when the diesel engine is stopped. 8. The DPF regeneration control method of the DPF regeneration system of claim 1, is characterized in that, comprises the steps: Step 1: Carry out a calibration test on the dual DPF system (200), determine the corresponding DPF pressure difference upper limit threshold ΔP _c under different working conditions of the diesel engine, and mark the regeneration target pressure difference ΔP ₀ after DPF regeneration is completed; set the pressure difference upper limit threshold ΔP _c , The regeneration target differential pressure ΔP ₀ is stored in the control module (400); Step 2: The control module (400) monitors the differential pressures ΔP ₁ and ΔP ₂ at the front and rear ends of the first DPF (201) and the second DPF (202) through the first differential pressure sensor (401) and the second differential pressure sensor (402) , compared with the pre-stored pressure difference upper limit threshold ΔP _c in the control module (400), to determine whether regeneration is required; When the control module (400) detects that the pressure difference ΔP ₁ between the front and back of the first DPF (201) is greater than the upper limit threshold ΔPc of the pressure difference and the pressure difference ΔP ₂ between the front and rear ends of the second DPF (202) is smaller than the upper limit threshold ΔP _c of the pressure difference, it is considered that the first A DPF (201) needs to be regenerated; if the second exhaust control valve (204) is in the closed state at this time, then open the second exhaust control valve (204) and re-determine; if the second exhaust control valve ( 204) is in the open state, then close the first exhaust control valve (203) to perform online regeneration, the control module sends a signal to open the NTP injection system (100), open the first NTP control valve (114), and discharge the active gas from the first The front end of the DPF (201) is sprayed to regenerate the first DPF (201); when the control module (400) monitors that the pressure difference ΔP ₁ between the front and rear ends of the first DPF (201) is less than the regeneration target pressure difference ΔP ₀ , the regeneration is considered complete ; The control module sends a signal to close the first NTP control valve (114), open the first exhaust control valve (203), and close the NTP injection system (100); When the control module (400) detects that the pressure difference ΔP ₂ between the front and rear of the second DPF (202) is greater than the upper limit threshold ΔP _c of the pressure difference and the pressure difference ΔP ₁ between the front and rear ends of the first DPF (201) is less than the upper limit threshold ΔP _c of the pressure difference, it is considered The second DPF (202) needs to be regenerated; if the first exhaust control valve (203) is closed at this time, open the first exhaust control valve (203) and re-determine; if the first exhaust control valve (203) is in the open state, then close the second exhaust control valve (204), carry out on-line regeneration, the control module sends a signal to open the NTP injection system (100), open the second NTP control valve (115), and activate the gas from the first The front end of the second DPF (202) is sprayed to regenerate the second DPF (202); when the control module (400) monitors that the pressure difference ΔP ₂ between the front and rear ends of the second DPF (202) is less than the regeneration target pressure difference ΔP ₀ , it is considered to be regenerated Complete; the control module sends a signal to close the second NTP control valve (115), open the second exhaust control valve (204), and close the NTP injection system (100); When the control module (400) detects that the pressure difference between the front and rear ends of the first DPF (201) and the second DPF (202) is greater than the pressure difference upper limit threshold ΔP _c , it is considered that both need to be regenerated; at this time, to ensure smooth exhaust , the control module (400) controls the first exhaust control valve (203) and the second exhaust control valve (204) to keep open, and closes the first exhaust control valve (203) and the second exhaust control valve (203) and the second The exhaust control valve (204) is used for shutdown regeneration, the control module sends a signal to open the NTP injection system (100), opens the first NTP control valve (114) and the second NTP control valve (115), and injects active gas into the first NTP control valve (115) respectively. The front end of a DPF (201) and the second DPF (202) regenerate the first DPF (201) and the second DPF (202); when the control module (400) monitors the pressure difference ΔP between the front and rear ends of the first DPF (201) _1. When the pressure difference ΔP ₂ at the front and rear ends of the second DPF (202) is less than the regeneration target pressure difference ΔP ₀ , it is considered that the regeneration is completed; the control module sends a signal to close the first NTP control valve (114), the second NTP control valve (115 ), open the first exhaust control valve (203) and the second exhaust control valve (204), and close the NTP injection system (100). 9. The DPF regeneration control method according to claim 8, characterized in that, said step 1 also includes determining the optimum temperature range for the reaction of active gas and carbon deposition inside the DPF through experiments to obtain the optimum regeneration temperature upper limit T _c and the optimal regeneration temperature lower limit T _f , and store the optimal regeneration temperature upper limit T _c and the optimal regeneration temperature lower limit T _f in the control module (400); when performing online regeneration and shutdown regeneration When the DPF temperature sensor starts to monitor the temperature drop trend of the corresponding DPF to judge whether the regeneration opportunity is reached _; when the control module (400) detects that T1 and/or T2 are less _than the optimal regeneration temperature upper limit _Tc , Start regeneration, and during regeneration, when T1 and/or T2 are less _than the optimum regeneration temperature lower limit _Tf , the control module starts the first electric heating layer (301) and/or the _second electric heating layer ( 302) heating the first DPF (201) and/or the second DPF (202), so that the temperature of the first DPF (201) and/or the second DPF (202) is kept within the optimum regeneration temperature range; after the regeneration is completed, the first The electric heating layer (301) and/or the second electric heating layer (302) stop heating. 10. The DPF regeneration control method according to claim 8, characterized in that the control module adjusts the air supply rate to 10L/min through a mass flow controller (103); the voltage of the NTP injection system power supply (110) is 17-20kV, The discharge frequency is 7~10kHz.