KR100789166B1 - Learning adaptive control method and simultaneous reduction system on exhaust gas and particulate matter of diesel vehicle for retrofit - Google Patents

Abstract

The present invention relates to a technology for purifying exhaust gas by installing a diesel engine and modifying a diesel vehicle in operation. Particularly, when the diesel engine is installed in addition to a diesel vehicle currently in operation, particulate matter (PM) is discharged from the diesel engine. Matters) and to provide a method for the exhaust gas purification of diesel fuel vehicles, which is particularly effective in simultaneously reducing nitrogen oxides (NOx), and a diesel engine modified exhaust gas purification system designed to be suitable for implementing the method.

According to the present invention, by adding a complex system composed of a catalytic particulate matter removal filter (DPF) and a cooled exhaust gas recirculation device (Cooled EGR) to the engine of the existing diesel engine running, By reducing particulate matter (PM) and nitrogen oxide simultaneously, the reduction target value can be achieved stably.

In addition, according to the present invention, it is possible to generate a control map for the reduction of nitrogen oxides by applying a self-learning adaptive control method and to realize the optimum control, thereby obtaining a control map as in the conventional method. Many required tests and the enormous cost can be saved, and the self-learning adaptation control prevents the emission reduction from falling even when the vehicle is aging.

Diesel, particulate matter (PM), diesel particulate removal filter (IDF), exhaust gas recirculation (EGR), learning adaptation control, retrofit, control map, learning control

Description

Learning adaptive control method and simultaneous reduction system on exhaust gas and particulate matter of diesel vehicle for retrofit}

1 is a block diagram showing the configuration of a diesel engine having a diesel engine modified exhaust gas purification system according to an embodiment of the present invention.

2 is a control block diagram for control of the diesel engine retrofit exhaust gas purification system of FIG.

3 is a data processing sequence diagram of an EGR control system for controlling a diesel engine modified exhaust gas purification system.
Figure 4 is a reference diagram briefly showing the configuration of the diesel engine of the past production vehicle to be subjected to the modification of the present invention

* Explanation of symbols for the main parts of the drawings

10, 210: engine, 15, 215: intake manifold, 20, 220: exhaust manifold, 25, 225: turbocharger intake, 30, 230: turbocharger exhaust, 35, 235: intercooler, 40: EGR valve, 50 : EGR cooler outlet temperature sensor, 55: EGR controller, 60: engine coolant temperature detector, 65: particulate matter removal filter (DPF), 70: bypass valve, 75: DPF shear temperature detector, 76: DPF shear pressure Detection device, 80: DPF rear end temperature detection device, 85: NOx detection device, 90: EGR cooler, 95: EGR cooling pump

The present invention relates to a technology for purifying exhaust gas by retrofitting a past production diesel vehicle in operation with a diesel engine, in particular, in addition to the past production diesel vehicle currently in operation, particulate matter discharged from the diesel engine ( It is to provide an exhaust gas purification system and an exhaust gas purification method for diesel vehicle modification, which are particularly effective in reducing PM (Particulate Matters) and nitrogen oxides (NOx).

Recently, as the harmfulness of human body caused by nitrogen oxides (NOx) and particulate matter (PM) emitted from diesel vehicles has been proved, regulations on diesel exhaust vehicles have been tightened. Accordingly, particulate matter (PM) and nitrogen oxides (NOx) have been tightened. In the past, where regulatory standards for stiffening standards were not strict, modifications to current vehicles are inevitable.
In Tokyo, Japan, the NOx and PM have been enforced to restrict the operation of diesel vehicles that do not have post-treatment devices.The existing vehicles are equipped with particulate matter filtering devices and nitrogen oxide abatement devices. In other words, the company is moving a service area outside the regulation.
In Europe, regulatory standards for particulate matter and nitrogen oxides are established, but the regulatory standards are strengthened annually from 2000 to 2008. The following table shows the regulatory standards for vehicle emissions that are carried out annually in Europe.
division EURO-2 (K2000) EURO-3 (K2003) EURO-4 (K2006) EURO-5 (K2008) PM (g / Kwh) 7.0 5.0 3.5 2.0 NOx (g / Kwh) 0.15 0.1 0.02 0.02

Particulate matter (PM) among the harmful emissions of diesel vehicles is already mass-produced and installed as a problem that can be solved by a catalytic particulate filter (DPF) that does not interfere with the operation of existing vehicles.
In order to reduce NOx, there are many problems to be solved in the technical and social areas, but long catalysts and SCR devices have been used. On the other hand, in recent years, the exhaust gas recirculation device (EGR: Exausted Gas Recycle) has been proven to be reliable in gasoline and diesel vehicles, showing a great effect in reducing nitrogen oxides.
Accordingly, the trend is that recently produced cars are produced with devices such as DPF or EGR.
On the other hand, after it is known that reducing the emission of particulate matter and nitrogen oxide is effective in improving the air environment in the city, the demand for vehicle modification is increasing for the regulation of existing vehicles. The government is also seeking to provide government subsidies for retrofitting existing diesel vehicles.
In order to apply the proven EGR system as a retrofit device for an existing vehicle, it is necessary to control the appropriate EGR flow rate, which requires a control map of the EGR valve for each vehicle.

In order to obtain the control map of the EGR valve, the engine or vehicle is installed in the engine dynamometer or chassis dynamometer, which requires a lot of test and analysis. It is an impossible situation.

Therefore, in order to efficiently apply the combined system of DPF and EGR that can stably reduce NOx and PM emitted from existing diesel vehicles, the EGR control map adapted to each vehicle can be generated by itself for optimal control. There is a need for a learning adaptation control method that can be performed.

The EGR amount varies depending on the engine condition and changes according to the aging of the engine. It takes a great deal of time and money to obtain the optimal EGR control map. In particular, it is very difficult to secure an optimal EGR control map for emission reduction in existing mechanical diesel engines in operation. Existing mechanical diesel engines are aging, and their characteristics are changed for each engine, and they are transformed into a different form from the EGR control map of the new engine. For this reason, there is a limit to tightening exhaust gas regulations for existing mechanical diesel engines so that new purification systems can be attached.

According to the conventional research, Korean Patent Laid-Open Publication No. 2003-0049685 proposed an EGR control device for a diesel engine and a method of controlling the EGR amount using a driving pump by the method, but the portion of the EGR control amount is insufficient, and the Republic of Korea Patent Publication No. 2003-0049685 -0080657 proposes a control method for correcting the EGR valve control at low temperatures, in accordance with the engine's running pattern and driving conditions, but partially compensates for the EGR control map of the engine. The existing patent as described above is a method of controlling based on the EGR control map of the engine, and the EGR control map is obtained through a long-term experiment, and the cost of this is enormous.

Also, US Patent No. 5,927,075 is a patent on EGR control considering fuel efficiency and system performance. However, in this patent, the EGR control is performed in the presence of the EGR map, and thus, it is difficult to apply to the existing diesel engine whose EGR map is unknown because there is no emission reduction device. It is difficult to apply to existing vehicles. In addition, US Pat. No. 5,520,161, which is a similar patent, has grasped the characteristics of the engine sufficiently to partially correct the engine according to various engine conditions based on various EGR maps.
There is no technology developed to regulate the exhaust gas purification of mechanical diesel engines currently in operation, and the existing technology is required because the EGR valve control map acquired through long-term tests in the engine dynamometer or chassis dynamometer is essential. If applied, it is difficult to retrofit the vehicle.

The present invention provides an exhaust gas purification system and an exhaust gas purification system for diesel engine modification, which can stably realize simultaneous reduction of particulate matter (PM) and nitrogen oxides (NOx) discharged by simply additionally installing the diesel fuel vehicle in the past. It is a technical task to provide a method.
In addition, the present invention provides an exhaust gas purification system for retrofitting a diesel engine equipped with a catalytic DPF, a cooling EGR complex system and a control device for controlling the same, wherein the control map for the above control device is operated within a minimum taming driving period. Another technical challenge is to provide a technology that allows it to generate itself.

As a means for realizing the above-described technical problem, the present invention is a diesel engine modified exhaust gas purification system that can be additionally mounted to the diesel engine of the past production vehicle in operation to enable the exhaust gas purification, the exhaust gas from the diesel engine It comprises a particulate matter removal filter 65 for removing particulate matter (PM) contained in the exhaust gas, an EGR cooling device 90, an EGR cooling pump 95, and an EGR valve 40 for controlling the amount of recycled exhaust gas. On the basis of the monitoring results from the cooled exhaust gas recirculation device (Cooled EGR) to reduce the nitrogen oxides (NOx) contained in the exhaust gas passing through the particulate matter removal filter, and various sensors installed in the vehicle and engine An EGR control map is generated so that particulate matter and nitrogen oxide contained in exhaust gas are below the regulatory standard, and accordingly, the EGR valve 40 and the EGR cooling pump It provides a diesel engine rebuilt exhaust gas purification system comprising the EGR controller 55 for controlling (95).
In addition, according to the present invention, it is preferable that the EGR controller has a self-learning function for automatically generating an EGR control map based on the type and year information of the engine input during the remodeling process.
In addition, according to the present invention, it shows the calculated NOx reduction value, the back pressure of the DPF and the accumulation of soot and non-combustible ash, together with the EGR valve opening amount and the operating state of the EGR cooler, It also includes an EGR display unit 120 for monitoring and warning signal if exceeded.
Further, according to the present invention, when the particulate matter removing filter is clogged, it is more preferable to include a bypass means for bypassing the particulate matter removing filter 65 so as not to pass.
According to another aspect of the invention, in the exhaust gas purification method for the diesel engine of the past production vehicle in operation, the particulate matter removal filter 65 for removing particulate matter (PM) contained in the exhaust gas discharged from the diesel engine. And an EGR cooling device 90, an EGR cooling pump 95, and an EGR valve 40 for controlling the amount of recycled exhaust gas, and the nitrogen oxides (NOx) contained in the exhaust gas passing through the particulate matter removal filter. A first step of additionally equipping an exhaust gas purification system comprising a cooled cooled exhaust gas recirculation device (Cooled EGR) and an EGR controller (55) for controlling the EGR valve (40) and the EGR cooling pump (95). The engine of the vehicle is rapidly accelerated under no load, and the engine speed and the accelerator pedal opening range are detected and the particulate matter and nitrogen oxide contained in the exhaust gas are below the regulatory standard based on the engine speed and the accelerator pedal opening range. Provides an exhaust gas purifying method of diesel engine vehicles group being operated according to claim characterized in that it comprises a step of generating an EGR control map for controlling the EGR valve 40 and the EGR coolant pump (95).
In addition, according to the present invention, the second step of generating the EGR control map is the step of inputting the type and year information of the engine and automatically generating the EGR control map of the initial state through the self-learning based on the engine, and the engine aging It is desirable to include an optimization step that continuously reflects control characteristics that change as it proceeds.
Further, according to the present invention, the second step of generating the EGR control map is a process of optimizing the EGR control map, including an EGR control and sensitivity analysis step (S600) and a control map optimization calculation step (S500). More preferably, the learning control is performed until the control map converges.
DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram illustrating the configuration of a diesel engine retrofit exhaust gas purification system according to the present invention.
As shown in FIG. 1, the diesel engine retrofit exhaust gas purification system according to the present invention has a conventional diesel engine configuration shown in FIG. 4, which simultaneously reduces particulate matter (PM) and nitrogen oxides emitted from a diesel vehicle. A catalytic particulate removal filter (DPF), a cooled exhaust gas recirculation device (Cooled EGR), and an EGR controller for controlling them are added.

The engine speed detection device 105 detects the engine speed, and the accelerator pedal opening degree detection device 110 can infer the torque of the engine and calculate the engine output from the engine speed and the torque. In addition, the vehicle speed detecting apparatus 100 is a device for detecting a traveling speed of the vehicle, and the engine oil temperature detecting apparatus 115 is a signal for determining a warm-up state of the engine. In this condition, all control and control map generation process is performed.

Regarding the particulate matter removal filter (DPF), a DPF front end exhaust gas temperature detector 75, a DPF rear end exhaust gas temperature detector 80, and a DPF front end pressure detector 76 are included. The operating condition of, the soot collection and the accumulation of non-combustible ash can be calculated.

2 shows an EGR control device / learning device 50 for generating an EGR control signal based on signals input from various detection devices, which have a self-learning function and an EGR valve control unit which is a driving device. 40, the bypass valve control unit 70, the EGR controller 95 and the EGR display unit 120 is controlled.

The EGR valve controller 40 and the EGR controller 55 control the EGR flow rate and the cooling temperature, and control the EGR flow rate according to the nitrogen oxide reduction target amount, and the regeneration temperature of the DPF is excessively increased according to the regeneration situation of the DPF. If the flow rate of EGR Cooler is increased, the regeneration temperature of DPF is low. If the regeneration temperature is low, the EGR Cooler coolant flows to reduce the flow rate.

The bypass valve control unit 70 operates to open with a maintenance warning light when the back pressure rises above a prescribed value due to damage or excessive blockage of the DPF to adversely affect the output of the engine.

The EGR display unit 120, which emits an EGR operating state and a monitoring / warning signal, notifies the EGR valve opening amount, whether the bypass valve is opened or closed, and the operating state of the EGR cooler, and displays the NOx reduction calculated therefrom. It consists of a device that shows the accumulation of soot and non-combustible ash, and emits a monitoring and warning signal when the specified threshold is exceeded.

It will be described with reference to Figure 3 attached to the embodiment according to the method for reducing the smoke of the diesel engine having the above configuration.

After installing the EGR on the diesel vehicle for the first time, the EGR installer initializes the detection unit, the EGR control unit 50, and the control unit 120, 40, 70, 55 (S200), and the type and year of the engine mounted on the vehicle. Is input (S205).

After that, if the engine is run in IDLE and warmed up sufficiently, the engine is operated under free acceleration to determine the grid of the control map by setting the minimum maximum value of the engine speed and the accelerator pedal opening (S210). )do.

After that, the driver can operate the same as before the EGR is installed, and when the engine is sufficiently warmed up (S215), the vehicle load state detection and map generation (S220) are performed while the control unit is not operated, and the DPF monitoring is performed. Part S225 is performed.

After that, if the generated control map is in sufficient convergence condition, the EGR control and sensitivity analysis unit (S600) controls the EGR valve and the EGR cooler, and analyzes the sensitivity from the NOx change according to the control to achieve the NOx reduction amount. Transfer to the calculation unit (S500). The control map optimization calculation unit S500 calculates an optimum control amount at each control point to satisfy the NOx reduction rate of the EGR system by using the sensitivity of the NOx change amount. The restriction condition at this time minimizes the deterioration of fuel economy within a given NOx reduction target rate, generates an optimum control map that can minimize an increase in cooling capacity, and transmits the generated EGR control map to the EGR control unit S600 to EGR. Learning control continues until the system is controlled and the optimal EGR control map is converged. Through the above process, the EGR control map is generated without testing on the engine dynamometer or the chassis dynamometer.

By providing the present invention having the configuration as described above, by adding a complex system consisting of a catalytic particulate matter removal filter (DPF) and a cooled exhaust gas recirculation device (Cooled EGR) to the engine of the existing production diesel vehicle in operation in the past At the same time, particulate matter (PM) and nitrogen oxides emitted from diesel engine vehicles are reduced at the same time, thereby achieving stable reduction targets.
In addition, according to the present invention, it is possible to generate a control map for the reduction of nitrogen oxides by applying a self-learning adaptive control method and to realize the optimum control, thereby obtaining a control map as in the conventional method. Many required tests and the enormous cost can be saved, and the self-learning adaptation control prevents the emission reduction from falling even when the vehicle is aging.

Claims (7)

In the diesel engine modified exhaust gas purification system that can be further mounted on the diesel engine of the past production vehicle in operation to purify the exhaust gas, Particulate matter removal filter 65 for removing particulate matter (PM) contained in the exhaust gas discharged from the diesel engine, EGR cooling device 90, EGR cooling pump 95 and EGR valve 40 for controlling the amount of recycle exhaust gas to reduce the nitrogen oxide (NOx) contained in the exhaust gas passed through the particulate matter removal filter. Cooled EGR, Cooled EGR, Based on the monitoring results from various sensors installed in the vehicle and the engine, an EGR control map is generated so that particulate matter and nitrogen oxide contained in the exhaust gas are below the regulatory standard, and thus the EGR valve 40 and the EGR cooling are performed. A diesel engine modified exhaust gas purification system, characterized in that it comprises an EGR controller (55) for controlling the pump (95). 2. The diesel engine modified exhaust gas purification system according to claim 1, wherein the EGR controller has a self-learning function for automatically generating an EGR control map based on the type and age information of the engine input during the retrofit process. The method according to claim 1 or 2,  Along with the EGR valve opening and the operating state of the EGR cooler, it shows the calculated NOx reduction and the back pressure of the DPF, the accumulation of soot and non-combustible ash, and monitoring and warning signals if they exceed a given threshold. Diesel engine modified exhaust gas purification system, characterized in that it also comprises an EGR display unit 120 for emitting. The method according to claim 1 or 2, And bypass means for bypassing the particulate matter exhaust filter (65) when the particulate matter removal filter is clogged. In the exhaust gas purification method for the diesel engine of the past production vehicle in operation, Particulate matter removal filter 65 for removing particulate matter (PM) contained in the exhaust gas discharged from the diesel engine, EGR cooling device 90, EGR cooling pump 95 and EGR valve 40 for controlling the amount of recycle exhaust gas to reduce the nitrogen oxide (NOx) contained in the exhaust gas passed through the particulate matter removal filter. Cooled exhaust recirculation system (Cooled EGR), and A first step of additionally mounting an exhaust gas purification system including an EGR controller 55 for controlling the EGR valve 40 and the EGR cooling pump 95; The engine of the vehicle is rapidly accelerated under no load to detect the engine speed and the accelerator pedal opening range, and the particulate matter and nitrogen oxide contained in the exhaust gas are below the regulatory standard based on the EGR valve 40 and the EGR. And a second step of generating an EGR control map for controlling the cooling pump (95). The method of claim 5, The second step of generating the EGR control map Inputting the type and year information of the engine and automatically generating an initial EGR control map through self-learning, And an optimization step of continuously reflecting control characteristics that change as engine aging progresses. The method according to claim 5 or 6, The second step of generating the EGR control map In the process of optimizing the EGR control map, including the EGR control and sensitivity analysis step (S600) and the control map optimization calculation step (S500), the learning control is performed until the optimal EGR control map is converged. A method for purifying exhaust gas from diesel engine vehicles.

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