JP2004019449A - Exhaust emission control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control device for an internal combustion engine, suppressing the lowering of operativeness resulting from a change in output torque of the engine when controlling the operation of the internal combustion engine to increase an exhaust gas temperature for recovering a filter. <P>SOLUTION: The filter 18 is provided in an exhaust passage 8 for a diesel engine for trapping particulates in exhaust gas. Recovery control for removing the particulates from the filter 18 produces a change from normal engine operation emphasized on heat efficiency into engine operation intended for the increase of the exhaust gas temperature. In the engine operation intended for the increase of the exhaust gas temperature, heat efficiency is degraded more than that in the normal engine operation emphasized on the heat efficiency but a loss in output torque with the degradation of the heat efficiency is suppressed by the increase of a fuel injection amount. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an exhaust gas purification device for an internal combustion engine.
[0002]
[Prior art]
2. Description of the Related Art In recent years, there has been a demand for an internal combustion engine such as an automobile engine, particularly a diesel engine, to suppress the emission of fine particles (particulates) mainly containing soot contained in the exhaust gas into the atmosphere. In order to satisfy such requirements, for example, as disclosed in Japanese Patent Application Laid-Open No. 2001-303931, it has been considered to provide a filter for collecting particulates in exhaust gas in an exhaust passage of a diesel engine.
[0003]
The particulates collected and accumulated in the filter are subjected to an engine operation in which the exhaust gas temperature is increased, for example, a high-load high-speed operation during high-speed running, and the filter is activated up to an activation temperature as the exhaust gas temperature increases due to this operation. Burns out when heated. Therefore, when the engine operation in which the exhaust gas temperature becomes high is continued, the particulates accumulated on the filter are removed. However, particulates are removed by raising the temperature of the filter to the activation temperature because the conditions are limited, such as when high-load high-speed operation is continued. It is difficult to remove particulates from the filter.
[0004]
Therefore, the accumulation of particulates usually progresses with an increase in the engine operating time, and the particulates cause clogging of the filter, thereby lowering the trapping ability. In order to suppress such a reduction in the trapping capacity of the filter, when the particulate matter accumulation reaches a predetermined level, the exhaust temperature of the diesel engine is forcibly increased, and the filter is heated to the activation temperature by the exhaust gas, and the filter is heated. The burning of the particulates deposited on the surface is performed. By removing the particulates accumulated on the filter in this way, the trapping ability of the filter is restored (regenerated).
[0005]
As a method for forcibly raising the exhaust gas temperature for the regeneration of the filter, for example, there is a method of supplying fuel to an exhaust passage of a diesel engine and burning the fuel. However, in this method, a new fuel supply device for supplying fuel to the exhaust passage must be provided, so that the labor and cost for providing the device cannot be ignored.
[0006]
For this reason, when regenerating the filter, the operation of the diesel engine should be changed from an operation focused on thermal efficiency to an operation intended to increase the exhaust gas temperature, and the temperature of the filter should be raised to the activation temperature by this operation. Is also considered. The operation of the diesel engine intended to increase the exhaust gas temperature includes an operation in which the fuel injection timing is retarded compared to the operation in which the thermal efficiency is emphasized, and an increase in the exhaust gas recirculation amount (EGR amount) compared to the operation in which the thermal efficiency is emphasized. Driving was given.
[0007]
If the fuel injection timing is retarded as compared to the normal (thermal efficiency-oriented) operation as described above, the combustion period of the fuel shifts to the retard side. The exhaust gas is sent to the exhaust passage, and the exhaust gas temperature rises. Also, if the amount of exhaust gas recirculation is increased from that in normal (thermal efficiency-oriented) operation, the amount of cool fresh air sucked into the combustion chamber decreases, and the temperature of exhaust gas sent from the combustion chamber to the exhaust passage after fuel combustion decreases. Enhanced.
[0008]
By performing the operation intended to increase the exhaust gas temperature in this manner, the engine operating region in which the filter can be heated to the activation temperature is expanded to a low-load low-rotation side, so that the particulates accumulated on the filter are reduced. The filter can be efficiently burned and the filter can be regenerated.
[0009]
[Problems to be solved by the invention]
As described above, the operation of the diesel engine is changed from the normal operation with a focus on thermal efficiency to the operation intended to increase the exhaust gas temperature, so that the filter can be activated without providing a fuel supply device for supplying fuel to the exhaust passage. Thus, it is possible to realize an increase in the exhaust gas temperature for raising the temperature to the gasification temperature.
[0010]
However, in the operation intended to raise the exhaust gas temperature, the required output torque cannot be obtained because the thermal efficiency is lower than in the normal (thermal efficiency-oriented) operation and the output torque of the diesel engine is reduced. It is undeniable that drivability is reduced.
[0011]
Also, when the operation of the diesel engine changes from the normal operation to the operation intended to increase the exhaust gas temperature, the output torque decreases. Conversely, when the operation changes from the operation intended to increase the exhaust gas temperature to the normal operation, the output torque increases. Such a sudden change in output torque at the time of operation switching also leads to a decrease in drivability.
[0012]
The present invention has been made in view of such circumstances, and an object of the present invention is to control the operation of an internal combustion engine so as to increase the exhaust gas temperature for filter regeneration by changing the output torque of the engine. It is an object of the present invention to provide an exhaust gas purifying apparatus for an internal combustion engine that can suppress a decrease in drivability.
[0013]
[Means for Solving the Problems]
Hereinafter, the means for achieving the above object and the effects thereof will be described.
In order to achieve the above object, according to the first aspect of the present invention, in an exhaust gas purifying apparatus for an internal combustion engine including a filter for trapping fine particles contained in exhaust gas of the internal combustion engine, the operation of the internal combustion engine is controlled so that the exhaust gas temperature increases. Means for executing regeneration control for burning out the fine particles trapped by the filter, and increasing the fuel injection amount of the internal combustion engine during the regeneration control by an amount capable of suppressing a decrease in engine torque due to the regeneration control. Means.
[0014]
In the engine operation for raising the exhaust gas temperature during the regeneration control, the thermal efficiency is lower than that in the normal engine operation in which the thermal efficiency is emphasized, but the decrease in the output torque due to the decrease in the thermal efficiency is suppressed by increasing the fuel injection amount. A decrease in drivability due to the decrease in the output torque can be suppressed.
[0015]
According to a second aspect of the present invention, in the first aspect of the present invention, the regeneration unit executes the regeneration control by changing an operation of the internal combustion engine from an operation that emphasizes thermal efficiency to an operation that intends to increase the exhaust gas temperature. And an engine operation change from the operation in which the thermal efficiency is emphasized at the start of the regeneration control to the operation intended to increase the exhaust temperature, and the operation intended to increase the exhaust temperature at the end of the regeneration control. An operation gradual change means for gradually changing at least one of the engine operation change to the operation with an emphasis on thermal efficiency is further provided.
[0016]
When the operation of the internal combustion engine is changed between the operation that emphasizes thermal efficiency and the operation that intends to raise the exhaust gas temperature at the start and end of the regeneration control, the change is performed gradually, and the output torque changes due to the change. Even if it does, it can be suppressed from becoming sudden.
[0017]
According to a third aspect of the present invention, in the first or second aspect of the invention, the fuel injection amount is gradually changed in at least one of the time when the fuel injection amount is increased by the amount increasing means and the time when the increase is completed. A fuel gradual change means is further provided.
[0018]
When the increase in the fuel injection amount by the increase means is started or when the increase is finished, it is possible to suppress a sudden change in the fuel injection amount and a large output torque change. Further, when the engine operation changes gradually with the start or end of the regeneration control, the fuel injection amount can be gradually changed in accordance with the change speed. Accordingly, the output torque tends to change gradually, but the fuel injection amount is increased correspondingly, and the output torque change can be appropriately suppressed.
[0019]
According to a fourth aspect of the present invention, in the exhaust gas purifying apparatus for an internal combustion engine provided with a filter for trapping particulates contained in the exhaust gas of the internal combustion engine, the operation of the internal combustion engine is changed from an operation focusing on thermal efficiency to an operation intended to increase the exhaust gas temperature. Changing the exhaust temperature of the engine to perform regeneration control for burning out the fine particles trapped in the filter; and performing the exhaust control from the operation that emphasizes the thermal efficiency at the start of the regeneration control. At least one of the engine operation change to the operation intended to increase the temperature and the engine operation change from the operation intended to increase the exhaust gas temperature to the operation that emphasizes the thermal efficiency at the end of the regeneration control is gradually changed. Operation changing means.
[0020]
In the engine operation intended to increase the exhaust gas temperature performed during the regeneration control, the thermal efficiency is lower and the output torque is lower than in the normal engine operation in which the thermal efficiency is emphasized. Therefore, when the operation of the internal combustion engine is changed between the operation with an emphasis on thermal efficiency and the operation intended to increase the exhaust gas temperature at the start and end of the regeneration control, a sudden change in the output torque may occur and the drivability may be reduced. is there. However, a decrease in drivability due to such a sudden change in output torque is suppressed by gradually changing the engine operation.
[0021]
According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the regenerating means normally operates a throttle valve provided in an intake / exhaust system of the internal combustion engine as an engine operation for increasing exhaust gas temperature. The operation is performed in a state in which the engine is controlled to be more closed than the engine operation that emphasizes thermal efficiency.
[0022]
The throttle valve provided in the intake / exhaust system of the internal combustion engine is closed, for example, to stop the engine promptly during an engine stop process, or is controlled to a closed side to reduce thermal efficiency during warm-up operation to promote warm-up. Or something. By controlling the throttle valve having such a role to the closed side during the execution of the regeneration control, the rotational resistance of the internal combustion engine increases, the thermal efficiency decreases, and much of the combustion energy of the engine is transmitted to the exhaust as heat, and the exhaust temperature is reduced. The temperature of the filter rises to a value at which the temperature can be raised to the activation temperature. Therefore, without providing a special device for raising the exhaust gas temperature, it is possible to raise the exhaust gas temperature by using the throttle valve provided in the internal combustion engine and appropriately raise the temperature of the filter for burning off the accumulated particulates. Become like
[0023]
According to a sixth aspect of the present invention, in the invention according to any one of the first to fifth aspects, as the engine operation for increasing the exhaust gas temperature, the regeneration means uses a supercharging pressure by a supercharging system provided in the internal combustion engine. It is assumed that the operation in the lowered state is executed.
[0024]
When air is being supercharged into the internal combustion engine by the supercharging system, the amount of cool fresh air sucked into the combustion chamber increases, so that the rise in exhaust gas temperature is suppressed. According to the above configuration, when the regeneration control is executed, the supercharging pressure is reduced and the amount of the cool fresh air sucked into the combustion chamber is reduced, so that the exhaust gas temperature increases the filter to the activation temperature. Will rise to a value that is possible. Therefore, without providing a special device for raising the exhaust gas temperature, the temperature of the filter for raising the exhaust gas temperature by using the supercharging system provided in the internal combustion engine and appropriately burning out the accumulated particulates is appropriately adjusted. Will be able to do it.
[0025]
In the invention according to claim 7, in the invention according to any one of claims 1 to 6, the regenerating means sets the fuel injection timing of the internal combustion engine as the engine operation for increasing the exhaust gas temperature as compared with the engine operation in which thermal efficiency is emphasized. The engine operation is performed in a state where the engine is controlled to the retard side.
[0026]
When the fuel injection timing is retarded, the combustion period of the fuel is shifted to the retard side, and the gas after fuel combustion is sent out as high temperature exhaust gas from the combustion chamber to the exhaust passage, thereby increasing the exhaust gas temperature. . According to the above configuration, when the regeneration control is performed, the fuel injection timing is retarded, so that the exhaust gas temperature rises to a value at which the temperature of the filter can be raised to the activation temperature. Therefore, without providing a special device for raising the exhaust gas temperature, it is possible to raise the exhaust gas temperature by using the throttle valve provided in the internal combustion engine and appropriately raise the temperature of the filter for burning off the accumulated particulates. Become like
[0027]
According to an eighth aspect of the present invention, in the invention according to any one of the first to seventh aspects, the regeneration means performs an exhaust gas recirculation by an exhaust gas recirculation mechanism provided in the internal combustion engine as an engine operation for increasing the exhaust gas temperature. The engine operation is performed in a state where the amount is controlled to be increased from the engine operation that emphasizes thermal efficiency.
[0028]
When the amount of exhaust gas recirculation is increased, the amount of cooled fresh air sucked into the combustion chamber is reduced, so that the temperature of exhaust gas sent from the combustion chamber to the exhaust passage after fuel combustion is increased. According to the above configuration, when the regeneration control is performed, the exhaust gas recirculation amount is increased, so that the exhaust gas temperature rises to a value that can raise the temperature of the filter to the activation temperature. Therefore, without providing a special device for raising the exhaust gas temperature, it is possible to raise the exhaust gas temperature by using the throttle valve provided in the internal combustion engine and appropriately raise the temperature of the filter for burning off the accumulated particulates. Become like
[0029]
According to a ninth aspect of the present invention, in the invention according to any one of the first to eighth aspects, when the idling operation is being performed, the regenerating means sets the idling rotational speed to be higher than the normal operation as the engine operation for increasing the exhaust gas temperature. The idle operation is also performed in a state where the pressure is raised.
[0030]
Increasing the idling rotational speed increases the rotational resistance of the internal combustion engine, lowers thermal efficiency, and increases the amount of combustion energy of the engine transmitted to the exhaust as heat, so that the exhaust temperature is increased. become. According to the above configuration, the idle rotation speed is increased during execution of the engine operation for increasing the exhaust gas temperature, and thereby the exhaust gas temperature is increased. Therefore, it is possible to appropriately increase the temperature of the filter for burning off the accumulated particulates. Become like
[0031]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment in which the present invention is embodied in an exhaust gas purification device for an automobile diesel engine will be described with reference to FIGS.
[0032]
In the diesel engine 1 shown in FIG. 1, air is sucked into the combustion chamber 3 through the intake passage 2, and fuel injected from the fuel injection valve 4 is burned in the combustion chamber 3. It is driven by reciprocating the piston 5 with energy. The reciprocating movement of the piston 5 is converted by the connecting rod 6 into rotation of a crankshaft 7 which is an output shaft of the diesel engine 1. The gas after burning the fuel in the combustion chamber 3 is sent to the exhaust passage 8 as exhaust gas.
[0033]
Part of the exhaust gas sent to the exhaust passage 8 is returned to the intake passage 2 by an exhaust gas recirculation mechanism (EGR mechanism) 9. The EGR mechanism 9 includes an EGR passage 10 for flowing exhaust gas from the exhaust passage 8 to the intake passage 2 and an opening / closing operation for adjusting an amount of exhaust gas (EGR amount) provided in the EGR passage 10 and passing through the passage 10. An EGR valve 11 is provided. The exhaust gas recirculation by the EGR mechanism 9 is performed to reduce the combustion temperature of the fuel to suppress the generation of nitrogen oxides (NOx) and reduce the NOx emission of the diesel engine 1.
[0034]
A portion of the exhaust passage 8 downstream of the EGR passage 10 and a portion of the intake passage 2 upstream of the EGR passage 10 are connected to a turbocharger 12 constituting a supercharging system. The turbocharger 12 includes a compressor wheel 13 for sending air to a downstream side of the intake passage 2 and a turbine wheel 14 that rotates based on a flow of exhaust gas passing through the exhaust passage 8. When the turbine wheel 14 rotates, the compressor wheel 13 rotates integrally therewith, thereby increasing the intake pressure (supercharging pressure) of the diesel engine 1 and improving the engine output.
[0035]
A bypass passage 15 is connected to the exhaust passage 8 so as to bypass the turbocharger 12, and the passage 15 is provided with a wastegate valve 16 that opens and closes to make the exhaust circulation area variable. Therefore, by controlling the opening degree of the wastegate valve 16 and making the amount of exhaust gas passing through the bypass passage 15 variable, the amount of exhaust gas flowing to the turbine wheel 14 side is changed, and the rotation speed of the turbocharger 12 is adjusted. can do. By adjusting the rotation speed of the turbocharger 12, the supercharging pressure of the diesel engine 1 is changed.
[0036]
Downstream of the turbocharger 12 in the exhaust passage 8, there is provided an exhaust throttle valve 17 that is opened and closed at the time of starting the engine stop or after the cold start of the engine. When the exhaust throttle valve 17 is controlled to the closed side, the exhaust resistance of the diesel engine 1 increases. Therefore, at the start of engine stop, the exhaust throttle valve 17 is closed, and the engine speed is rapidly reduced by the exhaust resistance. Further, even after the cold start of the engine, the exhaust throttle valve 17 is closed, the rotational resistance of the diesel engine 1 is increased by the exhaust resistance, and the thermal efficiency is reduced. As a result, much of the combustion energy is transmitted to the engine 1 as heat, and warm-up is promoted.
[0037]
Downstream of the exhaust throttle valve 17 in the exhaust passage 8, there is provided a filter 18 for collecting fine particles (particulates) containing soot as a main component contained in the exhaust gas. The particulates collected and deposited by the filter 18 will be burned out when the filter 18 is heated to the activation temperature. The engine operating state in which the temperature of the filter 18 rises to the activation temperature in this way includes, for example, a state in which high-speed high-load operation due to high-speed running is continued and a state in which the exhaust gas temperature is high is continued. Therefore, in the operation state other than the above, the particulates collected in the filter 18 accumulate, and in the above-described operation state, the particulates are removed from the filter 18.
[0038]
Next, the electrical configuration of the exhaust gas purification device according to the present embodiment will be described.
This exhaust gas purification device includes an electronic control device 20 mounted on an automobile to control the operation of the diesel engine 1. The electronic control unit 20 receives detection signals from the following various sensors.
[0039]
A supercharging pressure sensor 21 for detecting a pressure (supercharging pressure) in the intake passage 2;
A crank position sensor 22 that outputs a signal corresponding to the rotation of the crankshaft 7;
[0040]
A back pressure sensor 23 for detecting a pressure (back pressure) on the upstream side of the exhaust throttle valve 17 in the exhaust passage 8;
An accelerator position sensor 25 for detecting the amount of depression of an accelerator pedal 24 (accelerator depression amount) operated by the driver of the automobile.
[0041]
The electronic control unit 20 determines a fuel injection amount, a fuel injection timing, and an EGR amount based on an accelerator depression amount obtained from a detection signal of the accelerator position sensor 25, an engine rotation speed obtained from a detection signal of the crank position sensor 22, and the like. Is calculated. Then, by driving the fuel injection valve 4 and the EGR valve 11 based on these command values, the fuel injection amount, the fuel injection timing, and the EGR are set so that the engine operation with good thermal efficiency and exhaust emission can be obtained. Control the amount.
[0042]
Further, the electronic control unit 20 also performs idle speed control and drive control of the wastegate valve 16 and the exhaust throttle valve 17. That is, the fuel injection amount is adjusted by driving the fuel injection valve 4 so that the engine rotation speed (idling rotation speed) approaches the predetermined target idle rotation speed during the idling operation. When the supercharging pressure obtained based on the detection signal from the supercharging pressure sensor 21 excessively increases, the supercharging pressure is reduced by opening the waste gate valve 16 which is normally closed. Further, after the cold start of the engine and after the start of the engine stop, the exhaust throttle valve 17 which is normally in the open state is controlled to the closed side as described above, thereby promoting warm-up and promptly stopping the engine.
[0043]
By the way, during the operation of the engine, the particulates in the exhaust gas are collected by the filter 18. Further, in an engine operating state in which the exhaust temperature has a value at which the temperature of the filter 18 can be raised to the activation temperature or higher, the particulates accumulated on the filter 18 are burned and removed. The total amount of particulates generated during engine operation is related to fuel consumption, and the amount of particulates removed from filter 18 is related to exhaust temperature. Therefore, the particulate accumulation amount DEP in the filter 18 is used for calculating the command value of the fuel injection amount and also used for determining whether or not the engine is in the engine operating state in which the exhaust gas temperature has the above value. It can be estimated based on the accelerator pedal depression amount and the engine rotation speed, which are the possible parameters.
[0044]
That is, as the accumulation amount DEP, a change amount ΔDEP of particulates accumulated on the filter 18 is calculated based on the accelerator pedal depression amount and the engine rotation speed at every predetermined period, and the change amount ΔDEP is added at each predetermined period. You will be able to get it. As a method of calculating the change amount ΔDEP, a method of calculating the change amount ΔDEP by referring to a map which is set in advance by an experiment or the like is considered. The change amount ΔDEP takes a negative value when the engine operation state known from the accelerator pedal depression amount and the engine rotation speed is in an engine operation region where the temperature of the filter 18 can be raised to the activation temperature. Takes a positive value when the engine is in the engine operation range.
[0045]
The condition in which the temperature of the filter 18 rises to the activation temperature is usually limited, for example, when the high-load high-rotation state during high-speed running is continued. This is less than the opportunity to take a positive value, and the deposition amount DEP gradually increases. When the accumulation amount DEP becomes equal to or more than the allowable value, the regeneration control for forcibly raising the temperature of the filter 18 to remove the accumulated particulates and recovering (regenerating) the collecting ability of the filter 18 is performed through the electronic control device 20. Be executed. In this regeneration control, the operation of the diesel engine 1 is changed from a normal operation with an emphasis on thermal efficiency to an operation intended to increase the exhaust gas temperature. By performing such an operation, the temperature of the filter 18 is raised to the activation temperature.
[0046]
Here, the change in the operation state of the diesel engine 1 in the regeneration control, that is, the change between the operation in which the normal thermal efficiency is emphasized and the operation intended to increase the exhaust gas temperature will be described with reference to time charts in FIGS. I do. 2A to 2E show changes in the fuel injection timing, the EGR amount, the back pressure, and the fuel injection amount, respectively, and FIG. 3 shows changes in the idle speed during the idling operation. ing.
[0047]
When the regeneration control is started when the accumulation amount DEP becomes equal to or more than the allowable value, the retardation of the fuel injection timing, the increase of the EGR amount, the reduction of the supercharging pressure, and the reduction of the back pressure with respect to the normal engine operation that emphasizes thermal efficiency. The pressure increase is performed, and the engine operation in such a state is executed as an operation for increasing the exhaust gas temperature. Further, when the regeneration control is executed during the idling operation, the idling rotational speed is increased as compared with the normal operation, and the engine operation in this state is also executed as an operation for increasing the exhaust gas temperature. As described above, the operation of the diesel engine 1 is changed from a normal operation with an emphasis on thermal efficiency to an operation intended to increase the exhaust gas temperature.
[0048]
As shown in FIG. 2A, the fuel injection timing is retarded by the retard amount B. That is, the command value for the fuel injection timing is set to a value on the retard side by the retard amount B, and by driving the fuel injection valve 4 based on this command value, the retard of the fuel injection timing as described above is reduced. Done. By operating the diesel engine 1 with the fuel injection timing retarded in this way, the combustion engine of the fuel shifts to the retard side, and the gas after combustion of the fuel is discharged from the combustion chamber 3 as a high temperature exhaust gas. The exhaust gas is sent to the passage 8 and the exhaust gas temperature is increased.
[0049]
As shown in FIG. 2B, the EGR amount is increased by the increase amount C. That is, the command value for the EGR amount is set to a value on the increase side by the increase amount C, and by driving the EGR valve 11 based on this command value, the EGR amount is increased as described above. By operating the diesel engine 1 with the EGR amount increased in this manner, the amount of cool fresh air sucked into the combustion chamber 3 from the intake passage 2 by the increase in the EGR amount decreases, and fuel combustion occurs. The temperature of the exhaust gas sent out from the combustion chamber 3 to the exhaust passage 8 later is increased.
[0050]
As shown in FIG. 2C, the supercharging pressure is reduced by the reduced pressure amount D. That is, the waste gate valve 16 is driven from the fully closed state to the open side by an opening corresponding to the above-mentioned depressurized amount D, and the rotational speed of the turbocharger 12 is reduced. The pressure is reduced by D minutes. By operating the diesel engine 1 with the supercharging pressure reduced in this way, the amount of cool fresh air sucked into the combustion chamber 3 from the intake passage 2 is reduced, and the fuel is discharged from the combustion chamber 3 to the exhaust passage 3 after combustion. The temperature of the exhaust gas sent out to 8 is increased.
[0051]
As shown in FIG. 2D, the back pressure is increased by the pressure increase amount E. That is, the exhaust throttle valve 17 is driven from the fully open state to the close side by an opening degree corresponding to the pressure increase amount E, whereby the exhaust resistance of the diesel engine 1 increases, and the back pressure increases as described above. The pressure will be increased by the minute. By operating the diesel engine 1 with the back pressure increased in this manner, the rotational resistance of the engine 1 increases, the thermal efficiency decreases, and much of the combustion energy during fuel combustion is transmitted to the exhaust as heat. Therefore, the exhaust gas temperature is increased.
[0052]
As shown in FIG. 3, the idling speed is increased by the increase amount A during the idling operation. That is, the target idle rotation speed is increased by the increase amount A, whereby the idle rotation speed increases by the increase amount A. As described above, when the idling rotational speed increases, the rotational resistance of the diesel engine 1 increases, the thermal efficiency decreases, and much of the combustion energy during fuel combustion is transmitted to the exhaust as heat. Will be able to
[0053]
The retardation amount B, the increase amount C, the pressure decrease amount D, and the pressure increase amount E may be fixed values, or may be variable depending on the engine operation state such as the accelerator pedal depression amount and the engine rotation speed. It may be a value. When calculating the retardation amount B, the increase amount C, the pressure reduction amount D, and the pressure increase amount E as such variable values, it is considered that the calculation is performed with reference to a map or by a calculation formula. Can be Further, a fixed value is adopted as the increase amount A of the idle rotation speed.
[0054]
When the engine is being operated to increase the exhaust gas temperature as described above, the engine operation region in which the temperature of the filter 18 can be increased to the activation temperature is expanded to the low load and low rotation side. For example, when the engine operation is performed with an emphasis on thermal efficiency, the filter 18 is set to a limit engine operation state at which the temperature of the filter 18 can be raised to the activation temperature, and a combination of the engine load and the engine rotation speed indicated by a solid line L1 in FIG. Suppose that the engine is operated by In this state, when the engine operation is changed to the operation for increasing the exhaust gas temperature, the combination of the engine load and the engine rotation speed shifts to the low-load low-rotation side as shown by a solid line L2 in FIG.
[0055]
As described above, the engine operating region in which the temperature of the filter 18 can be raised to the activation temperature is expanded to the low-load and low-rotation side, so that the filter 18 easily reaches the activation temperature, and the chance of burning the accumulated particulates increases. As a result, the amount of particulates removed from the filter 18 becomes larger than the amount of particulates collected by the filter 18. By continuing this state for a predetermined time or longer, the particulates accumulated on the filter 18 are removed, and the collecting ability of the filter 18 is restored (regenerated).
[0056]
Further, when the time required for the filter regeneration has elapsed after the start of the regeneration control, an instruction to terminate the regeneration control is issued, and the above-described retardation of the fuel injection timing, increase of the EGR amount, reduction of the supercharging pressure, and reduction of the back pressure are performed. The pressure increase is not performed, and the normal engine operation that emphasizes thermal efficiency is executed. In this way, the operation of the diesel engine 1 is changed from an operation intended to increase the exhaust gas temperature to an ordinary operation that emphasizes thermal efficiency.
[0057]
By the way, when the engine is operated to raise the exhaust gas temperature, the thermal efficiency is reduced as compared with the normal engine operation in which the thermal efficiency is emphasized, so even if the accelerator depression amount indicating the output request from the driver is constant, the diesel The output torque of the engine 1 will decrease.
[0058]
Therefore, when the accelerator pedal depression amount changes under the condition of the constant engine rotation speed, the output torque of the diesel engine 1 changes as shown by a solid line in FIG. In the engine operation intended to increase the temperature, the transition is performed as indicated by the dashed line. For this reason, when the engine operation is changed from a normal operation with an emphasis on thermal efficiency to an operation intended to increase the exhaust gas temperature, the output torque required by the driver cannot be obtained, and the drivability (drivability) is reduced. Occurs.
[0059]
In addition, when the regeneration control starts to change from a normal operation with an emphasis on thermal efficiency to an operation intended to increase the exhaust temperature, the output torque of the diesel engine 1 decreases. The output torque of the diesel engine 1 increases when the operation changes to a normal operation that emphasizes thermal efficiency. For this reason, the output torque of the diesel engine 1 changes at the time of the start and the end command of the regeneration control, and the drivability is reduced even when the output torque is abrupt.
[0060]
Therefore, in this embodiment, the following measures (A) and (B) are taken in order to suppress the decrease in drivability as described above.
(A) During the regeneration control, the fuel injection amount of the diesel engine 1 is increased by the increase amount F as shown in FIG. 2 (e), and a decrease in torque accompanying engine operation intended to increase exhaust gas temperature is suppressed.
[0061]
(B) A change in the engine operation performed at the start of the regeneration control and at the end of the regeneration control, that is, a change between an engine operation that emphasizes normal thermal efficiency and an engine operation intended to increase the exhaust gas temperature is gradually performed.
[0062]
The increase amount F of the fuel injection amount in the measure (A) is calculated based on the accelerator pedal depression amount and the engine rotation speed, for example, as described below.
Assuming that the engine speed is constant and the accelerator pedal depression amount is a value indicated by M1 in FIG. 5 during normal engine operation with an emphasis on thermal efficiency, if the engine operation intended to increase the exhaust gas temperature is executed in this state, the output torque is increased. In order not to cause a change, it is necessary to increase the fuel injection amount to a value at which the accelerator depression amount becomes M2. Therefore, the accelerator depression amount F is set so that the difference ΔQ between the fuel injection amount Q2 when the accelerator depression amount is M2 and the fuel injection amount Q1 when the accelerator depression amount is M1 (FIG. 5B) is the increase amount F. It is calculated based on the quantity and the engine speed.
[0063]
Regarding the measure (B), the gradual change in the operation between the normal thermal efficiency-oriented engine operation and the engine operation intended to increase the exhaust gas temperature is caused by the fuel injection timing, the EGR amount, and the supercharging pressure accompanying the change in the operation. , Back pressure, and idle speed are gradually changed as shown in FIGS. 2 and 3. That is, in the change from the operation in which the thermal efficiency is emphasized to the operation in which the exhaust gas temperature is intended to be increased, the fuel injection timing is retarded by the retard amount B, the EGR amount is increased by the amount C, and the supercharging pressure is reduced by the amount D. , The pressure increase by the back pressure increase amount E, and the increase by the increase amount A of the idle rotation speed are gradually performed. Further, in the change from the operation intended to increase the exhaust gas temperature to the operation that emphasizes the thermal efficiency, the advance of the fuel injection timing by the retard amount B, the decrease by the increase amount C of the EGR amount, and the decrease amount D by the supercharging pressure , The pressure decrease by the back pressure increase amount E, and the decrease by the increase amount A of the idle rotation speed are gradually performed.
[0064]
Therefore, by executing the above measure (A), it is possible to suppress a decrease in engine operability due to a decrease in output torque during the regeneration control. Output torque reduction during regeneration control can be suppressed. Further, by executing the above-described measure (B), even if the output torque changes at the start of the regeneration control or at the end of the regeneration control, it is possible to suppress the change from being abrupt and leading to a decrease in drivability. be able to.
[0065]
Next, the execution procedure of the reproduction control will be described with reference to a flowchart of FIG. 6 showing a reproduction control routine. This reproduction control routine is executed by the electronic control unit 20 at, for example, a time interruption every predetermined time.
[0066]
In the regeneration control routine, first, it is determined whether or not the regeneration control is started, which is started when the amount of particulate DEP accumulated in the filter 18 becomes equal to or more than the allowable value (S101).
[0067]
If an affirmative determination is made here, the above-described setting of the increase amount A of the idling rotational speed is performed on condition that the idling operation is being performed (S102: YES) (S103). The determination that the vehicle is idling is performed based on, for example, that the accelerator pedal depression amount is “0” and the engine speed is less than a predetermined value.
[0068]
Subsequently, calculation of the retard amount B of the injection timing (S104), calculation of the increase amount C of the EGR amount (S105), calculation of the reduction amount D of the supercharging pressure (S106), and calculation of the back pressure increase amount E The calculation (S107) is sequentially performed based on the accelerator depression amount and the engine speed as described above. The retardation amount B, the increase amount C, the pressure decrease amount D, and the pressure increase amount E are used when performing an engine operation for increasing the exhaust gas temperature during the regeneration control. Thereafter, the increase amount F of the fuel injection amount is also calculated based on the accelerator pedal depression amount and the engine speed as described above (S108). This increase amount F is used when increasing the fuel injection amount so that the output torque does not decrease when the engine is operated to increase the exhaust gas temperature during the regeneration control.
[0069]
On the other hand, if a negative determination is made in step S101, it is determined whether or not the reproduction control is being performed (S109). If an affirmative determination is made here, for each of the parameters such as the idle speed, the fuel injection timing, the EGR amount, the boost pressure, the back pressure, and the fuel injection amount, the increase amount A, the retard amount B, the increase amount C, A process for reflecting the reduced pressure amount D, the increased pressure amount E, and the increased amount F is executed (S110). The detailed procedure of this processing will be described with reference to the flowcharts of FIGS. The reflection routine is executed through the electronic control unit 20 every time the process proceeds to step S110 (FIG. 6) of the reproduction control routine.
[0070]
In the reflection routine, when the elapsed time from the start of the reproduction control is less than the predetermined time t1 (S201 in FIG. 7: YES), the increase amount A, the retard amount B, the increase amount C, the pressure decrease The amount D, the pressure increase amount E, and the increase amount F are gradually reflected (S202 to S208). Further, when the elapsed time from the start of the reproduction control is equal to or longer than the predetermined time t1 (S201: NO), on the condition that there is no instruction to end the reproduction control (S209: YES in FIG. 8), The increase / decrease is continued (S210 to S216). Note that the predetermined time t1 is set to a time longer than a time required to fully reflect the increase or decrease of each parameter.
[0071]
On the other hand, when the end command of the control is given during the reproduction control (S209: NO), and when the elapsed time from the command is less than the predetermined time t2 (S217: YES in FIG. 9), the above-described parameters are set. Is gradually returned to “0” (S218 to S224). When the elapsed time since the end command of the reproduction control is equal to or longer than the predetermined time t2 (S217: NO), the increase or decrease of each of the above parameters is set to "0". (S225 to S231 in FIG. 10). Note that the predetermined time t2 is set to a time longer than a time required to return the increase / decrease of each parameter to “0”.
[0072]
Next, the above-described [1] the processes of steps S202 to S208, [2] the processes of steps S210 to S216, [3] the processes of steps S218 to S224, and [4] the processes of steps S225 to S231 are individually described in detail. explain.
[0073]
[1] For each parameter such as idle rotation speed, fuel injection timing, EGR amount, supercharging pressure, back pressure, and fuel injection amount, increase amount A, retard amount B, increase amount C, pressure decrease amount D, pressure increase Processing to gradually reflect the amount E and the increase amount F (S202 to S208 in FIG. 7).
[0074]
In this process, first, on condition that the engine is idling (S202: YES), the target idle speed is gradually increased at a predetermined increase rate, whereby the idle speed becomes as shown in FIG. It is gradually raised (S203). Such an increase in the idling rotational speed is continued until it increases by the increase amount A.
[0075]
As for the fuel injection timing, the command value is gradually retarded at a predetermined delay ratio, and the fuel injection valve 4 is driven based on the command value, as shown in FIG. It is gradually retarded (S204). Such retarding of the fuel injection timing is continued until it is retarded by the retarding amount B.
[0076]
As for the EGR amount, the command value is gradually increased at a predetermined increase rate, and the EGR valve 11 is driven based on the command value, so that the EGR amount is gradually increased as shown in FIG. (S205). The increase in the EGR amount is continued until the amount is increased by the increase amount C.
[0077]
As for the supercharging pressure, the wastegate valve 16 is gradually opened from the fully closed state by the opening corresponding to the decompression amount D, so that the pressure is gradually reduced as shown in FIG. Is performed (S206). The pressure reduction of the supercharging pressure is continued until the pressure is reduced by the reduced pressure amount D.
[0078]
The back pressure is gradually increased as shown in FIG. 2D by gradually driving the exhaust throttle valve 17 from the fully open state to the closing side by an opening corresponding to the pressure increase amount E. (S207). The pressure increase of the back pressure is continued until the pressure is increased by the pressure increase amount E.
[0079]
As for the fuel injection amount, the command value is gradually increased at a predetermined increase rate, and by driving the fuel injection valve 4 based on the command value, the fuel injection amount is gradually increased as shown in FIG. (S208). Such an increase in the fuel injection amount is continued until the fuel injection amount is increased by the increase amount F.
[0080]
[2] Processing for continuing the increase / decrease state of each parameter (S210 to S216 in FIG. 8).
In this process, first, on condition that the engine is idling (S210: YES), the target idle rotation speed is maintained in a state of being increased by the increase amount A, whereby the idle rotation speed becomes as shown in FIG. It is maintained in a state where it has increased by the increase amount A (S211). Such an increase of the idle rotation speed by the increase amount A is continued until the end command of the regeneration control is issued.
[0081]
With respect to the fuel injection timing, the command value is maintained in a state of being retarded by the amount of retardation B, whereby the fuel injection timing is retarded by the amount of retardation B as shown in FIG. Is maintained (S212). Such retardation of the fuel injection timing by the retardation amount B is continued until a regeneration control end command is issued.
[0082]
The EGR amount is maintained in a state where the command value is increased by the increase amount C, and thereby the EGR amount is maintained in a state where the EGR amount is increased by the increase amount C (S213). ). Such an increase of the EGR amount by the increase amount B is continued until the regeneration control end command is issued.
[0083]
As for the supercharging pressure, the waste gate valve 16 is maintained in a state where it is opened from the fully closed position by an opening corresponding to the depressurizing amount D, whereby the supercharging pressure is reduced as shown in FIG. The state where the pressure is reduced by D is maintained (S214). The pressure reduction by the pressure reduction amount D of the supercharging pressure is continued until the regeneration control end command is issued.
[0084]
As for the back pressure, the exhaust throttle valve 17 is maintained in a state in which the exhaust throttle valve 17 is closed by the opening corresponding to the boosting amount E from the full opening, whereby the back pressure is increased as shown in FIG. The pressure is maintained in a state where the pressure is increased by an amount (S215). Such pressure increase by the back pressure increase amount E is continued until a regeneration control end command is issued.
[0085]
As for the fuel injection amount, the command value is maintained in a state where it is increased by the amount of increase F, whereby the fuel injection amount is maintained in a state where it is increased by the amount of increase F as shown in FIG. (S216). Such an increase in the fuel injection amount is continued until a regeneration control end command is issued.
[0086]
[3] Processing to gradually return the increase / decrease of each parameter to “0” (steps (S218 to S224 in FIG. 9)).
In this process, first, on condition that the engine is idling (S218: YES), the target idle speed is gradually reduced at a predetermined reduction rate, whereby the idle speed becomes as shown in FIG. It is gradually lowered (S219). Such a decrease in the idling rotational speed is continued until the idling rotational speed decreases by the increase amount A.
[0087]
As for the fuel injection timing, the command value is gradually advanced at a predetermined advance ratio, and the fuel injection valve 4 is driven based on the command value, as shown in FIG. The angle is gradually advanced (S220). Such advancement of the fuel injection timing is continued until it is advanced by the retardation amount B.
[0088]
As for the EGR amount, the command value is gradually reduced at a predetermined reduction rate, and the EGR valve 11 is driven based on the command value, so that the EGR amount is gradually reduced as shown in FIG. (S221). Such a decrease in the EGR amount is continued until the amount is decreased by the increase amount C.
[0089]
The supercharging pressure is gradually increased as shown in FIG. 2 (c) by gradually driving the wastegate valve 16 to the closed side toward the fully closed state (S222).
[0090]
The back pressure is gradually reduced as shown in FIG. 2D by gradually driving the exhaust throttle valve 17 toward the fully open state to the open side (S223).
[0091]
As for the fuel injection amount, the command value is gradually reduced at a predetermined reduction rate, and by driving the fuel injection valve 4 based on the command value, the fuel injection amount is gradually reduced as shown in FIG. (S224). Such reduction of the fuel injection amount is continued until the fuel injection amount is reduced by the increase amount F.
[0092]
[4] Processing for setting the increase / decrease of each of the above parameters to “0” (steps S225 to S231 in FIG. 10).
In this process, first, on condition that the engine is idling (S225: YES), the target idle speed is reduced by the increase amount A, thereby increasing the idle speed as shown in FIG. The state is returned to a state where the amount A is not reflected (S226).
[0093]
As for the fuel injection timing, the command value is advanced by the amount of retard B, whereby the fuel injection timing does not reflect the amount of retard B as shown in FIG. (S227).
[0094]
The EGR amount is set to a state in which the EGR amount is decreased by the increase amount C of the command value, thereby returning the EGR amount to a state in which the increase amount C is not reflected as shown in FIG. 2B (S228). )
As for the supercharging pressure, the wastegate valve 16 is fully closed, whereby the supercharging pressure is returned to a state in which the pressure reduction amount D is not reflected as shown in FIG. 2C (S229).
[0095]
As for the back pressure, the exhaust throttle valve 17 is fully opened, thereby returning the back pressure to a state in which the increased pressure amount E is not reflected as shown in FIG. 2D (S230).
[0096]
As for the fuel injection amount, the command value is reduced by the increase amount F, whereby the fuel injection amount does not reflect the increase amount F as shown in FIG. 2 (e). (S231).
[0097]
According to the embodiment described above, the following effects can be obtained.
(1) In the engine operation in which the exhaust gas temperature is increased during the regeneration control, the thermal efficiency is lower than that in the normal engine operation in which the thermal efficiency is emphasized. Can be suppressed by increasing the amount of. Assuming that such an increase in the fuel injection amount is not performed, when the accelerator pedal 24 is depressed by a predetermined amount during the regeneration control, the output torque of the diesel engine 1 becomes lower than that in the normal operation in which the thermal efficiency is emphasized. Drivability decreases. However, by increasing the fuel injection amount during the regeneration control, it is possible to suppress a decrease in drivability due to such a decrease in output torque.
[0098]
(2) The increase amount F is calculated based on the accelerator pedal depression amount and the engine rotation speed, and the torque decrease when the engine operation is switched from the normal operation with an emphasis on thermal efficiency to the engine operation intended to increase the exhaust gas temperature in the engine operation state. The value is set to a value corresponding to the amount of fuel required to compensate for the minute (for example, the difference ΔQ in FIG. 5B). Therefore, during the regeneration control, the decrease in the output torque can be accurately suppressed by increasing the fuel injection amount by the increase amount F.
[0099]
(3) The exhaust temperature of the diesel engine 1 rises in response to an increase in the fuel injection amount. That is, under the condition that the engine rotation speed is constant, the fuel injection amount changes as shown in, for example, FIG. 5B with respect to the change in the accelerator depression amount, and the exhaust gas temperature also changes in accordance with the change in the fuel injection amount. It changes as shown in FIG. Therefore, when the fuel injection amount is increased by the increase amount F, that is, the difference ΔQ in FIG. 5B during the regeneration control as described above, the exhaust gas temperature increases from the temperature T1 to the temperature T2 by the temperature difference corresponding to the difference ΔQ. Since the temperature rises by ΔT, the temperature of the filter 18 easily rises to the activation temperature.
[0100]
(4) When the engine operation changes from the operation that emphasizes normal thermal efficiency to the operation intended to increase the exhaust gas temperature at the start of the regeneration control, and from the operation intended to increase the exhaust gas temperature to the operation that emphasizes the normal thermal efficiency when the regeneration control end command is issued. As they change, these changes in operation occur gradually. Further, at the start of the regeneration control (at the start of the fuel injection amount increase) and at the time of the regeneration control end command (at the end of the fuel injection amount increase), the change in the fuel injection amount changes in accordance with the gradual change of the engine operation. It is gradually changed as shown in FIG. Therefore, when the output torque is going to change gradually due to the gradual change in the engine operation described above, the fuel injection amount is increased in response to the change, so that the change in the output torque can be accurately suppressed. Become. Even if the output torque changes when the engine operation changes as described above, since the engine operation changes gradually, the output torque change becomes abrupt and the drivability decreases. Connection can be suppressed.
[0101]
(5) As the engine operation for raising the exhaust gas temperature, the fuel injection timing is retarded by the retard amount B, the EGR amount is increased by the amount C, the boost pressure is reduced by the reduced amount D, and the back pressure is increased. The engine is operated in a state where the pressure is increased by the pressure amount D or the like. Such engine operation can be realized without newly providing a special device to the diesel engine 1. Therefore, the filter 18 can be heated to the activation temperature and the particulates can be burned off without the trouble and cost associated with providing the special device.
[0102]
(6) If the engine is idling when the regeneration control is performed, the engine operation for increasing the exhaust temperature by the increase amount A is also performed as the engine operation for increasing the exhaust gas temperature. When the idling rotational speed is increased in this manner, the rotational resistance of the diesel engine 1 increases and thermal efficiency decreases, and the amount of kinetic energy of the engine 1 transmitted to the exhaust as heat also increases. The temperature can be raised. Therefore, in the regeneration control during the idling operation, the exhaust gas temperature can be accurately raised to a value at which the temperature of the filter 18 can be raised to the activation temperature.
[0103]
The above embodiment can be modified, for example, as follows.
It is not always necessary to gradually change the fuel injection amount at the start of the regeneration control and at the time of the regeneration control end command.
[0104]
While the fuel injection amount is increased by the increase amount F corresponding to the difference ΔQ during the regeneration control, the increase amount F may be, for example, a predetermined fixed value.
-It is not always necessary to increase the fuel injection amount during the regeneration control. Even if such an increase in the fuel injection amount is not performed, the regeneration operation is controlled by gradually changing the engine operation between a normal operation that emphasizes thermal efficiency and an operation that is intended to increase the exhaust gas temperature. In this case, a sudden change in output torque can be suppressed.
[0105]
In performing the regeneration control, when the engine operation is changed between the operation in which normal thermal efficiency is emphasized and the operation intended to increase the exhaust gas temperature, it is not always necessary to gradually change the engine operation. Even if such a gradual change in engine operation is not performed, a decrease in output torque during regeneration control can be suppressed by increasing the fuel injection amount during regeneration control.
[0106]
In the regeneration control, the idling speed was increased, the fuel injection timing was retarded, the EGR amount was increased, the supercharging pressure was reduced, and the back pressure was increased in order to increase the exhaust gas temperature. Some may not be performed.
[0107]
-With respect to changes in idle speed, fuel injection timing, EGR amount, supercharging pressure, back pressure, etc. due to execution of regeneration control, the change speed (time required for the change) and the change amount are determined according to the engine operating state. It may be variable. In addition, the change speed and the change amount are different between a change from a normal operation with a focus on thermal efficiency to an operation with a view to increasing the exhaust gas temperature and a change from the operation with a view to raising the exhaust temperature to a normal operation with a focus on heat efficiency. It may be.
[0108]
An intake throttle valve may be provided in the intake passage 2 instead of the exhaust throttle valve 17 in the exhaust passage 8, and this intake throttle valve may play the same role as the exhaust throttle valve 17. Further, both the exhaust throttle valve 17 and the intake throttle valve may be provided.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing an entire diesel engine to which an exhaust gas purification device according to an embodiment is applied.
FIGS. 2A to 2E are time charts showing changes in fuel injection timing, EGR amount, supercharging pressure, back pressure, and fuel injection amount when regeneration control is performed.
FIG. 3 is a time chart showing a transition of an idle rotation speed when regeneration control is performed during an idle operation.
FIG. 4 is an explanatory diagram for explaining how the engine operation at the limit at which the temperature of the filter is raised to the activation temperature changes between during normal operation and during regeneration control.
5 (a) to 5 (c) are graphs showing transition trends of the exhaust gas temperature, the fuel injection amount, and the output torque with respect to the change of the accelerator depression amount.
FIG. 6 is a flowchart showing an execution procedure of reproduction control.
FIG. 7 is a flowchart showing a procedure for gradually changing parameters such as an idle rotation speed, a fuel injection timing, an EGR amount, a supercharging pressure, a back pressure, and a fuel injection amount by a predetermined increase or decrease when performing the regeneration control.
FIG. 8 is a flowchart showing a procedure for holding a predetermined increase or decrease for each parameter such as an idle rotation speed, a fuel injection timing, an EGR amount, a supercharging pressure, a back pressure, and a fuel injection amount when executing the regeneration control.
FIG. 9 is a flowchart showing a procedure for gradually returning parameters such as an idle rotation speed, a fuel injection timing, an EGR amount, a supercharging pressure, a back pressure, and a fuel injection amount to the end of the regeneration control.
FIG. 10 is a flowchart showing a procedure for returning parameters such as an idle rotation speed, a fuel injection timing, an EGR amount, a supercharging pressure, a back pressure, and a fuel injection amount to the end of the regeneration control.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Diesel engine, 2 ... Intake path, 3 ... Combustion chamber, 4 ... Fuel injection valve, 8 ... Exhaust path, 9 ... EGR mechanism, 10 ... EGR path, 11 ... EGR valve, 12 ... Turbocharger, 13 ... Compressor wheel , 14: turbine wheel, 15: bypass passage, 16: waste gate valve, 17: exhaust throttle valve, 18: filter, 20: electronic control unit (regeneration means, increasing means, fuel gradually changing means, operation gradually changing means), 21: supercharging pressure sensor, 22: crank position sensor, 23: back pressure sensor, 24: accelerator pedal, 25: accelerator position sensor.

Claims (9)

An exhaust gas purification device for an internal combustion engine including a filter that collects fine particles contained in exhaust gas of the internal combustion engine,
Regenerating means for controlling the operation of the internal combustion engine so that the exhaust gas temperature rises and performing regeneration control for burning out the fine particles trapped by the filter,
Increasing means for increasing the fuel injection amount of the internal combustion engine during the regeneration control by an amount capable of suppressing a decrease in engine torque due to the regeneration control;
An exhaust gas purifying apparatus for an internal combustion engine, comprising: The exhaust gas purifying apparatus for an internal combustion engine according to claim 1,
The regeneration means executes the regeneration control by changing the operation of the internal combustion engine from an operation focusing on thermal efficiency to an operation intended to increase the exhaust gas temperature,
At the start of the regeneration control, the engine operation changes from the operation with an emphasis on thermal efficiency to the operation intended to increase the exhaust gas temperature, and at the end of the regeneration control, from the operation with the intention to increase the exhaust gas temperature to the operation with an emphasis on the thermal efficiency An exhaust gas purification device for an internal combustion engine, further comprising a gradual operation change means for gradually changing at least one of engine operation changes. The exhaust gas purifying apparatus for an internal combustion engine according to claim 1 or 2,
An exhaust gas purifying apparatus for an internal combustion engine, further comprising a fuel gradual change means for gradually changing a fuel injection amount at least at a time when the fuel injection amount is increased by the amount increasing means and at a time when the fuel amount is increased. . An exhaust gas purification device for an internal combustion engine including a filter that collects fine particles contained in exhaust gas of the internal combustion engine,
By changing the operation of the internal combustion engine from an operation that emphasizes thermal efficiency to an operation that intends to increase the exhaust gas temperature, the exhaust gas temperature of the engine is increased to execute regeneration control for burning out the fine particles trapped by the filter. Reproduction means,
At the start of the regeneration control, the engine operation changes from the operation with an emphasis on thermal efficiency to the operation intended to increase the exhaust gas temperature, and at the end of the regeneration control, from the operation with the intention to increase the exhaust gas temperature to the operation with an emphasis on the thermal efficiency At least one of the engine operation change, operation gradual change means for gradually performing the change,
An exhaust gas purifying apparatus for an internal combustion engine, comprising: The engine according to claim 1, wherein the regenerating means performs the engine operation for increasing the exhaust gas temperature in a state in which a throttle valve provided in an intake / exhaust system of the internal combustion engine is controlled to be more closed than a normal engine operation that emphasizes thermal efficiency. An exhaust purification device for an internal combustion engine according to any one of claims 1 to 4. The internal combustion engine according to any one of claims 1 to 5, wherein, as the engine operation for increasing the exhaust gas temperature, the regeneration unit performs the operation in a state where the supercharging pressure provided by the supercharging system provided in the internal combustion engine is reduced. Engine exhaust purification device. The engine according to any one of claims 1 to 6, wherein the regenerating means performs the engine operation in a state where the fuel injection timing of the internal combustion engine is controlled to be more retarded than the engine operation that emphasizes thermal efficiency, as the engine operation for increasing the exhaust gas temperature. An exhaust purification device for an internal combustion engine according to claim 1. The regeneration means executes the engine operation as an engine operation for raising the exhaust gas temperature in a state in which the amount of exhaust gas recirculation by an exhaust gas recirculation mechanism provided in the internal combustion engine is controlled to be increased from the engine operation that emphasizes thermal efficiency. An exhaust purification device for an internal combustion engine according to any one of claims 1 to 7. The engine according to any one of claims 1 to 8, wherein the regeneration unit performs an idle operation in a state in which an idle rotation speed is increased as compared with a normal state, as the engine operation for increasing the exhaust gas temperature during the idle operation. Exhaust purification device for internal combustion engine.

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